Measuring and testing – Volume or rate of flow – Using differential pressure
Patent
1994-05-17
1995-08-08
Williams, Hezron E.
Measuring and testing
Volume or rate of flow
Using differential pressure
73718, 73724, G01L 912
Patent
active
054388805
ABSTRACT:
An improved airspeed transducer for rotorcraft is disclosed having a pitot tube connected with a differential capacitive pressure sensor. The pressure differential from the pitot tube is a function of the airspeed squared. A diaphragm in the capacitive pressure sensor deflects when the dynamic pressure exceeds the static pressure from the pitot tube. This diaphragm deflection is sensed by electronics which provides an electrostatic attractive force between the diaphragm and a fixed plate such that the diaphragm is brought back to an undeflected, "at rest" position. The electrostatic force between the diaphragm and fixed plate is a function of the square of the voltage applied to the plate that creates this electrostatic force. Since the pressure differential from the pitot tube varies with the airspeed squared, the relationship between airspeed and feedback voltage is linear. Thus, the feedback voltage is a direct indication of sensed airspeed.
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Kosakowski Richard H.
Moller Richard A.
United Technologies Corporation
Williams Hezron E.
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