Pittway Corporation

Thomas William Shoaff

Lee D Tice

George Schoenfelder

Jim Wiemeyer

James Fredrick Wiemeyer

Frederick J Conforti

Dragan Petrovic

Kalvin Watson

George A Schoenfelder

A low profile, low volume smoke chamber displaces a light source, such as a light emitting diode or laser diode, and a sensor, such as photodiode or phototransistor, to the exterior of the sensing volume. A symmetrical sensing volume results which can be coupled to symmetrical input/output ports via a generally U-shaped flow path. A two part sensing chamber housing is formed with a lower cylindrical base portion and an upper cylindrical cover portion which slideably engage one another. At least the upper cylindrical portion carries a plurality of grooves for suppression of reflections and collection of dust. An exterior end of the upper portion carries a plurality of spaced apart openings which can be filled with a screen. A reduced sensing volume in combination with a selected screen size produces an acceptable signal to noise ratio and response rate while still excluding insects and other non-smoke related particulate matter.

Miniature photoelectric sensing chamber

An aspirated-type detector includes a housing with an internal ambient condition sensing region and a sensor carried therein. The housing is perforated with ambient atmosphere inflow ports. A fan or similar device lowers the pressure in the internal region thereby producing a positive inflow of adjacent, external ambient atmosphere into the sensing region. Alternatively, the fan can be operated to inject exterior ambient atmosphere into the sensing chamber under positive pressure. The fan can also be modularized. The detector can incorporate control circuitry for supervisory or signal processing purposes.

Aspirated detector

Growing community of inventors

Warrenville, IL, United States of America

Thomas William Shoaff