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 .
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 9 February, 2026 is being considered by the examiner.
Response to Amendment
This Final Office Action is in response to Applicant’s Remarks/Amendments filed on 30 March, 2026. The amendments have been entered.
Disposition of Claim
Claims 1, 4-12, 14-16, 18-23 are pending.
Claims 2-3, 13, 17 have been cancelled.
Claim 23 is new.
Drawings
The drawings were received on 30 March, 2026. These drawings are acceptable, and overcome the objection at points 4(a)(i) – 4(a)(iv) of the drawings set forth at page 2 of the Non-Final Office Action mailed on 29 December, 2025.
With regards to the objection at points 4(b)(i) – 4(b)(ii), the drawings remain objected. Applicant notes the drawings show the reference characters “PI” and “LI” within “Figs. 2-5. For example in Fig. 2, “PI” is shown to be connected to “PIC” with a broken line, and “LI” is shown to be connected to “LIC” with a solid line”. However, such recitations are not legible, and Applicant is reminded of 37 CFR 1.84(k) which states, “The scale to which a drawing is made must be large enough to show the mechanism without crowding when the drawing is reduced in size to two-thirds in reproduction.” The recitation of these is not legible at 100% zoom of figures 2-5 (shown below), such that it would not be legible at two-thirds the size if reproduced at the time of reproduction thereof. For this, the drawings are objected based on illegibility of the reference characters.
Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. The figure or figure number of an amended drawing should not be labeled as “amended.” If a drawing figure is to be canceled, the appropriate figure must be removed from the replacement sheet, and where necessary, the remaining figures must be renumbered and appropriate changes made to the brief description of the several views of the drawings for consistency. Additional replacement sheets may be necessary to show the renumbering of the remaining figures. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
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Specification
Amendments to the specification and abstract were received on 30 March, 2026. These specification and abstract amendments are acceptable, and overcome the objection at points 4(c)(i) – 4(c)(ii) of the drawings set forth at page 3 of the Non-Final Office Action mailed on 29 December, 2025 and the objections at point 5(a)(i) at page 4 of the Non-Final Office Action mailed on 29 December, 2025.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claim(s) 16 and 18-19 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by CHOI (KR 10-2021-0023540 A – published 4 March, 2021; see English machine translation).
As to claim 16, CHOI discloses a boil-of gas reliquefaction method of a ship (par. [0001] and [0015]),
wherein a boil-off gas generated in an on-board storage tank (T) is compressed in a compressor (100) and is cooled to reliquefy a compressed boil-off gas through heat exchange(par. [0048]) in a heat exchanger (200) to which a refrigerant circulating along a refrigerant circulation line (CL) is supplied (par. [0049]-[0050])
the boil-off gas generated in the storage tank is heated by heat exchange through the heat exchanger and is introduced into the compressor (par. [0052]).
Furthermore, “when the reliquefaction system is not operated or a load of the reliquefaction system is low, all or some of the boil-off gas generated in the storage tank is heated in the heater along the temperature raising line bypassing the heat exchanger and is introduced into the compressor”, is a contingent system limitation which is not required by the claim. See MPEP § 2111.04 – II. The broadest reasonable interpretation of a method (or process) claim having contingent limitations requires only those steps that must be performed and does not include steps that are not required to be performed because the condition(s) precedent are not met. For example, assume a method claim requires step A if a first condition happens and step B if a second condition happens. If the claimed invention may be practiced without either the first or second condition happening, then neither step A or B is required by the broadest reasonable interpretation of the claim. If the claimed invention requires the first condition to occur, then the broadest reasonable interpretation of the claim requires step A. If the claimed invention requires both the first and second conditions to occur, then the broadest reasonable interpretation of the claim requires both steps A and B. At best, the limitation does not require the condition “when a reliquefaction system is not operated or a load of the reliquefaction system is low” and thereby, does not require the method step claimed. The disclosure of CHOI sets forth the requirements of the claimed invention set forth within claim 16.
As to claim 18, CHOI further discloses wherein:
the refrigerant circulating(par. [0049]) in the refrigerant circulation line is compressed in a refrigerant compression part(400a, 400b, 400c, 400d), cooled through the heat exchanger (200), and is expanded and cooled (par. [0050]) in a refrigerant expansion device (300) to be supplied as a cold heat source to the heat exchanger(par. [0050]).
