JPH0226135B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a combustion control circuit for a combustor used in a hot air heater or the like.

Conventionally, in this type of combustion control circuit, if the ignition detection circuit becomes abnormal, it may be assumed that ignition has been detected even though the combustion blower is stopped (unburned), and if it is, the ignition transformer will operate. Because fuel was supplied before the ignition transformer was activated, a violent explosion could occur within the combustion chamber, which was dangerous.

The present invention has been made in view of the above-mentioned points, and is intended to eliminate the above-mentioned disadvantages by having a configuration in which the power is cut off if the ignition detection circuit becomes abnormal.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 15. In the figure, 1 is a power plug connected to a commercial power supply, 2 is a relay circuit that controls the operation of the combustion blower and ignition transformer of the combustor, and 3 is a DC power supply that receives power from relay circuit 2 and operates the circuit. 4 is a heater thermo circuit that controls the temperature of the vaporization heater for vaporizing liquid fuel; 5 is a heater thermocircuit that controls the activation/stop of combustion and the amount of fuel to maintain and control the room temperature to increase the amount of combustion;・Temperature control circuit 6 controls the temperature, 6 is a heat-up memory circuit that remembers that the temperature of the vaporization heater has risen to the temperature that vaporizes the fuel, 7 is a temperature control circuit 5 that controls combustion for a certain period of time when combustion is stopped. 8 is a sequence circuit that performs a combustion sequence; 9 is a vibration detection circuit for an earthquake-resistant automatic fire extinguishing system that detects shaking that exceeds a predetermined level such as an earthquake and stops combustion; 10 is a combustion circuit; 11 is an oscillation circuit that controls the supply amount of liquid fuel; 12 is a pump drive circuit for driving a pump that feeds liquid fuel; 1
3 is a current fuse, 14 is a convection blower, 15 is an auto-cut that detects abnormal heating of the combustor and cuts off the power supply, and 16 is a relay that switches according to the excitation state of a relay coil 83, which will be described later, to change the output of the blower. Contacts 17 and 18 are both power switches, and while power switch 17 maintains its state when turned on, power switch 18 closes only the moment it is turned on. A relay contact 19 is connected in parallel to the power switch 18, and is turned on and off in accordance with the excitation of a relay coil 146, which will be described later. 20 is a capacitor for noise absorption, 21 is a surge absorber, 2
2 is a terminal for connecting the power supply circuit 3 and the relay circuit 2; 23 is a timer motor for automatic operation;
24 is a heater for vaporizing liquid fuel; 25 is a relay contact that is connected in series to the heater 24 to control energization of the heater 24; and a relay coil 57, which will be described later.
It takes on/off state depending on the excitation state of. 26 is a relay contact that turns on and off depending on the excitation state of a relay coil 115 (described later), 27 is a blower for supplying combustion air, and 28 is a relay coil 8 (described later).
4, a relay contact that switches the output of the blower 27 according to the excitation state; 29 and 30, a resistor and a capacitor for surge absorption; 31, a surge absorber; 32, an ignition transformer; and 33, excitation of a relay coil 135, which will be described later. 34 is a terminal that connects the relay circuit 2 and the pump drive circuit 12, 35 is a power transformer, and 36 is a flame rod (not shown) that detects flame current. Terminals to be connected, 37 a rectifier circuit consisting of a diode bridge, 38 a smoothing capacitor, 39 a resistor, 4
0 is a transistor, 41 is a constant voltage diode, 4
2 is a capacitor, resistor 39, transistor 40
A stabilized power source is supplied together with the constant voltage diode 41. 43 is a relay power supply terminal for exciting each relay coil, 44 is a stabilizing power supply terminal for other circuits,
45 is a ground terminal, 46 is a resistor, and 47 is a high temperature thermistor 48 that is attached to the vaporization heater 24 and detects the temperature of the vaporization heater 24.
