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 .
Priority
Acknowledgment is made of applicant's claim for foreign priority based on an application filed in France on 3 May 2024. It is noted, however, that applicant has not filed a certified copy of the FR2404643 application as required by 37 CFR 1.55.
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 1 is 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.
Regarding Claim 1, the claim contains the following method steps for filling a plurality of cryogenic liquid receiving tanks comprising cryogenic liquid fuel tanks of vehicles:
“transferring a first quantity of cryogenic liquid from a first source tank to a first receiving tank, and simultaneously transferring a first quantity of vaporization gas present in the first receiving tank to the first source tank;
verifying whether a distribution condition is met, wherein the distribution condition comprises determining whether a pressure in the first source tank is lower than a predetermined pressure threshold; and
upon verification that the distribution condition is met, transferring a second quantity of cryogenic liquid from the first source tank to a second receiving tank, and simultaneously transferring of a second quantity of vaporization gas present in the second receiving tank to the first source tank.”
One of ordinary skill in the art would see that this claim requirement (e.g., pressure below a predetermined threshold) encompasses the likely scenario wherein the source tank does not have enough fuel to fill a second tank after filling the first tank.
Although Applicant’s disclosure repeats the claim language verbatim (see Specification, at least at page 3, line 20, pg. 8, lines 8-20, and pg. 12, line 5, and Fig. 1, wherein the method step is additionally taught as part of verification step 120), the disclosure offers no reason or rationale for performing the action of verification, does not provide an example range of pressure thresholds, does not identify any structure or component (such as a venting valve or other mechanism) used to physically limit the pressure of the source tank below a predetermined threshold, or offer any indication of novel or unexpected results for only initiating fuel flow from the source tank when the pressure of the source tank is below a predefined threshold.
Examiner acknowledges the limitation of Claim 10, which additionally requires “a pump configured to make it possible to pump the cryogenic liquid during the cryogenic liquid transfer step.” Examiner additionally notes the presence of a pump within the disclosure (see Specification, pg. 5, line 11, pg. 10, line 18, and pg. 12, line 14).
However, the disclosure again merely echoes the claim verbiage, and Examiner further notes:
1) there is no mention of the pump being utilized for the (likely) scenario wherein the source tank pressure is lower than the receiving tank pressure, and
2) Claim 1 does not require the use of any pump or similar structure.
In light of the above, Examiner concludes that Claim 1 fails to meet the written description requirement of 35 USC 112(a), since the claim specifies a desired result (filling of a second tank after verification that the pressure in the source tank is below a predetermined pressure threshold), but the disclosure fails to sufficiently identify how the function is performed or the result is achieved, and does not describe the claimed invention so that one skilled in the art can recognize what is claimed.
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 1-12 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.
Regarding Claim 3, the claim contains an instance of the word “preferably”, which renders the scope of the claim indefinite. It is unclear if the requirement (i.e., “the condition that the liquid level in the first source tank is higher than a predetermined liquid level threshold… preferably being checked before the distribution condition relating to the pressure in the first source tank”) is actually required.
Regarding Claim 12, the claim contains the following phrase/limitation:
“…if the distribution condition is not respected, the first source tank and the tractor vehicle being moved to the first zone of the airport, at the using the tractor vehicle.”
As written, the phrase is incomprehensible in American English, and appears to be an idiomatic translation from another language. Additionally, it is unknown if Applicant intends to claim a method step such that if the distribution condition established at antecedent Claim 1 is not met (e.g., the first source tank has a pressure above a predetermined threshold), then the source tank and the tractor vehicle is moved to the first zone of the airport by using the tractor vehicle”, or some other method step.
In the interests of compact prosecution, and in light of Applicant’s entire disclosure, Examiner interprets this phrase/limitation as requiring the movement of an over-pressurized tank by a tractor vehicle to a first zone of an airport, wherein said first zone is “intended for parking the source tanks and the tractor vehicle.”
However, correction is required.
Regarding Claims 1-12, the scope of Claim 1 is indefinite for the reasons described above in the rejection of Claim 1 under 35 USC 112(a). Claims 2-12 depend upon Claim 1, and therefore suffer the same deficiencies.
