RU2183797C1 - Device for monitoring and control of gas heat generator - Google Patents

Abstract

FIELD: heat-power engineering; devices for monitoring and control of heat generators provided with injector torch. SUBSTANCE: proposed device ensures lighting-up of torches and protection of heat generator; it includes valves of igniting and working torches, protection sensors connected in series, flame monitoring unit with contact output, power supply source, START button, interlocking unit, first and second diodes, first resistor, two-position switch with first and second switching directions, temperature regulator, electronic switch contains first and second transistors, second, third, fourth, fifth, sixth resistors, capacitor and third diode. EFFECT: enhanced functional reliability and operational safety. 1 dwg

Description

 The invention relates to a power system, in particular to devices for monitoring and regulating heat generators with an injection burner.

 It is known "Pneumatic device for regulating boiler units" (a. From. USSR N 416523, F 23 N 5/00, publ. 02.25.1974, bull. N 7). The device provides ignition of the ignition and working burners, shutting off the gas supply to the burners in case of traction violation, loss of the flame of the ignition burner, regulation of the temperature of the coolant.

 It is known "Device for monitoring and regulating a gas water heater" (a. From. USSR N 566075, F 23 N 5/06, F 23 H 9/20, publ. 25.07.1977, bull. N 27). The device relates to the automation of domestic gas heating facilities, provides the ability to supply gas to the ignition and working burners, control the presence of the igniter flame, the presence of draft in the chimney, shut off the gas supply to the burners in the event of the ignition flame extinguishing and violation of the draft at the outlet of the heat generator, regulation of the temperature of the heat carrier at a given level.

 Devices belong to pneumatic systems for automation of boiler plants, the advantage of which is ease of maintenance and low cost compared to electrical systems, the possibility of operating a heat generator in the absence of electricity.

The disadvantages of systems with pneumatic automation in comparison with electrical systems are:
1. Limited opportunities to perform the functions of safety automation associated with the need to install a large number of impulse tubes on the heat generator, which, on the one hand, makes the design of the automation system cumbersome, on the other hand, increases the risk of gas leakage into the furnace through the nozzle damper ", which should be equipped with protection sensors.

2. The possibility of using direct-acting valves to control the supply of fuel to the burners is excluded. The desirability of using direct-acting valves is due to the possibility of:
- minimize the size of valves used in the automation system;
- reducing the level of fuel leakage through the shutoff member;
- work at a fuel pressure at the inlet of the heat generator lower than that which occurs in the case of using pneumatic automation.

 3. There is no possibility of indicating the operating and emergency conditions of the heat generator.

 Known set of controls KSU-1 (P.P. Rybakov. Automation of gasified units. L.: Nedra, 1984, S. 191 - 199). The kit relates to electrical automation systems, designed to control a hot water boiler with a capacity of 0.5 to 3.5 MW, provides ignition of the ignition and working burners, on-off control of the power of the boiler, safety automatics, indication of operating and emergency conditions of the boiler. The kit provides the ability to connect a large number of protection sensors. Actuators, including the valves of the working and pilot burners, are switched on using electromagnetic relays.

The disadvantages of the KSU-1 kit are:
1. The complexity of the security automation system.

 2. Low reliability of control circuits of actuators.

 3. The lack of boost mode when the valves are turned on.

 The first drawback is that a special channel is used to process the signal of each protection sensor (a separate circuit). The second - with the use of electromagnetic relays in control circuits, the disadvantages of which are the generation of interference when switching an electric circuit, as well as the limited resource of switching cycles. The third disadvantage leads to increased temperature and, as a consequence, to a decrease in the functional reliability of electromagnetic drives.

 Closest to the claimed is a "Device for ignition and burner protection", a. from. USSR N 1126715, class F 23 N 5/24, publ. 11/30/1984, bull. N 44. The device is intended for use in the automation of boiler units, industrial furnaces, etc. The device contains the valves of the ignition and working burners, a flame control device, series-connected contacts of the protection sensors, a start button. The advantage of the device is its simplicity, the ability to connect a large number of protection sensors without further complicating its circuit.

The disadvantages of the device are:
1. Inadequate safety of use of the device in heat generators operating on natural gas.

 2. Low reliability of the device.

 Insufficient safety is connected with the fact that there is a danger of gas supply to the burners with an unlit igniter, for example, because the contacts of the flame sensor turned out to be (for example, as a result of a malfunction) closed. This, in turn, can cause an emergency.

