OFFICE ACTION
(Serial No. 18/857,210)
This application has been assigned or remains assigned to Technology Center 1700, Art Unit 1774 and the following will apply for this application:
Please direct all written correspondence with the correct application serial number for this application to Art Unit 1774.
Telephone inquiries regarding this application should be directed to the Electronic Business Center (EBC) at http://www.uspto.gov/ebc/index.html or 1-866-217-9197 or to the Examiner at (571) 272-1139. All official facsimiles should be transmitted to the centralized fax receiving number (571)-273-8300.
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 .
Information Disclosure Statement
Note the attached PTO-1449 forms submitted with the Information Disclosure Statements.
Drawings
The drawings are objected to under 37 CFR § 1.84 in view of the following deficiencies that require correction:
Figures 2A and 2B each should be designated by a legend such as --Prior Art-- because only that which is old is illustrated. See MPEP § 608.02(g).
distribution holes 39’ are not labeled in Figures 2A and 2B - see page 11, line 28 of the instant specification.
Applicant should review the specification and drawing Figures to ensure a proper one-to-one correspondence between the specification and drawings in accordance with MPEP 608.01(g) and 37 CFR 1.84(f). The brief description of the drawings and the descriptive portion of the specification may require revision in accordance with any drawing objections listed herein or those noticed by Applicant during said review.
From MPEP 608.01(g): The reference characters must be properly applied, no single reference character being used for two different parts or for a given part and a modification of such part. See 37 CFR 1.84(p). Every feature specified in the claims must be illustrated, but there should be no superfluous illustrations.
INFORMATION ON HOW TO EFFECT DRAWING CHANGES
Replacement Drawing Sheets
Drawing changes must be made by presenting replacement figures which incorporate the desired changes and which comply with 37 CFR 1.84. An explanation of the changes made must be presented either in the drawing amendments, or remarks, section of the amendment. Any replacement drawing sheet must be identified in the top margin as “Replacement Sheet” (37 CFR 1.121(d)) and include all of the figures appearing on the immediate prior version of the sheet, even though only one figure may be amended. The figure or figure number of the amended drawing(s) must not be labeled as “amended.” If the changes to the drawing figure(s) are not accepted by the examiner, applicant will be notified of any required corrective action in the next Office action. No further drawing submission will be required, unless applicant is notified.
Identifying indicia, if provided, should include the title of the invention, inventor’s name, and application number, or docket number (if any) if an application number has not been assigned to the application. If this information is provided, it must be placed on the front of each sheet and centered within the top margin.
Annotated Drawing Sheets
A marked-up copy of any amended drawing figure, including annotations indicating the changes made, may be submitted or required by the examiner. The annotated drawing sheets must be clearly labeled as “Annotated Marked-up Drawings” and accompany the replacement sheets.
Timing of Corrections
Applicant is required to submit acceptable corrected drawings within the time period set in the Office action. See 37 CFR 1.85(a). Failure to take corrective action within the set period will result in ABANDONMENT of the application.
If corrected drawings are required in a Notice of Allowability (PTOL-37), the new drawings MUST be filed within the THREE MONTH shortened statutory period set for reply in the “Notice of Allowability.” Extensions of time may NOT be obtained under the provisions of 37 CFR 1.136 for filing the corrected drawings after the mailing of a Notice of Allowability.
Specification
The specification has not been checked to the extent necessary to determine the presence of all possible minor errors. Applicant's cooperation is requested in correcting any errors of which applicant may become aware in the specification.
The substitute abstract is acceptable.
The title of the invention is not descriptive. A new title is required that is clearly indicative of the invention to which the claims are directed (MPEP 606.01).
Claim Rejections - 35 USC § 103
The terms used in this respect are given their broadest reasonable interpretation in their ordinary usage in context as they would be understood by one of ordinary skill in the art, in light of the written description in the specification, including the drawings, without reading into the claim any disclosed limitation or particular embodiment. See, e.g., In re Am. Acad. of Sci. Tech. Ctr., 367 F.3d 1359, 1364 (Fed. Cir. 2004); In re Hyatt, 211 F.3d 1367, 1372 (Fed. Cir. 2000); In re Morris, 127 F.3d 1048, 1054-55 (Fed. Cir. 1997); In re Zletz, 893 F.2d 319, 321-22 (Fed. Cir. 1989). The Examiner interprets claims as broadly as reasonable in view of the specification, but does not read limitations from the specification into a claim. Elekta Instr. S.A.v.O.U.R. Sci. Int'l, Inc., 214 F.3d 1302, 1307 (Fed. Cir. 2000).
To determine whether subject matter would have been obvious, "the scope and content of the prior art are to be determined; differences between the prior art and the claims at issue are to be ascertained; and the level of ordinary skill in the pertinent art resolved .... Such secondary considerations as commercial success, long felt but unsolved needs, failure of others, etc., might be utilized to give light to the circumstances surrounding the origin of the subject matter sought to be patented." Graham v. John Deere Co. of Kansas City, 383 U.S. 1, 17-18 (1966).
The Supreme Court has noted:
Often, it will be necessary for a court to look to interrelated teachings of multiple patents; the effects of demands known to the design community or present in the marketplace; and the background knowledge possessed by a person having ordinary skill in the art, all in order to determine whether there was an apparent reason to combine the known elements in the fashion claimed by the patent at issue.
KSR Int'l Co. v. Teleflex Inc., 127 S.Ct. 1727, 1740-41 (2007). "Under the correct analysis, any need or problem known in the field of endeavor at the time of invention and addressed by the patent can provide a reason for combining the elements in the manner claimed." (Id. at 1742).
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 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.
