Continuous fluid level detector
US4805454A · kind A · utility
Inventor
Key dates
| Filing date | Aug 11, 1986 |
| Grant date | Feb 21, 1989 |
| Priority date | — |
| Expiry date | Aug 11, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F23/246
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A level measuring device comprises an electrical heater, a metallic sheathed thermocouple cable with two thermoelectric elements, a negative temperature coefficient electrical insulant interpositioned between each thermoelectric element and the sheath material of the thermocouple cable such that the thermoelectric elements are not mechanically in contact with each other; an outer cylindrical metallic sheath with one closed and one open end wherein the resistance heater and thermocouple cable are contained; a constant current power supply and a digital millivoltmeter connected to the ends of thermoelectric elements protruding from open end of the outer cylindrical metallic sheath for measuring the loop resistance of the thermoelectric elements; a microprocessor system for computing a length of cable corresponding to the resistance measured using the constant current source and the digital millivoltmeter; and, a power supply for supplying an electrical current to the heater cable. The electrical resistance heater cable supplies thermal energy to the thermocouple cable along its length. When a length of the thermocouple cable becomes uncovered due fluid level changes, the uncovered th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.