Overflow valve of drill string
An overflow valve of a drill string is described comprising a hollow body with side ports, a seat, a shut-off element fitted in the hollow body, characterized in that the shut-off element is in fact an elastic sleeve fitted in the hollow body with an upper end of said elastic sleeve being the first one on the way of drilling fluid flow, and said elastic sleeve being positioned within said hollow body so as to form a gap there between, said elastic sleeve being adapted for expanding from a normal state to a second state upon drilling fluid flow there through, wherein in the second state the side ports are closed by said elastic sleeve and a lower end of said elastic sleeve positioned below the side ports is placed in contact with the seat which is part of the inner surface of the hollow body, said elastic sleeve including an expansion enhancer provided at the lower end of the elastic sleeve in an area of the seat.
- Assignee:
- IMS; EDB-93-107619
- Patent Number(s):
- US 5228526; A
- Application Number:
- PPN: US 7-655432
- OSTI ID:
- 6301749
- Resource Relation:
- Patent File Date: 23 Jun 1989
- Country of Publication:
- United States
- Language:
- English
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