Transmitter-receiver loop buried metal object locator with switch controlled reference voltage
US4348639A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 18, 1979 |
| Grant date | Sep 7, 1982 |
| Priority date | — |
| Expiry date | May 18, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/108
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Apparatus and method are provided for locating the position, depth, and run of a longitudinal metal object. Specifically, apparatus and method are provided for the tracing of a longitudinal subterranean metal object such as pipes or cables. The apparatus is capable of energizing a subterranean metal object and thereafter detecting the electromagnetic field produced by the metal object with a search loop. The magnitude of a current produced in the search loop is precisely measured whereby the location of the pipe or cable is precisely established. Circuitry is provided to provide high noise immunity to the detection of electromagnetic fields not originating with the metal object. Means are provided to maintain the system sensitivity without relying upon tedious mechanical adjustments.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.