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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on March 18th, 2026 has been entered.
Claim Objections
Claims 1 and 8-9 objected to because of the following informalities:
Claim 1, line 26: “sequentially passes therethrough” should read “sequentially passes through the first turbo expander and the second turbo expander”
Claim 8 is also objected to by virtue of its dependency on claim 1.
Claim 9 is also objected to by virtue of its dependency on claim 8.
Appropriate correction is required.
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 1 and 8-9 are rejected under 35 U.S.C. 103 as being unpatentable over Shim et al. (KR 20210126800), hereinafter Shim in view of Ishimaru et al. (US 20140053598), hereinafter Ishimaru, Higo et al. (JPH 02171579), hereinafter Higo, and Turney et al. (US Patent No. 12,584,686), hereinafter Turney.
Regarding claim 1, Shim discloses a hydrogen liquefaction system without pre-cooling based on a refrigeration cycle (Fig. 1, hydrogen liquefaction and natural gas suppression system 1; Further, the hydrogen liquefaction and natural gas suppression system 1 of Fig. 1 of Shim does not include any separate pre-cooling refrigeration cycle) comprising:
a first pipe set in which gaseous hydrogen is liquefied into liquid hydrogen (See annotated Fig. 1 of Shim below, first pipe set A; Pg. 9, paragraph 70, The hydrogen liquefaction unit 40 cools and liquefies gaseous hydrogen supplied from the outside through heat exchange with a refrigerant circulating continuously in the refrigerant circulation unit 20, and then fills the storage tank 10);
a second pipe set and a third pipe set forming a closed-loop refrigeration cycle through which refrigerant flows to exchange heat with the gaseous hydrogen flowing through the first pipe set (Annotated Fig. 1 of Shim depicts second pipe set B and third pipe set C to form a refrigeration cycle of a closed loop; Pg. 8, paragraph 50, The refrigerant circulation unit 20 expands and depressurizes the high-temperature and high-pressure refrigerant to convert it into a low-temperature and low-pressure refrigerant, and continuously circulates it to cool gaseous hydrogen and natural gas);
a first heat exchanger and a third heat exchanger sequentially arranged in a direction in which the gaseous hydrogen flows in the first pipe set (annotated Fig. 1 of Shim depicts the first heat exchanger unit 25 to be in heat exchange with the first pipe set A, the second pipe set B and the third pipe set C and the third heat exchanger unit 25 to be in heat exchange with the first pipe set A and the third pipe set C; Pg. 8, paragraph 53, And the refrigerant circulation unit 20 flows the high-temperature high-pressure refrigerant and the low-temperature low-pressure refrigerant circulating along the first refrigerant circulation line 21 in opposite directions to exchange thermal energy with each other, so that the hydrogen supply line of the hydrogen liquefaction unit 40 At least one heat exchange unit 25 for cooling gaseous hydrogen supplied along (41) is provided),
a first turbo expander provided in the second pipe set and located downstream of the first heat exchanger (See annotated Fig. 1 of Shim, expansion unit 26 is disposed on second pipe set B downstream of heat exchange unit 25), and
a refrigerant compressor provided on one side of the second pipe set and one side of the third pipe set (See annotated Fig. 1 of Shim, refrigerant compression unit 22 is provided on one side of the second pipe sent B and one side of the third pipe set C).
Shim does not explicitly disclose a second heat exchanger sequentially arranged with the first heat exchanger and the third heat exchanger,
wherein the second heat exchanger cools the gaseous hydrogen that has passed through the first heat exchanger by heat exchange with the refrigerant that has passed through the first turbo expander.
