SU1001132A1 - Fire alarm - Google Patents

Description

The invention relates to a technique for controlling the combustion of a torch torch and can be used at power plants where fuel is burned (power engineering, metallurgists, etc.).

A combustion detector is known, which contains an ionization electrode, a filter, an actuating element, and an isolation control unit t1.

In this signalization ionization electrode, an increased working voltage is applied, which requires an improved quality of electrical isolation from the ionization electrode.

A fire detector is known that contains an ionization electrode connected to the filter inlet, the output of which is connected to an amplifier, the output of which is connected to the input of the izoshiya control unit and to the input of the actuator, an alternating voltage source, the output of which is connected to the burner body, the checker, the output of which connected to the input of the filter C2.

The disadvantage of the device is that when the insulation quality deteriorates, the output of the filter appears

a signal that, when added to the useful signal of the presence of a torch, reduces the latter, which reduces the reliability of the detector. In addition, the appearance at the input of the filter of the opposite polarity is perceived by the detector as deterioration of the insulation, which also leads to a decrease in the reliability

10 work signaling device.

The purpose of the invention is to detect the reliability of the detector.

The supplied circuit is achieved by the fact that a flame detector, containing an ionization electrode, is connected to the filter input, the output of which is connected to the input of the first amplifier, an alternating voltage source, the first output of which is connected to the burner body, an actuator, an insulation control unit, the second amplifier, the delay unit, the OR element, the filter output is connected to the input of the second amplifier,

25 outputs of the first and second amplifiers are connected to the first to the second 5th input. the element OR, whose output through the delay unit is connected to the input of the actuator

Claims (2)

30 I and the second outputs of the alternating voltage source are connected to the first and second inputs of the isolation control unit, the output of which is connected to the filter input, the isolation control unit is made on two voltage dividers connected between the inputs of the unit, the first voltage divider is made on the first and second resistors, common - the connection point of which is connected to the first input of the reference element, the second divider is connected in series to the third resistor, the first capacitor and the fourth resistor, the common connection point and a third resistor and a first capacitor connected to the second input of the comparison element, and the total point of connection of the fourth resistor and lane Vågå capacitor through a second capacitor connected to the output unit. The drawing shows a block diagram of the detector. The flame detector contains iodization electrode 1, filter 2, amplifiers 3 and 4, element OR 5, delay unit 6, actuator 7, burner 8, alternating voltage source 9, insulation control unit 10, which is made on divider 11 from resistors 12,13, to capacitor 14 on divider 15 from resistors 16,17, comparison element 18, to capacitor 19. The flame detector works as follows. The alternating voltage source removed from the capacitor 14 and the resistor 13 through the capacitor 19, is supplied to the ionization electrode 1 and to the input of the filter 2. The presence of a torch with detecting properties leads to the appearance of a constant component of the capacitor 19 and accordingly filter output 2. The polarity of this voltage is determined by the detecting properties of the kel. The voltage from the output of the filter 2 enters the input of amplifiers 3 and 4 and the output of one of them (depending on the polarity of the voltage from the output of filter 2) appears a signal arriving at the input of the element OR 5. From the output of the element OR through the block b delays are sent to the actuating element 7. The activation of the element 7 indicates the presence of a flame. The delay unit 6 serves to delay the specified shutdown time of the executive element 7 when the signal at the output of the filter 2 disappears. A change in the polarity of the signal at the output of the filter 2 does not lead to the disconnection of the actuator 7 if this change occurs during the time determined by the delay block 6 . The absence of a torch, and as a result, the disappearance of its detecting properties, leads to the disappearance of the voltage at the input of the filter 2 and to the disconnection of the actuating element 7 after a specified time, determined by the block b delay. With the normal resistance of the ionization electrode 1, the voltage taken from the resistor 13 of the divider 11 is greater than the voltage taken from the resistor 17 of the divider 15. These voltages flow into the comparison element 18 and are compared there between themselves. When the insulation resistance deteriorates, the voltage on the resist, -tray 13 decreases due to the fact that parallel to the circuit of the capacitor 14, the resistor 13 is connected to a circuit consisting of the capacitor 19 and the insulation resistance, which leads to an increase in the voltage drop across the resistor 12. the voltage drop across resistors 16 and 17 remains unchanged. When the insulation resistance of the ionization electrode reaches such a value that the voltage difference across the resistors 13 and 17 reaches the response threshold of the comparison element 18, it produces a signal indicating to the operator that the insulation of the ionization electrode is degraded. Thus, the reliability of the detector is improved by the fact that the presence of the plume is controlled regardless of the burning conditions and the isolation control unit does not affect the useful signal coming from the filter. These technical features determine the economic effect of using the invention. Claims 1. A flame detector containing an ionization electrode, connectors; A filter is connected to the first amplifier; an alternating voltage source, the first output of which is connected to the burner body; an actuating element; an insulation monitoring unit; that, in order to ensure the reliability of the detector, a second amplifier was inserted into it, a delay unit, an OR element, the filter output is connected to the input of the second amplifier, the outputs of the first and second amplifiers are connected to the first and second inputs AM of the OR element, the output of which is connected to the input of the actuating element through a delay unit, the first and second outputs of the alternating voltage source are connected to the first and second inputs of the block control isolation, the output of which is connected to the input of the filter. 2. The detector according to claim 1, characterized in that the isolation control unit contains two voltage dividers connected between the inputs of the unit, the first divider is made on the first and second resistors, the connection point of which is connected to the first input of the reference element, the second divider is made on the third resistor, the first capacitor and the fourth resistor, respectively, the common connection point of the third resistor and the first the capacitor is connected to the secondary input of the reference element, and the common connection point of the fourth resistor and the first capacitor is connected to the output of the unit through the second capacitor. Sources of information 1ation taken into account during the examination 1. Khesin M.Ya., Kvasha N.V., Zhirnov F. G. Automatic control of burners of powerful boilers. M.,  Energy, 1972, p. 18.19, fig. ba 2.Avtorskoe certificate of the USSR; № 503267, cl. G 08 B 17/12, 1974 (prototypeJ.