Downhole cut-off valve used for cementing
US5957197A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 2, 1997 |
| Grant date | Sep 28, 1999 |
| Priority date | — |
| Expiry date | May 2, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/7869
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A downhole cut-off valve used for cementing a casing string, comprising: an outer hollow body, having a top end connected at the lower end of the casing string, an inner hole, an inner surface and a projecting shoulder forming on the inner surface and extending inwardly; an inner hollow body, arranged slidably in said outer hollow body and having an inner hole, a wall with a plurality of through holes and a projection forming on the wall and below the through holes and extending outwardly, the projection being adapted to fit with the projecting shoulder of said outer body to define a preliminary position of said inner body with respect to said outer body; the longitudinal positions of the through holes and the projection being arranged in such a manner that the projecting shoulder of said outer body is located therebetween when said inner body is placed in said outer body and will at least partially cover the through holes in response to the movement of said inner body; a relief member, blocking the upper end of the inner hole of said inner hollow body and releasing automatically to expose the upper end of the inner hollow body when necessary; an adjusting member, arranged in the l…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.