Valve seals are described. An example seal for use in a valve includes a ring-shaped cartridge having a first portion, a second portion opposite the first portion, and a compressible sealing portion between the first and second portions. The first and second portions have respective first and second curved surfaces adjacent a sealing surface of the compressible sealing portion. The first and second curved surfaces enable a flow control member to compress the sealing portion prior to contacting the curved surfaces as the flow control member transitions to a closed position.

A butterfly valve having a disc shutter that engages a gasket whose configuration varies according to the action exerted on its external perimeter by a plurality of pressers sliding in the thickness of the valve body.

A valve seat includes an annular sealing body defining an inner seat surface and an outer seat surface, the inner seat surface defining an annular seating portion configured to seat with a valve member; and a circumferential sealing rib extending circumferentially about the annular sealing body, the circumferential sealing rib defining a gooseneck portion coupled to the annular sealing body and a bulbous portion coupled to the gooseneck portion opposite the annular sealing body.

A valve assembly can include a valve body and a seal ring. The seal ring can be seated in a seal cavity of the valve body. The seal ring can include a base that extends in an axial direction within the seal cavity, a leg that extends from the base, and a foot that extends from the leg. When a disk of the valve assembly is in a closed valve position, a primary seal can be formed between the foot and the disk and a secondary seal is formed between the base and a first wall of the seal cavity. The seal ring can accommodate disk drift at least partly via elastic bending, and can provide disk tracking via lateral movement within the seal cavity.