| 摘要 |
1,073,998. Valves. VARIAN ASSOCIATES. Sept. 16, 1965 [Sept. 30, 1964], No. 39636/65. Heading F2V. A vacuum leak-valve with a two-part stainless-steel body 12, 13, Fig. 1, has a lift-type closure-member at one end of a spring-loaded piston 16, which member is formed from, e.g., sapphire or carbide with an optically-smooth closure-surface. The piston 16 is connected to the body by a diaphragm 60 welded therebetween. The valve seat 20 consists of a threaded stainless-steel retaining-sleeve (38, Fig. 2, not shown), a copper gasket (21) forming an annular tapered or curved seating-surface and a stainless steel collar (39), the interengaging surfaces of which are crushed during assembly to provide a vacuum-tight seal. The piston 16, Fig. 1, is moved exponentially when the valve is nearly closed, very fine control of valve movement being effected by a screw 52 through an actuator 22 embodying a rod 36. with a ball at each end; coarse adjustment is done by a screw 50 threaded into a handle 48 pivoted about a rod 49. The fine-adjustment screw 52 has locking means. The valve may have to be baked to drive-off absorbed vapour when used with very small leak rates. |
