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 .
Claim Objections
Claims 17–22 are objected to because of the following informalities. Each of claims 17 and 19–22 recites "The method according to claim 14," and claim 18 recites "The method according to claim 15," whereas claims 14 and 15 are directed to an installation and not to a method. From the subject matter recited, it appears that claims 17 and 19–22 were intended to depend from claim 16, and that claim 18 was intended to depend from claim 17. Appropriate correction is required. These claims are separately rejected under 35 U.S.C. §§ 112(b), 112(c) and 112(d) below.
Claims 17 and 19 are further objected to because they recite "CO2" in the body of the claim while the remainder of the claim set recites "CO₂." Consistent usage throughout the claim set is required. Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 15, 18 and 22 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
Claim 15 recites that “the first and second heat exchange coils are removably immersed within the tank to allow for maintenance of the coils and replacement of the liquid intermediary medium.” The specification as filed does not describe this subject matter. The specification describes a buffer tank C containing a liquid L and provided with two coils to enable heat exchange between the CO₂ and the liquid medium and between the refrigerant fluid and the liquid medium (¶¶ 0051–0055; fig. 1), and describes a 20-litre tank containing a refrigeration unit and a copper coil, together with a stainless-steel coil having an internal diameter of approximately 4 mm and a length of 10 m (¶¶ 0079–0080). Nowhere does the specification describe the coils as removable or removably immersed, nor does it describe maintenance of the coils, nor replacement of the liquid intermediary medium. The recitation therefore constitutes new matter. See MPEP §§ 2163 and 2163.06.
Claim 18 recites that “the volume of the liquid intermediary medium in the tank is in an amount to provide thermal inertia sufficient to reliquefy gas phase components accumulated in the second coil during a temporary stoppage of the user station.” The specification discloses a 20-litre tank (¶ 0079) and states that a bath temperature of 5 °C would enable the minimum exchange length to be reduced to approximately 1.5 m, which enables the flexible use of the liquefier thus dimensioned to liquefy any gas that has formed before the usage point (¶ 0082). The specification does not describe selecting or sizing the volume of the liquid intermediary medium by reference to a temporary stoppage of the user station, to the gas accumulated in the second coil during such a stoppage, or to any thermal inertia criterion. The recitation therefore constitutes new matter.
Claim 22 recites that “the liquefier is configured to output the pure liquid CO₂ stream at a temperature T(out) that is at least 2 °C higher than the temperature T(media) of the liquid intermediary medium.” The specification discloses a single set of operating conditions, in which the two-phase liquid-gas CO₂ enters at approximately 20 °C and leaves at approximately 12 °C while the water in the bath is set and held at a temperature of 10 °C, and states that care is taken to ensure that the output temperature of the CO₂ flow is slightly above the temperature of the cold fluid so as to prevent heat exchange pinch (¶¶ 0069–0074). The disclosure of this single working example does not describe the open-ended genus embraced by "at least 2 °C," which reads on temperature differences without any upper limit and which the specification elsewhere teaches away from, since an arbitrarily large approach temperature would defeat the stated objective of subcooling the CO₂ (¶¶ 0031, 0045). See MPEP § 2163(II)(A)(3)(a)(ii).
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 4–8 and 12–23 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 4 recites, in its final clause, that the second coil receives the two-phase CO₂ mixture to transfer heat to the cooled liquid intermediary medium, thereby re-liquefying gas phase components within the two-phase gas liquid mixture to form a pure liquid CO₂ stream "before the pure liquid CO₂ stream the compression means." A verb has been omitted between "the pure liquid CO₂ stream" and "the compression means," and it therefore cannot be determined what relationship between the stream and the compression means is required — whether the stream enters, reaches, is delivered to, or is acted upon by the compression means. For purposes of examination and of applying prior art, the clause is read as "before the pure liquid CO₂ stream enters the compression means."
Claims 4, 16, 21-23 recites the term "pure," as used in the recitations "a pure liquid CO₂ stream" and "said pure liquid CO₂ stream," is a relative term which renders the claims indefinite. The specification states that the invention relates to supplying a liquid referred to as "pure" or substantially pure, a notion said to be well known to the person skilled in the art (¶¶ 0005, 0030), and elsewhere equates the pure liquid with a liquid free of unwanted gas (¶ 0060). The specification thus indicates that a stream containing some residual gas phase may nevertheless fall within the term, but it does not provide a standard for ascertaining how much residual gas phase is permitted. One of ordinary skill in the art would not be reasonably apprised of the scope of the invention. See MPEP § 2173.05(b).
Claim 4 recites "a first heat exchange coil and a second heat exchange coil" and thereafter recites "the first coil" and "the second coil." There is insufficient antecedent basis for the limitations "the first coil" and "the second coil" in the claim. Consistent terminology is required.
Claim 5 further recites “the liquid CO2 is supplied at a pressure in the range of 50-60 bar,” but claim 4 does not establish clear antecedent basis for “the liquid CO2” as a distinct stream — it is unclear whether this refers to the liquid CO2 exiting the liquid CO2 source, the two-phase mixture entering the liquefier, or the pure liquid CO2 stream exiting the liquefier. Clarification is required.
Claim 8 recites that the second coil has an internal diameter of approximately 4 mm "to ensure turbulence and heat transfer efficiency." First, the term "approximately" is a relative term of degree, and the specification provides no standard for ascertaining the permitted deviation, reciting only the same term (¶¶ 0076, 0080). Second, whether flow within a tube is turbulent depends on the mass flow rate, density and viscosity of the fluid as well as on the internal diameter, as the specification itself acknowledges in applying the McAdams formula to a flow of D = 60 kg/h (¶¶ 0065, 0075–0076). It therefore cannot be determined whether a coil of a given internal diameter satisfies the functional requirement of the claim.
Claim 12 recites that the user station is a machining station utilizing "a high-pressure spray of liquid CO₂." The term "high-pressure" is a relative term. Claim 4, from which claim 12 depends, recites no pressure at all, and the pressure range by which the specification defines high-pressure CO₂ (¶¶ 0005, 0012) appears only in claim 5. The scope of claim 12 cannot be determined.
