Prosecution Insights
Last updated: October 25, 2026
Application No. 18/563,616

METHOD AND SYSTEM FOR AVOIDING FREEZING OF AT LEAST ONE COMPONENT OF A CRYOGENIC FLUID INSIDE A CRYOGENIC HEAT EXCHANGER

Final Rejection §103§112
Filed
Nov 22, 2023
Priority
Jun 21, 2021 — EU 21315097.2 +1 more
Examiner
PETTITT, JOHN F
Art Unit
3763
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Cryostar SAS
OA Round
2 (Final)
26%
Grant Probability
At Risk
3-4
OA Rounds
1y 10m
Est. Remaining
48%
With Interview

Examiner Intelligence

Grants only 26% of cases
26%
Career Allowance Rate
181 granted / 700 resolved
-44.1% vs TC avg
Strong +22% interview lift
Without
With
+21.6%
Interview Lift
resolved cases with interview
Typical timeline
4y 9m
Avg Prosecution
64 currently pending
Career history
793
Total Applications
across all art units

Statute-Specific Performance

§101
0.2%
-39.8% vs TC avg
§103
44.4%
+4.4% vs TC avg
§102
18.3%
-21.7% vs TC avg
§112
35.9%
-4.1% vs TC avg
Black line = Tech Center average estimate • Based on career data from 700 resolved cases

