Ultrasonic sensor with continous and demand self-test for liquid and dry product level measurement
US5808200A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 25, 1997 |
| Grant date | Sep 15, 1998 |
| Priority date | — |
| Expiry date | Aug 25, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/102
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An ultrasonic sensor having a support structure of first and second walls with a gap of fixed distance therebetween. A piezoelectric element for transmitting and receiving ultrasonic energy is bonded to the inner face of one of the walls and the energy transmitted across the gap is reflected from the other wall back to the element. Two timing windows are set, one for the time of energy transmission across the gap with liquid present and the other with the gap being dry. The received energy at the time of the window indicating the dry gap condition is used as a self-test signal to check element dis-bonding. In a sensor with two elements, one bonded to each of the support walls, one element serves as the transmitter and the other as the receiver.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.