As to claim 19, CHOI further discloses wherein the compressor compresses the boil-off gas to a fuel supply pressure of a propulsion engine provided to the ship (par. [0004]-[0010], [0025], [0035], [0043]-[0044], [0057]) and the propulsion engine is supplied with boil-off gas compressed to 10 to 20 bara (par. [0057], in view of atmospheric pressure at sea level being generally 1bar, such that CHOI provides at least 16bara (wherein bara = barg + atmospheric pressure) when a X-DF engine is installed).
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.
Claim(s) 1 and 4-8 is/are rejected under 35 U.S.C. 103 as being unpatentable over CHOI (KR 10-2021-0023540 A – published 4 March, 2021; see English machine translation), in view of LIM (KR 10-2018-0033734 A – published 4 April, 2018; see English machine translation).
As to claim 1, CHOI discloses a boil off gas reliquefaction system (par. 1), comprising:
a compressor(100) configured to compress a boil-off gas generated from liquefied gas(par. [0048]) stored in an on-board storage tank(T);
a heat exchanger(200) configured to cool a compressed gas compressed in the compressor(par. [0048]);
a refrigerant circulation line(CL) in which a refrigerant supplied to the heat exchanger circulates(par. [0049]);
a gas supply line (GL) extending from the storage tank (T) to the compressor (100) through the heat exchanger (200); and
a gas supply valve provided to the gas supply line (figures 1-4),
wherein the boil-off gas generated in the storage tank is introduced into the compressor(par. [0052]) along the gas supply line after undergoing heat exchange with the compressed gas in the heat exchanger (figures 1-4; par. [0048] and [0059]).
CHOI, however, does not disclose a temperature raising line extended from the storage tank to the compressor; and a heater provided to the temperature raising line, wherein the heater heats the boil-off gas to a suitable temperature of the compressor. Second, CHOI provides depiction of a gas supply valve along the gas supply line, as shown in figures 1-4, but CHOI does not expressly disclose wherein the gas supply valve regulates a flow rate of the boil-off gas to be introduced into the compressor through the heat exchanger. Lastly, CHOI does not disclose a bypass valve provided to the temperature raising line to regulate the flow rate of boiling-off gas to be introduced into the compressor through the heater, and wherein the reliquefaction system is not operated or a load of the reliquefaction system is low, all or some of the boil-off gas generated in the storage tank is heated in the heater along the temperature raising line bypassing the heat exchanger and is introduced into the compressor.
LIM, however, is within the field of endeavor provided a boil off gas reliquefaction system (par. [0005]-[007]). LIM teaches a line(L2; par. [0039]) which carries a boil off gas generated from liquefied gas stored in an on-board storage tank (10). LIM teaches wherein there is a temperature raising line (L6; par. [0064]; figure 4) extending from the storage tank to a compressor downstream (figure 4; 60; par. [0052]), and a heater (53; par. [0053]; figure 4) provided on the temperature raising line (figure 4), wherein the heater heats the boil-off gas to a suitable input temperature of the compressor (par. [0052]; par. [0100]-[0103]). LIM provides these teachings for the purpose of generating room temperature gas which is widely used for fuel (par. [0003], in view of par. [0100]-[0103]). LIM teaches the gas supply line (L2) including a gas supply valve (542; par. [0059]-[0060]) which regulates the flow rate of boil-off gas(par. [0148] and [0163]-[0165]) supplied to the compressor(60) from a heat exchanger(52a) to control the flow of the gas within various portions of the system based on temperature measurements received (par. [0163]-[0164]) to achieve the desired temperature and pressure necessary to operate an engine that uses the liquefied gas as fuel (par. [0004]), while ensuring reliability and stability of the system (par. [0170]). LIM teaches a bypass valve (541; par. [0148]-[0149]; figure 4) provided to the temperature raising line (L6) to regulate the flow rate of boil-off gas to be introduced into (par. [0148]-[0150] and [0163]-[0165]) the compressor (60) through the heater (53), such that all or some of the boil-off gas is heated by the heater along the temperature raising line bypassing the heat exchanger and introduced into the compressor (figure 4). Again, LIM teaches controlling the flow of the gas within various portions of the system based on temperature measurements received (par. [0163]-[0164]) to achieve the desired temperature and pressure necessary to operate an engine that uses the liquefied gas as fuel (par. [0004]), while ensuring reliability and stability of the system (par. [0170]). Therefore, it would have been obvious to one having ordinary skill within the art, prior to the date the invention was effectively filed, to modify CHOI to include the claimed structure, as taught by LIM, for these reasons.
