SMOKE DETECTOR Russian patent published in 2014 - IPC G08B17/10 

FIELD: physics.

SUBSTANCE: smoke detector, having a cover equipped with slits for intake of smoke, a smoke chamber mounted in the bottom part of the cover, having a smoke detection area, which includes a closed lateral enclosure, a radiation source, a photodetector, as well as, below the smoke detection area, a smoke entry area having a bottom and smoke-directing fins, according to the invention, the smoke chamber has a flat annular base, on the perimetre of the top surface of which there is a lateral enclosure; the smoke entry area has a first annular shoulder formed on the bottom surface of the annular base with offset from its outer edge; the bottom is in form of a disc which is deeper than the bottom surface of the annular base, wherein the size and location of said disc are selected such that an annular gap is formed between it and the inner edge of the annular base; the smoke-directing fins are in form of vertical plates which are mounted on the bottom surface of the annular base in a star-like manner such that their outer areas are located on the first annular shoulder, and bottom edges of the inner annular areas are fastened to the bottom; the cover has a flat bottom part, having an outer second annular shoulder and an inner third annular shoulder, which forms an annular groove with the second annular shoulder, and a lateral surface in the bottom part of which there are peripheral slits which form openings for intake of smoke; the fins have incisions under the third annular shoulder, the dimensions and the location of the first, second and third annular shoulders, the mutual arrangement thereof, as well as the mutual position of the smoke chamber and the cover a selected such that, when mounting the smoke chamber into the cover, the third annular shoulder passes through the incisions in the fins, and the first annular shoulder lies in the annular groove with clearance from its bottom and lateral sides.

EFFECT: improved dust protection of the sensor while minimising dependency of its sensitiveness on the direction of smoke.

4 dwg