Method and apparatus for measuring cross sectional area and weight per unit length of elongated, conductive material by magnetic field displacement
US4083002A · kind A · utility
Inventor
Key dates
| Filing date | Feb 17, 1976 |
| Grant date | Apr 4, 1978 |
| Priority date | — |
| Expiry date | Feb 17, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01G9/005
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus is disclosed whereby a solenoid coaxially surrounding an elongated electrically conducting material generates a radio frequency magnetic field of such a frequency that the material within excludes or displaces magnetic lines of force therefrom. One or more search coils are mounted coaxially within the solenoid, but outside of the material. By comparing the signal induced in the search coils when the material is present with the signal induced in the search coils when the material is absent, the outer cross sectional area of the material may be measured by measuring magnetic field exclusion or displacement, from the search coil andfrom this data, weight per unit length of solid material may be inferred. Furthermore, a pattern of deformations on the material may also be inferred, when the material is moving at known speed, from any high frequency modulation of the signal picked up by the search coil. When the mean mass per unit length of hollow elongated materials is known the mean wall thickness may be inferred.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.