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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 11/19/2025 has been entered.
Response to Arguments
Applicant's remarks filed 11/03/2025 have been fully considered.
Regarding the remarks regarding “%M” (para 3 of page 8 of Applicant’s remarks), it is noted Applicant has not presented an argument. Applicant directs towards the reference US 20220333613 A1 (hereinafter Li’613) which identifies a “fractional meridional distance”. Li’613 however does not identify “%M” and does not connect Applicant’s use of “%M” with a “fractional meridional distance” or a “percent of meridional chord”.
Regarding the prior drawing objections, claim objections, Applicant’s amendments overcome all prior objections.
Regarding the prior art rejection of claim 1, in paragraph 3 of page 9 of Applicant’s Remarks, Applicant’s arguments are directed to that Li’613 fails to disclose, teach, or suggest the amended limitations of amended claim 1.
Applicant’s arguments are moot in light of the new rejections; please see the action below for details of the new rejections.
Regarding the prior art rejection of claim 5, in paragraphs 4-5 of page 9 of Applicant’s Remarks, Applicant’s arguments are directed to that Li’613 is silent as to any notion of a backsweep of trailing edge of a main vane differing in value from a backsweep of a trailing edge of a splitter vane.
Applicant’s arguments are moot in light of the new rejections; please see the action below for details of the new rejections.
Regarding the prior art rejection of claim 5, in paragraph 1 of page 10 of Applicant’s Remarks, Applicant’s arguments are directed to that a rejection identifying that a change in form, proportions, or degree, is not inventive, with respect to Li’613, is improper because Applicant’s disclosure identifies (para 0037) “Higher backsweep of the splitter blades increases the performance of the centrifugal stage on the choke side of the speedline. Additional benefits of a difference in backsweep of main blades and splitter blades can include an ability to intentionally mis-tune the impeller and the diffuser.” Insofar as the argument may apply to the claim 5 rejection below relying on the reference Li’670, it is noted that the argument is not persuasive because Applicant’s citation above identifies a criticality for a difference in backsweep between main blades and splitter blades, not a criticality for a difference of 5 degrees, and the related rejection was directed at the claimed difference of 5 degrees.
Claim Interpretation
Examiner’s note: The previous claim interpretations (identified in the office action mailed on 5/12/2025) regarding the terms “about” (interpreted to mean “to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application” as identified in paragraph 0051) and “an impeller knee” (interpreted to mean “a range of locations where the flow path 351 changes from a predominantly axial direction to a predominantly radial direction” as identified in paragraph 0043) are maintained.
Claim Rejections - 35 USC § 112(b)
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.
Claim(s) 8 is/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 8 recites the limitation “an absolute value of a value of the backsweep of the first degree exhibited by the trailing edge of the splitter vane exceeds an absolute value of a value of the backsweep of the second degree exhibited by the trailing edge of the main vane from 50% chord to 100% chord” which renders the claim indefinite because it is unclear what it means for a value (or two values in this case) at or associated with the trailing edge to exist or be associated with a value from 50% chord to 100% chord, or because it is unclear how a value (or two values in this case) can be at or associated with the trailing edge and also exist or be associated with a value from 50% chord to 100% chord.
In view of the 112(b) rejections set forth above, the claims are rejected below as best understood.
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) 1-6, 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 11976670 B2 (hereinafter Li’670) in view of US 20160238018 A1 (Conner).
Examiner’s note: All mapping below (references made to reference characters, figures, paragraphs, etc.) is with regard to the base reference (the first reference identified above) unless otherwise noted.
Regarding claim 1, Li’670discloses:
A centrifugal compressor, the centrifugal compressor comprising:
an impeller (500; Fig 5A-5C) comprising a hub (504), main and splitter vanes (510, 520) and a shroud (420; Fig 4A) surrounding the hub and the main and splitter vanes to form a flow path from an inducer portion (impeller inlet; Fig 4A) at an upstream side of the impeller to an exducer portion (impeller outlet; Fig 4A) at an impeller exit (Fig 4A shows all this),
the main vanes extending from the inducer portion to the exducer portion and the splitter vanes being interleaved with the main vanes and extending to the exducer portion from an impeller mid-point (Annotated Fig 4Aa) (Fig 4A and Fig 5B show all this),
and each main and splitter vane comprising, at the impeller exit, a trailing edge (518, 528; Fig 5B),
and, for one or more pairs of main and splitter vanes:
the trailing edge of the splitter vane exhibits backsweep of a first degree (B2; Fig 5A; e.g. col 15 lines 4-9: “a back sweep angle B2 of the splitter blades 520 at the trailing edge 528 may be a high back sweep angle equal to or greater than approximately 45°, such as approximately 45° to approximately 65°, including approximately 50° to 60°.”)
