SU628519A1 - Fire alarm - Google Patents

Description

The fire detector is designed to detect fires caused by infrared flame and can be used both in alarm systems and in automatic fire protection systems mainly in refineries, compressor stations, main oil and gas pipelines, in cable tunnels, in the chemical industry. , as well as in various branches of the national economy.

A device is known in which flame detection by a detector is based on the red-blue ratio method from the field of heterochromic photometry and pyrometry, when a divider made of photoconverters sensitive in the red and blue regions of the spectrum due to their selectivity or the use of light filters is used.

In this case, the photoconverter, which is sensitive in the red region of the spectrum, responds only to thermal radiation, and the photoconverter, which is sensitive to

blue region of the spectrum, responds only to light from the G11 source.

The implementation of this method in fire detectors allows one to obtain a high flame selectivity with resistance to solar radiation, which establishes the equilibrium state of the divider.

The disadvantages of the known detectors are the need to amplify the signal, the power of which is limited by the residual resistance of the working photoconverter, snukey sensitivity with an increase in the number of detectors, the lack of sensitivity adjustment and control of the operation of the individual detector.

Claims (3)

The closest to the invention in its essence is a firefighter G2 | out of 20, containing two photoconverters with wavelength-shifted peaks of the spectral sensor. In this case, connected in series through an adjustable resistor, connected to one of the 25 power supply sources, the first key element is connected to the midpoint of the photoconverters. The disadvantage of this device is the insufficient output power required by the amplifier, since the luminous flux of the gas discharge lamp is insufficient for the size of the signal produced by the third photovoltage transducer from the specified stream. The aim of the invention is to increase the reliability of the device. This is achieved by introducing a diode, a second key element, a light guide, the first key element, the element connected in parallel to the first photoelectric converter, which is connected via a diode to a common power supply bus, the average point of the photoelectric converters is connected through serially connected second key element and the LED device output. The drawing is a schematic diagram of the printable detector, the Detector contains a rectifying diode 1, two drivers 2 and 3, a LED 4, two selenisto-cadmium photo resistors 5 and 6 with infrared 7 and blue 8 light filters and a variable resistor 9. Elements 1, 5 6 and 9 are connected in series to an AC power source, dinotor 2 is connected in parallel to the photoresistor 5, key dynistor 3 with LED 4 connected in series between the photoresistors by the signal wire. The detector works as follows. Adjusted by a variable resistor 9 with the maximum allowable background (illuminance), the detector has approximately the same voltage drops on photoresistors 5 and 6 and the midpoint potential between photoresistors 5 and 6 in the wide range of illumination (with its minimum in the dark) is less than the potential of the key dynistor 3 When a flame appears in the field of view of the detector, the photoresistor 5 intensively decreases its resistance, as a result of which the voltage across the photoresistor 6 increases with the potential of the midpoint to A dynistor 3 is connected. When the potential of the dynistor is reached, the latter opens through a low-impedance load (an electromechanical relay in the secondary device), which shunts the photoresistor 6. For the same reason, the voltage drops mainly on the photoresistor 5, thereby opening the second dynistor 2. With the opening of dynistors 2 and 3, a current defined by the resistance- flows through the LED 4 ;. the load. The presence of a rectifying diode is due to the attachment of the detector to a known; Mu device. Claims of Invention Fire Detector containing two photoconverters with wavelength-shifted spectral sensitivity maxima connected in series and through an adjustable resistor connected to one of the power supply busbars, is connected to the midpoint of the photoconverters the first key element that differs in increasing fire safety a detector, a diode, a second epemeitis and a LED are inserted into it, the first key epemuth is connected in parallel to the first phototransducer, which is black of the common bus of the power supply, the middle point is connected via solar cells connected in series and a second key element in a yield of LED devices. Sources of information taken into account in the examination: 1. US patent number 3651442, cl. 338-17, 1969. 2. The patent of Germany No. 1189413, cl. 74a, 33, 1961. 3. Author's certificate number 408350, cl. Q 08 B 17/10, 1974.