The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 07, 2000
Filed:
Apr. 06, 1998
Endress + Hauser GmbH + Co., Maulburg, DE;
Abstract
Sensing the level of a liquid in a vessel by the pulse transit time technique is done by means of an ultrasonic transducer mounted above the highest-permissible level in the vessel which emits ultrasonic transmission pulses to the surface of the liquid and receives the ultrasonic echo pulses reflected from the liquid surface. The level in the vessel is established from the transit time of the ultrasonic pulses. To detect an overfill when the ultrasonic transducer is immersed in the liquid the decaying output signal of the ultrasonic transducer generated by the ringing of the ultrasonic transducer following the end of the each ultrasonic transmission pulse is analyzed. In this arrangement the fact is exploited that due to the better coupling of the ultrasonic transducer to the liquid than to air the ringing duration is shorter when the ultrasonic transducer is covered by the liquid.