Patent US4117668A successfully refreshed from Google Patents.
US4117668A
Expired / Lapsed
US
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Stall detector for gas turbine engine
Assignee: RTX Corp
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Filing: 1975-11-19
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Granted: 1978-10-03
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Expires: 1995-11-19
Abstract
Abstract Stall is detected by monitoring the acceleration schedule of the engine's fuel control and an engine operating parameter, either compressor speed, compressor pressure and computing signals indicative of when both the fuel control is on or near the acceleration schedule and when (1) the compressor speed is decaying at a given rate or (2) compressor discharge or burner pressure is decaying at a given rate or (3) the pressure ratio of low compressor discharge to compressor inlet or burner pressure to compressor inlet is at a predetermined low level, an output signal will be manifested.
Inventors
- 👤 Fred L. Elsaesser
- 👤 Joseph H. Hall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:12
CPC Classifications
F; F02; F02C; F02C7/00
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
129 words
Stall detector for a gas turbine engine having a compressor, burner and turbine, in combination with a fuel control having a fuel metering valve regulating the flow of fuel to the burner and independent coordinating means providing an acceleration schedule limiting said fuel metering valve, said stall detector including means responsive to said acceleration schedule for producing a first signal whenever said fuel control is on or near the acceleration schedule, means responsive to the rate of change of speed of said compressor for producing a second signal when the rate of speed decay exceeds a predetermined value and means responsive to both said first signal and said second signal for producing a third signal indicative of stall solely when said first signal and said second signal are received.
Claim 2
Dependent Claim
129 words
Stall detector for a gas turbine engine having a compressor, burner and turbine, in combination with a fuel control having a fuel metering valve regulating the flow of fuel to the burner and independent coordinating means providing an acceleration schedule limiting said fuel metering valve, said stall detector including means responsive to said acceleration schedule for producing a first signal whenever said fuel control is on or near the acceleration schedule, means responsive to the rate of change of speed of said compressor for producing a second signal when the rate of speed decay exceeds a predetermined value and means responsive to both said first signal and said second signal for producing a third signal indicative of stall solely when said first signal and said second signal are received.
Claim 3
Dependent Claim
25 words
A stall detector as in claim 1 wherein the engine is of the twin spool design and the speed sensed is the low compressor speed.
Claim 4
Dependent Claim
17 words
A stall detector as claimed in claim 2 wherein the speed sensed is the high compressor speed.
Claim 5
Dependent Claim
42 words
A stall detector as claimed in claim 1 including means for holding for a predetermined time said second signal so as to admit said second signal to said means responsive to said first and second signals solely when a predetermined time lapses.
Claim 6
Dependent Claim
40 words
A stall detector as claimed in claim 1 including means for holding the output signal produced by said means responsive to said first signal and said second signal a predetermined time prior to its being utilized for a stall signal.
Claim 7
Dependent Claim
86 words
A stall detector as claimed in claim 1 including means for holding for a predetermined time said second signal prior to its input into said means responsive to said first signal and said second signal and means for holding the output of said means responsive to said first signal and said second signal a predetermined time so that the input and output of said means responsive to said first signal and second signal will be held a predetermined time before a stall signal will be manifested.
Claim 8
Dependent Claim
66 words
A stall detector as claimed in claim 1 wherein said fuel control includes means responsive to speed of said compressor and compressor inlet temperature for producing a scheduled signal indicative of desired acceleration of the engine, comparator means for comparing said scheduled signal with a reference signal to provide an output signal representative of when said fuel control is operating on or near the acceleration schedule.
Claim 9
Dependent Claim
56 words
A stall detector as claimed in claim 7 wherein said acceleration schedule signal is indicative of ratio unit of the fuel flow in pounds per hour and compressor discharge pressure in pounds per square inch absolute and means responsive to actual compressor discharge pressure for multiplying the acceleration schedule signal for regulating said fuel metering valve.
Claim 10
Dependent Claim
132 words
Stall detector for an axial flow gas turbine engine having a compressor, burner and turbine, in combination with a fuel control having a fuel metering valve regulating the flow of fuel to the burner and independent coordinating means providing an acceleration schedule limiting said fuel metering valve, said stall detector including means responsive to said acceleration schedule for producing a first signal whenever said fuel control is on or near the acceleration schedule, means responsive to the rate of change of pressure of said compressor for producing a second signal when the rate of pressure decay exceeds a predetermined value and gate means responsive to both said first signal and said second signal for producing an output signal indicative of stall solely when said first signal and said second signal are received.
Claim 11
Dependent Claim
132 words
Stall detector for an axial flow gas turbine engine having a compressor, burner and turbine, in combination with a fuel control having a fuel metering valve regulating the flow of fuel to the burner and independent coordinating means providing an acceleration schedule limiting said fuel metering valve, said stall detector including means responsive to said acceleration schedule for producing a first signal whenever said fuel control is on or near the acceleration schedule, means responsive to the rate of change of pressure of said compressor for producing a second signal when the rate of pressure decay exceeds a predetermined value and gate means responsive to both said first signal and said second signal for producing an output signal indicative of stall solely when said first signal and said second signal are received.
