DETAILED ACTION
Notice of Pre-AIA or AIA Status
1. The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Amendment
2. This Office Action is responsive to the amendment filed on 09/11/2025. As directed by the amendment: claims 1-2, 6-9, 13-15 and 17-20 have been amended, claims 3, 10 and 16 have been cancelled, and no claims have been added. Thus, claims 1-2, 4-9, 11-15 and 17-20 are presently pending in this application, claims 4-5 and 11-12 remain withdrawn from consideration.
Claim Objections
3. In light of Applicant's Amendment of 09/11/2025, the objection to claims 1-2, 6-9, 13-15 and 17-20 set forth in the Office Action of 03/11/2025, is hereby withdrawn.
Claims 1-2 and 6-7 are objected to because of the following informalities:
In claim 1, line 26: “receiving the exit stage flow” should be changed to --receiving the second stage exit flow--. --for consistency--.
Claim Rejections - 35 USC § 112
4. In light of Applicant's Amendment of 09/11/2025, the rejection of claims 1-2, 6-9, 13-15 and 17-20 under 35 U.S.C. §112 (pre-AIA ), second paragraph, set forth in the Office Action of 03/11/2025, is hereby withdrawn.
Claim Rejections - 35 USC § 103
5. 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.
6. 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.
7. 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.
8. Claim(s) 1-2, 6, 8-9, 13, 15 and 17-19 are rejected under 35 U.S.C. 103 as being unpatentable over Leroux et al. (hereinafter “Leroux”) (WIPO Publication WO 2022/029386 (A1), Pub. No.: US 2023/0304501 A1 is used for convenience purposes) in view of Spathias et al. (hereinafter “Spathias”) (Pub. No.: US 2021/0310371 A1).
Regarding claims 1, 8 and 15, Leroux discloses a compressor (multi-stage centrifugal compressor 1, as stated Abstract & Paragraph [0076]) for pressurizing a working fluid (to be pressurized and then evacuated radially at its first downstream end, as stated in Paragraph [0026]), comprising:
a motor shaft (motor shaft 4, as discussed in Paragraph [0074]) having a first end (first end or first section 41, as seen in annotated Figure 4) a second end (second end or second opposite section 42 of the motor shaft 4, as shown in annotated Figure 4) and a central axis (motor axis A, see Paragraphs [0072] & [0073]),
a motor (rotary electric motor 2, as described in Paragraphs [0072]-[0074]) driving the motor shaft (as stated in Paragraph [0074], the motor shaft 4 driven in rotation around the motor axis AM by the rotary electric motor 2);
a first stage impeller (first bladed compression impeller 50, as detailed in Paragraph [0077] & [0081]-[0083]) attached to the first end of the motor shaft (being attached to the first end 41 of the motor shaft 4, as illustrated in annotated Figure 4);
a second stage impeller (second bladed compression impeller 60) attached to the second end of the motor shaft (the second bladed compression impeller 60 is surely being attached to the second end 40, as illustrated in annotated Figure 4);
the second stage impeller (second bladed compression impeller 60) in operation creating a second tractive force (second bladed compression impeller 60 is undoubtedly creating the force required to overcome friction and initiate or maintain motion between two surfaces);
a housing (defined by the housing H1 of the multi-stage centrifugal compressor 1, as illustrated in annotated Figure 4) containing the motor shaft (motor shaft 4), the first stage impeller (first bladed compression impeller 50), the second stage impeller (second bladed compression impeller 60), and the motor (rotary electric motor 2),
the first stage impeller (first bladed compression impeller 50) taking in the working fluid (the gaseous fluid) proximate the central axis (through the gaseous fluid inlet 80 that is centered on the motor axis AM, as detailed in Paragraph [0081]).
Particularly, in Paragraphs [0097]-[0098], Leroux performs as how: The multi-stage centrifugal compressor 1 comprises several inter-stage flow passages of gaseous fluid 10 communicating: the first downstream end 52 of the first bladed compression impeller 50, and in particular the first exhaust flow paths 55 of the first diffuser 53 of the first radial compression stage 5.
