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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 12/16/2025 has been entered.
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.
Claims 1, 5-9 and 14 are rejected under 35 U.S.C. 102(a)(1) as being clearly anticipated by Lovett et al. (US Patent 5,943,866).
Regarding claim 1, Lovett discloses a gas turbine engine (col. 1, l. 20), comprising:
a compressor section (col. 1, l. 21), a combustion section (col. 1, l. 22), and a turbine section (col. 1, l. 23) in serial flow arrangement (col. 1, l. 20-26), with the combustion section comprising:
a combustion liner (Figure 1, 26a) at least partially defining a combustion chamber (26); and
a gaseous fuel nozzle assembly (28 and 28b) that delivers hydrogen fuel (col. 1, ll. 51-52 describes methane, a hydrogen fuel) to the combustion chamber (Figure 1 shows the gaseous fuel nozzle assembly 28 and 28b delivers fuel to the combustion chamber 26) and comprises a plurality of mixing tubes (30), each of the plurality of mixing tubes comprising:
an air flow passage (38) terminating in a mixing tube outlet (30b) fluidly coupled to the combustion chamber (Figure 1),
a gaseous fuel orifice (40a and 40b) fluidly coupled to the air flow passage (Figure 2), and
a turbulator (42a and 42b) disposed at least partially upstream of the gaseous fuel orifice (Figure 2 shows the upstream end of the turbulators are upstream of the gaseous fuel orifices on the respective turbulator);
wherein a distance between the gaseous fuel orifice and the mixing tube outlet defines a mixing length (X1 and X2), wherein a first mixing tube (upper 30 in figure 1) of the plurality of mixing tubes has a first mixing length (X1) and a second mixing tube (lower 30 in figure 1) of the plurality of mixing tubes has a second mixing length (X2), which is different from the first mixing length (Figure 1 shows the difference as S), and wherein the first mixing tube and the second mixing tube are radially offset (Figure 1 shows the second mixing tube is radially closer to the axial centerline of 18 than the first mixing tube).
Regarding claim 5, Lovett discloses wherein the gaseous fuel orifice is disposed at a surface of the turbulator (Figure 1 shows the gaseous fuel orifices 40a and 40b are on a surface of the respective turbulator 42a and 42b).
Regarding claim 6, Lovett discloses wherein the gaseous fuel orifice is at least partially circumferentially aligned with the turbulator (Figure 1 shows that the gaseous fuel orifices 40a and 40b are on the respective turbulator 42a and 42b, therefore the gaseous fuel orifices are circumferentially aligned with the respective turbulator).
Regarding claim 7, Lovett discloses wherein the turbulator of the first mixing tube of the plurality of mixing tubes is axially offset from the turbulator of the second mixing tube of the plurality of mixing tubes (Figure 1 shows the turbulators 42a and 42b are axially offset by the distance S).
Regarding claim 8, Lovett discloses wherein the first mixing tube includes the turbulator as a first turbulator upstream of the gaseous fuel orifice (Figure 1 shows the first turbulator 42a is upstream of the gaseous fuel orifices 40a), and wherein the first mixing tube includes an additional turbulator axially and circumferentially offset from the turbulator (Figure 1 shows additional turbulator 32 axially offset from both turbulator 42a, and each of these turbulators comprise vanes or spokes, so each vane is circumferentially offset from at least one spoke).
Regarding claim 9, Lovett discloses wherein the first mixing tube includes an additional gaseous fuel orifice (Figure 1 shows multiple gaseous fuel orifices 40a) disposed at least partially downstream of the additional turbulator (Figure 1 shows all of the gaseous fuel orifices 40a are downstream of the additional turbulator 32).
Regarding claim 14, Lovett discloses wherein the mixing tube outlet of the first mixing tube of the plurality of mixing tubes includes a circular, elliptical, or polygonal cross- sectional shape (Figure 1 shows mixing tube outlets 30b are circular).
