DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Prosecution Reopened
In view of the Appeal Brief filed on 11/12/2025, PROSECUTION IS HEREBY REOPENED. New grounds of rejection are set forth below.
To avoid abandonment of the application, appellant must exercise one of the following two options:
(1) file a reply under 37 CFR 1.111 (if this Office action is non-final) or a reply under 37 CFR 1.113 (if this Office action is final); or,
(2) initiate a new appeal by filing a notice of appeal under 37 CFR 41.31 followed by an appeal brief under 37 CFR 41.37. The previously paid notice of appeal fee and appeal brief fee can be applied to the new appeal. If, however, the appeal fees set forth in 37 CFR 41.20 have been increased since they were previously paid, then appellant must pay the difference between the increased fees and the amount previously paid.
A Supervisory Patent Examiner (SPE) has approved of reopening prosecution by signing below:
/IN SUK C BULLOCK/ Supervisory Patent Examiner, Art Unit 1772
Status of Claims
Claims 1-20 and 22-26 are pending. Claim 20 is withdrawn from consideration.
Response to Arguments
Applicant’s arguments, see Appeal Brief, filed 11/12/2025, with respect to the 103 rejections have been fully considered but they are not persuasive.
Applicant argues that none of the relied upon references teach or suggest “bypassing at least one stage of the multiple stages using a first series of valves to redirect the feedwater and a second series of valves to redirect energy from steam…wherein the redirected energy from steam is redirected energy from steam of at least one remaining stage of the multiple stages for reuse across another remaining stage of the multiple stages,” as is required by claim 1.
Applicant’s arguments are primarily concerned with Xu, which is relied upon to teach the specific concept of bypassing steam and feed around one or more middle stages of a multiple effect evaporation system. Applicant’s arguments against Xu are made on the basis that Xu allegedly does not teach bypassing steam/energy in a manner which involves “redirecting” steam/energy “of at least one remaining stage of the multiple stages across another remaining stage of multiple stages”. Examiner maintains that Xu does teach redirecting steam in a manner consistent with the claim language for at least the reasons articulated in the 8/14/2025 Advisory Action.
Regardless, for the sake of argument, even if it were ruled that Xu does not teach bypassing by redirecting steam/energy from one evaporator stage to another, there are other prior art references which do. Most notable among the references which Examiner has discovered as of this Office Action are: Craney (US 531,912), Moore (US 1,098,825), Bauer (US 1,143,744), and GB 1497429.
Craney expressly teaches a multiple effect evaporator system having a series of valves which can be used to, for example, bypass a middle evaporator stage 2 by redirecting steam of a third evaporator stage 3 away from the middle evaporator stage and to a first evaporator stage (Figures 3-8, page 1 lines 24-104, special emphasis on Figures 7 and 8).
Moore expressly teaches a multiple effect evaporator system having a series of valves 14, 15, and 15a which can be used to bypass one or more one or more middle evaporator stages by redirecting steam away from said one or more middle evaporator stages via manifold 13 to a subsequent evaporator stage (Figure 1 and 2, page 2 Lines 70-90). Moore also at least suggests rerouting feed liquid (“solution”) around the evaporators to be bypassed (page 7 Lines 49-55).
Bauer expressly teaches a process of operating a multiple effect evaporator system wherein: a series of valves 34, 35, and 41 is used to redirect steam from a first evaporator stage (pan) C through pipe 40, away from a middle stage B, and onward to a final stage A (Figure 2, Page 3 Line 110-Page 4 Line 17); and another series of valves 20’, 50, 51 is used to redirect feed liquid from the first evaporator stage C through valve 51, away from the middle stage B, and onward to the final stage A (Figure 2, Page 3 Line 110-Page 4 Line 17). Applicant’s attention is further directed to the disclosure of Page 2 Line 93-Page 3 Line 5.
GB 1497429 teaches bypassing at least steam around a middle stage (evaporator effect) 1 of a multiple effect evaporator system using a series of valves (Figure 3, page 3 Line 105-page 4 Line 5). Notably, GB 1497429 expressly describes this bypassing process as allowing an evaporator stage to be “isolated” from the flow of steam, i.e. from the “vapour circulating system” (page 3 Lines 115-118). GB 1497429 does not use the terms “redirect” or “reroute” (or any form thereof) and yet, it is clear from the illustration of Figure 3 that the steam bypassing process of GB 1497429 does involve what inarguably amounts to the redirecting of steam. Thus, Examiner respectfully asserts that the disclosure of GB 1497429 shows that Applicant assigns too much significance to: i) Xu’s use of the term “isolating”; and ii) the fact that Xu does not use to the term “redirect” or the like describe the steam bypass operation therein.
Of further note to the matter of bypassing steam by rerouting are the disclosures of Peck (US 329,072), Farnham (US 472,209), and Carney (US 525,486), hereafter referred to as Carney II. Peck at least suggests using a series of valves h2, h3, and h4 to bypass one or more evaporator stages, including middle evaporator stages, by redirecting steam away from the bypassed evaporator(s) to a subsequent evaporator (Figures 1 and 2, Page 4 Line 120-page 5 Line 5). While Examiner has not presently discovered any express disclosures in Farnham and Carney II to bypass operations involving redirection of steam, the valve arrangements taught therein (see Farnham: Figures 1 and 2; Carney II: Figures 1, 2, 4, 5, and 6) are nevertheless capable of such bypass operations.
If arguendo the claimed steam bypass arrangement is patentably distinct from that of Xu, it remains that it is not patentably distinct from the steam bypass arrangements taught/suggested by Craney (US 531,912), Moore (US 1,098,825), Bauer (US 1,143,744), Peck (US 329,072) and GB 1497429. Furthermore, without conceding that claimed steam bypassing is different from that of Xu, Examiner nevertheless notes that the steam bypassing taught by Craney (US 531,912), Moore (US 1,098,825), Bauer (US 1,143,744), and GB 1497429 more closely resemble the steam bypassing as disclosed in Applicant’s specification. The same is true of the steam bypassing that is taught or at least suggested by of Peck (US 329,072). For these reasons, Examiner has chosen to withdraw the rejections made in reliance on Xu in favor of rejections made in reliance on Bauer.
Examiner has chosen to rely on Bauer, as the disclosure of Bauer seems to offer the most clear and complete teaching to the claimed bypass arrangement of any single reference currently available to Examiner. However, Examiner holds that, in lieu of reliance on Bauer, it would also be proper to rely on Craney (US 531,912), Moore (US 1,098,825), Peck (US 329,072), or GB 1497429 to teach the claimed steam bypass arrangement in combination (if necessary) with a reference which teaches the claimed feed bypass arrangement. Such references include: Xu, Bauer, and previously cited Chirico (US 3,258,060) (See Figure 1, Columns 4 and 5 of Chirico).
The particular arguments made by Applicant in the 11/12/2025 Appeal brief have been considered, but are moot, as they do not apply to the new rejections set forth below.
Claim Interpretation
The claims recite limitations to using a first series of valves to redirect feedwater and a second series of valves to redirect energy from steam.
Applicant’s specification as originally filed does not contain any special definition of the word “redirect”. Accordingly, “redirect” as used in the claims is given its broadest reasonable interpretation consistent with the specification (MPEP 2111). “Under a broadest reasonable interpretation (BRI), words of the claim must be given their plain meaning, unless such meaning is inconsistent with the specification,” (MPEP 2111.01(I)). “’[T]he ordinary and customary meaning of a claim term is the meaning that the term would have to a person of ordinary skill in the art in question at the time of the invention, i.e., as of the effective filing date of the patent application.’” (MPEP 2111.01(III).
Merriam-Webster defines “redirect” as: “to change the course or direction of”.
Oxford English Dictionary defines “redirect” as: “To give a new direction to; to turn (thoughts, attention, energy, etc.) upon a new object; to send (a person or thing) in a different direction or to a different place.”
The Brittanica Dictionary defines “redirect” as:
1: “to change the path or direction of (something)”; or
2: “to use (something) for a different purpose”.
With the forgoing definitions in mind, under the broadest reasonable interpretation, Examiner interprets the claim language to the use of a first series of valves to redirect feedwater as being satisfied by at least any method step where actuation of a valve or valves: i) changes the course or direction of at least a portion of a feedwater stream; ii) sends at least a portion of a feedwater stream in a different direction or to a different place than it was otherwise headed; iii) changes the path or direction of at least a portion of a feedwater stream; and/or iv) causes at least a portion of a feedwater stream to be used for a different purpose.
Likewise, Examiner interprets the claim language to the use of a second series of valves to redirect energy from steam as being satisfied by at least any method step where actuation of a valve or valves: i) changes the course or direction of at least a portion of a steam stream (or energy from a steam stream); ii) sends at least a portion of a steam stream (or energy from a steam stream) in a different direction or to a different place than it was otherwise headed; iii) changes the path or direction of at least a portion of a steam stream (or energy from a steam stream); and/or iv) causes at least a portion of a steam stream (or energy from a steam stream) to be used for a different purpose.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or non-obviousness.
Claims 1-11 and 23-24 is/are rejected under 35 U.S.C. 103 as being unpatentable over Efrat et al. (US 2018/0093307), hereafter referred to as Efrat, in view of Efrat (US 2018/0372434), hereafter referred to as Efrat II, Bauer (US 1,143,744), and Sparrow et al. (US 2014/0061958), hereafter referred to as Sparrow.
With regard to claim 1: Efrat teaches a method of cleaning a water treatment system (abstract), the method comprising:
a) providing a water treatment system (evaporator) having elements (heat transfer pipes) susceptible to scale formation during operation of the water treatment system (abstract, paragraph [0034]).
Efrat teaches that “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added). The evaporators in Figures 1A and 1B are water treatment systems (multi-effect evaporator) 100 comprising multiple stages (effects) 101, each of stage 101 of the multiple stages having elements (heat transfer pipes/tubes) 110 susceptible to scale formation during operation of the water treatment system, each stage 101 of the multiple stages fluidly connected to one another, and each stage of the multiple stages comprising a condenser chamber (inner portion of tubes 110) and an evaporation chamber (chamber surrounding the outer portion of tubes 110) (Figures 1A and 1B, paragraphs [0003]-[0004] and [0007]). By teaching that the “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added), Efrat is disclosing embodiments comprising a step of providing a water treatment system wherein the water treatment system is the water treatment system of Figure 1A or Figure 1B.
Thus, Efrat teaches (i.e. anticipates) a step of a) providing a water treatment system (multi-effect evaporator) 100 comprising multiple stages (effects) 101, each of stage 101 of the multiple stages having elements (heat transfer pipes/tubes) 110 susceptible to scale formation during operation of the water treatment system 100, each stage 101 of the multiple stages fluidly connected to one another, and each stage of the multiple stages comprising a condenser chamber (inner portion of tubes 110) and an evaporation chamber (chamber surrounding the outer portion of tubes 110) (Figures 1A and 1B, paragraphs [0003]-[0004], [0007], and [0034]).