The low reliability of the device is due to:
- the use in his circuit of electromagnetic relays, the use of which, in contrast to contactless elements, reduces the reliability of the device,
- the lack of forcing valves for the ignition and working burners.

The objectives of the claimed device are:
1. Improving the safety of the heat generator when using the inventive device.

 2. Improving functional reliability.

 Fulfillment of the tasks is achieved by the fact that the proposed device for monitoring and regulating a gas heat generator, providing ignition of the burners, protection of the heat generator and containing valves of the ignition and working burners, series-connected protection sensors, a flame monitoring device with a contact output, a power source, the Start button, characterized in that it includes an additional locking device, first and second diodes, a first resistor, a bi-directional switch of the first and second directions comm Utilization, temperature controller, electronic key, which includes the first and second transistors, second, third, fourth, fifth, sixth resistors, capacitor, third diode.

 The protection sensors and the flame monitoring device are connected in series with the second diode, the first resistor and the pilot burner valve.

 In parallel with the flame control device, the second diode, the first resistor, the Start button, a normally closed contact of the second direction of the bi-directional switch and the first diode are installed in series.

 A normally closed contact of the second direction of the bi-directional switch and the first diode are connected to the first input of the blocking device.

 The output of the locking device is connected to the second input of the temperature controller, the output of the temperature controller to the second input of the electronic key, and the output of the latter to the valve of the working burner.

 A normally open contact of the first direction of a bi-directional switch is connected on one side to the output of the flame control device, a second diode, a second input of the blocking device, and on the other, to the first inputs of the temperature controller and electronic key.

 The first input of the electronic key is connected to the emitter of the first and the collector of the second transistor, through the second resistor to the second input of the electronic key and then through the third resistor to the base of the first transistor.

 Two chains are connected to the collector of the first transistor, consisting of: the first of the fourth and fifth resistors connected in series, the second of the capacitor and the sixth resistor connected in series, the last connected to the base of the second transistor and through the third diode with the fourth and fifth resistors.

Wherein:
1. Improving the safety of the heat generator in the case of using the inventive device in it is achieved through the use of a locking device and a bi-directional switch.

2. Improving functional reliability is achieved by applying:
- Forcing mode when the valves of the pilot and working burners are turned on;
- non-contact valve control of the working burner.

 The use of a blocking device and a bi-directional switch "Ignition-Work" eliminates the possibility of an uncontrolled command to turn on the valve of the working burner to the electronic key in the event of a false operation of the flame control device or in the case of incorrect operator actions during the start-up of the heat generator.

 If the operator acts improperly (the bi-directional switch at the ignition stage is set to "Work") and a false signal appears about the presence of a flame, uncontrolled gas supply to the working burner is not possible, since a blocking instruction for the working valve burners.

 If the operator acts correctly during ignition of the ignition burner (bi-directional switch is set to “Ignition”) and a false signal appears at the output of the flame monitor, uncontrolled gas supply to the working burner is impossible due to the fact that the power supply circuit of the temperature regulator and electronic key are interrupted, burner valve.

Improving safety when using the inventive device also contributes to:
1. Installing an indicator at the output of the flame control device, which allows to detect the fact of a false operation of the flame control device before the ignition of the ignition burner by the indicator on.

 2. The absence of intermediate switching elements in the shutdown circuit of the heat generator in the event of an emergency. In the prototype, to turn off the heat generator in the event of a flame failure or other emergency, an intermediate relay is used, the contacts of which break the power circuit of the valves of the working and pilot burners. The presence of an intermediate relay reduces the reliability of the shutdown of the heat generator in an emergency. In the inventive device in the event of any emergency protection, including in the event of a flame failure, the power supply circuit of the valves of the ignition and working burners is broken by the contacts of either the protection sensors or the flame monitoring device (depending on which emergency protection has triggered an emergency).

Improving the functional reliability of the claimed device compared to the prototype is achieved by:
1. Non-contact valve control of the working burner, since contact circuits implemented using electromagnetic relays have a limited service life, and are often a source of unstable operation of the device.

 2. Application of boost modes for valve control.

 Forcing modes, as you know, are intended for feeding to the actuating element with an electromagnetic drive of various powers in transient and steady state. This makes it possible to increase the reliability of switching on the actuator (due to the fact that at the moment of switching on, a large amount of power can be supplied to the drive without fear of overheating, since the transient process is very small in time), to reduce the heating of the actuator actuator in steady state, i.e. to. the power required to keep the actuator in working condition is required several times less than when it is turned on.

