GB798709A - Improvements in or relating to pressure regulating devices - Google Patents

Abstract

798,709. Fluid-pressure servomotor-control systems; valves. STRUVER GES AGGREGATEBAU, A. April 20, 1956 [April 23, 1955], No. 12169/56. Class 135. In a fuelling arrangement in which a single pump supplies a plurality of independent systems, a valve shut-off device is provided at the end of each delivery pipe and a control shut-off device operated in accordance with the pressure in the constriction of a venturi tube is located before the delivery pipe. A pump (not shown) supplies two independent systems through a pipe 1, Fig. 1, which divides into two branches 2, 3 leading to two systems. Each branch contains a control shut-off device, e.g. a valve 4 and a venturi 7. The valve 4 has a housing 11 containing two closure members 12, 13. The member 12 controls the flow from the inlet 15 to the outlet 16 and the member 13 the flow from the inlet 15 to the by-pass 20. Fluid under pressure is taken from a tapping 45 in the branch 3 via pipes 46, 47 to the orifice of a pilot valve 6 the closure member 49 of which is connected to a piston 57 loaded by a fixed spring 62 and an adjustable spring 65. The working side 58 of the piston 57 is connected to the constriction of the venturi 7 by a pipe 61 and a bore 59. The chamber 53 of the valve 6 is connected via an orifice 52 and a pipe 20 to the cylinder chamber 19 above the member 12. The chamber 53 is also connected by an orifice 55 and a pipe 56 to the pump inlet. The rear side of the piston 57 is also connected to the pipe 56. The pressure drop at the constriction 10 of the venturi 7 is equal to the pressure drop due to flow in the associated flexible delivery pipe 9 and the arrangement is such that the closure member 49 of the pilot valve 6 assumes a position according to the pressure at the venturi constriction so as to determine the pressure in the cylinder chamber 19 and so position the closure members 12 and 13 accordingly. The closure member 13 has a cylindrical extension 25 which seats in a casing 23. The extension 25 and casing 23 having superposed apertures 26, 24 respectively so that by rotation of the closure member 13 the by-pass can be adjusted. The position of the member 13 can be viewed through glass-covered openings 43, 44 in the housing 11. The adjustment of the loading spring 65 of the pilot valve may be viewed through a window 73. The pressure at the constriction of the venturi tube 7 can be used to act directly on the closure members 12, 13 which in this case may be loaded by compressed gas, preferably compressed air.