More so, “when the reliquefaction system is not operated or a load of the reliquefaction system is low, all or some of the boil-off gas generated in the storage tank is heated in the heater along the temperature raising line bypassing the heat exchanger and is introduced into the compressor”, is a contingent system limitation for which the combination of CHOI, in view of LIM, is fully capable of performing should the conditions be present. See MPEP § 2111.04 – II. The broadest reasonable interpretation of a system (or apparatus or product) claim having structure that performs a function, which only needs to occur if a condition precedent is met, requires structure for performing the function should the condition occur. The system claim interpretation differs from a method claim interpretation because the claimed structure must be present in the system regardless of whether the condition is met and the function is actually performed. The combination of CHOI, in view of LIM, for the reasons provided, effectively teach the required structure of the claimed invention set forth within claim 1, and is fully capable of performing the functions claimed, as set forth above, should the conditions be present. Therefore, the combination set forth effectively teaches the claimed invention.
As to claim 4, CHOI, as modified, discloses further comprising:
a refrigerant compression part(400a, 400b, 400c, 400d) provided to the refrigerant circulation line (figure 4) and configured to compress the refrigerant discharge after heat exchanger in the heat exchanger (par. [0049]);and
a refrigerant expansion device(300) provided to the refrigerant circulation line(figure 4) and configured to expand and cool the refrigerant to supply the expanded and cooled refrigerant to the heat exchanger (par .[0050]),
wherein the refrigerant in the refrigerant circulation line is compressed in the refrigerant compression part, is cooled through the heat exchanger, and is expanded and cooled in the refrigerant expansion device to be supplied as a cold heat source to the heat exchanger (par. [0050]).
As to claim 5, CHOI, as modified, discloses wherein four streams (figure 1-4) undergo heat exchanger in the heat exchanger (par. [0052] and [0059]), the four streams comprise a stream of the compressed gas compressed in the compressor (figures 1-4; par. [0048] and [0059]), a stream of the refrigerant expanded and cooled in the refrigerant expansion device (par. [0050]), a stream of uncompressed boil-off gas to be supplied from the storage tank to the compressor along the gas supply line (par. [0052]), and a stream of the refrigerant compressed in the refrigerant compression part (par. [0050]).
As to claim 6, CHOI, as modified, discloses wherein the refrigerant compression part is connected to the refrigerant expansion device to compress the refrigerant by receiving expansion energy of the refrigerant from the refrigerant expansion device (par. [0023]-[0024]).
As to claim 7, CHOI, as modified, discloses wherein the compressor is configured to compress the boil-off gas to a fuel supply pressure of a propulsion engine provided to a ship (par. [0004]-[0010], [0025], [0035], [0043]-[0044], [0057]) and the propulsion engine is supplied with boil-off gas compressed to 10 to 20 bara (par. [0057], in view of atmospheric pressure at sea level being generally 1bar, such that CHOI provides at least 16bara (wherein bara = barg + atmospheric pressure) when a X-DF engine is installed).
As to claim 8, CHOI, as modified, discloses wherein:
a decompressor (500) configured to receive the compressed gas cooled by the heat exchanger to depressurize the compressed gas (par. [0060]-[0061]); and
a gas-liquid separator(600) configured to receive a depressurized boil-off gas from the decompressor to separator the depressurized boil-off gas into gaseous and liquid phrases (par. [0060] and [0062]-[0063]),
wherein flash gas separated in the gas-liquid separator is joined to an uncompressed boil-off gas stream to be introduced into the compressor upstream of the heat exchanger (par. [0063]; figure 4) and liquefied gas separated in the gas-liquid separator is returned to the storage tank(par. [0062]).
