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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 2/5/2026 has been entered.
Claim Objections
Claim 11 objected to because of the following informalities: “the impeller inlet” should read “the impeller leading edge”. Appropriate correction is required.
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.
Claims 1, 3, 5, and 9-12 is rejected under 35 U.S.C. 103 as being unpatentable over Flynn (4243357) in view of Jonen (US-Pub 2017/0284412).
Regarding claim 1, Flynn discloses an impeller for a gas turbine engine comprising: an impeller hub (36, fig 1) having an impeller leading edge (38, fig 1) and an impeller trailing edge (30, fig 1); and a plurality of bifurcated impeller blades (52, fig 2) arranged on the impeller hub and extending from the impeller leading edge to the impeller trailing edge, each bifurcated impeller blade having a bifurcated pressure side and a bifurcated suction side (all airfoils have a pressure side and suction side); wherein the bifurcated pressure side and the bifurcated suction side of each bifurcated impeller blade separate at a bifurcation point (leading point in air gap 16, fig 2a) and extend to the impeller trailing edge, wherein a reduced flow channel (46, fig 2a) is defined between adjacent bifurcated impeller blades, wherein a blocked zone (16, fig 2a) is defined within each bifurcated impeller blade between the bifurcated pressure side and the bifurcated suction side and extending from the bifurcation point to the impeller trailing edge (fig 2a, the points are bifurcated all the way to the trailing edge), and wherein each of the bifurcated pressure side and the bifurcated suction side extend tangentially from the bifurcation point at different radii of curvature (they both extend from the same point, and any individual line can be defined as a tangent to a radius of curvature as any size can be chosen).
Flynn does not disclose wherein the pressure side and suction side extend to different points at the impeller trailing edge, such that a point where the bifurcated pressure side intersects with the trailing edge and a point where the bifurcated suction side intersects with the trailing edge are separated by a circumferential distance along the trailing edge and the blocked zone is defined between the two points where the bifurcated pressure side and the bifurcated suction side intersect with the impeller trailing edge.
Jonen teaches a radial compressor impeller blade (12, fig 4), wherein the pressure side (9, fig 4), and suction side (8, fig 4) extend to different points along the impeller edge (annotated fig 4 below) , such that a point where the bifurcated pressure side intersects with the trailing edge and a point where the bifurcated suction side intersects with the trailing edge are separated by a circumferential distance along the trailing edge (length of the trailing edge on the annotated fig 4 below) and the blocked zone is defined between the two points where the bifurcated pressure side and the bifurcated suction side intersect with the impeller trailing edge.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the impeller trailing edge disclosed by Flynn by having the pressure side and suction side extend to different points at the impeller trailing edge based on the teachings of Jonen. Doing so would provide a reduction in pressure loss along the trailing edge (par. 0042), as suggested by Jonen.
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Regarding claim 3, Flynn discloses wherein the blocked zone is filled with air (fig 2, the gap is an open air gap).
Regarding claim 5, Flynn discloses wherein the blocked zone is closed along the impeller trailing edge (58, fig 2).
Regarding claim 9, Flynn discloses wherein the bifurcation point is at a position between the impeller leading edge and the impeller trailing edge (fig 2, the bifurcation point is near the midpoint of the impeller).
Regarding claim 10, Flynn discloses wherein each reduced flow channel has a channel inlet (14, fig 1) defined at the impeller leading edge and a channel outlet (16, fig 1) defined at the impeller trailing edge, wherein each outlet is defined circumferentially between a respective bifurcated pressure side of a bifurcated impeller blade and a respective bifurcated suction side of an adjacent bifurcated impeller blade at the impeller trailing edge (the channels are formed between each adjacent blades pressure side and suction side).
Regarding claim 11, Flynn discloses wherein bifurcated impeller blade has a Y-shaped geometry with a stem (fig 2a, the y shape is closed with the stem being the inlet, and then divided in two at the bifurcation point forming a Y shape) of the Y-shape geometry located at the impeller inlet.
Regarding claim 12, Flynn discloses wherein the bifurcated impeller blade comprises a non-bifurcated portion that extends from impeller leading edge to the bifurcation point (at 52, fig 2).
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Flynn as modified by Jonen in claim 1, further in view of Barr (GB 741054).
Regarding claim 4, Flynn as modified by Jonen discloses wherein the blocked zone is defined along the circumferential distance between the point where the bifurcated pressure side intersects with the impeller trailing edge and the point where the bifurcated suction side intersects with the impeller trailing edge.
Flynn does not disclose wherein the blocked zone is open along the impeller trailing edge.
Barr teaches an impeller for a gas turbine with an internal blocked zone (16, fig 1a), wherein the blocked zone is open along the impeller trailing edge (14, 1a).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the impeller blocked zone disclosed by Flynn by having the blocked zone be open along the impeller trailing edge based on the teachings of Barr. Doing so would allow for cooling fluid to be circulated through the impeller (page 1, lines 60-75), as suggested by Barr.
