FLUID FLOW CONTROLLING VALVE HAVING SEAL WITH REDUCED LEAKAGE

摘要

A valve for controlling fluid flow has a housing (230) with a plurality of ports (220). A movable element (250) has a movable surface with an opening, and is capable of moving between (i) a first position in which the opening is aligned to at least one of the ports such that fluid can pass between ports, and (ii) a second position which blocks the passage of fluid between the ports. At least one rim seal (304) encircles each of the ports, each opening, or both. A floating seal (600) is positioned between the movable surface and the housing and is in contact with the at least one rim seal. The floating seal has a passage that aligns with the opening of the movable surface and at least one of the ports when the movable element is in the first position, and a continuous sealing surface about the passage that is sufficiently long to close off the opening of the movable surface as the movable element moves from the first position to the second position, thereby reducing leakage of fluid between the movable surface opening and the ports.