Office Action

§103 §112
DETAILED ACTION The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Examiner Request The applicant is requested to provide line numbers to each claim in all future claim submissions to aide in examination and communication with the applicant about claim recitations. The applicant is thanked for aiding examination. 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. Claim(s) 1-5, 7, 13 is/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. In regard to claim 1, the recitation, “determining, by the computing means, if there is the risk of freezing of the at least one component of the cryogenic liquid stream inside the cryogenic heat exchanger based on the transmitted measurement and a temperature of the first refrigerant stream entering the cryogenic heat exchanger;” introduces new matter as there is no support for this step in the disclosure. See that the computing means is never disclosed as determining the risk of the freezing based on a temperature of the first refrigerant stream. 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. Claim(s) 1-5, 7, 13 is/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 pre-AIA the applicant regards as the invention. In regard to claim 1, the recitation, “to indirectly exchange heat with the cryogenic liquid stream” (line 5) is indefinite for improperly reintroducing indirectly exchanging heat anew when such was already previously introduced and it is unclear if this is the same heat exchange or not. The recitation, “being an indirect indicator of the risk of freezing” is indefinite for improperly reintroducing anew “freezing” and it is unclear if this is the same or other freezing. Further, the recitation is indefinite since it is not clear what makes a property an “indirect indicator of” a risk of the freezing, since it is unclear what properties are included and excluded. The specification has attempted to redefine the recited term, “physical property”, (spec. page. 3-4) contrary to the general excepted meaning. Where applicant acts as his or her own lexicographer to specifically define a term of a claim contrary to its ordinary meaning, the written description must clearly redefine the claim term and set forth the uncommon definition so as to put one reasonably skilled in the art on notice that the applicant intended to so redefine that claim term. Process Control Corp. v. HydReclaim Corp., 190 F.3d 1350, 1357, 52 USPQ2d 1029, 1033 (Fed. Cir. 1999). The term “physical property” in claim 1 is used by the claim to mean “a property for the measurement of which an exhaustive determination of the chemical composition of the fluid is not necessary” (spec. page 3-4), while the accepted meaning is “a characteristic of matter” which is far ranging and very inclusive. The term is indefinite because the specification does not clearly redefine the term. The lack of clarity of the redefinition leads to serious inconsistencies and misunderstanding because the definition provided is unclear. Even if one were to presume that the redefinition of the term includes all physical properties that are not direct measurements of composition. The specification creates greater confusion by stating that an increase thereof reflects an increase in “the concentrations of ethane, propane, and butane” in the LNG (see pages 3-4). However, this seems to be inconsistent with earlier in the specification where the disclosure states that the freezable component may include benzene, carbon dioxide, and water as components that may freeze (see spec. page 1, line 19-20) and it is entirely unclear how to interpret the recited term, if the physical property definition is only considered to include properties indicative of increases in concentrations of ethane, propane, and butane and not include properties indicative of concentrations of benzene, carbon dioxide, and water. Therefore the recitation is unclear since there is no way to discern what properties are and are not included by the definition and it is even unclear what properties are sufficiently “indirect” to be included and yet still be indicative of some vague notion of risk associated with an inclusion of unclear freezable component. For examination, “physical property” is interpreted to as any physical property is interpreted as a characteristic of matter that is not a direct measurement of composition. The recitation, “if there is the risk of freezing” is indefinite for improperly reintroducing anew “freezing” and it is unclear if this is the same or other freezing. Further, and most importantly, it is entirely unclear what level of risk qualifies and how high the risk must be to be determined as qualifying. Therefore it is impossible to determine what qualification must occur. The recitation, “if the risk of freezing is confirmed” is indefinite for improperly reintroducing anew “freezing” and it is unclear if this is the same or other freezing. The recitation, “determining, by the computing means, if there is the risk of freezing of the at least one component of the cryogenic liquid stream inside the cryogenic heat exchanger based on the transmitted measurement and a temperature of the first refrigerant stream entering the cryogenic heat exchanger;” is indefinite since it is unclear what operations must be performed relative to the recited temperature and there is no support that the temperature of the first refrigerant is considered by the computing means to determine the risk of the freezing and therefore unclear what steps must be performed to determine the risk of freezing. In regard to claim 2, the recitation, “the risk of freezing” is indefinite for improperly reintroducing anew “freezing” and it is unclear if this is the same or other freezing. The recitation, “indirectly exchange heat” (in the last line of the claim) is indefinite for improperly reintroducing anew “heat” and it is unclear if this is the same or other heat. The recitation, “if the transmitted measurement is within a freezing range calculated by the computing means at the temperature of the first refrigerant stream” is indefinite as it is unclear what is at the temperature of the first refrigerant - the computing means or something else. Further, the transmitted measurement is of the vaporized partial stream of the cryogenic liquid stream and not of the first refrigerant and it is entirely unclear what relationship must exist with the temperature of the first refrigerant stream. There is no way to make any sense of this recitation. Further, the recitation is indefinite since the disclosed measurements are not a temperature (spec. page 15) and it is unclear what exactly would make the measurement within a “freezing range”. In regard to claim 4, the recitation, “indirectly exchange heat” (see both recitations) is indefinite for improperly reintroducing anew “heat” and it is unclear if this is the same or