METHOD AND APPARATUS FOR ADJUSTING SENSITIVITY OF PHOTOELECTRIC TYPE SMOKE SENSOR

• Main Author: HORIUCHI SATOSHI
• Format: Patent
• Language: English
• Published: 27.03.1991
• Subjects: ALARM SYSTEMS; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; ORDER TELEGRAPHS; PHYSICS; SIGNALLING; SIGNALLING OR CALLING SYSTEMS; TESTING

PURPOSE:To facilitate the setting of sensitivity and adjusting operation and moreover, enable the adjusting of sensitivity of a smoke sensor precisely and the checking of operation by providing a condenser lens and a stop on the photodetecting surface side of a photo detector in a smoke detecting section. CONSTITUTION:A cover 82 of a smoke sensor body 1 taken out is removed and a cover 5 is taken off to be replaced with a cover 9 for adjustment. Thereafter, when the sensor 1 is put into operation, a noise light in a photo detecting area L2 a smoke detecting section D is condensed and incident into a photo detector 7 through a stop 95. Here, as the stop 95 is operated to be opened little by little, a quantity of luminous flux passing through an optical path within the stop 95 is increased so that scattered light irradiating the photo detector 7 through the photo detecting area L2 increases. Then, when a quantity of light incident into the photo detector 7 increases to reach a fixed value, the operating state of the smoke sensor 1 is inverted. Or a detection output corresponding to a density of smoke is generated. This enables the adjusting of sensitivity of a smoke sensor 1 yet to be adjusted and the checking for operation of the smoke sensor 1 adjusted from the opening of the stop at this moment.