Borehole strain monitor for soft rock
US5048344A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 23, 1989 |
| Grant date | Sep 17, 1991 |
| Priority date | — |
| Expiry date | Oct 23, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L1/10
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A borehole strain monitor for soft rock consisting of a sensing unit, an installation/retrieval provision and a read-out unit. The sensing unit has a U-shaped yoke and is fitted with a vibrating wire transducer. A magnetically coupled variable frequency oscillator determines the point of resonance for the tensioned wire. The resonant frequency is measured with a frequency counter. The sensing unit is used, typically, in boreholes between two and six inches in diameter. The unit is firmly seated in the borehole by means of a pad at one side and a positively guided wedge at the other to bring the unit in contact with diametrially opposed portions of the borehole wall.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.