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 § 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) 11, 14, 19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Chalaud (2015/0337734) in view of Futa Jr et al (2010/0263634) and either Davies (2931381) or Williams et al (3275061). Chalaud teaches (11) A fuel control system comprising: a fuel source [upstream of 108]; a combustion chamber 2; a main circuit 100 configured to supply fuel from the fuel source to the combustion chamber, the main circuit comprising a first centrifugal pump 101a comprising a first intake port connected to the fuel source, and a first discharge port S; and a second centrifugal pump 110 comprising a second intake port connected to the first discharge port S, and a second discharge port E, 68 connected to the combustion chamber; a secondary circuit [from E to 51, 54, 50] connecting the second discharge port E to the first discharge port S, and comprising a variable geometry unit 54 configured to be actuated by a pressure of fuel circulating within the secondary circuit; wherein the first centrifugal pump and the second centrifugal pump are configured such that, in operation, whatever a first speed of the first centrifugal pump and a second speed of the second centrifugal pump, the first centrifugal pump 101a delivers a first fuel flow rate that is smaller than a second fuel flow rate delivered by the second centrifugal pump 110 [by flow continuity, noting the second pump has additional recirculating flow from E to S], and the first centrifugal pump 101a introduces a first increase in a pressure of fuel circulating in the main circuit which is less than a second increase in the pressure of fuel circulating in the main circuit that is introduced by the second centrifugal pump 101, 111a, 111b – note that the second centrifugal pump has multiple pressurizing stages 111a, 111b [greater pressure ratio] vs a single pressurizing stage for 101a [lesser pressure ratio]. Alternately, it is well known in the art to e.g. use similar pressure ratios across each of centrifugal pump stages 101a, 111a, 111b and thus have less pressure increase from a single stage 101a than that of multiple stages 111a, 111n [of 110]. Also, a single stage of compression will typically have less pressure increase than a plurality of stages of compression as each stage of compression provides its own increase of pressure with Chalaud teaching in ¶ 0061 that using multiple stages of compression stage to produce an overall pressure increase is more efficient than using a single compressor stage and that the pressure increase is proportional to the square of the radius of the pump; in other words, since each pump stage 101a, 111a, 111b appears to be similar dimension, then the pressure difference of each stage is comparable or obvious to do so based on the workable ranges in the art. To the point not already inherent, it would have been obvious to make the first centrifugal pump introduce a first increase in a pressure of fuel circulating in the main circuit which is less than a second increase in the pressure of fuel circulating in the main circuit that is introduced by the second centrifugal pump, as an obvious matter of using similarly dimensioned pressure stages allowing for more pressure boost with more pressure stages or as an obvious matter of using the workable ranges in the art. Chalaud also teaches (14) a restriction 64 [metering valves have restrictions to meter the flow] arranged between the second discharge port and the combustion chamber 2, and configured to control a rate of a fuel flow circulating from the second discharge port to the combustion chamber. (19) An aircraft engine comprising the fuel control system of claim 1.
For claim 11, Chalaud does not teach a centrifugal booster pump interposed between the fuel source and the main circuit and configured to pressurize the main circuit and the secondary circuit. Futa Jr et al is applied as a teaching reference that shows that using an additional non-illustrated booster pump [tank pump, which is also a low pressure pump] interposed between the fuel source [fuel in 102] and the main circuit 118 and configured to pressurize the main circuit 118-1 and the secondary circuit 118-2 [see ¶ 0017] and further teaches centrifugal pumps are used for low pressures, e.g. pump 104. Davies teaches the centrifugal booster pump [tank pump] 8 or 2 interposed between the fuel source [fuel in 7 or fuel in 1] and the main circuit 3 and configured to pressurize the main circuit 3, 4. Williams et al teaching a centrifugal booster pump [tank pump] 155, 154 interposed between the fuel source [fuel in 150] and the main circuit and configured to pressurize the main circuit [e.g. to 110]. It would have been obvious to one of ordinary skill in the art to employ a centrifugal booster pump interposed between the fuel source and the main circuit and configured to pressurize the main circuit and the secondary circuit, as taught by Futa Jr et al as using a low pressure tank pump is well known in the art and utilized for enhancing fuel flow from the fuel source, with either Davies or Williams et al, teaching that making these low pressure pumps centrifugal pumps are entirely well known and utilized for facilitating the fuel flow from the fuel source.
