Abstract: A double sealing valve includes a power cylinder having a driving axle, a valve body formed of a first and a second valve members, and a seal plate assembly within the valve body. Therein, the first valve member has an axle bore for the driving axle to pass through, and the second valve member has two valve holes oppositely disposed. The seal plate assembly has a driving frame connected to the driving axle, with plural roller assemblies disposed around the driving frame. The seal plate assembly has two seal plates disposed between two faces of the driving frame and the valve body, respectively. Each seal plate has plural driving grooves corresponding to the roller assemblies. The driving axle drives the seal plate assembly to seal the valve holes, with a sealing force produced therebetween by use of the roller assembly and the driving groove.

Abstract: A vacuum valve including a valve housing two valve openings, a closure member having two closure plates, a transverse drive unit for adjusting the closure member between an open position and an intermediate position where the closure plates cover the valve openings, a first longitudinal drive unit for adjusting the closure member between the intermediate position and a first closed position, and a second longitudinal drive unit for adjusting the closure member between the intermediate position and a second closed. Each longitudinal drive unit includes a plurality of actuating elements which are guided into the vacuum area of the valve housing. These actuating elements are adjustable by driving elements between a retracted, passive position where their actuating ends are raised from the closure member and an advanced, active position where their actuating ends are pressed against the closure member and press the respective closure plate against the respective valve seat.

Abstract: Apparatus and methods for sealing a parallel expanding gate valve are provided using upper and lower wedges separate from and located between the gate segments. The gate segments are symmetrical with respect to each other and have inner upper and lower tapered surfaces. Inclined surfaces on the upper wedge press the inner upper tapered surfaces of the gate segments. The inner lower tapered surfaces of the gate segments also press against inclined wedging surfaces on the lower wedge. This wedging action forces the gate segments outward with respect to each other and with substantial force against sealing assemblies to close and seal the gate valve.

Abstract: A large diameter gate valve uses a radially directed fluid pressure loaded all metal seal formed by engaging and disengaging a fixed and a moveable seal element. The fixed element is formed of a circular flange which contains a pressure chamber with a deformable wall, and is mounted to the valve body. The moving seal element contains an annular recess which mates with the circular flange, and is carried on a moveable sub-frame which moves on a frame fixed in the valve body. The valve opening defines an axis in a first direction, and the sub-frame moves through the valve body in a second direction which is substantially perpendicular to the first direction. The sub-frame and moveable seal element move in the second direction until the moveable element reaches a stop mounted in the valve body at which position the moveable element is aligned with but spaced apart from the fixed element.