A sealing apparatus includes a moveable seal holder with a cavity and includes a seal assembly disposed at least partially in the cavity. The seal assembly includes a resilient seal member including a fluid-facing end with a fluid-facing end surface, and the seal assembly includes an actuator plate configured to reciprocate between a first and a second position relative to the protective plate. The first actuator plate includes a fluid-facing end surface and a first camming surface. The seal assembly further includes a first protective plate disposed between the seal member and the first actuator plate. The actuator plate is configured to compress the seal member and to move the fluid-facing end surface of the seal member outward from a resting position when the actuator plate is in the second position.

A slide valve having a valve disc that is slidably movable between a fully-retracted fully-open position and a fully-extended fully-closed tight shutoff position by an actuating stem. The actuating stem is flexibly coupled to the valve disc. The valve disc is selectively modulated between the fully-extended fully-closed tight shutoff position and a partially-retracted non-tight shutoff position to prevent sticking of the valve disc in the fully-extended fully-closed tight shutoff position.

A slide valve having a valve disc that is slidably movable between a fully-retracted fully-open position and a fully-extended fully-closed tight shutoff position by an actuating stem. The actuating stem is flexibly coupled to the valve disc. The valve disc is selectively modulated between the fully-extended fully-closed tight shutoff position and a partially-retracted non-tight shutoff position to prevent sticking of the valve disc in the fully-extended fully-closed tight shutoff position.

A gate valve includes a valve body and a valve cover. The valve body includes a first opening, a second opening, a third opening, a flow passage from the first opening to the second opening, and a gate channel from the flow passage to the third opening. The gate channel has a central longitudinal axis and a ridge defining a perimeter of the third opening. The valve cover can fit over the third opening and, under force on the valve cover, exert a clamping force on the ridge. The clamping force has a first force component perpendicular to the central longitudinal axis and a second force component parallel with the central longitudinal axis. The first force component of the clamping force is toward the gate channel. The ridge includes a first surface configured to mate with a first surface of the valve cover.

A valve gate may include a threaded rod, a nut engaged with the threaded rod, a movable body mounted on the threaded rod, a seal, a pair of levers, and first and second housing components that at least partially enclose the other components. The threaded rod can be turned to drive translation of the nut and the movable body along the threaded rod. Translation of the movable body along the threaded rod can drive rotation of the levers outward away from the threaded rod, and rotation of the levers can force the seal to expand outward from the threaded rod. Such expansion can force the seal into engagement with an inner surface of a pipeline.

A ring base member of a disc seat ring is fixed to a valve disc using a bolt. The valve disc is formed of a first austenitic stainless steel containing 17.0% by mass to 21.0% by mass of Cr and 8.0% by mass to 13.0% by mass of Ni. The ring base member is formed of a second austenitic stainless steel containing 17.0% by mass to 20.0% by mass of Cr and 8.0% by mass to 15.0% by mass of Ni.

A system includes a split gate valve with first and second gate sections coupled together and configured to move together within a cavity of the split gate valve between an open position and a closed position. The split gate valve includes a rolling actuator to reduce friction and to convert a rotational input into a linear motion to move the first and second gate sections between the open and closed positions. The split gate valve also includes at least one expansion bar configured to bias the first and second gate sections from one another to seal against opposite seats of the split gate valve, wherein each expansion bar includes a spring mechanism configured to compress upon moving the first and second gate sections into and beyond the closed position to prevent buckling of the expansion bar.

A vacuum slide gate valve with a drive unit that is formed in such a way that a closure plate, by displacement of at least one valve rod along a longitudinal axis, is displaceable from an open position into an intermediate position, and, by displacement of said valve rod along a transverse axis running at right angles to the longitudinal axis, is displaceable from the intermediate position into a closing position. The valve rod is rigidly connected to a sliding part, which is guided between a first position and a second position parallel to the longitudinal axis, and between the second position and a third position parallel to the transverse axis. A displacement member is mechanically coupled to the sliding part via an inclined connection to displace the sliding part from the first position into the second position and from the second position into the third position.

A ring base member of a disc seat ring is fixed to a valve disc using a bolt. The valve disc is formed of a first austenitic stainless steel containing 17.0% by mass to 21.0% by mass of Cr and 8.0% by mass to 13.0% by mass of Ni. The ring base member is formed of a second austenitic stainless steel containing 17.0% by mass to 20.0% by mass of Cr and 8.0% by mass to 15.0% by mass of Ni.

A valve having a closure member which is pressed against a valve seat in a closed position and closes an opening, and having a first valve drive for moving the closure member along a first movement path back and/or forth between a maximum open position and an intermediate position, and having a second valve drive for moving the closure member along a second movement path back and/or forth between the intermediate position and the closed position. The first movement path and the second movement path are arranged in an angled manner with respect to one another. The valve additionally includes at least one locking device with at least one locking body which interacts with at least one inclined surface and/or comprises at least one inclined surface, wherein the locking body is movable relative to the closure member along a third movement path between a locking position and a releasing position.