Well casing grip assurance system
US4676312A · kind A · utility
119Cited by
10References
12Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 4, 1986 |
| Grant date | Jun 30, 1987 |
| Priority date | — |
| Expiry date | Dec 4, 2006 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B19/07
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A casing grip assurance interlock system connected with the elevator and the spider of a well casing installation apparatus including positioning valves respectively actuated by the elevator and the spider to permit actuating fluid pressure to be admitted to either the elevator or the spider only when the other of the elevator or spider is positioned to firmly grip the well casing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.