If this application currently names joint inventors, note that in considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
The instant office action conforms to the policies articulated in the Federal Register notice titled “Updated Guidance for Making a Proper Determination of Obviousness” at 89 Fed. Reg. 14449, February 27, 2024, wherein the Supreme Court’s directive to employ a flexible approach to understanding the scope of prior art is reflected in the frequently quoted sentence, ‘‘A person of ordinary skill is also a person of ordinary creativity, not an automaton.’’ Id. at 421, 127 S. Ct. at 1742. In this section of the KSR decision, the Supreme Court instructed the Federal Circuit that persons having ordinary skill in the art (PHOSITAs) also have common sense, which may be used to glean suggestions from the prior art that go beyond the primary purpose for which that prior art was produced. Id. at 421–22, 127 S. Ct. at 1742. Thus, the Supreme Court taught that a proper understanding of the prior art extends to all that the art reasonably suggests, and is not limited to its articulated teachings regarding how to solve the particular technological problem with which the art was primarily concerned. Id. at 418, 127 S. Ct. at 1741 (‘‘As our precedents make clear, however, the analysis need not seek out precise teachings directed to the specific subject matter of the challenged claim, for a court can take account of the inferences and creative steps that a person of ordinary skill in the art would employ.’’). ‘‘The obviousness analysis cannot be confined . . . by overemphasis on the importance of published articles and the explicit content of issued patents.’’ Id. at 419, 127 S. Ct. at 1741. Federal Circuit case law since KSR follows the mandate of the Supreme Court to understand the prior art— including combinations of the prior art—in a flexible manner that credits the common sense and common knowledge of a PHOSITA. The Federal Circuit has made it clear that a narrow or rigid reading of prior art that does not recognize reasonable inferences that a PHOSITA would have drawn is inappropriate. An argument that the prior art lacks a specific teaching will not be sufficient to overcome an obviousness rejection when the allegedly missing teaching would have been understood by a PHOSITA—by way of common sense, common knowledge generally, or common knowledge in the relevant art. For example, in Randall Mfg. v. Rea, 733 F.3d 1355 (Fed. Cir. 2013), the Federal Circuit vacated a determination of nonobviousness by the Patent Trial and Appeal Board (PTAB or Board) because it had not properly considered a PHOSITA’s perspective on the prior art. Id. at 1364. The Randall court recalled KSR’s criticism of an overly rigid approach to obviousness that has ‘‘little recourse to the knowledge, creativity, and common sense that an ordinarily skilled artisan would have brought to bear when considering combinations or modifications.’’ Id. at 1362, citing KSR, 550 U.S. at 415–22, 127 S. Ct. at 1727. In reaching its decision to vacate, the Federal Circuit stated that by ignoring evidence showing ‘‘the knowledge and perspective of one of ordinary skill in the art, the Board failed to account for critical background information that could easily explain why an ordinarily skilled artisan would have been motivated to combine or modify the cited references to arrive at the claimed inventions.’’ Id.
From Norgren Inc. v. Int’l Trade Comm’n, 699 F.3d 1317, 1322 (Fed. Cir. 2012) (‘‘A flexible teaching, suggestion, or motivation test can be useful to prevent hindsight when determining whether a combination of elements known in the art would have been obvious.’’); Outdry Techs. Corp. v. Geox S.p.A., 859 F.3d 1364, 1370–71 (Fed. Cir. 2017) (‘‘Any motivation to combine references, whether articulated in the references themselves or supported by evidence of the knowledge of a skilled artisan, is sufficient to combine those references to arrive at the claimed process.’’). In keeping with this flexible approach to providing a rationale for obviousness, the Federal Circuit has echoed KSR in identifying numerous possible sources that may, either implicitly or explicitly, provide reasons to combine or modify the prior art to determine that a claimed invention would have been obvious. These include ‘‘market forces; design incentives; the ‘interrelated teachings of multiple patents’; ‘any need or problem known in the field of endeavor at the time of invention and addressed by the patent’; and the background knowledge, creativity, and common sense of the person of ordinary skill.’’ Plantronics, Inc. v. Aliph, Inc., 724 F.3d 1343, 1354 (Fed. Cir. 2013), quoting KSR, 550 U.S. at 418–21, 127 S. Ct. at 1741–42.
The Federal Circuit has also clarified that a proposed reason to combine the teachings of prior art disclosures may be proper, even when the problem addressed by the combination might have been more advantageously addressed in another way. PAR Pharm., Inc. v. TWI Pharms., Inc., 773 F.3d 1186, 1197–98 (Fed. Cir. 2014) (‘‘Our precedent, however, does not require that the motivation be the best option, only that it be a suitable option from which the prior art did not teach away.’’) (emphasis in original). One aspect of the flexible approach to explaining a reason to modify the prior art is demonstrated in the Federal Circuit’s decision in Intel Corp. v. Qualcomm Inc., 21 F.4th 784, 796 (Fed. Cir. 2021), which confirms that a proposed reason is not insufficient simply because it has broad applicability. Patent challenger Intel had argued in an inter partes review before the Board that some of Qualcomm’s claims were unpatentable because a PHOSITA would have been able to modify the prior art, with a reasonable expectation of success, for the purpose of increasing energy efficiency. Id. at 796–97. The Federal Circuit explained that ‘‘[s]uch a rationale is not inherently suspect merely because it’s generic in the sense of having broad applicability or appeal.’’ Id. The Federal Circuit further pointed out its pre-KSR holding ‘‘that because such improvements are ‘technology independent,’ ‘universal,’ and ‘even common-sensical,’ ‘there exists in these situations a motivation to combine prior art references even absent any hint of suggestion in the references themselves.’ ’’ Id., quoting DyStar Textilfarben GmbH v. C.H. Patrick Co., 464 F.3d 1356, 1368 (Fed. Cir. 2006) (emphasis added by the Federal Circuit in Intel). When formulating an obviousness rejection, the PTO may use any clearly articulated line of reasoning that would have allowed a PHOSITA to draw the conclusion that a claimed invention would have been obvious in view of the facts. MPEP 2143, subsection I, and MPEP 2144. Acknowledging that, in view of KSR, there are ‘‘many potential rationales that could make a modification or combination of prior art references obvious to a skilled artisan,’’ the Federal Circuit has also pointed to MPEP 2143, which provides several examples of rationales gleaned from KSR. Unwired Planet, 841 F.3d at 1003.
When considering the prior art in its entirety, note Allied Erecting v. Genesis Attachments, 825 F.3d 1373, 1381, 119 USPQ2d 1132, 1138 (Fed. Cir. 2016) ("Although modification of the movable blades may impede the quick change functionality disclosed by Caterpillar, ‘[a] given course of action often has simultaneous advantages and disadvantages, and this does not necessarily obviate motivation to combine.’" (quoting Medichem, S.A. v. Rolabo, S.L., 437 F.3d 1157, 1165, 77 USPQ2d 1865, 1870 (Fed Cir. 2006) (citation omitted))). However, "the prior art’s mere disclosure of more than one alternative does not constitute a teaching away from any of these alternatives because such disclosure does not criticize, discredit, or otherwise discourage the solution claimed…." In re Fulton, 391 F.3d 1195, 1201, 73 USPQ2d 1141, 1146 (Fed. Cir. 2004).
In view of the 103 guidance above, claims 1-20 are rejected under 35 U.S.C. 103 as being unpatentable over in view of BORGSTROM et al. (US 2018/0117601) in view of HEINRICH (US 7410457).
