Abstract: A gate valve sealing unit includes first and second annular seal members that are attached to a main body structure within a passageway that receives and is selectively occluded by a gate. The first and second seal members include first and second rigid mounting hubs to which are mounted first and second annular elastomer sleeves, respectively. Each elastomer sleeve has a continuous lip section and plural axially spaced cavities, the lip sections of the first and second sleeves engaging peripheral margins on opposite sides of the gate when it occludes the passageway and engaging each other otherwise. The first and second mounting hubs include axially outward radial flanges that extend from the respective first and second sides of the main body structure.

Abstract: A gate valve sealing unit includes first and second annular seal members that are attached to a main body structure within a passageway that receives and is selectively occluded by a gate. The first and second seal members include first and second rigid mounting hubs to which are mounted first and second annular elastomer sleeves, respectively. Each elastomer sleeve has a continuous lip section and plural axially spaced cavities, the lip sections of the first and second sleeves engaging peripheral margins on opposite sides of the gate when it occludes the passageway and engaging each other otherwise. The first and second mounting hubs include axially outward radial flanges that extend from the respective first and second sides of the main body structure.

Abstract: A gate valve body member 10 and plastic liner 12 define a flow passage 24 therethrough which communicates with a pair of pipes 34 bolted to the gate body. The liner has a bottom seating surface engageable by the gate 22 and extending from a central point outward to the sides of the flow passage. A top opening recess 54 in the liner 12 receives the gate in a slidable sealing fit. The recess and gate are wider than the flow passage and defining walls of the gate receiving recess terminate at the bottom intermediate the center and sides of the seating surface to provide side sealing and pressure backing support in both directions of flow for a lower portion of the gate and particularly a support below the horizontal center line of the flow passage. The seating surface includes a central arcuate surface portion and straight surface portions joined therewith and extending outwardly to the sides, the bottom edge of the gate being configured to fit the arcuate and straight surface portions.

Abstract: An improved gate valve for effective sealing regardless of the pressure of the fluid of the conduit to which the valve is attached. The gate valve comprises a body (20) having opposing upstream and downstream sides (46, 44). Each side has a conduit-joining surface (72, 73) formed thereon. The body is configured for connection between two axially aligned conduits (24, 25) with each conduit-joining surface abutted against the end of an associated conduit. A resilient liner (27) is attached to the body between the valve gate (32) and the body (20). The liner also covers the portion of the body that defines the port. The liner includes a sealing surface (60) formed thereon. The sealing surface is configured for sealing contact with the portion of the edge surface of the gate that resides within the body when the gate is in the closed position. The gate valve also includes at least one seal ring (62) positioned against the body at the periphery of the port on one side of the gate.

Abstract: This multiplier includes a first link unit in a force transferring relationship with one of an actuator and a device to be actuated. A second link unit is pivotably connected to the first link unit in a force transferring relationship with the other of the actuator and the device to be actuated. At least one spring in a force transferring relationship with at least one of the first and second link units is provided. The first and second link units are disposed between the actuator and the device to be actuated with the first and second link units in cooperation with each other and the spring providing a relatively linearly increasing multiplied output force to the device to be actuated when the actuator is actuated.