49 and 50 are voltage dividing resistors; 51 is a capacitor connected in parallel to the resistor 50; 52 is a capacitor connected in parallel to the resistor 46 and thermistor 47; A comparator that inputs the voltage Vb between the
53 and 54 are resistors and diodes interposed between the output of the comparator 52 and the non-inverting input terminal;
Diodes 55 and 56 have their anodes connected between the resistor 46 and the thermistor 47, and 57 is a relay coil that controls on/off the relay contact 25, which is excited in accordance with the output of the comparator 52. 58 is a diode for canceling the back electromotive force; 59 is an energy-saving switch that selects whether or not to energize the vaporizing heater 24 when combustion is stopped by the temperature control circuit 5 connected in series with the diode 56, that is, when the comparator 88 outputs L; 60 is a terminal for connecting the heat-up memory circuit 6 and the heater thermocircuit 4;
1 and 62 are terminals connecting the heater thermocircuit 4 and the temperature control circuit 5, 63 is a resistor, 64 is a diode whose cathode is connected to the terminal 61, and 65 is formed by incorporating several transistors into the same IC. 66 is a timer contact that is controlled on and off by the timer motor 23; 67, 68, and 69 are voltage dividing resistors connected in series between the power supply terminal 44 and the ground terminal 45; and 70 is an inverter made of a transistor array IC. A variable resistor connected in parallel to the resistor 69, 71 a capacitor, 72, 74, 75,
76 is a resistor connected in series between the power supply terminal 44 and the ground terminal 45; 73 is a resistor whose one end is connected between resistors 72 and 74 connected to the anode of the diode 64; and 77 is a resistor 76. 78 is a resistor, 79 is a capacitor, 81 is inputted with the positive potential of the capacitor 71 on the inverted side, and the positive potential of the capacitor 79 on the non-inverted side. a comparator; 80 is a resistor that connects the output terminal of the comparator 81 and the non-inverting input terminal; 82 is a resistor that connects the output terminal of the comparator 81 and the power supply terminal;
83 is a relay coil that switches and controls the relay contact 16, 84 is a relay coil that switches and controls the relay contact 28, 85 is an inverter interposed between the output terminal of the comparator 81 and the relay coils 83 and 84, and 86 is an inverter. A diode whose cathode is connected to the output terminal of 85, a capacitor 87 interposed between the resistor 73 and the ground terminal 45,
88 is a comparator to which the positive potential of the capacitor 87 is input to the non-inverting side, and the positive potential of the capacitor 71 is input to the inverting side; 89 is the comparator 8;
8 a resistor connecting the output terminal and the non-inverting side input terminal; 90 a resistor connecting the power supply terminal 44 and the output terminal of the comparator 88; 91 a terminal connecting the temperature control circuit 5 and the oscillation circuit 11; 92 is temperature control circuit 5
and a terminal for connecting the heat-up memory circuit 6;
93 is a diode whose cathode is connected to the terminal 60, 94 is a resistor connected to the anode of the diode 93, 95 is a diode whose cathode is connected to the terminal 92, 96 is a resistor connected to the anode of the diode 95, and 97 is a resistor connected to the anode of the diode 95. A capacitor is interposed between the resistor 96 and the ground terminal 45, 98 is a resistor connecting the power supply terminal 44 and the resistor 94, 99 is a resistor, and 100 is a connecting point between the resistor 99 and the resistor 98 and the resistor 96. 101 is a PUT whose anode is connected to the connection point of resistors 96 and 98 and the gate is connected to resistor 99, 102 is PUT10
a diode 103 whose anode is connected to the cathode of 1 and whose cathode is connected to the ground terminal 45;
is the inverter connected to the gate of PUT101,
104 is a terminal for connecting the heat-up memory circuit 6 and the sequence circuit 8; 105 is a power supply terminal 44;
and the terminal 104, 106 is the terminal 1
Diode with anode connected to 04, 107
is a resistor connected in parallel with the diode 106, 1
08 is a capacitor interposed between the resistor 107 and the ground terminal 45, and 109 is a diode 106.
The diode is interposed between the cathode of
06 and the capacitor 108 constitute a CR timer circuit. 110 and 111 are voltage dividing resistors, 1