BORGSTROM et al. discloses the recited subject matter substantially as claimed including an apparatus for and a method of supervising an E-line interface position in a centrifugal separator configured to separate a heavy liquid phase and a light liquid phase from a liquid feed mixture. Inside a rotating rotor of a centrifugal separator, an interface between a heavy liquid phase and light liquid phase is formed. The interface also may be referred to as an E-line. The position of the interface is important for the separation performance of the centrifugal separator. If the interface is positioned too far radially outwards, light liquid phase will escape through an outlet for heavy liquid phase, and vice versa. Moreover, at an optimal position of the interface, the full capacity of the centrifugal separator may be utilized. If the interface is positioned radially inwards from this optimal position, e.g. to avoid that the interface will be positioned too far radially outwards, the full capacity of the centrifugal separator is not utilized.
Such a centrifugal separator comprises a rotor, a stack of conical separation disks arranged inside the rotor, an inlet for the liquid feed mixture into the rotor, a first outlet passage for the light liquid phase from the rotor, a second outlet passage for the heavy liquid phase from the rotor. An inlet side of the first outlet passage is arranged at a first radius and an inlet side of the second outlet passage is arranged at a second radius. The method comprising steps of: rotating the rotor at an angular speed, feeding the liquid feed mixture into the rotor, monitoring a density of the light liquid phase, monitoring a density of the heavy liquid phase, monitoring a pressure at an outlet side of the first outlet passage and/or at an outlet side of the second outlet passage, monitoring a first parameter related to a first pressure drop between the E-line position and the outlet side of the first outlet passage, monitoring a second parameter related to a second pressure drop between the E-line position and the outlet side of the second outlet passage, and continuously calculating a parameter related to the E-line position based on: the first radius, the second radius, the angular speed, the monitored density of the light liquid phase, the monitored density of the heavy liquid phase, the monitored pressure at the outlet side of the first outlet passage and/or at the outlet side of the second outlet passage, the monitored first parameter related to a first pressure drop between the E-line position and the outlet side of the first outlet passage, and the monitored second parameter related to a second pressure drop between the E-line position and the outlet side of the second outlet passage.
Since a parameter related to the E-line position is continuously calculated based on the monitored densities of the light liquid phase and the heavy liquid phase, the monitored pressure at the outlet side of the first outlet passage and/or at the outlet side of the second outlet passage, the monitored first parameter and the monitored second parameter, a basis for reliably supervised the E-line position is provided.
The rotor of the centrifugal separator is rotated about a rotation axis. The first and second radii are measured from the rotation axis to the respective inlet sides of the first and second outlet passages. The light liquid phase flows out of the centrifugal separator through the first outlet passage. The heavy liquid phase flows out of the centrifugal separator through the second outlet passage. The centrifugal separator may be configured to separate a component of higher density than the heavy liquid phase, from the liquid mixture. The component may comprise solid matter and/or sludge. The densities of the light liquid phase and the heavy liquid phase may be directly monitored or indirectly monitored. The term “continuously calculating”, in the context of continuously calculating a parameter related to the E-line position, entails that the parameter related to the E-line position is calculated at discrete instances, more or less regularly over time. The frequency of such discrete instances may depend on the temporal variation in composition of liquid feed mixture fed into the centrifugal separator. The parameter related to the E-line position may be the actual radius of the E-line in the rotor. However, other parameters related to the E-line position may alternatively be calculated, such as e.g. a pressure at an outlet for the heavy liquid phase and/or an outlet for the light liquid phase.
The step of monitoring the density of the light liquid phase may comprise monitoring a temperature of the light liquid phase or of the liquid feed mixture, and the step of monitoring the density of the heavy liquid phase may comprise monitoring a temperature of the heavy liquid phase or of the liquid feed mixture. The step of continuously calculating a parameter related to the E-line position may comprise: calculating the density of the light liquid phase based on the monitored temperature of the light liquid phase or of the liquid feed mixture, and calculating the density of the heavy liquid phase based on the monitored temperature of the heavy liquid phase or of the liquid feed mixture. In this manner densities of the light liquid phase and the heavy liquid phase may be indirectly monitored and may easily be established based on the monitored the temperatures of the light liquid phase and of the heavy liquid phase, or of the liquid feed mixture. In the latter case it is assumed that the temperatures of the light and heavy liquid phases are the same as that of the liquid feed mixture.
There is provided a computer program configured to perform a method of supervising an E-line position in a centrifugal separator. There is provided a computer program product comprising computer readable code configured to cause a control system associated with a centrifugal separator to perform a method of supervising an E-line position in a centrifugal separator according to any one aspect and/or embodiment disclosed herein. Such a computer program product may for instance be a CD-ROM disc, a USB memory device, a hard disc drive, a ROM chip or EPROM chip.
A method of controlling an E-line position in a centrifugal separator configured to separate a heavy liquid phase and a light liquid phase from a liquid feed mixture, the centrifugal separator comprising a rotor being rotatable about a rotation axis, a stack of conical separation disks arranged inside the rotor, an inlet for the liquid feed mixture into the rotor, a first outlet passage for the light liquid phase from the rotor, a second outlet passage for the heavy liquid phase from the rotor, wherein an inlet side of the first outlet passage is arranged at a first radius and an inlet side of the second outlet passage is arranged at a second radius, wherein the centrifugal separator further comprises a controllable first valve for controlling a pressure at an outlets side of the first outlet passage and/or a controllable second valve for controlling a pressure at an outlet side of the second outlet passage. The method of controlling an E-line position includes a method of supervising an E-line position in a centrifugal separator according to any one aspect and/or embodiment disclosed herein, and further comprises steps of:
increasing a pressure at the outlet side of the second outlet passage using the second valve, and/or reducing a pressure at the outlet side of the first outlet passage using the first valve, if the actual E-line position extends radially outside an E-line position set point. Since the E-line position is reliably supervised as discussed above and the second valve is utilized to increase the pressure at the outlet side of the second outlet passage, and/or the first valve is utilized to decrease the pressure at the first outlet passage, the E-line position is adjusted radially inwardly towards the E-line set point when so required. Moreover, since the E-line position is supervised, and accordingly a parameter related to the E-line position is continuously calculated, the E-line position is controlled in a manner, which does not require direct measurement of the actual E-line position. Put differently, the E-line position is controlled based on a calculated parameter related to the E-line position. One of the advantages with the present invention is that it is possible to compensate for an irregular liquid feed mixture temperature into the inlet of the centrifugal separator.
According to embodiments the method of controlling an E-line position may comprise steps of: reducing a pressure at the outlet side of the second outlet passage using the second valve, and/or increasing a pressure at the outlet side of the first outlet passage using the first valve, if the actual E-line position extends radially inside an E-line position set point. In this manner the E-line position may be adjusted radially outwardly towards the E-line set point when so required.
