Apparatus for measuring depth of a fluid chamber
US4949584A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 8, 1989 |
| Grant date | Aug 21, 1990 |
| Priority date | — |
| Expiry date | May 8, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B17/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The depth of a cavity or chamber (10') is measured by using the chamber as the resonator of an electronic oscillator (24) whose oscillations are coupled to fluid in the cavity by transducers (12, 13). Both the variable-depth main chamber (10') and a reference chamber (117) of fixed depth are measured. Variations in the data obtained from the chambers are caused by factors affecting the velocity of propagation of sound in the fluid. An accurate measurement of the depth of the main chamber is obtained by compensating direct data (at 42) obtained from the main chamber (10'), using, data (at 43) obtained from the fixed-depth reference chamber (117). In one embodiment an inertance orifice (121) is utilized between the two chambers. The fluid inertance of the orifice, together with the compliance of the fluid in the main chamber (10'), form a resonant system whose anti-resonant frequency is a measure of the dimensions of the main chamber. (Inertance is the acoustical equivalent of inductance.)
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.