Claim 13 recites that the liquefier is configured to subcool the liquid CO₂ below its equilibrium temperature "at the supply pressure." There is insufficient antecedent basis for the limitation "the supply pressure" in the claim; claim 4, from which claim 13 depends, does not recite a supply pressure.
Claim 16 recites passing the flow of CO₂ through a liquefier "positioned proximate at an inlet of the compression means." The phrase "proximate at" is grammatically incomplete, and "proximate" is in any event a relative term of degree for which the specification supplies no standard, stating only that a liquefier is added to the inlet of the compressor so as to minimize the connection length between the liquefier and the compressor (¶ 0035). It cannot be determined how close to the inlet the liquefier must be positioned in order to fall within the claim.
Claims 17 and 19–22 recite "The method according to claim 14," and claim 18 recites "The method according to claim 15." Claims 14 and 15 are directed to an installation, not to a method. Because a method cannot be "according to" an installation, and because the claims do not identify which limitations of the referenced installation claim are intended to be carried into the method, the metes and bounds of claims 17–22 cannot be determined. For purposes of applying prior art, claims 17 and 19–22 are treated as depending from claim 16, and claim 18 is treated as depending from claim 17.
Claim 18 further recites that the volume of the liquid intermediary medium is in an amount to provide thermal inertia "sufficient" to reliquefy gas phase components accumulated in the second coil during a temporary stoppage of the user station. "Sufficient" is a relative term, and the claim recites no duration of stoppage, no rate of heat ingress, and no quantity of accumulated gas against which sufficiency could be measured. The scope of the claim cannot be determined.
Claim 19 is indefinite in that it recites “the refrigerant is selected from the group consisting of glycolated water and a network of iced water from the user source.” A Markush grouping must recite members of the same class (here, materials/refrigerants); “a network of iced water” describes a distribution system, not a species of refrigerant, so it is unclear what physical material is being claimed as the second group member (presumably “iced water”, with “from a network… of the user source” intended as a source-limitation rather than a compositional one). Clarification is required.
Claim 22 recites an output temperature T(out) at least 2 °C higher than the temperature T(media) of the liquid intermediary medium. The claim does not specify where or under what operating conditions either temperature is to be measured, for example, whether T(media) is measured at the inlet region or the outlet region of the bath, and whether the relationship must hold at steady state, at start-up, or during a stoppage. Because the temperature of a bath varies spatially and temporally during operation, it cannot be determined whether a given installation satisfies the limitation.
Claim 23 is directed to a process for supplying a user station with subcooled liquid CO₂ and recites, as its first step, "providing the installation as claimed in Claim 4." The claim thus recites both an apparatus and the process steps by which the apparatus is used, and it is unclear whether infringement occurs when one provides an installation meeting the limitations of claim 4, or only when the recited steps are actually performed using that installation. A claim of this hybrid form is indefinite. See MPEP § 2173.05(p)(II). For purposes of applying prior art, claim 23 is treated as a process claim requiring that the recited steps be performed using an installation meeting all of the limitations of claim 4.
Claims 6, 7, 9-11, 14 and 15 are also rejected under 35 U.S.C. 112(b) for being dependent upon a rejected claim.
The following is a quotation of 35 U.S.C. 112(d):
(d) REFERENCE IN DEPENDENT FORMS.—Subject to subsection (e), a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
The following is a quotation of pre-AIA 35 U.S.C. 112, fourth paragraph:
Subject to the following paragraph [i.e., the fifth paragraph of pre-AIA 35 U.S.C. 112], a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
Claims 17-22 are rejected under 35 U.S.C. 112(d) or pre-AIA 35 U.S.C. 112, 4th paragraph, as being of improper dependent form for failing to further limit the subject matter of the claim upon which it depends, or for failing to include all the limitations of the claim upon which it depends.
Claims 17 and 19–22 refer to claim 14 and claim 18 refers to claim 15. Claims 14 and 15 recite an installation; claims 17–22 recite method steps. A method claim referring to an installation claim does not incorporate and does not further limit the structural subject matter of that installation claim, and the resulting claim is broader in one respect and narrower in another than the claim to which it refers. See MPEP § 608.01(n)(III) (infringement test). Applicant may cancel the claim(s), amend the claim(s) to place the claim(s) in proper dependent form, rewrite the claim(s) in independent form, or present a sufficient showing that the dependent claim(s) complies with the statutory requirements.
Claim 18 is further improper because it recites "the volume of the liquid intermediary medium in the tank" and "the second coil." Neither a tank, nor a liquid intermediary medium, nor a second coil is recited in claim 15; these elements first appear, in the method claims, in claim 17. Applicant may cancel the claim(s), amend the claim(s) to place the claim(s) in proper dependent form, rewrite the claim(s) in independent form, or present a sufficient showing that the dependent claim(s) complies with the statutory requirements.
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 nonobviousness.
Claims 4, 6, 7, 10 and 13 are rejected under 35 U.S.C. § 103 as being unpatentable over Kora et al. (US 2022/0229024 A1) in view of Berwick (US 2,603,072), Goosmann (US 2,047,099) and Dewees et al. (US 5,267,455).
In regard to claim 4, Kora teaches an installation for the high-pressure supply of liquid CO₂ to a user station (liquid carbon dioxide supply device 100 supplying liquid carbon dioxide to supercritical fluid apparatus 200 including separation column 140) comprising:
a liquid CO₂ source (bottle 201 in which liquid carbon dioxide cooled to about 5 °C is stored as a mobile phase) and a compression means (parallel plunger pump 20 including pump heads 21, 22) disposed downstream the liquid CO₂ source (¶¶ 0011–0012, 0017, 0020, 0022; figs. 1, 2);
a liquefier (cooler 10 including heat exchanger 11) positioned at an inlet of the compression means (heat exchanger 11 provided in flow path 2 at a position farther upstream than pump 20) and configured to receive a flow of CO₂ from the liquid CO₂ source (flow path 2 connecting bottle 201 to mixer 120, the heat exchanger 11 and the pump 20 being provided in this order from an upstream portion toward a downstream portion of flow path 2) (¶¶ 0017, 0020; fig. 2);
wherein the liquefier comprises an enclosure containing an intermediary medium and a first heat exchange passage and a second heat exchange passage embedded therein (block 11a of cuboid shape containing parts of flow paths 1, 2, 3, the gaps among the flow paths being filled with metallic material 11b) (¶ 0018; fig. 2);
the first passage circulating a primary refrigerant from a refrigeration unit to cool the intermediary medium (flow path 1 provided while being wound in a coil shape in block 11a, through which compressor 12 circulates a refrigerant such as R-407C so that a refrigerant cycle is repeated and the inside of block 11a is cooled) (¶¶ 0018–0019; fig. 2); and
the second passage receiving the CO₂ flow to transfer heat to the cooled intermediary medium, thereby forming a liquid CO₂ stream of stabilized density before the stream reaches the compression means (flow path 2 provided in block 11a in a meander shape, heat being exchanged between flow path 1 and flow path 2 through metallic material 11b so that the liquid carbon dioxide supplied from bottle 201 is cooled and its density stabilized upstream of pump 20) (¶¶ 0020, 0028–0031; fig. 2).
