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 .
Claim Rejections - 35 USC § 102
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 9 is rejected under 35 U.S.C. 102(a)(1) as being anticipated by Correia et al., US 2016/0045923 A1.
Regarding claim 9, Correia teaches a low pressure (LP) turbine 36 of a gas turbine engine 10, which reads on the claimed “low-pressure turbine.” See Correia Fig. 1, [0041].
The low-pressure turbine 36 comprises a system for cooling it, which reads on the claimed “system.” See Correia Fig. 2, [0003], [0055]. The system comprises a bypass conduit 82 (reading on the “utility tube”) for conveying a cooling air flow fluid 80 (the “cooling air flow”) taken from a compartment of high-pressure compressor 26 (the “high-pressure compressor compartment”) to a compartment of low-pressure turbine 36 (the “low-pressure turbine compartment”), as claimed. Id. at Fig. 18, [0003], [0049], [0052].
The bypass conduit 82 includes an inertial separator 250’ for filtering cooling air flow. See Correia Figs. 18, 19, [0098], [0110]. The inertial separator 250’ reads on the “device for filtering cooling air.” The inertial separator 250’ is positioned between an “upstream tube” connected to the high-pressure compressor 26 (the tube that feeds air from the high-pressure compressor 26 to the bypass conduit 82) and an inducer inlet 302 (the “downstream tube”) connected to the compartment of the low-pressure turbine 36 (as the inducer inlet 302 supplies cooling fluid, and the low pressure turbine 36 requires cooling fluid), as claimed. Id. at [0003], [0096].
The inertial separator 250’ comprises a body 252’ (the “duct”) with a geometry configured to centrifuge the cooling air passing through the body 252’, as claimed. See Correia Fig. 19, [0098], [0110]. The body 252’ has multiple particle outlets 262’ (the “openings”) dimensioned to allow separation of solid particles contained in the cooling air flow being centrifuged, as claimed. Id. Also, the body 252’ has a circular helix shape inscribed on a cylinder of revolution with an axis of revolution, as claimed, as seen in Figs. 18 and 19.
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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.
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.
Claims 1–7 are rejected under 35 U.S.C. 103 as being unpatentable over Correia et al., US 2016/0045923 A1 in view of GB 1,014,268 A (“GB-268”)1.
Regarding claim 1, Correia teaches a low pressure (LP) turbine 36 of a gas turbine engine 10, which reads on the claimed “low-pressure turbine of a turbomachine.” See Correia Fig. 1, [0041]. The LP turbine 36 comprises a particle separator 86 for filtering a cooling fluid air flow. Id. at Fig. 2, [0055], [0003]. The particle separator 86 reads on the “device for filtering a cooling air flow.”
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Correia differs from claim 1 because it is silent as to the particle separator 86 having the same structure as the “duct having a geometry configured to centrifuge said cooling air flow” as claimed. But the particle separator 86 may be a centrifugal separator. See Correia [0054]. A purpose of the particle separator 86 is to separate particles, such as dirt, dust and debris, from a cooling air flow stream before the cooling air is supplied to a hot part of the engine 10. Id. The debris that has been separated can be dumped from the engine 10 or can be collected in a particle collector. Id. at [0055].
With this in mind, GB-268 teaches a centrifugal separator for separating dust particles from gases. See GB-268 Fig. 1, p. 1, ll. 10–18. The centrifugal separator comprises a helically bent tube 2 with a geometry configured to centrifuge the gas moving through the tube 2. Id. at Fig. 1, p. 2, ll. 87–99. The tube 2 reads on the “duct having a geometry configured to centrifuge said cooling air flow passing through said duct.” The tube 2 has slits 3 (the “openings”) distributed over an entire length of the tube 2 and dimensioned to allow separation of solid, dust particles contained in the gas flow being centrifuged, as claimed. Id. The tube 2 has a circular helix shape inscribed on a cylinder of revolution with an axis of rotation, as seen in Fig. 1, as claimed. The dust particles that are ejected through the slits 3 are collected in dust collecting container 1 and emerge from the container 1 in the direction of arrow 6. Id. The cleaned gas exits the tube 2 in the direction of arrow 5. Id.
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The centrifugal separator of GB-268 is beneficial because it can separate particles down to very small grain sizes. See GB-268 p. 1, ll. 55–66.