In the unlikely alternative, Efrat’s teaching that the “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added), would serve as a strong suggestion that Efrat’s method be carried out on the systems of Figure 1A and/or Figure 1B. Efrat teaches that “scale formation on heat transfer surfaces remains one of the most severe problems in the design and operation of multiple-effect distillers for seawater desalination, having a highly deleterious effect on the specific energy consumption and production capacity,” (paragraph [0007]), thus providing clear indication that the systems of Figures 1A and 1B would benefit from Efrat’s method being carried out on said systems.
In the unlikely event that it were not already the case in base Efrat, it would have been obvious to one of ordinary skill in the art to modify Efrat by carrying out the method of Efrat on the water treatment system of Figure 1A and/or the water treatment system of Figure 1B, i.e. such that Efrat were to comprise a step of a) providing a water treatment system (multi-effect evaporator) 100 comprising multiple stages (effects) 101, each of stage 101 of the multiple stages having elements (heat transfer pipes/tubes) 110 susceptible to scale formation during operation of the water treatment system 100, each stage 101 of the multiple stages fluidly connected to one another, and each stage of the multiple stages comprising a condenser chamber (inner portion of tubes 110) and an evaporation chamber (chamber surrounding the outer portion of tubes 110), in order to obtain a predictably functional method which is: 1) congruent with Efrat’s express suggestions (i.e. those in paragraph [0034]), and 2) beneficial to the water treatment system, i.e. the water treatment system of Figure 1A and/or Figure 1B, as indicated by the teachings of paragraph [0007]).
Efrat’s method of cleaning a water treatment system further comprises: b) depositing a conditioning layer (sacrificial layer) onto at least some of the elements (heat transfer pipes) susceptible to scale formation (abstract, paragraph [0034]).
Efrat teaches that “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added). The evaporators in Figures 1A and 1B are water treatment systems (multi-effect evaporator) 100 comprising multiple stages (effects) 101, each of stage 101 of the multiple stages having elements (heat transfer pipes/tubes) 110 susceptible to scale formation during operation of the water treatment system, each stage 101 of the multiple stages fluidly connected to one another, and each stage of the multiple stages comprising a condenser chamber (inner portion of tubes 110) and an evaporation chamber (chamber surrounding the outer portion of tubes 110) (Figures 1A and 1B, paragraphs [0003]-[0004] and [0007]). By teaching that the “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added), Efrat is disclosing embodiments comprising a step of providing a water treatment system wherein the water treatment system is the water treatment system of Figure 1A or Figure 1B.
Thus, Efrat teaches (i.e. anticipates) a step of b) depositing a conditioning layer (sacrificial layer) onto at least some of the elements (heat transfer pipes/tubes) 110 susceptible to scale formation (Figures 1A and 1B, paragraphs [0003]-[0004], [0007], and [0034]).
In the unlikely alternative, Efrat’s teaching that the “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added), would serve as a strong suggestion that Efrat’s method be carried out on the systems of Figure 1A and/or Figure 1B. Efrat teaches that “scale formation on heat transfer surfaces remains one of the most severe problems in the design and operation of multiple-effect distillers for seawater desalination, having a highly deleterious effect on the specific energy consumption and production capacity,” (paragraph [0007]), thus providing clear indication that the systems of Figures 1A and 1B would benefit from Efrat’s method being carried out on said systems.
In the unlikely event that it were not already the case in base Efrat, it would have been obvious to one of ordinary skill in the art to modify Efrat by carrying out the method of Efrat on the water treatment system of Figure 1A and/or the water treatment system of Figure 1B, i.e. such that Efrat were to comprise a step of b) depositing a conditioning layer (sacrificial layer) onto at least some of the elements (heat transfer pipes/tubes) 110 susceptible to scale formation, in order to obtain a predictably functional method which is: 1) congruent with Efrat’s express suggestions (i.e. those in paragraph [0034]), and 2) beneficial to the water treatment system, i.e. the water treatment system of Figure 1A and/or Figure 1B, as indicated by the teachings of paragraph [0007]).
Efrat’s method of cleaning a water treatment system further comprises: c) operating the water treatment system (evaporator) by allowing feedwater to flow into the water treatment system and heating the feedwater, thus causing scale to form on the conditioning layer (sacrificial layer) (abstract, paragraph [0035]).
Efrat teaches that “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added). The evaporators in Figures 1A and 1B are water treatment systems (multi-effect evaporator) 100 comprising multiple stages (effects) 101, each of stage 101 of the multiple stages having elements (heat transfer pipes/tubes) 110 susceptible to scale formation during operation of the water treatment system, each stage 101 of the multiple stages fluidly connected to one another, and each stage of the multiple stages comprising a condenser chamber (inner portion of tubes 110) and an evaporation chamber (chamber surrounding the outer portion of tubes 110) (Figures 1A and 1B, paragraphs [0003]-[0004] and [0007]), wherein in operation of said systems 100, energy from steam produced by heating the feedwater in one stage 101 of the multiple stages is transferred to another stage 101 of the multiple stages for reuse across the multiple stages, i.e. by transferring steam that is produced in one stage to the interior of the tubes 110 in another stage 101 to be condensed therein, thus transferring heat from said steam to the stage in which it is condensed (Figures 1A and 1B, paragraphs [0003]-[0004]). By teaching that the “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added), Efrat is disclosing embodiments comprising a step of providing a water treatment system wherein the water treatment system is the water treatment system of Figure 1A or Figure 1B.
Thus, Efrat teaches (i.e. anticipates) a step of c) operating the water treatment system by allowing feedwater to flow into the water treatment system and heating the feedwater, thus causing scale to form on the conditioning layer, wherein energy from steam produced by heating the feedwater in one stage 101 of the multiple stages is transferred to another stage 101 of the multiple stages for reuse across the multiple stages, i.e. by transferring steam that is produced in one stage to the interior of the tubes 110 in another stage 101 to be condensed therein, thus transferring heat from said steam to the stage in which it is condensed (Figures 1A and 1B, paragraphs [0003]-[0004], [0007], and [0034]-[0035]).
In the unlikely alternative, Efrat’s teaching that the “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added), would serve as a strong suggestion that Efrat’s method be carried out on the systems of Figure 1A and/or Figure 1B. Efrat teaches that “scale formation on heat transfer surfaces remains one of the most severe problems in the design and operation of multiple-effect distillers for seawater desalination, having a highly deleterious effect on the specific energy consumption and production capacity,” (paragraph [0007]), thus providing clear indication that the systems of Figures 1A and 1B would benefit from Efrat’s method being carried out on said systems.
In the unlikely event that it were not already the case in base Efrat, it would have been obvious to one of ordinary skill in the art to modify Efrat by carrying out the method of Efrat on the water treatment system of Figure 1A and/or the water treatment system of Figure 1B, i.e. such that Efrat were to comprise a step of c) operating the water treatment system by allowing feedwater to flow into the water treatment system and heating the feedwater, thus causing scale to form on the conditioning layer, wherein energy from steam produced by heating the feedwater in one stage 101 of the multiple stages is transferred to another stage 101 of the multiple stages for reuse across the multiple stages, i.e. by transferring steam that is produced in one stage to the interior of the tubes 110 in another stage 101 to be condensed therein, thus transferring heat from said steam to the stage in which it is condensed, in order to obtain a predictably functional method which is: 1) congruent with Efrat’s express suggestions (i.e. those in paragraph [0034]), and 2) beneficial to the water treatment system, i.e. the water treatment system of Figure 1A and/or Figure 1B, as indicated by the teachings of paragraph [0007]).
Efrat’s method of cleaning a water treatment system further comprises: d) removing the conditioning layer (sacrificial layer), thus also removing the scale (abstract, paragraph [0035]), wherein the removal of the conditioning layer is accomplished through the use of a chemical cleaner (paragraph [0023], claim 13).
Efrat teaches that “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added). The evaporators in Figures 1A and 1B are water treatment systems (multi-effect evaporator) 100 comprising multiple stages (effects) 101, each of stage 101 of the multiple stages having elements (heat transfer pipes/tubes) 110 susceptible to scale formation during operation of the water treatment system, each stage 101 of the multiple stages fluidly connected to one another, and each stage of the multiple stages comprising a condenser chamber (inner portion of tubes 110) and an evaporation chamber (chamber surrounding the outer portion of tubes 110) (Figures 1A and 1B, paragraphs [0003]-[0004] and [0007]), wherein in operation of said systems 100, energy from steam produced by heating the feedwater in one stage 101 of the multiple stages is transferred to another stage 101 of the multiple stages for reuse across the multiple stages, i.e. by transferring steam that is produced in one stage to the interior of the tubes 110 in another stage 101 to be condensed therein, thus transferring heat from said steam to the stage in which it is condensed (Figures 1A and 1B, paragraphs [0003]-[0004]). By teaching that the “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added), Efrat is disclosing embodiments comprising a step of providing a water treatment system wherein the water treatment system is the water treatment system of Figure 1A or Figure 1B.
Thus, Efrat teaches (i.e. anticipates) a step of d) removing the conditioning layer (sacrificial layer), thus also removing the scale, wherein the removal of the conditioning layer is accomplished through the use of a chemical cleaner, wherein said step d) is carried out on/in the water treatment system of Figure 1A and/or Figure 1B (Figures 1A and 1B, paragraphs [0003]-[0004], [0007], 0023], and [0034]-[0035], claim 13).
In the unlikely alternative, Efrat’s teaching that the “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added), would serve as a strong suggestion that Efrat’s method be carried out on the systems of Figure 1A and/or Figure 1B. Efrat teaches that “scale formation on heat transfer surfaces remains one of the most severe problems in the design and operation of multiple-effect distillers for seawater desalination, having a highly deleterious effect on the specific energy consumption and production capacity,” (paragraph [0007]), thus providing clear indication that the systems of Figures 1A and 1B would benefit from Efrat’s method being carried out on said systems.
In the unlikely event that it were not already the case in base Efrat, it would have been obvious to one of ordinary skill in the art to modify Efrat by carrying out the method of Efrat on the water treatment system of Figure 1A and/or the water treatment system of Figure 1B, i.e. such that Efrat were to comprise a step of d) removing the conditioning layer (sacrificial layer), thus also removing the scale, wherein the removal of the conditioning layer is accomplished through the use of a chemical cleaner, wherein said step d) is carried out on/in the water treatment system of Figure 1A and/or Figure 1B, in order to obtain a predictably functional method which is: 1) congruent with Efrat’s express suggestions (i.e. those in paragraph [0034]), and 2) beneficial to the water treatment system, i.e. the water treatment system of Figure 1A and/or Figure 1B, as indicated by the teachings of paragraph [0007]).