Kora does not explicitly teach that the liquefier comprises a tank containing a liquid intermediary medium, with a first heat exchange coil and a second heat exchange coil immersed therein.
However, Berwick teaches a liquid cooling apparatus in which a tank contains a liquid intermediary medium (hermetically sealed cylindrical tank 1 adapted to contain brine) and in which a first heat exchange coil and a second heat exchange coil are immersed in that medium (two flat spiral coils 2 and 3 disposed in closely adjacent parallel positions within tank 1), the first coil circulating a primary refrigerant from a refrigeration unit to cool the liquid intermediary medium (coil 2 serving for the circulation of a liquefied gas refrigerant admitted through pipe 4 and expansion valve 5 and returned through pipe 8 to a condenser-compressor unit, the compressor driving motor being started and stopped by thermostat element 15 according to the thermal conditions prevailing within the tank), and the second coil receiving the fluid to be cooled so as to transfer heat to the cooled liquid intermediary medium (coil 3 serving for the passage of the fluid to be cooled, which enters through supply pipe 9 and leaves through delivery pipe 12) (col. 1–col. 2, description of the cooling unit of figs. 1–3; claims 1 and 3; figs. 1–3).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention, to modify the metal-filled block 11a of Kora by substituting it with a tank of liquid intermediary medium with two immersed coils as taught by Berwick, in order to obtain the predictable result of transferring cooling power from the refrigeration unit to the fluid to be cooled by way of a liquid intermediary, while gaining the thermal inertia of a liquid bath and the simplified construction and serviceability of coils immersed in a common tank.
Kora as modified does not explicitly teach that the flow of CO₂ received by the liquefier comprises a two-phase gas liquid mixture due to heat ingress in a fluid conduit between the liquid CO₂ source and the liquefier, nor that the second coil re-liquefies gas phase components within that mixture to form a pure liquid CO₂ stream.
However, Goosmann teaches providing a liquid cooler in which the liquid carbon dioxide is cooled while at the same time maintaining a higher pressure of the liquid, which thus becomes sub-cooled below the pressure at which it is maintained, whereby any gaseous bubbles in the liquid will be condensed and liquefied (col. 1, ll. 20–29). Goosmann further teaches carrying out such cooling in a coil immersed in a bath of cold liquid: inter-cooler 7 comprises a pipe coil immersed in cold water, or may have the form shown in fig. 4 so arranged that cold water may flow thereover, and liquid CO₂ may be used for cooling instead of water as for instance in liquid coolers 28 and 31 (col. 3, ll. 25–33); the same heat exchanger of fig. 4 is expressly stated to be adapted for use as an inter-cooler or a liquid cooler, the liquid to be cooled passing through tubes 108 while the cooling medium passes through the shell around the tubes, or the reverse (col. 5, l. 61 – col. 6, l. 7; fig. 4). Applicant's own specification likewise admits that, in installations of this type, the ingress of heat into the pipes connecting the liquid CO₂ source to the usage point is inevitable and unavoidably evaporates a portion of the cryogenic liquid, producing a gas/liquid mixture that reaches the compressor and would cause the compressor to malfunction (specification ¶¶ 0016–0021, 0034), which is prior art admitted by Applicant. See MPEP § 2129.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have arranged the coil-in-bath liquefier of Kora as modified by Berwick so as to receive the two-phase gas-liquid CO₂ flow arising from heat ingress and to re-condense the gaseous bubbles therein, as taught by Goosmann, in order to deliver a pure liquid stream to the pump (see Goosmann col. 1, ll. 20–29).
Kora as modified does not explicitly teach that the pure liquid CO₂ stream is formed before the stream enters the compression means for the purpose of protecting that compression means.
However, Dewees teaches a liquid CO₂ supply installation in which liquid CO₂ is pumped from a storage vessel to a user station by a piston pump, and in which a subcooler positioned in the conduit between the storage vessel and the pump lowers the temperature of the CO₂ by 2 ° to 3 ° below the boiling point to prevent pump cavitation (storage vessel 12 in which liquid CO₂ is stored at approximately 915 psi and 25 °C, pump 20 preferably having dual pistons with either direct or hydraulic/electric drive, and subcooler 30) (Description of the Preferred Embodiment, discussion of fig. 1; col. 3, ln 1-18; claims 1–3; fig. 1).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have located the modified liquefier of Kora so that the pure liquid CO₂ stream is formed before the stream enters the compression means, as taught by Dewees, in order to prevent cavitation and consequent malfunction or damage of the pump. Dewees expressly identifies this benefit, and claims the arrangement as cooling means disposed in the conduit means for cooling the fluid from the storage vessel below its boiling point (col. 3, ln 19-40; claim 3).