Especially, in Paragraphs [0082]-[0083], Leroux further discloses: The first bladed compression impeller 50 has an increasing diameter from the first upstream end 51 to the first downstream end 52, and it has blades (also called vanes) which define between them compression channels which are, on the one hand, open at the first upstream end 51 for an inlet of the gaseous fluid and, on the other hand, open at the first downstream end 52 for an outlet of the compressed gaseous fluid. The function of the first diffuser 53 is to straighten and slow down the compressed gaseous fluid at the outlet of the first bladed compression impeller 50. To do this, the first diffuser 53 is provided with first fins 54 distributed around the first downstream end 52 of the first bladed compression impeller 50 and separated by first exhaust flow paths 55. These first exhaust flow paths 55 thus form spaces between the first fins 54, and they are in communication with and in the extension of the compression channels of the first bladed compression impeller 50.
Still further, in Paragraphs [0101]-[0104], Leroux specifies as how: Each inter-stage flow passage of gaseous fluid 10 comprises at least: a main channel 11 made through the motor housing 3 and provided with a main inlet 111 opening into a first exhaust flow path 55, between two first fins 54 of the first diffuser 53, so as to open into the first lateral face 31 of the motor housing 3 to be in communication with the first downstream end 52 of the first bladed compression impeller 50; an intermediate channel 12 in sealed communication with the main channel 11 and passing through a second fin 64 of the second diffuser 63 to emerge on the front face 67 of the second diffuser 63, this second fin 64 thus forming a spacer inserted between the second lateral face 32 of the motor housing 3 and the second cowl 9, wherein this intermediate channel 12 is provided with a main outlet orifice 112 opening into the front face 67; a secondary channel 13 formed in the second cowl 9 which is pressed against the front face 67 of the second diffuser 63, this secondary channel 13 comprising a secondary inlet orifice 131 opening into the annular bearing face 90 of the second cowl 9 and in communication with the main outlet orifice 112 of the intermediate channel 12, and a secondary outlet orifice 132 opening into the inner face of the second cowl 9 opposite the second upstream end 61 of the second bladed compression impeller 60 to form all or part of a gaseous fluid inlet within the second compression stage 6.
Then, in Paragraph [0105], Leroux expressly states that: the gaseous fluid is introduced into the multi-stage centrifugal compressor 1 via the gaseous fluid inlet 80 formed in the first cowl 8, then it is compressed in the first bladed compression impeller 50 to come out at its first downstream end 52, and then the compressed gaseous fluid is straightened in the first exhaust flow paths 55 of the first diffuser 53, and it enters inside the main channels 11, then it passes through the intermediate channels to pass through the second fins 64 of the second diffuser 63 (without being in communication with the second exhaust flow paths 65) to enter the secondary channels 13, which will allow the compressed gaseous fluid to come out opposite the second upstream end 61 of the second bladed compression impeller 60, and thus this compressed gaseous fluid is compressed in the second bladed compression impeller 60 to emerge at its second downstream end 62, and the compressed gaseous fluid thus compressed twice is collected in the outlet manifold 7.
Accordingly, the Examiner must assert that the second exhaust flow paths 65, which are designated as outlet transfer passages would be necessarily keeping the interstage flow IF separate from the second stage exit flow, as instantly claimed.
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Leroux, in Paragraph [0123], then goes on to describe how: Each secondary channel 13 has a curved section between its secondary inlet orifice 131 and its secondary outlet orifice 132, according to an angular amplitude comprised between 150 and 180 degrees, to define a reversal of the flow in the secondary channel 13. Indeed, as each secondary channel 13 only opens into the inner face of the second cowl 9 at its secondary inlet orifice 131 and its secondary outlet orifice 132, the secondary channel 13 causes the fluid to make a sort of U-turn compressed gas. The secondary outlet orifices 132 are provided at the level of the center of the second cowl 9. Deflector flaps 92 can be provided on the second cowl 9, opposite the secondary outlet orifices 132 of each secondary channel 13, in order to deflect the gaseous fluid leaving the secondary channels 13 in the direction of the second downstream end 62 of the second bladed compression impeller 60.
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In fact, Leroux explicitly exhibits as how the first stage impeller or first bladed compression impeller 50 taking in the working fluid or gaseous fluid proximate the central axis or motor axis AM and discharging an interstage flow IF and/or how an internal passage, which is defined by the main channel 11, carrying the interstage flow IF within the housing H1 and/or how the internal passage or main channel 11 including a plurality of second stage transfer passages or secondary channels 13, with each of the second stage transfer passages receiving a portion of the interstage flow IF, bending the interstage flow IF through approximately 180 degrees, and directing the interstage flow IF into the second stage impeller 60, as otherwise, the system cannot normally operate.