The boost mode for driving the ignition burner is carried out:
1. At the start-up stage, by supplying the full supply voltage to the drive coil through the normally closed contacts of the protection sensors, the “Start” button, the normally closed contact of the bi-directional switch and the first diode, while almost all the voltage of the power source is applied to the coil of the electromagnetic drive of the pilot burner valve.

 2. At the stage of holding the pilot burner valve in working condition - by limiting the power supplied to the coil of the electromagnet using the first resistor. In this case, the supply voltage to the valve actuator comes through the contacts of the protection sensors, the flame control device, the second diode and the first resistor.

 Forcing mode and non-contact valve control of the working burner is carried out by the electronic key circuit.

Thus, the use of the claimed solution:
- the locking device and the bi-directional switch can improve the safety of the device both in case of improper actions by the operator, and during false alarms of the flame control device during the ignition of the heat generator;
- the “Start” button, bidirectional switch of the first and second diodes, resistor, electronic key allows you to implement non-contact valve control using the boost mode, refuse to use electromagnetic relays in the circuit and, as a result, increase the functional reliability of the device.

 In FIG. 1 is a diagram of a device for monitoring and regulating a gas heat generator; FIG. 2 is a diagram of an electronic key; FIG. 3 is a variant of a circuit of a locking device; FIG. 4 is a variant of a circuit of a temperature controller.

 The device for monitoring and regulating the gas heat generator contains the ignition valve 1, the working 2 burners, the protection sensors 3 connected in series and the flame control device 4 with the contact output, the power supply 5, the Start button 6, the locking device 7, the first 8 and second 9 diodes, the first resistor 10, a bi-directional switch of the first 11 and second 12 directions, a temperature controller 13, an electronic key 14, display elements 15, a power switch of the device 16.

 The device operates as follows.

 In the initial state, with the power turned on and there is no ignition burner flame, the bi-directional switch is in the “Ignition” position, while the first direction 11 of the bi-directional switch is open, and the second direction 12 of the bi-directional switch connects the “Start” button 6 to the first diode 8 and the first input blocking devices 7. In the normal (non-emergency) state of the protection sensors 3, the supply voltage from the source 5 is supplied to the input of the flame control device 4, the Start button 6 and the power supply bus of the blocking device and (not shown in the diagram). A low level signal is generated at the output of the interlock device. The latter bypasses the input of the temperature controller 13, (thereby setting the minimum control temperature), as a result of which the temperature controller 13 sets the valve of the working 2 burner to the off state. When you press the "Start" button 6, the supply voltage through its contact and a normally closed contact of the second direction 12 of the bi-directional switch is supplied to the first input of the locking device 7, the first diode 8 and then to the valve 1 of the ignition burner. Gas through the valve 1 (after turning it on) enters the ignition burner and is ignited (ignition burner, its ignition elements are not shown in Fig. 1). The “Start” button 6 is held pressed until the flame monitoring device 4 is triggered. The moment of operation of the flame monitoring device is controlled by indication element 15 connected to its output.

 When the flame control device 4 is activated, the voltage from its output through the second diode 9 and the first resistor 10 is fed to the coil of the electromagnetic drive of the valve 1 of the pilot burner. The start button 6 can be released. The actuator of the valve 1 of the ignition burner goes from the forced on mode with the "Start" button pressed to the valve holding mode. The power supplied to the valve is limited by the first resistor 10. At the same time, the voltage from the output of the flame control device 4 is supplied to the second input of the blocking device 7. The blocking device removes the ban on switching on valve 2 of the working burner. At the output of the device (for the embodiment of the locking device 7 shown in FIG. 3), a high potential is established.

 The bidirectional "Ignition-Operation" switch can be moved to the "Operation" position. In this case, the first direction 11 of the bi-directional switch connects the output of the flame control device 4 with the first inputs of the temperature controller 13 and the electronic switch 14, thereby providing a supply voltage to them. Depending on the actual temperature of the coolant and its setting, the temperature controller 13 controls the state of the valve 2 of the working burner. In the event of an emergency, when one of the protection sensors 3 or the flame monitoring device 4 is triggered, the power supply circuit of the ignition valves 1 and the working 2 burners opens. The operation of the heat generator is terminated.

