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 .
This action in response to remarks and amendments filed 3/20/2026.
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 2-4, 6 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 2 recites “a first refrigerant first compression part provided upstream of the cryogenic heat exchanger and configured to compress the first refrigerant to a high pressure”; however, claim 1 has already required the presence of “a first refrigerant first compression part” and as such the recitation in claim 2 is unclear how it relates to the already present component. For the purpose of examination, this limitation is interpreted such that claim 2 only further limits the claim in regard to the location of the compression part as well as that the pressure provided is a high pressure.
Claim 3 recites “a first refrigerant first compression part provided upstream of the cryogenic heat exchanger and configured to compress the first refrigerant to a high pressure”; however, claim 1 has already required the presence of “a first refrigerant first compression part” and as such the recitation in claim 3 is unclear how it relates to the already present component. For the purpose of examination, this limitation is interpreted such that claim 3 only further limits the claim in regard to the location of the compression part as well as that the pressure provided is a high pressure.
Claims 4 and 6 are rejected as being dependent upon a rejected claim.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim(s) 1-8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Seitter et al. (US PG Pub 20160061517), hereinafter referred to as Seitter and Wyllie et al. (US PG Pub 20140245780), hereinafter referred to as Wylie.
With respect to claim 1, Seitter (Figure 1) teaches a natural gas liquefaction apparatus comprising: a cryogenic heat exchanger through which natural gas passes through and is liquefied into liquefied natural gas through heat exchange with a first refrigerant and a second refrigerant (first refrigeration system 12 and second refrigeration system 14 each having a refrigerant, which can a single heat exchanger, paragraph 39 with multiple zones, which produces LNG, paragraph 40);
a first refrigerant cycle through which the first refrigerant circulates, which has some paths passing through the cryogenic heat exchanger to perform heat exchange (first refrigerant cycle is the one of first refrigeration system 12 which has flow paths through zones 20, 26, and 32, paragraph 34-35),
and which has a path of the first refrigerant divided into a plurality of paths after performing heat exchange at the cryogenic heat exchanger (the refrigerant from the first cycle splits into streams via conduits 136, 142 and 152 after passing through portions of the heat exchanger, paragraph 52, 59, 66), wherein each of the plurality of paths is configured to carry a respective flow of the first refrigerant (all three split paths carry portions of the refrigerant),
and performs expansion of the first refrigerant through the paths using at least two expanders (the streams from 136, 152 and 142 are expanded in 60, 64 and 70 respectively which can be hydraulic turbines, paragraphs 52, 59 and 66),
and a second refrigerant cycle through which the second refrigerant circulates and which has some paths passing through the cryogenic heat exchanger (second refrigeration system 14 has multiple pathways in the heat exchanger, paragraphs 86-87, 90).
Seitter does not teach the first refrigerant cycle is configured to perform pre-compression of at least two divided flows of the first refrigerant through the plurality of paths by at least two respective first refrigerant turbo expanders, and to mix the at least two divided flows of the first refrigerant pre-compressed by the at least two respective first refrigerant turbo expanders and transfer the mixed flows to a first refrigerant first compression part.
Wyllie (Figure 3) teaches a system substantially similar to that of the Seitter where after individual streams are expanded, they are combined and compressed together (paragraphs 66-68), but teaches an alternative embodiment (Figure 5) where a single stream of refrigerant (CS) that is fed into the heat exchanger is split into three separate streams (HS, IS, LS) and after expansion (HS in HE, IS in IE, LS in LE) and being used for cooling each stream is fed to a respective compressor in parallel (HC for expanded HS, IC for expanded IS, LC for expanded LS) which are configured as turboexpanders before the streams are all combined during further compression (Paragraphs 86-89).
