Ion type smoke sensor

Details Ion type smoke sensor Ion type smoke sensor

1979-08-23

1980-11-18

Caldwell, Sr., John W.

Communications: electrical

Condition responsive indicating system

Specific condition

250381, G08B 1710, G01T 1185

Patent

active

042348773

ABSTRACT:
In an ion type smoke sensor including a smoke sensor having an internal electrode, an intermediate electrode and an external electrode, and a field effect transistor having a control input terminal connected to the intermediate electrode, a first output terminal connected to the internal electrode and a second output terminal connected to the external electrode, an ion type smoke sensor of this invention comprises an oscillator circuit for generating an oscillating output having a predetermined oscillating frequency; a reference level source for intermittently producing an output signal with a predetermined reference level in response to the oscillating output from the oscillator circuit; and a comparing circuit for comparing a sensing output between the first and second output terminals of the field effect transistor with the reference level from the reference level source to produce a fire sensing signal in accordance with the result of the comparison. According to this invention, an erroneous alarm issuance is minimized as a result of a stable intermittent sensing operation. An operating point for determining the sensitivity of the sensor can be set easily and precisely.

REFERENCES:
patent: 3733596 (1973-05-01), Arima
patent: 3959788 (1976-05-01), Tipton et al.
patent: 4004288 (1977-01-01), Webb, Jr.
patent: 4023152 (1977-05-01), Okuda et al.
patent: 4041479 (1977-08-01), Miyabe
patent: 4081795 (1978-03-01), Ogawa
patent: 4084156 (1978-04-01), Wittlinger
patent: 4096473 (1978-06-01), Sweany et al.
patent: 4123656 (1978-10-01), Kajii
patent: 4163226 (1979-07-01), Ogawa

Affiliated with

Also associated with

Rating

Ion type smoke sensor does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Ion type smoke sensor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ion type smoke sensor will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-600426