However, Shim suggests that a plurality of heat exchange units can be used as the heat exchange capacity increases with the addition of heat exchangers (Pg. 8, paragraphs 55-58, Here, the heat exchange unit 25 may be divided into a plurality of heat exchange zones, and the heat exchange units 25 of each divided zone may be connected to each other to circulate the refrigerant. In addition, when helium is used as a refrigerant in the heat exchange unit 25, several devices may be arranged side by side along the first refrigerant circulation line 21 to facilitate heat exchange or cooling of the refrigerant. For example, at least one or more heat exchange units 25 may be arranged in series or parallel combination and operated together to increase heat exchange capacity and efficiency. That is, the heat exchange between the refrigerants is duplicated through the plurality of heat exchange units 25, thereby overcoming limitations in size (capacity) and performance, and re-liquefying the natural gas in the storage tank 10 more efficiently).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the hydrogen liquefaction system without pre-cooling of Shim of claim 1 to include a second heat exchanger sequentially arranged with the first heat exchanger and the third heat exchanger and, the second heat exchanger cooling the gaseous hydrogen cooled while passing through the first heat exchanger, specifically positioned between the two heat exchanger units 25 depicted in Fig. 1 of Shim. One of ordinary skill in the art would have been motivated to make this modification because the heat exchange between the refrigerants is duplicated through the plurality of heat exchange units 25, thereby overcoming limitations in size (capacity) and performance, and re-liquefying the natural gas in the storage tank 10 more efficiently (Shim, Pg. 8, paragraphs 58). Further, the modification described herein results wherein the second heat exchanger cools the gaseous hydrogen that has passed through the first heat exchanger by heat exchange with the refrigerant that has passed through the first turbo expander (Pg. 8, paragraph 53, And the refrigerant circulation unit 20 flows the high-temperature high-pressure refrigerant and the low-temperature low-pressure refrigerant circulating along the first refrigerant circulation line 21 in opposite directions to exchange thermal energy with each other, so that the hydrogen supply line of the hydrogen liquefaction unit 40 At least one heat exchange unit 25 for cooling gaseous hydrogen supplied along (41) is provided). Moreover, regarding the second heat exchanger, “the courts have held that mere duplication of parts has no patentable significance unless a new and unexpected result is produced. In re Harza, 274 F.2d 669, 124 USPQ 378 (CCPA 1960): (Claims at issue were directed to a water-tight masonry structure wherein a water seal of flexible material fills the joints which form between adjacent pours of concrete. The claimed water seal has a "web" which lies in the joint, and a plurality of "ribs" projecting outwardly from each side of the web into one of the adjacent concrete slabs. The prior art disclosed a flexible water stop for preventing passage of water between masses of concrete in the shape of a plus sign (+). Although the reference did not disclose a plurality of ribs, the court held that mere duplication of parts has no patentable significance unless a new and unexpected result is produced.)” MPEP § 2144.04-VI-B.
Shim as modified further discloses wherein the gaseous hydrogen is cooled step by step by the first heat exchanger, the second heat exchanger, and the third heat exchanger and liquefied into the liquid hydrogen (Shim, Pg. 9, paragraph 70, The hydrogen liquefaction unit 40 cools and liquefies gaseous hydrogen supplied from the outside through heat exchange with a refrigerant circulating continuously in the refrigerant circulation unit 20, and then fills the storage tank 10). Further, the cooling of the gaseous hydrogen in the second heat exchanger is a result of the modification relied upon in the rejection of claim 1.
However, Shim as modified does not disclose the gaseous hydrogen supplied through a gaseous hydrogen buffer tank.
Ishimaru teaches the gaseous hydrogen supplied through a gaseous hydrogen buffer tank (Fig. 1, raw material tank 1; Pg. 3, paragraph 35, The raw material tank 1 is a source of supply of the raw material gas, and stores the hydrogen gas at a normal temperature and pressure).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the hydrogen liquefaction system without pre-cooling of Shim as modified wherein the gaseous hydrogen supplied through a gaseous hydrogen buffer tank as taught by Ishimaru. One of ordinary skill in the art would have been motivated to make this modification to provide onsite storage of the feed gas to allow for improved rates of production.
Further, Shim as modified does not disclose the first turbo expander to be located between the first heat exchanger and the second heat exchanger, and
a second turbo expander provided on another side of the second pipe set and on another side of the third pipe set, and located between the second heat exchanger and the third heat exchanger; and
wherein the first turbo expander and the second turbo expander are arranged in series in the closed-loop refrigeration cycle such that the refrigerant sequentially passes therethrough and temperature and pressure levels of the refrigerant are sequentially reduced.
