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. 05, 1994
Filed:
Jul. 24, 1992
Kanji Ishii, Yokohama, JP;
Hochiki Kabushiki Kaisha, Tokyo, JP;
Abstract
The present invention relates to an improvement of an ionizing smoke sensor having one radiation source and a two chambered structure consisting of an internal ionization chamber housing an internal electrode having a radiation source and defined by an intermediate electrode, and an external chamber where smoke can flow in, defined by an external electrode and irradiated from the radiation source through an opening in the intermediate electrode. Hitherto, in an ionizing smoke sensor having one radiation source and a two chambered structure, there has been a problem in that the giving of misinformation and noinformation occur when a little amount of thread, moisture or dust invades or a current of air flows an internal ionization chamber through an opening and an external ionization chamber. In addition, the electric field in the internal ionization chamber loses its homogeneity because of the opening, hence V-I characteristics preferable for the internal ionization chamber can not be obtained. Furthermore, stable V-I characteristics can not be obtained since hardly any smoke can hardly flow into the internal ionization chamber because of the mesh structure. In the ionizing smoke sensor of the present invention, the above described problems are solved by forming the opening part in the intermediate electrode with a mesh structure having a rate of porosity more than or equal to 50%.