Further regarding Claims 1-12, the claims contain several instances of the component “tank”, with differing descriptive nomenclature that renders the claim(s) indefinite due to either a lack of antecedent basis and/or uncertainty as to the scope of the claim and overall claim set. Specifically:
- The preamble of independent Claim 1 establishes a “method using a plurality of mobile source tanks, the method comprising the following steps…”. Examiner notes that this is the only instance of the phrase “mobile source tanks” in the entire claim set, and all dependent claims ultimately depend upon Claim 1.
- However, Claim 1 also establishes said method as requiring “a first source tank” and “a first receiving tank”. As written, it is unclear if the first source and receiving tanks of Claim 1 (and its dependent claims) are the same as the “mobile source tanks” established in the preamble, or another group of tanks.
- The above uncertainty is particularly emphasized for the “first receiving tank”, and the “second receiving tank” also established at Claim 1; it is unclear if these “receiving tanks” are also “mobile tanks” as possibly inferred in the preamble.
- Additionally, the dependent claims make several references to “the first source tank”, “the second source tank”, and “the source tank”. It is unclear Applicant considers these two components to be the same “tank”, or different tanks. The phrase “the source tank” appears in Claims 3-4, 6, 8-10, and 12.
- Similarly, Claims 9 and 11 reference “the receiving tank”; it is unclear if this component is the same as either one of the “first” or “second source tank”.
Claims 2-12 ultimately depend upon Claim 1, and therefore suffer the same Claim 1 deficiencies in addition to the others as noted above. Applicant is requested to thoroughly review the entire claim set, and standardize the nomenclature with regards to the “tanks” to comply with the requirements of 35 USC 112(b).
In the interests of compact prosecution, and in light of Applicant’s disclosure within the Specification and Drawings, Examiner applies the following broadest reasonable interpretation of the claim set, with regards to the “tanks”:
- In the claims, all references to “source tanks” and “receiving tanks” are equated as being “mobile tanks”.
- In the claims, there are multiple “mobile source tanks” and multiple “mobile receiving tanks”.
- With specific regards to Claims 1-10, Examiner regards these multiple “mobile source tanks” and multiple “mobile receiving tanks” as being interchangeable; i.e., “a tank is a tank”, and it is extremely well known for tanks to be “mobile”. Examiner acknowledges that Claims 11 and 12 further require the receiving tanks to be “aircraft cryogenic liquid fuel tanks”, which are, by definition, mobile.
- Claims 9-10 and 12 additionally require a “tractor vehicle” used in conjunction with one or more “mobile tanks”. As mobile fuel trucks are extremely well known to the prior art, and are expressly designed to transport and distribute fuel from an attached tank, any teaching of a fuel truck, further comprising a pump or similar equipment, will anticipate this requirement.
Claim Rejections - 35 USC § 102
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 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 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.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claims 1-2, 5, and 9-10 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Light et al. (US 2023/0160537).
Regarding Claim 1,
Examiner makes the following broadest reasonable interpretation of the claim language within Claim 1.
Claim 1 contains the following method steps for filling a plurality of cryogenic liquid receiving tanks comprising cryogenic liquid fuel tanks of vehicles:
“transferring a first quantity of cryogenic liquid from a first source tank to a first receiving tank, and simultaneously transferring a first quantity of vaporization gas present in the first receiving tank to the first source tank;
verifying whether a distribution condition is met, wherein the distribution condition comprises determining whether a pressure in the first source tank is lower than a predetermined pressure threshold; and
upon verification that the distribution condition is met, transferring a second quantity of cryogenic liquid from the first source tank to a second receiving tank, and simultaneously transferring of a second quantity of vaporization gas present in the second receiving tank to the first source tank.”
In plain language, Examiner interprets these method steps of Claim 1 as describing the sequential filling of first and second receiving tanks from a single source tank. According to the claim language above, the filling of the second receiving tank only occurs if the pressure within in the source tank is below a predetermined pressure. Prior to this second filling, a verification step is made to ensure the pressure within the source tank is below said predetermined pressure.
