US 6,279,875 B1Granted

Gate valve with improved telescoping seat assembly

OwnerVijay R. Chatufaleinventor

Life of this patent

Estimating the term…

Loading patent…

Abstract

A gate valve is disclosed having a telescopingly interfitted seat assembly that fits into a recess in a gate chamber between the gate valve body and the gate. A sealing cavity is formed between two seat elements that form the telescopic connection. A preferably unidirectional seal is disposed therein having two lip seals. The unidirectional seal is preferably oriented to allow leakage for a pressure differential wherein the gate chamber has a higher pressure than the pressure on the opposite side of the seal from the gate chamber. The seal is preferably made of non-permeable material and the material is preferably flexible but non-elastic with little or no memory. Additional such seals may be used for sealing with the gate valve body. In one embodiment, an expansion member is provided for extending into an open end of the seal to expand the two lip seals. An additional bi-directional seal may be provided that is sized to allow leakage when the two seat elements are expanded and to seal when a preferably floating gate compresses one of the telescoping sets seat elements.

Claims36

Dependent claims

A gate valve comprising:

a gate valve body having a gate chamber therein, inlet and outlet passages extending through said gate valve body and being in communication with said gate chamber to define a flow path through said gate valve body, said gate valve body having a recess surrounding said inlet and outlet passages adjacent to said gate chamber;
a telescoping seat assembly in each of said recesses, each said telescoping seat assembly including,
a first seat element defining a receptacle surface therein;
a second seat element defining an outer surface, said outer surface being telescopingly received within said receptacle surface of said first seat element such that said first seat element and said second seat element are each moveable in an axial direction with respect to said flow path;
said first seat element and said second seat element defining therebetween a seal cavity between said receptacle surface and said outer surface;
and
a unidirectional seal element disposed in said seal cavity, said unidirectional seal element having an open end and a closed end, said open end having lip seal surfaces for sealing between said first seat element and said second seat element;
and
a gate positioned within said gate chamber, said gate being moveable within said gate chamber between an open position to allow fluid flow through said flow path and a closed position to prevent fluid flow through said flow path.

6 more elements

Dependencies are inferred from the claim text.