Efrat is silent to step d) comprising bypassing at least one stage of the multiple stages using a first series of valves to redirect the feedwater and a second series of valves to redirect energy from steam and removing the conditioning layer of the at least one stage of the multiple stages that has been bypassed through use of one or more acids during the operation of the water treatment system, thus also removing the scale of the at least one stage of the multiple stages that has been bypassed, while maintaining a transfer of the redirected energy from steam, wherein the redirected energy from steam is redirected energy from steam of at least one remaining stage of the multiple stages for reuse across another remaining stage of the multiple stages, thereby preventing a complete shutdown of the water treatment system.
However, bypassing during operations of cleaning scale from multi-stage evaporators is known in the art. For example, Efrat II teaches a method of operating a multistage evaporator system in a cleaning mode, wherein at least one stage of a plurality of stages is bypassed (physically separated) using a series of valves, and the at least one stage that has been bypassed is treated with a cleaning agent so as to remove scale from the at least one stage that has been bypassed during operation of the multistage evaporator system, while maintaining a transfer of energy from steam of at least one remaining stage of the plurality of stages for reuse across the at least one remaining stage, thereby preventing a complete shutdown of the system (abstract, Figure 1, paragraphs [0037]-[0040]). A person having ordinary skill in the art would recognize that the ability to clean a single stage while keeping the remainder of the evaporator system (i.e. outside of the stage being cleaned) in operation is advantageous, as it allows for cleaning to be carried out with minimal disruption to the evaporator’s productivity.
It is acknowledged that Efrat II does not teach bypassing an intermediate stage (i.e. by redirecting energy from steam originating from a remaining stage of the multiple stages while maintaining a transfer of the redirected energy from steam originating from the remaining stage the multiple stages for reuse across another remaining stage of the multiple stages). Instead Efrat II only teaches bypassing a first stage, or a first group of stages. It is acknowledged that Efrat II does not teach the use of a both a first set of valves to reroute feedwater and a second set of valves to reroute steam.
However, bypass arrangements for bypassing an intermediate stage (i.e. by redirecting energy from steam originating from a remaining stage of the multiple stages while maintaining a transfer of the redirected energy from steam originating from the remaining stage the multiple stages for reuse across another remaining stage of the multiple stages) are known in the art. It is further known in the art for such bypass arrangements to make use of a first set of valve to redirect feed liquid and a second set of valves to redirect energy from steam.
For example, Bauer expressly teaches a process of operating a multiple effect evaporator system wherein: a series of valves 34, 35, and 41 is used to redirect steam from a first evaporator stage (pan) C through pipe 40, away from a middle stage B, and onward to a final stage A (Figure 2, Page 3 Line 110-Page 4 Line 17); and another series of valves 20’, 50, 51 is used to redirect feed liquid from the first evaporator stage C through valve 51, away from the middle stage B, and onward to the final stage A (Figure 2, Page 3 Line 110-Page 4 Line 17). Applicant’s attention is further directed to the disclosure of Page 2 Line 93-Page 3 Line 5.
A person having ordinary skill in the art would recognize that it would be advantageous to bypass specifically an intermediate stage for the purposes of cleaning said intermediate stage as opposed to merely a first stage or a first group of stages (as is done in Efrat II), as bypassing an intermediate stage will allow specifically the intermediate stage to be cleaned on its own without shutting down all of the evaporator stages or an entire first group of evaporator stages. Indeed, Bauer provides express indication that the middle stage (pan) B can be bypassed for the purposes of cleaning said stage without shutting down the first and final stages C and A (Page 3 Lines 112-116).
With respect to the use of both a first serries of valves and a second series of valves, a person having ordinary skill in the art would recognize that having both a first and second serries of valves would be advantageous, if not absolutely necessary, as it is understood that, in the context of multi-effect evaporator systems, product steam (and thus the energy therein) and feedwater are separate flows which should not be combined into a single flow. Therefore, when considering bypass arrangements for a multi-effect evaporator system, a person having ordinary skill in the art would find the use of first and second sets of valves desirable in order to enable both steam and feedwater flows to bypass a particular stage.
It would have been obvious to one of ordinary skill in the art before the effective filing date to modify Efrat in view of Efrat II and Bauer by carrying out the step of removing the conditioning layer, and thus the scale, as a step of d) bypassing at least one stage of the multiple stages using a first series of valves to redirect the feedwater and a second series of valves to redirect energy from steam and removing the conditioning layer of the at least one stage of the multiple stages that has been bypassed through use of one or more acids during the operation of the water treatment system, thus also removing the scale of the at least one stage of the multiple stages that has been bypassed, while maintaining a transfer of the redirected energy from steam, wherein the redirected energy from steam is redirected energy from steam of at least one remaining stage of the multiple stages for reuse across another remaining stage of the multiple stages, thereby preventing a complete shutdown of the water treatment system, in order to obtain a method wherein: i) both steam and feedwater flows can be made to bypass a particular stage, and ii) scale can be removed from an intermediate stage of the multiple stages without shutting down all of the evaporator stages or an entire first group of evaporator stages, such that scale can be removed from the intermediate stage of the water treatment system (evaporator) with minimal disruption to the evaporator’s productivity.
Modified Efrat does not explicitly teach that the chemical cleaner comprises one or more acids.
However, Efrat does not identify any specific examples of chemical cleaners. Thus, a person having ordinary skill in the art would look elsewhere to find examples of suitable chemical cleaners.
It is notoriously well known in the art to remove scale using acid-based cleaners. For example, Sparrow teaches a method for concentrating a solution using evaporation (Abstract, Paragraph [0001]), the method comprising the use of a “clean-in-place” solution having descaling capability, wherein the clean in place solution may comprise an acid (paragraph [0064] and [0140]). Notably, Sparrow teaches that “dilute citric acid may be used to de-scale calcium carbonate,” (paragraph [0140]), clearly indicating that citric acid solutions are suitable for removing calcium carbonate scaling. Efrat teaches that the conditioning layer (sacrificial layer) may be calcium carbonate (paragraphs [0034], [0041], and [0042]). Thus, in view of the combined teachings of Efrat and Sparrow, a person having ordinary skill in the art would have a reasonable expectation that an acid cleaning solution, e.g. a citric acid solution, could be used as the chemical cleaner for removing the conditioning layer (sacrificial layer) in Efrat.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Efrat in view of Sparrow by using an acid-based cleaning solution, i.e. a solution comprising one or more acids, as the chemical cleaner for removing the conditioning layer, and thus the scale, in Efrat, in order to obtain a predictably successful method of removing scale in accordance with the teachings of Efrat.
With regard to claim 2: In modified Efrat, the conditioning layer comprises a carbonate (Efrat: paragraphs [0034], [0041], and [0042]).
With regard to claim 3: In modified Efrat, the conditioning layer may be calcium carbonate or magnesium carbonate (Efrat: paragraphs [0034], [0041], and [0042]).
With regard to claim 4: In modified Efrat, the conditioning layer is deposited onto at least some of the elements susceptible to scale formation from an aqueous carbonate solution by one or more of evaporation (i.e. by supplying water to an evaporator in operation, wherein the water comprises the material [e.g. carbonate] for forming the conditioning layer in supersaturation) and chemical treatment (i.e. by raising a pH of supplied water containing the material for forming the conditioning layer, and/or by adding the material to the supplied water to increase its concentration and facilitate the precipitation thereof) (Efrat: Paragraphs [0016]-[0021]).
With regard to claim 5: In modified Efrat, the conditioning layer is deposited onto at least some of the elements susceptible to scale formation from an aqueous carbonate solution by one or more of evaporation (i.e. by supplying water to an evaporator in operation, wherein the water comprises the material [e.g. carbonate] for forming the conditioning layer in supersaturation) and chemical treatment (i.e. by raising a pH of supplied water containing the material for forming the conditioning layer, and/or by adding the material to the supplied water to increase its concentration and facilitate the precipitation thereof) (Efrat: Paragraphs [0016]-[0021]).
In modified Efrat, the conditioning layer may be calcium carbonate (Efrat: paragraphs [0034], [0041], and [0042]).
In modified Efrat, the chemical treatment may be one or more of:
Adding sufficient calcium-containing chemical species and carbonate containing species (e.g. a “first material” for forming the sacrificial layer, wherein said first material may comprise at least carbonate and calcium) to the aqueous solution to increase molar concentrations of calcium and carbonate ions beyond their solubility product, i.e. adding the first material (a material which may comprise at least calcium and carbonate) for forming the conditioning layer to the supplied water to increase its concentration (note: increase in concentration necessarily involves an increase in molar concentration) and facilitate precipitation of the first material (Efrat: Paragraphs [0018], [0020], and [0021]).
And adding sufficient carbonate containing species (e.g. a “first material” for forming the sacrificial layer, wherein said first material may comprise at least carbonate and calcium) to the aqueous solution to increase molar concentrations of calcium and carbonate ions beyond their solubility product, i.e. adding the first material (a material which may comprise at least calcium and carbonate) for forming the conditioning layer to the supplied water to increase its concentration (note: increase in concentration necessarily involves an increase in molar concentration) and facilitate precipitation of the first material (Efrat: Paragraphs [0018], [0020], and [0021]).
Examiner notes that the chemical treatment may also involve increasing pH of the aqueous solution (Efrat: paragraphs [0017] and [0020]).
With regard to claim 6: Modified Efrat is silent to the conditioning layer having a thickness of less than 1 mm.
However, a person having ordinary skill in the art will recognize that the thickness of the conditioning layer is a result effective variable. In particular, a person having ordinary skill in the art will recognize that the conditioning layer will increase the heat transfer resistance of the heat transfer elements, and that a thicker conditioning layer will result in a greater increase in heat transfer resistance. Thus, a person having ordinary skill in the art would recognize that it would be desirable for the conditioning layer to be as thin as possible, as the heat transfer elements in Efrat will be more effective when the conditioning layer is thinner. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Efrat by optimizing the thickness of the conditioning layer to be as thin as possible, i.e. less than 1 mm, in order to obtain a method wherein the conditioning layer’s impact on heat transfer is minimized.
With regard to claim 7: Modified Efrat is silent to the conditioning layer having a thickness of less than 1 micron.
However, a person having ordinary skill in the art will recognize that the thickness of the conditioning layer is a result effective variable. In particular, a person having ordinary skill in the art will recognize that the conditioning layer will increase the heat transfer resistance of the heat transfer elements, and that a thicker conditioning layer will result in a greater increase in heat transfer resistance. Thus, a person having ordinary skill in the art would recognize that it would be desirable for the conditioning layer to be as thin as possible, as the heat transfer elements in Efrat will be more effective when the conditioning layer is thinner. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Efrat by optimizing the thickness of the conditioning layer to be as thin as possible, i.e. less than 1 micron, in order to obtain a method wherein the conditioning layer’s impact on heat transfer is minimized.
With regard to claim 8: Modified Efrat is silent to the one or more acids, i.e. the acid-based cleaning solution, having a pH lower than 6.
However, Sparrow teaches that the pH of a cleaning solution should be decreased for the purposes of descaling carbonates (paragraphs [0064] and [0196]). As discussed above, the conditioning layer in modified Efrat comprises a carbonate, e.g. calcium carbonate (Efrat: paragraphs [0034], [0041], and [0042]). Thus, a person having ordinary skill in the art would recognize the pH of the acid-based cleaning solution in modified Efrat as being a result effective variable. Specifically, person having ordinary skill in the art would recognize that the pH would need to be low enough to properly and efficiently remove the conditioning layer. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Efrat in view of Sparow by configuring the acid cleaning solution, i.e. the solution comprising one or more acids, to have a pH suitably low for removing the conditioning layer, i.e. a pH lower than 6, in order to obtain a method wherein the acid cleaning solution is capable of removing the conditioning layer as intended.
With regard to claim 9: Modified Efrat is silent to the one or more acids, i.e. the acid-based cleaning solution, having a pH lower than 3.
However, Sparrow teaches that the pH of a cleaning solution should be decreased for the purposes of descaling carbonates (paragraphs [0064] and [0196]). As discussed above, the conditioning layer in modified Efrat comprises a carbonate, e.g. calcium carbonate (Efrat: paragraphs [0034], [0041], and [0042]). Thus, a person having ordinary skill in the art would recognize the pH of the acid-based cleaning solution in modified Efrat as being a result effective variable. Specifically, person having ordinary skill in the art would recognize that the pH would need to be low enough to properly and efficiently remove the conditioning layer. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Sparrow in view of Efrat by configuring the acid cleaning solution, i.e. the solution comprising one or more acids, to have a pH suitably low for removing the conditioning layer, i.e. a pH lower than 3, in order to obtain a method wherein the acid cleaning solution is capable of removing the conditioning layer as intended.
With regard to claim 10: In modified Efrat, the one or more acids may be citric acid in a dilute solution (Sparrow: paragraph [0140]).
Modified Efrat does not explicitly teach that the solution of citric acid is an aqueous solution. However, given Sparrow’s teachings that the cleaning solution is formed with water (paragraph [0140]). It is understood that the solution of citric acid is implicitly an aqueous solution.
In the alterative, it is well understood that citric acid has good solubility in water, and that water is a widely available and effective solvent in general. This knowledge, in combination with Sparrow’s teachings regarding the cleaning solution being water based (paragraphs [0064] and [0140]), would suggest to one of ordinary skill in the art that the citric acid solution could be successfully constituted as an aqueous solution.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Efrat in view of Sparrow by forming the solution of citric acid as an aqueous solution, in order to obtain a predictably functional citric acid cleaning solution formed using an effective and readily available solvent (i.e. water).
With regard to claim 11: In modified Efrat, the one or more acids may be citric acid (Sparrow: paragraph [0140]).
With regard to claim 23: As discussed in the rejection of claim 1 above, the method modified Efrat comprises a step of c) operating the water treatment system by allowing feedwater to flow into the water treatment system and heating the feedwater, thus causing scale to form on the conditioning layer, wherein energy from steam produced by heating the feedwater in one stage 101 of the multiple stages is transferred to another stage 101 of the multiple stages for reuse across the multiple stages, i.e. by transferring steam that is produced in one stage to the interior of the tubes 110 in another stage 101 to be condensed therein, thus transferring heat from said steam to the stage in which it is condensed (Efrat: Figures 1A and 1B, paragraphs [0003]-[0004], [0007], and [0034]-[0035]). See rejection of claim 1 above for further details.
Thus, it is understood that modified Efrat represents a method wherein energy from steam produced in the at least one remaining stage of the multiple stages is transferred to a condenser of another stage of the multiple stages (i.e. by the transfer of the steam itself into said condenser of another stage) for reuse across the multiple stages (Efrat: Figures 1A and 1B, paragraphs [0003]-[0004], [0007], and [0034]-[0035]).
With regard to claim 24: As discussed in the rejection of claim 1 above, the method modified Efrat comprises a step of c) operating the water treatment system by allowing feedwater to flow into the water treatment system and heating the feedwater, thus causing scale to form on the conditioning layer, wherein energy from steam produced by heating the feedwater in one stage 101 of the multiple stages is transferred to another stage 101 of the multiple stages for reuse across the multiple stages, i.e. by transferring steam that is produced in one stage to the interior of the tubes 110 in another stage 101 to be condensed therein, thus transferring heat from said steam to the stage in which it is condensed (Efrat: Figures 1A and 1B, paragraphs [0003]-[0004], [0007], and [0034]-[0035]). See rejection of claim 1 above for further details.
Thus, it is understood that modified Efrat represents a method wherein energy from steam produced in the at least one remaining stage of the multiple stages is produced by an evaporation chamber of the at least one remaining stage of the multiple stages is transferred to a condenser chamber of another stage of the multiple stages (i.e. by the transfer of the steam itself into said condenser chamber of another stage) for reuse across the multiple stages (Efrat: Figures 1A and 1B, paragraphs [0003]-[0004], [0007], and [0034]-[0035]).
Claims 12, 15, and 16 is/are rejected under 35 U.S.C. 103 as being unpatentable over Efrat in view of Efrat II, Bauer, and Sparrow as applied to claim 1 above, and in further view of Pottharst (US 3,236,748).
With regard to claim 12: In Modified Efrat, the step of removing the conditioning layer of the at least one bypassed stage further comprises mechanically weakening the scale through the use of thermal shock, wherein thermal shock comprises cooling the elements susceptible to scale formation causing the elements susceptible to scale formation to contract, inducing scale breakage (Efrat: paragraphs [0025]-[0027]).
Note: Efrat teaches that mechanical weakening may be carried out in addition to the cleaning by the chemical cleaner (paragraph [0023]-[0027]). Thus, in at least some embodiments of modified Efrat, both chemical cleaning and mechanical weakening are carried out. In the unlikely alternative, the aforementioned teachings of Efrat clearly suggest removing the conditioning layer and the scale by using both mechanical weakening and chemical cleaning, i.e. acid cleaning in modified Efrat.
In the unlikely event that such an embodiment were not already included within modified Efrat, it would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Efrat by removing conditioning layer and scale using both step mechanical weakening (i.e. by thermal shock) and acid cleaning, in order to obtain a method of scale removal in accordance with Efrat’s suggestion that conditioning layer and scale removal can be affected by a combination of mechanical weakening by thermal shock and acid cleaning.
Modified Efrat does not explicitly teach that the mechanical weakening includes both thermal shock and direct mechanical energy wherein direct mechanical energy comprises vibration, tapping, and/or sound.
However, use of such direct mechanical energy to clean scale from scale susceptible elements within water treatment systems (evaporators) is notoriously well known in the art. For example, Pottharst describes the use of ultrasonic vibrations for scale removal in an evaporator system as being conventional (Column 6 Lines 44-54). It is well established that it would be obvious to one of ordinary skill in the art to combine known prior art elements in order to obtain predictable results (see MPEP 2143).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Efrat in view of Pottharst by adding an element of mechanically weakening the scale through the use of direct mechanical energy (i.e. in addition to the thermal shock), wherein the direct mechanical energy comprises ultrasonic vibration, to the step of removing the conditioning layer, in order to obtain a predictably functional method wherein scale is thoroughly cleaned from the water treatment system through the combined application of acid treatment, thermal shock, and direct mechanical energy in the form of vibration.
With regard to claim 15: Modified Efrat is silent to the liquid mixture having a temperature lower than 10 °C.
However, a person having ordinary skill in the art would recognize the temperature of the liquid mixture used for cooling the elements in the mechanical weakening of the scale by thermal shock as being a result effective variable. Specifically, a person having ordinary skill in the art would recognize that the liquid mixture must be colder than the elements in order to cool said elements. Additionally, a person having ordinary skill in the art would recognize that the lower the temperature of the liquid mixture, the more quickly it will cool the cooling elements. It is understood that thermal shock is most effectively achieved when cooling is carried out very rapidly. Thus, for the purposes of inducing thermal shock for breaking the scale, a person having ordinary skill in the art would recognize that it would be advantageous to use a liquid mixture which is very cold, i.e. at a temperature significantly lower than that of the elements. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Efrat by optimizing the temperature of the liquid mixture used to cool the elements and induce thermal shock, i.e. by configuring said liquid mixture to have a temperature much colder than that of the elements, e.g. a temperature of 10 °C or lower, in order to obtain a liquid mixture which will rapidly cool the elements so as to effectively induce thermal shock for breaking the scale.
With regard to claim 16: Modified Efrat is silent to the liquid mixture having a temperature lower than -40 °C.
However, a person having ordinary skill in the art would recognize the temperature of the liquid mixture used for cooling the elements in the mechanical weakening of the scale by thermal shock as being a result effective variable. Specifically, a person having ordinary skill in the art would recognize that the liquid mixture must be colder than the elements in order to cool said elements. Additionally, a person having ordinary skill in the art would recognize that the lower the temperature of the liquid mixture, the more quickly it will cool the cooling elements. It is understood that thermal shock is most effectively achieved when cooling is carried out very rapidly. Thus, for the purposes of inducing thermal shock for breaking the scale, a person having ordinary skill in the art would recognize that it would be advantageous to use a liquid mixture which is very cold, i.e. at a temperature significantly lower than that of the elements. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Efrat by optimizing the temperature of the liquid mixture used to cool the elements and induce thermal shock, i.e. by configuring said liquid mixture to have a temperature much colder than that of the elements, e.g. a temperature of -40 °C or lower, in order to obtain a liquid mixture which will rapidly cool the elements so as to effectively induce thermal shock for breaking the scale.
Claims 13 and 14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Efrat in view of Efrat II, Bauer, Sparrow, and Pottharst as applied to claim 12 above, and further in view of chem.ucla.edu (“Cooling Baths”, http://www.chem.ucla.edu/research/org/MERLIC_GROUP/cooling_baths.html).
With regard to claim 13: Modified Efrat is silent to the liquid mixture comprising a solvent and dry ice and/or liquid nitrogen.