Therefore it would have been obvious to a person having ordinary skill in the art at the time the invention as filed to have in have provided upstream of the compressor system (48) to have provided a compressor on each of the flow lines (128, 146, and 156) of Seitter which is coupled to the respective expander (60, 64, 70) for each flow path in the configuration of a turboexpander (which is what would be required for them to be coupled) based on the teaching of Wyllie since it has been shown that combining prior art elements to yield predictable results is obvious whereby it is desirable as taught by Wyllie to reduce the power demands of a refrigeration cycle (paragraph 7) and it would be common knowledge in the art that providing compression in part by using the expansion energy in the configuration as shown by Wyllie would allow for a reduction in the remaining compression requirement which would reduce the overall power requirement for the refrigeration cycle. This configuration would result in an expander coupled to a compressor, for each of the three divided flow paths, which compression would come after the divided flow paths are used for providing cooling and such compression can be considered pre-compression as it is followed by whatever additional compression is required in the compressor system. This would meet the limitation as claimed as the divided flow on 128 would be “pre-compressed” in a compressor and mixed after compressor stage 54 or further together in 50 with the “pre-compressed” stream from the compressor on the line 146 before they are passed to compressor stage (50 or 52) which would be a first refrigerant first compression part.
With respect to claim 2, Seitter as modified teaches wherein the first refrigerant cycle comprises: a first refrigerant first compression part provided upstream of the cryogenic heat exchanger and configured to compress the first refrigerant to a high pressure (third compressor stage 50, paragraphs 48-49 which results in the stream being at a pressure that can be considered a high pressure);
and the at least two respective first refrigerant turbo expanders comprise:
a first refrigerant first turbo expander comprising a first refrigerant first expansion part provided downstream of the cryogenic heat exchanger and configured to expand the first flow among the two divided flows of the first refrigerant having passed through the cryogenic heat exchanger (refrigerant from 50 is sent to heat exchanger 20 and after passing through it a portion is separated and expanded in turbine 60 as modified which is part of the turboexpander as modified as the first part of the divided flow), and a first refrigerant pre-compression part configured to pre-compress the first refrigerant which has been expanded by the first refrigerant first expansion part and has passed through the cryogenic heat exchanger again (after expansion, the first part of the refrigerant from 60 passes back into the heat exchanger portion 20 and as modified on line 128 is compressed in a compressor formed as a turboexpander with 60); and
a first refrigerant second expander comprising a first refrigerant second expansion part provided downstream of the cryogenic heat exchanger and configured to expand the second flow among the two divided flows of the first refrigerant having passed through the cryogenic heat exchanger (after more of the refrigerant passes through zone 26, a second portion of the divided flow is expanded in expander 64 which as modified is a turbine), and a first refrigerant second pre-compression part configured to pre-compress the first refrigerant which has been expanded by the first refrigerant second expansion part and has passed through the cryogenic heat exchanger again (after expansion, the second part of the refrigerant from 64 passes back into heat exchanger section 64 and then as modified on line 146 is compressed in a compressor formed as a turboexpander with 64).
With respect to claim 3, Seitter as modified teaches wherein the first refrigerant cycle comprises: a first refrigerant first compression part provided upstream of the cryogenic heat exchanger and configured to compress the first refrigerant to a high pressure (third compressor stage 50, paragraphs 48-49 which results in the stream being at a pressure that can be considered a high pressure);
and the at least two respective first refrigerant turbo expanders comprise:
a first refrigerant first turbo expander comprising a first refrigerant first expansion part provided downstream of the cryogenic heat exchanger and configured to expand the first flow among three divided flows of the first refrigerant having passed through the cryogenic heat exchanger (refrigerant from 50 is sent to heat exchanger 20 and after passing through it a portion is separated and expanded in turbine 60 which is part of the turboexpander as modified as the first part of the divided flow), and a first refrigerant pre-compression part configured to pre-compress the first refrigerant which has been expanded by the first refrigerant first expansion part and has passed through the cryogenic heat exchanger again (after expansion, the first part of the refrigerant from 60 passes back into the heat exchanger portion 20 and as modified on line 128 is compressed in a compressor formed as a turboexpander with 60); and
a first refrigerant second expander comprising a first refrigerant second expansion part provided downstream of the cryogenic heat exchanger and configured to expand the second flow among the two divided flows of the first refrigerant having passed through the cryogenic heat exchanger (after more of the refrigerant passes through zone 26, a second portion of the divided flow is expanded in expander 64 which as modified is a turbine), and a first refrigerant second pre-compression part configured to pre-compress the first refrigerant which has been expanded by the first refrigerant second expansion part and has passed through the cryogenic heat exchanger again (after expansion, the second part of the refrigerant from 64 passes back into heat exchanger section 26 and then as modified on line 146 is compressed in a compressor formed as a turboexpander with 64),
a first refrigerant third expander comprising a first refrigerant third expansion part provided downstream of the cryogenic heat exchanger and configured to expand the third flow among the two divided flows of the first refrigerant having passed through the cryogenic heat exchanger (after more of the refrigerant passes through zone 32, a third portion of the divided flow is expanded in expander 70 which as modified is a turbine), and a first refrigerant third pre-compression part configured to pre-compress the first refrigerant which has been expanded by the first refrigerant third expansion part and has passed through the cryogenic heat exchanger again (after expansion, the third part of the refrigerant from 70 passes back into heat exchanger section 32 and then as modified on line 156 is compressed in a compressor formed as a turboexpander with 70).
