Pressurisation of enclosed chambers utilising fluid logic devices

摘要

1,138,868. Fluid-pressure servomotor systems. WESTLAND AIRCRAFT Ltd. Dec.15, 1966 [Jan. 18,1966], No. 2386/66. Heading G3P. A fluid operated pressurization control system for an aircraft cabin 11 includes a fluid logic element for sensing the rate of change of pressure within the cabin and valve means 63 for controlling the rate of change, the valve means being preset to limit the rate of change by opposing the rate signal developed by the fluid logic elements in an associated fluid element with a regulated bias pressure which has to be overcome before the rate signal, amplified as required, becomes operative through the remainder of the system, and actuating means to control the inflow and outflow of fluid from the chamber to maintain a predetermined pressure. When cabin pressure increases, a capsule 110 is compressed to open a valve 107 to lower the pressure in lines 102 and 105 which are connected through restrictions 103, 104 to a supply manifold 5. The fall in pressure deflects a jet from nozzle 96 to an outlet 115 of a fluid amplifier 97 and causes deflection of a jet 127 in a further amplifier 126 into a line 132 to inflate a bellows 134 and to open an outlet valve 142 from the cabin against the pressure of a spring 139. A fall in cabin pressure closes the valve 107 and deflects the jet from the amplifier 126 into an outlet 130. This amplifier is also controlled by a diaphragm actuated valve 119 responding to the difference between cabin and external pressure. To limit the rate of change of pressure, an amplifier 10 connected to a capacitor C and filter 12 acts through amplifiers 23, 33 and 43 on a pair of amplifiers 59, 54 oppositely biased by the supply from the valve 67. When the bias is overcome, the amplifier 59 or 54 causes jet deflection in an amplifier 79 and in the amplifer 97 in opposition to that caused by the capsule 110. The valve 67 determines the range of acceptable rates of cabin pressure variation. A feedback from the output line 132 is fed to control jets 82, 83 of the amplifier 79 and a capacitor 87 is provided to delay the pressure change in one direction. Reference has been directed by the Comptroller to Specification 1, 085, 925.