However, it is notoriously well known in the art to form cooling liquids using mixtures of solvents with dry ice or liquid nitrogen. For example, chem.ucla.edu provides a list of liquid mixtures for cooling, i.e. cooling baths, wherein many of the liquid mixtures comprise a solvent and dry ice (solid carbon dioxide) or a solvent and liquid nitrogen. Chem.ucla.edu indicates that said liquid mixtures (cooling baths) can achieve very cold temperatures. A person having ordinary skill in the art would recognize that the liquid mixture must be colder than the elements in order to cool said elements. Additionally, a person having ordinary skill in the art would recognize that the lower the temperature of the liquid mixture, the more quickly it will cool the cooling elements. It is understood that thermal shock is most effectively achieved when cooling is carried out very rapidly. Thus, a person having ordinary skill in the art would desire to use a mixture which is very cold as the liquid mixture in modified Efrat in order to rapidly cool the elements so as to effectively induce thermal shock for breaking the scale, and would expect that the liquid mixtures (cooling baths) taught by chem.ucla.edu would suffice.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Efrat in view of chem.ucla.edu by selecting one of the cooling bath mixtures taught by chem.ucla.edu, i.e. one comprising a solvent and dry ice and/or liquid nitrogen, for use as the liquid mixture in Efrat, in order to obtain a method having a very cold liquid mixture for cooling the elements rapidly so as to effectively induce thermal shock for breaking the scale.
With regard to claim 14: Modified Efrat is silent to the liquid mixture comprising ice and one or more salts in solution.
However, it is notoriously well known in the art to form cooling liquids using mixtures ice and salt in solution. For example, chem.ucla.edu provides a list of liquid mixtures for cooling, i.e. cooling baths, wherein one of the mixtures is comprised of ice and salt in solution (note: Although said mixture is described merely as being a mixture of ice and salt, it is understood that said mixture includes salt in solution, i.e. with liquid water, as said mixture would not constitute a “cooling bath” unless said salt were in the form of a liquid solution. Chem.ucla.edu indicates that said liquid mixtures (cooling baths) can achieve very cold temperatures. A person having ordinary skill in the art would recognize that the liquid mixture must be colder than the elements in order to cool said elements. Additionally, a person having ordinary skill in the art would recognize that the lower the temperature of the liquid mixture, the more quickly it will cool the cooling elements. It is understood that thermal shock is most effectively achieved when cooling is carried out very rapidly. Thus, a person having ordinary skill in the art would desire to use a mixture which is very cold as the liquid mixture in modified Efrat in order to rapidly cool the elements so as to effectively induce thermal shock for breaking the scale, and would expect that the liquid mixtures (cooling baths) taught by chem.ucla.edu would suffice.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Efrat in view of chem.ucla.edu by selecting one of the cooling bath mixtures taught by chem.ucla.edu, i.e. one comprising ice and salt in solution, for use as the liquid mixture in Efrat, in order to obtain a method having a very cold liquid mixture for cooling the elements rapidly so as to effectively induce thermal shock for breaking the scale.
Claims 25 and 26 is/are rejected under 35 U.S.C. 103 as being unpatentable over Efrat in view of Efrat II, Bauer, and Sparrow as applied to claim 1 above, and in further view of Geesen (US 4,224,036)
With regard to claims 25 and 26: Modified Efrat does not explicitly teach that each stage of the multiple stages has a different temperature, wherein a temperature of the first stage of the multiple stages is higher than each remaining stage of the multiple stages.
Examiner notes that temperature(s) of each evaporator stage is merely a matter of intended use/manner of operating. Statements of intended use/manner of operating do not distinguish apparatus claims from prior art apparatus that are capable of use/operation in the claimed manner (see MPEP 2114).
Regardless, it is notoriously well-known that multi-stage evaporators of the multi-effect evaporator type are operated with each stage of the multiple stages has a different temperature, wherein a temperature of the first stage of the multiple stages is higher than each remaining stage of the multiple stages. For example, Geesen teaches a multi-effect evaporator system wherein each evaporator stage (effect) is operated at a different temperature, and wherein the temperature of the first stage (effect) is higher than each remaining stage (Figure 3, Column 9). Multi-effect evaporator systems are operated with such a temperature profile in order to allow waste energy from one stage to be transferred to the next in order to use said waste energy to evaporate water in said next stage. A person having an understanding of heat transfer will recognize that heat flows from areas of high temperature to areas of low temperature. Thus, in order to obtain a multi-effect evaporator system that is actually capable of transferring waste heat from upstream stages to downstream stages, said stages must each be operated at different temperatures, with downstream stages being operated at lower temperatures than upstream stages.
In the unlikely event that is were not already the case in base Efrat, it would have been obvious to one of ordinary skill in the art to further modify Efrat in view of Geesen by configuring the water treatment system (multi-effect evaporator of modified Efrat to operate such that each (effect) stage of the multiple stages has a different temperature, wherein a temperature of the first (effect) stage of the multiple stages is higher than each remaining stage of the multiple stages, in order to obtain a multi-effect evaporator system which is capable of transferring waste heat from upstream stages to downstream stages.
Claims 19, 17, and 18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Efrat in view of Efrat II, Bauer, Sparrow, and Hart et al. (“Application of Carbon Dioxide to Reduce Water-Side Lime Scale in Heat Exchangers”), hereafter referred to as Hart.
With regard to claim 19: Efrat teaches a method of cleaning a water treatment system (abstract), the method comprising:
a) providing a water treatment system (evaporator) having elements (heat transfer pipes) susceptible to scale formation during operation of the water treatment system (abstract, paragraph [0034]).
Efrat teaches that “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added). The evaporators in Figures 1A and 1B are water treatment systems (multi-effect evaporator) 100 comprising multiple stages (effects) 101, each of stage 101 of the multiple stages having elements (heat transfer pipes/tubes) 110 susceptible to scale formation during operation of the water treatment system, each stage 101 of the multiple stages fluidly connected to one another, and each stage of the multiple stages comprising a condenser chamber (inner portion of tubes 110) and an evaporation chamber (chamber surrounding the outer portion of tubes 110) (Figures 1A and 1B, paragraphs [0003]-[0004] and [0007]). By teaching that the “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added), Efrat is disclosing embodiments comprising a step of providing a water treatment system wherein the water treatment system is the water treatment system of Figure 1A or Figure 1B.
Thus, Efrat teaches (i.e. anticipates) a step of a) providing a water treatment system (multi-effect evaporator) 100 comprising multiple stages (effects) 101, each of stage 101 of the multiple stages having elements (heat transfer pipes/tubes) 110 susceptible to scale formation during operation of the water treatment system 100, each stage 101 of the multiple stages fluidly connected to one another, and each stage of the multiple stages comprising a condenser chamber (inner portion of tubes 110) and an evaporation chamber (chamber surrounding the outer portion of tubes 110) (Figures 1A and 1B, paragraphs [0003]-[0004], [0007], and [0034]).
In the unlikely alternative, Efrat’s teaching that the “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added), would serve as a strong suggestion that Efrat’s method be carried out on the systems of Figure 1A and/or Figure 1B. Efrat teaches that “scale formation on heat transfer surfaces remains one of the most severe problems in the design and operation of multiple-effect distillers for seawater desalination, having a highly deleterious effect on the specific energy consumption and production capacity,” (paragraph [0007]), thus providing clear indication that the systems of Figures 1A and 1B would benefit from Efrat’s method being carried out on said systems.
In the unlikely event that it were not already the case in base Efrat, it would have been obvious to one of ordinary skill in the art to modify Efrat by carrying out the method of Efrat on the water treatment system of Figure 1A and/or the water treatment system of Figure 1B, i.e. such that Efrat were to comprise a step of a) providing a water treatment system (multi-effect evaporator) 100 comprising multiple stages (effects) 101, each of stage 101 of the multiple stages having elements (heat transfer pipes/tubes) 110 susceptible to scale formation during operation of the water treatment system 100, each stage 101 of the multiple stages fluidly connected to one another, and each stage of the multiple stages comprising a condenser chamber (inner portion of tubes 110) and an evaporation chamber (chamber surrounding the outer portion of tubes 110), in order to obtain a predictably functional method which is: 1) congruent with Efrat’s express suggestions (i.e. those in paragraph [0034]), and 2) beneficial to the water treatment system, i.e. the water treatment system of Figure 1A and/or Figure 1B, as indicated by the teachings of paragraph [0007]).
Efrat’s method of cleaning a water treatment system further comprises: b) depositing a conditioning layer (sacrificial layer) from an aqueous solution onto at least some of the elements (heat transfer pipes) susceptible to scale formation by chemical treatment comprising adding a base to the aqueous solution to increase the pH of the aqueous solution (abstract, paragraphs [0017], [0020], [0034], and [0036]-[0037]). Note: Although the addition of a base in said chemical treatment is not explicitly taught, it is implicit, as in order to raise pH, a base must be added.
Efrat teaches that “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added). The evaporators in Figures 1A and 1B are water treatment systems (multi-effect evaporator) 100 comprising multiple stages (effects) 101, each of stage 101 of the multiple stages having elements (heat transfer pipes/tubes) 110 susceptible to scale formation during operation of the water treatment system, each stage 101 of the multiple stages fluidly connected to one another, and each stage of the multiple stages comprising a condenser chamber (inner portion of tubes 110) and an evaporation chamber (chamber surrounding the outer portion of tubes 110) (Figures 1A and 1B, paragraphs [0003]-[0004] and [0007]). By teaching that the “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added), Efrat is disclosing embodiments comprising a step of providing a water treatment system wherein the water treatment system is the water treatment system of Figure 1A or Figure 1B.
Thus, Efrat teaches (i.e. anticipates) a step of b) depositing a conditioning layer (sacrificial layer) onto at least some of the elements (heat transfer pipes/tubes) 110 susceptible to scale formation by a by chemical treatment comprising adding a base to the aqueous solution to increase the pH of the aqueous solution (Figures 1A and 1B, paragraphs [0003]-[0004], [0017], [0020], [0034], and [0036]-[0037]). Note: Although the addition of a base in said chemical treatment is not explicitly taught, it is implicit, as in order to raise pH, a base must be added.
In the unlikely alternative, Efrat’s teaching that the “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added), would serve as a strong suggestion that Efrat’s method be carried out on the systems of Figure 1A and/or Figure 1B. Efrat teaches that “scale formation on heat transfer surfaces remains one of the most severe problems in the design and operation of multiple-effect distillers for seawater desalination, having a highly deleterious effect on the specific energy consumption and production capacity,” (paragraph [0007]), thus providing clear indication that the systems of Figures 1A and 1B would benefit from Efrat’s method being carried out on said systems.
In the unlikely event that it were not already the case in base Efrat, it would have been obvious to one of ordinary skill in the art to modify Efrat by carrying out the method of Efrat on the water treatment system of Figure 1A and/or the water treatment system of Figure 1B, i.e. such that Efrat were to comprise a step of b) depositing a conditioning layer (sacrificial layer) onto at least some of the elements (heat transfer pipes/tubes) 110 susceptible to scale formation by a by chemical treatment comprising adding a base to the aqueous solution to increase the pH of the aqueous solution, in order to obtain a predictably functional method which is: 1) congruent with Efrat’s express suggestions (i.e. those in paragraph [0034]), and 2) beneficial to the water treatment system, i.e. the water treatment system of Figure 1A and/or Figure 1B, as indicated by the teachings of paragraph [0007]).
