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 § 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) 1-5 and 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over Bagchi (US 20170299183 A1) in view of Nguyen (US 8197249 B1).
Regarding claim 1
Bagchi discloses an injection method (Fig 5), for an injection device (burner 32, Para 0025 top) in a combustion chamber (a combustion chamber 15, Para 0022 middle) of an aircraft turbine engine (Fig 1, Abstract), said injection device (32) comprising a tubular internal channel (tubular internal channel enclosing swirl 49 and fuel burner 42, annotated in Fig 5) surrounded by an external annular channel (external annular channel enclosing air atomizer 43, annotated in Fig 5), said channels (internal and external channels) leading into said combustion chamber (15) of said aircraft turbine engine (Fig 1), the method comprising:
an injection of a gaseous fuel/air pre-mixed mixture (air 49 mixes with fuel 47 to form air/fuel mixture immediately right outside of 47 but still within the internal channel, annotated in Fig 5, this fuel/air mixture creates the rich zone 33, Para 0029) having a greater fuel richness level than the stoichiometric amount (zone 33 is a fuel rich zone, indicating that the fuel richness level is greater than stoichiometric amount) into said tubular internal channel (fuel/air pre-mixed mixture is still within the tubular internal chamber prior to exiting at the lip of the internal chamber to create rich zone 33 in Fig 5) and
an injection of non-mixed air (non-mixed compressed air flowing through air supplies 51, 52, 53, Para 0032) into said external annular channel (external channel encloses the air supplies 51-53), producing at an outlet of said tubular internal channel, after ignition of said mixture at the outlet of said tubular internal channel, a first flame front (fuel/air pre-mixed mixture from internal tubular channel ignited with the non-mixed air 51, 52, 53 to form a first flame front being a fuel rich zone 33, Para 0026) resulting from rich combustion, external to said tubular internal channel (first flame front 33 extends outward from internal channel in Fig 5) and attached to a lip at the outlet of the internal channel (first flame front 33 is right at the lip of the outlet of internal channel, interpreted to be attached to the lip, annotated in Fig 5),
said first flame front (33) being surrounded by a second flame front (second flame front being a lean zone 39 surrounding the rich zone first flame front 33, Para 0004 bottom) resulting from a lean combustion with the air exiting said external annular channel (lean zone 39 having lean combustion with air flowing through swirler element 56 of external channel 43, Para 0031) and
wherein a downstream end of said tubular internal channel (lip of internal channel, annotated in Fig 5) being arranged upstream relative to a downstream end of the external annular channel (end 57 interpreted to be the downstream end of the external channel), said downstream end of the external annular channel being arranged at a distance r from the downstream end of the tubular internal channel in the downstream direction (distance r annotated in Fig 5, along the downstream or gas flow direction),
the injection of air at the external annular channel (air injected through swirl element 56 of the external channel in Fig 5) quickly dilutes (supplying air and fuel via the main fuel atomizer 43 through swirl element 56, a lean zone 39 is created, Para 0027 bottom, this indicates that the air through element 56 dilutes the rich zone 33 into lean zone 39) and confines the burned gases resulting from the first flame front (first flame front is confined in rich zone 33, Para 0029).
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Bagchi is silent on the gaseous fuel/air mixture includes a hydrogen/air mixture having a greater hydrogen richness level, and
wherein an air flow rate in the external annular channel is chosen such that an overall richness level at the outlet of the injection device is set between 0.15 and 0.5 depending on the operating points of the turbine engine.
However, Nguyen teaches an injection method for a gas turbine engine (burner for an aircraft gas turbine engine, Col 4 lines 14-18) to inject a gaseous fuel/air mixture that includes a hydrogen/air mixture (burner capable of operating on a variety of gaseous fuels, including hydrogen-air mixtures, Col 3 lines 50-55) having a greater hydrogen richness level (FIG. 4 shows three photographs of the burner operating on hydrogen-air mixtures at three equivalence ratios ranging from fuel-lean to fuel-rich, Col 5 lines 62-65, where fuel-lean is Fig. 4a with equivalence ratio 0.6 and fuel-rich is Fig 4c with equivalence ratio 3.2), and
wherein an air flow rate is chosen (Fig 6 shows a design that permits an overall air flowrate of about 1.33 lbm/s at 800 F and 280 psia inlet pressure with an equivalence ratio of 0.30, Col 6 lines 17-23) such that an overall richness level of the injection device is set between 0.15 and 0.5 (equivalence ratio of 0.30 which is between 0.15 and 0.5) depending on the operating points of the turbine engine.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to use a gaseous hydrogen/air mixture, taught by Nguyen, as a fuel for the injection method in Bagchi, because a hydrogen fueled combustor is known to produce ultra-low emission for aircraft engine (col 4 lines 14-15), and
to choose an air flow rate in the external annular channel in Bagchi, such that an overall richness level at the outlet of the injection device of Baghi, is set between 0.15 and 0.5 depending on the operating points of the turbine engine, as suggested and taught by Nguyen, because by choosing a specific air flow rate, the resulting overall richness level of the injection device can produce a flame that has very little NOx emission (Col 6 lines 27-39).
