Coil apparatus mounted on an axially split spool for indicating wall thickness variations of a length of ferromagnetic pipe
US4611170A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 24, 1985 |
| Grant date | Sep 9, 1986 |
| Priority date | — |
| Expiry date | Jun 24, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/10
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus are provided for effecting the inspection of a ferromagnetic element, or piping, and particularly piping that is already installed. The invention incorporates a device for indicating wall thickness of a length of the ferromagnetic element, including means for producing a value of magnetic flux extending longitudinally through a portion of the element. A voltage generating device is disposed in surrounding relationship to the element and is movable axially relative to the length of the element containing the value of the magnetic flux. Means for indicating the voltage generated in the voltage generating means by the value of the magnetic flux also are provided. Preferably, an axially split spool is provided which may be closed in surrounding relationship to an installed pipe. A saturation level of magnetic flux is induced in the pipe by a flexible cable which is wrapped around the spool in a multi-turn configuration and supplied with electrical current sufficient to produce saturation. The spool incorporates in its periphery three axially split pickup coils, the ends of which are brought into interengagement by the closing of the spool around the length of pip…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.