Efrat’s method of cleaning a water treatment system further comprises: c) operating the water treatment system (evaporator) by allowing feedwater to flow into the water treatment system and heating the feedwater, thus causing scale to form on the conditioning layer (sacrificial layer) (abstract, paragraph [0035]).
Efrat teaches that “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added). The evaporators in Figures 1A and 1B are water treatment systems (multi-effect evaporator) 100 comprising multiple stages (effects) 101, each of stage 101 of the multiple stages having elements (heat transfer pipes/tubes) 110 susceptible to scale formation during operation of the water treatment system, each stage 101 of the multiple stages fluidly connected to one another, and each stage of the multiple stages comprising a condenser chamber (inner portion of tubes 110) and an evaporation chamber (chamber surrounding the outer portion of tubes 110) (Figures 1A and 1B, paragraphs [0003]-[0004] and [0007]), wherein in operation of said systems 100, energy from steam produced by heating the feedwater in one stage 101 of the multiple stages is transferred to another stage 101 of the multiple stages for reuse across the multiple stages, i.e. by transferring steam that is produced in one stage to the interior of the tubes 110 in another stage 101 to be condensed therein, thus transferring heat from said steam to the stage in which it is condensed (Figures 1A and 1B, paragraphs [0003]-[0004]). By teaching that the “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added), Efrat is disclosing embodiments comprising a step of providing a water treatment system wherein the water treatment system is the water treatment system of Figure 1A or Figure 1B.
Thus, Efrat teaches (i.e. anticipates) a step of c) operating the water treatment system by allowing feedwater to flow into the water treatment system and heating the feedwater, thus causing scale to form on the conditioning layer, wherein energy from steam produced by heating the feedwater in one stage 101 of the multiple stages is transferred to another stage 101 of the multiple stages for reuse across the multiple stages, i.e. by transferring steam that is produced in one stage to the interior of the tubes 110 in another stage 101 to be condensed therein, thus transferring heat from said steam to the stage in which it is condensed (Figures 1A and 1B, paragraphs [0003]-[0004], [0007], and [0034]-[0035]).
In the unlikely alternative, Efrat’s teaching that the “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added), would serve as a strong suggestion that Efrat’s method be carried out on the systems of Figure 1A and/or Figure 1B. Efrat teaches that “scale formation on heat transfer surfaces remains one of the most severe problems in the design and operation of multiple-effect distillers for seawater desalination, having a highly deleterious effect on the specific energy consumption and production capacity,” (paragraph [0007]), thus providing clear indication that the systems of Figures 1A and 1B would benefit from Efrat’s method being carried out on said systems.
In the unlikely event that it were not already the case in base Efrat, it would have been obvious to one of ordinary skill in the art to modify Efrat by carrying out the method of Efrat on the water treatment system of Figure 1A and/or the water treatment system of Figure 1B, i.e. such that Efrat were to comprise a step of c) operating the water treatment system by allowing feedwater to flow into the water treatment system and heating the feedwater, thus causing scale to form on the conditioning layer, wherein energy from steam produced by heating the feedwater in one stage 101 of the multiple stages is transferred to another stage 101 of the multiple stages for reuse across the multiple stages, i.e. by transferring steam that is produced in one stage to the interior of the tubes 110 in another stage 101 to be condensed therein, thus transferring heat from said steam to the stage in which it is condensed, in order to obtain a predictably functional method which is: 1) congruent with Efrat’s express suggestions (i.e. those in paragraph [0034]), and 2) beneficial to the water treatment system, i.e. the water treatment system of Figure 1A and/or Figure 1B, as indicated by the teachings of paragraph [0007]).
Efrat’s method of cleaning a water treatment system further comprises: d) removing the conditioning layer (sacrificial layer), thus also removing the scale (abstract, paragraph [0035]), wherein the removal of the conditioning layer is accomplished through the use of a chemical cleaner (paragraph [0023], claim 13).
Efrat teaches that “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added). The evaporators in Figures 1A and 1B are water treatment systems (multi-effect evaporator) 100 comprising multiple stages (effects) 101, each of stage 101 of the multiple stages having elements (heat transfer pipes/tubes) 110 susceptible to scale formation during operation of the water treatment system, each stage 101 of the multiple stages fluidly connected to one another, and each stage of the multiple stages comprising a condenser chamber (inner portion of tubes 110) and an evaporation chamber (chamber surrounding the outer portion of tubes 110) (Figures 1A and 1B, paragraphs [0003]-[0004] and [0007]), wherein in operation of said systems 100, energy from steam produced by heating the feedwater in one stage 101 of the multiple stages is transferred to another stage 101 of the multiple stages for reuse across the multiple stages, i.e. by transferring steam that is produced in one stage to the interior of the tubes 110 in another stage 101 to be condensed therein, thus transferring heat from said steam to the stage in which it is condensed (Figures 1A and 1B, paragraphs [0003]-[0004]). By teaching that the “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added), Efrat is disclosing embodiments comprising a step of providing a water treatment system wherein the water treatment system is the water treatment system of Figure 1A or Figure 1B.
Thus, Efrat teaches (i.e. anticipates) a step of d) removing the conditioning layer (sacrificial layer), thus also removing the scale, wherein the removal of the conditioning layer is accomplished through the use of a chemical cleaner, wherein said step d) is carried out on/in the water treatment system of Figure 1A and/or Figure 1B (Figures 1A and 1B, paragraphs [0003]-[0004], [0007], 0023], and [0034]-[0035], claim 13).
In the unlikely alternative, Efrat’s teaching that the “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added), would serve as a strong suggestion that Efrat’s method be carried out on the systems of Figure 1A and/or Figure 1B. Efrat teaches that “scale formation on heat transfer surfaces remains one of the most severe problems in the design and operation of multiple-effect distillers for seawater desalination, having a highly deleterious effect on the specific energy consumption and production capacity,” (paragraph [0007]), thus providing clear indication that the systems of Figures 1A and 1B would benefit from Efrat’s method being carried out on said systems.
In the unlikely event that it were not already the case in base Efrat, it would have been obvious to one of ordinary skill in the art to modify Efrat by carrying out the method of Efrat on the water treatment system of Figure 1A and/or the water treatment system of Figure 1B, i.e. such that Efrat were to comprise a step of d) removing the conditioning layer (sacrificial layer), thus also removing the scale, wherein the removal of the conditioning layer is accomplished through the use of a chemical cleaner, wherein said step d) is carried out on/in the water treatment system of Figure 1A and/or Figure 1B, in order to obtain a predictably functional method which is: 1) congruent with Efrat’s express suggestions (i.e. those in paragraph [0034]), and 2) beneficial to the water treatment system, i.e. the water treatment system of Figure 1A and/or Figure 1B, as indicated by the teachings of paragraph [0007]).
In Efrat, the conditioning layer may be calcium carbonate (CaCO3) (paragraphs [0034], [0041], and [0042]).
Efrat is silent to step d) comprising bypassing at least one stage of the multiple stages using a first series of valves to redirect the feedwater and a second series of valves to redirect energy from steam and removing the CaCO3 conditioning layer of the at least one stage of the multiple stages that has been bypassed through use of one or more acids, thus also removing the scale of the at least one stage of the multiple stages that has been bypassed, while maintaining a transfer of the redirected energy from steam, wherein the redirected enemy from steam is redirected energy from steam of at least one remaining stage of the multiple stages for reuse across another remaining stage of the multiple stages, thereby preventing a complete shutdown of the water treatment system.
However, bypassing during operations of cleaning scale from multi-stage evaporators is known in the art. For example, Efrat II teaches a method of operating a multistage evaporator system in a cleaning mode, wherein at least one stage of a plurality of stages is bypassed (physically separated) using a series of valves, and the at least one stage that has been bypassed is treated with a cleaning agent so as to remove scale from the at least one stage that has been bypassed during operation of the multistage evaporator system, while maintaining a transfer of energy from steam of at least one remaining stage of the plurality of stages for reuse across the at least one remaining stage, thereby preventing a complete shutdown of the system (abstract, Figure 1, paragraphs [0037]-[0040]). A person having ordinary skill in the art would recognize that the ability to clean a single stage while keeping the remainder of the evaporator system (i.e. outside of the stage being cleaned) in operation is advantageous, as it allows for cleaning to be carried out with minimal disruption to the evaporator’s productivity.
It is acknowledged that Efrat II does not teach bypassing an intermediate stage (i.e. by redirecting energy from steam originating from a remaining stage of the multiple stages while maintaining a transfer of the redirected energy from steam originating from the remaining stage the multiple stages for reuse across another remaining stage of the multiple stages). Instead Efrat II only teaches bypassing a first stage, or a first group of stages. It is acknowledged that Efrat II does not teach the use of a both a first set of valves to reroute feedwater and a second set of valves to reroute steam.
However, bypass arrangements for bypassing an intermediate stage (i.e. by redirecting energy from steam originating from a remaining stage of the multiple stages while maintaining a transfer of the redirected energy from steam originating from the remaining stage the multiple stages for reuse across another remaining stage of the multiple stages) are known in the art. It is further known in the art for such bypass arrangements to make use of a first set of valve to redirect feed liquid and a second set of valves to redirect energy from steam.
For example, Bauer expressly teaches a process of operating a multiple effect evaporator system wherein: a series of valves 34, 35, and 41 is used to redirect steam from a first evaporator stage (pan) C through pipe 40, away from a middle stage B, and onward to a final stage A (Figure 2, Page 3 Line 110-Page 4 Line 17); and another series of valves 20’, 50, 51 is used to redirect feed liquid from the first evaporator stage C through valve 51, away from the middle stage B, and onward to the final stage A (Figure 2, Page 3 Line 110-Page 4 Line 17). Applicant’s attention is further directed to the disclosure of Page 2 Line 93-Page 3 Line 5.
A person having ordinary skill in the art would recognize that it would be advantageous to bypass specifically an intermediate stage for the purposes of cleaning said intermediate stage as opposed to merely a first stage or a first group of stages (as is done in Efrat II), as bypassing an intermediate stage will allow specifically the intermediate stage to be cleaned on its own without shutting down all of the evaporator stages or an entire first group of evaporator stages. Indeed, Bauer provides express indication that the middle stage (pan) B can be bypassed for the purposes of cleaning said stage without shutting down the first and final stages C and A (Page 3 Lines 112-116).
With respect to the use of both a first serries of valves and a second series of valves, a person having ordinary skill in the art would recognize that having both a first and second serries of valves would be advantageous, if not absolutely necessary, as it is understood that, in the context of multi-effect evaporator systems, product steam (and thus the energy therein) and feedwater are separate flows which should not be combined into a single flow. Therefore, when considering bypass arrangements for a multi-effect evaporator system, a person having ordinary skill in the art would find the use of first and second sets of valves desirable in order to enable both steam and feedwater flows to bypass a particular stage.
