Prosecution Insights
Last updated: April 19, 2026
Application No. 18/275,883

COMPRESSOR, IN PARTICULAR REFRIGERANT COMPRESSOR, REFRIGERATION MACHINE, AND METHOD FOR PRODUCING A COMPRESSOR

Non-Final OA §103
Filed
Aug 04, 2023
Examiner
TAVAKOLDAVANI, KAMRAN
Art Unit
3763
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Thyssenkrupp AG
OA Round
3 (Non-Final)
83%
Grant Probability
Favorable
3-4
OA Rounds
2y 6m
To Grant
90%
With Interview

Examiner Intelligence

Grants 83% — above average
83%
Career Allow Rate
351 granted / 424 resolved
+12.8% vs TC avg
Moderate +7% lift
Without
With
+6.8%
Interview Lift
resolved cases with interview
Typical timeline
2y 6m
Avg Prosecution
57 currently pending
Career history
481
Total Applications
across all art units

Statute-Specific Performance

§101
0.2%
-39.8% vs TC avg
§103
46.4%
+6.4% vs TC avg
§102
24.8%
-15.2% vs TC avg
§112
28.0%
-12.0% vs TC avg
Black line = Tech Center average estimate • Based on career data from 424 resolved cases

Office Action

§103
DETAILED ACTION This office action is set to be a second non-final action, thus replacing the non-final action posted on 9/16/2025. A new ground(s) of rejections have been made, therefore, the office action posted on 9/16/2025 is withdrawn. Claim 11 is withdrawn. 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 . 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. Claims 1, 2, 4, 7-10, 12 are rejected under 35 U.S.C. 103 as being unpatentable over Feller (US 2016/0097572 A1), in view of Gurin (US 2011/0030404 A1). Claim 1: Feller discloses a compressor (i.e., FIG.1) comprising: a low pressure region (i.e., annotated FIG.1; low pressure side 36, as annotated the low pressure region is to the left section/part of side 36); a high pressure region (i.e., chamber 46 used as high pressure region; paragraph [49]: high pressure mixture entering chamber 46); a lubricant (i.e., paragraph [56]: purpose of lubricating bearings of compressor in lower pressure section supplied from oil sump) is provided in the low pressure region (i.e., annotated FIG.1) configured to lubricate the compressor (i.e., 12); a fluid (i.e., paragraph [49]: refrigerant used as fluid) is configured to be conveyed from the low-pressure region (i.e., annotated FIG.1) into the high- pressure region (i.e., 46) and compressed (i.e., paragraph [49]: refrigerant compressed), wherein a portion (i.e., inherent) of the lubricant with the fluid from the low-pressure region (i.e., annotated FIG.1) is configured to reaches the high-pressure region (i.e., 46); a lubricant separator (i.e., 52/54) for separating the lubricant from the fluid in the high pressure region (i.e., 46); and a lubricant return channel (i.e., channel 42 used as lubricant return channel) for transporting the separated lubricant from the high- pressure region (i.e., 46) into the low-pressure region (i.e., annotated FIG.1), wherein the lubricant return channel (i.e., 42) is formed in a housing (i.e., 16), a sealing face, and/or in a seal of the compressor. PNG media_image1.png 451 756 media_image1.png Greyscale Feller discloses the claimed limitations in claim 1, but fails to disclose includes a fluid diode, wherein the lubricant return channel is a planar partition face. However, Gurin teaches a fluid diode (paragraph [59]: fluid diode 700; to clarify, fluid diode 700 is on a tube between heat exchanger and condenser) for the purpose of regulating the fluid flow to prevent backflow (paragraph [59]). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filling date of the claimed invention was made to modify the invention of Feller to include a fluid diode as taught by Gurin to be on the lubricant return channel of Feller in order to regulate the fluid flow to prevent backflow. Further, Gurin discloses the lubricant return channel, except for in a planar partition face. The court held that the configuration of the claimed was a matter of choice which a person of ordinary skill in the art would have found obvious absent persuasive evidence that particular configuration of the claimed was significant - Change of Shape: MPEP 2144.04. Claim 2: Feller as modified discloses the apparatus as claimed in claim 1, wherein the lubricant return channel (i.e., 42) includes an inner wall (inherent) in order to form the fluid diode (Gurin 700), except for a heart shaped or offset heart shaped. The configuration/shape of the claimed inner wall is a matter of choice which a person of ordinary skill in the art would