According to embodiments the pressure at the outlet side of the second outlet passage, or the pressure at the outlet side of the first outlet passage, may be controlled by a manipulated variable of a PI control algorithm for controlling the E-line position in the centrifugal separator. In this manner the E-line position may be controlled with a PI control algorithm by letting the PI control algorithm control the pressure at the outlet side of the second outlet passage, or at the outlet side of the first outlet passage, utilizing the E-line position calculated by the method of supervising the E-line position.
According to embodiments the rotor may comprise at least one peripherally arranged nozzle opening for continuously ejecting solid matter and/or sludge from the rotor during rotation of the rotor. The method further may comprise a step of:
adding heavy liquid phase into the rotor if the flow of heavy liquid phase through the at least one nozzle opening exceeds the heavy liquid phase content of the liquid feed mixture.
In this manner the E-line position may be adjusted towards the E-line position set point in a centrifugal separator provided with peripheral nozzle openings for ejecting solid matter and/or sludge from the rotor if the liquid feed mixture should contain too little water. The heavy liquid phase may be added into the rotor e.g. via the second outlet passage, via a separate conduit leading into the peripheral portion of the rotor, or by adding heavy liquid phase to the liquid feed mixture.
There is provided a computer program configured to perform a method of controlling an E-line position in a centrifugal separator and a computer program product comprising computer readable code configured to cause a control system associated with a centrifugal separator to perform a method of controlling an E-line position in a centrifugal separator according to any one aspect and/or embodiment disclosed herein. Such a computer program product may for instance be a CD-ROM disc, a USB memory device, a hard disc drive, a ROM chip, or an EPROM chip.
There is provided a centrifugal separator configured to separate a heavy liquid phase and a light liquid phase from a liquid feed mixture. The centrifugal separator comprises a rotor being rotatable about a rotation axis, a stack of conical separation disks arranged inside the rotor, an inlet for the liquid feed mixture into the rotor, a first outlet passage for the light liquid phase from the rotor, and a second outlet passage for the heavy liquid phase from the rotor. An inlet side of the first outlet passage is arranged at a first radius and an inlet side of the second outlet passage is arranged at a second radius. The centrifugal separator further comprises a controllable first valve for controlling a pressure at an outlets side of the first outlet passage and/or a controllable second valve for controlling a pressure at an outlet side of the second outlet passage, and a control system configured to perform a method of controlling an E-line position in a centrifugal separator according to any one aspect and/or embodiment disclosed herein.
The centrifugal separator may be further configured to separate solid matter and/or sludge from the liquid mixture. The rotor may comprise discharge ports for intermittent discharge of the separated solid and/or sludge. In this manner solid matter and/or sludge collected at an inner periphery of the separator bowl may be ejected from the separator bowl through the discharge ports. The discharge ports may be intermittently opened by a control system of the centrifugal separator. In order to achieve an intermittent opening of the discharge ports, the rotor may comprise an upper bowl portion and a lower bowl portion. When the upper and lower bowl portions are separated, the solid matter and/or sludge may flow out through the discharge ports. An intermittent separating of the upper and lower bowl portions may be controlled by the control system.
According to embodiments the centrifugal separator may be further configured to separate solid matter and/or sludge from the liquid mixture. The rotor comprises at least one peripherally arranged nozzle opening for continuously ejecting the solid matter and/or sludge from the rotor during rotation of the rotor. In this manner solid matter and/or sludge may be separated from the liquid mixture and may be continuously discharged through the at least one nozzle opening. The solid matter and/or sludge forms a component of higher density than the heavy liquid phase, to be separated from the liquid mixture.
FIG. 1a illustrates a partial cross section through a portion of a centrifugal separator 2 according to embodiments. The centrifugal separator 2 comprises a rotor 4 being rotatable about a rotation axis 6 and a stack of conical separation disks 8 arranged inside the rotor 4. The rotor 4 is arranged in a non-shown separator housing. The stack of separation discs 8 is arranged between a top disc 7 and a bottom disc 9, which also may be referred to as a distributor. A separation space 5 is formed between the top disc 7 and the bottom disc 9 in the rotor 4. The centrifugal separator 2 further comprises a centrally arranged inlet 10 into the rotor 4, a first outlet passage 12 from the rotor 4, and a second outlet passage 14 from the rotor 4.
The centrifugal separator 2 is configured to separate a light liquid phase and a heavy liquid phase from a liquid feed mixture. The liquid feed mixture enters the rotor 4 via the inlet 10 during rotation of the rotor 4. The liquid fed mixture flows below the bottom disc 9 to one or more so-called distribution channels 15 formed through the bottom disc 9 and by holes or slots in the separation discs 8. Through the distribution channels 15 the liquid feed mixture is distributed in the stack of separation discs 8 and the separation space 5. In the stack of separation discs 8 the liquid feed mixture is separated into the light liquid phase and the heavy liquid phase. An interface between the light and heavy liquid phases, a so-called E-line 21, is formed in the rotor 4. The light liquid phase flows, or is pumped, from the rotor 4 via the first outlet passage 12. Similarly, the heavy liquid phase flows, or is pumped, from the rotor 4 via the second outlet passage 14. Inter alia, the first and second outlet passages 12, 14 and their particular arrangement determine the radius of the E-line 21 in the centrifugal separator 2. The radius of the E-line 21 may also be referred to as the E-line position. In this context it may be mentioned that in an intermediate zone between the heavy liquid phase and the light liquid phase there is a concentration gradient. The E-line, equilibrium line, is a simplification of this intermediate zone as a distinct interface between the two liquid phases.
In a centrifugal separator, the E-line position may be controlled without stopping the centrifugal separator for changing a gravity disc. FIG. 3a illustrates a cross section through a portion of a centrifugal separator 2. The centrifugal separator 2 comprises a controllable first valve 28, by means of which the backpressure at an outlet side of the first outlet passage 12 is controllable. Thus, a control system 25 of the centrifugal separator 2 may control the controllable first valve 28 to control the backpressure on the light liquid phase outlet side to maintain the E-line 21 at an optimal radius in the separation space 5. FIG. 3b illustrates a cross section through a portion of a centrifugal separator 2 wherein for controlling the E-line position in the centrifugal separator 2, the centrifugal separator 2 comprises a controllable second valve 30, by means of which the backpressure at an outlet side of the second outlet passage 14 is controllable. Thus, a control system 25 of the centrifugal separator 2 may control the controllable second valve 30 and the backpressure on the heavy liquid phase outlet side to maintain the E-line at an optimal radius in the separation space 5.
