Prosecution Insights
Last updated: April 19, 2026
Application No. 19/081,414

HEAT ENGINE

Non-Final OA §DP
Filed
Mar 17, 2025
Examiner
NGUYEN, HOANG M
Art Unit
3746
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Technion Research & Development Foundation Limited
OA Round
1 (Non-Final)
76%
Grant Probability
Favorable
1-2
OA Rounds
2y 7m
To Grant
92%
With Interview

Examiner Intelligence

Grants 76% — above average
76%
Career Allow Rate
1292 granted / 1708 resolved
+5.6% vs TC avg
Strong +16% interview lift
Without
With
+16.4%
Interview Lift
resolved cases with interview
Typical timeline
2y 7m
Avg Prosecution
25 currently pending
Career history
1733
Total Applications
across all art units

Statute-Specific Performance

§101
0.6%
-39.4% vs TC avg
§103
57.5%
+17.5% vs TC avg
§102
10.0%
-30.0% vs TC avg
§112
8.6%
-31.4% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1708 resolved cases

Office Action

§DP
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 . Obviousness Double Patenting rejection Claims 1-10 are rejected on the ground of nonstatutory double patenting as being unpatentable over claim 5 of U.S. Patent No. 12,281,601 or claim 5 of US patent 11,927,117. Although the claims at issue are not identical, they are not patentably distinct from each other because of the following reasons. Claim-matching table: Claims 1, 5, 9, 10, of this application Claim 5 of US 12,281,601 Claim 5 of US 11,927,117 1. Apparatus for producing mechanical work comprising: a heat engine comprising: a heat transfer liquid (HTL) input port for accepting HTL into the heat engine; a gas injector port for injecting compressed gas into the heat engine; one or more chambers for mixing the gas and the HTL, producing a gas-and-HTL mixture; and a plurality of nozzles for receiving said gas-and-HTL mixture and allowing said gas-and-HTL mixture to undergo isothermal or quasi-isothermal expansion therein, resulting in ejecting the gas-and-HTF mixture; and a rotor; wherein the ejection of the gas-and-HTF mixture through the one or more nozzle(s) results in the rotation of the rotor, thereby producing mechanical work. 5. The apparatus according to claim 1 wherein the heat engine is designed to withstand HTL comprising molten salt. 9. The apparatus of claim 1, wherein the HTL comprises a liquid selected from a group consisting of: water, oil, molten salt, and molten metal. 10. The apparatus of claim 1, wherein the plurality of nozzles is mounted on a turbine that comprises said rotor to result in its rotation. 5. A method for converting heat to mechanical work comprising: providing incoming heat transfer fluid (HTL) at a first temperature to a plurality of mixing chambers; providing incoming compressed gas at a second temperature to the plurality of mixing chamber; enabling the gas and the HTL to mix, producing a gas-and-HTL mix; enabling the HTL in the gas-and-HTL mix to heat the gas and isothermal expansion of the gas in the gas-and-HTL mix; limiting volume of the gas-and-HTL mix, thereby increasing pressure of the gas and causing acceleration of a flow of the gas-and-HTL mix; causing the gas-and-HTL mix to eject through a plurality of nozzles, thereby converting the heat of the HTL to kinetic energy to cause movement of the plurality of nozzles, wherein the plurality of nozzles is mounted on a turbine to result in its rotation; and using the kinetic energy to produce mechanical work. 5. A method for converting heat to mechanical work comprising: providing incoming heat transfer fluid (HTF) at a first temperature to a plurality of mixing chambers; providing incoming compressed gas at a second temperature to the plurality of mixing chamber; enabling the gas and the HTF to mix, producing a gas-and-HTF mix; enabling the HTF in the gas-and-HTF mix to heat the gas and isothermal expansion of the gas in the gas-and-HTF mix; limiting volume of the gas-and-HTF mix, thereby increasing pressure of the gas and causing acceleration of a flow of the gas-and-HTF mix; causing the gas-and-HTF mix to eject through a plurality of nozzles, thereby converting the heat of the HTF to kinetic energy to cause movement of the plurality of nozzles, wherein the plurality of nozzles is mounted on a turbine to result in its rotation; and using the kinetic energy to produce mechanical work; wherein the HTF comprises a fluid selected from a group consisting of: water, oil, molten salt and molten metal. Obviousness: From the claim-matching table above, the method claim 5 of US 11,927,117 recites all the operating steps equivalent with the functions of the claimed elements in the apparatus claims 1, 5, 9, 10 of this application but in method form instead of apparatus form as in this application. However, according to MPEP 2144.05, II. ROUTINE OPTIMIZATION, A) Optimization Within Prior Art Conditions or Through Routine Experimentation, In re Williams, 36 F.2d 436, 438 (CCPA 1929) ("It is a settled principle of law that a mere carrying forward of an original patented conception involving only change of form, proportions, or degree, or the substitution of equivalents doing the same thing as the original invention, by substantially the same means, is not such an invention as will sustain a patent, even though the changes of the kind may produce better results than