Furthermore, in Paragraph [0122], Leroux especially teachers that: the shape and dimensions of the main inlet orifices 111 depend on the shape and dimensions of the first exhaust flow paths 55, and likewise the shape and dimensions of the main outlet orifices 112 depend on the shape and dimensions of the second fins 64. Also, insofar as the first exhaust flow paths 55 do not have the same shapes and dimensions as the second fins 64, then the main inlet orifices 111 do not have the same shapes and dimensions than the main outlet orifices 112. Therefore, each main channel 11 has a variable cross-section between its main inlet orifice 111 and the main outlet orifice 112.
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Essentially, with reference to annotated Figures 2 and 3, Leroux’s compressor is surely designed such that a plurality of outlet transfer passages or second exhaust flow paths 65, with each of the outlet transfer passages 65 receiving a portion of the second stage exit flow and carrying it to an outlet and/or the plurality of second stage transfer passages or secondary channels 13 and the outlet transfer passages 65 passing by each other in proximity to the second stage impeller or second bladed compression impeller 60, with the second stage transfer passages or secondary channels 13 and the outlet transfer passages or second exhaust flow paths 65 keeping the interstage flow IF separate from the second stage outlet flow, as instantly claimed.
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Especially, in Paragraph [0096], Leroux also teaches: The multi-stage centrifugal compressor 1 comprises an outlet manifold 7 secured to the motor housing 3, which has an outlet volute 70 in communication with the second exhaust flow paths 65 of the second diffuser 63. This outlet manifold 7 is fixed on an annular flange 35 provided on the peripheral face 33 of the motor housing 3, so that the outlet volute 70 surrounds the second diffuser 63 and its second exhaust flow paths 65.
Then, as best seen immediately above, Leroux surely exhibits as how an internal passage, which is defined by the main channel 11, carrying the interstage flow and/or the second stage impeller taking in the interstage flow proximate the central axis and discharging a second stage exit flow in a direction perpendicular to the central axis AM.
Furthermore, it’s a well-established fact that the tractive force, also called traction force, is the force required to overcome friction and initiate or maintain motion between two surfaces that are in contact, essentially the force generated through friction that allows an object to move across a surface by resisting opposing forces like rolling resistance or air resistance; it acts in the opposite direction to the friction force itself.
Traction1 is often expressed as the ratio or fraction of the maximum tractive force to the normal force when the maximum tractive force between a body and a surface is limited by the available friction. Coefficient of traction = Usable traction / Normal force.
As such, the Examiner must assert that the second stage impeller or second bladed compression impeller 60 in operation surely creating a second tractive force that opposes a first tractive force created by the first stage impeller or first bladed compression impeller 50, as otherwise, the system cannot normally operate.
Although Leroux discloses the majority of Applicant’s claimed elements, he is still silent as to the fact that a plurality of outlet transfer passages, with each of the outlet transfer passages bending the second stage exit flow to be parallel with the central axis and/or an outlet receiving the exit stage flow from the plurality of outlet transfer passages, the outlet being aligned with the central axis.
Nevertheless, the use of outlets being aligned with the central axis is well-known in the art, as taught by Spathias. Spathias in the same field of endeavor successfully teaches a turbomachine, wherein, as stated in Paragraph [0025], the turbine section 113 may include the turbine wheel 131, which is housed within a turbine housing 188 of the housing assembly 119. The turbine housing 188 may define a turbine flow path 190 with a volute inlet passage 192 and an axial tubular outlet 194 that is centered on the axis 120.
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Spathias, in Paragraph [0021], successfully teaches that: The compressor housing 152 may include a tubular inlet 153 that is centered on the axis 120. The compressor housing 152 may also be hollow and a flow path 151 may extend axially in a downstream direction and then may turn outward radially with respect to the axis 120
Most importantly, however, is the specific arrangement of the outlet 194 that is clearly aligned with the central axis 120 while being aligned with the inlet 153.
Consequently, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to combine the teaching of using an outlet that is being aligned with the central axis, as taught by Spathias, in the compressor as part of an obvious combination of known prior art structures, in this case the use of an outlet being aligned with a central axis in the compressor, to achieve predictable results, in this case, to further control the fluid flow through the system. See KSR; MPEP 2141 III A.