have found obvious absent persuasive evidence that the particular configuration/shape of the claimed inner wall a heart shaped or offset heart shaped is significant in order to enhance the fluid flow rate through the channel (Change of Shape: MPEP 2144.04). Claim 4: Feller as modified discloses the apparatus as claimed in claim 1, except for wherein the lubricant return channel is shaped in a semi-circular manner. The configuration/shape of the claimed lubricant channel is shaped in a semi-circular manner is a matter of choice which a person of ordinary skill in the art would have found obvious absent persuasive evidence that the particular configuration/shape of the claimed lubricant return channel is shaped in a semi-circular manner is significant in order to enhance the fluid flow rate through the channel (Change of Shape: MPEP 2144.04). Claim 7: Feller as modified discloses the apparatus as claimed in claim 1, wherein the lubricant is oil (i.e., paragraph [56]: lubricant oil sump). Claim 8: Feller fails to disclose wherein a configuration of an inner wall of the lubricant return channel, is produced by means of punching, etching or erosion. This rejection under 35 U.S.C. 103 is proper because the "even though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process." The combination of previous references meets the structural limitations put forth in Claim 8, wherein the final product existing after fabrication is compared to prior art for the purposes of patentability. The limitations regarding “produced by means of punching, etching or erosion” are drawn to method of production and not the structural aspects of the instant invention (MPEP 2113). Claim 9: Feller as modified discloses the apparatus as claimed in claim 1, wherein the lubricant return channel (i.e., 42) includes the fluid diode (Gurin 700) as a separate component. Claim 10: Feller discloses a refrigeration machine comprising: a compressor (i.e., 12), wherein the compressor (i.e., 12) includes: a low pressure region (i.e., annotated FIG.1; low pressure side 36, as annotated the low pressure region is to the left section/part of side 36); a high pressure region (i.e., chamber 46 used as high pressure region; paragraph [49]: high pressure mixture entering chamber 46); a lubricant provided (i.e., paragraph [56]: purpose of lubricating bearings of compressor in lower pressure section supplied from oil sump) in the low pressure region (i.e., low pressure side 36) configured to lubricate the compressor (i.e., 12); a fluid (i.e., paragraph [49]: refrigerant used as fluid) configured to be conveyed from the low pressure region (i.e., low pressure side 36) into the high pressure region (i.e., 46) and compressed, wherein a portion of the lubricant with the fluid from the low pressure region (i.e., low pressure side 36) is configured to reach the high pressure region (i.e., 46); a lubricant separator (i.e., 52/54) for separating the lubricant from the fluid in the high pressure region (i.e., 46); and a lubricant return channel (i.e., channel 42 used as lubricant return channel) for transporting the separated lubricant from the high pressure region (i.e., 46) into the low pressure region (i.e., low pressure side 36), wherein the lubricant return channel (i.e., 42) is formed in a housing (i.e., 16), a sealing face, and/or in a seal of the compressor. Feller discloses the claimed limitations in claim 10, but fails to disclose a gas cooler, an expansion valve and an evaporator, which are fluidically connected to each other, wherein includes a fluid diode, wherein the lubricant return channel is a planar partition face. However, Gurin teaches a gas cooler (evaporative cooler 920), an expansion valve (90) and an evaporator (80), which are fluidically connected to each other, wherein includes a fluid diode (paragraph [59]: fluid diode 700; to clarify, fluid diode 700 is on a tube between heat exchanger and condenser) for the purpose of regulating the fluid flow to prevent backflow (paragraph [59]). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filling date of the claimed invention was made to modify the invention of Feller to include a gas cooler, an expansion valve and an evaporator, which are fluidically connected to each other, includes a fluid diode as taught by Gurin to be on the lubricant return channel of Feller in order to regulate the fluid flow to prevent backflow. Further, Gurin discloses the lubricant return channel, except for in a planar partition face. The court held that the configuration of the claimed was a matter of choice which a person of ordinary skill in the art would have found obvious absent persuasive evidence that particular configuration of the claimed was significant - Change of Shape: MPEP 2144.04. Claim 12: Feller as modified discloses the apparatus as claimed in claim 1, wherein the lubricant return channel (i.e., 42) is at least partially in the form of a fluid diode (Gurin 700). Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Feller (US 2016/0097572 A1), Gurin (US 2011/0030404 A1), and in view of Thiessen (US 2017/0016652 A1). Claim 3: Feller as modified discloses the lubricant return channel, except for introduced into a metal sheet. However, Thiessen teaches a metal sheet (i.e., paragraph [37]: metal pipes) for the purpose of enhancing the strength of the channel. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filling date of the claimed invention was made to further modify the apparatus of Feller to include the channel is introduced into a metal sheet as taught by Thiessen, since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended in order to enhance the strength of the channel. Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Feller (US 2016/0097572 A1), Gurin (US 2011/0030404 A1), and in view of Roullet (US 2022/0196310 A1). Claim 6: Feller as modified further fails to disclose wherein the fluid is a refrigerant, in particular supercritical CO2. However, Roullet teaches the fluid is a refrigerant, in particular supercritical CO2 (i.e., paragraph [15]) for the purpose utilizing refrigerants efficiently having a normal boiling point also referred as low pressure refrigerants (paragraph [15]). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filling date of the claimed invention was made to further modify the apparatus of Feller to include the fluid is a refrigerant, in particular supercritical CO2 as taught by Roullet in order to utilize refrigerants efficiently having a normal boiling point also referred as low pressure refrigerants. Response to Arguments Applicant's arguments submitted on 7/18/2025 with respect to claims 1 and 10 under Claim Rejections - 35 USC § 103 have been fully considered, but they are not persuasive. Applicant’s argument on page 6: “Gurin does not teach or suggest use of a fluid diode in connection with a lubricant separator in a high pressure region, or a lubricant return channel”. Examiner respectfully disagrees, because Gurin is only used to teach a fluid diode. However, the primary art Feller discloses a lubricant separator in a high pressure region, and also Feller discloses a lubricant return channel as indicated in the office action above. Further, the function of the diode fluid is not claimed. Feller is only modified to include a fluid diode 700 as taught by Gurin in order to regulate the fluid flow to prevent backflow. Note that fluid diode 700 is disposed on a tube between two structures. Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure which is relevant to compressor: Tamura (US 2019/0131844 A1). Any inquiry concerning this communication or earlier communications from the examiner should be directed to KAMRAN TAVAKOLDAVANI whose telephone number is (313)446-6612. The examiner can normally be reached on M-F 8:00 am to 5:00 pm 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, Len Tran can be reached on (571) 272-1184. 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). If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /KAMRAN TAVAKOLDAVANI/Examiner, Art Unit 3763 /LEN TRAN/Supervisory Patent Examiner, Art Unit 3763
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Prosecution Timeline

Aug 04, 2023
Application Filed
Mar 13, 2025
Non-Final Rejection — §103
Jun 18, 2025
Examiner Interview Summary
Jun 18, 2025
Applicant Interview (Telephonic)
Jul 18, 2025
Response Filed
Sep 08, 2025
Non-Final Rejection — §103
Dec 15, 2025
Response Filed
Dec 15, 2025
Examiner Interview Summary
Dec 15, 2025
Applicant Interview (Telephonic)
Jan 22, 2026
Non-Final Rejection — §103 (current)

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

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Prosecution Projections

3-4
Expected OA Rounds
83%
Grant Probability
90%
With Interview (+6.8%)
2y 6m
Median Time to Grant
High
PTA Risk
Based on 424 resolved cases by this examiner. Grant probability derived from career allow rate.

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