Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
185 words
A fuel control system for a gas turbine engine having a compressor, comprising a fuel pump, a venturi connected between the fuel pump and the engine, fuel flowing from the pump to the engine passing through said venturi, a fuel pressure control device sensitive to the fuel pressures upstream of said venturi and at the throat of said venturi for varying the fuel pressure upstream of the venturi, loading means providing a bias for said fuel pressure control device against which the difference between said fuel pressures is balanced, said loading device being responsive to an air pressure signal applied thereto from the engine compressor, a governor mechanism driven by the engine at a speed proportional to the engine speed for modifying the air pressure signal applied to said loading device in accordance with the relationship between the desired and actual running speeds of the engine and causing the engine speed to approach the desired speed and a temperature sensitive resilient device acting on said loading means to further modify the bias applied thereby to the fuel pressure control device in accordance with ambient temperature.
Claim 2
Dependent Claim
185 words
A fuel control system for a gas turbine engine having a compressor, comprising a fuel pump, a venturi connected between the fuel pump and the engine, fuel flowing from the pump to the engine passing through said venturi, a fuel pressure control device sensitive to the fuel pressures upstream of said venturi and at the throat of said venturi for varying the fuel pressure upstream of the venturi, loading means providing a bias for said fuel pressure control device against which the difference between said fuel pressures is balanced, said loading device being responsive to an air pressure signal applied thereto from the engine compressor, a governor mechanism driven by the engine at a speed proportional to the engine speed for modifying the air pressure signal applied to said loading device in accordance with the relationship between the desired and actual running speeds of the engine and causing the engine speed to approach the desired speed and a temperature sensitive resilient device acting on said loading means to further modify the bias applied thereby to the fuel pressure control device in accordance with ambient temperature.
Claim 3
Dependent Claim
22 words
A system as claimed in claim 1 in which the fuel pressure control device comprises a spill valve upstream of the venturi.
Claim 4
Dependent Claim
51 words
A system as claimed in claim 2 in which the spill valve is actuated in a direction to increase spillage by the said pressure upstream of the venturi and in a direction to decrease spillage by the said loading means and by the said pressure at the throat of the venturi.
Claim 5
Dependent Claim
17 words
A system as claimed in claim 1 in which the temperature sensitive device comprises a bimetallic spring.
Claim 6
Dependent Claim
34 words
A system as claimed in claim 1 in which the loading means includes a pair of diaphragms which define between them a volume to which, in use, the said air pressure signal is applied.
Claim 7
Dependent Claim
23 words
A system as claimed in claim 5 in which one of the said diaphragms has an area greater than that of the other.
Claim 8
Dependent Claim
90 words
A system as claimed in claim 6 in which said one diaphragm is coupled to the fuel pressure control device and said other diaphragm is urged towards said one diaphragm by biasing means and a further comprising a pair of abutments carried respectively by said diaphragms and interengaged when the air pressure signal has a value less than a predetermined value, whereby the spring force is applied through said abutments to the fuel pressure device, said abutments separating when the air pressure signal has a value above said predetermined value.
Claim 9
Dependent Claim
34 words
A system as claimed in claim 1 in which said governor comprises a kinetic nozzle controlled by a movable blade movable by means responsive to the relationship between the desired and actual engine speeds.
Claim 10
Dependent Claim
40 words
A system as claimed in claim 8 in which the said responsive means comprises a lever coacting both with a speed responsive mechanism driven at a speed proportional to the engine and with a linkage to the engine throttle control.