Accordingly, in the centrifugal separators 2 of FIGS. 3a and 3b an inlet side of the first outlet passage 12 is arranged at a first radius and an inlet side of the second outlet passage 14 is arranged at a second radius. The centrifugal separator 2 of FIG. 3a further comprises a controllable first valve 28 for controlling a pressure at an outlets side of the first outlet passage 12 and the centrifugal separator 2 of FIG. 3b comprises a controllable second valve 30 for controlling a pressure at an outlet side of the second outlet passage 14. The control system 25 may be configured to perform a method of controlling an E-line position in a centrifugal separator 2 according to any one aspect and/or embodiment disclosed herein. In alternative embodiments a centrifugal separator may comprise both controllable first and second valves 28, 30.
The control system 25 may comprise a microprocessor 26 configured to execute computer readable code of a computer program. The computer program may be configured to perform a method of supervising and/or controlling the E-line position in a centrifugal separator. Thus, the microprocessor 26 also may control the pressure at the outlet side of the first and/or second outlet passage 12, 14 by controlling the controllable first and/or second valves 28, 30. Optionally, the control system 25 may control the adding of water into the rotor, see below. The control system 25 may further for example comprise one or more of coriolis type mass flow meters 31, 31′, 31″, pressure sensors 33, 33′, 33″, and temperature sensors 35, 35′, 35″, which communicate with the microprocessor 26 for monitoring/measuring/sensing one or more of density, mass flow, volume flow, fluid pressure, and temperature of the liquid feed mixture, and/or the light liquid phase, and/or the heavy liquid phase.
According to alternative embodiments, the PI algorithm may utilize pressure instead of a radial position of the E-line to control the E-line position. The set point pressure in the outlet passage 14 of the heavy liquid phase, which set point pressure is required in order to maintain the E-line 21 at the optimal position as parameters of the separation process vary over time. Since parameters of the separation process, such as temperature, density, etc. vary in time, the pressure needed to control the E-line to the set point also is varying in time. A control signal is provided by the control system 25 to the controllable second valve 30 for controlling the backpressure on the heavy liquid phase outlet in order to maintain the E-line 21 at the desired position.
As in the embodiments of FIG. 3b, also in the embodiments of FIG. 3a the PI algorithm may alternatively utilize pressure to control the first valve 28 in order to maintain the E-line at the desired position.
A control signal from which the control system 25 controls the controllable first valve 28 to control the backpressure on the light liquid phase outlet, or the controllable second valve 30 to control the backpressure on the heavy liquid phase outlet, in order to maintain the E-line position at the E-line set point. A control strategy may be devised to determine when the backpressure on the light liquid phase outlet is controlled via the first valve 28, and when the backpressure on the heavy liquid phase outlet is controlled via the controllable second valve 30. According to one example, the control strategy may involve controlling the backpressure only on the heavy liquid phase outlet via the controllable second valve 30 if the difference between the process value and the set point exceeds a threshold value, and controlling the backpressure only on the light liquid phase outlet via the controllable first valve 28 if the difference between the process value and the set point does not exceed the threshold value.
As in the above discussed embodiments of FIGS. 3b and 3a, also in the embodiments with both the first and second valves 28, 30, the PI algorithm may alternatively utilize pressure in order to control the first valve 28 and the second valve 30.
Depending on the relevant separation process there are various different possible variables. For instance, the temperature of the liquid feed mixture may vary. Thus, the density of the light and/or heavy liquid phase may vary. The densities may be calculated as a function of liquid feed mixture temperature, or as functions of the individual temperatures of the light liquid phase and the heavy liquid phase. Alternatively, the densities may be measured using a coriolis type mass flow meter or other suitable instrument. The amounts of light and/or heavy liquid phase may vary in the liquid feed mixture. The flow rate of the liquid feed mixture may vary. The backpressures are measured. The gas pressures on the light and heavy liquid phase side may be measured, or may be set as constant values. The different pressures are functional relationships known to the skilled person and may be calculated from known variables such as rotor speed, flow rates, densities, viscosities, and design parameters. The design parameters relate to the relevant type of centrifugal separator and are known to the skilled person such as light liquid phase flow rate, light liquid phase viscosity and design dimensions of the relevant centrifugal separator. The pressure drop in the stack of separation discs from the E-line positon and inwards to the light liquid phase outlet is included in this pressure drop that is a function of heavy liquid phase flow rate, heavy liquid phase viscosity and design dimensions. The pressure drop in the stack of separation discs from the E-line position and outwards is included in this pressure drop.
The E-line position is calculated using pressure balance equations, measurable data, and measured or a priori known fluid properties to calculate a radial E-line position or a pressure set point. This calculated radial E-line position, or pressure set point, is used in a control algorithm used to adjust the actual E-line position to a desired E-line position by adjusting a backpressure on the heavy liquid phase outlet side, or on the light liquid outlet side, or on both the heavy and light liquid outlet sides. This provides a fast and accurate compensation for change in process parameters allowing the E-line position to be maintained at an optimum/desired position at all time.
With reference to FIG. 3b, the back pressure on the heavy liquid phase outlet side is controlled via the controllable second valve 30 to maintain a desired/optimal E-line position. With reference to FIG. 3a, the backpressure on the light liquid phase outlet side is controlled via the controllable first valve 28 to maintain a desired/optimal E-line position. The control system 25 is configured to control both the first and second valves 28, 30. Moreover, there are centrifugal separators with hermetically mechanically sealed inlets and outlets, often referred to as hermetic inlet and outlet, respectively. Similar balance equations may be set up for such centrifugal separators thus, providing a simulation tool for calculation of the E-line position or pressure in such centrifugal separators. Thus calculated E-line position or pressure is then used in a control algorithm for controlling the E-line position in the same way as in the previously discussed embodiments.
FIG. 4 illustrates a method 100 of supervising an E-line position in a centrifugal separator. The centrifugal separator is configured to separate a heavy liquid phase and a light liquid phase from a liquid feed mixture, and may be a centrifugal separator according to any of the embodiments discussed in connection with FIGS. 3a and 3b. Corresponding equations for continuously calculating the pressure at the light and/or heavy liquid outlet side may be utilized during the supervising of the E-line position. Accordingly, the centrifugal separator 2 comprises a rotor 4, a stack of conical separation disks 8 arranged inside the rotor 4, an inlet 10 for the liquid feed mixture into the rotor, a first outlet passage 12 for the light liquid phase from the rotor, a second outlet passage 14 for the heavy liquid phase from the rotor. An inlet side of the first outlet passage 12 is arranged at a first radius and an inlet side of the second outlet passage 14 is arranged at a second radius.