13 is a capacitor connected in parallel to the resistor 110; 114 is a comparator to which the positive side potential of the capacitor 108 is inputted to the inverted side; the positive side of the capacitor 113 is inputted to the non-inverted side; 112 is the output terminal of the comparator 114 and the non-inverted side; A resistor 115 connected to the side input terminal is a relay coil that controls on/off of the relay contact 26, and is interposed between the relay power supply terminal 43 and the output terminal of the comparator 114. 116 is a diode for canceling the back electromotive force of the relay coil 115; 117 is a terminal connecting the post-purge circuit 7 with the vibration detection circuit 9 and the ignition detection circuit 10; 119 is a resistor connected to the terminal 104;
120 and 121 are the power terminal 44 and the ground terminal 4
122 is a capacitor, 123 is a resistor 1, and 122 is a capacitor.
21 is a capacitor connected in parallel, 124 is a resistor connected to the positive electrode side of the capacitor 123, 12
5 is a diode interposed between the capacitor 122 and the resistor 119, 126 is a resistor connected to the anode of the diode 125, 127 is the capacitor 1 with the positive potential of the capacitor 122 set to the non-inverting side;
129 is a resistor that connects the output terminal of the comparator 127 and the power supply terminal 44, 129 is an inverter that receives the output of the comparator 127, and 130 is a resistor 124 and an inverter. 131 is a diode whose cathode is connected to the output terminal of the inverter 129; 132 is a connection point between the power supply terminal 44 and the anode of the resistor 126 and the diode 131; 133 is a diode that connects the resistor 119 and the power supply terminal 44; 134 is a diode whose cathode is connected to the anode of the diode 133; 135 is a relay coil that controls on/off the relay contact 33; It is connected between the output terminal of the inverter 129 and the output terminal of the inverter 129. 133' is a diode whose anode is connected to the resistor 132, and the resistors 119, 120, 12
1,124,126,128,132, capacitor 122,123, diode 125,130,
131, comparator 127 and inverter 12
When the ignition signal is not received from the ignition detection circuit 10 during the operation of the timer circuit described later, which is an important part of the present invention, the relay contact 19 is turned off, and the ignition signal is turned off from the ignition detection circuit 10 after the timer circuit has finished operating. It constitutes a low frequency oscillator that causes the ignition transformer 32 to ignite when no signal is received. 134' is a terminal connected to the cathode of diode 133';
The sequence circuit 8 and the ignition detection circuit 10 are connected. 135' is a capacitor connected between the diode 134 and the ground terminal 45;
37 is a resistor that connects the positive side of the capacitor 135' and the output terminal of the comparator 127, and 138 is a transistor whose base and emitter are connected to the resistor 137, together with resistors 136, 137, capacitor 135', and diodes 133, 134. A timer circuit that operates in conjunction with the ignition operation of the ignition transformer 32 is configured. 139 is the transistor 13
140 is a transistor whose emitter is connected to the anode of diode 139; 141 is a resistor that connects the emitter and base of transistor 146; and 142 is a resistor connected to the base of transistor 140. , 143 is a terminal connecting the sequence circuit 8 and the ignition detection circuit 10, 144 is a resistor interposed between the collector of the transistor 140 and the power supply terminal 44, 145 is an inverter that inputs the collector potential of the transistor 140, 146 is a relay coil interposed between the relay power terminal 43 and the output terminal of the inverter 145, and the relay contact 1
9 is turned on and off. 147 is a terminal that connects the sequence circuit 8 and the vibration detection circuit 9, and 148 is an inverter whose output terminal is connected to the terminal 147. When the ignition detection circuit 10 becomes abnormal when the combustion blower 27 is stopped and it is assumed that ignition has been detected. Relay contact 1
9 is off. 149 is a diode whose cathode is connected to the input terminal of the inverter 148;
0 is a resistor connected to the relay power supply terminal 43, 15
1 is a diode whose anode is connected to a resistor 150 and whose cathode is connected to the input terminal of the inverter 148; 152 is a capacitor interposed between the cathode of the diode 151 and the ground terminal 45; and 153 is a diode 151 and the capacitor 15.