Claim 12
Dependent Claim
34 words
A stall detector according to claim 9 wherein said axial flow engine is a twin spool type, and wherein said pressure is indicative of the pressure at the discharge end of the high compressor.
Claim 13
Dependent Claim
32 words
A stall detector according to claim 9 wherein said axial flow engine is a twin spool type and wherein said pressure is indicative of the pressure intermediate the high and low compressors.
Claim 14
Dependent Claim
36 words
A stall detector as claimed in claim 9 including means for holding for a predetermined time said second signal so as to admit said second signal to said gate means solely when a predetermined time lapses.
Claim 15
Dependent Claim
32 words
A stall detector as claimed in claim 9 including means for holding the output signal produced by said gate means a predetermined time prior to its being utilized for a stall signal.
Claim 16
Dependent Claim
63 words
A stall detector as claimed in claim 9 including means for holding for a predetermined time said second signal prior to its input into said gate means and means for holding the output of said gate means a predetermined time so that the input and output of said gate means will be held a predetermined time before a stall signal will be manifested.
Claim 17
Dependent Claim
66 words
A stall detector as claimed in claim 9 wherein said fuel control includes means responsive to speed of said compressor and compressor inlet temperature for producing a scheduled signal indicative of desired acceleration of the engine, comparator means for comparing said scheduled signal with a reference signal to provide an output signal representative of when said fuel control is operating on or near the acceleration schedule.
Claim 18
Dependent Claim
56 words
A stall detector as claimed in claim 15 wherein said acceleration schedule signal is indicative of ratio units of the fuel flow in pounds per hour to compressor discharge pressure in pounds per square inch absolute and means responsive to actual compressor discharge pressure for multiplying the acceleration schedule signal for regulating said fuel metering valve.
Claim 19
Dependent Claim
163 words
Stall detector for an axial flow gas turbine engine having a compressor, burner and turbine, in combination with a fuel control having a fuel metering valve regulating the flow of fuel to the burner and independent coordinating means providing an acceleration schedule limiting said fuel metering valve, said stall detector including means responsive to said acceleration schedule for producing a first signal whenever said fuel control is on or near the acceleration schedule, means responsive to inlet pressure of said compressor for producing a second signal, means responsive to compressor discharge pressure for producing a third signal and means responsive to both said second signal and said third signal for producing a fourth signal indicative of the ratio of said second and third signal, and gate means responsive to both the first signal when it is on or near the acceleration schedule and said fourth signal when it is below a predetermined value for producing an output signal indicative of a stall condition.
Claim 20
Dependent Claim
163 words
Stall detector for an axial flow gas turbine engine having a compressor, burner and turbine, in combination with a fuel control having a fuel metering valve regulating the flow of fuel to the burner and independent coordinating means providing an acceleration schedule limiting said fuel metering valve, said stall detector including means responsive to said acceleration schedule for producing a first signal whenever said fuel control is on or near the acceleration schedule, means responsive to inlet pressure of said compressor for producing a second signal, means responsive to compressor discharge pressure for producing a third signal and means responsive to both said second signal and said third signal for producing a fourth signal indicative of the ratio of said second and third signal, and gate means responsive to both the first signal when it is on or near the acceleration schedule and said fourth signal when it is below a predetermined value for producing an output signal indicative of a stall condition.
Claim 21
Dependent Claim
32 words
A stall detector as in claim 17 wherein the engine is of the twin spool design and wherein said third signal is the pressure at the discharge end of the low compressor.
Claim 22
Dependent Claim
66 words
A stall detector as claimed in claim 17 wherein said fuel control includes means responsive to speed of said compressor and compressor inlet temperature for producing a scheduled signal indicative of desired acceleration of the engine, comparator means for comparing said scheduled signal with a reference signal to provide an output signal representative of when said fuel control is operating on or near the acceleration schedule.
Claim 23
Dependent Claim
56 words
A stall detector as claimed in claim 17 wherein said acceleration schedule signal is indicative of ratio units of the fuel flow in pounds per hour and compressor discharge pressure in pounds per square inch absolute and means responsive to actual compressor discharge pressure for multiplying the acceleration schedule signal for regulating said fuel metering valve.
Claim 24
Dependent Claim
50 words
Stall detector in accordance with claim 17 including means for unlatching the output of said gate means to decouple the stall detector whenever the engine is stopped and the engine is restarted during a flight condition of the aircraft, and said means being controlled by the operator of the aircraft.
Claim 25
Independent Claim
126 words
The method of detecting stall in an axial flow gas turbine engine that includes a compressor, turbine and burner and a fuel control that schedules the engine operation by including its acceleration, comprising the steps of: measuring the schedule of the fuel control so as to produce an output signal whenever the fuel control is operating on the acceleration schedule, measuring another parameter of engine operation of the compressor so as to produce an output signal whenever the other parameter is abnormal with respect to normal engine operation, combining the outputs obtained in the steps of measuring so as to produce a signal indicative of stall solely when both signals are present which signal can then be used as a warning or to initiate correction action.