In regard to claim 6, Kora as modified teaches the installation according to claim 4 wherein the liquid intermediary medium in the tank is selected from the group consisting of water and glycolated water (Goosmann: inter-cooler 7 comprising a pipe coil immersed in cold water, cold water likewise being the cooling medium flowing over the exchanger of fig. 4 (col. 3, ll. 25–33); Kora: storage 13 storing a refrigerant such as ethylene glycol having a concentration of 60 %, circulated by liquid sender 14 through flow path 3 and cooled in block 11a (¶¶ 0018, 0021, 0023; fig. 2)).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have selected water or glycolated water as the liquid intermediary medium of the tank, since Goosmann teaches cold water as the cooling medium for the CO₂ coil and Kora already employs 60 % ethylene glycol — that is, glycolated water — as the intermediary heat-transfer liquid in the same installation, and since the selection of a known material on the basis of its suitability for its intended use is within the ordinary skill in the art. See In re Leshin, 277 F.2d 197 (CCPA 1960); MPEP § 2144.07.
In regard to claim 7, Kora as modified teaches the installation according to claim 4 wherein the refrigeration unit is configured to maintain the liquid intermediary medium at a temperature within a range (Kora: flow path 1 cooled to about −30 °C and flow paths 2 and 3 cooled to about −10 °C in heat exchanger 11, with heaters 15, 16, temperature sensor 4 and controller 170 operated so that the liquid carbon dioxide in flow path 2 and the pump heads 21, 22 are held at about 5 °C; Berwick: thermostat element 15 sealed in socket 16 within tank 1 and connected through capillary tube 17 to a thermostat component that starts or stops the compressor driving motor according to the thermal conditions prevailing within the tank) (Kora ¶¶ 0012, 0024–0027, 0030; fig. 2; Berwick, col. 2, description of thermostat element 15; fig. 2).
Kora as modified does not explicitly teach that the temperature maintained is within a range of 5 °C to 15 °C. However, the temperature of the intermediary bath is a result-effective variable: it determines the degree of subcooling achieved and hence the recondensation of gas bubbles, while a bath temperature that is too low risks freezing an aqueous medium and one that is too high fails to condense the gas phase. Kora already establishes 5 °C as the target temperature for the liquid carbon dioxide entering the pump (¶¶ 0012, 0024).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have determined the optimum or workable bath temperature, including a range of 5 °C to 15 °C, through routine experimentation, in order to achieve sufficient subcooling of the CO₂ without freezing the aqueous intermediary medium. Where 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 In re Aller, 220 F.2d 454, 456 (CCPA 1955); MPEP § 2144.05(II).
In regard to claim 10, Kora as modified teaches the installation according to claim 4 wherein the compression means comprises a piston compressor (Kora: pump 20 being a parallel plunger pump including pump heads 21, 22 which alternately pump the liquid carbon dioxide stored in bottle 201 through cooler 10 to mixer 120; Dewees: pump 21 being a direct drive, single-piston pump and pump 20 preferably having dual pistons with either direct or hydraulic/electric drive) (Kora ¶¶ 0017, 0022; fig. 2; Dewees, col. 3, ln 2-30; fig. 1). Applicant's specification further admits that the pressurization of liquid CO₂ for this application is often carried out using volumetric pumps, referred to as cryogenic pumps, which are based on pistons (¶ 0014).
In regard to claim 13, Kora as modified teaches the installation according to claim 4 wherein the liquefier is configured to subcool the liquid CO₂ below its equilibrium temperature at the supply pressure (Goosmann: liquid carbon dioxide cooled while a higher pressure of the liquid is maintained, whereby the liquid becomes sub-cooled below the pressure at which it is maintained and any gaseous bubbles in the liquid are condensed and liquefied (col. 1, ll. 20–29); Dewees: subcooler 30 lowering the temperature of the CO₂ by 2 ° to 3 ° below the boiling point to prevent pump cavitation, claimed as cooling means disposed in the conduit means for cooling the fluid from the storage vessel below its boiling point (col. 3, ll. 31-40; fig. 1)).
Claims 5, 11 and 16–23 are rejected under 35 U.S.C. § 103 as being unpatentable over Kora in view of Berwick, Goosmann, Dewees and AAPA as applied to claim 4 above, and further in view of Pereira Neto et al. (US 2019/0160618 A1).
In regard to claim 5, Kora as modified teaches the installation according to claim 4 wherein the liquid CO₂ is supplied at a pressure in the range of 50-60 bar (Applicant Admitted Prior Art: liquid CO₂ most frequently stored at 45-55 bar absolute at ambient temperature in an ambient-temperature storage facility, high-pressure liquid CO₂ being obtained by increasing the pressure of the cryogenic liquid to a pressure below but relatively close to the critical point, 50 to 60 bar for example, and supplied to the user station at approximately 50-60 bar (specification ¶¶ 0005, 0010, 0012); Pereira Neto: CO₂ in liquid state in channel "b" at a pressure of around 50-60 bar, that is, 5.0-6.0 MPa, supplied through coupling 1 from a bottle of CO₂ in liquid state (¶¶ 0051, 0055, 0066; fig. 3)). See MPEP § 2129.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have supplied the liquid CO₂ of Kora as modified at a pressure in the range of 50-60 bar, as Applicant admits was conventional for high-pressure liquid CO₂ service and as Pereira Neto corroborates, in order to deliver the liquid at the pressure ordinarily available from an ambient-temperature liquid CO₂ storage facility and required at the user station, and so as to remain below but near the critical point of CO₂ as the admitted prior art teaches. Where the claimed range and the range disclosed in the prior art are substantially identical, a prima facie case of obviousness exists. See MPEP § 2144.05(I).
In regard to claim 11, Kora as modified teaches the installation according to claim 4 further comprising a non-return valve positioned between the liquid CO₂ source and the liquefier (Pereira Neto: first no-return valve 15 disposed to communicate conduit "a", which is fed with CO₂ in liquid state through entry 1, with conduit "b", so that when solenoid valve 7 is closed flow is allowed from conduit "b" towards conduit "a" but not the other way around) (¶¶ 0020, 0051, 0054, 0058; fig. 3).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have positioned a non-return valve between the modified liquid CO₂ source and the liquefier of Kora, as taught by Pereira Neto, in order to prevent back-flow of fluid toward the source.
