Apparatus and method for testing the thickness of the wall of a moving tube leaving an extruder
US4157503A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 21, 1977 |
| Grant date | Jun 5, 1979 |
| Priority date | — |
| Expiry date | Mar 21, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/107
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus for testing the wall thickness of a moving tube of plastics or other electrically non-conducting material being produced by an extruder, comprises an electrically conductive measurement body arranged in the moving tube, a ferromagnetic holding member which is arranged in the tube within effective range of a holding magnet located outside the tube and which has a tie connection to the measurement body to locate the measurement body axially within the effective range of a measuring sensor located outside the tube. The holding member and the measurement body may be introduced into the tube through a channel in the extruder head, shot into the tube from a forward position, or inserted through an aperture cut in the tube wall.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.