prior inventions."). See also KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 416 (2007) (identifying "the need for caution in granting a patent based on the combination of elements found in the prior art."). It would have been a “routine optimization” for a person having ordinary skill in the art to form an apparatus in the claims of this application based on the equivalent operating steps in claim 5 of US 11,927,117 for the purpose of forming an apparatus to perform works. Regarding dependent claims 2, 3, 4, 6-8, claim 5 of US 11,927,117 does not teach different number of heat engines in claim 2, different types of rotor in claim 3, different temperature/pressure to prevent cavitation in claims 4, 6-8. However, again according to MPEP 2144.05, II. ROUTINE OPTIMIZATION, it would have been obvious and as a matter of “routine optimization” to elect different number of heat engines in claim 2, different types of rotor in claim 3, different temperature/pressure to prevent cavitation in claims 4, 6-8 in the apparatus formed by the method steps of claim 5 of US, 11,927,117 for the purpose of generating appropriate work output. Also from the claim-matching table above, the method claim 5 of US 12,281,601 recites all the operating steps equivalent with the functions of the claimed elements in the apparatus claims 1, 10 of this application but in method form instead of apparatus form as in this application. However, according to MPEP 2144.05, II. ROUTINE OPTIMIZATION, A) Optimization Within Prior Art Conditions or Through Routine Experimentation, In re Williams, 36 F.2d 436, 438 (CCPA 1929) ("It is a settled principle of law that a mere carrying forward of an original patented conception involving only change of form, proportions, or degree, or the substitution of equivalents doing the same thing as the original invention, by substantially the same means, is not such an invention as will sustain a patent, even though the changes of the kind may produce better results than prior inventions."). See also KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 416 (2007) (identifying "the need for caution in granting a patent based on the combination of elements found in the prior art."). It would have been a “routine optimization” for a person having ordinary skill in the art to form an apparatus in the claims of this application based on the equivalent operating steps in claim 5 of US 12,281,601 for the purpose of forming an apparatus to perform works. Regarding dependent claims 2-9, claim 5 of US 12,281,601 does not teach different number of heat engines in claim 2, different types of rotor in claim 3, different temperature/pressure to prevent cavitation in claims 4, 6-8, different fluids in claims 5, 9. However, again according to MPEP 2144.05, II. ROUTINE OPTIMIZATION, it would have been obvious and as a matter of “routine optimization” to elect different number of heat engines in claim 2, different types of rotor in claim 3, different temperature/pressure to prevent cavitation in claims 4, 6-8, or different fluids in claims 5, 9 in the apparatus formed by the method steps of claim 5 of US, 12,281,601 for the purpose of generating appropriate work output. The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969). A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b). The filing of a terminal disclaimer by itself is not a complete reply to a nonstatutory double patenting (NSDP) rejection. A complete reply requires that the terminal disclaimer be accompanied by a reply requesting reconsideration of the prior Office action. Even where the NSDP rejection is provisional the reply must be complete. See MPEP § 804, subsection I.B.1. For a reply to a non-final Office action, see 37 CFR 1.111(a). For a reply to final Office action, see 37 CFR 1.113(c). A request for reconsideration while not provided for in 37 CFR 1.113(c) may be filed after final for consideration. See MPEP §§ 706.07(e) and 714.13. The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The actual filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA /25, or PTO/AIA /26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/apply/applying-online/eterminal-disclaimer. Conclusions Any inquiry concerning this communication or earlier communications from the Examiner should be directed to Examiner Nguyen whose telephone number is (571) 272-4861. The examiner can normally be reached on Monday--Thursday from 9:00 AM to 7:00 PM. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Mark Laurenzi, can be reached on (571) 270-7878. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see http://pair-direct.uspto.gov. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). /HOANG M NGUYEN/Primary Examiner, Art Unit 3746 HOANG NGUYEN PRIMARY EXAMINER ART UNIT 3746 Hoang Minh Nguyen 3/5/2026 1
Read full office action

Prosecution Timeline

Mar 17, 2025
Application Filed
Feb 26, 2026
Non-Final Rejection — §DP (current)

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Prosecution Projections

1-2
Expected OA Rounds
76%
Grant Probability
92%
With Interview (+16.4%)
2y 7m
Median Time to Grant
Low
PTA Risk
Based on 1708 resolved cases by this examiner. Grant probability derived from career allow rate.

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