other heat. In regard to claim 5, the recitation, “indirectly exchange heat” is indefinite for improperly reintroducing anew “heat” and it is unclear if this is the same or other heat. In regard to claim 7, the recitation, “the risk of freezing” is indefinite for improperly reintroducing anew “freezing” and it is unclear if this is the same or other freezing. CLAIM INTERPRETATION The following is a quotation of 35 U.S.C. 112(f): (f) Element in Claim for a Combination. – An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof. The following is a quotation of pre-AIA 35 U.S.C. 112, sixth paragraph: An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof. The claims in this application are given their broadest reasonable interpretation using the plain meaning of the claim language in light of the specification as it would be understood by one of ordinary skill in the art. The broadest reasonable interpretation of a claim element (also commonly referred to as a claim limitation) is limited by the description in the specification when 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is invoked. As explained in MPEP § 2181, subsection I, claim limitations that meet the following three-prong test will be interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph: (A) the claim limitation uses the term “means” or “step” or a term used as a substitute for “means” that is a generic placeholder (also called a nonce term or a non-structural term having no specific structural meaning) for performing the claimed function; (B) the term “means” or “step” or the generic placeholder is modified by functional language, typically, but not always linked by the transition word “for” (e.g., “means for”) or another linking word or phrase, such as “configured to” or “so that”; and (C) the term “means” or “step” or the generic placeholder is not modified by sufficient structure, material, or acts for performing the claimed function. Use of the word “means” (or “step”) in a claim with functional language creates a rebuttable presumption that the claim limitation is to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites sufficient structure, material, or acts to entirely perform the recited function. Absence of the word “means” (or “step”) in a claim creates a rebuttable presumption that the claim limitation is not to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is not interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites function without reciting sufficient structure, material or acts to entirely perform the recited function. Claim limitations in this application that use the word “means” (or “step”) are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action. Conversely, claim limitations in this application that do not use the word “means” (or “step”) are not being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action. Claim limitation “expansion means” invokes 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph and is interpreted as a turbine (spec. page 14, line 12) or its equivalents including at least expansion valves. Claim limitation “computing means” invokes 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph and is interpreted as a computer (spec. page 14, line 12). Claim Rejections - 35 USC § 103 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 set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied 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. Claim(s) 1-5, 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kaminsky (US 2021/0063083) in view of Schreiner (WO 2018/185007). See the 112 rejections and note that the prior art teaches the claimed features as far as can be interpreted. Further note the interpretation of the claim language as outlined in the rejection below. In regard to claim(s) 1, 3, Kaminsky teaches a method for avoiding freezing of at least one component (para. 31) of a cryogenic liquid stream (natural gas being liquefied) inside a cryogenic heat exchanger (see 130, 231, HX2, HX3, hereafter 130, 231 for simplicity) indirectly exchanging heat with a first refrigerant stream (of 240) circulating inside a closed refrigeration cycle (240) and entering the cryogenic heat exchanger (130, 231) after expansion through at least one expansion means (251) of the closed refrigeration cycle (240) to indirectly exchange the heat with the cryogenic liquid stream (para. 32-33), the cryogenic liquid stream (liquid natural gas) being a different composition from the first refrigerant stream (para. 30, 32), and comprising the steps of: measuring at least one physical property (para. 40 see at least pressure) of the portion of the cryogenic liquid stream (liquid natural gas), the at least one physical property measured being an indirect indicator (see that the pressure is an indirect indicator of whether CO2 may freeze, para. 40) of the risk of the freezing of the at least one component (para. 39-40 carbon dioxide) of the cryogenic liquid stream (natural gas) inside the cryogenic heat exchanger (130, 231); - transmitting a measurement of the at least one physical property (interpreted as a property of matter) (the measurement of composition is sent to the “control system” for monitoring, para. 39-40) to a computing means (“control system”, para. 39); - determining by the computing means (control system) if there is the risk of the freezing of the at least one component of the cryogenic liquid stream (liquid natural gas) inside the cryogenic heat exchanger (130, 231) based on the transmitted measurement (para. 39-43; “predicts the onset of CO2 precipitation”) and a temperature (para. 40-44 “temperature T12” controlled to prevent freezing) of the first refrigerant stream (of 240) entering the cryogenic heat exchanger (130, 231); - if the risk of the freezing is confirmed (para. 39-43), increasing a temperature (para. 43 maintaining temperature above CO2 freezing; para. 39 maintaining the temperature of the natural gas so as to prevent freez-out and blockages) of the first refrigerant stream (para. 39-43, by controlling the speed of the compressor) entering the cryogenic heat exchanger (130, 231). Kaminsky does not explicitly teach withdrawing and vaporizing a partial stream of the cryogenic liquid stream prior to the heat exchanger (130, 231) to make the measurement above and Kaminsky does not appear to explicitly teach measuring thermal conductivity. However, it is routine to withdraw a sample of a fluid to determine its properties. For example, Schreiner teaches it is well known to determine a composition of natural gas (page 10) with a sensor (100) from a measure of thermal conductivity (page 10) of at least a portion of natural gas (page 1 “natural gas”) and that this permits more affordable determination of the composition (page 1-2 “selective measurement is very difficult…often correlative techniques are applied”, page 3 - so as to