In regard to claim 16, Kora teaches a method for supplying a user station with high-pressure liquid CO₂ (method of operating liquid carbon dioxide supply device 100 to supply liquid carbon dioxide to supercritical fluid apparatus 200 including separation column 140) comprising:
providing a flow of CO₂ from a liquid source toward a compression means (liquid carbon dioxide drawn from bottle 201 and conveyed along flow path 2 toward parallel plunger pump 20) (¶¶ 0012, 0017, 0020, 0022; figs. 1, 2);
passing the flow of CO₂ through a liquefier positioned proximate at an inlet of the compression means (flow path 2 passing through heat exchanger 11 of cooler 10, which is provided at a position farther upstream than pump 20, with heater 15 and temperature sensor 4 disposed on the portion of flow path 2 drawn out from block 11a and controlled so that the temperature of the liquid carbon dioxide is not changed by outside air over the portion of flow path 2 from heat exchanger 11 to pump 20) (¶¶ 0017, 0020, 0025–0026, 0030–0031; fig. 2);
cooling the flow of CO₂ within the liquefier to form a liquid CO₂ stream of stabilized density (heat exchanged between flow path 1 and flow path 2 through metallic material 11b in block 11a, whereby the liquid carbon dioxide is cooled directly, its temperature and hence its density are stabilized, and it is supplied at a stable flow rate) (¶¶ 0018, 0020, 0028–0029; fig. 2); and
compressing the liquid CO₂ stream and conveying said stream to the user station at a pressure (pump 20 pumping the cooled liquid carbon dioxide through mixer 120 and sample supplier 130 to separation column 140, back-pressure valve 160 keeping the pressure applied to the mobile phase at a value equal to or larger than the critical pressure of liquid carbon dioxide) (¶¶ 0013–0015, 0022; figs. 1, 2).
Kora does not explicitly teach re-liquefying any gas phase components generated within the flow of CO₂ to form a pure liquid CO₂ stream, nor conveying the pure liquid CO₂ stream to the user station at a pressure in a range of 50-60 bar.
However, Goosmann teaches cooling liquid carbon dioxide while at the same time maintaining a higher pressure of the liquid, which thus becomes sub-cooled below the pressure at which it is maintained, whereby any gaseous bubbles in the liquid will be condensed and liquefied (col. 1, ll. 20–29), and teaches carrying out such cooling in a coil immersed in a bath of cold liquid (col. 3, ll. 25–33; col. 5, l. 61 – col. 6, l. 7; fig. 4).
Applicant further admits that the means most frequently used to convey liquid CO₂ from the storage facility to the usage point comprise a first step of increasing the pressure of the cryogenic liquid to a pressure below the critical point of CO₂ but relatively close to that point, 50 to 60 bar for example, that liquid at that pressure is referred to as high-pressure liquid CO₂, and that a second step then reaches the target pressure required at the usage point (specification ¶¶ 0011–0013; see also ¶ 0005, describing the object of supplying a user station with pure or substantially pure liquid CO₂ typically at approximately 50-60 bar). This is prior art admitted by Applicant. See MPEP § 2129. Pereira Neto corroborates that liquid CO₂ is conventionally handled in such installations at a pressure of around 50-60 bar, that is, 5.0-6.0 MPa (conduit "b" downstream of solenoid valve 7) (¶¶ 0051, 0066; fig. 3).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have re-liquefied the gas phase generated in the CO₂ flow within the liquefier of Kora, as taught by Goosmann, and to have compressed the resulting pure liquid CO₂ stream to a pressure in the range of 50-60 bar for delivery to the user station, as Applicant admits was the conventional first compression step in installations of this type, in order to deliver to the user station a liquid free of the gas cushions that disturb metering and damage the pump, and to do so at the pressure conventionally required for high-pressure liquid CO₂ service. Where the claimed range and the range disclosed in the prior art are substantially identical, a prima facie case of obviousness exists. See MPEP § 2144.05(I). The motivation to combine is further supplied by Applicant's admission that the gas resulting from evaporation of the liquid CO₂ will inevitably move towards the user application and will be pumped by the pump, disturbing operation of the pumps or damaging these pumps (¶¶ 0018, 0034).
In regard to claim 17, Kora as modified teaches the method according to claim 16 wherein the liquefier comprises a tank containing a volume of a liquid intermediary medium and first and second heat exchange coils immersed therein, wherein the step of cooling the flow of CO₂ comprises introducing the flow of CO₂ into the second heat exchange coil and exchanging heat with the liquid intermediary medium within the tank, and wherein the liquid intermediary medium within the tank is maintained at a temperature by circulating a refrigerant through the first heat exchange coil immersed in the liquid intermediary medium (Berwick: sealed tank 1 containing brine with spiral coils 2 and 3 immersed therein, coil 2 circulating refrigerant from the condenser-compressor unit and coil 3 passing the fluid to be cooled, the temperature within the tank being maintained by thermostat element 15 which starts and stops the compressor driving motor; Kora: flow path 2 passing through the heat exchanger and cooled by the refrigerant circulated by compressor 12) (Berwick, col. 1–col. 2; claims 1 and 3; figs. 1–3; Kora ¶¶ 0018–0020, 0024; fig. 2).
Kora as modified does not explicitly teach that the liquid intermediary medium is maintained at a temperature between 5 °C and 15 °C.
However, the temperature of the intermediary bath is a result-effective variable: it governs the degree of subcooling imparted to the CO₂ and hence the recondensation of the gas phase, while a bath temperature that is too low risks freezing an aqueous medium and one that is too high fails to condense the gas. Kora establishes 5 °C as the target temperature of the liquid carbon dioxide delivered to the pump, and Berwick maintains the temperature within its brine tank by a thermostat element that starts and stops the compressor driving motor according to the thermal conditions prevailing within the tank (Kora ¶¶ 0012, 0024–0027; Berwick, col. 1–col. 2; figs. 1–3).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have carried out the cooling step of the method in a tank containing a liquid intermediary medium with the CO₂ coil and the refrigerant coil immersed therein, as taught by Berwick, in order to convey the cooling power generated by the refrigeration unit to the CO₂ flow by way of a liquid intermediary while gaining the thermal inertia of a liquid bath and the simplified construction of two coils immersed in a common tank, this being the simple substitution of one known heat-exchanger construction for another to obtain predictable results, and to have determined the optimum or workable bath temperature, including a range of 5 °C to 15 °C, through routine experimentation, in order to achieve sufficient subcooling of the CO₂ without freezing the aqueous intermediary medium. See KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 416 (2007); MPEP § 2143(I)(B); In re Aller, 220 F.2d 454, 456 (CCPA 1955); MPEP § 2144.05(II).
