Downhole cable tension measuring apparatus
US4265110A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 25, 1979 |
| Grant date | May 5, 1981 |
| Priority date | — |
| Expiry date | Jun 25, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L5/103
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Downhole cable tension measuring apparatus according to the invention is connected between a cable and well-logging apparatus suspended from the cable in a borehole. A rod is placed between the cable and the well-logging apparatus so as to elongate elastically under the effect of cable tension. A sleeve, fixed at one end of the rod, surrounds the rod. A transformer, the primary of which is wound on the rod, the secondary of which is wound on the sleeve, detects the relative longitudinal displacement of the other end of the rod with respect to the sleeve. Two primary windings displaced on the rod are alternately excited to generate two signals in the secondary coil in order to correct temperature drifts of the circuits. The rod and sleeve are made of the same metal so that each of them will elongate similarly as a function of temperature. The apparatus is placed in a pressure-balanced oil-filled chamber.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.