GB898777A - Fluid-flow metering valves - Google Patents

Abstract

898,777. Valves. FIFE, I .L. Aug. 11, 1958, No. 25762/58. Class 135. A diaphragm-operated plunger valve comprises a housing 12 having a plunger 44 disposed within a bore 50 and actuated by a diaphragm 22. The plunger 44 is provided with three grooves 92, 94 and 96, the groove 94 having ports 95 communicating with an internal bore 100. The plunger 44 slides within a liner 52 secured in the valve housing 12, the liner 52 having three external grooves 82, 84 and 86. The grooves 82 and 86, Fig. 6, are provided with a plurality of relatively small spaced ports 88 and 90 respectively. A plurality of circumferentially spaced ports 89 are provided in groove 82 below the ports 88. Similarly, a plurality of circumferentially spaced ports 91 are provided in groove 86 above the ports 90. The central groove 84 has a single port 85. The valve housing has three ports 76, 78 and 80 and the liner 52 is secured in the housing such that the group of ports 90 are adjacent the port 80 and the group of ports 88 adjacent the port 76, the port 85 being aligned with the port 78. The diaphragm 22 is subject on its upper surface to loading from an adjustable spring 34. The lower surface of the diaphragm is open to atmospheric pressure through the bore 50, chamber 74, passage 72, chamber 70 and bore 62. To actuate the valve a vacuum is introduced into the compartment 24 above diaphragm 22, causing the diaphragm to be deflected upwards. In the position of the plunger shown in Fig. 3, pressure fluid entering at port 78 passes, via groove 92 of the plunger 44, to the group of ports 90 in the sleeve 52 and from there out through port 80 to actuate a fluid motor. Exhaust fluid returning from the fluid motor enters port 76 and passes through the circumferential ports 89 to the bore 50 below the plunger 44 and thence to exhaust through the pipe 64. When the plunger 44 in the lowermost position port 80 then becomes the exhaust port and port 76 the supply port to the fluid motor. The ports in the liner grooves 82 and 86 are so disposed that whatever position is assumed by the plunger 44, other than the neutral position, the total area open to exhaust from the fluid motor is always greater than the total area through which fluid passes to the fluid motor from the valve in order to eliminate hydraulic knocking. The degree of vacuum in the chamber 24 may be determined by a sensing head or feeler member.