Claim 26
Independent Claim
126 words
The method of detecting stall in an axial flow gas turbine engine that includes a compressor, turbine and burner and a fuel control that schedules the engine operation by including its acceleration, comprising the steps of: measuring the schedule of the fuel control so as to produce an output signal whenever the fuel control is operating on the acceleration schedule, measuring another parameter of engine operation of the compressor so as to produce an output signal whenever the other parameter is abnormal with respect to normal engine operation, combining the outputs obtained in the steps of measuring so as to produce a signal indicative of stall solely when both signals are present which signal can then be used as a warning or to initiate correction action.
Claim 27
Independent Claim
125 words
The method of detecting stall in an axial flow gas turbine engine that includes a compressor, turbine and burner and a fuel control that schedules the engine operation including scheduling its acceleration, comprising the steps of: measuring the schedule of the fuel control so as to produce an output signal whenever the fuel control is operating on the acceleration schedule, measuring the rotational speed of the compressor so as to produce an output signal whenever the rate of decay of that speed exceeds a predetermined value, combining the outputs obtained in the steps of measuring so as to produce a signal indicative of stall solely when both signals are in existence, which signal can then be used as a warning or to initiate corrective action.
Claim 28
Independent Claim
125 words
The method of detecting stall in an axial flow gas turbine engine that includes a compressor, turbine and burner and a fuel control that schedules the engine operation including scheduling its acceleration, comprising the steps of: measuring the schedule of the fuel control so as to produce an output signal whenever the fuel control is operating on the acceleration schedule, measuring the rotational speed of the compressor so as to produce an output signal whenever the rate of decay of that speed exceeds a predetermined value, combining the outputs obtained in the steps of measuring so as to produce a signal indicative of stall solely when both signals are in existence, which signal can then be used as a warning or to initiate corrective action.
Claim 29
Dependent Claim
25 words
The method of claim 23 where the engine is a twin spool design and wherein the step of measuring includes sensing the low compressor speed.
Claim 30
Dependent Claim
25 words
The method of claim 23 where the engine is a twin spool design and wherein the step of measuring includes sensing the high compressor speed.
Claim 31
Independent Claim
130 words
The method of detecting stall in an axial flow gas turbine engine that includes a compressor, turbine and burner and a fuel control that schedules the engine operation by including its acceleration, comprising the steps of: measuring the schedule of the fuel control so as to produce an output signal whenever the fuel control is operating on the acceleration schedule, measuring the pressure of the air at or in proximity to the compressor so as to produce an output signal whenever the rate of decay of that pressure exceeds a predetermined value, combining the outputs obtained in the steps of measuring so as to produce a signal indicative of stall solely when both signals are present which signal can then be used as a warning or to initiate corrective action.
Claim 32
Independent Claim
130 words
The method of detecting stall in an axial flow gas turbine engine that includes a compressor, turbine and burner and a fuel control that schedules the engine operation by including its acceleration, comprising the steps of: measuring the schedule of the fuel control so as to produce an output signal whenever the fuel control is operating on the acceleration schedule, measuring the pressure of the air at or in proximity to the compressor so as to produce an output signal whenever the rate of decay of that pressure exceeds a predetermined value, combining the outputs obtained in the steps of measuring so as to produce a signal indicative of stall solely when both signals are present which signal can then be used as a warning or to initiate corrective action.
Claim 33
Dependent Claim
31 words
The method of claim 26 wherein the engine is a twin spool design and the pressure measured in the step of measuring is the pressure intermediate the low and high compressors.
Claim 34
Independent Claim
148 words
The method of detecting stall in an axial flow gas turbine engine that includes a compressor, turbine and burner and a fuel control that schedules the engine operation by including its acceleration, comprising the steps of: measuring the schedule of the fuel control so as to produce an output signal whenever the fuel control is operating on the acceleration schedule, measuring the pressure of the air at the inlet and its outlet of the compressor, dividing the values of the inlet and outlet pressures obtained in the step of measuring to obtain an output indicative of the ratio of these two pressures, combining the outputs obtained in the steps of measuring the schedule of the fuel control and dividing so as to produce a signal indicative of stall soley when both outputs are present which signal can then be used as a warning or to initiate corrective action.
Claim 35
Independent Claim
148 words
The method of detecting stall in an axial flow gas turbine engine that includes a compressor, turbine and burner and a fuel control that schedules the engine operation by including its acceleration, comprising the steps of: measuring the schedule of the fuel control so as to produce an output signal whenever the fuel control is operating on the acceleration schedule, measuring the pressure of the air at the inlet and its outlet of the compressor, dividing the values of the inlet and outlet pressures obtained in the step of measuring to obtain an output indicative of the ratio of these two pressures, combining the outputs obtained in the steps of measuring the schedule of the fuel control and dividing so as to produce a signal indicative of stall soley when both outputs are present which signal can then be used as a warning or to initiate corrective action.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-10-02 | 1982-04-03 | 1982-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-10-02 | 1986-04-03 | 1986-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-10-02 | 1990-04-03 | 1990-10-03 | $7700.00 | Window Closed / Lapsed |