The method 100 of supervising an E-line position comprises steps of rotating 102 the rotor 4 at an angular speed ω, feeding 104 the liquid feed mixture into the rotor 4, monitoring 106 a density of the light liquid phase, monitoring 108 a density of the heavy liquid phase, monitoring 110 a pressure at an outlet side of the first outlet passage 12 and/or at an outlet side of the second outlet passage 14,monitoring 112 a first parameter related to a first pressure drop between the E-line position and the outlet side of the first outlet passage 12, monitoring 114 a second parameter related to a second pressure drop between the E-line position and the outlet side of the second outlet passage 14, and continuously calculating 116 a parameter related to the E-line position, or corresponding based on: the first radius, the second radius, the angular speed ω, the monitored density of the light liquid phase, the monitored density of the heavy liquid phase, the monitored pressure at the outlet side of the first outlet passage 12 and/or at the outlet side of the second outlet passage 14, the monitored first parameter related to a first pressure drop between the E-line position and the outlet side of the first outlet passage, and the monitored second parameter related to a second pressure drop between the E-line position and the outlet side of the second outlet passage.
As an example, the step of continuously calculating 116 a parameter related to the E-line position may entail that the parameter related to the E-line position is calculated at least 6 times per minute, which calculation frequency may provide a sufficient accuracy for controlling the E-line position. However, a higher calculation frequency may provide a more accurate supervision of the E-line position. Accordingly, the step of continuously calculating 116 a parameter related to the E-line position may entail that the parameter related to the E-line position is calculated up to several times per second.
The step of monitoring 106 the density of the light liquid phase may comprise monitoring 118 a temperature of the light liquid phase or of the liquid feed mixture, and the step of monitoring 108 the density of the heavy liquid phase may comprise monitoring 120 a temperature of the heavy liquid phase or of the liquid feed mixture. The step of continuously calculating 116 a parameter related to the E-line position may comprise: calculating 122 the density of the light liquid phase based on the monitored temperature of the light liquid phase or of the liquid feed mixture, and calculating 124 the density of the heavy liquid phase based on the monitored temperature of the heavy liquid phase or of the liquid feed mixture. Calculating 122, 124 the densities of the light and/or heavy liquid phases may include selecting density values from lookup tables, which list the densities of the light and/or heavy liquid phases at various relevant temperatures. Alternatively, or additionally, calculating 122, 124 the densities of the light and/or heavy liquid phases may include interpolating between calculated density values, or between density values from tables, which list the densities of the light and/or heavy liquid phases at various temperatures.
According to embodiments the first parameter related to the first pressure drop may comprise a flow rate of the light liquid phase. The step of continuously calculating 116 a parameter related to the E-line position may comprise calculating 126 the first pressure drop based on the flow rate of the light liquid phase, the density of the light liquid phase, the rotational speed ω, and one or more centrifugal separator specific parameters. Thus, the step of monitoring 112 a first parameter related to a first pressure drop may comprise monitoring the flow rate of the light liquid phase. The density is provided by the step 106. The one or more centrifugal specific parameters depend on the relevant centrifugal separator, and are known to the skilled person.
According to embodiments the second parameter related to the second pressure drop may comprise a flow rate of the heavy liquid phase. The step of continuously calculating 116 a parameter related to the E-line position may comprise calculating 128 the second pressure drop based on the flow rate of the heavy liquid phase, the density of the heavy liquid phase, the rotational speed ω, and one or more centrifugal separator specific parameters. Thus, the step of monitoring 114 a second parameter related to a second pressure drop may comprise monitoring the flow rate of the heavy liquid phase. The density is provided by the step 108. The one or more centrifugal specific parameters depend on the relevant centrifugal separator, and are known to the skilled person.
A computer program may be configured to perform a method of supervising an E-line position in a centrifugal separator. FIG. 6 illustrates a computer program product according to embodiments comprising a CD-ROM disc 300. The computer program product comprises computer readable code configured to cause a control system associated with a centrifugal separator to perform a method of supervising an E-line position in a centrifugal separator as discussed above. Such a computer program product may for instance be a CD-ROM disc, a USB memory device, a hard disc drive, a ROM or an EPROM chip.
FIG. 5 illustrates a method 200 of controlling an E-line position in a centrifugal separator configured to separate a heavy liquid phase and a light liquid phase from a liquid feed mixture. The centrifugal separator may be a centrifugal separator 2 according to any of the embodiments discussed in connection with FIGS. 3a and 3b. The centrifugal separator 2 comprises a rotor 4 being rotatable about a rotation axis 6, a stack of conical separation disks 8 arranged inside the rotor 4, an inlet 10 for the liquid feed mixture into the rotor 4, a first outlet passage 12 for the light liquid phase from the rotor 4, a second outlet passage 14 for the heavy liquid phase from the rotor 4, wherein an inlet side of the first outlet passage 12 is arranged at a first radius and an inlet side of the second outlet passage 14 is arranged at a second radius, wherein the centrifugal separator 2 further comprises a controllable first valve 28 for controlling a pressure at an outlets side of the first outlet passage 12, and/or a controllable second valve 30 for controlling a pressure at an outlet side of the second outlet passage 14, the method 200 of controlling an E-line position including a method 100 of supervising an E-line position in a centrifugal separator according to any one aspect and/or embodiment discussed above, and further comprising steps of: Increasing 202 the pressure at the outlet side of the second outlet passage 14 using the second valve 30, and/or reducing 204 a pressure at the outlet side of the first outlet passage 12 using the first valve 28, if the actual E-line position extends radially outside an E-line position set point. Thus, the E-line position is controlled based on the supervised E-line position calculated according to the method 100 of supervising an E-line position as discussed above.
The method 200 of controlling an E-line position may further comprise steps of: reducing 206 a pressure at the outlet side of the second outlet passage 14 using the second valve 30, and/or increasing 208 a pressure at the outlet side of the first outlet passage 12 using the first valve 28, if the actual E-line position extends radially inside an E-line position set point. Thus, the E-line position is controlled based on the supervised E-line position calculated according to the method 100 of supervising an E-line position as discussed above. The pressure at the outlet side of the second outlet passage 14, and/or the pressure at the outlet side of the first outlet passage 12 may be controlled by a manipulated variable of a PI control algorithm for controlling the E-line position in the centrifugal separator. Thus, the pressure at the outlet side of the second outlet passage, or the pressure at the outlet side of the first outlet passage, may be controlled based on equations, in order to reliably control the E-line position at a desired set point.
According to embodiments the rotor 4 comprises at least one peripherally arranged nozzle opening 27 for ejecting the solid matter and/or sludge from the rotor 4 during rotation of the rotor 4, as discussed in connection with FIG. 1b. The method 200 of controlling an E-line position may further comprising a step of: adding 210 heavy liquid phase into the rotor 4 if the flow of heavy liquid phase through the at least one nozzle opening 27 exceeds the heavy liquid phase content of the liquid feed mixture.