The claim language above has support within Applicant’s Specification at least at page 3, line 20, pg. 8, lines 8-20, and pg. 12, line 5, and the method step is additionally taught as part of verification step 120, shown at Fig. 1. However, Examiner notes that Applicant’s disclosure merely echoes the claim language, and provides no reason or rationale for performing the action of verification, does not provide an example range of pressure thresholds, does not identify any structure or component (such as a venting valve or other mechanism) used to physically limit the pressure of the source tank below a predetermined threshold, nor offer any indication of novel or unexpected results for only initiating fuel flow from the source tank when the pressure of the source tank is below a predefined threshold.
During a clarification interview conducted with Attorney Murray on 10 June 2026 (see attached summary), the attorney clarified that initiating fuel flow after verifying that the pressure in the source tank is below a predefined threshold is accomplished in the interests of safety, and to prevent filling from an over-pressurized tank, wherein over-pressurization could occur from the receipt of boil-off gas from the recipient tank(s).
In light of the broadness of the claim language of Claim 1 (which would literally include situations wherein the pressure in the source tank is so low that it could not fill a second tank), the lack of detail within the disclosure with regards as to how this method step is achieved, the lack of criticality of this step as written in the disclosure, and in further light of the attorney’s verbal clarification, Examiner makes the following broadest reasonable interpretation of the claim language:
Refueling of a second tank can only occur when two conditions are met:
1) the source and receiving tank pressures are both below a predefined pressure threshold that prevents over-pressurization of either tank, thereby mitigating the risks of tank failure, and
2) the source tank either has a pressure greater than that of the receiving tank(s), or utilizes a pump or similar component to facilitate fluid flow into the receiving tank(s).
Examiner asserts that avoiding over-pressurization of any pressurized tank is an extremely well-known process, normally accomplished for safety reasons by one of ordinary skill in the art through tank venting means and pressure monitoring. Examiner also asserts that it is well known to one of ordinary skill in the art to constantly monitor the pressurization of tanks and/or fueling systems, relieving pressure as necessary in order to prevent catastrophic tank failure and/or explosions.
Therefore, Examiner interprets the Claim 1 limitation of “verifying whether a distribution condition is met, wherein the distribution condition comprises determining whether a pressure in the first source tank is lower than a predetermined pressure threshold; and upon verification that the distribution condition is met, transferring a second quantity of cryogenic liquid from the first source tank to a second receiving tank” as being anticipated by:
- any prior art that teaches pressure control of a source tank after delivery of fuel to a receiving tank, to include pressure building within and/or venting of said source tank, and/or
- any prior art that teaches the automatic monitoring and venting of source tank(s) and/or fluid conduits leading into the source tank during the normal course of filling a receiving tank.
With either of the above configurations, the source tank would have a (verified) pressure set below a predetermined pressure threshold prior to the commencement of filling of the second tank, and therefore would read upon the Claim 1 limitation.
Further regarding Claim 1, as interpreted above, Light et al. discloses a method for filling a plurality of cryogenic liquid receiving tanks comprising cryogenic liquid fuel tanks of vehicles, the cryogenic liquid comprising liquid hydrogen (hydrogen is listed as a fuel for multiple tanks at para 66), the method using a plurality of mobile source tanks (a tank as part of trailer 10 introduced at paras 205 and 208. Although these paragraphs describe “the trailer 10”, para 310 additionally teaches “The singular forms “a”, “an” and “the” include plural referents, unless the context clearly dictates otherwise.” Examiner therefore interprets the teachings of Light et al. as encompassing “a plurality of mobile source tanks” as claimed here.)
the method comprising the following steps:
- transferring a first quantity of cryogenic liquid from a first source tank to a first receiving tank, and simultaneously transferring a first quantity of vaporization gas present in the first receiving tank to the first source tank (see Light et al., paras 208-209, wherein a first source tank is disclosed as part of trailer 10, a first receiving tank is disclosed as “final vessel 12”, liquid flow to final vessel 12 is accomplished by pump 6, and returning vaporization gas flow is explicitly described at para 209: "While liquid is flowing from the trailer 10 to the final vessel 12, gas hydrogen flows from the final vessel back to the trailer via gas hose 4")
- verifying whether a distribution condition is met, wherein the distribution condition comprises determining whether a pressure in the first source tank is lower than a predetermined pressure threshold
(See Examiner’s interpretation above. Light et al. explicitly teaches controlling the pressure in the source tank after delivery to a first receiving tank via sloshing and/or venting of the source tank. See at least paras 22, 27.