A seismic sensor connected in parallel with 2, 150-200gal
It turns off when vibration acceleration is detected. 155 is a resistor that connects the terminal 117 and the anode of the diode 149; 154 is a terminal that connects the vibration detection circuit 9 and the ignition detection circuit 10; 156 is a resistor 15;
7, 158, 159 to the main body ground connected to the ground terminal 45, a voltage drop occurs when a flame current flows. 160 is a capacitor connected in parallel to resistors 158 and 159, 161 is a resistor 15
A capacitor 9 is connected in parallel, 162 is a resistor connected to the positive side of the capacitor 161, and 16 is a resistor connected to the positive side of the capacitor 161.
3, 167 is a voltage dividing resistor, 164 is a capacitor interposed between the resistor 162 and the ground terminal 45, 165 is a constant voltage diode connected in parallel to the capacitor 164, and 166 is connected in parallel to the resistor 163. Capacitor, 169 is capacitor 1
64 to the inverted side, the capacitor 166
168 is a resistor connecting the output terminal of the comparator 169 and the non-inverting side input terminal, 170 is a resistor connected to the power supply terminal 44, and 171 is a resistor that connects the output terminal of the comparator 169 to the non-inverting side input terminal. A diode 172 is interposed between the output terminal and the terminal 134', and 172 is the comparator 1.
173 is an inverter whose input terminal is connected to the anode of diode 172; 174 is a terminal connecting oscillation circuit 11 and sequence circuit 8; 175 is a pulse Transformer, 176 is a semi-fixed resistor, 177 is a resistor, 178 is an anode connected to the resistor 17
7 is a PUT whose cathode is connected to the pulse transformer 195, 199 is a diode inserted between the pulse transformer 175 and the terminal 174 so that its cathode is connected to the terminal 174, and 180 is the pulse transformer 175 and the terminal 134'. 181 is a capacitor connected in parallel to the pulse transformer 175, and 182 is interposed between the gate of PUT 178 and the anode of the diode 180. 183 is a capacitor interposed between the anode of PUT 178 and the anode of diode 180, 184 is a capacitor connected in parallel to resistor 182, 185 is a resistor connected in parallel to capacitor 184 together with diode 186, 187 and 188 are resistors and semi-fixed resistors interposed between the anode of the diode 186 and the terminal 91; 189 are resistors interposed between the anode of the diode 186 and the terminal 104; 190 and 191
192 is a noise absorbing capacitor interposed between the terminals 190 and 191; 193 is a resistor connected to the terminal 190; 194 is a resistor;
5 is a transistor to which a potential difference of resistor 194 is applied between the base and emitter; 196 and 197 are resistors and capacitors connecting the collector and emitter of transistor 195; 198 is a semi-fixed resistor;
9 is a resistor inserted between the semi-fixed resistor 198 and the resistor 196, and 200 is an anode and a cathode connected in parallel to the resistor 196 and the capacitor 197.
PUT, 201 is a capacitor connecting the gate and cathode of PUT 200, 202 is a constant voltage diode, 203 and 204 are constant voltage diodes 202
diode connected in series with 205, 20
6,207 are voltage dividing resistors, resistors 206,207
are the constant voltage diode 202 and the diode 203,
204 , and the potential difference of a resistor 207 is further connected to the gate of PUT 200 . 2
08 is a diode whose cathode is connected to the gate of PUT 200, 209 is a resistor, 210 is a capacitor, 211 is a resistor connected in parallel to the capacitor 210, and 212 is a diode inserted between the resistor 209 and the resistor 211. , its anode is connected to the anode of the diode 208, and together with the resistor 211 and capacitor 210, prevents a pump 219, which will be described later, from malfunctioning. 213 is a capacitor connected in parallel to resistors 209 and 211 and diode 212; 214 and 215 are diodes and a resistor; 216 is a transistor whose base and emitter are connected to resistor 215; 217 is a resistor;
19 is a pump connected to the collector of the transistor 216, 218 is a diode for absorbing the surge generated by the pump 219, 220 is a capacitor connected in parallel to the pump 219 and the transistor 216, 221 is a resistor, and 222 is a terminal 3.
This is a rectifier circuit consisting of a diode bridge that rectifies alternating current from 4.