Thus modified, one skilled in the art would have been reasonably appraised that the second stage impeller will be further taking in the interstage flow proximate the central axis and discharging a second stage exit flow in a direction perpendicular to the central axis and/or a plurality of outlet transfer passages, with each of the outlet transfer passages receiving a portion of the second stage exit flow and will be further bending the second stage exit flow to be parallel with the central axis and/or an outlet will be further receiving the exit stage flow from the plurality of outlet transfer passages and/or the outlet will be further aligned with the central axis and/or the plurality of second stage transfer passages and the outlet transfer passages passing by each other in proximity to the second stage impeller, with the second stage transfer passages and the outlet transfer passages will be further keeping the interstage flow separate from the second stage exit flow and/or the plurality of outlet transfer passages will be further bending the second stage exit flow toward the central axis and into the outlet and/or an outlet will be further aligned with the inlet and/or an outlet transfer passage will be further bending the second stage exit flow toward the central axis and carrying the second stage exit flow to the outlet, as instantly claimed.
Thus, the combination of Leroux and Spathias appears to disclose all aspects of Applicant's claimed invention.
Regarding claims 2, 9 and 17, Leroux and Spathias substantially disclose the compressor, as claimed and detailed above. Additionally, in Paragraph [0096], Leroux explicitly teaches that: The multi-stage centrifugal compressor 1 comprises an outlet manifold 7 secured to the motor housing 3, which has an outlet volute 70 in communication with the second exhaust flow paths 65 of the second diffuser 63. This outlet manifold 7 is fixed on an annular flange 35 provided on the peripheral face 33 of the motor housing 3, so that the outlet volute 70 surrounds the second diffuser 63 and its second exhaust flow paths 65.
As best seen in annotated Figure 3, Leroux evidently illustrates as how the outlet transfer passages 65 join to form a single outlet and/or how the single outlet, which is defined by the outlet manifold, lies proximate the central axis or motor axis AM
As such, according to the combination, one skilled in the art would surely recognize that the outlet transfer passages will be further joining to further form the outlet while the outlet will be further lying proximate the central axis AM, as instantly claimed.
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Regarding claims 6, 13 and 18-19, Leroux and Spathias substantially disclose the compressor for pressuring the working fluid, as claimed and detailed above. Additionally, in claims [0047]-[0048], Leroux specifically teaches as how: a cooling circuit provided in the motor housing for a circulation of coolant inside the motor housing. In this way, the gaseous fluid circulating in the main channel of the or each of the inter-stage flow passages of gaseous fluid, which is heated at the outlet of the first stage, can be cooled by heat exchange with this cooling circuit. Indeed, thanks to the present disclosure, this or these main channels are provided in the motor housing, in heat-conducting material, and therefore the surfaces offered by the main channel or channels and the circulation of water in the cooling circuit allow to evacuate the heat. In other words, the present disclosure makes it possible to use this cooling circuit for a dual purpose, namely to cool the rotary electric motor and cools the gaseous fluid passing from the first compression stage towards the second compression stage, which is interesting from a compact and also economical point of view.
More specifically, in Paragraph [0049], Leroux further states that: the cooling circuit has one or more sections contiguous to the main channel of the inter-stage flow passage of gaseous fluid or of one of the inter-stage flow passages of gaseous fluid.
Moreover, in Paragraph [0119], Leroux specifies that: the cooling circuit 36, provided in the motor housing 3, has one or more sections contiguous to the main channels 11, which has the advantage of cooling the compressed gaseous fluid leaving the first stage of radial compression 5, before entering the second radial compression stage 6. Such cooling of the gaseous fluid between the two radial compression stages 5, 6 makes it possible to increase the density of the gaseous fluid and thus to reduce the sections of the main channels 11. In addition, the cooling of the gaseous fluid between the two radial compression stages 5, 6 makes it possible to limit the final temperature of the gaseous fluid and therefore the energy consumption, and thus to improve the performance of the multi-stage centrifugal compressor 1.
As such, according to the combination, one of ordinary skill in the art would surely recognize that a portion of the interstage flow would be further directed around the motor in order to further cool the motor, as instantly claimed.
9. Claims 7, 14 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Leroux in view of Spathias, and further in view of Lee et al. (hereinafter “Lee”) (Pub. No.: US 2021/0324876 A1).