Claim(s) 11, 14, 19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Futa Jr et al (2010/0263634) in view of Chalaud (2015/0337734) and optionally Davis (4,205,945) and either Davies (2931381) or Williams et al (3275061). Futa Jr et al teach (11) A fuel control system comprising: a fuel source 102; a combustion chamber 116-1; a main circuit configured to supply fuel from the fuel source to the combustion chamber, the main circuit 118-1 comprising a first centrifugal pump 104 comprising a first intake port connected to the fuel source 102, and a first discharge port; and a second centrifugal pump 106 comprising a second intake port connected to the first discharge port, and a second discharge port [118-1 leadline] connected to the combustion chamber 116-1; a secondary circuit 118-2 connecting the second discharge port [118-1 leadline] to the first discharge port [at junction of 134, 122], and comprising a variable geometry unit 116-3 configured to be actuated by a pressure of fuel circulating within the secondary circuit 118-2; a booster pump [tank pump, not illustrated, ¶ 0017] interposed between the fuel source [fuel in the tank 102] and the main circuit 118-1 and configured to pressurize the main circuit 118-1 and the secondary circuit 118-2; wherein the first centrifugal pump and the second centrifugal pump are configured such that, in operation, whatever a first speed of the first centrifugal pump and a second speed of the second centrifugal pump, the first centrifugal pump delivers a first fuel flow rate that is smaller than a second fuel flow rate delivered by the second centrifugal pump [by flow continuity, as flow through second centrifugal pump 105 also provides additional flow to secondary circuit 118-2 and to bypass 122], and the first centrifugal pump 104 introduces a first increase in a pressure of fuel circulating in the main circuit 118-1; and a second increase in the pressure of fuel circulating in the main circuit that is introduced by the second centrifugal pump 106.
(14) a restriction 108 [metering valves restrict flow] arranged between the second discharge port 118-1 and the combustion chamber 116-1, and configured to control a rate of a fuel flow circulating from the second discharge port 118-1 to the combustion chamber 116-1. (16) wherein the first centrifugal pump 104 comprises a first rotor portion and a first stator portion, and the second centrifugal pump 106 comprises a second rotor portion and a second stator portion, the first rotor portion being integral in rotation with the second rotor portion [both 104, 106 may be driven by a electric motor], (18) an electric motor [both 104, 106 may be driven by a electric motor, see end of paragraph 0017] comprising a rotating element connected to at least one of the first rotor portion and the second rotor portion in order to drive the first rotor portion and the second rotor portion in rotation relative to the first stator portion and the second stator portion. (19) An aircraft engine comprising the fuel control system of claim 1.
For claim 11, Futa Jr et al was already applied to teach an additional non-illustrated booster pump [tank pump, which is also a low pressure pump] interposed between the fuel source [fuel in 102] and the main circuit 118 and configured to pressurize the main circuit 118-1 and the secondary circuit 118-2 [see ¶ 0017] and further teaches centrifugal pumps are used for low pressures, e.g. pump 104. Futa Jr et al do not specifically teach a centrifugal booster pump. Davies teaches the centrifugal booster pump [tank pump] 8 or 2 interposed between the fuel source [fuel in 7 or fuel in 1] and the main circuit 3 and configured to pressurize the main circuit 3, 4. Williams et al teaching a centrifugal booster pump [tank pump] 155, 154 interposed between the fuel source [fuel in 150] and the main circuit and configured to pressurize the main circuit [e.g. to 110]. It would have been obvious to one of ordinary skill in the art to employ a centrifugal booster pump interposed between the fuel source and the main circuit and configured to pressurize the main circuit and the secondary circuit, as taught by either Davies or Williams et al, for the low pressure tank pumps centrifugal pumps is entirely well known and utilized for facilitating the fuel flow from the fuel source. For claim 11, Futa Jr et al do not teach the first centrifugal pump introduces a first increase in a pressure of fuel circulating in the main circuit which is less than a second increase in the pressure of fuel circulating in the main circuit that is introduced by the second centrifugal pump. Futa Jr et al do teach the first centrifugal pump is a low pressure boost pump and thus less powerful than the high pressure pump 106 [¶ 0017]. Note that there are only three options for this pressure comparison: less, equal or greater. Chalaud et al teach the first centrifugal pump 101a introduces a first increase in a pressure of fuel circulating in the main circuit which is less than a second increase in the pressure of fuel circulating in the main circuit that is introduced by the second centrifugal pump 101, 111a, 111b – note that the second centrifugal pump has multiple pressurizing stages 111a, 111b [greater pressure ratio] vs a single pressurizing stage for 101a [lesser pressure ratio]. Alternately, it is well known in the art to e.g. use similar pressure ratios across each of centrifugal pump stages 101a, 111a, 111b and thus have less pressure increase from a single stage 101a than that of multiple stages 111a, 111n [of 110]. Also, a single stage of compression will typically have less pressure increase than a plurality of stages of compression as each stage of compression provides its own increase of pressure with Chalaud teaching in ¶ 0061 that using multiple stages of compression stage to produce an overall pressure increase is more efficient than using a single compressor stage and that the pressure increase is proportional to the square of the radius of the pump; in other words, since each pump stage 101a, 111a, 111b appears to be similar dimension, then the pressure difference of each stage is comparable or obvious to do so based on the workable ranges in the art. Davis also teaches the first centrifugal pump 