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 .
Election/Restrictions
Applicant’s election with traverse of invention I and species A1 (encompassing claims 1-10) in the reply filed on 04/02/2026 is acknowledged. Claims 11-20 are withdrawn from further consideration pursuant to 37 CFR 1.142(b), as being drawn to a nonelected invention and species, there being no allowable generic or linking claim. Applicant timely traversed the restriction (election) requirement in the reply filed on 04/02/2026. The traversal is on the ground(s) that Applicant alleges that a serious search and examination burden is not required for a proper restriction requirement. (M.P.E.P. § 803). In the present case, each of the claims of Groups I and II are directed to liquid gas storage containers comprising an inner shell forming a cavity, an outer shell forming an insulation volume between the inner shell and the outer shell, and a first insulation layer formed of a closed-cell insulation material that is disposed within the insulation volume. This is not found persuasive. Contrary to Applicant's assertion the inventions have acquired a separate status in the art in view of their different classification and because of storage container with distinct wall structures, which require a different field of search, for example, searching different classes/subclasses the prior art applicable to one invention would not likely be applicable to another invention. Therefore, the requirement is still deemed proper and is made final.
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 1-10 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 1 recites the limitation “the first insulation layer formed of a closed-cell insulation material” renders the claim indefinite because it is unclear what kind of material constitute a “closed-cell insulation material”.
Claim 2 recites the limitation wherein “the inner shell comprises a cryogenic metal” renders the claim indefinite because it is unclear if it meant that the inner shell is of metal, or inside volume occupied by the inner shell comprises cryogenic metal. Furthermore, it is unclear what the phrase “cryogenic metal” means.
Claims 4 and 5 recite “greater than 50% nitrogen” and “greater than 50% argon” respectively without specifying the measurement basis — volume, weight, molar fraction, or partial pressure. The specification at ¶ [0036] expressly qualifies these figures “when measured by partial pressures,” but this qualifier is absent from both claims, rendering their scope indefinite.
Claim 10 recites “about 60 wt% to about 99 wt% perlite and about 1 wt% to about 40 wt% glass microspheres.” The term “about” applied to both endpoints of both ranges renders the numerical boundaries indefinite, as the specification nowhere defines the permissible deviation from these values. See Nautilus, 572 U.S. at 901.
Claims 3 and 6-9 are also rejected under 35 U.S.C. 112(b) for 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.
Claim(s) 1-10 are rejected under 35 U.S.C. 103 as being unpatentable over Cimadevilla Garcia et al. (US 2023/0375139 A1) in view of Allen et al. (US 2003/0203149 A1).
In regard to claim 1, Cimadevilla discloses a liquid gas storage container (¶ 0025, Abstract) comprising:
an inner shell (18) forming a cavity (inside of 18 containing H2) (fig. 2; ¶ 0039);
an outer shell (12) forming an insulation volume between the inner shell (18) and the outer shell (12) (see fig. 2; ¶ 0039);
a first insulation layer (13) disposed within the insulation volume and around the inner shell (18); and
a second insulation layer (14) disposed within the insulation volume between the first insulation layer (13) and the outer shell (12) (fig. 2);
Cimadevilla does not teach the first insulation layer (13) formed of a closed-cell insulation material. Cimadevilla’s inner layer (13) is open-cell material (¶ 0042).
However, Allen teaches closed-cell foam sheet as the material used between the vessel wall and the inner surface of the microsphere insulation system (Allen, ¶ 0058). Cimadevilla does not teach a second insulation layer of bulk fill material disposed between the first insulation layer and the outer shell (even though its not claimed in claim 1). Cimadevilla’s outer layer (14) is closed-cell foam, not bulk fill (¶ 0042). Allen teaches microsphere particles poured into the annular space of a cryogenic LH₂ storage vessel as bulk fill insulation (Allen, ¶ 0034, 0040; FIG. 4 element 70; FIG. 6). Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filling date of the claimed invention, to modify the storage container of Cimadevilla by replacing Cimadevilla’s open-cell inner layer (13) with Allen’s closed-cell foam and replace Cimadevilla’s outer closed-cell layer (14) with Allen’s microsphere bulk fill, in order to maximize moisture resistance, structural rigidity, and insulation value, because replacing an open-cell inner layer with closed-cell foam provides a superior vapor barrier to prevent mold, while replacing the outer closed-cell layer with microsphere bulk fill offers superior durability, extreme thermal efficiency, and lighter weight. Both substitutions use known materials for the same purpose in the same application with predictable results. KSR, 550 U.S. at 417.
In regard to claim 2, the modified Cimadevilla does not expressly teach the inner shell comprising a cryogenic metal. Allen teaches stainless steel as the material used in the fabrication of cryogenic tanks and transfer lines, the inner shell comprises a cryogenic metal (Allen, ¶ 0028).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to fabricate the inner shell of the modified Cimadevilla tank from a cryogenic metal such as stainless steel or aluminum alloy, in order to ensure structural integrity and material compatibility at liquid hydrogen service temperatures of approximately 20K, because metals such as austenitic stainless steel and aluminum alloy are the well-established and recognized materials of construction for inner vessels in cryogenic hydrogen service, as confirmed by Allen (¶ 0028).