Regarding claim 2
Bagchi in view of Nguyen discloses the injection method according to claim 1.
Bagchi in view of Nguyen further discloses wherein said gaseous pre-mixed hydrogen air mixture (Nguyen teaches a gaseous hydrogen air mixture, Col 3 lines 50-55) has a hydrogen richness level that is greater than 2 (the instant specification Para 0045 defines:
a hydrogen richness level = a ratio
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, for example, a hydrogen richness level greater than 2 means a ratio of
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,
Bagchi, Para 0041, however defines a fuel richness level, i.e. equivalence ratio, to be an inverse of the instant specification, such that the combination of Bagchi in view of Nguyen defines a fuel richness level = a ratio
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instead:
with the equivalence ratio of 1, there is a stoichiometric ratio, same air masses to fuel masses,
below 1 to 0 the result is a rich combustion, i.e. less air masses per fuel masses,
while above 1 a lean combustion is obtained, i.e. more air masses per fuel masses;
Bagchi in Fig 14 shows the rich flame front 33 having an equivalence ratio of about 0.5 at 10% Thrust which means that 0.5 =
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, in which according to the definition of the instant specification would be the inverse,
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= 2).
Regarding claim 3
Bagchi in view of Nguyen discloses the injection method according to claim 1.
Bagchi in view of Nguyen further discloses wherein said gaseous pre-mixed hydrogen/air mixture (Nguyen teaches a gaseous hydrogen air mixture, Col 3 lines 50-55) has a hydrogen richness level that is greater than or equal to 4 (Nguyen teaches a hydrogen-air mixture with equivalence ratio up to 5.0, Col 3 lines 62-65).
Regarding claim 5
Bagchi in view of Nguyen discloses the injection method according to claim 1.
Bagchi in view of Nguyen further discloses wherein the injection of the gaseous pre-mixed hydrogen/air mixture (Nguyen teaches a gaseous hydrogen air mixture, Col 3 lines 50-55) and the device (Bagchi discloses device burner 32, Fig 5) are configured to create, at the outlet of the internal channel (outlet of internal channel annotated in Fig 5 above), said first flame front resulting from a rich combustion of said mixture (fuel rich zone 33, Para 0026), and to attach it to said lip of the internal channel after ignition of said mixture (first flame front 33 is immediately right at the lip of the internal channel, interpreted to be attached to the lip, annotated in Fig 5 above).
Regarding claim 7
Bagchi in view of Nguyen discloses the injection method according to claim 5.
Bagchi in view of Nguyen further discloses wherein the gaseous-hydrogen richness of the pre-mixed hydrogen/air mixture is chosen so that the first flame front is laminar (Bagchi discloses the first flame front 33 and second flame front 39 are continuous within the combustion chamber in Fig 4, thus this continuous combustion is interpreted to be a laminar frame front) and has a Lewis number greater than 1, limiting diffusive-thermal instabilities (Lewis number by definition is the ratio of thermal diffusivity and mass diffusivity. Lewis number is used to characterize fluid flows where there is simultaneous heat and mass transfer, https://www.thermal-engineering.org/what-is-lewis-number-definition/
Since the combination of Bagchi in view of Nguyen discloses a gaseous hydrogen air mixture, Nguyen in Col 3 lines 50-55, where the mixture is chosen to have a fuel rich first flame front 33 and fuel lean second flame front 39, disclosed by Bagchi Para 0026, 0027, which are the same or similar to the claim gaseous hydrogen-air mixture, the first flame front and the second flame front,
Thus, the first flame front in Bagchi in view of Nguyen would have the same characteristic as the claim first flame front of having a Lewis number greater than 1, limiting diffusive-thermal instabilities).
Claim(s) 6 is/are rejected under 35 U.S.C. 103 as being unpatentable over Bagchi in view of Nguyen, as applied to claim 5 above, and further in view of Mina (US 20100089066 A1).
Regarding claim 6
Bagchi in view of Nguyen discloses the injection method according to claim 5.
Bagchi in view of Nguyen further discloses the gaseous-hydrogen richness of the pre-mixed hydrogen/air mixture (Nguyen teaches a gaseous hydrogen air mixture, Col 3 lines 50-55) is chosen so that said rich combustion is carried out with a flame front (Bagchi discloses a rich combustion flame front zone 33, Para 0026, Fig 5).
Bagchi in view of Nguyen is silent on the flame front having a temperature of less than 1800 K.
However, Mina teaches to use a gaseous-hydrogen fuel (a gaseous fuel such as hydrogen, Para 0066, Fig 1) a flame front temperature of less than 1800 K (Fig 9 shows that the desired flame temperature is 1600 K, Para 0117, where NOx emission ppmv remains at a lower level compared to higher temperature at 1850 K).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to maintain the flame front in Bagchi in view of Nguyen, to be at a temperature of less than 1800 K, as suggested and taught by Mina, to minimize production of NOx emission.