12 introduce a first increase in a pressure of fuel circulating in the main circuit 34 which is less than a second increase in the pressure of fuel circulating in the main circuit that is introduced by the second centrifugal pump 16 -- note that the second pump of Davis 16 is much larger than the first pump 12 in radius and Chalaud teaches the pressure increase is proportional to the square of the radius of the pump. It would have been obvious to make the first centrifugal pump introduce a first increase in a pressure of fuel circulating in the main circuit which is less than a second increase in the pressure of fuel circulating in the main circuit that is introduced by the second centrifugal pump of Futa Jr et al, as taught by Chalaud et al, as an obvious matter of using the workable ranges in the art of pressurization from the first and second centrifugal pumps and so that the second centrifugal pump provide more of the pressurization. Alternately, when applying the combination of Chalaud et al and Davis, it would have been obvious to make the first centrifugal pump introduce a first increase in a pressure of fuel circulating in the main circuit which is less than a second increase in the pressure of fuel circulating in the main circuit that is introduced by the second centrifugal pump of Futa Jr et al, as taught by Chalaud et al and Davis, as the boost pump of Davis is much is smaller in radius than the high pressure pump, and Chalaud teaches the pressure increase is proportional to the square of the radius of the pump, and thus less pressurization from the boost pump, in order to utilize typical sizing / pressurization utilized in the art.
Claim(s) 16 is/are rejected under 35 U.S.C. 103 as being unpatentable over any of the above prior art, as applied above to claim 11, and further in view of either Crawley (3,784,329) or Marshall et al (2,785,634). The prior art do not necessarily teach (16) wherein the first centrifugal pump comprises a first rotor portion and a first stator portion, and the second centrifugal pump comprises a second rotor portion and a second stator portion, the first rotor portion being integral in rotation with the second rotor portion, and the second stator portion being mounted fixedly on the first stator portion. Crawley teaches (16) wherein the first centrifugal pump comprises a first rotor portion 10 and a first stator portion [surrounding 10], and the second centrifugal pump comprises a second rotor portion 11 and a second stator portion [surrounding 11], the first rotor portion being integral in rotation 12 with the second rotor portion, and the second stator portion being mounted fixedly on the first stator portion [integrally connected]. Crawley teaches the assembly is simple in construction and economical [col. 2, lines 16-18]. Marshall et al teach (16) wherein the first centrifugal pump 80 comprises a first rotor portion 80 and a first stator portion [either 30 or left of leadline for 82], and the second centrifugal pump 68 comprises a second rotor portion 68 and a second stator portion [either right of 72 or 30], the first rotor portion being integral in rotation 32 with the second rotor portion, and the second stator portion being mounted fixedly on the first stator portion [fixed via bolts 36]. [which are held together by bolts 36]. Marshall et al teach the assembly is without reciprocating parts and simple in construction [col. 1, lines 2023]. It would have been obvious to one of ordinary skill in the art to make the first centrifugal pump comprise a first rotor portion and a first stator portion, and the second centrifugal pump comprise a second rotor portion and a second stator portion, the first rotor portion being integral in rotation with the second rotor portion, and the second stator portion being mounted fixedly on the first stator portion, in the manner taught by either Crawley or Marshall et al, in order to employ an assembly that is simple in construction and/or economical. Both also Crawley and Marshall further teach (18) a rotating element [shaft] connected to at least one of the first rotor portion and the second rotor portion in order to drive the first rotor portion and the second rotor portion in rotation relative to the first stator portion and the second stator portion.
Claim(s) 18 is/are rejected under 35 U.S.C. 103 as being unpatentable over any of the above prior art in view of either Crawley (3,784,329) or Marshall et al (2,785,634), as applied above to claim 16, and further in view of Futa Jr et al (2010/0263634) and/or Mahoney et al (2009/0199823). The prior art do not necessarily teach an electric motor comprising a rotating element connected to at least one of the first rotor portion and the second rotor portion in order to drive the first rotor portion and the second rotor portion in rotation. Futa teaches (18) an electric motor [both 104, 106 may be driven by a electric motor, see end of paragraph 0017] comprising a rotating element connected to at least one of the first rotor portion and the second rotor portion in order to drive the first rotor portion and the second rotor portion in rotation relative to the first stator portion and the second stator portion. Alternately, Mahoney et al teach an electric motor 118 comprising a rotating element [e.g. shaft] connected to at least one of the first rotor portion 104 and the second rotor portion 106 in order to drive the first rotor portion and the second rotor portion in rotation relative to the first stator portion [stationary portion of 103] and the second stator portion [stationary portion of 106]. Mahoney et al teach the electric motor provides the drive torque to the first and second fuel pumps [see ¶ 0018] is typically done in the art in fuel control systems for gas turbine engines. It would have been obvious to one of ordinary skill in the art to employ an electric motor comprising a rotating element connected to at least one of the first rotor portion and the second rotor portion, as taught by Futa or Mahoney et al, in order to drive the first rotor portion and the second rotor portion in rotation relative to the first stator portion and the second stator portion, as a typical drive utilized in the art for the fuel pumps of gas turbine engines.