and the trailing edge of the main vane exhibits backsweep of a second degree (B1; Fig 5A; e.g. col 14 lines 25-35: “a back sweep angle B1 of the full blades 510 at the trailing edge 518 may be a high back sweep angle equal to or greater than approximately 45°, such as approximately 45° to approximately 65°, including approximately 50° to 60°.”) which differs in value from the backsweep of the first degree (the disclosure identifies that B1 and B2 may be different values; e.g. Fig 5A illustrates B1 and B2 as different angles; e.g. col 1 lines 60-63; e.g. col 14 lines 25-35 and col 15 lines 4-9; e.g. col 3 line 38, which indicates that the splitter blades and the full blades may have different back sweep angles at the trailing edge, particularly via the term “or” in “The blades, including the splitter blades and/or the full blades, may have high back swept angles at a trailing edge.”).
Li’670 may not explicitly disclose:
The centrifugal compressor is of an aircraft gas turbine engine
However, Conner, in the same field of endeavor, compressors, teaches:
In Fig 2 an analogous centrifugal compressor 32 located within an aircraft gas turbine engine (20; Fig 1).
Therefore, it would have been obvious to a person having ordinary skill in the art, before the effective filing date of the claimed invention, to modify Li’670 as modified above to include Conner’s teachings, having Li’670’s centrifugal compressor located within an aircraft gas turbine engine, in order to have the compressor operate within an aircraft gas turbine engine.
This claim limitation is essentially directed to the environment of use, wherein the claimed centrifugal compressor is used within an aircraft gas turbine engine, and Conner teaches an aircraft gas turbine engine that uses a centrifugal compressor.
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Annotated Fig 4Aa
Regarding claim 2, Li’670, as modified above, discloses:
the impeller mid-point is defined as an impeller knee (it is a knee), which is interposed between the inducer and exducer portions (Fig 4A and Fig 5B show all this).
Regarding claim 3, Li’670, as modified above, discloses:
the trailing edge of the main vane of the one or more pairs of main and splitter vanes comprises
a main vane hub-side trailing edge portion, which is adjacent to the hub,
a main vane shroud-side trailing edge portion, which is displaced from the shroud,
and a main vane central trailing edge portion interposed between the main vane hub-side trailing edge portion and the main vane shroud-side trailing edge portion (Fig 4A and Fig 5B show all this),
and the trailing edge of the splitter vane of the one or more pairs of main and splitter vanes comprises
a splitter vane hub-side trailing edge portion, which is adjacent to the hub,
a splitter vane shroud-side trailing edge portion, which is displaced from the shroud,
and a splitter vane central trailing edge portion interposed between the splitter vane hub-side trailing edge portion and the splitter vane shroud-side trailing edge portion (Fig 4A and Fig 5B show all this).
Regarding claim 4, Li’670, as modified above, discloses:
the trailing edge of the main vane of the one or more pairs of main and splitter vanes exhibits a same backsweep at the main vane hub-side trailing edge portion and at the main vane shroud-side trailing edge portion (Fig 7 clearly shows that the backsweep (vertical axis) of the main vane at the hub (plot 702) and at the shroud (plot 704) at the trailing edge (“1” on horizontal axis) are the same value. Col 17 lines 28-49 identify that diagram 700 in Fig 7 describes the backsweep angle (vertical axis) of the full blade 510; plot 702 is the backsweep angle of the blade at the hub surface 504 and plot 704 is the backsweep angle of the blade at the shroud side surface 514, wherein "1" on the horizontal axis is the trailing edge.),
and the trailing edge of the splitter vane of the one or more pairs of main and splitter vanes exhibits a same backsweep at the splitter vane hub-side trailing edge portion and at the splitter vane shroud-side trailing edge portion (Fig 7 clearly shows this for the splitter vane too. Col 17 lines 64-67 identifies that diagram 700 in Fig 7 similarly describes the splitter blade 520.).
Regarding claim 5, Li’670, as modified above, discloses:
for the one or more pairs of main and splitter vanes, the backsweep of the first degree exhibited by the trailing edge of the splitter vane differs in value from the backsweep of the second degree exhibited by the trailing edge of the main vane by a value of degrees (B1 and B2 of Fig 5A; e.g. col 14 lines 25-35: “a back sweep angle B1 of the full blades 510 at the trailing edge 518 may be a high back sweep angle equal to or greater than approximately 45°, such as approximately 45° to approximately 65°, including approximately 50° to 60°.” and col 15 lines 4-9: “a back sweep angle B2 of the splitter blades 520 at the trailing edge 528 may be a high back sweep angle equal to or greater than approximately 45°, such as approximately 45° to approximately 65°, including approximately 50° to 60°.”).
