Sensor device using lamb elastic waves for detecting the presence of a liquid at a predetermined level
US4954997A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 3, 1989 |
| Grant date | Sep 4, 1990 |
| Priority date | — |
| Expiry date | Mar 3, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S367/908
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The sensor device for detecting the presence or absence of a liquid (2) at predetermined level (N) in a tank (1) comprises a transmitter transducer (51; 51'; 61), a receiver transducer (52, 52', 62), and electronic means (100) for processing the signals applied to the transmission transducer and delivered by the receiver transducer. In the vicinity of the predetermined level (N) of the tank (1), the device includes a detection plate (50; 50', 60) having at least one face (58) which comes into contact with the liquid (2) when the liquid reaches that level. The detection plate carries the transmitter transducer which is disposed for locally generating Lamb waves in the plate, and the plate also carries the receiver transducer which is disposed for detecting the presence or the absence of Lamb waves transmitted along the plate. The receiver transducer is connected to a high gain amplifier whose output is connected to the transmitter transducer so as to form an oscillating closed loop, with oscillations in the loop being interrupted when the liquid reaches the predetermined level (N).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.