JPH028215B2 - - 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, this type of combustion control circuit requires only one ignition operation, so in the event of an ignition error or misfire, it cannot be re-ignited, or even if it can be re-ignited, it is extremely expensive and requires a complicated logic circuit. The number of parts increases, resulting in a decrease in reliability.

The present invention has been made in view of the above points, and focuses on the fact that ignition errors rarely occur in current combustors, and performs re-ignition operation with a relatively simple circuit configuration only in the case of a misfire midway through. This provides an inexpensive and highly reliable combustion control circuit.

Embodiments of the present invention will be described below with reference to FIGS. 1 to 14. 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,
3 is a power supply circuit that receives power from the relay circuit 2 and constitutes a DC power source for circuit operation; 4 is a heater thermocircuit that controls the temperature of a vaporization heater for vaporizing liquid fuel; and 5 is a heater thermocircuit for controlling and maintaining a constant room temperature. a temperature control circuit that controls the combustion amount by controlling the activation/stop of combustion and the amount of fuel; 6 a heat-up memory circuit that stores information that the temperature of the vaporization heater has risen to a temperature that vaporizes the fuel; 7; 8 is a post-purge circuit that delays and stops the combustion blower for a certain period of time when combustion is stopped by the temperature control circuit 5; 8 is a sequence circuit that performs the combustion sequence; and 9 is a combustion circuit that detects shaking that exceeds a predetermined level such as an earthquake. 10 is an ignition detection circuit that detects the combustion state of the combustor, 11 is an oscillation circuit that controls the amount of liquid fuel supplied, and 12 is for driving a pump that feeds liquid fuel. 13 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 switched according to the excitation state of a relay coil 83, which will be described later. Relay contacts 17 and 18 for switching the output of the circuit 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, 22 is a terminal for connecting the power supply circuit 3 and the relay circuit 2, 23
24 is a timer motor for automatic operation; 24 is a heater for vaporizing liquid fuel; 25 is a relay contact connected in series to the heater 24 to control the energization of the heater 24; It takes an on/off state depending on the situation. 26 is a relay contact that turns on and off depending on the excitation state of a relay coil 115, which will be described later; 27 is a blower for supplying combustion air; and 28 is switched according to the excitation state of a relay coil 84, which will be described later, to control the output of the blower 27. Relay contacts for switching, 29 and 30 are resistors and capacitors for surge absorption, 31 is a surge absorber, 3
2 is an ignition transformer; 33 is a relay contact that turns on and off in response to excitation of a relay coil 135 to be described later to control the ignition transformer 32; 34 is a terminal that connects the relay circuit 2 and the pump drive circuit 12; 35;
36 is a terminal connected to a flame rod (not shown) for detecting flame current, 37 is a rectifier circuit consisting of a diode bridge, 38 is a smoothing capacitor, 39 is a resistor, 40 is a transistor, and 41 is a A constant voltage diode 42 is a capacitor, which together with a resistor 39, a transistor 40, and a constant voltage diode 41 supplies a stabilized power source. 4
3 is a relay power terminal for excitation of each relay coil, 4
4 is a stabilized power supply terminal for other circuits, 45 is a ground terminal, 46 is a resistor, 47 is a high temperature thermistor that is attached to the vaporization heater 24 and detects the temperature of the vaporization heater 24, and 48 is connected in parallel to the thermistor 47. capacitor, 49 and 50 are voltage dividing resistors,
51 is a capacitor connected in parallel to the resistor 50;
52 is the potential between the resistor 46 and thermistor 47
With Va on the inverted side, the potential Vb between resistors 50 and 51
is input to the non-inverting side of the comparator, 53,5
4 is a resistor and a diode interposed between the output of the comparator 52 and the non-inverting input terminal; 55, 5;
6 is a diode whose anode is connected between the resistor 46 and thermistor 47; 57 is a relay coil for controlling on/off of the relay contact 25, which is excited in accordance with the output of the comparator 52; 58 is a diode for canceling back electromotive force, 59 is diode 5
6 is an energy saving switch connected in series, 60 is a terminal for connecting the heat up memory circuit 6 and the heater thermo circuit 4, 61 and 62 are terminals for connecting the heater thermo circuit 4 and the temperature control circuit 5, 63 is a resistor,
64 is a diode whose cathode is connected to the terminal 61; 65 is an inverter consisting of a transistor array IC formed by incorporating several transistors in the same IC; 66 is a timer contact controlled on and off by the timer motor 23; 67; 68, 69
are voltage dividing resistors connected in series between the power supply terminal 44 and the ground terminal 45, and 70 is a resistor 69.
