Prosecution Insights
Last updated: April 19, 2026
Application No. 18/881,401

COMPRESSED GAS STORAGE TANK, SYSTEM AND METHOD

Non-Final OA §102§103§112
Filed
Jan 06, 2025
Examiner
CASTRIOTTA, JENNIFER
Art Unit
3733
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Ardent Underground Pty Ltd.
OA Round
1 (Non-Final)
62%
Grant Probability
Moderate
1-2
OA Rounds
2y 9m
To Grant
90%
With Interview

Examiner Intelligence

Grants 62% of resolved cases
62%
Career Allow Rate
424 granted / 687 resolved
-8.3% vs TC avg
Strong +29% interview lift
Without
With
+28.8%
Interview Lift
resolved cases with interview
Typical timeline
2y 9m
Avg Prosecution
41 currently pending
Career history
728
Total Applications
across all art units

Statute-Specific Performance

§101
0.2%
-39.8% vs TC avg
§103
40.0%
+0.0% vs TC avg
§102
26.6%
-13.4% vs TC avg
§112
28.7%
-11.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 687 resolved cases

Office Action

§102 §103 §112
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 . Notice From Examiner Applicant’s initial submission has 4 sets of claims. The claims examined below are the amended set of claims 1-22. Drawings The drawings are objected to because: The drawings are objected to as failing to comply with 37 CFR 1.84(p)(4) because reference character “218B” has been used to designate both a first fluid pipe and a second fluid pipe. The drawings are objected to as failing to comply with 37 CFR 1.84(p)(4) because reference character “218A” has been used to designate both a first fluid pipe and a second pipe. The drawings are objected to as failing to comply with 37 CFR 1.84(p)(5) because they do not include the following reference sign(s) mentioned in the description: 228. The drawings are objected to as failing to comply with 37 CFR 1.84(p)(5) because they include the following reference character(s) not mentioned in the description: 246, 70, 51, and 68. 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. Specification The disclosure is objected to because of the following informalities: The Specification references “Figure 1” multiple times. There is no “Figure 1”, but there are Figures 1A and 1B. Paragraph [0111] is supposed to be detailing what is shown in Figure 11, however what is discussed in the paragraph is actually what is shown in Figure 10. Appropriate correction is required. 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 3, 4, 7, 14, and 16-22 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 3 recites the limitation "the fluid" in line 2. There is insufficient antecedent basis for this limitation in the claim. For purposes of further examination, the claim is being interpreted as referencing “a fluid”. Claim 4 recites the limitation "the fluid" in line 2. There is insufficient antecedent basis for this limitation in the claim. For purposes of further examination, the claim is being interpreted as referencing “a fluid”. Claim 7 recites the limitation "the fluid" in line 3. There is insufficient antecedent basis for this limitation in the claim. For purposes of further examination, the claim is being interpreted as referencing “a fluid”. Claim 14 recites the limitation "the fluid" in line 2. There is insufficient antecedent basis for this limitation in the claim. For purposes of further examination, the claim is being interpreted as referencing “a fluid”. Further, claim 14 referencing what type of fluid there is appears to be completely out of context as claim 14 depends from claim 1 which does not discuss a fluid. Does the Applicant intend for claim 14 to depend from claim 3, 4, or 7 which precede claim 14, but reference the fluid? Further clarification is required. Claim 14 currently states “A gas storage tank according to claim 1…” However, claims 1 is drawn to “A storage tank” and claim 2-13 are also drawn to “A storage tank”. It’s unclear if this is intended to be an indication of a change in preamble or if it is simply a typo. For purposes of further examination, the claim is being interpreted as stating “A [[gas]] storage tank according to claim 1…” Further clarification and/or correction is required. Claim 16 recites the limitation "the fluid" in the last line. There is insufficient antecedent basis for this limitation in the claim. For purposes of further examination, the claim is being interpreted as referencing “a fluid”. 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 (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 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) 1, 3-5, 11, 12, 14, and 15 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Mouwen (EP 2832666) (cited by Applicant). Regarding Claim 1 Mouwen teaches a storage tank (below – Fig. 5) arranged within a surrounding structure (11), the storage tank comprising: a first chamber (shown at 10) configured to store a first gas under pressure, the first chamber being defined by a first wall (13) and having a substantially fixed volume; a flexible membrane (32) provided between the first wall and the surrounding structure; a second chamber (31) between the first wall and the flexible membrane, wherein the second chamber has a variable volume; and at least one transfer pipe (22) which supplies the first gas into the first chamber, wherein the second chamber surrounds the first chamber such that the first wall is between the first chamber and the second chamber (Paragraphs [0023] and [0034]) . PNG media_image1.png 835 368 media_image1.png Greyscale Regarding Claim 3 Mouwen teaches a pressure of a fluid in the second chamber (32) is regulated to correspond to a pressure of the first gas in the first chamber (shown at 10). Regarding Claim 4 Mouwen teaches a regulator is associated with the storage tank and a pressure of a fluid in the second chamber (32) is regulated by the regulator to correspond to a pressure of the first gas in