The Light reference additionally states (see para 6) that this procedure must be accomplished since pressure in the source tank increases upon receipt of gaseous H2 from the recipient tank; “If the vessel is already at the maximum operating pressure, then the additional GH 2 will need to be vented.”
Finally, per para 40, Light et al. teaches “connecting a liquid transfer conduit from the liquid cryogen storage tank to the liquid cryogen storage vessel… wherein, prior to said step of connecting a liquid transfer conduit, the liquid cryogen storage vessel has an initial pressure higher than an initial pressure of the liquid cryogen storage tank”. The Light reference additionally incorporates (see para 279) in its entirety U.S. Application 17/322,441, published as U.S. 2023/0160537 (Allideres et al).
In para 279, Light et al. additionally teaches “Those skilled in the art will recognize that the cryogen storage vessel or trailer of described in the instant Specification corresponds to the first tank of the ′441 Application and the cryogen storage vessel or final vessel described in the instant Specification corresponds to the second tank of the ′441 Application.”) and
- upon verification that the distribution condition is met, transferring a second quantity of cryogenic liquid from the first source tank to a second receiving tank, and simultaneously transferring of a second quantity of vaporization gas present in the second receiving tank to the first source tank (See at least paras 66 – 78, which detail the filling of first and second receiving tanks).
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Regarding Claim 2, Light et al. discloses the method according to Claim 1 above, wherein at least a fraction of the first quantity of vaporization gas is reliquefied in the first source tank and wherein the first quantity of cryogenic liquid comprises at least a first part of the reliquefied fraction of vaporization gas.
Specifically, the Light reference (see para 279) incorporates the teachings of “The device and/or method disclosed in U.S. patent application Ser. No. 17/322,441, filed May 17, 2021”, and later published as U.S. 2021/0364129 (Allideres et al.) Here (see Allideres, Fig. 4 and paras 55-56) gas from receiving tank 3 is depressurized “into the liquid phase” of source tank 2, and “allow vapors from the second tank 3 (via the first line 4) to be recovered into the liquid phase of the first tank 2 (and condense them).” These incorporated teachings of Allideres et al. read upon Claim 2 of the present application.
Regarding Claim 5, Light et al. discloses the method according to Claim 1 above, wherein the second quantity of cryogenic liquid comprises at least a second part of the reliquefied fraction of the first quantity of vaporization gas.
Please refer to the rejection of Claim 2 above, wherein Allideres et al. teaches reliquefication of the gas from second tank 3 into first tank 2. Light et al. additionally teaches (see the method steps at paras 66 to 78, with particular emphasis on steps g – l at paras 73-78) further filling of a second receiving tank, which would include using the gas recovered from the filling of the first receiving tank.
Regarding Claim 9, Light et al. discloses the method according to Claim 1, further comprising using a tractor vehicle to establish a fluid connection between the source tank and the receiving tank, and checking the distribution condition via at least one pressure and/or liquid level measuring device, installed on the source tank and/or on the tractor vehicle (see para 17).
Regarding Claim 10, Light et al. discloses the method according to Claim 9, wherein the tractor vehicle and/or the source tank or tanks comprise a pump configured to make it possible to pump the cryogenic liquid during the cryogenic liquid transfer step (the Light reference discloses the use of at least one pump at least at paras 78 and 157-163. The reference additionally states that "Conventional liquid hydrogen trailers typically have...(a) pressure builder" for delivery purposes. See para 17. See also para 203.).
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 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 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 7 is rejected under 35 U.S.C. 103 as being unpatentable over Light et al.
Regarding Claim 7, Light et al. discloses the method according to Claim 1 above, further comprising the additional steps of: transferring a third quantity of cryogenic liquid from a second source tank to the second receiving tank, and simultaneously transferring a third quantity of vaporization gas present in the second receiving tank to the second source tank, the third quantity of vaporization gas comprising at least an evaporated part of the second quantity of cryogenic liquid.
Please see the rejection of Claim 1 above, wherein Light et al. teaches transfer of a quantity of cryogenic liquid from a source tank (10) to a receiving tank (12), and simultaneously transferring a third quantity of vaporization gas present in the second receiving tank to the second source tank (paras 66-78), and Claim 2, wherein Light et al. (with the incorporation of Allideres et al.) teaches a quantity of vaporization gas comprising at least an evaporated part of the quantity of cryogenic liquid (Allideres, Fig. 4, and paras 55-56).