71 is a capacitor, 72, 74, 75, and 76 are resistors connected in series between the power supply terminal 44 and the ground terminal 45, and 73 is connected to the anode of the diode 64. 77 is a thermistor for detecting room temperature connected in parallel with resistor 76, 78 is a resistor, 79 is a capacitor, and 81 is an inverter for the potential on the positive side of capacitor 71. 80 is a resistor connecting the output terminal of the comparator 81 and the non-inverting side input terminal, 82 is the output terminal of the comparator 81 and the power supply terminal. 83 is the relay contact 1
6, a relay coil 84 switches and controls the relay contact 28, and 85 indicates the output terminal of the comparator 81 and the relay coils 83, 8.
86 is a diode whose cathode is connected to the output terminal of the inverter 85, 87 is a capacitor inserted between the resistor 73 and the ground terminal 45, and 88 is a capacitor 8.
A comparator to which the positive potential of the capacitor 71 is input to the non-inverting side and the positive potential of the capacitor 71 is input to the inverting side, 89 is a resistor connecting the output terminal of the comparator 88 and the non-inverting input terminal, and 90 is a power supply terminal. 4
4 and the output terminal of the comparator 88, 91 is a terminal that connects the temperature control circuit 5 and the oscillation circuit 11, 92 is a terminal that connects the temperature control circuit 5 and the heat-up memory circuit 6, and 93 is a terminal. 60 is a diode whose cathode is connected, 94 is a resistor connected to the anode of diode 93, and 95 is terminal 9.
2 is a diode whose cathode is connected; 96 is a resistor connected to the anode of the diode 95; 97 is a resistor connected to the anode of the diode 95;
is a capacitor 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 resistor 99.
A capacitor 101 connects the resistor 98 and the connecting point of the resistor 96, and the anode of the capacitor 101 is connected to the connecting point of the resistors 96 and 98, and the gate is connected to the resistor 99.
PUT, 102 is a diode whose anode is connected to the cathode of PUT 101 and whose cathode is connected to the ground terminal 45, 103 is an inverter connected to the gate of PUT 101, and 104 is a terminal connecting heat-up memory circuit 6 and sequence circuit 8. , 105 is a resistor connecting the power supply terminal 44 and the terminal 104, 106 is a diode whose anode is connected to the terminal 104, and 107 is a diode 106.
A resistor 108 is a capacitor interposed between the resistor 107 and the ground terminal 45. A diode 109 is a diode interposed between the cathode of the diode 106 and the power supply terminal 44. 107, a diode 106, and a capacitor 108, forming a CR timer circuit. 1
10 and 111 are voltage dividing resistors, 113 is resistor 110
A capacitor 114 is connected in parallel with the positive side potential of the capacitor 108, and a comparator 114 has the positive side potential of the capacitor 113 inputted to the inverted side, and the positive side potential of the capacitor 113 is inputted to the non-inverted side. A resistor 115 is a relay coil that controls on/off the relay contact 26, and is interposed between the relay power 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, vibration detection circuit 9 and ignition detection circuit 10, 119 is a resistor connected to the terminal 104, and 120 and 121 are connected in series between the power supply terminal 44 and the ground terminal 45. A voltage dividing resistor 122 connected to and interposed
is a capacitor, 123 is a capacitor connected in parallel to the resistor 121, 124 is a resistor connected to the positive side of the capacitor 123, and 125 is a capacitor 1
A diode is interposed between 22 and the resistor 119, 126 is a resistor connected to the anode of the diode 125, 127 is a resistor that sets the positive potential of the capacitor 122 to the non-inverted side, and sets the positive potential of the capacitor 123 to the inverted side. Comparators input respectively, 12
8 is the output terminal of the comparator 127 and the power supply terminal 4
4, and 129 is the comparator 12.
130 is a diode interposed between the resistor 124 and the output terminal of the inverter 129, and 131 is the inverter 129.
a diode whose cathode is connected to the output terminal of
132 is a resistor that connects the power terminal 44 and the connection point between the resistor 126 and the anode of the diode 131; 133 is a diode that connects the resistor 119 and the power terminal 44; 134 is a cathode connected to the anode of the diode 133; diode, 13
5 is a relay coil that controls on/off the relay contact 33, and is connected to the relay power terminal 43 and the inverter 129.