Higo teaches a turbo expander to be located between two heat exchangers (Fig. 1 of Higo depicts second expansion turbine 37 to be disposed between heat exchanger 9 and heat exchanger 12, heat exchanger 9 and heat exchanger 12 corresponding the first and second heat exchangers of the claimed invention, respectively, as both heat exchanger 9 and heat exchanger 12 are in thermal communication with all three pipe sets of Higo),
a turbo expander provided on another side of the second pipe set and on another side of the third pipe set, and located between the second heat exchanger and the third heat exchanger (Fig. 1 of Higo depicts third expansion turbine 38 to be provided on another side of the second pipe set B’ and on another side of third pipe set C’, and located between heat exchanger 12 and heat exchanger 17, heat exchanger 12 and heat exchanger 17 corresponding the second and third heat exchangers of the claimed invention, respectively, as heat exchanger 12 is in thermal communication with all three pipe sets of Higo and heat exchanger 17 is in thermal communication with the third pipe set and the first pipe set); and
wherein the first turbo expander and the second turbo expander are arranged in series in the closed-loop refrigeration cycle such that the refrigerant sequentially passes therethrough and temperature and pressure levels of the refrigerant are sequentially reduced (Fig. 1 of Higo depicts second expansion turbine 37 and the third expansion turbine 38 are arranged in series in the closed-loop refrigeration cycle such that the refrigerant sequentially passes therethrough and temperature and pressure levels of the refrigerant are sequentially reduced; Further, the second expansion turbine 37 and the third expansion turbine 38 of Higo have the same structure as the claimed first and second turbo expanders and are capable of functioning in the manner claimed).
Shim as modified fails to teach disclose the first turbo expander to be located between the first heat exchanger and the second heat exchanger, a second turbo expander provided on another side of the second pipe set and on another side of the third pipe set, and located between the second heat exchanger and the third heat exchanger; and wherein the first turbo expander and the second turbo expander are arranged in series in the closed-loop refrigeration cycle such that the refrigerant sequentially passes therethrough and temperature and pressure levels of the refrigerant are sequentially reduced, however Higo teaches that it is a known method in the art of hydrogen liquefaction to include the first turbo expander to be located between the first heat exchanger and the second heat exchanger, a second turbo expander provided on another side of the second pipe set and on another side of the third pipe set, and located between the second heat exchanger and the third heat exchanger; and wherein the first turbo expander and the second turbo expander are arranged in series in the closed-loop refrigeration cycle such that the refrigerant sequentially passes therethrough and temperature and pressure levels of the refrigerant are sequentially reduced. This is strong evidence that modifying Shim as modified as claimed would produce predictable results (i.e. sufficient depressurization of the refrigerant to ensure adequate cooling compacity within the system to improve overall system efficiencies). Accordingly, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Shim as modified by Higo and arrive at the claimed invention since all claimed elements were known in the art and one having ordinary skill in the art could have combined the elements as claimed by known methods with no changes in their respective functions and the combination would have yielded the predictable result of sufficient depressurization of the refrigerant to ensure adequate cooling compacity within the system to improve overall system efficiencies. Further, the modification of references as described herein to include the second turbo expander located between the second heat exchanger and the third heat exchanger result in wherein the third heat exchanger cools the gaseous hydrogen that has passed through the second heat exchanger by heat exchange with the refrigerant that has passed through the second turbo expander (Shim, Pg. 8, paragraph 53, And the refrigerant circulation unit 20 flows the high-temperature high-pressure refrigerant and the low-temperature low-pressure refrigerant circulating along the first refrigerant circulation line 21 in opposite directions to exchange thermal energy with each other, so that the hydrogen supply line of the hydrogen liquefaction unit 40 At least one heat exchange unit 25 for cooling gaseous hydrogen supplied along (41) is provided).
Moreover, Shim as modified does not disclose wherein the first heat exchanger, the second heat exchanger, the third heat exchanger, the first turbo expander, and the second turbo expander are disposed within a cold box.
Turney teaches heat exchangers and expanders of a hydrogen liquefaction system to be disposed within a cold box (Fig. 3, cold-box 1, precooling system 20, liquefying system 30; Col. 10, lines 22-33, HLU 10 preferably comprises a precooling system 20, a liquefying system 30, a primary refrigeration system 70, a secondary refrigeration system (60, 62,64), and a thermal insulator such as a cold-box 10, which provides thermal insulation for certain equipment within HLU 10 that will be exposed to temperatures below freezing. Precooling system 20 and liquefying system 30 preferably include heat exchangers configured to operate at cryogenic temperatures and exchange heat between two or more stream via indirect heat exchange. The types of heat exchangers used in certain embodiments can be chosen appropriately by one of ordinary skill in the art).
Therefore, it would have been obvious before the effective filing date of the claimed invention to modify the system of Shim as modified wherein the first heat exchanger, the second heat exchanger, the third heat exchanger, the first turbo expander, and the second turbo expander are disposed within a cold box as taught by Turney. One of ordinary skill in the art would have been motivated to make this modification to provide thermal insulation for certain equipment within hydrogen liquefaction unit that will be exposed to temperatures below freezing to improve overall system efficiencies (Turney, Col. 10, lines 25-27).