Claim(s) 9-12, 14-15, 20-22 is/are rejected under 35 U.S.C. 103 as being unpatentable over CHOI (KR 10-2021-0023540 A – published 4 March, 2021; see English machine translation), in view of PARK (KR 102120541 B1 – published 9 June, 2020; see English machine translation).
As to claim 9, CHOI discloses an off-gas treatment system of a reliquefaction apparatus of a ship (par. [0001] and [0015]), comprising:
a compressor (100; par. [0048]) configured to compress a boil-off gas generated from a liquefied gas stored in an on-board storage tank (T),
a reliquefaction line (see figure 4; RL, which includes the separator, 600, and heat exchanger, 200, disposed along the reliquefaction line) extending from the compressor to the storage tank to reliquefy the boil-off gas and return the reliquefied gas to the storage tank (figure 4; par. [0048]);
a heat exchanger (200) provided to the reliquefaction line and configured to cool the boil-off gas compressed in the compressor (par. 48 ang 51; figure 4); and
a separator (600) provided to the reliquefaction line (figure 4; par. [0060] and [0062]-[0063]) and configured to separate the boil-off gas cooled through the heat exchanger into gaseous and liquid phases to supply the reliquefied gas to the storage tank(par. [0062]-[0063]);
an off-gas combustion line configured to supply off-gas separated in the separator (FL; par. [0063]);
a vapor main (GL) configured to discharge the boil-off gas from the storage tank (figure 4).
wherein the GCU(par. [0007]-[0010] and [0043]-[0044]) configured to receive the boil-off gas from the vapor mains (par. [0043]-[0044], [0051], and [0057]; figure 4).
However, CHOI does not expressly disclose wherein the separated off-gas is supplied to the gas combustion unit (GCU), together with the boil-off gas, such that the GCU burns the off-gas and boil-off gas.
PARK, however, is within the field of endeavor provided an off-gas treatment system of a reliquefaction system of a ship (par. [0001]). PARK teaches a separated off gas(par. [0165]-[0166]) generated by a separator (50) is supplied to a GCU (3b; figure 10; par. [0169]), such that the GCU burns the off-gas (par. [0029]). PARK teaches a vapor main (21) which discharges boil-off gas from the storage tank (10) to a GCU (3b; figure 10), in addition to separated off gas (par. [0165]-[0166]) generated by a separator (50) is supplied to the GCU (3b; figure 10; par. [0169]). PARK provides supplying such source of off-gas to the GCU enables providing fuel to the GCU for the purpose of covering the internal power load of the ship (par. [0029]). Therefore, it would have been obvious to one having ordinary skill within the art, prior to the date the invention was effectively filed to modify CHOI, in view of PARK, with the teachings for these purposes.
As to claim 10, CHOI, as modified, does not further provide the requirements set forth by claim 9.
However, PARK, further, teaches a heater (517) provided to the off-gas combustion line (515) to heat the off-gas to be supplied to the GCU (par. [0180]-[0181]), an off-gas recirculation line (51) branched from the off-gas combustion line (figure 10) upstream of the heater and extending to the vapor main (21; par. [071]); and an overpressure protection valve (511) provided to the off-gas recirculation line (par. [0219], [0230], [0233]; figure 10). PARK provides the inclusion of the off-gas recirculation line provides heat exchange, in addition to ensuring a certain level of operation and increased efficiency (par. [0071] – [0072]; figure 10). Second, the inclusion of the heater allows heating of the cooled fuel to be delivered to the GCU (par. [0181]), while the overpressure protection valve controls the flow of the off-gas upstream or downstream of the heat exchanger (par. [0071]). Therefore, it would have been obvious to one having ordinary skill within the art, prior to the date the invention was effectively filed to modify CHOI, in view of PARK, with these discussed teachings for these reasons.
As to claim 11, CHOI, as modified, previously taught the inclusion of supplying off-gas to the vapor main along the off-gas recirculation line (see rejection of claim 10), but CHOI does not disclose wherein this is through the overpressure protection valve.
More so, PARK teaches wherein this supply is through the overpressure protection valve (511; figure 10), again, for the reason of controlling the flow of the off-gas upstream and downstream of the heat exchanger (par. [0071])). Therefore, it would have been obvious to one having ordinary skill within the art, prior to the date the invention was effectively filed to modify CHOI, in view of PARK, with these discussed teachings for these reasons.
