Thomas James Randolph

US Patent:

39355586, Jan 27, 1976

Filed:

Dec 11, 1974

Appl. No.:

5/531636

Inventors:

Ronald J. Miller - North Palm Beach FL
Thomas M. Randolph - Palm Springs FL

Assignee:

United Technologies Corporation - Hartford CT

International Classification:

G01M 1500
F02C 902

US Classification:

340 27SS

Abstract:

A pair of pressure transducers are connected to pressure probes positioned in a flow passage of a turbofan engine downstream of the fan and respond to pressure fluctuations which occur in the airstream. One transducer has a high response capability, and its output is passed through a band-pass filter to isolate the high frequencies of interest. The other transducer has a low response capability, and its output is passed through a low-pass filter to provide the steady state pressure level. A triggering level is scheduled as a function of the steady state pressure level, and a comparator is used to continuously compare the triggering level with the level of the high frequency pressure signal produced in the band-pass filter. If the amplitude of the high frequency pressure is greater than that of the triggering level, the engine is approaching a surge or stall condition, and a warning signal is generated which may be used to institute corrective action.