In regard to claim 18, Kora as modified teaches the method according to claim 17 wherein the volume of the liquid intermediary medium in the tank is in an amount to provide thermal inertia (Berwick: tank 1 whose volume approximates as closely as possible to the space occupied by the two coils for the purpose of reducing the quantity of brine employed to the minimum, the apparatus being capable of very rapidly adjusting itself to a predetermined temperature level irrespective of the quantity of liquid passed through it during any one operation or series of operations) (col. 1; col. 2; figs. 1–3).
Kora as modified does not explicitly teach that the volume is sufficient to reliquefy gas phase components accumulated in the second coil during a temporary stoppage of the user station.
However, the volume of the intermediary bath is a result-effective variable: a larger volume stores more cold and therefore sustains condensation of gas for a longer interruption in flow, while a smaller volume reduces the size, cost and cool-down time of the unit, as Berwick expressly recognizes in minimizing the quantity of brine while retaining rapid self-adjustment to a predetermined temperature level (col. 1).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have determined the optimum or workable volume of the liquid intermediary medium, including a volume sufficient to reliquefy the gas accumulated during a temporary stoppage of the user station, through routine experimentation, in order to maintain the supply of pure liquid across the intermittent operation acknowledged in Applicant's admitted prior art (¶¶ 0016–0021). See In re Aller, 220 F.2d at 456; MPEP § 2144.05(II).
In regard to claim 19, Kora as modified teaches the method according to claim 16 wherein the liquefier comprises a heat exchanger configured to provide direct heat transfer between the flow of CO₂ and a refrigerant, wherein the refrigerant is selected from the group consisting of glycolated water and a network of iced water (Kora: heat exchanger 11 in which heat is exchanged between flow path 1 and flow path 2 and between flow path 1 and flow path 3, flow path 3 circulating a refrigerant such as ethylene glycol having a concentration of 60 % stored in storage 13 and pumped by liquid sender 14) (¶¶ 0018, 0020–0021, 0023, 0047–0048; fig. 2).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have placed the glycolated water already circulated in Kora's installation in direct heat exchange with the CO₂ flow path, since Kora discloses a single heat exchanger 11 in which all three flow paths are placed in mutual heat exchange through the metallic material (¶¶ 0018, 0020–0021), and since the rearrangement of known heat-exchange passages to place two of them in direct exchange is a predictable variation yielding no more than the expected result of cooling the CO₂. See MPEP § 2143(I)(A) and (I)(D).
In regard to claim 20, Kora as modified teaches the method according to claim 16 wherein parasitic gas bubbles formed by heat ingress in a supply line during a stoppage of the user station are condensed within the liquefier (Goosmann: liquid carbon dioxide sub-cooled below the pressure at which it is maintained, whereby any gaseous bubbles in the liquid will be condensed and liquefied) (col. 1, ll. 20–29). Applicant's specification admits that, during a stoppage of variable duration of the final application, a part of the liquid trapped in the pipes may evaporate, this being caused by the ingress of heat between the liquid source and its usage point, in the connection pipes of the different equipment used for implementation, and that the ingress of heat into pipes that are not usually insulated is inevitable and cannot be prevented or avoided (¶¶ 0016–0017, 0021), which is prior art admitted by Applicant.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have condensed within the liquefier of Kora as modified the parasitic gas bubbles formed by heat ingress in the supply line during a stoppage of the user station, as taught by Goosmann, in order to restore a pure liquid stream upon resumption of usage and to prevent that gas from reaching and disturbing the compression means.
In regard to claim 21, Kora itself teaches the method according to claim 16 wherein the pure liquid CO₂ stream is compressed to a supercritical state, so that no further modification of the combination is required, namely that the stream is compressed to a supercritical state after exiting the liquefier and before reaching the user station (Kora: separation column 140 heated in a column oven to a predetermined temperature of about 40 °C and back-pressure valve 160 keeping the pressure applied to the mobile phase at a value equal to or larger than the critical pressure of liquid carbon dioxide, for example 8 MPa, such that the liquid carbon dioxide in the mobile phase is put in a supercritical state at least in the separation column 140, the mobile phase being pumped there by pump 20 downstream of cooler 10) (¶¶ 0014–0015, 0020, 0022; figs. 1, 2). Applicant's specification further admits that numerous industrial applications require high-pressure CO₂, notably including all supercritical CO₂ applications beyond the critical point of CO₂ of approximately 32 °C and 74 bar, and that the end user reaches the usage conditions beyond the critical point in a single compression stage (¶¶ 0006, 0024), which is prior art admitted by Applicant.
In regard to claim 22, Kora as modified teaches the method according to claim 16 wherein the liquefier outputs the liquid CO₂ stream at a temperature T(out) that differs from the temperature T(media) of the liquid intermediary medium (Kora: flow paths 2 and 3 cooled to about −10 °C within block 11a while the liquid carbon dioxide flowing through flow path 2 is held at about 5 °C by heater 15 under control of temperature sensor 4 and controller 170; Berwick: the incoming warm fluid in coil 3 being juxtaposed to the incoming refrigerant in coil 2 so as to initiate quick cooling, the outlet fluid leaving the coil after traversing the bath) (Kora ¶¶ 0024–0027, 0030; fig. 2; Berwick, col. 1; col. 2; figs. 1–3).
Kora as modified does not explicitly teach that T(out) is at least 2 °C higher than T(media) to prevent heat exchange pinch.
However, the approach temperature between the two streams of a counter-current heat exchanger is a result-effective variable and is inherent to the operation of any such exchanger: the outlet temperature of the warm stream can never fall below the temperature of the cold stream, and the smaller the approach, the larger the exchange area required, as is well understood from the logarithmic mean temperature difference relied upon in Applicant's own analysis (¶¶ 0073–0077).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have determined the optimum or workable approach temperature between the CO₂ outlet and the intermediary medium, including a difference of at least 2 °C, through routine experimentation, in order to size the exchange coil economically while avoiding a temperature pinch. See MPEP § 2144.05(II).