With respect to claim 4, Seitter (Figure 1) teaches wherein the first refrigerant compression part is provided in plurality (compressor system 48 comprises multiple compressor stages 54, 52, 50, paragraph 70, which would be a plurality as claimed).
With respect to claim 5, Seitter teaches wherein the second refrigerant cycle comprises:
a second refrigerant compression part provided upstream of the cryogenic heat exchanger and configured to compress the second refrigerant to a high pressure (compressor stage 76, which brings the second refrigerant to a pressure, paragraph 80 which can be considered a high pressure);
and a second refrigerant turbo expander comprising a second refrigerant expansion part provided downstream of the cryogenic heat exchanger and configured to expand the second refrigerant having passed through the cryogenic heat exchanger (refrigerant in conduit 176 has passed through the heat exchanger and is expanded in turbine 90, which can be a hydraulic turbine paragraphs 87-88, a hydraulic turbine would be understood by one having ordinary skill in the art to be a turboexpander, as it is a turbine which expands by isentropic expansion producing work), and a second refrigerant pre-compression part configured to pre-compress the second refrigerant which has been expanded by the second refrigerant expansion part and has passed through the cryogenic heat exchanger again (after passing through 38 from the turbine 90, refrigerant is passed to compressor stage 74, paragraph 79, which as it is upstream of 76 is providing what can be considered pre-compression).
With respect to claim 6, Seitter as modified teaches wherein the first flow of the first refrigerant flowing into the cryogenic heat exchanger from the first refrigerant first expansion part is configured to pass through a warm heat exchange region inside the cryogenic heat exchanger (the first flow of first refrigerant is 136 which passes through the warmest region 20 of the heat exchanger), and the second flow of the first refrigerant flowing into the cryogenic heat exchanger from the first refrigerant second expansion part is configured to sequentially pass through an intermediate heat exchange region and a warm heat exchange region inside the cryogenic heat exchanger (the second flow of refrigerant from 142 is passed to 26 which colder end can be considered an intermediate region of the heat exchanger as it is between ends of the heat exchanger, and is passes through the warm end of 26 which part of 26 can be considered a warm region inside the cryogenic heat exchanger as it is warmer than the cold end of 26 and 32).
With respect to claim 7, Seitter as modified teaches wherein the first refrigerant comprises methane (the first mixed refrigerant can include methane, paragraph 73), and the second refrigerant comprises nitrogen (the second mixed refrigerant can contain nitrogen, paragraph 94).
With respect to claim 8, Seitter as modified teaches wherein the flow of the second refrigerant flowing into the cryogenic heat exchanger from the second refrigerant expansion part is to be configured to sequentially pass through, a cold heat exchange region, an intermediate heat exchange region and a warm heat exchange region, in the cryogenic heat exchanger (from 92, the refrigerant passes through 38, which from the entry into 38 to the outlet of 38 there can be considered a cold heat exchanger region on the coldest side of 38, an intermediate heat exchange region in the middle of 38 and a warm heat exchange region on the warmer side of 38).
Response to Arguments
Applicant's arguments filed 3/20/2026 have been fully considered but they are not persuasive.