the first chamber (shown at 10) such that forces acting on the first wall (13) by the first gas in the first chamber are opposed by forces acting on the first wall by the fluid in the second chamber. Regarding Claim 5 Mouwen teaches the first gas is drawable from the first chamber (shown at 10) via the at least one transfer pipe (22). Regarding Claim 11 Mouwen teaches when the second chamber (32) is pressurised above a threshold value, the volume of the second chamber will increase and decrease to compensate for movement in the surrounding structure (11). Regarding Claim 12 Mouwen teaches the second chamber (32) is configured to hold a fluid which is different to the first gas. Regarding Claim 14 Mouwen teaches a fluid water. Regarding Claim 15 Mouwen teaches the flexible membrane (31) is made from a reinforced plastics material. Claim(s) 1, 8, and 12-15 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Hyde et al. (US 9470367) (hereinafter Hyde). Regarding Claim 1 Hyde teaches a storage tank (below – Fig. 3 and 4) arranged within a surrounding structure(40/42), the storage tank comprising: a first chamber configured to store a first gas (30) under pressure, the first chamber being defined by a first wall (34) and having a substantially fixed volume; a flexible membrane (36) provided between the first wall (34) and the surrounding structure (40/42); a second chamber (shown at 36) between the first wall and the flexible membrane, wherein the second chamber has a variable volume; and at least one transfer pipe (not shown) which supplies the first gas into the first chamber, wherein the second chamber surrounds the first chamber such that the first wall is between the first chamber and the second chamber, as can be seen in the figures below (Col. 3, Ln. 35-45, Col. 4, Ln. 43-55, Col. 5, Ln. 23-25, Col. 6, Ln. 65-67, and Col. 7, Ln. 26-29). PNG media_image2.png 320 412 media_image2.png Greyscale PNG media_image3.png 168 237 media_image3.png Greyscale Regarding Claim 8 Hyde teaches the first wall (34) comprises steel (Col. 4, Ln. 51-55). Regarding Claim 12 Hyde teaches the second chamber is configured to hold a fluid (e.g. water) which is different to the first gas (e.g. natural gas). Regarding Claim 13 Hyde teaches the first gas is natural gas. Regarding Claim 15 Hyde teaches the flexible membrane is made from a polymers (e.g. rubber, a plastics material, or urethane) (Col. 5, Ln. 23-25). 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) 2, 6, 13, and 16-19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Mouwen as applied to claim 1 above. Regarding Claims 2 and 13 Mouwen teaches all the limitations of claim 1 as shown above. Mouwen further teaches that the first chamber (shown at 10) stores a compressed gas. However, Mouwen does not specifically teach the compressed gas is hydrogen, or selected from the group consisting of nitrogen, carbon dioxide, natural gas, hydrocarbon gases, and oxygen. Given that hydrogen, nitrogen, carbon dioxide, natural gas, hydrocarbon gases, and oxygen are all well-known compressed gasses stored in storage tanks, at the time of filing, it would have been an obvious matter of design choice to a person of ordinary skill in the art that the compressed gas stored in the storage tank of Mouwen could be hydrogen, nitrogen, carbon dioxide, natural gas, hydrocarbon gases, or oxygen. As such, the claim of the first gas being hydrogen, or selected from the group consisting of nitrogen, carbon dioxide, natural gas, hydrocarbon gases, and oxygen does not provide patentable distinction over the prior art of record. See MPEP 2143(I)(E). Regarding Claim 6 Mouwen teaches all the limitations of claim 1 as shown above. Mouwen further teaches that the second chamber (32) is filled with a fluid and pressure controlled so that the volume is able to be adjusted (Paragraph [0032]). However, Mouwen does not specifically teach at least one fluid pipe through which the fluid is supplied into the second chamber and through which the fluid is drawn from the second chamber. Based on the fact that Mouwen has the second chamber including a pressure controlled variable volume with a fluid inside it, it would appear obvious to one of ordinary skill in the art that Mouwen would include at least one fluid pipe through which the fluid is supplied into the second chamber and through which the fluid is drawn from the second chamber, in order to maintain the desired pressure. See MPEP 2143(I)(C). Regarding Claim 16 Mouwen teaches all the limitations of claim 1 as shown above. Mouwen further teaches a first delivery system (22) configured to supply the first gas to the first chamber; and the second chamber is filled with a fluid and pressure controlled so that the volume is able to be adjusted (Paragraph [0032]). However, Mouwen does not specifically teach a second delivery system configured to supply a fluid to the second chamber. Based on the fact that Mouwen has the second chamber including a pressure controlled variable volume with a fluid inside it, it would appear obvious to one of ordinary skill in the art that Mouwen would include a second delivery system configured to supply a fluid to the second chamber, in order to maintain the desired pressure. See MPEP 2143(I)(C). Regarding Claim 17 Modified Mouwen teaches all the limitations of claim 16 as shown above. Mouwen further teaches a regulator which regulates a pressure of the fluid in the second chamber (32) to correspond to a pressure of the first gas in the first chamber (shown at 10). Regarding Claim 18 Modified Mouwen teaches all the limitations of claim 16 as shown above. Mouwen further teaches a regulator which regulates a pressure of the fluid in the second chamber (32) to correspond to a pressure of the first gas in the first chamber (shown at 10) such that forces acting on the first wall (13) by the