Importance

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Abstract

Valves of the diverter and isolating types have their ports which are to be opened and closed surrounded by seats each of which is inclined inwardly towards the surrounded port. The hinged blades are surrounded by tips in support of seals of which there are two for each port to be closed. The seals are metallic and resiliently flexible and the seals of each pair are disposed to engage spaced apart, transverse zones of a seat when a blade is operatively positioned to close the surrounded port. As a diverter valve has two ports to be closed by opposite sides of its blade, there are two like but oppositely disposed pairs of seals, one pair for each port. With both types of valves, the seals of a blade are in substantially linear engagement with a seat when the blade is positioned to close the associated port and are in scraping engagement with the seat as the blade moves into and out of that position. In preferred embodiments, each seal and a wing are angled away from the blade tip to which they are attached and towards the port to be sealed. Each seal is held tensioned by the associated wing until the seat is engaged to cause its flexing and the wing is operable to scrape seat encrustments without engaging the seat.

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First Claim