In regard to claim 3, the modified Cimadevilla discloses the liquid gas storage container of claim 2, but does not explicitly teach the cavity comprises a volume of greater than about 3,000 m³, as Cimadevilla is directed primarily at aviation applications where compact size is a design priority (¶ 0010–0013). Allen expressly teaches that microsphere insulation is particularly advantageous for large cryogenic storage dewars and targets large-scale liquid hydrogen storage vessels (Allen, ¶ 0038; ¶ 0040; FIG. 6). Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to scale the two-layer insulation architecture of the modified Cimadevilla tank to a cavity volume exceeding 3,000 m³, in order to meet the well-recognized industrial demand for large-scale ground-based LH₂ storage. Allen expressly identifies large-scale LH₂ storage as the primary commercial application for this class of insulation system (¶ 0038, 0040). The present application’s own background further confirms large-scale LH₂ storage exceeding 3,000 m³ as a recognized and urgent industrial need (¶ 0009–0011).
In regard to claim 4, the modified Cimadevilla discloses the liquid gas storage container of claim 1, wherein Cimadevilla does not explicitly teach filling the first insulation layer with a gas comprising greater than 50% nitrogen. Cimadevilla identifies N₂ as one of several low-conductivity gas options for its outer closed-cell foam layer (14) only (¶ 0042). Allen teaches nitrogen as a preferred backfill gas that increases insulation value in cryogenic insulation forms (Allen, ¶ 0008).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to fill the closed-cell foam first insulation layer of the modified Cimadevilla tank with a gas comprising greater than 50% nitrogen, in view of the teachings of Allen, in order to minimize thermal conductivity within the foam cells and improve overall insulation performance, because both Cimadevilla and Allen independently identify nitrogen as a preferred low-conductivity gas for use in closed-cell foam insulation in cryogenic LH₂ applications, and selecting nitrogen as the dominant fill gas at greater than 50% follows directly from both references’ endorsement of nitrogen for this purpose. No inventive step is required to specify a majority nitrogen fill in a layer where nitrogen is the recognized preferred gas, and the result is entirely predictable.
In regard to claim 5, the modified Cimadevilla discloses the liquid gas storage container of claim 1, wherein Cimadevilla does not explicitly teach the second insulation layer comprises a second gas, wherein the second gas comprises greater than 50% argon.
Allen teaches argon as a preferred backfill gas for cryogenic insulation forms alongside nitrogen, teaching that backfilling increases insulation value compared to ambient air (Allen, ¶ 0008).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to fill the bulk fill second insulation layer of the modified Cimadevilla tank with a gas comprising greater than 50% argon, in view of the teachings of Allen, in order to increase the insulation value of the outer annular space beyond what is achievable with ambient air, because Allen expressly teaches argon and nitrogen as equally preferred backfill gas options for cryogenic insulation forms and confirms that either gas increases insulation value compared to ambient (¶ 0008). Selecting argon rather than nitrogen for the outer bulk fill layer is a routine engineering choice among a finite and well-characterized set of inert low-conductivity fill gases, each with known thermal performance, and no unexpected results would arise from this selection.
In regard to claim 6, the modified Cimadevilla discloses the liquid gas storage container of claim 1, wherein Cimadevilla does not explicitly teach the closed-cell insulation material comprises a closed-cell foam. Cimadevilla’s inner layer (13) is open-cell material (¶ 0042). Allen expressly teaches closed-cell foam sheet as the preferred material for the inner insulation layer directly adjacent to the vessel wall in a cryogenic microsphere insulation system (Allen, ¶ 0058).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to use closed-cell foam as the first insulation layer disposed around the inner shell in the modified Cimadevilla tank, in view of the teachings of Allen, in order to provide a dimensionally stable, gas-impermeable insulation barrier directly at the cryogenic vessel surface, because Allen specifically teaches that closed-cell foam sheet is an effective and easy to install material for use in the inner layer position adjacent to the cryogenic vessel wall in combination with a microsphere bulk fill outer layer (¶ 0058), and Cimadevilla itself confirms that closed-cell foam is an appropriate insulation material for use in an LH₂ inter-tank space by employing it in its own outer insulation layer (14) (¶ 0042). One of ordinary skill in the art combining these two references would have recognized that closed-cell foam’s gas impermeability is particularly valuable at the inner layer position where it directly contacts the cryogenic vessel surface.
In regard to claim 7, the modified Cimadevilla discloses the liquid gas storage container of claim 6, wherein Cimadevilla does not explicitly teach the second insulation layer comprises a bulk fill material. Cimadevilla’s outer layer (14) is closed-cell foam, not a poured bulk fill material (¶ 0042). Allen teaches microsphere particles and perlite poured into the annular space of a cryogenic LH₂ storage vessel as bulk fill insulation (Allen, ¶ 0034, 0040; FIG. 4 element 70; ¶ 0027).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to replace the outer closed-cell foam layer (14) of Cimadevilla with a bulk fill insulation material in the same annular space position, in view of the teachings of Allen, in order to improve insulation uniformity and thermal efficiency in the outer inter-tank space, particularly at large vessel scale, because Allen teaches that pouring microsphere or perlite bulk fill into the annular space between the inner vessel and outer jacket provides superior packing uniformity and thermal performance compared to rigid foam panels, and is particularly advantageous for large LH₂ storage vessels where rigid foam installation at scale is impractical (¶ 0038, 0040). The substitution places a known material in a known structural position with predictable results.