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 (i.e., changing from AIA to pre-AIA ) 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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 10-11 are rejected under 35 U.S.C. 103 as being unpatentable over Lovett et al. (US Patent 5,943,866).
Regarding claim 10, Lovett, embodiment 1 shown in figure 1, discloses all the essential features of the claimed invention as claimed and described above except wherein the first mixing tube further includes a second additional turbulator axially and circumferentially offset from both the first turbulator and the additional turbulator.
Lovett, embodiment 2 shown in figure 2, teaches wherein the first mixing tube further includes a second additional turbulator (See Annotated figure 2) axially and circumferentially offset from both the first turbulator and the additional turbulator (Annotated figure 2 shows each of the turbulator is axially offset from the others and that each of the turbulators have spokes or vanes circumferentially about an axis that extends left to right in figure 2 through the center of 36, one of each of the spokes/vanes is circumferentially offset from at least one of the spokes/vanes of the other turbulators).
Therefore it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Lovett, embodiment 1 shown in figure 1’s invention to include wherein the first mixing tube further includes a second additional turbulator axially and circumferentially offset from both the first turbulator and the additional turbulator in order to reduce pressure oscillations in the combustion chamber as suggested and taught by Lovett in col. 10, ll. 4-17).
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Regarding claim 11, Lovett embodiment 1 in view of Lovett embodiment 2 teaches the invention as claimed and described above. Lovett embodiment 2 further teaches wherein the first mixing tube includes a second additional gaseous fuel orifice (Figure 2 shows more than 3 fuel orifices 40a on the turbulator) disposed at least partially downstream of the second additional turbulator (Figure 2 shows all the gaseous fuel orifices 40a are downstream of the second additional turbulator).
Claims 12-13 are rejected under 35 U.S.C. 103 as being unpatentable over Lovett et al. (US Patent 5,943,866) in view of Boardman et al. (US 2020/0158343).
Regarding claim 12, Lovett discloses all the essential features of the claimed invention as claimed and described above except wherein the first mixing tube of the plurality of mixing tubes includes a plurality of lobes disposed at least partially upstream of the gaseous fuel orifice.
Boardman teaches wherein the first mixing tube of the plurality of mixing tubes (Figure 5) includes a plurality of lobes (paragraph 56 describes the fuel air mixing passage 125 having lobes) disposed at least partially upstream of the gaseous fuel orifice (Figure 5, fuel orifice 149 is downstream of an initial curve of the fuel air mixing passage 125).
Therefore it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Lovett to include wherein the first mixing tube of the plurality of mixing tubes includes a plurality of lobes disposed at least partially upstream of the gaseous fuel orifice in order to induce turbulence into the flow of air and fuel to promote mixing as suggested and taught in paragraph 56.
Regarding claim 13, Lovett in view of Boardman teach the invention as claimed and described above. Boardman further teaches discloses wherein a lobe of the plurality of lobes includes the gaseous fuel orifice of the first mixing tube of the plurality of mixing tubes (Figure 5 shows the gaseous fuel orifice 149 is downstream of the initial curve of the wall of 125, so is on the lobe when the lobes are included in 125 as described in paragraph 56).
Allowable Subject Matter
Claims 2-4 and 15-16 would be allowable if rewritten to overcome the rejection(s) under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), 2nd paragraph, set forth in this Office action and to include all of the limitations of the base claim and any intervening claims.
The closest prior art is Lovett et al. (US Patent 5,943,866), Saitoh (US 2003/0110774), Wilbraham (US 2009/0320485), York et al. (US 2010/02633383), Helmick et al. (US 2011/0000214), Kahn et al. (US 2013/0086910), Crothers et al. (US 2014/0053528), Baker et al. (US 2016/107914), Stewart et al. (US 2016/0186663), Cai et al. (US 2018/0187894), Natarajan et al. (US 2019/0072279), Vukanti et al. (US 2023/0213191), and Chon (US 2023/0243503). Each of the prior references shows a fuel system with turbulators and gaseous fuel orifices.