In regard to claim 23, Kora as modified teaches a process for supplying a user station with subcooled liquid CO₂, at a pressure in the range from 50 to 60 bar, from a source of liquid CO₂, the process comprising the steps of:
providing the installation as claimed in claim 4 (Kora: liquid carbon dioxide supply device 100 having bottle 201, cooler 10 including heat exchanger 11 provided farther upstream than parallel plunger pump 20, and compressor 12 circulating a refrigerant through flow path 1 to cool the intermediary medium 11b (¶¶ 0011–0012, 0017–0020, 0022; fig. 2); Berwick: sealed tank 1 containing brine with spiral coils 2 and 3 immersed therein, coil 2 circulating refrigerant from the condenser-compressor unit through expansion valve 5 and coil 3 passing the fluid to be cooled (col. 1–col. 2; claims 1 and 3; figs. 1–3));
introducing the flow of CO₂ from the liquid CO₂ source to the liquefier, wherein the flow of CO₂ comprises the two-phase gas liquid mixture due to heat ingress in a fluid conduit between the liquid CO₂ source and the liquefier (Kora: liquid carbon dioxide drawn from bottle 201 into flow path 2 and thence into heat exchanger 11 upstream of pump 20 (¶¶ 0012, 0017, 0020; fig. 2); Applicant's admitted prior art: heat ingress into the uninsulated connection pipes between the liquid source and the usage point inevitably evaporating a part of the liquid so that a gas/liquid mixture reaches the compressor (¶¶ 0016–0021, 0034));
reliquefying gas phase components of the two-phase gas liquid mixture within the liquefier, thereby forming the pure liquid CO₂ stream (Goosmann: the liquid becoming sub-cooled below the pressure at which it is maintained, whereby any gaseous bubbles in the liquid will be condensed and liquefied) (col. 1, ll. 20–29);
introducing the pure liquid CO₂ stream to the compression means without allowing for formation of gas bubbles within the pure liquid CO₂ stream between the liquefier and the compression means (Kora: heater 15 attached to the portion of flow path 2 drawn out from block 11a and temperature sensor 4 attached at a position farther downstream than heater 15, controlled by controller 170 so that the temperature of the liquid carbon dioxide flowing through flow path 2 is kept at the desired value notwithstanding the effect of outside air in the portion of flow path 2 from heat exchanger 11 to pump 20) (¶¶ 0025–0026, 0030–0031; fig. 2; Dewees: subcooler 30 cooling the CO₂ by 2 ° to 3 ° below its boiling point to prevent pump cavitation, claimed as cooling means disposed in the conduit means for cooling the fluid from the storage vessel below its boiling point (col. 3, ll. 1-40; fig. 1)); and
transferring the pure liquid CO₂ stream from the compression means to the user station at a pressure in the range from 50 to 60 bar (Kora: pump 20 supplying the liquid carbon dioxide through mixer 120 and sample supplier 130 to separation column 140 (¶¶ 0013–0014, 0022; figs. 1, 2); Applicant Admitted Prior Art: a first step of increasing the pressure of the cryogenic liquid to a pressure below the critical point of CO₂ but relatively close to that point, 50 to 60 bar for example, that liquid being referred to as high-pressure liquid CO₂ (specification ¶¶ 0005, 0011–0013); Pereira Neto: CO₂ in liquid state at a pressure of around 50-60 bar, that is 5.0-6.0 MPa (¶¶ 0051, 0066; fig. 3)).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have carried out the recited process using the installation of Kora as modified, in which the CO₂ coil and the refrigerant coil are immersed in a tank of liquid intermediary medium as taught by Berwick, in order to convey the cooling power of the refrigeration unit to the CO₂ by way of a liquid intermediary of substantial thermal inertia; to have subcooled the flow so that the gaseous bubbles carried in it are condensed and liquefied, as taught by Goosmann, in order to deliver a liquid free of gas to the downstream equipment; to have formed that pure liquid stream immediately upstream of the compression means and held it free of gas over the intervening run, as taught by Dewees and by Kora's control of the pipe portion between the heat exchanger and the pump, in order to prevent cavitation and consequent malfunction or damage of the pump; and to have delivered the stream to the user station at 50 to 60 bar, as Applicant admits was the conventional first compression step for high-pressure liquid CO₂ service and as Pereira Neto corroborates. See MPEP §§ 2143(I)(A) and (I)(B), 2144.05(I), 2129.
Claim 12 is rejected under 35 U.S.C. § 103 as being unpatentable over Kora in view of Berwick, Goosmann, Dewees and AAPA as applied to claim 4 above, and further in view of Pereira Neto and Kowalewski (US 2016/0053943 A1).
In regard to claim 12, Kora as modified teaches the installation according to claim 4 wherein the user station is a machining station utilizing a high-pressure spray of liquid CO₂ (Pereira Neto: device 100 for cooling and lubricating a tool during a chip removal machining process, in which the first subsystem 110 supplies CO₂ in liquid state through exit coupling 18 to a hose terminating in a nozzle 185 that externally cools the part being machined, or alternatively to an internal channel of the cutting tool from which the liquid CO₂ exits through openings 300; Kowalewski: facility for supplying at least one station P, P1, P2 carrying out machining operations with subcooled cryogenic liquid, in which the higher the spraying pressure in the machining zone the better the heat exchange coefficients, and in which a heat exchanger submerged in a bath 20 is provided and the cryogenic liquid originating from the storage tank is made to pass through that exchanger before it arrives at the machining station) (Pereira Neto ¶¶ 0004–0005, 0014–0016, 0049–0050; figs. 3, 6, 7; Kowalewski ¶¶ 0002, 0011–0012, 0025–0029, 0047, 0049; claims 6 and 7; figs. 1–3).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have employed the liquid CO₂ supply installation of Kora as modified to supply a machining station utilizing a high-pressure spray of liquid CO₂, as taught by Pereira Neto and Kowalewski, because both references identify machining as an application requiring a supply of pure or subcooled cryogenic liquid at elevated pressure, and because the substitution of one known user station for another to obtain the predictable result of delivering pure liquid CO₂ to the point of use is within the ordinary skill in the art. See MPEP § 2143(I)(B). Applicant's specification further admits that the machining of metal parts under a liquid cryogen spray is a known application in which the higher the spraying pressure in the machining zone, the better the coefficients of heat exchange (¶¶ 0003–0005).
