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.

Date of Patent:
Sep. 05, 1995

Filed:

Mar. 25, 1994
Applicant:
Inventor:

Mikio Mochizuki, Tokyo, JP;

Assignee:

Nohmi Bosai Ltd., Tokyo, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G08B / ;
U.S. Cl.
CPC ...
340589 ; 340587 ; 340584 ; 340508 ; 374 30 ;
Abstract

A heat detector includes an external temperature detector for detecting an external temperature outside the heat detector and an internal temperature detector for detecting an internal temperature inside the heat detector. A microcomputer calculates a temperature difference between the external temperature detected by the external temperature detector and the internal temperature detected by the internal temperature detector. The microcomputer monitors the above-described temperature difference to detect an event in which the temperature difference has remained greater than a predetermined value for a predetermined duration or longer. If the microcomputer detects that the temperature difference has remained greater than the predetermined value for the predetermined duration or longer, the microcomputer outputs an abnormal signal representing that the external temperature detector is abnormal.


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