Next, the effect will be explained.

When the power switches 17 and 18 are turned on, the DC current is rectified to a predetermined level through the power transformer 35 and the rectifier circuit 37 of the power circuit 3 through the terminal 22, and then through the capacitor 38, constant diode 41, transistor 40, etc. Stabilized power is supplied to power supply terminal 44 and relay power supply terminal 43, and timer motor 23 is activated. Each power terminal 4
When power is supplied to 3 and 44, no flame current flows to the main body ground 156, so the comparator 16
The output of the comparator 127 becomes H and the transistor 140 is turned on via the terminal 143, but the capacitor 122 of the sequence circuit 8 is not charged at the start of operation. Even when charging is started, the capacitor 122 does not discharge while the comparator 127 is at an H output, so the transistor 138 is off, and the input potential of the inverter 145 becomes H, and the output of the inverter 145 becomes L. Therefore, in conjunction with the ON operation of the power switches 17 and 18, the relay coil 146 is excited and the relay contact 19 is turned ON. Also, relay power terminal 4
3 and the power terminal 44, in the heater thermocircuit 4, the timer contact 66 is turned on due to the operation of the timer motor 23, and since the temperature detected by the high temperature thermistor 47 is low, even if the energy saving switch 59 is turned off. If the potential Va is the resistance 49,
50, the output of the comparator 52 becomes a low level (L), the relay coil 57 is excited, the relay contact 25 is turned on, and the vaporization heater 24 is activated to generate heat. Due to this heat generation operation, the temperature of the high temperature thermistor 47 rises, and when it reaches the vaporization temperature at time a, the output of the comparator 52 becomes H. At this time, since the timer contact 66 is in the on state, the non-inverting side of the comparator 88 becomes higher than the inverting side and the output of the comparator 88 becomes H, so the PUT 101 turns on and the output of the inverter 103 becomes H. Therefore, since the inverting side of the comparator 114 is higher than the non-inverting side, the output of the comparator 114 becomes L and the relay coil 11
5 is energized and the combustion blower 27 begins to operate with strong output via the relay contact 26. Also, almost at the same time when the inverter 103 becomes the H output, the capacitor 1
22 begins to be charged via the resistors 126 and 132, and when the charging potential of the capacitor 122 becomes equal to or higher than the reference potential set by the resistors 120 and 121 at time b, the output of the comparator 127 becomes H and the output of the inverter 129 becomes L. with resistance 13
6,137 to charge the capacitor 135'. As a result, the relay coil 135 is energized, the relay contact 33 is turned on, and the ignition transformer 32 begins to operate. Also, almost at the same time, the H output of inverter 103 is transmitted to PUT17 via terminal 104.
The anode current of 8 is set below the flame current to the oscillation circuit 11 which satisfies the conditions for oscillation, but the L output of the inverter 129 causes the terminal 174 to
Since the output of the inverter 86 is L, the gate potential of the PUT 178 becomes relatively low due to the resistor 187 and the semi-fixed resistor 188, and the oscillation frequency of the oscillation circuit 11 becomes relatively high. As a result, this relatively high frequency signal is input to the base of the transistor 195 via the pulse transformer 175, and the transistor 195 repeats on/off operations at this frequency. When the transistor 195 is on, the anode potential of the PUT 200 drops, so the PUT 200 is turned off and the current flowing to the gate of the PUT 200 flows into the base of the transistor 216 via the diode 214, turning on the transistor 216 and energizing the pump 219. Fuel begins to be supplied to the combustion section. And PUT
After 200 is turned off, the semi-fixed resistor 1 is turned on again.
98, capacitor 1 via resistors 196 and 199
99 and after a certain period of time, the PUT 200 is turned on, the transistor 216 is turned off, and the power supply to the pump 219 is cut off. When the base signal is again input to the transistor 195 via the pulse transformer 175 in this cut-off state, the transistor 195 is turned on and the PUT 200 is turned off, so the transistor 216 is turned on and the pump 219 is energized again. Therefore, pump 2
19 is turned on and off at the relatively high frequency of the oscillation circuit 11, and a relatively large amount of fuel is supplied from the pump 219 to the combustion section. Then, at the same time as the ignition transformer 32 operates, the capacitor 1
22 is discharged via the resistor 126, the non-inverting side input potential of the comparator 127 becomes L, and the output of the comparator 127 becomes L. Therefore, the output of the inverter 129 becomes H and the relay coil 13
5 is demagnetized, the relay contact 33 is turned off, and the ignition transformer 32 is stopped at time c. On the other hand, the vaporization heater 24, which was once again generating heat via the high-temperature thermistor 47 and the comparator 52, is switched to the comparator 52 at time c by the L output of the inverter 65.
The input potential on the inverted side becomes L, and the comparator 52
Since the output becomes H and the relay coil 57 is demagnetized, the relay contact 25 is turned off and stopped. If the fire has been ignited by the operation of the ignition transformer 32 by this time, flame current will flow from the flame rod 36 to the main body ground 156, the alternating current component of which will be bypassed to the capacitor 160, and only the direct current component will flow through the resistor 1.
58, 159 flows to capacitor 161 and resistor 1
Comparator 1 with a time constant of 57,158
69 becomes an L output after a predetermined time delay and terminals 134',
143 becomes L, while terminal 154 becomes H. Therefore, even if the capacitor 122 is discharged by the L output of the inverter 103 and the output of the comparator 127 becomes L, the capacitor 135' is discharged and the transistor 138 is turned on. The output of the comparator 169 becomes L and the terminal 14
3 becomes L, the transistor 140 is turned off, the input potential of the inverter 145 becomes H, the output of the inverter 145 is maintained at L, and relay contact 1
9 is held in the on state.