Applicant argues, page 8 that modifying Seitter with would “fundamentally alter Seitter’s disclosed compression topology by inserting separate compressors on each divided flow line” which modification would change the principle operation in Seitter and Wyllie does not teach the amended limitation. This is not persuasive.
Applicant appears to be arguing that any change to Seitter’s configuration would not be possible as it would fundamentally change Seitter. The change as shown in the rejection above, would not fundamentally alter the operation of Seitter but would only result in a reduction in the amount of compression required by the present compressors in Seitter by allowing some of the compression to happen first in expanded driven compression, which would provide what would be predictable to one having ordinary skill in the art of a reduction in the overall power demand for compression within the system by providing some of the necessary compression through expansion, an expansion which is necessary, something that is well known to one having ordinary skill in the art. Further, contrary to applicant’s arguments, Wyllie teaches the exact configuration as claimed in regards to pre-compression of the two divided flows and mixing two divided flows before further passing them to a first compression part as claimed. The claims only require that after pre-compression at some point the two streams are mixed and compressed again, which is met by Wyllie and present in the modification.
Applicant argues, page 9 that there is no teaching or suggestion that such a modification would be “predictable, desirable, or compatible with Seitter’s mixed-refrigerant liquefaction system” and “the Office action only relies on a generalized statement that reducing power demand is desirable, without explaining why a person of ordinary skill would specifically implement pre-compression of at least two divided flows for the first refrigerant by at least two respective turbo-expanders”. This is not persuasive.
It is well known in the art that turbo expanders provided a reduction in overall power demand for a system, by recovering the energy of expansion. Based on the teaching of Wyllie it is shown that the power can be recovered utilizing the configuration that the claims refer to as pre-compression. Wyllie also explicitly provides teachings that using turbo-expanders is for reducing power demand (paragraphs 7, 76) and that using the configuration of Figure 5 is more efficient than other configurations (paragraph 92). Even without these teachings one having ordinary skill in the art would recognize the implicit and inherent power demand savings that would occur from providing part of the necessary refrigeration compression through energy recover from expansion. Seitter even contemplates using a hydraulic turbine (paragraph 52) for such expansion, which is expansion that produces mechanical work and as such would be considered a turboexpander as well. Although a hydraulic turbine is generally considered a turbine which powers water, within the cryogenic art and that it is expanding a gas which generates power, a hydraulic turbine in the context of Seitter is an expansion turbine, also called a turboexpander (see Mak et al. US 20170131027, Figure 1, 150, paragraph 25 which shows what is referred to as a hydraulic turbine which expands treated gas, paragraph 17 and as such is an expansion turbine or a turboexpander).
Applicant argues, page 10 that “Seitter does not disclose a second refrigerant turboexpander that comprises both an expansion part and a pre-compression part” and only disclosed “a Joule-Thomson valve or hydraulic turbine, after which the second refrigerant warms in warming pass 42 and is then compressed by a separate compressor system” which does not meet the limitation as claimed. This is not persuasive.
The claims do not require that the second refrigerant turbo expander is used to drive the second refrigerant pre-compression part, they only require that the second refrigerant turbo expander comprises a second refrigerant expansion part downstream of the cryogenic heat exchanger, and separately the claims require a second refrigerant pre-compression part for compression the second refrigerant coming from the second refrigerant turbo expander. This language differs from that of claim 1 which explicitly requires that the turbo expander explicitly is used to perform expansion and pre-compression and as such, the claim can be interpreted as shown in the rejection above, which does not teach that the turbo expander is used for compressing. A turboexpander is only required to produce work through expansion of a gas, also called an expansion turbine (which as shown above a hydraulic turbine meets), the mere recitation that a turboexpander is present does not provide a requirement that the work provided is compression Further, it should be noted that if the claim was amended requiring that the second refrigerant turbo expander is used in the same way as the first turbo expander, this it is well known in the art to provide such a configuration for the same reasons as in Wyllie.
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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to BRIAN M KING whose telephone number is (571)272-2816. The examiner can normally be reached Monday - Friday, 0800-1700.
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/BRIAN M KING/Primary Examiner, Art Unit 3763
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