Regarding claims 7, 14 and 20, Leroux and Spathias substantially disclose the compressor for pressuring the working fluid, as claimed and detailed above. However, although Leroux and Spathias disclose the vast majority of Applicant’s claimed elements, it is still silent as to the fact an economizer inlet positioned to direct return flow from an economizer around the motor in order to cool the motor.
Nevertheless, the use of economizers is well-known in the art, as taught by Lee.
Lee successfully performs another compressor that, as stated in Abstract, is including: a motor having a rotating shaft; a first impeller housing forming a first inlet, through which a first refrigerant flows, and having a chamber into which a second refrigerant flows; a first impeller coupled to one end of the rotating shaft, and rotatably received in the first impeller housing; a diffuser spaced apart from an inside of the first impeller housing, and forming a first outlet; a second impeller housing having a second inlet formed therein; a second impeller coupled to the other end of the rotating shaft, and rotatably received in the second impeller housing; a volute case in which a volute is formed; and a motor housing having a connecting passage formed therein and connecting the first outlet and the second inlet.
Further, in Paragraph [0049]-[0052], Lee especially teaches: In order to improve compression efficiency, the compressor 2 may be formed as a two-stage compressor having a first compressor 10 and a second compressor 20. A chiller using such two-stage compressor may further include an economizer 70 configured to separate a refrigerant, having a mixture of two phases discharged from the first expander 40, into a gaseous phase and a liquid phase. However, if the gaseous refrigerant flowing from the economizer 70 into the second compressor 20 hinders the flow of a refrigerant having passed through the first compressor 10, compression efficiency of the two-stage compressor 2 may be reduced. A compressor according to FIGS. 2 to 8, which will be described below, is an example of a compressor including a first impeller housing and a diffuser for minimizing hindrance to the flow of the refrigerant having passed through the first compressor 10, which is caused by the gaseous refrigerant flowing from the economizer 70 into the second compressor 20. In the following description, a first impeller refers to the first compressor 10; a second impeller refers to the second compressor 20; a first refrigerant refers to a refrigerant evaporated by passing through the evaporator 60; and a second refrigerant refers to a gaseous refrigerant separated by the economizer 70.
Still further, in Paragraph [0084], Lee discloses: The first impeller housing 111 may further include a second refrigerant inlet 112 allowing a discharge tube of the economizer and the chamber R to communicate with each other, and a second refrigerant output 113 allowing the chamber R and the first outlet 135 to communicate with each other. The second refrigerant inlet 112 may allow the second refrigerant to flow from the economizer to the chamber R, and the second refrigerant outlet 113 may allow the second refrigerant to flow from the chamber R to the first outlet 135.
Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to combine the teaching of using an economizer, as taught by Lee, to the compressor of Leroux/ Spathias in order to further improve compression efficiency, as motivated by Lee in Paragraph [0049].
Thus modified, one skilled in the art would have been reasonably appraised that the compressor would be further comprising an economizer inlet that would be further positioned to further direct return flow from an economizer around the motor in order to further cool the motor, as instantly claimed.
Prior Art
10. The prior art made of record and not relied upon is considered pertinent to applicant's disclosure and consists of five patents.
US 2021/0324860 A1, US 2021/0010478 A1, US 2020/0263698 A1, US 2023/0313812 A1 and US 11,698,074 B2 are cited to show different compressors, wherein a first impeller, which is configured to primarily compress the refrigerant introduced into the refrigerant suction hole, is coupled to one end of the rotation shaft and a second impeller is being coupled to the other end of the rotation shaft.
Response to Arguments
11. Applicant's arguments filed 09/11/2025 have been fully considered but they are moot because the arguments do not apply to the combination of references being used in the current rejection. Further, the Examiner notes that the newly applied reference addresses the applicant's arguments as set forth in the above rejections.
Conclusion
12. Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any extension fee pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to LILYA PEKARSKAYA whose telephone number is (571)272-1158. The examiner can normally be reached on Monday to Friday, 9:00-5:00 EST.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Essama Omgba can be reached on 469-295-9278. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/LILYA PEKARSKAYA/Examiner, Art Unit 3746
/ESSAMA OMGBA/Supervisory Patent Examiner, Art Unit 3746
1 https:// https://byjus.com/physics/traction-force/- Accessed 03/05/2025.