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Annotated Fig. 1 of Shim
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Annotated Fig. 1 of Higo
Regarding claim 8, Shim as modified discloses an integrated lossless liquid hydrogen storage system (Shim, Fig. 1, hydrogen liquefaction and natural gas suppression system 1; Abstract, a heat exchange tube provided so that the low-temperature and low-pressure refrigerant converted from the refrigerant circulation unit circulates inside the storage tank, and configured to cool and liquefy the BOG evaporated and vaporized from the liquid hydrogen in the storage tank, by the endothermic action of the refrigerant circulating inside the heat exchange tube), comprising:
a liquid hydrogen storage tank for storing liquefied liquid hydrogen supplied from the first pipe set of the hydrogen liquefaction system according to Claim 1 (Shim, Fig. 1, storage tank 10; Pg. 9, paragraph 70, The hydrogen liquefaction unit 40 cools and liquefies gaseous hydrogen supplied from the outside through heat exchange with a refrigerant circulating continuously in the refrigerant circulation unit 20, and then fills the storage tank 10; see the combination of references used in the rejection of claim 1 above), and
wherein an extended part of the second pipe set of the hydrogen liquefaction system branches and extends to the liquid hydrogen storage tank, and the refrigerant flowing through the extended part of the second pipe set exchanges heat with the liquid hydrogen stored in the liquid hydrogen storage tank to absorb evaporation heat of the liquid hydrogen (Shim, Fig. 1, heat exchanger tube 30, refrigerant inlet line 31; Pg. 9, paragraph 63-65, The heat exchange tube 30 serves to cool and liquefy the naturally vaporized gas evaporated and vaporized from the liquid hydrogen in the storage tank 10 by the endothermic action of the refrigerant converted and separated in the refrigerant circulation unit 20. To this end, the refrigerant in the low-temperature and low-pressure state of the refrigerant circulation unit 20 is circulated to the inside of the storage tank 10. That is, the refrigerant circulating in the heat exchange tube 30 in the refrigerant circulation unit 20 absorbs the heat of the naturally vaporized gas generated in the storage tank 10 to cool and liquefy it).
Regarding claim 9, Shim as modified discloses the integrated lossless liquid hydrogen storage system according to Claim 8 (see the combination of references used in the rejection of claim 8 above),
wherein, after the refrigerant flowing through the extended part of the second pipe set exchanges heat with the liquid hydrogen stored in the liquid hydrogen storage tank to absorb the evaporation heat of the liquid hydrogen, the refrigerant is retrieved to the hydrogen liquefaction system (Shim, Fig. 1, refrigerant outlet line 32; Pg. 9, paragraph 66, Here, the heat exchange tube 30 is connected to communicate with the first refrigerant circulation line 21 of the refrigerant circulation unit 20 by the refrigerant inlet line 31 and the refrigerant outlet line 32).
Response to Arguments
Applicant's arguments filed March 18th, 2026 have been fully considered but they are not persuasive.
Applicant argues on Pg. 7 (as numbered by the Applicant) of the Remarks, “The Office cites the expansion turbine 37 of Higo as teaching a first turbine, and the expansion turbine 38 of Higo as teaching a second turbine. Office Action, p. 7. However, the expansion turbine 37 cannot teach the claimed first turbine, at least because it is not located between a first heat exchanger and a second heat exchanger, as required by claim 1. Rather, as shown in FIG. 1 of Higo, reproduced at right, Higo teaches consecutive heat exchangers 9, 10, 12, 13, and 17. The expansion turbine 37 is located between non-consecutive heat exchangers 9, 12, and the expansion turbine 38 is located between non-consecutive heat exchangers 12, 17. This is not equivalent to an arrangement with a first turbo expander located between a consecutive first and second heat exchangers, and a second turbo expander located between a consecutive second and third heat exchanger.”
However, this argument is not persuasive as the Examiner does not rely on the expansion turbine 37 of Higo to teach the first turbo expander as alleged by the Applicant. The first turbo expander is disclosed by the base ref Shim as expansion unit 26 of Fig. 1 of Shim. The expansion turbines 37 and 38 of Higo are simply relied upon to show it is known in the art of hydrogen liquefaction to include multiple expansion turbines in a series arrangement in between sequential heat exchangers of the system to yield the predictable results of sufficient depressurization of the refrigerant to ensure adequate cooling compacity within the system to improve overall system efficiencies (See Fig. 1 of Higo). Further, in response to applicant's argument that the references fail to show certain features of the invention, it is noted that the features upon which applicant relies (i.e., a consecutive first and second heat exchanger) are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993). More specifically, the claims only require the first, second, and third heat exchangers to be “sequentially arranged in a direction in which the gaseous hydrogen flows in the first pipe set” the term “consecutive” is not used anywhere in the claims. Moreover, the sequentially arranged heat exchangers as claimed do not preclude other components from being disposed in between them, just that they are arranged sequentially in a direction in which the gaseous hydrogen flows in the first pipe set. See the rejection of claim 1 above.