is connected between the output terminal of the 133' is a diode whose anode is connected to the resistor 132, and the resistors 119, 120, 121, 124, 12
6, 128, 132, capacitor 122, 12
3. Turning off the relay contact 19 when no ignition signal is received from the ignition detection circuit 10 during the operation of a timer circuit, which will be described later, is an essential part of the present invention together with the diodes 125, 130, 131, the comparator 127, and the inverter 129. , constitutes a low-frequency oscillator that causes the ignition transformer 32 to ignite when it does not receive an ignition signal from the ignition detection circuit 10 after the timer circuit has finished operating. 134' is diode 13
The sequence circuit 8 and the ignition detection circuit 10 are connected through the terminal connected to the cathode 3'. 135'
is a capacitor connected between the diode 134 and the ground terminal 45, 136 and 137 are resistors that connect the positive terminal of the capacitor 135' and the output terminal of the comparator 127, and 138 is a resistor 137 whose base and emitter are connected. resistors 136, 137, comparator 135',
Together with the diodes 133 and 134, it constitutes a timer circuit that operates in conjunction with the ignition operation of the ignition transformer 32. 139 is a diode whose cathode is connected to the collector of the transistor 138, 140 is a transistor whose emitter is connected to the anode of the diode 139, and 141 is the transistor 140.
142 is a resistor connected to the base of the 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 receives the collector potential of the transistor 140; 146 is a relay coil interposed between the relay power supply terminal 43 and the output terminal of the inverter 145, and controls the relay contact 19 to be turned on or off. 147 is a terminal that connects the sequence circuit 8 and the vibration detection circuit 9; 148 is the terminal 14;
7 is an inverter whose output terminal is connected, 149 is a diode whose cathode is connected to the input terminal of the inverter 148, 150 is a resistor connected to the relay power supply terminal 43, and 151 is an anode connected to the resistor 150, and whose cathode is connected to the inverter 148. A diode 148 is connected to the input terminal, 152 is a capacitor interposed between the cathode of the diode 151 and the ground terminal 45, and 153 is a diode 15.
1 and the capacitor 152, which is turned off when detecting vibration acceleration of 150 to 200 gal. 155 is the terminal 117 and the diode 149
154 is a terminal connecting the vibration detection circuit 9 and the ignition detection circuit 10;
56 is a main body ground connected to the ground terminal 45 via resistors 157, 158, 159, which causes a voltage drop when flame current flows. 160 is resistance 1
Capacitor connected in parallel with 58, 159, 1
61 is a capacitor connected in parallel to the resistor 159, 162 is a resistor connected to the positive electrode side of the capacitor 161, 163 and 167 are voltage dividing resistors, 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, 166 is a capacitor connected in parallel to the resistor 163, and 169 is the positive terminal side of the capacitor 164. A comparator 168 inputs the potential to the inverting side and the positive potential of the capacitor 166 to the non-inverting side.
9 a resistor connecting the output terminal and the non-inverting input terminal; 170 a resistor connected to the power supply terminal 44;
71 is a diode interposed between the output terminal 134' of the comparator 169, 172 is a diode interposed between the output terminal of the comparator 169 and the resistor 170, and 173 is an input terminal connected to the anode of the diode 172. inverter, 1
74 is a terminal connecting the oscillation circuit 11 and the sequence circuit 8; 175 is a pulse transformer; 176 is a semi-fixed resistor; 177 is a resistor; 178 is a PUT whose anode is connected to the resistor 177 and whose cathode is connected to the pulse transformer 175; is pulse transformer 17
A diode 180 is interposed between the pulse transformer 175 and the terminal 134' so that its cathode is connected to the terminal 134'. Diode, 181 is a capacitor connected in parallel to pulse transformer 175, 182 is PUT1
183 is a capacitor inserted between the anode of PUT 178 and the anode of diode 180; 184 is a capacitor connected in parallel to resistor 182; 185 is diode 1
86 and a resistor connected in parallel to the capacitor 184, 187 and 188 a resistor and a semi-fixed resistor interposed between the anode of the diode 186 and the terminal 91, and 189 a resistor between the anode of the diode 186 and the terminal 104. Interposed resistance, 190,1
91 is a terminal connecting the oscillation circuit 11 and the pump drive circuit 12; 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,
195 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;
199 is a resistor interposed between the semi-fixed resistor 198 and the resistor 196, 200 is a PUT whose anode and cathode are connected in parallel to the resistor 196 and capacitor 197, and 201 is a PUT 200 whose gate and cathode are connected. Capacitor, 202 is a constant voltage diode, 203 and 204 are constant voltage diodes 2
Diode connected in series with 02, 205,2
06, 207 are voltage dividing resistors, resistors 206, 20
7 is a constant voltage diode 202 and a diode 20
3 and 204, and the potential difference of a resistor 207 is further connected to the gate of PUT200.