Claims 13 are rejected under 35 U.S.C. 103 as being unpatentable over Flynn in view of Jonen and Drolet (10859096).
Regarding claim 13, Flynn does not disclose a plurality of diffuser elements arranged radially outward from the impeller trailing edge.
Drolet teaches arranging a plurality of diffusor elements (20, 21, fig 1) radially outward from an impeller (17, fig 1) trailing edge.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the impeller disclosed by Flynn by using a plurality of diffusor elements radially outward from the impeller based on the teachings of Drolet. One of ordinary skill in the art would recognize diffusors are commonly used to straighten out the flow of a compressor before injection into a combustor.
Claims 16 and 17 are rejected under 35 U.S.C. 103 as being unpatentable over Drolet (10859096) in view of Jonen and Flynn.
Regarding claim 16, Drolet teaches a gas turbine assembly with a fan (12, fig 1), a combustor section (16, fig 1), a turbine section (18, fig 1) and a compressor section (19, fig 1) with an impeller (17, fig 1) having an impeller hub (main body of 17, fig 1) having an impeller leading edge (side near 14, fig 1), and an impeller trailing edge (side near 20, fig 1)
Drolet does not disclose: a plurality of bifurcated impeller blades arranged on the impeller hub and extending from the impeller leading edge to the impeller trailing edge, each bifurcated impeller blade having a bifurcated pressure side and a bifurcated suction side; wherein the bifurcated pressure side and the bifurcated suction side of each bifurcated impeller blade separate at a bifurcation point and extend to the impeller trailing edge, wherein a reduced flow channel is defined between adjacent bifurcated impeller blades, wherein a blocked zone is defined within each bifurcated impeller blade between the bifurcated pressure side and the bifurcated suction side and extending from the bifurcation point to the impeller trailing edge, and wherein each of the bifurcated pressure side and the bifurcated suction side extend tangentially from the bifurcation point at different radii of curvature, wherein the pressure side and suction side extend to different points at the impeller trailing edge, such that a point where the bifurcated pressure side intersects with the trailing edge and a point where the bifurcated suction side intersects with the trailing edge are separated by a circumferential distance along the trailing edge.
Flynn teaches an impeller for a gas turbine engine comprising: an impeller hub (36, fig 1) having an impeller leading edge (38, fig 1) and an impeller trailing edge (30, fig 1); and a plurality of bifurcated impeller blades (52, fig 2) arranged on the impeller hub and extending from the impeller leading edge to the impeller trailing edge, each bifurcated impeller blade having a bifurcated pressure side and a bifurcated suction side (all airfoils have a pressure side and suction side); wherein the bifurcated pressure side and the bifurcated suction side of each bifurcated impeller blade separate at a bifurcation point (leading point in air gap 16, fig 2a) and extend to the impeller trailing edge, wherein a reduced flow channel (46, fig 2a) is defined between adjacent bifurcated impeller blades, wherein a blocked zone (16, fig 2a) is defined within each bifurcated impeller blade between the bifurcated pressure side and the bifurcated suction side and extending from the bifurcation point to the impeller trailing edge (fig 2a, the points are bifurcated all the way to the trailing edge), and wherein each of the bifurcated pressure side and the bifurcated suction side extend tangentially from the bifurcation point at different radii of curvature (they both extend from the same point, and any individual line can be defined as a tangent to a radius of curvature as any size can be chosen).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the engine of Drolet to use the impeller based on the teachings of Flynn. Doing so would increase the useful range of flow ratios at any pressure ratio (col 1, lines 54-60), as suggested by Flynn.
Jonen teaches a radial compressor impeller blade (12, fig 4), wherein the pressure side (9, fig 4), and suction side (8, fig 4) extend to different points along the impeller edge (annotated fig 4 below) , such that a point where the bifurcated pressure side intersects with the trailing edge and a point where the bifurcated suction side intersects with the trailing edge are separated by a circumferential distance along the trailing edge (length of the trailing edge on the annotated fig 4 below).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the impeller trailing edge disclosed by Drolet as modified by Flynn by having the pressure side and suction side extend to different points at the impeller trailing edge based on the teachings of Jonen. Doing so would provide a reduction in pressure loss along the trailing edge (par. 0042), as suggested by Jonen.
Regarding claim 17, Drolet teaches arranging a plurality of diffusor elements (20, 21, fig 1) radially outward from an impeller (17, fig 1) trailing edge.
Response to Arguments
Applicant's arguments filed 1/16/2026 have been fully considered but they are not persuasive. Applicant argues that the prior art does not disclose the pressure side and suction side intersecting the trailing edge at different points separated by a circumferential distance. Applicants arguments are not persuasive, as it can be seen in fig 4 of Jonen that the intersection points are separated by a circumferential distance.
Conclusion
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/SEAN V MEILLER/Examiner, Art Unit 3741
/DEVON C KRAMER/Supervisory Patent Examiner, Art Unit 3741
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