GB678267A - Flow control valve - Google Patents

Abstract

678,267. Fluid-pressure servomotor-control systems. GARRETT CORPORATION. Feb. 13, 1948 [March 3, 1945], No. 4313/48. Class 135. A flow control valve has a valve member 30 actuated by a pressure responsive member such as the diaphragm 10 having a chamber D on one side in free communication with the high pressure side of the valve and a chamber C on its other side in restricted communication with the high pressure side of the valve and in communication with the outlet side of the valve through a pilot valve 19 actuated by a further pressure responsive member such as the diaphragm 8 movable in accordance with the velocity head of the incoming fluid. The figure shows an axial flow arrangement suitable for the air inflow control of an aircraft cabin. The diaphragm 8 separates a chamber B subject to the static inlet pressure through a port 12 from a chamber A subject to the combined static and dynamic pressure head through an opening 7 in a conical nose 6 forming part of a core member 4 spaced from the wall 32 to form an annular duct 5. The loose-fitting annular valve 30 in the outlet 3 and also the diaphragm 10 are clamped to a hollow stem 16 opening into the outlet 3. The stem 16 has a port 17 controlled by the valve 19 and opening into the chamber C. The combined static and velocity head in the duct 5 acts in the chamber D through a scoop tube 26 with an orifice 27 whilst the static head is communicated to the chamber C past an adjustable needle valve 57. The hollow stem 16 is guided in partitions 9, 11 and forms a guide for the valve 19 the stem of which has a head 20 maintained against the diaphragm 8 by a light spring 21. A further spring 56 acts on the diaphragm 10 in a direction to close the main valve 30.