Thus, pure heavy liquid phase is added into the rotor 4 to prevent the E-line from moving too far radially outwardly, which would entail that light liquid phase flows out of the rotor 4 via the second outlet passage 14, and even through the at least one nozzle opening 27.
According to some embodiments, the liquid feed mixture may comprise water and oil. In such embodiments water is added into the rotor 4 in the step of adding 210 heavy liquid phase into the rotor 4 if the liquid feed mixture should contain too little water. Water may be added for instance via the second outlet passage 14, or via a pump 34 and a valve 36 controlled by the control system 25, as illustrated in FIG. 3b. If water is added into the rotor in this manner, the temperature of the water, i.e. of the heavy liquid phase, for the purpose of supervising and/or controlling the E-line position is determined by the temperature of the mixed water, i.e. the mixture of added water and water of the liquid feed mixture.
A decreasing pressure at the heavy liquid phase outlet may indicate that the heavy liquid phase content of the liquid feed mixture is decreasing, which requires the adding 210 of heavy liquid phase. At a threshold heavy liquid phase pressure value heavy liquid phase may be added into the rotor. Heavy liquid phase may be added at increasing rate if the pressure at the heavy liquid phase outlet continues to decrease from the threshold heavy liquid phase pressure value. If the pressure at the heavy liquid phase outlet increases again, adding of heavy liquid phase may be decreased and finally stopped. Alternatively, a threshold level of the E-line position may indicate that the heavy liquid phase content of the liquid feed mixture is decreasing, which requires the adding 210 of heavy liquid phase. The threshold level of the E-line position may for instance be set at the outer radius of the stack of separation discs 8.
A computer program may be configured to perform the method 200 of controlling an E-line position in a centrifugal separator according to any one aspect and/or embodiments disclosed herein. FIG. 6 illustrates a computer program product according to embodiments comprising a CD-ROM disc 300. The computer program product comprises computer readable code configured to cause a control system associated with a centrifugal separator to perform a method of controlling an E-line position in a centrifugal separator according to any one any one aspect and/or embodiment disclosed herein. The control system may be a control system 25 as discussed in connection with FIGS. 3a and 3b.
The apparatus and method thus including a method of supervising an E-line position in a centrifugal separator configured to separate a heavy liquid phase and a light liquid phase from a liquid feed mixture, the centrifugal separator comprising a rotor, a stack of conical separation disks arranged inside the rotor, an inlet for the liquid feed mixture into the rotor, a first outlet passage for the light liquid phase from the rotor, a second outlet passage for the heavy liquid phase from the rotor, wherein an inlet side of the first outlet passage is arranged at a first radius and an inlet side of the second outlet passage is arranged at a second radius, the method comprising steps of: rotating the rotor at an angular speed (ω), feeding the liquid feed mixture into the rotor, monitoring a density of the light liquid phase, monitoring a density of the heavy liquid phase, monitoring a pressure at an outlet side of the first outlet passage and/or at an outlet side of the second outlet passage, monitoring a first parameter related to a first pressure drop between the E-line position and the outlet side of the first outlet passage, monitoring a second parameter related to a second pressure drop between the E-line position and the outlet side of the second outlet passage, and continuously calculating a parameter related to the E-line position based on: the first radius, the second radius, the angular speed (ω), the monitored density of the light liquid phase, the monitored density of the heavy liquid phase, the monitored pressure at the outlet side of the first outlet passage and/or at the outlet side of the second outlet passage, the monitored first parameter related to a first pressure drop between the E-line position and the outlet side of the first outlet passage, and the monitored second parameter related to a second pressure drop between the E-line position and the outlet side of the second outlet passage; wherein the step of monitoring a density of the light liquid phase comprises monitoring a temperature of the light liquid phase or of the liquid feed mixture, wherein the step of monitoring the density of the heavy liquid phase comprises monitoring a temperature of the heavy liquid phase or of the liquid feed mixture, and wherein the step of continuously calculating a parameter related to the E-line position comprises: calculating the density of the light liquid phase based on the monitored temperature of the light liquid phase or of the liquid feed mixture, and calculating the density of the heavy liquid phase based on the monitored temperature of the heavy liquid phase or of the liquid feed mixture; wherein the first parameter related to the first pressure drop comprises a flow rate of the light liquid phase, and wherein the step of continuously calculating a parameter related to the E-line position comprises calculating the first pressure drop based on the flow rate of the light liquid phase, the density of the light liquid phase, the rotational speed (ω), and one or more centrifugal separator specific parameters; wherein the second parameter related to the second pressure drop comprises a flow rate of the heavy liquid phase, and wherein the step of continuously calculating a parameter related to the E-line position comprises calculating the second pressure drop based on the flow rate of the heavy liquid phase, the density of the heavy liquid phase, the rotational speed (ω), and one or more centrifugal separator specific parameters; and a computer program embodied on a non-transitory computer readable medium and configured to perform this method of supervising an E-line position in a centrifugal separator or a computer program product comprising computer readable code embodied on a non-transitory computer readable medium and configured to cause a control system associated with a centrifugal separator to perform the method of supervising an E-line position in a centrifugal separator.
The apparatus and method thus including a method of controlling an E-line position in a centrifugal separator configured to separate a heavy liquid phase and a light liquid phase from a liquid feed mixture, the centrifugal separator comprising a rotor being rotatable about a rotation axis, a stack of conical separation disks arranged inside the rotor, an inlet for the liquid feed mixture into the rotor, a first outlet passage for the light liquid phase from the rotor, a second outlet passage for the heavy liquid phase from the rotor, wherein an inlet side of the first outlet passage is arranged at a first radius and an inlet side of the second outlet passage is arranged at a second radius, wherein the centrifugal separator further comprises a controllable first valve for controlling a pressure at an outlets side of the first outlet passage, and/or a controllable second valve for controlling a pressure at an outlet side of the second outlet passage, the method of controlling the E-line position and further comprising steps of increasing the pressure at the outlet side of the second outlet passage using the second valve, and/or reducing the pressure at the outlet side of the first outlet passage using the first valve, if the actual E-line position extends radially outside an E-line position set point; reducing the pressure at the outlet side of the second outlet passage using the second valve, and/or increasing the pressure at the outlet side of the first outlet passage using the first valve, if the actual E-line position extends radially inside an E-line position set point; wherein the pressure at the outlet side of the second outlet passage or the pressure at the outlet side of the first outlet passage is controlled by a manipulated variable of a PI control algorithm for controlling the E-line position in the centrifugal separator; and wherein the rotor comprises at least one peripherally arranged nozzle opening for continuously ejecting solid matter and/or sludge from the rotor during rotation of the rotor, the method further comprising a step of: adding heavy liquid phase into the rotor if the flow of heavy liquid phase through the at least one nozzle opening exceeds the heavy liquid phase content of the liquid feed mixture.