Although the cited references above mention a single source tank, the Light reference explicitly addresses the scenario wherein a single source tank/trailer fills multiple receiving tanks (see at least para 66). Additionally, the Light reference explicitly teaches the duplication of necessary components (see Light et al. para 310 and Examiner’s further rationale as presented in the rejection of Claim 1 above).
Given the scope of the teachings of the Light and incorporated Allideres references, it would have been obvious to one of ordinary skill in the art to simply duplicate the source tank/trailer of the above references to arrive at the “third quantity of cryogenic liquid from a second source tank”, the “third quantity of vaporization gas present in the second receiving tank”, and the “third quantity of vaporization gas comprising at least an evaporated part of the second quantity of cryogenic liquid”, as required in the present Claim 7. Here, the court has held that mere duplication of these components has no patentable significance unless a new and unexpected result is produced; an explanation of such is not mentioned in the present application. Please see MPEP 2144.
Claims 3-4, 6, and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Light et al., in view of Garner (US 2018/0128210).
Regarding Claim 3, Light et al. teaches the claimed method, to include a verification step, but does not explicitly recite said verification step as “further comprises checking the condition that the liquid level in the first source tank is higher than a predetermined liquid level threshold”, as claimed at Claim 3. Examiner notes that Light et al., however, does teach the monitoring of the receiving tank liquid level, and stopping flow when said receiving tank is full (see para 263).
However, Examiner asserts that one of ordinary skill in the art would know to perform, prior to commencing fueling, a verification of the liquid level in the source tank, if only to ensure that the source tank has the capability to actually provide fuel to a receiving tank. Examiner concludes that it would be obvious to one of ordinary skill to perform this verification step first prior to any other filling operation.
Regardless, and in the interests of compact prosecution, Examiner additionally relies on Garner, who teaches (see para 45 and Fig. 5, steps 500 and 510) “the controller determines if the liquid fuel level in tank 20 is above a predetermined level at step 510, for example a preferred threshold of liquefied fuel being greater than ⅔ full.” Garner’s method then teaches pressure level verification via “electrically controlled vapor valve 60.”
The combination of the Light and Garner references would therefore teach “the verification further comprises checking the condition that the liquid level in the first source tank is higher than a predetermined liquid level threshold, the distribution condition relating to the liquid level in the source tank preferably being checked before the distribution condition relating to the pressure in the first source tank”, as claimed in the present Claim 3.
The Light and Garner references each teach the hydrogen filling of a receiving tank. Additionally, the Garner reference explicitly teaches the basic step of verifying that the source tank is physically capable of filling the receiving tank. It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to insert the source tank liquid level verification step as taught by Garner into the verification procedure as disclosed by Light et al., in order to gain the advantages of ensuring that the source tank is physically capable of filling the receiving tank.
Regarding Claim 4, the combination of Light et al. and Garner above would therefore teach the method according to Claim 3, wherein, the liquid level in the source tank is higher than the predetermined liquid level threshold (as taught by Garner at para 45, and Fig. 5, steps 500 and 510) but the pressure in the source tank is not lower than the predetermined pressure threshold (as determined by the method of Light et al.; see Examiner’s comments and rationale in the rejection of Claim 1 above), the method comprises a step of depressurizing the source tank (via sloshing and/or venting, as taught by the Light reference; see the rejection of Claim 1 above) before the step of transferring the quantity of cryogenic liquid.
Regarding Claim 6, Light et al. teaches the claimed method, to include a step of depressurizing the source tank before the step of transferring the quantity of cryogenic liquid in response to determining that the pressure in the source tank is not lower than the predetermined pressure threshold, as claimed at Claim 6. Please see Examiner’s rationale as explained in the interpretation and rejection of Claim 1, wherein the Light reference (paras 22, 27, 40) teaches that it is known to slosh and/or vent the source tank if and when the pressure of said source tank rises above a pre-determined level. Again, one of ordinary skill in the art would know to do this for safety reasons.
