SU999078A1 - Fire alarm starting device - Google Patents

Description

(54) FIRE SIGNAL AND STARTING DEVICE

The invention is intended to detect flames under conditions of high background noise and can be USED in automatic fire extinguishing installations. Known fire alarm start device containing two light fire sensor, the outputs of which are combined according to the trigger 1. The disadvantage of this fire-fighting signal-starting device is low reliability. It is also known fire alarm. a starting device containing two sensors, a switch, an amplifier, a driver, two relays, a threshold unit, an AND element, a key, and a combined signal and starting unit 2 J. The disadvantages of the known device are low reliability and speed. The scope of the invention is to increase the reliability and speed of a fire alarm trigger device. The goal is achieved by the fact that in the fire signal and starting device; An array containing two sensors, a threshold unit, a switch, a display unit, a starting unit and an AND element, two pulse extenders, a trigger OR element, whose inputs are connected to the sensor outputs and trigger inputs, and an output are entered to the first input of the switch, the second input is entered. which is connected with the withdrawal of the outputs of the trigger, the outputs of which are connected to the display unit and through pulse extenders connected to the inputs of the terminal I. The output of which is connected to the third input of the switch, the output of which through the threshold unit is connected to Uskov unit. The drawing shows a diagram of a fire alarm starting device. The device contains sensors 1 and 2, the element OR 3, the trigger 4, the expanders 5 and 6, the pulses, the element 7, the switch 8, the threshold unit 9, the starting unit 10 and the display unit 11. The power of all units of the device is about the power supply unit (not shown). The device can operate in standby mode, working on two detectors and on standby mode on one broadcaster, when exiting the page (or disconnecting another one. In standby mode on two sensors, the device works as follows. The output signal of each sensor 1 and 2 is represented the frequency of the voltage pulses increasing with the amplification of the controlled influence of the flame on the sensing element of the sensor In the absence of a flame in the controlled area from the outputs of sensors 1 and 2 to the corresponding inputs of the element OR 3 and the trigger and 4, background pulses are received at a frequency of € i and, triggering the cyclical operation of trigger 4 with frequency lu.. The voltage pulses from the outputs of trigger 4, alternately entering the inputs of the expanders 5 and 6 pulses, continuously maintain a high voltage level at both inputs of the element I 7. In switch 8, the output signal of the element And 7 cuts off the output of the element OR 3 and thus ensures the input to the input of the threshold block 9 PULSES from the tijHrtepa 4 frequency / g output. Since the frequency of the trigger 4 with a separate start is equal to the smallest of the two frequencies triggered by pulses, the threshold of the stripping of the threshold block 9 only one of them does not trigger the device, its operation occurs only when the flame is simultaneously detected by two sensors 1 and 2, when The smallest of the two frequencies entering the trigger input 4 will exceed the specified threshold. In this case, from the output of the prrogovy block 9 to the input of the starting block 1O, a signal is sent to trigger the latter. Thus, in the standby mode, the proposed device, by using sensor 1 and 2, does not respond to possible false increases in the frequency of background pulses on one sensor 1 or 2. It only occurs when a flame is detected by two sensors 1 and 2 simultaneously, since the connection of the sensor outputs 1 and 2 to the input of the threshold unit 9 through the trigger 4 provides control on the sensor 1 or 2 with the lowest frequency of the output pulses, then the information supplied to the input of the threshold unit 9 does not need to be checked on another sensor. This makes it possible to reduce the intrinsic launch time of the signal-starting device approximately by a factor of two. Transition of the device to standby mode on one sensor 1 or 2 occurs in cases when from one of sensors 1 and 2 the output of pulses to the corresponding trigger input 4 stops. Regardless of the reasons for the disappearance of the indicated pulses (sensor 1 or 2 failure, damage to the connecting cable of sensor 1 or 2, disconnection of one sensor, etc.) trigger 4 stops its cyclic operation. By stopping trigger 4, a high voltage level is established at one input and a low voltage level at another. The presence of expanders 5 and 6 pulses ensures that the voltage levels at both inputs of the element AND 7 remain high after the stop of trigger 4 stops. After the specified time has passed, the voltage levels of 4ia BXOQUJC 1 & I and 7 will be equal to: voltage at the outputs of the trigger 4, causing the output of the element 7 and s.otvetstvukitsem input of switch 8, the disappearance of the signal blocking the passage to the input of the threshold block 9 pulses from the output of the element OR 3, the process of switching the device to standby they have one sensor end. In the specified mode, the voltage pulses from the output of an operable sensor 1 or 2 through the element OR 3 and the switch 8 arrive at the input of the threshold unit 9. The device operates with an increase in the frequency of the pulses at the output of the serviceable sensor 1 or 2 above the threshold of triggering the threshold unit 9. Since the operation mode of the device is unambiguously related to the operation mode of the trigger 4, the presence of the display unit 11 at the output of the trigger 4 allows monitoring the operation mode of the device. After eliminating the malfunction or replacing sensor 1 or 2, the very first switching of trigger 4 restores the balance of the voltages at the inputs of the AND 7 element, again blocking the output of the OR 3 element and ensuring that the input of the threshold unit 9 receives pulses from the output of the trigger 4. Thus, the device provides

automatic return to standby mode with two sensors,.

The delay time is a definite period and the sensitivity of the device when switching to standby mode with a single sensor, it is desirable to have a minimum, however, to obtain a constant voltage level at the outputs of p1 expander 5 and 6 in the cyclic mode of trigger 4, it is necessary that less than the maximum possible period following background pulses. In the case of using the device in combination with light firemen and hangers on the basis of gas-discharge photoelectric sensitive elements, the indicated time is 1-2 s, which has practically no effect on reliability. functioning of automatic fire extinguishing installations.

The fire alarm trigger allows approximately two times reduction in the device’s own response time, and also makes it possible to replace the malfunctioning fire detector, its connecting cable, or sensitive sensor that has depleted the life of the fire alarm trigger device. the time automatically switches to the standby mode according to the operable | detector and then recovers

normal mode on two weighing machines.

Claims (1)

1. US Patent No. 3544792, cl. 25O-833, published. 1970. 2, USSR author's certificate No. 633047, cl. G08 17/12 1973 (prototype).