Apparatus for monitoring the level of liquid by resistive wire
US4513616A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 27, 1982 |
| Grant date | Apr 30, 1985 |
| Priority date | — |
| Expiry date | Sep 27, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F23/246
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A hot-wire level detecting apparatus includes a micro-processor which registers a look-up table of digital level values associated with digital values of a differential parameter representing the change in the voltage or current in the hot-wire probe. The micro-processor controls a switch for initiating the application of power to the probe. In one embodiment a constant voltage supply is connected across the emitter and collector of a transistor with the probe in the emitter circuit and a resistor in the collector circuit. The voltage across the resistor, measured at switch-on and after a period for stabilization, is fed to the micro-processor by an analog-digital converter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.