Although the Light reference addresses source tank depressurization, the reference does not explicitly recite doing so “when the liquid level in the source tank is higher than the predetermined liquid level threshold”, as also claimed at Claim 6. Examiner notes that Light et al., however, does teach the monitoring of the receiving tank liquid level, and stopping flow when said receiving tank is full (see para 263).
However, Examiner asserts that one of ordinary skill in the art would know to perform, prior to commencing fueling, a verification of the liquid level in the source tank, if only to ensure that the source tank has the capability to actually provide fuel to a receiving tank. Examiner concludes that it would be obvious to one of ordinary skill to perform this verification step first prior to any other filling operation, to include the pressure verification method steps as taught by Light et al. at paras 22, 27, 40.
Garner teaches liquid level verification at para 45 and Fig. 5, steps 500 and 510: “the controller determines if the liquid fuel level in tank 20 is above a predetermined level at step 510, for example a preferred threshold of liquefied fuel being greater than ⅔ full.”
The Light and Garner references each teach the hydrogen filling of a receiving tank. Additionally, the Garner reference explicitly teaches the basic step of verifying that the source tank is physically capable of filling the receiving tank. It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to insert the source tank liquid level verification step as taught by Garner into the verification procedure as disclosed by Light et al., in order to gain the advantages of ensuring that the source tank is physically capable of filling the receiving tank.
Regarding Claim 8, Light et al. teaches the claimed method, to include a step of depressurizing the source tank before the step of transferring the quantity of cryogenic liquid in response to determining that the pressure in the source tank is not lower than the predetermined pressure threshold, as claimed at Claim 6. Please see Examiner’s rationale as explained in the interpretation and rejection of Claim 1, wherein the Light reference (paras 22, 27, 40) teaches that it is known to slosh and/or vent the source tank if and when the pressure of said source tank rises above a pre-determined level. Again, one of ordinary skill in the art would know to do this for safety reasons.
Although the Light reference addresses source tank depressurization, the reference does not explicitly recite doing so “when the liquid level in the source tank is higher than the predetermined liquid level threshold”, as also claimed at Claim 6. Examiner notes that Light et al., however, does teach the monitoring of the receiving tank liquid level, and stopping flow when said receiving tank is full (see para 263).
However, Examiner asserts that one of ordinary skill in the art would know to perform, prior to commencing fueling, a verification of the liquid level in the source tank, if only to ensure that the source tank has the capability to actually provide fuel to a receiving tank. Examiner concludes that it would be obvious to one of ordinary skill to perform this verification step first prior to any other filling operation, to include the pressure verification method steps as taught by Light et al. at paras 22, 27, 40.
Garner teaches liquid level verification at para 45 and Fig. 5, steps 500 and 510: “the controller determines if the liquid fuel level in tank 20 is above a predetermined level at step 510, for example a preferred threshold of liquefied fuel being greater than ⅔ full.”
The Light and Garner references each teach the hydrogen filling of a receiving tank. Additionally, the Garner reference explicitly teaches the basic step of verifying that the source tank is physically capable of filling the receiving tank. It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to insert the source tank liquid level verification step as taught by Garner into the verification procedure as disclosed by Light et al., in order to gain the advantages of ensuring that the source tank is physically capable of filling the receiving tank.
Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Light et al., in view of Minas (US 2023/0366513).
Regarding Claim 11, Light et al. teaches the claimed invention, to include a method of refueling multiple receiving tanks. However, the Light et al. reference does not explicitly recite said receiving tanks as being “aircraft cryogenic liquid fuel tanks”, not that “the method is implemented within the perimeter of an airport”, as claimed at Claim 11.
However, the refueling of hydrogen-powered aircraft is known, as evidenced by Minas, who teaches aircraft cryogenic liquid fuel tanks 206 for aircraft 204, serviced by refueler 202. See at least Fig. 2 and paras 2 and 35. Although the Minas reference does not use the word “airport”, the reference is explicitly drawn to the refueling of hydrogen powered aircraft; said refueling would occur at an airport, known to have a perimeter.
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The Light and Minas references each teach the hydrogen filling of receiving tanks. The Minas reference additionally teaches the explicit applicability to servicing hydrogen powered aircraft. It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to practice the teachings of Light et al. with specific applicability towards aircraft and airports, as taught by Minas, in order to gain the advantages of this applicability.