In regard to claim 8, the modified Cimadevilla discloses the liquid gas storage container of claim 7, wherein Cimadevilla does not explicitly teach the bulk fill material comprises one or more of perlite, glass microspheres, or silica aerogel, or mixtures thereof.
Allen expressly teaches all three as known and characterized bulk fill materials for the same cryogenic vessel annular space application (Allen, ¶ 0004, 0027-perlite; ¶ 0029, 0034- glass microspheres; ¶ 0012- aerogels and silica).
– the bulk fill material comprises one or more of perlite, glass microspheres, or silica aerogel, or mixtures thereof (Allen, ¶ 0004, 0027 - perlite; ¶ 0029, 0034-glass microspheres; ¶ 0012 - aerogels and silica).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to select perlite, glass microspheres, silica aerogel, or a combination thereof as the bulk fill material for the second insulation layer of the modified Cimadevilla tank, in view of the teachings of Allen, in order to achieve low thermal conductivity and effective insulation performance in the outer annular space of the LH₂ storage vessel, because Allen identifies these three materials as the recognized and established options for cryogenic vessel annular space bulk fill insulation, each with well-documented thermal properties (¶ 0004, 0027, 0029, 0034; ¶ 0012). Selecting any one or a combination of these materials for the same purpose in the same application involves no more than routine engineering selection from a finite set of known options with predictable results.
In regard to claim 9, the modified Cimadevilla discloses the liquid gas storage container of claim 8, wherein Cimadevilla does not explicitly teach the second insulation layer comprises a mixture of perlite and glass microspheres.
Allen teaches both as alternative bulk fill materials for the same cryogenic vessel annular space and places them in direct side-by-side performance comparison (Allen, ¶ 0004, 0027; ¶ 0029, 0034; FIG. 6A vs. FIG. 6B).
– the second insulation layer comprises a mixture of perlite and glass microspheres (Allen, ¶ 0004, 0027 - perlite; ¶ 0029, 0034-glass microspheres; FIG. 6A vs. FIG. 6B -direct comparison)
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to use a mixture of perlite and glass microspheres as the bulk fill material for the second insulation layer of the modified Cimadevilla tank, in view of the teachings of Allen, in order to achieve an intermediate flow permeability and thermal conductivity between that of perlite alone and glass microspheres alone, because Allen presents perlite and glass microspheres as competing alternatives for the same annular space bulk fill application and directly compares their performance side by side (FIG. 6A vs. FIG. 6B), thereby motivating a POSITA to explore blends of the two materials as a straightforward means of tuning insulation performance between the two known endpoints. Blending two known granular bulk fill materials to achieve intermediate performance characteristics is a routine engineering approach that requires no inventive step and yields a predictable result.
In regard to claim 10, the modified Cimadevilla discloses the liquid gas storage container of claim 9, wherein Cimadevilla does not explicitly teach the mixture comprises about 60 wt% to about 99 wt% perlite and about 1 wt% to about 40 wt% glass microspheres.
Allen establishes perlite as the conventional baseline and identifies glass microspheres as the improved alternative, while providing well-characterized physical property data for glass microspheres including bulk density of 0.064 g/cc and crush strength of 1.7 MPa (Allen, ¶ 0029; ¶ 0027, 0038; FIG. 6A vs. FIG. 6B).
– the mixture comprises about 60 wt% to about 99 wt% perlite and about 1 wt% to about 40 wt% glass microspheres (Allen, ¶ 0029; ¶ 0027, 0038; FIG. 6A vs. FIG. 6B)
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to use a mixture comprising about 60–99 wt% perlite and about 1–40 wt% glass microspheres as the bulk fill material for the second insulation layer of the modified Cimadevilla tank, in view of the teachings of Allen, in order to optimize flow permeability and thermal insulation performance of the outer annular space, because Allen establishes perlite as the conventional all-perlite baseline (¶ 0027) and glass microspheres as an improved alternative with fully characterized physical properties (¶ 0029), and the FIG. 6A vs. FIG. 6B comparison directly motivates progressive substitution of microspheres into a perlite-dominated baseline to incrementally improve performance toward the all-microsphere result. The claimed weight range- a perlite-dominated mixture with a minor to moderate microsphere fraction - describes exactly the routine optimization range that a POSITA would explore starting from Allen’s perlite baseline and incrementally substituting microspheres.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to WEBESHET MENGESHA whose telephone number is (571)270-1793. The examiner can normally be reached Mon-Thurs 7-4, alternate Fridays, EST. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Frantz Jules can be reached at 571-272-6681. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/W.M/Examiner, Art Unit 3763
/FRANTZ F JULES/Supervisory Patent Examiner, Art Unit 3763
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