GB940222A - Improvements in fluid control valves - Google Patents

Abstract

940,222. Valves. AUDCO Ltd. April 3, 1962 [April 4, 1961], No. 11938/61. Heading F2V. A hollow guide rod 12, Fig. 1, which extends through a valve seat 11 mounts a composite piston 13 around which is a cylinder 14 connected rigidly or by resilient means to an annular closure member 15 with a resilient seal 16; the cylinder 14 is moved to open or close the flow passage through the seat 11 by supplying pressure through passages 17, 18 in the rod 12 to either side of the piston 13. The cylinder is connected by a cable 19 to a position indicator. The piston 13 comprises an upper annulus 20 fixed to the rod 12 below and which are spring washers 21, and an externally tapered member 22 also fixed to the rod 12 and engaging a number of internally tapered segments 23 with external friction material 24 which is urged into contact with the cylinder 14 by the downward thrust of the washers 21. Below the parts 22, 23 is the lower piston portion 25 mounted for slight axial movement on the rod 12. The segments 23 are moved out of engagement with the cylinder by the portion 25 during unseating of the valve, and, due to the tapered surfaces, when pressure is supplied to the upper end of the cylinder to seat the valve. In a modification, the piston embodies upper and lower parts 29, 30, Fig. 2, both secured to the rod 12 and spaced by a sleeve 31; between the portions 29, 30 are balls 32 coacting with a cylinder step 42. An annular piston 34, which is mounted on the portion 29, carries four rods 35 that extend through a cam ring 36; upon raising the ring 36 the balls 32 enter a space below a tapered cam surface 8 on the ring. Each rod 35 has an abutment 37 in an aperture 38 in the lower portion 30. Springs 39 are disposed between the piston 34 and the cam ring 36. When pressure fluid is supplied to the upper end of the cylinder, the piston 34 is depressed, the rods 35 slide through the ring 36 since the latter is received by the balls 32, and the springs 39 are compressed. When the valve seats the springs 39 urge the ring 36 downwardly and the surface 8 forces the balls 32 into the step 42. When pressure fluid is supplied to the other end of the cylinder it also flows into an annular space 41 and raises the piston 34 and hence the ring 36 so that downward movement of the cylinder causes the step 42 to urge the balls inwardly. Steps 42 may be provided at other places in the cylinder so that the valve can be locked intermediate the open and closed positions. In a further modification, the rods 35, Fig. 4, extend through expanders 43 having a conical cam surface; a pair of arcuate members 45 is also provided each having a pair of abutments between which a number of balls are disposed. Each of the members 45 has a bevelled surface 47 that engages the expander 43 so that the members 45 move laterally as the expanders move vertically.