Due to this ignition, the fuel continues to be supplied and the room is heated, and when the temperature detected by the thermistor 77 reaches d, the resistance is 6.
7, 68, 69 and the variable resistor 70, the output of the comparator 81 becomes L and the output of the inverter 85 becomes H.
As a result, the relay coils 83 and 84 are demagnetized, the relay contacts 16 and 28 are switched, and the convection blower 14
In addition, the combustion blower 27 is operated at low speed. Further, the output of the inverter 85 becomes H and the potential of the terminal 91 rises, so the potential determined by the resistors 189 and 185 is applied to the gate of the PUT 178, and the oscillation circuit 1
1 oscillates at a relatively low oscillation frequency determined by a resistor 177, a semi-fixed resistor 176, and a capacitor 183. Therefore, the energization frequency of pump 219 is reduced, and the amount of fuel transported by pump 219 is reduced. For example, when the timer contact 66 is turned off by the timer motor 23 at time e, the output of the inverter 65 becomes L.
Therefore, the comparators 81 and 88 are forcibly maintained at the L output, and the temperature control circuit 5 is turned off. As a result of this turning off, the pump 219 stops, combustion stops, and the output of the comparator 169 becomes H. This H output brings the terminals 134' and 143 to H potential, turning on the transistor 140, but since the capacitor 135' has finished discharging, the transistor 138 is off, and the output of the inverter 145 is in the L state, so the relay The coil 146 continues to be excited, but at this time both terminals 174 and 134' are at H level, so the PUT 178 turns off, the pump 219 stops, and the resistor 1 of the capacitor 108
Comparator 1 is delayed due to discharge through 07.
14 becomes H, the relay coil 115 is demagnetized, the relay contact 26 is turned off, and the combustion blower 2 is turned off.
7 stops at time f. At this time, capacitor 1
35' has finished discharging when the comparator 127 outputs L, the transistor 138 is off, the output of the inverter 145 becomes L, and the relay coil 146 is maintained in an excited state.
Further, since the terminal 134' becomes in the H state, the capacitor 122 that has finished discharging begins to be charged via the resistor 126. On the other hand, even after the combustion blower 27 is stopped, the vaporization heater 24 is connected to the high temperature thermistor 47.
Since the heat generation operation is repeated according to the detected temperature, when the vaporization heater 24 reaches the set temperature after the combustion blower 27 stops, the comparator 52 becomes an H output and the comparator 88 also becomes an H output. Therefore,
Since PUT 101 is turned on and the output of inverter 103 becomes H, comparator 114 outputs L, relay coil 115 is excited and relay contact 26 is turned on. As a result, the combustion blower 27 is operated weakly again at time g. Then, as the charging of the capacitor 122 progresses and at time h, the non-inverting input potential of the comparator 127 becomes equal to or higher than the inverting input potential, the comparator 127 outputs H and the inverter 129 outputs L. This excites the relay coil 135, turns on the relay contact 33, and activates the ignition transformer 32. If the ignition detection circuit 10 detects ignition, the terminal 13
4' becomes L, the capacitor 123 discharges, and as a result of this discharge, the inverting side input potential of the comparator 127 becomes equal to or higher than the non-inverting side input potential at time i, the comparator 127 becomes an L output, the output of the inverter 129 becomes H, and the relay coil 135 becomes It is demagnetized, the relay contact 33 is turned off, and the ignition transformer 32 is stopped. If the fire misfires again at point j, the ignition transformer 32 will operate again at point k in the same manner as described above, and if the ignition is not ignited at this time, no flame current will flow to the main body ground 156, so the output of the comparator 169 will become H, and the terminals 134' and 143 will be On the other hand, the output of the inverter 173 becomes L. This causes capacitor 122 to be charged again, but during this charging period transistor 140 is turned on and capacitor 1
Since the transistor 138 is also turned on due to the discharge of the transistor 35', the input potential of the inverter 145 becomes L and its output becomes H. Therefore, relay coil 1
46 is demagnetized, the relay contact 19 is turned off, and all the elements other than the convection blower 14 are stopped at time l.

