Backseat assembly for an expanding gate valve
First Claim
1. A gate valve comprising:
- a housing having a chamber with a flow passage therethrough and a stem-receiving bore transverse of said flow passage;
an expanding gate member including first and second segments reciprocable in said housing transversely of said flow passage, said first and second segments having wedging surfaces causing said gate member to expand as said first segment travels axially away from said second segment;
a stem member connectable at one end to said first segment and connectable at another end to a means for reciprocating said stem;
said housing having an annular seat about said bore facing said chamber and a stop member for engaging said second segment;
a sealing member slidingly disposed about said stem and supported by said first segment;
a biasing member disposed between said first segment and said sealing member for biasing said sealing member away from said first segment;
whereby upon said stop member engaging said second segment, said stop member limiting the travel of said second segment allowing continued travel of said first segment for said expanding gate member, said biasing member biasing said sealing member into sealing engagement with said annular seat to seal said stem with respect to said housing.
2 Assignments
0 Petitions
Accused Products
Abstract
A backseat assembly for an expanding gate valve includes a sealing member slidingly disposed about the stem and a biasing member biasing the sealing member away from the gate. Upon the gate and segment traveling to the open position of the valve, the segment engages the valve housing and stops its further movement. The stem and gate continue their travel with the sealing member engaging an annular seat on the housing for sealing between the stem and housing. The sealing member includes an annular resilient sealing member which initially engages the annular seat of the housing. The biasing member places a preload on the sealing member such that upon engagement of the annular seat by the sealing member, there is initial sealing force placed on the sealing engagement. The fluid pressures within the valve chamber add an additional sealing force to the sealing member.
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Citations
15 Claims
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1. A gate valve comprising:
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a housing having a chamber with a flow passage therethrough and a stem-receiving bore transverse of said flow passage; an expanding gate member including first and second segments reciprocable in said housing transversely of said flow passage, said first and second segments having wedging surfaces causing said gate member to expand as said first segment travels axially away from said second segment; a stem member connectable at one end to said first segment and connectable at another end to a means for reciprocating said stem; said housing having an annular seat about said bore facing said chamber and a stop member for engaging said second segment; a sealing member slidingly disposed about said stem and supported by said first segment; a biasing member disposed between said first segment and said sealing member for biasing said sealing member away from said first segment; whereby upon said stop member engaging said second segment, said stop member limiting the travel of said second segment allowing continued travel of said first segment for said expanding gate member, said biasing member biasing said sealing member into sealing engagement with said annular seat to seal said stem with respect to said housing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification