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:
Jun. 19, 1984
Filed:
May. 17, 1982
Applicant:
Inventor:
Robert E Johnson, Pembroke, MA (US);
Assignee:
Pyrotector, Inc., Hingham, MA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G08B / ;
U.S. Cl.
CPC ...
340629 ; 250381 ;
Abstract
An ionization type smoke detector (10) includes a chamber having a measuring electrode (12), the voltage on the measuring electrode being a function of the concentration of smoke in the chamber, and further includes a comparison device (A3) for comparing the voltage measured on electrode (12) at two different times, and an output device (K) for producing an output signal if the voltages differ by a predetermined value.