Applicant argues on Pg. 7-8 (as numbered by the Applicant) of the Remarks, “Further, the claimed arrangement of a first, second, and third heat exchanger "sequentially arranged in a direction in which the gaseous hydrogen flows in the first pipe set", a first turbo expander provided in the second pipe set and "located between the first heat exchanger and the second heat exchanger", and a second turbo "located between the second heat exchanger and the third heat exchanger" is not an obvious arrangement in light of Shim, Ishimaru, and Higo. The Office alleges that it would have been obvious to one of ordinary skill in the art to modify shim using Higo to arrive at the claimed inventions since "all claimed elements were known in the art, and one having ordinary skill in the art could have combined the elements as claimed by known methods." Office Action, p. 8. The Examiner has provided no evidence that the proposed modification would produce predictable results. Indeed, there is no rationale as to why one of ordinary skill in the art would, inter alia, reduce a number of heat exchangers to achieve a desired cooling of hydrogen. The Office has further failed to explain why it would be obvious to one of ordinary skill in the art to arrange the first, second, and third heat exchangers, and the first and second turbo expanders as claimed. The particular arrangement of elements recited in the claims facilitates a step-by-step cooling of hydrogen, without requiring a liquid nitrogen pre-cooling. Specification, para. [0017], [0044]-[0047], Table 1. The claimed sequence of elements facilitating the specific cooling profile described in the Specification is a unique solution for high-efficiency liquefaction and cannot be derived through a predictable combination of the cited references without the benefit of hindsight.”
However, this argument is not persuasive as the Examiner does not propose removing any heat exchangers as alleged by the Applicant, but rather proposed adding a heat exchanger between the two heat exchanger units 25 of Shim which is suggested as a possibility by the disclosure of Shim (Shim, Pg. 8, paragraphs 55-58, Here, the heat exchange unit 25 may be divided into a plurality of heat exchange zones, and the heat exchange units 25 of each divided zone may be connected to each other to circulate the refrigerant. In addition, when helium is used as a refrigerant in the heat exchange unit 25, several devices may be arranged side by side along the first refrigerant circulation line 21 to facilitate heat exchange or cooling of the refrigerant. For example, at least one or more heat exchange units 25 may be arranged in series or parallel combination and operated together to increase heat exchange capacity and efficiency. That is, the heat exchange between the refrigerants is duplicated through the plurality of heat exchange units 25, thereby overcoming limitations in size (capacity) and performance, and re-liquefying the natural gas in the storage tank 10 more efficiently). Further, the base ref Shim already discloses step-by-step cooling of hydrogen without requiring a liquid nitrogen pre-cooling (See Fig. 1 of Shim which does not include any separate pre-cooling refrigeration cycle). Moreover, in response to applicant's argument that “The claimed sequence of elements facilitating the specific cooling profile described in the Specification is a unique solution for high-efficiency liquefaction and cannot be derived through a predictable combination of the cited references without the benefit of hindsight”, the fact that the inventor has recognized another advantage which would flow naturally from following the suggestion of the prior art cannot be the basis for patentability when the differences would otherwise be obvious. See Ex parte Obiaya, 227 USPQ 58, 60 (Bd. Pat. App. & Inter. 1985). Additionally, in response to applicant's argument that the examiner's conclusion of obviousness is based upon improper hindsight reasoning, it must be recognized that any judgment on obviousness is in a sense necessarily a reconstruction based upon hindsight reasoning. But so long as it takes into account only knowledge which was within the level of ordinary skill at the time the claimed invention was made, and does not include knowledge gleaned only from the applicant's disclosure, such a reconstruction is proper. See In re McLaughlin, 443 F.2d 1392, 170 USPQ 209 (CCPA 1971).
The rejection of independent claim 1 is maintained. The rejections of dependent claims 8-9 are also maintained for at least the reasons described herein.
Conclusion
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/DEVON MOORE/Examiner, Art Unit 3763 April 08th, 2026