Claims 8, 9 and 14 are rejected under 35 U.S.C. § 103 as being unpatentable over Kora in view of Berwick, Goosmann, Dewees and AAPA as applied to claim 4 above, and further in view of Howard (US 4,590,770).
In regard to claim 8, Kora as modified teaches the installation according to claim 4 wherein the second coil has an internal diameter (Howard: coil of tubing 17 of 9.5 mm copper tubing immersed in the water within housing chamber 10, its ends silver brazed into counter-bored bushings 13–16) (Howard, col. 2, EXAMPLE; figs. 1, 2).
Kora as modified does not explicitly teach that the internal diameter is approximately 4 mm to ensure turbulence and heat transfer efficiency.
However, the internal diameter of a heat-exchange tube is a result-effective variable: for a given mass flow rate, reducing the internal diameter increases the fluid velocity and hence the Reynolds number and the convective heat transfer coefficient, while increasing the pressure drop through the coil. Applicant's own specification confirms that the skilled artisan arrives at the diameter by applying the known McAdams formula for a tube with turbulence having a constant external wall temperature (¶¶ 0075–0076).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have determined the optimum or workable internal diameter of the coil, including approximately 4 mm, through routine experimentation, in order to achieve turbulent flow and thus efficient heat transfer at the design flow rate. See In re Aller, 220 F.2d at 456; MPEP § 2144.05(II). A change in the size or proportion of a prior art component, without more, is likewise not sufficient to patentably distinguish over the prior art. See Gardner v. TEC Systems, Inc., 725 F.2d 1338 (Fed. Cir. 1984); MPEP § 2144.04(IV)(A).
In regard to claim 9, Kora as modified teaches the installation according to claim 4 wherein the second coil has a length of at least 2.2 m (Howard: coil of tubing 17 joined between ports 15 and 16 and located inside housing chamber 10 so as to be immersed in the water therein, the tubing 17 being made up of a 15.24 meter length of 9.5 mm copper tubing coiled to an outside diameter of about 15 cm) (col. 1, SUMMARY OF THE INVENTION; col. 2, EXAMPLE; claims 1–3; figs. 1, 2).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have provided the CO₂ coil of Kora as modified with a length of at least 2.2 m, as taught by Howard, in order to provide sufficient heat-exchange area between the coil and the surrounding water bath. Where the prior art range encompasses the claimed range, a prima facie case of obviousness exists. See MPEP § 2144.05(I).
In regard to claim 14, Kora as modified teaches the installation according to claim 4 wherein a heat exchange coil immersed in the liquid intermediary medium comprises copper and a component of the exchanger in contact with the pressurized fluid comprises stainless steel (Howard: housing chamber 10 created from 4.75 mm alloy 304 stainless steel with the coil of tubing 17 immersed therein being made up of 9.5 mm copper tubing, and stainless steel bushings 13–16 welded to plate 12; Dewees: storage vessel 12 for the liquid CO₂ preferably made of stainless steel, and the vessels of the system generally made from materials chemically compatible with the dense fluids used and sufficiently strong to withstand the pressures necessary to carry out the process, such as stainless steel) (Howard, col. 2, EXAMPLE; claim 3; figs. 1, 2; Dewees, Description of the Preferred Embodiment, discussion of figs. 1 and 2).
Kora as modified does not explicitly teach that the first heat exchange coil comprises copper and the second heat exchange coil comprises stainless steel.
However, Howard teaches copper tubing for a heat exchange coil immersed in a water bath, and Dewees teaches stainless steel for the components of a liquid CO₂ system that must be chemically compatible with the dense fluid and strong enough to withstand its operating pressure.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have formed the refrigerant coil of copper, as taught by Howard, for its high thermal conductivity and ease of forming into a coil, and to have formed the CO₂ coil of stainless steel, as taught by Dewees, so that it would be chemically compatible with the CO₂ and able to withstand the elevated supply pressure. The selection of a known material on the basis of its suitability for the intended use is within the ordinary skill in the art. See MPEP § 2144.07.
Claim 15 is rejected under 35 U.S.C. § 103 as being unpatentable over Kora in view of Berwick, Goosmann, Dewees and AAPA as applied to claim 4 above, and further in view of Villarreal (US 2016/0169450 A1).
In regard to claim 15, Kora as modified teaches the installation according to claim 4 wherein the first and second heat exchange coils are immersed within the tank (Berwick: spiral coils 2 and 3 disposed in closely parallel positions within the brine tank 1 after installation of which the tank is filled with brine and hermetically sealed) (col. 1–col. 2; claims 1 and 3; figs. 1–3).
Kora as modified does not explicitly teach that the coils are removably immersed within the tank to allow for maintenance of the coils and replacement of the liquid intermediary medium.
However, Villarreal teaches that components immersed within a vessel of a cryogenic product installation should be made accessible for installation and maintenance without dismantling the vessel assembly, and teaches providing a manway designed and built into the product storing vessel through which the immersed pump may be accessed for mounting and maintenance, expressly identifying the lack of quick and easy access to immersed components for installation and maintenance as a problem of the prior art and convenient access for maintenance as an advantage of the disclosed arrangement (¶¶ 0007, 0025, 0030; figs. 4–6).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have mounted the two coils of Kora as modified so that they are removably immersed within the tank, as suggested by Villarreal, in order to permit servicing of the coils and replacement of the bath liquid without discarding the tank. Constructing a formerly integral or permanently installed structure in separable or removable form is a matter of obvious engineering choice where separability is desirable for servicing. See MPEP § 2144.04(V)(C). The desirability of such servicing is confirmed by Berwick itself, which seals the tank specifically to exclude air that would otherwise tend to promote corrosion of the coils (col. 1).
Response to Arguments
Applicant's arguments with respect to the amended claims have been fully considered but are moot in view of the new grounds of rejection set forth above.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/W.M/Examiner, Art Unit 3763
/FRANTZ F JULES/Supervisory Patent Examiner, Art Unit 3763