Claim(s) 8 and 10 is/are rejected under 35 U.S.C. 103 as being unpatentable over Bagchi in view of Nguyen, as applied to claim 5 above, and further in view of Quigg (US 3826078 A).
Regarding claim 8
Bagchi in view of Nguyen discloses the injection method according to claim 5.
Bagchi in view of Nguyen further discloses wherein the mixture (Nguyen teaches a gaseous hydrogen air mixture, Col 3 lines 50-55) burned in the first flame front being a fuel rich zone (Bagchi discloses a first flame front being a fuel rich zone 33, Para 0026, Fig 5) and the second flame front which is a lean zone (a lean zone 39, Para 0027) by the supply of air from the external annular channel (air through swirl element 56 of the external channel).
Bagchi in view of Nguyen is silent on the first fuel rich flame front generates residual gases burned in the second lean zone flame front which is stabilized.
However, Quigg teaches to have a first fuel rich flame front (primary combustion zone operated fuel rich with equivalence ratio greater than stoichiometric, col 14 lines 49-55) that generates residual gases burned in the second lean flame front (second zone is operated fuel-lean with any unburned fuel entering the second zone from the primary zone, where the equivalence ratio of the second zone is less than stoichiometric, to obtain low NOx and CO emission, Col 14 lines 54-63;
this indicates that the first fuel rich flame front generates unburn fuel, i.e. residual gases that get burned in the second fuel-lean flame front).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to operate the injection device in Bagchi in view of Nguyen to have the first fuel rich flame front generates residual gases burned in the second lean zone flame front which is stabilized, as suggested and taught by Quigg, because this method reduces production of NOx and CO emissions.
Regarding claim 10
Bagchi in view of Nguyen and Quigg discloses the injection method according to claim 8.
Bagchi further discloses wherein the air injected by the annular external channel (air injected through swirl element 56 of external channel, annotated in Fig 5 above) is rotated by an annular swirler (swirler element 56, Para 0031 top).
Claim(s) 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Bagchi in view of Nguyen and Quigg, as applied to claim 8 above, and further in view of Mina.
Regarding claim 9
Bagchi in view of Nguyen and Quigg discloses the injection method according to claim 8.
Bagchi in view of Nguyen and Quigg further discloses the second flame front is a fuel-lean zone (a lean zone 39, Para 0027).
Bagchi in view of Nguyen and Quigg is silent on the second flame front having a temperature of less than 1800 K through adaptation of its richness.
However, Mina teaches to use a gaseous-hydrogen fuel (a gaseous fuel such as hydrogen, Para 0066, Fig 1) having a flame front temperature of less than 1800 K through adaptation of its richness (Fig 9 shows that the desired flame temperature is 1600 K, Para 0117, where NOx emission ppmv remains at a lower level compared to higher temperature at 1850 K, meaning the desired flame temperature adapts to the NOx emission level).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to maintain the second flame front in Bagchi in view of Nguyen and Quigg, to be at a temperature of less than 1800 K, as suggested and taught by Mina, to minimize production of NOx emission.
Response to Arguments
i. Applicant's arguments, page 5 filed 12/30/2025 have been fully considered but they are not persuasive.
Applicant argues that Bagchi does not teach a fuel/air mixture, which is not persuasive. Since the fuel is injected at 47 which is still within the tubular internal channel, this fuel immediately mixes with air from swirl element 49 prior to exiting the tubular internal channel to form the rich fuel zone 33 in Fig 5.
ii. Applicant’s arguments with respect to claim(s) 1 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. Applicant argues that the air quantity supply is 35 vol % to 75 vol % in the intermediate admixing zone does not exist. This argument is moot because the claim ratio is now interpreted to be an equivalence ratio that is taught by Nguyen to be 0.30 which is between 0.15 and 0.5
iii. Applicant’s argument, page 6, that the injection device of Bagchi is completely different from the device of Nguyen.
This is not persuasive because both Bagchi and Nguyen teaches delivering fuel to a combustor of a gas turbine engine, which are analogous arts. Additionally, Nguyen teaches how to control the amount of fuel and air mixing to achieve optimal combustion, which is independent of the injection device. Therefore, one of ordinary skill in the art would have found it obvious to apply how much fuel and air to mix and deliver to the combustor of the gas turbine engine to achieve desired performance while minimizing NOx emission.
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 nonprovisional extension fee (37 CFR 1.17(a)) 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 mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Thuyhang Nguyen whose telephone number is (571)272-5317. The examiner can normally be reached Monday-Friday 8am-5pm EST.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Edward F. Landrum can be reached at (571) 272-5567. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/Thuyhang N Nguyen/Examiner, Art Unit 3761
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