Device for monitoring a predetermined level of a liquid in a container

US5730025A · kind A · utility

Assignee

• Endress+Hauser Inc. · DE

Inventors

• Igor Getman · Lörrach, DE
• Sergej Lopatin · Lörrach, DE
• Roland Muller · Weiling, DE

Key dates

• Filing date: Oct 16, 1996
• Grant date: Mar 24, 1998
• Expiry date: Oct 16, 2016

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S367/908
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

For monitoring a predetermined level of a liquid in a container an ultrasonic transducer is fitted on the outer surface of the container wall at a measurement point situated at the height of the level to be monitored. The ultrasonic transducer contains a piezoelectric element which generates, when excited by an alternating voltage pulse having a given transmission frequency, an ultrasonic transmission pulse which is transferred via a diaphragm to the container wall and which converts ultrasonic vibrations transferred from the container wall to the ultrasonic transducer into electrical reception signals. The diaphragm comprises on the side facing the container wall protuberances which adjoin the container wall. Between the diaphragm and the container wall a coupling layer is arranged, the thickness of which is determined by the height of the protuberances. As a result of this the formation of a layer of air between the diaphragm and the container wall is prevented and a jump in impedance avoided so that a good acoustical coupling exists between the diapragm and the container wall.