GB684397A - Improvements in or relating to valves with a passage of annular cross-section - Google Patents

Abstract

684,397. Valves. CULAUD, A., and ATELIERS DES CHARMILIES SOC. ANON. March 31, 1949 [June 4, 1948], No. 8765/49. Class 135. A valve, e.g., for an autoclave, comprises a closure member 4 having a main seating insert 14 adapted to coact with a main seat 18 in the body 1, and an auxiliary seat 22 in the body adapted to be moved to coact with an auxiliary seating surface 23 on the valve member when it is desired to remove the seats 14, 18 for attention. The seat 23 forms part of a piston 17 and a chamber 26 above the piston is connected to the inlet side of the valve or to the atmosphere under the control of a cock 27, the chamber 24 beneath the piston being open to atmosphere through a passage 25. The valve is controlled by a pilot valve 55 which balances the main valve closure member and is actuated by a servo piston 8 supplied with a control fluid through a pipe 9 under the control of a valve (not shown). Inlet pressure acts through a pipe 13 on a small piston 10 to seat the member 4 when the pipe 9 is connected to exhaust. The pilot valve has main seats 49, 52 and auxiliary seats 48, 54, the seat 52 being attached to a piston 61 urged to engage seat 49 by inlet pressure acting through a passage 59. When seat 23 is actuated to engage seat 22, the passage 59 becomes open to the valve outlet hence the auxiliary seats of the pilot valve engage each other and the seats 14 and 18, 49 and 52 may be removed through the outlet after removing a pipe section C. In another arrangement, a pilot valve 62, Fig. 2, is arranged in a conduit 63 which by-passes the main valve and both the main and auxiliary seats 18, 23, respectively of the body are attached to pistons 45, 17, and are movable into and out of contact with the respective seats on the closure member. The closing movement of the closure member is limited by a stop formed by a washer 32a on piston 10, thus permitting the main and auxiliary seats to be moved independently of the force which urges the closure member in the closing direction. In a modification, the servo piston is located on the outlet side of the closure member, and only the main seat in the body is movable, being actuated either by screws accessible from outside the valve or by inlet pressure. In another arrangement, the closure member slides on vanes connected to the walls of the body and supports a cylinder for the servo piston.