The prior art of record fails to anticipate and/or render obvious, either alone or in combination, a first set of mixing tubes and a second set of mixing tubes, with respect to a centerline of the gaseous fuel nozzle assembly, with the first set of mixing tubes being radially closer to the centerline than the second set of mixing tubes, wherein the first set of mixing tubes has the first mixing length, the second set of mixing tubes has the second mixing length, and the first mixing length is longer than the second mixing length as described by claim 2 or a nozzle mixing chamber disposed at and fluidly coupled with the mixing tube outlets of the plurality of mixing tubes, the nozzle mixing chamber having a converging configuration and fluidly coupling the mixing tube outlets of the plurality of mixing tubes with the combustion chamber as described by claim 15.
Claims dependent thereon inherit the allowable subject matter of the respective base claim.
Response to Arguments
Applicant's arguments filed 12/16/2025 have been fully considered but they are not persuasive.
Applicant argues on pages 6-7 of the Remarks that "A nozzle assembly that is configured to deliver hydrogen-containing fuel therefore requires specific structural choices in orifice geometry, mixing length, turbulator placement and shape, and often in materials and thermal management, so as to inhibit flashback and promote stable hydrogen-air premixing" and " a person of ordinary skill in the art would have understood that the geometry and proportions shown in Lovett would in fact be unsuitable for hydrogen operation. The fuel orifice diameters, mixing lengths, and relative spacing between the orifice and outlet are optimized for hydrocarbon fuels of substantially higher density and lower diffusivity. When applied to hydrogen, such a configuration would increase the likelihood of premature ignition, incomplete premixing, and heightened risk of flashback into the mixing tubes". Applicant appears to be arguing that the claim requires a nozzle assembly that can convey hydrogen fuel in the most optimal way possible. However, this is not what is claimed. The claim is silent on "hydrogen operation", merely stating that the assembly delivers hydrogen fuel, with no further description of what percentage of the fuel is comprised of hydrogen. For example methane is a fuel that contains hydrogen, but is not made entirely of hydrogen. Applicant's description of an optimal pure hydrogen system is therefore moot and this argument is not persuasive.
Applicant argues on page 7 of the Remarks that "The Office Action identifies no disclosure in Lovett that teaches hydrogen configuration and provides no evidentiary support for the assertion that Lovett's hydrocarbon system would even be capable of delivering hydrogen fuel, much less one that does deliver “hydrogen fuel to the combustion chamber”, as recited in amended claim 1.” As described above, Lovett clearly teaches delivering methane, a hydrogen fuel, to the combustion chamber. Therefore this argument is not persuasive.
Applicant argues on pages 7-8 of the Remarks that "A person of ordinary skill in the art would have understood that hydrogen's distinct diffusivity, flame speed, and ignition behavior demand precise geometric and material modifications that Lovett neither teaches nor suggests" and "Applicant's specification teaches nozzle assemblies designed to handle hydrogen- containing fuel by, for example, controlling air fuel mixing through defined mixing lengths and turbulator arrangements that address hydrogen's high flame speed and flashback tendencies. These are structural configurations directed to hydrogen operation, not statements of intended use. Lovett does not disclose or suggest these configurations as arranged in claim 1". None of the specifics described within the specification as cited are claimed, so this point is moot. Additionally, as described above, the claims do not require pure hydrogen, but a hydrogen fuel with no further description of what percentage of the fuel is comprised of hydrogen. Lovett teaches methane, a hydrogen fuel. Therefore this argument is not persuasive.
Applicant argues on page 8 of the Remarks that "the combustion characteristics of hydrogen differ fundamentally from those of hydrocarbons, requiring extensive redesign of nozzle geometry, fuel-air ratio control, and cooling strategy". As described above, the claims do not require pure hydrogen, but a hydrogen fuel with no further description of what percentage of the fuel is comprised of hydrogen. Lovett teaches methane, a hydrogen fuel. Therefore this argument is not persuasive.
Conclusion
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/KATHERYN A MALATEK/ Primary Examiner, Art Unit 3741