It would have been obvious to use the centrifugal separator of GB-268 as the particle separator 86 of Correia to improve the ability of the particle separator 86 to remove particles down to very small grain sizes. It also would have been obvious o use the centrifugal separator of GB-268 as the particle separator 86 of Correia because this would merely represent the simple substitution of one known element for another to yield predictable results. See MPEP 2143, subsection I, B.
Regarding claim 2, GB-268 teaches that the tube 2 (the “duct”) is a tube with a circular cross-section, as seen in Fig. 1, as claimed.
Regarding claim 3, GB-268 teaches that the slits 3 (the “openings”) are provided on a radially outer portion of the tube 2 with respect to the axis of revolution, as claimed. See GB-268 Fig. 1, p. 2, ll. 83–86.
Regarding claim 4, GB-268 teaches that the centrifugal separator comprises the dust collecting container 1 for storing solid dust particles separated from the gas. See GB-268 Fig. 1, p. 2, ll. 87–99. The dust collecting container 1 reads on the “storage tank for storing solid particles separated from said cooling air flow.”
Regarding claim 5, GB-268 teaches that the container 1 (the “storage tank”) has an “air-porous shell,” as claimed, because the structure of the container 1 is a “shell,” which is air-porous due to the opening in the bottom. See GB-268 Fig. 1, p. 2, ll. 87–99. Note that something can be considered “porous” while having a single hole or void.
Regarding claim 6, Correia teaches that the particle separator 86 (replaced with the centrifugal separator of GB-268, the “device for filtering a cooling air flow”) is enclosed in a “protective enclosure” which is the structure of the engine 10 surrounding the particle separator 86, seen in Fig. 18 of Correia which illustrates structure of the engine 10 surrounding separator 250.
Regarding claim 7, Correia teaches that the portion of the engine 10 surrounding the particle separator 86 (the “protective cover”) comprises “openings allowing the interior of the protective enclosure to be placed in fluid communication with the exterior of the protective enclosure,” as claimed, which are the opening at the inlet of bypass cooling circuit 76 (supplying air to the separator) and the opening of outlet 304 for supplying cleaned air to the hot part of the engine 10. See Correia Fig. 18, [0096], [0125].
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Correia et al., US 2016/0045923 A1 in view of GB 1,014,268 A (“GB-268”) and in further view of Renggli et al., US 2016/0003094 A1.
Regarding claim 8, Correia as modified teaches the limitations of claim 6, as explained above.
Correia differs from claim 8 because it is silent as to the “protective enclosure” having an access hatch positioned facing an opening provided at the external shell.
But the “protective enclosure” is part of the body of a gas turbine engine. With this in mind, Renggli teaches a cowl 130 for a gas turbine engine comprising an access cover 142 facing an opening provided in the cowl 130, which allows access to the interior the cowl 130. See Renggli Fig. 3, [0029]. It would have been obvious to provide an access cover in the “protective enclosure” of Correia to allow access to the interior of the body of the gas turbine engine.
Response to Arguments
35 U.S.C. 112(b) Rejections
The Examiner withdraws the previous 35 U.S.C. 112(b) rejections in light of the amendments.
35 U.S.C. 103 Rejections
Claims 1–8
Applicant’s arguments with respect to claims 1–8 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Claim 9
The Applicant has failed to argue why claim 9 is specifically patentable over Correia et al., US 2016/0045923 A1. See Applicant Rem. filed August 19, 2025 (“Applicant Rem.”) 4–7. The Examiner maintains that claim 9 is unpatentable over Correia for the reasons explained above.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Kulakovskij, US 11,420,145 B2, which illustrates a filter for separating debris from air with a helical flow channel 1 with openings provided along the entire length of the flow channel, with a similar structure as illustrated in Fig. 2 of the Applicant’s disclosure.
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Any inquiry concerning this communication or earlier communications from the examiner should be directed to T. BENNETT MCKENZIE whose telephone number is (571)270-5327. The examiner can normally be reached Mon-Thurs 7:30AM-6:00PM.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Jennifer Dieterle can be reached at 571-270-7872. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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T. BENNETT MCKENZIE
Primary Examiner
Art Unit 1776
/T. BENNETT MCKENZIE/Primary Examiner, Art Unit 1776
1 GB-268 is in the record as the 6-page Foreign Reference filed August 12, 2025.
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