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:
Jul. 04, 1978
Filed:
Dec. 16, 1976
Applicant:
Inventor:
Trygve Botnen, Nacka, SE;
Assignee:
Svenska Rotor Maskiner Aktiebolag, Nacka, SE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G08B / ;
U.S. Cl.
CPC ...
340589 ; 165-5 ; 165 11 ; 340599 ; 340 57 ;
Abstract
A fire detection apparatus in a rotary regenerative air preheater comprises a plurality of temperature sensitive detectors which produce an electrical signal, and means for differentiating the electrical signals from the detectors. The differentiated signals are passed through a low pass filter having a large time constant and are then fed to a comparator which actuates a signalling device when the low pass filter output signal exceeds a predetermined value.