It would have been obvious to one of ordinary skill in the art before the effective filing date to modify Efrat in view of Efrat II and Bauer by carrying out the step of removing the conditioning layer, and thus the scale, as a step of d) bypassing at least one stage of the multiple stages using a first series of valves to redirect the feedwater and a second series of valves to redirect energy from steam and removing the conditioning layer of the at least one stage of the multiple stages that has been bypassed through use of one or more acids during the operation of the water treatment system, thus also removing the scale of the at least one stage of the multiple stages that has been bypassed, while maintaining a transfer of the redirected energy from steam, wherein the redirected energy from steam is redirected energy from steam of at least one remaining stage of the multiple stages for reuse across another remaining stage of the multiple stages, thereby preventing a complete shutdown of the water treatment system, in order to obtain a method wherein: i) both steam and feedwater flows can be made to bypass a particular stage, and ii) scale can be removed from an intermediate stage of the multiple stages without shutting down all of the evaporator stages or an entire first group of evaporator stages, such that scale can be removed from the intermediate stage of the water treatment system (evaporator) with minimal disruption to the evaporator’s productivity.
It would have been obvious to one of ordinary skill in the art before the effective filing date to modify Efrat in view of Efrat II and Bauer by carrying out the step of removing the CaCO3 conditioning layer, and thus the scale, as a step of step d) bypassing at least one stage of the multiple stages using a first series of valves to redirect the feedwater and a second series of valves to redirect energy from steam and removing the CaCO3 conditioning layer of the at least one stage of the multiple stages that has been bypassed through use of one or more acids, thus also removing the scale of the at least one stage of the multiple stages that has been bypassed, while maintaining a transfer of the redirected energy from steam, wherein the redirected enemy from steam is redirected energy from steam of at least one remaining stage of the multiple stages for reuse across another remaining stage of the multiple stages, thereby preventing a complete shutdown of the water treatment system, in order to obtain a method wherein: i) both steam and feedwater flows can be made to bypass a particular stage, and ii) scale can be removed from an intermediate stage of the multiple stages without shutting down all of the evaporator stages or an entire first group of evaporator stages, such that scale can be removed from the intermediate stage of the water treatment system (evaporator) with minimal disruption to the evaporator’s productivity.
Modified Efrat does not explicitly teach that the chemical cleaner comprises one or more acids.
However, Efrat does not identify any specific examples of chemical cleaners. Thus, a person having ordinary skill in the art would look elsewhere to find examples of suitable chemical cleaners.
It is notoriously well known in the art to remove scale using acid-based cleaners. For example, Sparrow teaches a method for concentrating a solution using evaporation (Abstract, Paragraph [0001]), the method comprising the use of a “clean-in-place” solution having descaling capability, wherein the clean in place solution may comprise an acid (paragraph [0064] and [0140]). Notably, Sparrow teaches that “dilute citric acid may be used to de-scale calcium carbonate,” (paragraph [0140]), clearly indicating that citric acid solutions are suitable for removing calcium carbonate scaling. Efrat teaches that the conditioning layer (sacrificial layer) may be calcium carbonate (paragraphs [0034], [0041], and [0042]). Thus, in view of the combined teachings of Efrat and Sparrow, a person having ordinary skill in the art would have a reasonable expectation that an acid cleaning solution, e.g. a citric acid solution, could be used as the chemical cleaner for removing the conditioning layer (sacrificial layer) in Efrat.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Efrat in view of Sparrow by using an acid-based cleaning solution, i.e. a solution comprising one or more acids, as the chemical cleaner for removing the conditioning layer, and thus the scale, in Efrat, in order to obtain a predictably successful method of removing scale in accordance with the teachings of Efrat.
Modified Efrat does not explicitly teach that the step of depositing a CaCO3 layer comprises adding carbon dioxide that is absorbed in the aqueous solution.
However, to an individual having ordinary skill in the art of chemistry, the teachings of Efrat would suggest a depositing step which involves the addition of CO2.
As discussed above, Efrat teaches a step of depositing a conditioning layer (sacrificial layer) from an aqueous solution onto at least some of the elements (heat transfer pipes) susceptible to scale formation by chemical treatment comprising adding a base to the aqueous solution to increase the pH of the aqueous solution (abstract, paragraphs [0017], [0020], [0034], and [0036]-[0037]). Furthermore, In Efrat, the conditioning layer may be calcium carbonate (CaCO3) (paragraphs [0034], [0041], and [0042]). Thus, Efrat clearly teaches, or at least suggests, depositing a calcium carbonate conditioning layer from an aqueous solution (i.e. a solution of calcium carbonate in water) onto at least some of the elements susceptible to scale formation by a chemical treatment comprising adding a base to the aqueous solution to increase the pH of the aqueous solution.
A person having ordinary skill in the art of chemistry will recognize the following facts above calcium carbonate:
First, the solubility of calcium carbonate is water is highly dependent on the pH of the solution. The higher the pH of the solution, the lower the solubility of calcium carbonate therein. As evidence, Examiner points to Hart (see section titled “Chemistry of the System” and Figure 1).
Second, when dissolved in water, calcium carbonate will interact with carbon dioxide in an equilibrium reaction to form calcium bicarbonate. As evidence, Examiner points to Hart (see section titled “Chemistry of the System”).
Third, the concentration of calcium bicarbonate resulting from said equilibrium reaction is at its maximum at a pH of 8.3. As evidence, Examiner points to Hart (see section titled “Chemistry of the System”). Thus, it is understood that increasing the pH of an aqueous solution comprising calcium bicarbonate above 8.3 will necessarily shift the equilibrium reaction away from calcium bicarbonate, causing at least a portion of said calcium bicarbonate to break down into calcium carbonate and CO2.
Again, as discussed above, Efrat clearly teaches, or at least suggests, depositing a calcium carbonate conditioning layer from an aqueous solution (i.e. a solution of calcium carbonate in water) onto at least some of the elements susceptible to scale formation by a chemical treatment comprising adding a base to the aqueous solution to increase the pH of the aqueous solution. As discussed above, aqueous calcium carbonate will interact with carbon dioxide in an equilibrium reaction to form calcium bicarbonate. Therefore, the aqueous solution in the (i.e. the solution of calcium carbonate in water), as taught or at least suggested by Efrat, is understood to comprise calcium bicarbonate.
Efrat explicitly teaches increasing the pH of the aqueous solution to a level of 9 or above (paragraphs [0017] and [0037]). As discussed above, increasing the pH of an aqueous solution comprising calcium bicarbonate above 8.3 will necessarily shift the equilibrium reaction away from calcium bicarbonate, causing at least a portion of said calcium bicarbonate to break down into calcium carbonate and CO2. Therefore, in depositing step, as taught or at least suggested by Efrat, the addition of the base will necessarily lead to the breakdown of a portion of calcium bicarbonate in the aqueous solution into calcium carbonate and CO2 and thus, will lead to the addition of CO2 gas, at least some of which is absorbed into the aqueous solution.
At the very least, the teachings of Efrat, in combination with chemical knowledge obtained from Hart, would at least suggest to one of ordinary skill in the art a step of depositing a calcium carbonate conditioning layer from an aqueous solution (i.e. a solution of calcium carbonate in water) onto at least some of the elements susceptible to scale formation by a chemical treatment comprising adding a base to the aqueous solution to increase the pH of the aqueous solution and adding CO2 gas, i.e. as a result of breakdown of bicarbonate caused by the pH increase, wherein at least some of said CO2 gas is absorbed into the aqueous solution.
Assuming it not implicit within Efrat, it would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Efrat in view of Hart by carrying out the step of depositing the conditioning layer as a step of depositing a calcium carbonate conditioning layer from an aqueous solution (i.e. a solution of calcium carbonate in water) onto at least some of the elements susceptible to scale formation by a chemical treatment comprising adding a base to the aqueous solution to increase the pH of the aqueous solution and adding CO2 gas, i.e. as a result of breakdown of bicarbonate caused by the pH increase, wherein at least some of said CO2 gas is absorbed into the aqueous solution, in order to obtain a predictably functional depositing step which is congruent with the teachings of Efrat.
With regard to claims 17 and 18: Modified Efrat is silent to a step c’’ after step c and before step d, wherein step c’’ comprises fully draining the feedwater from the water treatment system; and to a step c’’’ after step c’’ and before step d, wherein step c’’’ comprises drying the elements susceptible to scale formation.
However, as discussed in the rejection of claim 16 above, modified Efrat involves cooling the elements with a liquid mixture having a temperature of less than -40 °C. Said temperature is well below the normal freezing point of water. Thus, a person having ordinary skill in the art would recognize that steps c’’ and c’’’ would be necessary in modified Efrat, as without such steps, the feed water in Efrat would certainly freeze around/onto the elements during the cooling thereof with the liquid mixture. Such freezing of the feed water could cause damage to the water treatment system, and would at least interfere with descaling operations.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Efrat by adding a step c’’ after step c and before step d, wherein step c’’ comprises fully draining the feedwater from the water treatment system, and by adding a step c’’’ after step c’’ and before step d, wherein step c’’’ comprises drying the elements susceptible to scale formation, in order to prevent feedwater from freezing around or onto the elements during the cooling thereof with the liquid mixture.
Claims 22 is/are rejected under 35 U.S.C. 103 as being unpatentable over Efrat in view of Efrat II, Bauer, Sparrow, and Pottharst.
With regard to claim 22: Efrat teaches a method of cleaning a water treatment system (abstract), the method comprising:
a) providing a water treatment system (evaporator) having elements (heat transfer pipes) susceptible to scale formation during operation of the water treatment system (abstract, paragraph [0034]).
Efrat teaches that “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added). The evaporators in Figures 1A and 1B are water treatment systems (multi-effect evaporator) 100 comprising multiple stages (effects) 101, each of stage 101 of the multiple stages having elements (heat transfer pipes/tubes) 110 susceptible to scale formation during operation of the water treatment system, each stage 101 of the multiple stages fluidly connected to one another, and each stage of the multiple stages comprising a condenser chamber (inner portion of tubes 110) and an evaporation chamber (chamber surrounding the outer portion of tubes 110) (Figures 1A and 1B, paragraphs [0003]-[0004] and [0007]). By teaching that the “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added), Efrat is disclosing embodiments comprising a step of providing a water treatment system wherein the water treatment system is the water treatment system of Figure 1A or Figure 1B.
Thus, Efrat teaches (i.e. anticipates) a step of a) providing a water treatment system (multi-effect evaporator) 100 comprising multiple stages (effects) 101 with steam energy recovery (i.e. through the transfer of steam generated to one stage to a following stage for condensation therein), each of stage 101 of the multiple stages having elements (heat transfer pipes/tubes) 110 susceptible to scale formation during operation of the water treatment system 100 (Figures 1A and 1B, paragraphs [0003]-[0004], [0007], and [0034]).
