Abstract: An all metal gas metering valve is used in high vacuum installations in the range of 10.sup.-9 Torr. 1/sec. to 100 Torr. 1/sec. relative to helium and 20.degree. C. ambient temperature. An axially extending tubular member forming a part of the valve housing contains a rotationally symmetrical valve body. A bushing laterally encloses at least an axially extending part of and is welded to the tubular member around two welded seams spaced apart in the axial direction of the tubular member. A pressurized medium can be charged into the joint between the inside surface of the bushing and the outside surface of the tubular member and limited by the welded seams. The pressure acting on the tubular member constricts its cross-section and reduces the space between the side surface of the tubular member and the valve body. Initially, the space between the valve body and the tubular member can be kept very small so that a wide adjustment range is available by varying the pressure acting on the tubular member.

Abstract: Opening and closing of a fluid flow path is controlled by a valve closure member which consists of both a sealing plate and a counter element and which is moved within its own plane to open and close the valve assembly by a crank rod. Spreading elements are arranged between the sealing plate and the counter element tending to urge these members apart and the crank rod mechanism includes a slide member which is arranged to move within a guide slot in the sealing plate and to also engage a circumferential edge of the counter element so that during closing movement of the sealing plate by engagement of the slide member in the guide slot, the slide member may also extend to engage the circumferential edge of the counter element to rotate the counter element relative to the sealing plate in order to place the spreading elements in position to apply a sealing force between the sealing plate and counter element.

Abstract: In a high-vacuum closure, a metallic sealing ring is positioned between a first and a second sealing surface. The sealing surfaces are each formed of a metallic surface of revolution and are coaxially arranged. When the sealing surfaces are moved between the open and closed positions, the sealing ring rolls on the sealing surfaces. The sealing ring is shrunk on one of the sealing surfaces for securing it in place.

Abstract: A pneumatic actuator in which a piston and a cylinder define an annular gap therebetween axially connecting two portions of the cylinder cavity otherwise separated by the piston. When compressed air is admitted to one of the cavity portions, an O-ring in an annular groove of the cylinder wall is expanded by the compressed air and seals the gap, and the piston is moved against the restraint of a strong compression spring. When the air backing the O-ring is vented, the air pressure in the cylinder drives the O-ring back into the groove, and air thereafter escapes quickly from the one portion of the cavity through the gap and into the other cavity portion which is open to the atmosphere. The resulting quick movement of the piston by the expanding compression spring is transmitted to a device outside the cylinder for operating the same.

Abstract: A gate value having a sealing plate carried by a moveable element which through the coaction of a series of balls presses the sealing plate into a flow preventing position.