permit determination of the composition of the natural gas and the calorific value of the natural gas). Therefore it would have been obvious to those of ordinary skill in the art at the time the invention was made to modify Kaminsky with withdrawal and vaporization of a portion of the liquefying natural gas to permit measurement of a correlative parameter, including thermal conductivity, as taught by Schreiner, for the purpose of making it easer to determine a calorific value of the natural gas and to make it easier to determine the composition the natural gas and to permit more accurate operational decisions concerning unsafe levels of carbon dioxide or other freezable constituents. In regard to claim 2, Kaminsky, as modified, teaches that the risk of the freezing of the at least one component (CO2 freezeout, para. 39) of the cryogenic liquid (liquid natural gas) is confirmed if the transmitted measurement is within a determined value (para. 39-43; also see Schreiner’s parameters correlate with the presence of freezable components in natural gas) calculated by the computing means (control system as modified). In rehearsed regard to claim 3, see that Schreiner teaches the measurement of thermal conductivity (page 3, para. 5) and additionally of a wobbe index (page 5, para. 6). In regard to claim 4-5, Kaminsky teaches that the temperature of the first refrigerant stream (from 251) entering the cryogenic heat exchanger (130, 231) to indirectly exchange the heat with the cryogenic liquid stream (liquid natural gas) is increased (see temperature is increased to maintain temperature above CO2 freezing, para. 43) by decreasing a mass flow of the first refrigerant stream circulating within the closed loop (240) by decreasing a speed (compressor speed, para. 43) of at least one refrigerant compressor (C2, para. 43). In regard to claim 7, Kaminsky teaches a pressure drop (para. 41, “pressure drop”) across the cryogenic heat exchanger (130, 231) on a side of the cryogenic liquid stream (liquid natural gas) is measured (para. 41), transmitted to the computing means (control system) and used for determining the risk of the freezing (para. 41 “in addition…to ensure detection and reduction of solids build-up in the heat exchangers”) of the at least one component (CO2) of the cryogenic liquid stream (liquid natural gas) inside the cryogenic heat exchanger (130, 231). Claim(s) 1-5, 7, 13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kaminsky (US 2021/0063083) in view of Schreiner (WO 2018/185007) and Hutchinson (US 2019/0024847). See the 112 rejections and note that the prior art teaches the claimed features as far as can be interpreted. Further note the interpretation of the claim language as outlined in the rejection below. In regard to claims 1-5, 7, Kaminsky does not appear to explicitly teach that the feed stream is a liquid stream that is subcooled. However, Hutchinson explicitly teaches that it is routine for a feed stream to a refrigeration system be a liquid stream that is subcooled with refrigeration cycles (see Fig. 4-5). Therefore it would have been obvious to those of ordinary skill in the art at the time the invention was made to employ the method of Kaminsky in subcooling situations to provide the ability to avoid freezing when subcooling and expand the applicability of Kaminsky. In consequence, a risk of freezing a component in a cryogenic liquid stream being subcooled would be reduced. In regard to claim 13, Kaminsky, as modified, appears to teach most of the claim limitations as best understood, but does not appear to explicitly state that the method is used onboard a sea-going LNG carrier. However, Hutchinson teaches that such LNG carriers are routine and ordinary and that subcooling of LNG is routine and ordinary with refrigeration cycles (see Fig. 4-5). Therefore it would have been obvious to those of ordinary skill in the art at the time the invention was made to provide Kaminsky as modified upon an LNG ship for the purpose of providing the ability to protect the heat exchangers of Hutchinson from CO2 freezing during its cooling operations so as to extend the benefits of Kaminsky, as modified, to sea going vessels thereby providing the improved freeze protection to the heat exchangers of LNG carriers as well. Response to Arguments Applicant's arguments filed 3/17/2026 have been fully considered but they are not persuasive. Applicant's arguments (page 6) are an allegation that the definition employed by the specification for the term “physical property” is definite merely because the specification lists properties in claim 3. In response, the allegation is unpersuasive as the specification has not clearly redefined the term and the “examples” referenced do not provide a clear redefinition. Applicant's arguments (page 7) are an allegation that the amendment is now drawn to a liquid stream and therefore Kaminsky is not relevant. In response, the allegation is unpersuasive since Kaminsky is explicitly concerned with avoiding freezing of at least one component of a cryogenic liquid stream inside a cryogenic heat exchanger as claimed. Applicant's arguments (page 7) are an allegation that none of the teachings of Kaminsky could be applied to a subcooling operation, since such would “render the method of Kaminsky unsuitable for its intended purpose”. In response, the allegation is unpersuasive as applying the teachings of Kaminsky to other cooling situations does not amount to eliminating the benefits and purpose of Kaminsky but is merely an extension and natural application and continuation of the methods of Kaminsky. The allegation is unpersuasive for being without any support or merit. Conclusion Applicant's amendment necessitated any of 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. The prior art made of record on the 892 form and not relied upon is considered pertinent to applicant's disclosure. Any inquiry concerning this communication or earlier communications from the examiner should be directed to JOHN F PETTITT whose telephone number is (571)272-0771. The examiner can normally be reached on M-F, 9-5p. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR): http://www.uspto.gov/interviewpractice. The examiner’s supervisor, Frantz Jules can be reached on 571-272-6681. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see http://pair-direct.uspto.gov. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /JOHN F PETTITT, III/Primary Examiner, Art Unit 3763
Read full office action

Prosecution Timeline

Nov 22, 2023
Application Filed
Dec 17, 2025
Non-Final Rejection mailed — §103, §112
Mar 17, 2026
Response Filed
Oct 01, 2026
Final Rejection mailed — §103, §112 (current)

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Expected OA Rounds
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Grant Probability
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