Further, if the energy saving switch 59 is turned on, the vaporizing heater 24 will not be energized when combustion is stopped, and an energy saving effect will be exhibited at this time.

Furthermore, to briefly explain the operation of the heat-up memory circuit 6, when the terminal 92 is at H, the terminal 60
If is L, PUT 101 is off and terminal 104 is L, and the combustion sequence does not proceed. On the other hand, when the terminal 60 becomes H, the PUT 101 is turned on and the terminal 104 becomes H, starting the combustion sequence. When PUT101 is turned on, terminal 92 goes low.
It will not turn off until . This will memorize that the vaporization heater 24 has reached the vaporization temperature.

Also, briefly explaining the operation of the vibration detection circuit 9, when the vibration sensor 153 detects vibration and turns off, the capacitor 152 is charged via the resistor 150 and the diode 151, and the output of the inverter 148 becomes L and the relay coil 146 is turned off. Demagnetize and turn off the relay contact 19.

To further explain the operation of the temperature control circuit 5 in more detail, when the timer contact 66 is on, when the energy saving switch 59 is turned off, a potential corresponding to the resistance of the high temperature thermistor 47 is input to the inverting side of the comparator 52. Therefore, the comparator 52 outputs H/L depending on the resistance, and the relay coil 57 is energized and braked.

Thereby, the vaporization heater 24 is controlled to a constant temperature. On the other hand, if the energy saving switch 59 is turned on, the comparator 88 is forcibly maintained at L output when the timer contact 66 is turned off, etc., and the comparator 88 is forcibly maintained at the L output.
2 is held at L, the comparator 52 outputs H, the relay coil 57 is demagnetized, and the vaporization heater 24 is no longer energized when combustion is stopped, resulting in an energy-saving effect.

In addition, when the combustion is stopped, specifically when the combustion blower 27 is stopped, the ignition detection circuit 10
Even if the output of the comparator 169 becomes L due to an abnormality, the output of the inverter 137 is H and the output of the comparator 114 is also H.
The H potential is input to the inverter 148 via the inverter 49, and the output of the inverter 148 becomes L. As a result, the input of the inverter 145 becomes L and the output of the inverter 145 becomes H, so the relay coil 14
6 is demagnetized and the relay contact 19 is opened.

Therefore, if the ignition detection circuit 10 is abnormal, the power supply to each element is cut off, resulting in excellent safety.

As explained above, the present invention is mainly designed to detect failure of the ignition detection circuit, and detects ignition when the combustion blower controlled by the heater thermo circuit, temperature control circuit, and post purge circuit is stopped. By providing a means to turn off the self-maintained relay when the circuit detects ignition, it can be used even if the ignition detection circuit is malfunctioning or when the combustion blower stops when the power is turned on, even if the power switch is turned on. ,
This can be detected and the relay can be turned off,
Furthermore, even in the event of a power outage, the self-holding is released and the relay can be turned off in the same way, thereby providing a combustion control circuit with extremely high safety using a completely new method.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a combustion control circuit which is an embodiment of the present invention, Figs. 2 to 8, and Figs. 10 to 10.
Fig. 13 is a detailed circuit diagram of each of the above blocks, Fig. 9 is an overall configuration diagram of the combustion control circuit same as above, and Fig. 14 is a detailed circuit diagram of each of the above blocks.
The figure shows a voltage characteristic diagram of the capacitor 122 and the capacitor 135, where a is the capacitor 122 and b is the capacitor 135. FIG. 15 shows a timing chart of the combustion control circuit. 5...Temperature control circuit, 9...Vibration detection circuit, 10...
...Ignition detection circuit, 19...Relay contact, 88...
Comparator, 103... Inverter, 114...
... Comparator, 115 ... Relay coil, 14
8...Inverter, 150...Diode, 16
9...Comparator, 173...Inverter.

Claims (1)

[Claims] 1 A relay that is excited by the ON operation of the power switch and continues to supply power to each element, a heater thermo circuit that controls the vaporization heater, a temperature control circuit that detects room temperature, and a post purge that operates the combustion blower for a while after combustion has stopped. In a combustion control circuit that includes a circuit, an ignition detection circuit that monitors whether combustion is being performed normally, and a combustion blower, when the combustion blower controlled by the heater thermocircuit, temperature control circuit, and post purge circuit is stopped, the A combustion control circuit comprising means for turning off the relay when the ignition detection circuit detects ignition.