Second, the recitation of “wherein, during startup of the GCU or upon interruption of the GCU, the off-gas separated in the separator is supplied to the vapor main along the off-gas recirculation line through the overpressure protection valve”, is a contingent system limitation for which the combination of CHOI, in view of PARK, is fully capable of performing should the conditions be present. See MPEP § 2111.04 – II. The broadest reasonable interpretation of a system (or apparatus or product) claim having structure that performs a function, which only needs to occur if a condition precedent is met, requires structure for performing the function should the condition occur. The system claim interpretation differs from a method claim interpretation because the claimed structure must be present in the system regardless of whether the condition is met and the function is actually performed. The combination of CHOI, in view of PARK, for the reasons provided, effectively teach the required structure of the claimed invention set forth within claim 11, and is fully capable of performing the functions claimed, as set forth above, should the conditions be present. Therefore, the combination set forth effectively teaches the claimed invention.
As to claim 12, CHOI, as modified, further discloses comprising:
a refrigerant circulation part (CL) in which a refrigerant to undergo heat exchange with the boil-off gas in the heat exchanger circulates (figure 1; par. [0050] and [0053]),
wherein the refrigerant in the refrigeration circulation part is nitrogen (par. [0053]).
As to claim 14, CHOI, as modified, further discloses comprising:
a gas supply line (SL) extending from the vapor main to an on-board engine (E; figure 4).
However, CHOI does not further disclose wherein the off-gas is delivered to the vapor main along the off-gas recirculation line to be supplied as fuel to the engine together with the boil-off gas discharged from the storage tank.
PARK, however, further teaches wherein the off-gas is delivered to the vapor main(21) along the off-gas recirculation line(51) to be supplied as fuel to the engine together with the boil-off gas discharged from the storage tank (figure 10). PARK provides the inclusion of the off-gas recirculation line provides heat exchange, in addition to ensuring a certain level of operation and increased efficiency (par. [0071] – [0072]; figure 10) with combination to the boil-off gas within the vapor main. Therefore, it would have been obvious to one having ordinary skill within the art, prior to the date the invention was effectively filed to modify CHOI, in view of PARK, with these discussed teachings for these reasons.
As to claim 15, CHOI, as modified, does not expressly disclose the requirements of the claim.
However, PARK further teaches including ga liquefied gas supply line (80) extending from the storage tank (10) to the gas supply line (par. [0240]), and a vaporizer (85) provided to the liquefied gas supply line (figure 14) and configured to receive the liquefied gas from the storage tank to vaporize the liquefied gas (par. [0242]-[0243]). Specifically, PARK states this addition enables control of the boil-off gas and liquefied gas in various ways based on the operating status of the ship (par. [0244]). Therefore, it would have been obvious to one having ordinary skill within the art, prior to the date the invention was effectively filed to modify CHOI, in view of PARK, with these discussed teachings for these reasons.
Second, the recitation of “wherein, when a mixture of the off-gas and the boil-off gas of the storage tank does not satisfy a calorific value of the engine, the liquefied gas from the storage tank is forcibly vaporized and supplied to the mixture”, which is a contingent system limitation for which the combination of CHOI, in view of PARK, is fully capable of performing should the conditions be present. See MPEP § 2111.04 – II. The broadest reasonable interpretation of a system (or apparatus or product) claim having structure that performs a function, which only needs to occur if a condition precedent is met, requires structure for performing the function should the condition occur. The system claim interpretation differs from a method claim interpretation because the claimed structure must be present in the system regardless of whether the condition is met and the function is actually performed. The combination of CHOI, in view of PARK, for the reasons provided, effectively teach the required structure of the claimed invention set forth within claim 15, and is fully capable of performing the functions claimed, as set forth above, should the conditions be present. Therefore, the combination set forth effectively teaches the claimed invention.
