Application of Alexander M. Wright

343 F.2d 761, 52 C.C.P.A. 1185
CourtCourt of Customs and Patent Appeals
DecidedApril 15, 1965
DocketPatent Appeal 7218
StatusPublished
Cited by4 cases

This text of 343 F.2d 761 (Application of Alexander M. Wright) is published on Counsel Stack Legal Research, covering Court of Customs and Patent Appeals primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Application of Alexander M. Wright, 343 F.2d 761, 52 C.C.P.A. 1185 (ccpa 1965).

Opinion

RICH, Judge.

This appeal is from the decision of the Patent Office Board of Appeals, adhered to on reconsideration, affirming the rejection of claims 15 through 28 of application serial No. 688,459, filed October 7, 1957, for “Afterburner Fuel Regulator Responsive to Compressor Discharge Absolute Pressure.” No claims are allowed.

The Invention

The invention relates to fuel control apparatus for aircraft turbojet engines having an “afterburner” combustion chamber, supplemental to and on the discharge side of, a “main” combustion chamber for reheating exhaust gases and thereby increasing the jet reaction thrust of the engine when maximum power output is desired, such as on take-off. As explained in the specification—

“Engines of this type usually comprise, as principal elements, an air inlet, an air compressor, one or more main combustion chambers having a series of burner nozzles through which the main fuel supply is fed, a gas turbine, a supplementary combustion chamber also having a series of burner nozzles through which the supplementary fuel supply is fed, and a tail pipe for discharging the combustion gases to the atmosphere in the form of a jet. Associated with the engine are a main fuel supply system, including a fuel pump and control apparatus, for delivering fuel to the main combustion chambers, and a supplementary fuel supply system, including a fuel pump and control apparatus, for delivering fuel to the *762 afterburners in the afterburner combustion chamber. This invention is particularly concerned with the afterburner fuel control apparatus which controls the afterburner fuel flow as a preselected function of the compressor discharge absolute pressure.”

The specification goes on to say the “invention consists in the combination and arrangement of elements hereinafter described and illustrated * * (Emphasis ours.)

Appellant’s Figure 1, reproduced below since one of the two issues presented by the appeal has a direct bearing thereon, diagrammatically shows a turbojet aircraft engine with its associated main fuel supply and afterburner fuel supply system, including appellant’s “control” apparatus, and the principal connections therebetween.

The main elements are: a supporting casing 10, an air inlet 12, a multistage air compressor 14 having a rotor shaft 16, one of a number of main combustions ■chambers 18, one of a corresponding number of main fuel burner nozzles 20, ■connected to a generally circular fuel manifold 22 by means of a conduit 24, a multistage turbine 26 having a rotor shaft 28 connected to compressor rotor .shaft 16; an afterburner combustion ■chamber 80, one of a plurality of afterburner fuel nozzles 32, a tail pipe 34 for ■discharging combustion exhaust; a center bearing 36 and end bearings 38 and 40 supported by casing 10, and a gear train 42 connected to shaft 16 for operating the fuel pumps and other accessories at a speed proportional to the engine speed.

The fuel supply system includes a supply tank 44 connected to a fuel pump unit 46 comprising a centrifugal pump 48, connected by a conduit 49 in series with a pair of parallel, positive displacement pumps 50 and 52, which supply fuel through conduits 56 and 54, respectively, to a main fuel control apparatus 58' and an afterburner fuel control apparatus 60. All three pumps 48, 50, *763 and 52 are connected to gear train 42 as shown by the broken lines, whereby they are driven at a speed proportional to engine speed. Fuel, controlled by a pilot’s manual control 62, is supplied by main fuel control 58 through conduits 64 and 24 to nozzles 20 in the main combustion chamber 18 for the operation of turbine 26; and fuel not required'by the turbine is returned from main fuel control 58, through a conduit 66, to conduit 49 on the inlet side of pump 50.

Similarly, fuel at a regulated rate is supplied by the afterburner fuel control 60, through conduits 68 and 69, to afterburner nozzles 32; and fuel not required for afterburning is returned from afterburner fuel control 60, through a conduit 70, to conduit 49 on the inlet side of pump 52.

Appellant’s brief says:

“As shown in Fig. 1 of the drawings * * * applicant’s invention, broadly comprehended, comprises an afterburner fuel control apparatus 60, for regulating the fuel flow to afterburners 32 in afterburner combustion chamber 30, which is used in operative association with a main fuel control apparatus 58 for regulating the fuel flow to main burner nozzles 20 in main combustion chamber 18. [Emphasis ours.]
“One of the basic requirements for fuel control apparatus for turbojet engines is that the total fuel flow to the engine should always bear a preselected, definite, scheduled ratio to the weight [mass?] air flow through the engine, under all operating conditions; and since the total fuel flow to the engine consists of the fuel flow to the main burners 20, and the fuel flow to the afterburners 32, the regulating of the main fuel flow by main control apparatus 58 must be fully coordinated with the regulation of the afterburner fuel flow by afterburner control apparatus 60, This coordination of fuel flows is obtained by the * * * arrangement of elements * * * shown in Fig. 1
* * *^
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“Since one of the cardinal features of applicant’s invention is regulation of the fuel flow to the main combustion chamber and the afterburner, in accordance with the rate of mass air flow through the engine, and since compressor discharge abso-^ lute pressure is a measure of said air flow, it is essential that said pressure be the sole control parameter that automatically regulates said fuel flow, because any modification of said pressure would causé said fuel flow to be-not in accordance with said air flow. Since applicant’s invention is particularly concerned with apparatus for regulating the fuel flow to the afterburner, the main fuel control apparatus is involved only to the extent that it cooperates in association with the afterburner control apparatus (as shown in Fig. 1), the details of construction of the main control apparatus form no part of applicant’s invention, beyond the arrangement whereby (as shown in Fig. 1), it automatically regulates the fuel flow in accordance with same control parameter as the afterburner fuel control (i. e. compressor discharge absolute pressure). Accordingly, the details of construction of the main fuel control apparatus will not be further described herein since they may be any combination and arrangement of elements that operate to regulate the fuel flow to the main combustion chamber in accordance with the compressor discharge absolute pressure, as for the example of a combination and arrangement of pertinent elements similar to those of the afterburner fuel control apparatus, as hereinafter described, and illustrated in the drawings * * *»>

The afterburner fuel' control apparatus 60, the drawing of which is full of complex detail and not reproduced here since *764

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343 F.2d 761, 52 C.C.P.A. 1185, Counsel Stack Legal Research, https://law.counselstack.com/opinion/application-of-alexander-m-wright-ccpa-1965.