 The electronic switch 14, the circuit of which is shown in figure 2, contains a second 17, third 18, fourth 20, fifth 21 and sixth 24 resistors, capacitor 22, third diode 23, first 19 and second 25 transistors. In the initial state, in the absence of a command to turn on the valve 2 of the working burner, the transistor 19 is closed. The transistor 25 directly controls the valve actuator 2 of the working burner. When the control signal arrives at the first input of the electronic key 14, the transistor 19 opens, potentials from two points come to the base of the transistor 25.

 From the divider formed by the fourth 20 and fifth 21 resistors, a constant potential arrives at the base of the second transistor 25, the value of which determines the operation mode of the transistor in steady state. By changing this potential, it is possible to regulate the power supplied to the valve to keep it in working condition.

 An exponential voltage pulse is supplied from the collector of the first transistor 19 through the capacitor 22 and the sixth resistor 24 to the base of the second transistor 25. The amplitude of this pulse is close to the voltage of the power source, and the exponential time constant is determined by the time constant of the RC circuit formed by the capacitor 22 and the sixth resistor 24.

 The exponential pulse is used to pass through the second transistor 25 the maximum current pulse necessary to turn on valve 2 (for setting the forced mode of turning on the valve) of the working burner.

 In the inventive device, it is possible to use various variants of locking schemes 7 and temperature controller 13.

 In an example implementation of the inventive device, the locking device and temperature controller circuits shown in FIGS. 3, 4 were used.

 Functionally, the locking device 7 should allow the passage of the command to turn on the electronic key 14 only when the ignition valve is turned on.

In the considered example of the locking device 7 shown in figure 3, this condition is satisfied in the case of:
- if the output of the flame control device 4 to the valve actuator 1 of the ignition burner receives the voltage to keep it in working condition (the same voltage is supplied to the second input of the locking device),
- if at the same time that the first condition is fulfilled, at least for a short time, a boost voltage is supplied to the actuator of the valve 1 of the ignition burner to turn on valve 1 (this voltage is supplied through the "Start" button and the normally closed second-direction contact 12 of the bi-directional switch). This voltage is supplied to the first input of the blocking device 7.

 When the above conditions are met, the ignition valve 1 of the burner is turned on, the locking device 7 removes the ban on the inclusion of the valve of the working burner.

 The considered circuit of the locking device 7 contains resistors 26, 27, 28, 31, 32, a capacitor 30, a thyristor 29, a comparator 33, a diode 34, a capacitor 35. The principle of operation of the device is based on the use of a thyristor as a memory element. In the initial state, the thyristor 29 is closed, at the input of the comparator 33 receives a high potential. The second input of the comparator 33 receives voltage from the divider, consisting of resistors 31 and 32. In this case, the voltage at the output of the divider is selected so that it is always less than the voltage at the first input of the comparator when the thyristor 29 is closed. This condition corresponds to a zero potential at the output of the comparator 33.

 When the flame monitoring device 4 is triggered, the voltage from its output goes to the second input of the blocking device 7. At the first input of the blocking device 7, when the "Start" button is pressed, the voltage comes from a normally closed contact of the second direction 12 of the bi-directional switch. This voltage after the divider, consisting of resistors 26 and 27, is supplied to the control input of the thyristor 29, which opens and remains in such a state while there is voltage at its anode coming from the flame control device 4.

 An open thyristor shunts the 1st input of the comparator to ground. In this case, the voltage at its second input becomes higher than the potential of the first input. A high potential is established at the output of the comparator. In this case, the effect of the locking device 7 on the temperature controller 13 is terminated (thereby removing the ban on controlling the valve 2 of the working burner). The device maintains a new state for the entire time until voltage is supplied to its second input from the flame control device. In the event of a flame failure, the voltage at the input 2 of the interlock 7 becomes zero, the thyristor 29 closes, the interlock 7 stops the temperature controller 13, and the valve 2 of the working burner turns off.

 The temperature controller, the circuit of which is shown in figure 4, contains resistors 36-42, 45, a comparator 43, a capacitor 44. Resistors 36, 37, 38 form a divider of the temperature regulator. In this case, the resistor 37 is variable. Resistors 39-42 form a divider of the temperature sensor of the coolant. In this case, the resistor 39 is a temperature sensor. The comparator 43 operates in the threshold element mode. If the potential of the temperature setpoint exceeds the potential taken from the divider of the temperature sensor, which corresponds to the state when the coolant temperature is lower than the set value, the potential is established at the output of the comparator 43 at which the electronic key 14 and, accordingly, the valve 2 of the working burner are turned on. And vice versa, if the potential from the coolant temperature setter is lower than the voltage taken from the coolant temperature sensor, the voltage at the output of the comparator 43 becomes close to zero, the electronic switch 14 closes, valve 2 is turned off.

