Thermally isolated calibration apparatus
US4561285A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 14, 1984 |
| Grant date | Dec 31, 1985 |
| Priority date | — |
| Expiry date | Sep 14, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L25/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus for calibrating a force measuring instrument of the type that includes a force sensitive element submerged in a liquid. The apparatus comprises a magnetic object having a known weight when submerged in the liquid, and an electromagnet. The electromagnet includes a core having a first end that extends beneath the surface of the liquid to a position near the upper surface of the force sensitive element. The electromagnet further includes a coil surrounding a portion of the core, means for energizing and deenergizing the coil, and a thermal insulator surrounding the first end of the core to prevent the core from contacting the liquid and to limit heat flow from the core into the liquid. When the coil is energized, the magnetic object is picked up from the force sensitive element and adheres to the insulator. When the electromagnet is deenergized, the magnetic object falls back onto the force sensitive element for calibration of the instrument. The means for energizing and deenergizing the coil may comprise a pulse generator for producing a high current surge of short duration to lift the weight up off of the force sensitiv e element, and a power supply for producing a low…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.