Response to Arguments
Applicant's arguments filed 3/20/2026 have been fully considered but they are not persuasive.
Applicant’s arguments concerning the 103 rejections, specifically the Chalaud combination and the Futa Jr et al combination are not persuasive. Applicant argues that
“Chalaud does not teach the Examiner's interpretation of elements "111a" and "111b".
Instead, Chalaud discloses that elements "111a" and "111b" are distinct centrifugal pumps, not various pressuring stages of the same centrifugal pump, as alleged by the Examiner.”
In rebuttal, Chalaud clearly teaches the element 110 is the second / downstream pumping unit 110 -- thus it has the pumping stages 111a and 111b as part of the same pumping unit. While “Chalaud” may use the term “pump” for each of 111a and 111b, Applicant’s arguments basically rely on semantics since a pumping unit may be considered a pump with different stages vs different pumps. There is nothing in the claims to distinguish a pumping unit with different pumps being considered the different pumping stages of the same pump, as Chalaud even groups them together as part of the same pumping unit.
For Davis, applicant argues
“Further, with respect to claim 11, the Examiner alleges Davis discloses the first centrifugal pump 12 introducing a first increase in a pressure of fuel circulating in the main circuit 34 which is less than a second increase in the pressure of fuel circulating in the main circuit 34 that is introduced by the second centrifugal pump 16, due to the second pump being allegedly much larger than the first pump.
Davis indicates that its figure is a schematic representation (see col. 2, lines 42 and 43), such that the skilled person would not derive any meaningful information from the figure regarding the relative dimensions of pumps 12 and 16.
Further, Applicant submits that any difference in pressure increase that would allegedly be disclosed by Davis would, in any case, be between the centrifugal boost pump 12 and the pump 16 of the main circuit 34, and not, as required by independent claim 11 of the present application, a difference in pressure increase between the pumps of the main circuit.”
Applicant’s arguments are not persuasive. MPEP 2125 states:
I. DRAWINGS CAN BE USED AS PRIOR ART
Drawings and pictures can anticipate claims if they clearly show the structure which is claimed. In re Mraz, 455 F.2d 1069, 173 USPQ 25 (CCPA 1972). However, the picture must show all the claimed structural features and how they are put together. Jockmus v. Leviton, 28 F.2d 812 (2d Cir. 1928). The origin of the drawing is immaterial. For instance, drawings in a design patent can anticipate or make obvious the claimed invention as can drawings in utility patents. When the reference is a utility patent, it does not matter that the feature shown is unintended or unexplained in the specification. The drawings must be evaluated for what they reasonably disclose and suggest to one of ordinary skill in the art. In re Aslanian, 590 F.2d 911, 200 USPQ 500 (CCPA 1979). See MPEP § 2121.04 for more information on prior art drawings as “enabled disclosures.”
As Fig. 1 of Davis [annotated below] clearly illustrates the second pump as being larger than the first, then one of ordinary skill in the art would accept that on face value. The illustration clearly teaches the second pump is larger in radius or that being larger in radius is encompassed by Chalaud.
Moreover, Applicant’s argument in the quoted last paragraph above concerning the difference in pressure is not well understood and is not persuasive, since Davis clearly teaches the pumps 12, 16 are of the main circuit and in combination with Chalaud would teach that the second pump would be higher in pressure increase / boost than the first pump.
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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.
Contact Information
Any inquiry concerning this communication or earlier communications from the Examiner should be directed to TED KIM whose telephone number is 571-272-4829. The Examiner can be reached on regular business hours before 5:00 pm, Monday to Thursday and every other Friday.
The fax number for the organization where this application is assigned is 571-273-8300.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Devon Kramer, can be reached at 571-272-7118 Alternate inquiries to Technology Center 3700 can be made via 571-272-3700.
Information regarding the status of an application may be obtained from Patent Center https://www.uspto.gov/patents/apply/patent-center. Should you have questions on Patent Center, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). General inquiries can also be directed to the Inventors Assistance Center whose telephone number is 800-786-9199. Furthermore, a variety of online resources are available at https://www.uspto.gov/patent
/Ted Kim/
Telephone
571-272-4829
Primary Examiner
Fax
571-273-8300
April 23, 2026
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