Rate of Change of Pressure Control

摘要

1,167,316. Fluid-pressure servomotor systems. WESTLAND AIRCRAFT Ltd. Aug.25, 1967 [Aug.30, 1966], No.38711/66. Heading G3P. A system for obtaining an output related to rate of change of pressure from a fluid amplifier 7 vented to ambient includes a fluid power jet 6 directed to vent to one or more output channels 17, 18 by interaction with at least one pair of control nozzles 10, 13 opposed to each other in their effect upon the power jet fluid-flowing from a source 3 of fluid above ambient pressure through ducts 12, 15 to the pair of control nozzles and one of the ducts having a greater volumetric capacity than the other in order to cause a lead or lag of fluid-pressure between the control nozzles during a pressure change. A capacity 16, which may be variable, causes a delay in the pressure change at nozzle 13 so that an ambient pressure change causes a signal to appear in one of the two output channels 17, 18, the signal being communicated either through amplifiers 19, 39 or 20, 40 to a final amplifier 56 controlling an indicator or an actuator 62 for a pressurization control system. The amplifiers 19, 20 are supplied with fixed bias pressures through nozzles 25, 26 separately connected through restrictions 27, 28 to the source 3 while the amplifiers 39, 40 receive a variable bias pressure through an adjustable restriction 49 and a fixed restriction 41 which also supplies the power nozzles of the latter pair of amplifiers. The bias pressures may be altered to adjust the range of pressure variations to which the system will respond. The source 3 is provided with a relief valve 5 and a reducing valve 4 through which it may receive its supply from the engine 2 of an aircraft when the system is used for cabin pressurization. Liquid or gaseous media may be used and the restrictions may be orifices, capillaries or needle valves. Reference has been directed by the Comptroller to Specification 1,138,868.