Stream-flo Industries Ltd.

Andrew Francis Masson

Tony M Lam

Tianle Guo

Keith David Farquharson

Glen Murray Eleniak

Thomas L Gust

An expanding gate valve and method is provided for bidirectional sealing capability against pressure, whether the direction of pressure is upstream or downstream. The bidirectional annular seat seals against the gate assembly against pressure from the normal wellhead direction, typically upstream. For sealing against pressure in the opposite direction, the seat is formed with an annular recess extending radially outwardly from the central bore of the annular seat so that a flex portion of the seat formed between the recess and the front sealing face of the annular seat at the central bore flexes toward the gate assembly against this pressure. The front face of the bidirectional seat forms a raised annular sealing portion on the flex portion of the seat adjacent the central bore to provide sealing contact with the gate assembly in the expanded condition when the flex portion flexes toward the gate assembly.

Expanding gate valve

A gate valve for controlling fluid flow, with a valve body forming a cylindrical flowbore and a gate cavity intersecting the flowbore to provide opposed openings. Seat pockets formed in the opposed openings may optionally include a metal carrier ring. A non-metallic bridging seal formed as a face seal is provided between the first seal surface of the annular seat element and the seat pocket. The bridging seal bridges any gap formed at the first seal surface such that sealing engagement is maintained across the gap at all times as the gate moves between open and closed positions, while still permitting limited axial movement of the annular seat element. Preferred embodiments of the bridging seal include tongue and groove seals and bridge ring inserts. A secondary seal to the seat pocket may be included as a corner, periphery or face seal, for example as an O-ring, U-ring or wiper seal.

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Edmonton, Canada

Andrew Francis Masson