Claim 12 is rejected under 35 U.S.C. 103 as being unpatentable over Light et al., in view of:
- National Fire Protection Association (NFPA) -2, Hydrogen Technologies Code (2023 edition)
- California Fire Code 2022, section 2006.13 (retrieved at https://up.codes/viewer/california/ca-fire-code-2022/chapter/20/aviation-facilities#2006.13), and
- NFPA-407, Standards for Aircraft Fuel Service (2022 edition).
Regarding Claim 12, Light et al., as modified by Minas above teaches the method according to Claim 11, wherein the steps of transferring a first quantity of liquid, verifying, transferring a second quantity of liquid are executed, in series, in this order (Examiner interprets this previous verbiage as referring to the steps of antecedent Claim 1; please see the rejection of this claim above) and are preceded by the following preliminary steps:
- establishing a mechanical connection between the first source tank and the tractor vehicle, in a first zone of the airport intended for parking the source tanks and the tractor vehicle (Light et al., para 6, teaches “connecting a liquid transfer conduit from a liquid cryogen storage tank of a liquid cryogen tanker to a first liquid cryogen storage vessel installed at a first installation.” Minas additionally teaches “CcH2 refueler” 202 with onboard tank 220 at para 34 and/or an onboard LH2 supply tank at para 24, said refueler specifically designed to refuel aircraft per Fig. 2).
- moving, using the tractor vehicle, the first source tank and the tractor vehicle to a second zone of the airport (wherever the aircraft to be refueled are located, per the normal operation of the apparatus as taught by Minas), intended for filling the plurality of receiving tanks; and
- establishing a fluid connection between the first receiving tank (Minas, aircraft 204) and the first source tank (Minas, tank 220) via the tractor vehicle (Minas, 202), wherein the fluid connection between the first receiving tank and the first source tank via the refueling vehicle is interrupted (upon completion of the refueling process) before checking the at least one cryogenic liquid distribution condition (Light et al. teaches pressure control of the source tank as shown above in the rejection of Claim 1, see at least paras 6, 22, and 27. Minas additionally teaches automatic pressure checking and control after the initial refueling is completed; see paras 46-47).
Further regarding Claim 12, Light et al., as modified by Minas above, teaches the claimed invention, to include the hydrogen refueling of the receiving tanks of multiple aircraft with a source tank, and after refueling, controlling the pressure within said source tank in order to prevent over-pressurization of the source tank. As shown above in the rejections of antecedent Claims 1 and 11, Minas explicitly teaches doing so within the confines of an airport.
Neither reference explicitly teaches a method step of movement of an over-pressurized tank by a tractor vehicle to a first zone of an airport, wherein said first zone is “intended for parking the source tanks and the tractor vehicle” in order to perform the above pressure control operations (see Examiner’s interpretation above of the present Claim 12 phrase/limitation “…if the distribution condition is not respected, the first source tank and the tractor vehicle being moved to the first zone of the airport, at the using the tractor vehicle”).
However, Examiner asserts that it would have been obvious to one of ordinary skill in the art to move an over-pressurized tank away from an aircraft (which would normally be parked at an airport terminal, in the case of passenger aircraft, or near munitions, in the case of military aircraft) in order to mitigate the risks of catastrophic explosion, property damage, and/or loss of human life. Since pressure control of the over-pressurized tank would, as shown above, include venting hydrogen gas into the atmosphere, one of ordinary skill in the art would be highly motivated to perform such venting n an isolated area away from aircraft engines and other sources of ignition commonly associated with the aircraft and/or airport terminal.
Examiner additionally asserts that U.S. federal and state regulatory guidance, and international guidance concerning aircraft refueling and fire control at least suggest, if not outright mandate, the movement of over-pressurized tanks to an isolated area, and therefore make such movement a matter of common sense to one of ordinary skill in the art, as shown below:
- NFPA-2-2023 (Hydrogen Technologies Code, 2023 edition) states the following:
6.4.1.1.2 Pressure relief devices or stationary or portable containers shall be vented directly outdoors or to an exhaust hood.
6.10.1 Explosion control shall be provided where the quantity of GH2 or LH2 in storage or use exceeds the quantity thresholds requiring special provisions as listed in Table 6. 4.1 .1.1 or where otherwise required.