first gas in the first chamber are opposed by forces acting on the first wall by the fluid in the second chamber. Regarding Claim 19 Modified Mouwen teaches all the limitations of claim 16 as shown above. Mouwen further teaches the pressure in the second chamber (32) is regulated to be substantially equal to the pressure in the first chamber (shown at 10). Claim(s) 22 is/are rejected under 35 U.S.C. 103 as being unpatentable over modified Mouwen as applied to claim 16 above, and further in view of Joubert Des Ouches et al. (US 11346499) (hereinafter Joubert Des Ouches). Regarding Claim 22 Modified Mouwen teaches all the limitations of claim 16 as shown above. Modified Mouwen does not teach sensors for detecting a presence of the first gas within the fluid. Joubert Des Ouches teaches a storage tank (below – Fig. 1A) having a first chamber (100) configured to store a first gas under pressure, the first chamber being defined by a first wall and having a substantially fixed volume; and sensors for detecting a leak of gas from within the first chamber (Col. 3, Ln. 48-53). PNG media_image4.png 253 457 media_image4.png Greyscale Modified Mouwen and Joubert Des Ouches are analogous inventions in the field of storage tanks for gas under pressure. It would have been obvious to one skilled in the art at the time of filing to modify the storage tank of modified Mouwen with the teachings of a sensor to detect a leak from the first chamber (and thus the presence of the first gas within the fluid) in order to alert the user to a leak within the first chamber. Claim(s) 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Hyde as applied to claim 8 above. Regarding Claim 8 Hyde teaches all the limitations of claim 8 as shown above. Hyde does not specifically teach first wall comprises a reinforced concrete. However, Hyde teaches the first wall is formed as a gas and/or liquid-impermeable layer (Col. 4, Ln. 61-63). Hyde further teaches that reinforced concrete is a material that is known for containing liquid and vapors (Col. 6, Ln. 1-9). Because Hyde teaches that both steel and reinforced concrete are layer materials known for their barrier properties regarding liquid and gasses, it would have been an obvious to a person of ordinary skill in the art at the time of filing to utilize reinforced concrete (which is known to be reinforced using steel) as the material for the first wall to achieve the predictable result of a container wall that creates a liquid and gas barrier between the first and second chambers. See MPEP 2143(I)(B). Allowable Subject Matter Claims 7, 20, and 21 would be allowable if rewritten to overcome the rejection(s) under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), 2nd paragraph, set forth in this Office action and to include all of the limitations of the base claim and any intervening claims. Claim 10 is objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. The following is a statement of reasons for the indication of allowable subject matter: Regarding Claim 7: Closest prior art – Mouwen (cited above) – teaches a majority of the Applicant’s invention. However, Mouwen does not teach at least one first pipe in communication with the second chamber and at least one second pipe in communication with the second chamber, wherein a fluid is supplied to the second chamber via the at least one first pipe or the at least one second pipe and the fluid returns from the second chamber via the other of the at least one first pipe and the at least one second pipe. Regarding Claim 10: Closest prior art – Hyde (cited above) – teaches a majority of the Applicant’s invention. However, Hyde does not teach the first wall comprises an internal steel liner and an external steel shell and a reinforced concrete layer between the internal steel liner and the external steel shell. Regarding Claim 20: Closest prior art – Mouwen (cited above) – teaches a majority of the Applicant’s invention. However, Mouwen does not teach a circulation system to circulate the fluid within the second chamber in order to regulate a temperature of the second chamber. Regarding Claim 21: Closest prior art – Mouwen (cited above) – teaches a majority of the Applicant’s invention. However, Mouwen does not teach the storage tank comprises at least one first pipe in communication with the second chamber and at least one second pipe in communication with the second chamber, the fluid is supplied to the second chamber via the at least one first pipe or the at least one second pipe and the fluid returns from the second chamber via the other of the at least one first pipe and the at least one second pipe, and the second delivery system is connected to the at least one first pipe and the at least one second pipe. Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Further pertinent prior art includes but is not limited to that which is listed in the attached Notice of References Cited. Any inquiry concerning this communication or earlier communications from the examiner should be directed to JENNIFER CASTRIOTTA whose telephone number is (571)270-5279. The examiner can normally be reached Monday - Friday 9am-5pm. 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, Nathan Jenness can be reached at (571) 270-5055. 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. /JENNIFER CASTRIOTTA/Examiner, Art Unit 3733 /DON M ANDERSON/Primary Examiner, Art Unit 3733
Read full office action

Prosecution Timeline

Jan 06, 2025
Application Filed
Jan 08, 2026
Non-Final Rejection — §102, §103, §112 (current)

Precedent Cases

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
62%
Grant Probability
90%
With Interview (+28.8%)
2y 9m
Median Time to Grant
Low
PTA Risk
Based on 687 resolved cases by this examiner. Grant probability derived from career allow rate.

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