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:
Dec. 24, 1991
Filed:
Jan. 31, 1991
Henry Fluhrer, Nuremburg, DE;
Erwin Potthof, Rothenbach, DE;
Diehl GmbH & Co., , DE;
Abstract
A circuit arrangement for the control of a ventilator, especially for a stream or vapor vent hood which is located above a cooking range, in dependence upon steam or vapor clouds which are drawn towards the ventilator. An ultrasonic transmission path having an ultrasonic transmitter and an ultrasonic receiver is located in front of the ventilator, with a receiving circuit demodulating the signal which appears at the ultrasonic receiver; wherein an evaluating or sample-and-hold circuit evaluates any fluctuations in the input signal encountered over a period of time and which are based on the presence of steam or vapor clouds in the ultrasonic transmitting path, and counts these signals within a time frame, and wherein a comparator circuit compares the result of the count with preset values and, in accordance therewith, activates the ventilator.