Temperature measuring apparatus
US4095469A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 11, 1977 |
| Grant date | Jun 20, 1978 |
| Priority date | — |
| Expiry date | Mar 11, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01K7/36
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus for measuring the temperature of a metallic body in a non-contact maner includes an electronic circuitry for measuring a change in the impedance of a detecting coil arranged oppposite to the metallic body. The electronic circuitry comprises an operational amplifier, a negative feedback circuit with adjustable feedback factor, a positive feedback circuit, an oscillator, a phase shifter circuit and a synchronous detection circuit. The change in the impedance of the detecting coil is caused by the effect of eddy current produced by the application of alternating field to the metallic body, and this impedance change is dependent on change in the temperature of the metallic body. By adjusting the negative feedback factor .beta..sub.N of the negative feedback circuit and the phase angle .theta. of the phase shifter circuit in the electronic circuitry, the relationship between the distance measured between the detecting coil and the metallic body and the measured output level, the temperature measuring sensitivity relative to the temperature of the metallic body and the temperature measuring sensitivity relative to the measuring distance can be determined as desired.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.