As to claim 20, CHOI discloses an off-gas treatment method for a reliquefaction apparatus of a ship (par. [0001] and [0015]),
wherein a boil-off gas generated in an on-board storage tank(T) is compressed in a compressor (100; par. [0048]);
wherein the boil-off gas compressed in the compressor is cooled in a heat exchanger (200) to be reliquefied (par. [0048]), and is separated into gaseous and liquid phases(par. [0060]-[0063]; figure 4) through a separator (600) to be returned to the storage tank (T); and
wherein the boil-off gas generated in the storage tank is discharged to the vapor main and supplied to the GCU(par. [0007]-[0010], [0043]-[0044], [0051], and [0057]; figure 4).
However, CHOI does not expressly disclose wherein the separated off-gas is supplied to the gas combustion unit (GCU), together with the boil-off gas, such that the GCU burns the off-gas and boil-off gas.
PARK, however, is within the field of endeavor provided an off-gas treatment system of a reliquefaction system of a ship (par. [0001]). PARK teaches a separated off gas(par. [0165]-[0166]) generated by a separator (50) is supplied to a GCU (3b; figure 10; par. [0169]), such that the GCU burns the off-gas (par. [0029]). PARK teaches a vapor main (21) which discharges boil-off gas from the storage tank (10) to a GCU (3b; figure 10), in addition to separated off gas (par. [0165]-[0166]) generated by a separator (50) is supplied to the GCU (3b; figure 10; par. [0169]). PARK provides supplying such source of off-gas to the GCU enables providing fuel to the GCU for the purpose of covering the internal power load of the ship (par. [0029]). Therefore, it would have been obvious to one having ordinary skill within the art, prior to the date the invention was effectively filed to modify CHOI, in view of PARK, with the teachings for these purposes.
As to claim 21, the recitation of “wherein, during startup of the GCU or upon interruption of the GCU, the off-gas separated in the separator is supplied to the vapor main”, is a contingent system limitation which is not required by the claim. See MPEP § 2111.04 – II. The broadest reasonable interpretation of a method (or process) claim having contingent limitations requires only those steps that must be performed and does not include steps that are not required to be performed because the condition(s) precedent are not met. For example, assume a method claim requires step A if a first condition happens and step B if a second condition happens. If the claimed invention may be practiced without either the first or second condition happening, then neither step A or B is required by the broadest reasonable interpretation of the claim. If the claimed invention requires the first condition to occur, then the broadest reasonable interpretation of the claim requires step A. If the claimed invention requires both the first and second conditions to occur, then the broadest reasonable interpretation of the claim requires both steps A and B. At best, the limitation does not require the condition “during startup of the GCU or upon interruption of the GCU” and thereby, does not require the method step claimed. The combination of CHOI, as modified, teaches the requirements of the claimed invention set forth within claim 21.
As to claim 22, the recitation “wherein the off-gas supplied to the vapor main is mixed with the boil-off gas discharged from the storage tank to the vapor main or with a gas produced through forced vaporization of liquefied gas in the storage tank to be supplied as fuel to an on-board engine in accordance with a calorific value required for the engine” is dependent from the contingent limitation set forth within claim 21. As the conditions required for the steps to take place are not positively recited, the claim limitations are not required. See MPEP § 2111.04 – II. The broadest reasonable interpretation of a method (or process) claim having contingent limitations requires only those steps that must be performed and does not include steps that are not required to be performed because the condition(s) precedent are not met. For example, assume a method claim requires step A if a first condition happens and step B if a second condition happens. If the claimed invention may be practiced without either the first or second condition happening, then neither step A or B is required by the broadest reasonable interpretation of the claim. If the claimed invention requires the first condition to occur, then the broadest reasonable interpretation of the claim requires step A. If the claimed invention requires both the first and second conditions to occur, then the broadest reasonable interpretation of the claim requires both steps A and B. The combination of CHOI, as modified, teaches the requirements of the claimed invention set forth within claim 22.
Allowable Subject Matter
Claim 23 is allowable.
The following is a statement of reasons for the indication of allowable subject matter:
Reasons for indicating allowable subject matter have been previously provided at pages 23-24 of the Non-Final Office Action mailed on 29 December, 2025. These reasons are incorporated herein by reference, as they pertain to the subject matter presented within newly presented, independent claim 23.
