SMOKE SENSOR Russian patent published in 1995 - IPC

FIELD: fire signalization systems. SUBSTANCE: a smoke sensor has the body 1, in which the irradiator 2 with the first focusing lens 5 in front of it is mounted in such a way, that their optical axis are coincided, the photodetector 6, the reflector 5 in the form of hollow truncated cone, whose inner surface being mirror one, whose base plane being an elliptical surface and whose geometry axis is coincided with an optical axis of the photodetector and is inclined relative to an optical axis of the irradiator. Such structure of the reflector 5 provides more complete registration of a dissipated irradiation, directed forwards. An angle between the optical axis of the irradiator 2 and the elliptical surface of the cone reflector 5, being parallel with a line, passing through a focal point of the first focusing lens 3, is γ being calculated by the formula where d-diameter of the first focusing lens, f-focal distance of the first focusing lens, a a distance from the irradiation source till the first focusing lens. In a zone of a small circular cross section of the cone reflector 5 the second focusing lens 7 is mounted. The sensor is provided by a spheric reflector 4, whose concave side is turned towards the reflector 5 and whose focal point being in a center of an elliptical cross section of the reflector 4. A distance from the optical axis till the base plane of the spherical reflector 4 is no less, than a half diameter of the first focusing lens 3. Such structure of the smoke sensor is effective in use, simple in production, provides increased range of angles of registration of dissipated irradiation due to using of the spherical reflector 4. A focusing of the irradiation with use of the first focusing lens 3 and predetermined arrangement of the cone reflector 5 allows to eliminated error signals, caused by fault operations. EFFECT: substantially increased sensitivity of the sensor being in a range (0.03-0.05)V/m independently upon a color of the smoke. 1 cl, 1 dwg