Patent GB-820404-A (GB)
Title: Improvements in fluid flow control valves
IPC: F16K11/07
Filed: 1956-05-25
Abstract: 820,404. Valves controlled by auxiliary valves. JOHNSON, C. May 25, 1956 [June 17, 1955], No. 16282/56. Class 135. A slide valve assembly for controlling a fluid-pressure actuated device comprises a housing 11 with inlet, control, and exhaust ports 108, 142, 144, 140 and a slide valve member 20 with sealed piston parts 72, 76 of different size at its opposite ends, the valve member being movable in opposite directions under the control of a pilot valve unit 89 comprising a double-acting shut-off part 98 adapted to connect the chamber 72a at one side of the larger piston part 72 alternatively with an inlet chamber 14 or with an exhaust chamber 16 according to the state of the fluid pressure actuated device, the chamber 74 on the other side of the larger piston part being permanently vented to the exhaust chamber 16 to prevent a pressure lock therein by passages 133, 131, 134. As shown, the pilot valve unit is operated by a solenoid 180, the pilot valve unit and the solenoid 180 being enclosed in a common casing 190 having a base section 191 and a cover section 192, each section having a pair of opposed inclined mating sides 195. The short bottom wall 194 of the base section provided ready access to the solenoid and the parts operated thereby whilst the long top wall 193 is furnished with a fitting 196 for the solenoid leads. The section 191 has a lip 202 to accommodate an O-ring seal 200 and the two sections are secured by captive screws 197. Fig. 2 shows a four-way valve generally similar to that shown in Fig. 2 of Specification 731,332. The inlet port 108 leads to the inlet chamber or manifold 14. The exhaust port 140 is connected to the exhaust chamber 16. Liner elements 24, 26, 28, 30 spaced by cylindrical filter elements 32 are mounted in a valve bore 12. The exteriors of the liner elements and the lands 58, 60, 62 of the valve member 20 are provided with O-ring seals. Ports 120, 122 between the bore 12 and the exhaust chamber 16 are controlled by adjustable metering valves or screws 135. One end of the housing 11 is closed by a plate 80 with an apertured gasket 81 interposed to connect the chamber 14 permanently with an end chamber 70. The other end of the housing is closed by a base-plate 84 forming part of the base section 191, an aperture 102 in a gasket 86 connecting the chamber 14 to the pilot valve unit 89. The latter comprises a bore 88 with spaced inserts 90, 92 furnished with O-ring seals 94, 96 to provide alternate seats for a loose ball valve 98 which constitutes the shut-off part. A third insert or sleeve 91 in the bore 88 carries an O-ring seal 95 which supports a pin 99 adapted to displace the ball 98 from its seat 96 against the pressure in the inlet chamber 14. A chamber 72a to the right of the piston 72 is of larger diameter than the chamber 70 and is connected by a passage 106 to the space between the seat rings 94, 96. Passages 101, 103 connect the bore 88 to the right of the ring 96 to the exhaust chamber 16. The pin 99 has a reduced end 170 passing with clearance through a hole 169 in a lever 162. The lever has an arcuate section 163 pivoted about a fixed pin 165 integral with blocks 166 secured to the plate 84 by screws 172. The lever 162 is loaded to urge the ball 98 against the seat 94 by a spring 179 adjustable by a nut 175 on a fixed pin 176. In the event of failure of the solenoid, the lever 162 may be operated manually on removal of the cover section 192. The solenoid 180 comprises a plunger 182 connected to the lever 162 by a U-shaped stirrup 184. A pin passing through the plunger 182 and the stirrup has at each end a pair of O-rings of different size. The plate 80 may be replaced by a second pilot valve and solenoid unit as in the casing 190. The invention is also shown applied to a threeway valve. In this case the main valve 20 has only two lands, one of the ports 120, 122, its metering valve, and also one of the outlet ports 142, 144 are dispensed with. Figs. 9, 10 show the valve combined with an adaptor unit 212 so that the valve can be removed for repair or replacement without disturbing the pipe connections. The valve body part 10b has inlet and exhaust chambers 14, 16 and a main valve bore 12 as before and also a plane face 213 for co-operation with a similar face 215 on the adaptor unit 212. Ports 108b, 140b in the body 10b register with bores 220, 224 in the unit 212, the parts being secured together by bolts 232. The outlet ports in both parts also register.