Response to Arguments
Claim Rejections - 35 USC § 112
Applicant’s arguments, see pages 5-6, 8-9, and 12 of Applicant’s Remarks/Amendments , filed 30 March, 2026, with respect to the rejection of claims 7, 11, 18, and 21-22 under 35 U.S.C. 112(b) have been fully considered and are persuasive. The above-referenced rejection of claims 7, 11, 18, and 21-22 have been withdrawn.
Claim Rejections - 35 USC § 103
Applicant's arguments filed 30 March, 2026 with respect to the rejection of claims 1, 9, and 16, and the dependents thereof, have been fully considered but they are not persuasive.
At pages 12-13, Applicant alleges neither CHOI nor LIM provides “the boil-off gas is heated and supplied to the compressor when the reliquefaction system is not operated or when the load of the reliquefaction system is low”, such that the Applicant concludes the prior art does not render obvious “when the reliquefaction system is not operated or a load of the reliquefaction system is low, all or some of the boil-off gas generated in the storage tank is heated in the heater along the temperature raising line bypassing the heat exchanger and is introduced into the compressor” of claim 1 and claim 16. However, the claim limitation, as stated within the rejections set forth at pages 9-10 and 13-14 of the Non-Final Office action mailed 29 December, 2025, the limitation is a contingent limitation. Under broadest reasonable interpretation of a contingent limitation within a system claim (such as that within claim 1), the claim merely requires the structure that performs the function should the condition occur. See MPEP § 2111.04 – II. This is consistent with the interpretation of such system claims where the manner of operating the device does not differentiate apparatus claims from the prior art. See MPEP § 2114 – II. As such, the combination of CHOI and LIM teach the structural requirements of the claimed invention which are capable of performing the functions of “when the reliquefaction system is not operated or a load of the reliquefaction system is low, all or some of the boil-off gas generated in the storage tank is heated in the heater along the temperature raising line bypassing the heat exchanger and is introduced into the compressor”. Second, under broadest reasonable interpretation of a contingent limitation within a method claim (such as that within claim 16), the claim only requires the method steps which are positively recited, i.e., the conditions precedent for the method step to occur do occur. See MPEP § 2111.04 – II. In this case, the limitation “when the reliquefaction system is not operated or a load of the reliquefaction system is low, all or some of the boil-off gas generated in the storage tank is heated in the heater along the temperature raising line bypassing the heat exchanger and is introduced into the compressor” is not required because it does not set forth that the reliquefaction system is not operated or the load of the system is, in fact, low. As such, the combination of CHOI and LIM teach the requirements of the method claim. For these reasons, consistent with the interpretation set forth within the Non-Final Office Action mailed on 29 December, 2025, the arguments with regards to claims 1 and 16 are not persuasive.
At page 13, Applicant argues against the combination of prior art, set forth at pages 15-16 of the Non-Final Office Action mailed on 29 December, 2025, with regards to claim 9. Specifically, Applicant argues CHOI does not disclose “wherein the GCU is configured to receive the boiloff gas from the vapor main and burn the off-gas together with the boil-off gas”, and further argues, “The Office Action further cited Park which discloses an evaporation gas reliquefaction system. In Park gas discharged from a gas-liquid separate is burned in a GCU. However, Park does not recognize the problem that the gas separated by the gas-liquid separated contains a large amount of nitrogen and is therefore difficult to burn in the GCU, and thus, does not disclose or suggest burning the separated gas together with evaporation gas”. However, recognizing the problem cited by the Applicant is not a requirement to set forth a prior art rejection under 35 U.S.C. 103. See MPEP § 2141. Furthermore, PARK does, in fact, teach “wherein the GCU is configured to receive the boil-off gas from the vapor main and burn the off-gas together with the boil-off gas”. PARK teaches a vapor main (21) which discharges boil-off gas from the storage tank (10) to a GCU (3b; figure 10), in addition to separated off gas (par. [0165]-[0166]) generated by a separator (50) is supplied to the GCU (3b; figure 10; par. [0169]). As such, these teachings of PARK necessarily provide wherein the boil-off gas and the off-gas from the separator are supplied together to the GCU. For these reasons, the arguments are not persuasive.
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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/JENNA M MARONEY/Primary Examiner, Art Unit 3763 4/17/2026
JENNA M. MARONEY
Primary Examiner
Art Unit 3763
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