Capacitive thickness gauging for ungrounded elements
US3990005A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 3, 1974 |
| Grant date | Nov 2, 1976 |
| Priority date | — |
| Expiry date | Sep 3, 1994 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/087
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A system for capacitively gauging distance to an element which is not in a low impedance path to ground. The gauging system operates to provide an indication of distance with the potential on the element at a defined level, typically ground. Several embodiments are presented for making this measurement. A first operates to measure distance at periodic instances when the defined potential exists. A second embodiment uses phase opposite excitation to produce a defined potential at the element either by specific placement of the element or through a feedback control over element potential. The system of the present invention may be adapted for use in capacitive thickness measurement on an ungrounded or highly resistive element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.