 The inventive device for monitoring and regulating a gas heat generator is made using the following components.

1. Figure 1 contains:
- the valve of the ignition burner 1, using the principle of direct control, the valve 2 of the working burner, which is a membrane type valve, the actuators of the valves of the ignition and working burner are designed for an operating voltage of 9-12 V;
- protection sensors 3, which are used as sensors-switches of gas pressure, water, water temperature, draft in the chimney with the output in the form of a "dry contact";
- "Start" button - a button of the type KMD1-1, a bi-directional switch - a toggle switch MTD-3, a power switch of the device - MTD-1, the first 8 and second 9 diodes - diodes of the type KD522, resistor 10 - a resistor of type C2-33N-2- 180 Ohm, indicators 15 - LEDs type AL 307BM.

2. Figure 2 (electronic key circuit) contains:
- resistors 17, 18 - C2-33H-0.125-3.3 kOhm, transistor 19 - transistor KT361 V (D), resistors 20, 24 - C2-33H-0.125-1 kOhm, resistor 21 - C2-33H-0.125- 430 Ohm, capacitor 22 - K50-35-25V-47 uF, diode 23 - diode KD522, transistor 25 - transistor KT829 (A-D).

3. Figure 3 (blocking device diagram) comprises:
- resistor 26 - C2-33H-0.125-1.2 kOhm, resistors 27, 28, 31 - C2-33H-0.125-1 kOhm, capacitors 30, 35 - K10-17-H90-1 uF, thyristor 29 - KU112A, resistor 32 - C2-33H-0.125-7.5 kOhm, comparator 33 - K1401CA1, diode 34 - KD522.

4. Figure 4 (temperature controller circuit) contains:
- resistor 36 - C2-33H-0.125-18 kOhm, resistor 37 - SP2-2-16 kOhm, resistor 38 - C2-33H-0.125-30 kOhm, resistor 39 - thermistor ST14-16-10 kOhm, resistor 40 - C2 -33N-0.125-10 kOhm, resistor 41 - SP5-2VB-0.5W-3.3 kOhm, resistor 42 - C2-33N-0.125-20 kOhm, comparator 43 - K1401CA1, capacitor 44 - K10-17-N90- 1 uF, resistor 45 - C2-33H-0.125-1 MΩ.

The inventive device:
1. Eliminates the possibility of uncontrolled inclusion of the valve of the working burner.

 2. Increases the functional reliability of the device at least three times in comparison with the prototype.

Claims (1)

 A device for monitoring and regulating a gas heat generator, providing ignition of the burners, protection of the heat generator and containing the valves of the ignition and working burners, series-connected protection sensors, a flame control device with a contact output, a power source, the Start button, characterized in that the device includes locking device, first and second diodes, first resistor, bi-directional switch with first and second directions of switching, temperature controller, electronic key, which includes the first and second transistors, the second, third, fourth, fifth, sixth resistors, a capacitor, a third diode, and the protection sensors and the flame control device are connected in series with the second diode, resistor and pilot burner valve, in parallel with the flame control device, the second diode, the first resistor has a series-connected Start button, a normally closed contact of the second direction of the bi-directional switch and a first diode, a normally closed contact of the second direction of the bi-directional switch the switch and the first diode are connected to the first input of the locking device, the output of the locking device is connected to the second input of the temperature controller, the output of the temperature controller to the second input of the electronic key, and the output of the latter to the valve of the working burner, normally open contact of the first direction of the bi-directional switch on one side connected to the output of the flame control device, the second diode, the second input of the blocking device, on the other hand, to the first inputs of the temperature controller and an electronic key , the first input of the electronic key is connected to the emitter of the first and the collector of the second transistor, through the second resistor to the second input of the electronic key and then through the third resistor to the base of the first transistor, two chains are connected to the collector of the first transistor, consisting of: the first - in series fourth and fifth resistors; the second is from a series-connected capacitor and a sixth resistor, while the latter is connected to the base of the second transistor and through the third diode to the fourth and fifth resistors.

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