In the unlikely alternative, Efrat’s teaching that the “the present invention provides an improved method for affecting cleaning of heat transfer pipes within an evaporator, such as those used in seawater desalination plants and shown in FIGS. 1A and 1B,” (paragraph [0034], emphasis added), would serve as a strong suggestion that Efrat’s method be carried out on the systems of Figure 1A and/or Figure 1B. Efrat teaches that “scale formation on heat transfer surfaces remains one of the most severe problems in the design and operation of multiple-effect distillers for seawater desalination, having a highly deleterious effect on the specific energy consumption and production capacity,” (paragraph [0007]), thus providing clear indication that the systems of Figures 1A and 1B would benefit from Efrat’s method being carried out on said systems.
In the unlikely event that it were not already the case in base Efrat, it would have been obvious to one of ordinary skill in the art to modify Efrat by carrying out the method of Efrat on the water treatment system of Figure 1A and/or the water treatment system of Figure 1B, i.e. such that Efrat were to comprise a step of a) providing a water treatment system (multi-effect evaporator) 100 comprising multiple stages (effects) 101 with steam energy recovery (i.e. through the transfer of steam generated to one stage to a following stage for condensation therein), each of stage 101 of the multiple stages having elements (heat transfer pipes/tubes) 110 susceptible to scale formation during operation of the water treatment system 100, in order to obtain a predictably functional method which is: 1) congruent with Efrat’s express suggestions (i.e. those in paragraph [0034]), and 2) beneficial to the water treatment system, i.e. the water treatment system of Figure 1A and/or Figure 1B, as indicated by the teachings of paragraph [0007]).
b) depositing a conditioning layer (sacrificial layer) onto at least some of the elements (heat transfer pipes) susceptible to scale formation (abstract, paragraph [0034]).
c) operating the water treatment system (evaporator) by allowing feedwater to flow into the water treatment system and heating the feedwater, thus causing scale to form on the conditioning layer (sacrificial layer) (abstract, paragraph [0035]).
d) mechanically weakening the scale through the use of thermal shock, wherein thermal shock comprises cooling the elements susceptible to scale formation causing the elements susceptible to scale formation to contract, inducing scale breakage (Efrat: paragraphs [0025]-[0027]).
e) removing the conditioning layer (sacrificial layer), thus also removing the scale (abstract, paragraph [0035]), wherein the removal of the conditioning layer is accomplished through the use of a chemical cleaner (paragraph [0023], claim 13).
Note: Efrat teaches that mechanical weakening may be carried out in addition to the cleaning by the chemical cleaner (paragraph [0023]-[0027]). Thus, in at least some embodiments of Efrat, both chemical cleaning and mechanical weakening are carried out. In the unlikely alternative, the aforementioned teachings of Efrat clearly suggest removing the conditioning layer and the scale by using both mechanical weakening and chemical cleaning, i.e. acid cleaning in modified Efrat.
In the unlikely event that such an embodiment were not already included within Efrat, it would have been obvious to one of ordinary skill in the art before the effective filing date to modify Efrat by removing conditioning layer and scale using both step mechanical weakening (i.e. by thermal shock) and chemical cleaning, in order to obtain a method of scale removal in accordance with Efrat’s suggestion that conditioning layer and scale removal can be affected by a combination of mechanical weakening by thermal shock and chemical cleaning.
Efrat is silent to step e) comprising bypassing a stage of the multiple stages of the water treatment system using a first series of valves to redirect the feedwater and a second series of valves to redirect energy from steam wherein the feedwater and the energy from steam separately travel between the multiple stages and removing the conditioning layer through the use of one or more acids in the stage of the multiple stages of the water treatment system that has been bypassed during the operation of one or more remaining stages of the multiple stages of the water treatment system, thus also removing the scale in the stage of the multiple stages of the water treatment system that has been bypassed without a complete shutdown of the water treatment system.
However, bypassing during operations of cleaning scale from multi-stage evaporators is known in the art. For example, Efrat II teaches a method of operating a multistage evaporator system in a cleaning mode, wherein at least one stage of a plurality of stages is bypassed (physically separated) using a series of valves, and the at least one stage that has been bypassed is treated with a cleaning agent so as to remove scale from the at least one stage that has been bypassed during operation of the multistage evaporator system, while maintaining a transfer of energy from steam of at least one remaining stage of the plurality of stages for reuse across the at least one remaining stage, thereby preventing a complete shutdown of the system (abstract, Figure 1, paragraphs [0037]-[0040]). A person having ordinary skill in the art would recognize that the ability to clean a single stage while keeping the remainder of the evaporator system (i.e. outside of the stage being cleaned) in operation is advantageous, as it allows for cleaning to be carried out with minimal disruption to the evaporator’s productivity.
It is acknowledged that Efrat II does not explicitly teach the use of a both a first set of valves to reroute feedwater and a second set of valves to reroute steam; wherein the feedwater and the steam travel separately between the multiple stages
However, bypass arrangements that make use of a first set of valves to redirect feed liquid and a second set of valves to redirect energy from steam, wherein the feedwater and the steam travel separately between multiple stages, are known in the art.
For example, Bauer expressly teaches a process of operating a multiple effect evaporator system wherein: a series of valves 34, 35, and 41 is used to redirect steam from a first evaporator stage (pan) C through pipe 40, away from a middle stage B, and onward to a final stage A (Figure 2, Page 3 Line 110-Page 4 Line 17); and another series of valves 20’, 50, 51 is used to redirect feed liquid from the first evaporator stage C through valve 51, away from the middle stage B, and onward to the final stage A (Figure 2, Page 3 Line 110-Page 4 Line 17). Applicant’s attention is further directed to the disclosure of Page 2 Line 93-Page 3 Line 5.
A person having ordinary skill in the art would recognize that it would be advantageous to bypass specifically an intermediate stage for the purposes of cleaning said intermediate stage as opposed to merely a first stage or a first group of stages (as is done in Efrat II), as bypassing an intermediate stage will allow specifically the intermediate stage to be cleaned on its own without shutting down all of the evaporator stages or an entire first group of evaporator stages. Indeed, Bauer provides express indication that the middle stage (pan) B can be bypassed for the purposes of cleaning said stage without shutting down the first and final stages C and A (Page 3 Lines 112-116).
With respect to the use of both a first serries of valves and a second series of valves, a person having ordinary skill in the art would recognize that having both a first and second serries of valves would be advantageous, if not absolutely necessary, as it is understood that, in the context of multi-effect evaporator systems, product steam (and thus the energy therein) and feedwater are separate flows which should not be combined into a single flow. Therefore, when considering bypass arrangements for a multi-effect evaporator system, a person having ordinary skill in the art would find the use of first and second sets of valves desirable in order to enable both steam and feedwater flows to bypass a particular stage.
It would have been obvious to one of ordinary skill in the art before the effective filing date to modify Efrat in view of Efrat II and Bauer by carrying out the step of removing the conditioning layer, and thus the scale, as a step of e) bypassing a stage of the multiple stages of the water treatment system using a first series of valves to redirect the feedwater and a second series of valves to redirect energy from steam wherein the feedwater and the energy from steam separately travel between the multiple stages and removing the conditioning layer through the use of one or more acids in the stage of the multiple stages of the water treatment system that has been bypassed during the operation of one or more remaining stages of the multiple stages of the water treatment system, thus also removing the scale in the stage of the multiple stages of the water treatment system that has been bypassed without a complete shutdown of the water treatment system, in order to obtain a method wherein: i) both steam and feedwater flows can be made to bypass a particular stage, and ii) scale can be removed from an intermediate stage of the multiple stages without shutting down all of the evaporator stages or an entire first group of evaporator stages, such that scale can be removed from the intermediate stage of the water treatment system (evaporator) with minimal disruption to the evaporator’s productivity.
Modified Efrat does not explicitly teach that the chemical cleaner comprises one or more acids.
However, Efrat does not identify any specific examples of chemical cleaners. Thus, a person having ordinary skill in the art would look elsewhere to find examples of suitable chemical cleaners.
It is notoriously well known in the art to remove scale using acid-based cleaners. For example, Sparrow teaches a method for concentrating a solution using evaporation (Abstract, Paragraph [0001]), the method comprising the use of a “clean-in-place” solution having descaling capability, wherein the clean in place solution may comprise an acid (paragraph [0064] and [0140]). Notably, Sparrow teaches that “dilute citric acid may be used to de-scale calcium carbonate,” (paragraph [0140]), clearly indicating that citric acid solutions are suitable for removing calcium carbonate scaling. Efrat teaches that the conditioning layer (sacrificial layer) may be calcium carbonate (paragraphs [0034], [0041], and [0042]). Thus, in view of the combined teachings of Efrat and Sparrow, a person having ordinary skill in the art would have a reasonable expectation that an acid cleaning solution, e.g. a citric acid solution, could be used as the chemical cleaner for removing the conditioning layer (sacrificial layer) in Efrat.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Efrat in view of Sparrow by using an acid-based cleaning solution, i.e. a solution comprising one or more acids, as the chemical cleaner for removing the conditioning layer, and thus the scale, in Efrat, in order to obtain a predictably successful method of removing scale in accordance with the teachings of Efrat.
Modified Efrat does not explicitly teach that the mechanical weakening includes direct mechanical energy wherein direct mechanical energy comprises vibration, tapping, and/or sound.
However, use of such direct mechanical energy to clean scale from scale susceptible elements within water treatment systems (evaporators) is notoriously well known in the art. For example, Pottharst describes the use of ultrasonic vibrations for scale removal in an evaporator system as being conventional (Column 6 Lines 44-54). It is well established that it would be obvious to one of ordinary skill in the art to combine known prior art elements in order to obtain predictable results (see MPEP 2143).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Efrat in view of Pottharst by adding an element of mechanically weakening the scale through the use of direct mechanical energy (i.e. in addition to the thermal shock), wherein the direct mechanical energy comprises ultrasonic vibration, to the step of mechanically weakening the scale, in order to obtain a predictably functional method wherein scale is thoroughly cleaned from the water treatment system through the combined application of acid treatment, thermal shock, and direct mechanical energy in the form of vibration.
Citation of Pertinent Prior Art
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Childs (US 1,005,600) teaches a multi-effect evaporator system having feed liquid bypass pipes (Figure 1, Claim 1).
Daniel (US 3,179,159) teaches a multi-effect evaporator system having a steam bypass arrangement that is at least similar to that of the claims (Figures 1 and 2, Column 2).
Vander Griend (US 7,297,236) teaches a bypass arrangement at least similar to that of the Xu reference of record.
Vander Griend (US 7,572,353) teaches a bypass arrangement at least similar to that of the Xu reference of record.
Peck (US 329,073) discloses subject matter similar to that of the Peck reference cited in Examiner’s response to Applicant’s arguments above.
Conclusion
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/JONATHAN LUKE PILCHER/Examiner, Art Unit 1772