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AssigneeGeneral Signal Corporation
InventorsSung Chuel Lee, Vaclav Oldrich Podany, Hilario Simoes Costa
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Smoke detection apparatus including a pair of photoelectric cells which receive illumination in a predetermined ratio from a very low level light source. An improved simulating device is included for the purpose of testing the correct functioning of the alarm system connected to a sensing circuit formed by the photocells. The effects normally produced by smoke present in a chamber are simulated by selectively directing light from an auxiliary light source onto the sensing or "reflected" cell in the sensing circuit. In addition, a specially designed and constructed sensor head is provided for avoiding discrepancies in the placement of the critical elements; moreover, improved flow of any smoke present is promoted by the specific geometry of the sensor head. Also, discrepancies between the desired and actual ratio of illumination received by the respective photocells can be readily adjusted for electrically, and the light ratio between photocells can be changed by suitably adjusting the degree of illumination received by the direct cell.
In a smoke detection apparatus in which there is included a housing enclosing a smoke detector chamber, a main light source mounted within the housing and a photocell device arranged within the housing for receiving substantial light from said main light source only when such light is scattered by smoke entering such chamber, the improvement which comprises a smoke effect simulating means, said means including an auxiliary or secondary light source, and means for selectively directing light from said auxiliary source onto said photocell so as to substitute for said light scattered by smoke, thereby to simulate the effect of the presence of smoke in said chamber.
Dependencies are inferred from the claim text.