Method and apparatus for measuring axial and torsional loads on a valve stem
US5684596A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 6, 1995 |
| Grant date | Nov 4, 1997 |
| Priority date | — |
| Expiry date | Mar 6, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L5/0061
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical system for determining the axial load, the torsional load or both on a generally cylindrical member, such as a valve stem in a motor operated valve, includes a first system for producing a test light that is modified by a physical change in the valve stem caused by the load, a second system for receiving the test light and converting the same to a first signal indicative of the physical change, and a third system for converting the first signal to a second signal indicative of the load, preferably by utilizing one or more of the relations defined in Equations 1-3. The physical change in the cylindrical member can be, for example, a diametrical change or a longitudinal change, which can be measured by the first and second systems. The dimensional changes can be related to the axial load according to Hooke's Law or Poisson's relation by the third system when material properties and the geometry of the cylindrical member are known. Similarly, the torsional load applied to the cylindrical member can be obtained by measuring the twist angle between two longitudinally separated planes of the member, and applying a known relation between the twist angle and known geometric and …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.