Li’670 may not explicitly disclose:
The value of degrees is about 5 degrees.
However, courts have established that a change in form, proportions, or degree, will not sustain a patent and is not inventive, rather a form of routine optimization which would be obvious to a person having ordinary skill in the art. In this case, Li’670 discloses that B1 may have a value of 50° to 60° (e.g. col 14 lines 25-35), and that B2 may have a value of 50° to 60° (e.g. col 15 lines 4-9), indicating a difference of up to 10° between B1 and B2, also Fig 5A shows that the angles B1 and B2 are only slightly different. Because the prior art’s difference (up to 10° identified by the prior art vs the claimed 5°) would be understood by one of ordinary skill to be in the same general range contemplated by the claim, the difference is held to be obvious. See MPEP 2144.05(II). One would optimize Li’670’s backsweep angle to optimize efficiency and noise reduction of the impeller (Li’670 col 3 lines 35-57).
Regarding claim 6, Li’670, as modified above, discloses:
for the one or more pairs of main and splitter vanes,
an absolute value of a value of the backsweep of the first degree exhibited by the trailing edge of the splitter vane exceeds an absolute value of a value of the backsweep of the second degree exhibited by the trailing edge of the main vane (Li’670’s Fig 5 shows that the angle of B2 exceeds the angle of B1).
Regarding claim 8, Li’670, as modified above, discloses:
for the one or more pairs of main and splitter vanes,
an absolute value of a value of the backsweep of the first degree exhibited by the trailing edge of the splitter vane exceeds an absolute value of a value of the backsweep of the second degree exhibited by the trailing edge of the main vane from 50% chord to 100% chord (see related 112b rejection above; e.g. col 1 lines 63-67: “An absolute value of the back sweep angles of a majority of a length of the splitter blades is higher than an absolute value of the back sweep angles of a majority of the length of the full blades”).
It is also noted that a broadest reasonable interpretation of the term “by” in the limitation “by the trailing edge” may be “near”, as in “near the trailing edge”. Also, a trailing edge may be a region, as one having ordinary skill in the art would understand; see for example the image with the trailing edge emphasized as a region at https://web.archive.org/web/20170327232357/https://en.wikipedia.org/wiki/Trailing_edge, which is archived on Mar 23 2017.
Claim(s) 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over the prior art reference(s) as applied to claim 1 above, and further in view of CN 108443218 A (hereinafter Wang).
Regarding claim 9, Li’670, as modified above, discloses all claim limitations (see above) except:
for the one or more pairs of main and splitter vanes,
a value of the backsweep of the first degree exhibited by the trailing edge of the splitter vane is variable from one splitter vane to another.
However, Wang, in the same field of endeavor, impellers, teaches:
A centrifugal impeller (Fig 1) applicable in aerospace applications (lines 33-36) which comprises full/long blades (3) and three different type of splitter blades (primary splitting blade 4, secondary splitter blade 5, secondary splitter blade two 6), wherein the long blade 3 comprises a sweep angle β2 at the outlet (claim 2) and the splitter blade 5 comprises a different sweep angle β24 at the outlet (claim 3) and splitter blade 6 comprises a unique thickness profile relative to the splitter blades 4 and 5 (Fig 1), which inherently results in a backsweep angle which is varied between the splitter blades 6 compared to that of splitter blades 4 and 5, in order to improve pump efficiency (lines 64-68; note that while line 63 discusses hydraulic loss this does not discredit the benefits discussed in lines 64-68 which apply to impellers configured to deal with air/gas).
Therefore, it would have been obvious to a person having ordinary skill in the art, before the effective filing date of the claimed invention, to modify Li’670 as modified above to include Wang’s teachings as described above, having long blades comprising a sweep angle at the outlet and splitter blades comprising a different sweep angle at the outlet, and having the splitter blades have varied sweep angles, in order to improve pump efficiency (lines 64-68; note that while line 63 discusses hydraulic loss this does not discredit the benefits discussed in lines 64-68 which apply to impellers configured to deal with air/gas).
This modification results in teaching the limitation above.
Conclusion
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.
Contact Information
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Art Golik whose telephone number is (571)272-6211. The examiner can normally be reached Mon-Fri 9:00-5:30.
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/Art Golik/Examiner, Art Unit 3745
/COURTNEY D HEINLE/Supervisory Patent Examiner, Art Unit 3745
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