6.10.16.17.1 Exits of vent stacks shall be located outdoors and away from personnel areas, ignition sources, air intakes, building openings, and overhangs.
6.18.2.1.7. Ventilation Discharge. Ventilation discharge systems conveying hydrogen mixtures exceeding 25 percent LFL in any normal or emergency operating mode shall terminate at a point outdoors not less than 30 ft (9.1 m) from property lines, 10 ft (3 m) from operable openings into buildings and public access, 6 ft (1 .8 m) from exterior walls and roofs, 30 ft (9. 1 m) from combustible walls and operable openings into buildings that are in the direction of the exhaust discharge, and 1 0 ft (3 m) above adjoining grade. Examiner’s comment: although this paragraph does not apply directly to an aircraft, it does apply to an airport terminal gate, which is the normal refueling location for commercial and/or passenger aircraft.
7.1.16.2.1 Venting of GH2 shall be directed to an approved location.
- California Fire Code 2022, section 2006.13 states the following:
2006.13 Vehicle and Equipment Restrictions
During aircraft-fueling operations, only the equipment actively involved in the fueling operation is allowed within 50 feet (15 240 mm) of the aircraft being fueled. Other equipment shall be prohibited in this area until the fueling operation is complete.
A clear space of not less than 10 feet (3048 mm) shall be maintained between aircraft fuel-system vent openings and any part or portion of aircraft-servicing vehicles or equipment.
Examiner’s comment: one of ordinary skill in the art would recognize from this teaching that, upon completion of refueling, the equipment (e.g. first source tank and related tractor vehicle) would not be “actively involved” in fueling operations. Since a commercial airport typically hosts the simultaneous refueling of multiple aircraft, any over-pressurized tank (said tank could not be used to refuel for obvious safety reasons and therefore would not be “actively involved” in refueling operations) must be removed from the immediate vicinity of the serviced aircraft and its receiving tank.
2006.20 Aircraft Fuel-Servicing Vehicles Parking
Unattended aircraft fuel-servicing vehicles shall be parked in areas that provide for both the unencumbered dispersal of vehicles in the event of an emergency and the control of leakage such that adjacent buildings and storm drains are not contaminated by leaking fuel. Examiner’s comment: although this regulation applies to “unattended vehicles”, one of ordinary skill in the art would recognize the applicability to an over-pressurized tank as well, since such a scenario would constitute an “emergency” to be mitigated by the above procedure.
- NFPA-407 states the following:
6.2.1.1 Parking of Aircraft Fuel Servicing Tank Vehicles.
Parking areas for unattended aircraft fuel servicing tank vehicles shall be arranged to provide the following… (4) A minimum of 15 m (50 ft) from any parked aircraft and buildings other than maintenance facilities and garages for fuel servicing tank vehicles. Examiner’s comment: since this regulatory guidance is intended for (safe) unattended fuel servicing tanks, one of ordinary skill in the art would know to move an (unsafe) over-pressurized fuel servicing tank (i.e., the first source tank and related tractor vehicle of the present application) away from the aircraft as soon as practically possible.
In light of the above teachings, Examiner concludes:
- The Light and Minas references teach the hydrogen fueling of receiving tanks with the return of gaseous vapors into the source tank, and additionally teach the source tank would require pressure control for obvious safety reasons.
- The NFPA and California Fire Code teach movement of source tanks away from aircraft and populated areas for the purposes of pressure control, and to prevent catastrophic property damage and potential loss of human life due to the proximity of an over-pressurized and/or venting tank to an aircraft engine or other sources of ignition.
Therefore, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention supplement the refueling steps as disclosed by Light et al. and Minas with the additional steps required to return, move, and/or isolate the source hydrogen tank after completion of refueling operations, as taught or suggested by NFPA guidance and the California Fire Code, and as would be common sense to one of ordinary skill in the art. This would include accomplishing the Claim 12 limitation of “if the distribution condition is not respected, the first source tank and the tractor vehicle being moved to the first zone of the airport, at the using the tractor vehicle”, as interpreted by Examiner.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. US 2025/0102113 A1 teaches at least pressure monitoring and control associated with the hydrogen refueling of aircraft.
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/CHRISTOPHER M AFFUL/Primary Examiner, Art Unit 3753
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