SU1462385A1 - Smoke-actuated fire alarm - Google Patents

Abstract

The invention relates to a fire alarm technique and can be used in fire protection to detect fires at an early stage in the appearance of smoke aerosols. The aim of the invention is to increase the functional reliability of the detector. The detector contains a receiving chamber 1, which serves to protect the optical elements from mechanical damage caused by external lighting, and has an internal light-absorbing coating. The photodetector 3 detects the luminous flux scattered by smoke particles. The light source 2 creates a predetermined radiation flux in the inner cavity of the receiving chamber 1. The thermosensitive element 4, in the form of an opaque screen, is made of thermal destruction smoke-generating material, which ensures stabilization of the threshold sensitivity of the detector when the ambient temperature changes, triggering the detector at a certain temperature in the absence of smoke, as well as to eliminate illumination of the photodetector 3. Additional luminous flux created by aerosol particles of the sensing element 4, compensates for the sensitivity of smoke detectors that are typical of smoke detectors when the temperature rises. 1 il. with (L O) N9 00 00 ate

Description

The invention relates to an automatic fire alarm and can be used as a smoke detector at facilities associated with the manufacture, processing, storage and transportation of fire hazardous substances and materials.

The purpose of the invention is to increase (the functional reliability of the detector

The drawing shows a diagram of a smoke detector, a smoke detector sparks a receiving chamber 1, a light source 2 | installed outside the field of view of the photo receiver 3, and a heat sensor “brfi element A in the form of an opaque screen from a thermal destruction panel that expands material. The receiving chamber ipa 1 serves to protect the optical:; Elements from mechanical damage, the effects of external illumination and | has an internal light absorbing cover; the Photodetector 3 provides for the registration of the luminous flux of diffuse smoke particles,

The light source 2 creates a predetermined radiation flux in the inner cavity of the receiving chamber 1, the thermosensitive element 4 is made in the form of an opaque screen made of thermal destruction smoke-generating material, which ensures the stabilization of the threshold sensitivity of the detector when the ambient temperature changes from temperature with no smoke. In addition, the thermosensitive element 4 is designed to determine that the radiation of the source 2 of the light falls directly on the FS sensor 3,

In the absence of smoke particles, the light source 2 creates in the receiving chamber 1 a predetermined luminous flux, which falls on the inner surface of the receiving chamber 1 and is absorbed.

When the temperature rises, the temperature-sensitive element 4 begins to decompose with the release of smoke. The rate of release of aerosol particles from the smoke-generating material increases with temperature. The thermosensitive element 4 is located in the center of the light flux of the source 2, therefore all aerosol particles released from the smoke-generating material

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The rial enters this luminous flux and scatters the eroj part of the scattered light that falls on the photodetector. 3 The additional luminous flux created by the aerosol and particles of the material of the temperature-sensitive element compensates the drop in sensitivity typical of smoke detectors during temperature.

By appropriate selection of the smoke-generating material and the dimensions of the temperature-sensitive element 4, it is possible to achieve a constant sensitivity of the detector with increasing temperature.

At a certain temperature, the amount of aerosol particles formed by the smoke-forming material of element 4 exceeds the threshold concentration, the detector generates a fire alarm output signal that the temperature exceeds a certain value.

In case of a fire accompanied by the appearance of smoke in a controlled environment,

the particles penetrate into the receiving chamber 1, enter the luminous flux of the light source 2 and, dissipating it, create the luminous flux perceived by the photo-receiver 3,

When the temperature rises, the diffused luminous flux from the smoke produced during a fire is summed with the diffused luminous flux from aerosol particles extracted from the smoke-forming material of the thermal element. Thus, at elevated ambient temperatures, the smoke detector is triggered by aerosol particles from the source of fire and from the smoke-forming material of the temperature-sensitive element 4, which compensates for the drop in sensitivity typical of smoke detectors when the temperature rises.

The smoke-forming properties of materials are one of the most stable parameters in nature and do not depend on almost any environmental factors. This ensures a reduction in the error threshold of the detector when exposed to the environment, which increases the reliability of its operation,

Silicone rubber, celluloid, polystyrene, polyvinyl chloride polyurethane can be used as a smoke-generating material. The addition of light-absorbing fillers (carbon black, XC-1177 enamel, etc.) provides the screen opacity,

the smoke generating material greatly simplifies and cheapens the device

Claims (1)

Invention Formula A smoke detector, a light source containing a receiving chamber; mounted out of sight field The device does not have a moving photoelectric element, an opaque screen and cops, which increases the reliability of its operation due to the absence of possible thermosensitive element, characterized in that, with failures and damage of these elements during operation. In addition, the implementation of an opaque screen of thermal destruction In order to increase the functional integrity of the device, the opaque screen is made of thermo-destructive smoke-forming material and is a temperature-sensitive element. the smoke generating material greatly simplifies and cheapens the device Invention Formula  photodetector, opaque screen and thermosensitive element, characterized in that, with photodetector, opaque screen and In order to increase the functional integrity of the device, the opaque screen is made of thermo-destructive smoke-forming material and is a temperature-sensitive element.