The apparatus including a centrifugal separator configured to separate a heavy liquid phase and a light liquid phase from a liquid feed mixture, the centrifugal separator comprising a rotor being rotatable about a rotation axis, a stack of conical separation disks arranged inside the rotor, an inlet for the liquid feed mixture into the rotor, a first outlet passage for the light liquid phase from the rotor, a second outlet passage for the heavy liquid phase from the rotor, wherein an inlet side of the first outlet passage is arranged at a first radius and an inlet side of the second outlet passage is arranged at a second radius, wherein the centrifugal separator further comprises a controllable first valve for controlling a pressure at an outlets side of the first outlet passage, and/or a controllable second valve for controlling a pressure at an outlet side of the second outlet passage, and a control system; wherein the centrifugal separator is further configured to separate solid matter and/or sludge from the liquid mixture, wherein the rotor comprises discharge ports for intermittent discharge of the separated solid and/or sludge from the liquid mixture; wherein the centrifugal separator is further configured to separate solid matter and/or sludge from the liquid mixture, wherein the rotor comprises at least one peripherally arranged nozzle opening for continuously ejecting the solid matter and/or sludge from the rotor during rotation of the rotor; wherein the first parameter related to the first pressure drop comprises a flow rate of the light liquid phase, and wherein the step of continuously calculating a parameter related to the E-line position comprises calculating the first pressure drop based on the flow rate of the light liquid phase, the density of the light liquid phase, the rotational speed (ω), and one or more centrifugal separator specific parameters; wherein the second parameter related to the second pressure drop comprises a flow rate of the heavy liquid phase, and wherein the step of continuously calculating a parameter related to the E-line position comprises calculating the second pressure drop based on the flow rate of the heavy liquid phase, the density of the heavy liquid phase, the rotational speed (ω), and one or more centrifugal separator specific parameters; wherein the second parameter related to the second pressure drop comprises a flow rate of the heavy liquid phase, and wherein the step of continuously calculating a parameter related to the E-line position comprises calculating the second pressure drop based on the flow rate of the heavy liquid phase, the density of the heavy liquid phase, the rotational speed (ω), and one or more centrifugal separator specific parameters.
Accordingly, BORGSTROM et al. discloses the recited purification system with a disc stack centrifuge, pressure control device, and control system that executes the recited control protocol of the system but does not disclose the claimed distribution part.
HEINRICH discloses an analogous disc stack centrifuge in Figure 9 including discs 1 having distribution parts 3 that extend over the recited percentage of the distance (d) and being disposed closer to the base periphery of the disc than to the top periphery - see elongated distribution part 3 in Figure 4.
It would have been obvious to one skilled in the art before the effective filing date of the invention to have modified the distribution parts 15 in BORGSTROM et al. to be elongated over the distance (d) and closer to the base periphery of the disc as taught by HEINRICH such that a geometry of the bores of the discs of the at least one channel, which may be a rising channel [distribution part] in such a manner that, during the operation, gaps between the discs are uniformly charged with liquid over the entire height of the disc stack and as a result of this advantageous measure, the flow conditions in the centrifuge are clearly optimized. (per col. 2, lines 33-38).
Assuming, arguendo, that HEINRICH does not disclose the recited broad percentage range of the distance (d) in Figure 4, with respect to the limitation of the parameter regarding the percentage range of the distance - over 20-70% of the distance (d) - which is an exceedingly broad range present in the claim(s) at issue, the examiner has found that the specification contained no disclosure of any unexpected results arising therefrom, and that as such this broad parameter is arbitrary and therefore obvious. Such unsupported limitations cannot be a basis for patentability, since where patentability is said to be based upon particular chosen parameters or upon another variable recited in a claim, the applicant must show that the chosen dimensions are critical. In re Woodruff, 919 F.2d 1575, 1578, 16 USPQ2d 1934, 1936 (Fed. Cir. 1990) and MPEP 2144.05(III).
With respect to the limitation of the percentage range of the distance (d), it would have been obvious to one of ordinary skill in the art to have provided the apparatus defined by the disclosures of BORGSTROM et al. in view of HEINRICH with the configurations and/or dimensions recited in the claims which are considered at most optimum choices, lacking any disclosed criticality.
Applicant has the burden of proving such criticality. In re Swenson et al., 56 USPQ 372; In re Scherl, 70 USPQ 204. However, even though applicant's modification may result in great improvement and utility over the prior art, it may still not be patentable if the modification was within the capabilities of one skilled in the art. In re Sola, 25 USPQ 433; In re Normannet et al., 66 USPQ 308; In re Irmscher, 66 USPQ 314. More particularly, where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover optimum or workable ranges by routine experimentation. In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955); In re Swain et al., 70 USPQ 412; Minnesota Mining and Mfg. Co. v. Coe, 38 USPQ 213; Allen et al. v. Coe, 57 USPQ 136; MPEP 2144.05(II)(A). To adjust the percentage within the broad percentage range of the distance (d) through trial and error/experimentation to thereby achieve optimized separation performance by relying upon common sense, common knowledge generally, or common knowledge in the relevant art is deemed well within the capabilities of PHOSITA under 35 USC 103.
No probative evidence is of record to demonstrate that the dimensions and/or other variables of the invention are significant or are anything more than one of numerous dimensions a person of ordinary skill in the art would find obvious for purposes of merely changing the configurations and/or dimensions to obtain different results. Graham v. John Deere Co., 148 USPQ 459.
Accordingly, the examiner argues that these parameters are rather arbitrary and thus obvious over the prior art per MPEP 2144.05(II)(III).
Furthermore, the Federal Circuit has explained that a reason to optimize prior art parameters may be found in a PHOSITA’s desire to improve on the prior art. In re Ethicon, Inc., 844 F.3d 1344, 1351 (Fed. Cir. 2017) (‘‘The normal desire of artisans to improve upon what is already generally known can provide the motivation to optimize variables such as the percentage of a known polymer for use in a known device.’’).
The subject matter of the pending claims is deemed well within the grasp of 35 USC 103 since a PHOSITA would have been able to modify the percentage of the distance (d) of the elongated distribution part, with a reasonable expectation of success to be within the recited ranges, for the purpose of optimizing separation performance of one or more of the phases by moving the interface line therebetween radially inwardly into the disc stack within the centrifuge to a desired extent via the elongated or larger distribution part.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. The cited prior art discloses disc type centrifuges and distribution parts within such centrifuges.
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/CHARLES COOLEY/
Examiner, Art Unit 1774
DATED: 15 JULY 2026
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