| 摘要 |
772,588. Measuring pressure. KOLLSMAN INSTRUMENT CORPORATION. Nov. 22, 1955 [June 15, 1955], No. 33408/55. Class 40 (1). [Also in Group XXXV] The pressure in a line 11 leading to the instruments operated by static pressure on an aircraft is automatically maintained at a value differing from that in the normal static pressure line 10 communicating with the outside of the craft by an amount which compensates for errors under varying flight conditions. As shown, the difference in pressure between the lines 10, 11 is measured by a barometric capsule which controls the position of a metallic armature 51 in relation to an inductive bridge supplied with 400-cycle current. The output of the bridge, which feeds a potential divider 57, thus represents the actual pressure difference. A computer device 30 gives a 400-cycle output which is a temperature-corrected function of the readings of instruments A, B, C, &c., measuring for example Mach number, altitude, airspeed, angle of attack, &c., and which represents the desired pressure difference. The difference between the two 400-cycle outputs (subject to the effect of the position of the slider of the potential divider) drives a reversible motor 21 coupled to a positive-displacement pump acting differentially with the aid of conduits 16, 17 separated by an apertured plate on the pressure lines 10, 11. When the pressure-difference is correct the motor stops. In a modification, Fig. 2 (not shown), the signals from the pressure gauge and the computer are applied to the amplifier valve in parallel instead of in series. If the motor fails, the line 11 acquires the pressure in the line 10. |
