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. 13, 1999
Filed:
Jun. 30, 1998
Applicant:
Inventors:
Ichiro Endo, Tokyo, JP;
Yukio Yamauchi, Tokyo, JP;
Assignee:
Hochiki Corporation, Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G08B / ;
U.S. Cl.
CPC ...
340630 ; 340628 ; 250574 ;
Abstract
The pulse width of a light reception pulse signal a from a light receiving device is detected, and the smoke density is detected based on a total pulse width of pulse widths per unit time period. Alternatively, the smoke density may be detected based on an integrated value of the light reception pulse signal a from the light receiving device per unit time period. Even if the flow rate of the sucked air is varied, the total light reception pulse width value per unit time period is not varied, so that the smoke density can be accurately detected.