Pittway Corporation

Stephen L Siegel

Philip J Burnstein

George A Schoenfelder

George R Pariza

James S Slater

An outer electrode for a combustion products detector comprising a cylindrical body including a plurality of first slats alternating with a plurality of second slats, the first slats being segments of a first surface of revolution, the second slats being skewed from a second surface of revolution having a different diameter from the first surface of revolution.

Outer electrode with improved smoke entry

A self test circuit for a combustion products detector automatically periodically tests whether the sensitivity of the sensor is in a predetermined range between minimum and maximum sensitivities. Transistor switches selectively connect different test impedances across the sensor for respectively simulating two amounts of combustion products, one of which is slightly less than the amount corresponding to the maximum sensitivity level and the other of which is slightly greater than the amount corresponding to the minimum sensitivity level. If the sensor either produces a smoke output signal in response to the first test or fails to produce an output signal in response to the second test, then the smoke alarm is actuated after the tests are completed to produce a unique fault signal, the alarm annunciator being inhibited during the test.

Self-testing combustion products detector

The contact connects a circuit element (such as a piezoelectric transducer) to a circuit (such as an oscillator which drives the transducer). The contact comprises a body, an ear which is mechanically and electrically connected to the circuit, and a pair of bifurcated fingers which springingly electrically engage the circuit element. Several such contacts may be used to connect different portions of the circuit to corresponding portions of the circuit element.

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Hanover Park, IL, United States of America

Stephen L Siegel