208 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 interposed between the resistor 209 and the resistor 211. , whose anode is connected to the anode of the diode 208,
Together with the resistor 211 and capacitor 210, this prevents the pump 219, which will be described later, from malfunctioning. 213 is a capacitor connected in parallel to the resistors 209 and 211 and the diode 212; 214 and 215 are the diodes and resistors connected in parallel to the diode 212 and the resistor 211; 216 is a transistor whose base and emitter are connected to the resistor 215; 217 is a resistor, 219 is a pump connected to the collector of transistor 216, 218 is a diode for absorbing the surge generated by pump 219, 22
0 is a capacitor connected in parallel to the pump 219 and the transistor 216, 221 is a resistor, and 222 is a rectifier circuit consisting of a diode bridge that rectifies the alternating current from the terminal 34.

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 operates to generate heat. Due to this heat generating operation, the temperature of the high temperature thermistor 47 rises a.
When the vaporization temperature is reached at this point, 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 inverter 10
The output of 3 becomes H. Therefore, since the inverted side of the comparator 114 is equal to or higher than the non-inverted side, the output of the comparator 114 becomes L, the relay coil 115 is energized, and the combustion blower 27 starts operating with a strong output via the relay contact 26. Furthermore, when the inverter 103 becomes an H output, the capacitor 122 begins to be charged via the resistors 126 and 132 almost at the same time, 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 comparator 127 The output becomes H, the output of the inverter 129 becomes L, and the resistor 1
The capacitor 135' is charged via 36 and 137. As a result, the relay coil 135 is energized, the relay contact 33 is turned on, and the ignition transformer 32 is turned on.
starts working. Also, almost at the same time, the H output of inverter 103 is transmitted to PUT1 via terminal 104.
Although the anode current of 78 is set below the flame current and is input to the oscillation circuit 11 which satisfies the conditions for oscillation, the L output of the inverter 129 causes the terminal 17 to
4 also has an L level potential, and since the output of the inverter 85 is L, the gate potential of the PUT 178 is relatively low due to the resistor 187 and the semi-fixed resistor 188, and the oscillation frequency of the oscillation circuit 11 is relatively high. As a result, this relatively high frequency signal is inputted 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 decreases, so the PUT 200 is turned off, and the current flowing into the gate of the PUT 200 flows into the base of the transistor 216 via the diode 214, so the transistor 216 is turned on and the pump 21 is turned on.
9 is energized and fuel begins to be supplied to the combustion section. After the PUT 200 is turned off, the capacitor 197 starts to be charged again via the semi-fixed resistor 198 and the resistors 196 and 199 after a certain period of time.
PUT200 turns on and transistor 216
is turned off, and power supply to the pump 219 is cut off. When a signal is again input to the base of the transistor 195 via the pulse transformer 175 in this cut-off state, the transistor 195 is turned on and PUT
Since the transistor 200 is turned off, the transistor 216 is turned on and the pump 219 is energized again. Therefore, the pump 219 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 122 is discharged via the resistor 126, so the input potential on the non-inverting side of the comparator 127 becomes L, and the output of the comparator 127 becomes L. Therefore, the output of the inverter 129 becomes H, the relay coil 135 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, changes the inversion side input potential of the comparator 52 to L at time c due to the L output of the inverter 65, and the output of the comparator 52 changes to L. Since the relay coil 57 is demagnetized, the relay contact 25 is turned off and stopped. By this time, the ignition transformer 3
If the flame current is ignited by the operation in step 2, flame current flows from the flame rod 36 to the ground terminal 156, the alternating current component of which is bypassed to the capacitor 160, and only the direct current component flows to the resistors 158 and 159. Due to the constant, the comparator 169 outputs L after a predetermined time delay, and terminals 134' and 143 become L, while terminal 1
54 becomes H. Therefore, L of inverter 103
The output discharges the capacitor 122 and the output of the comparator 127 becomes L. Even if the capacitor 135' is discharged and the transistor 138 is turned on, the output of the comparator 169 remains low until the transistor 138 is turned on.
As a result, the terminal 143 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 the relay contact 19 is maintained 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 and the combustion blower 27 are put into weak operation. 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 11
oscillates at a relatively low oscillation frequency determined by resistor 177, semi-fixed resistor 176, and 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, 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. Due to this H output, the terminals 134' and 143 each become H potential, and the transistor 140 is turned on, but the capacitor 1
35' has finished discharging, so transistor 13
8 is in the OFF state, the output of the inverter 145 is in the L state and the relay coil 146 continues to be excited, but at this time both terminals 174 and 134' are in the H state, so the PUT 178 is in the OFF state and the pump 219 is stopped. , resistance 1 of capacitor 108
07, the output of the comparator 114 becomes H after a delay, the relay coil 115 is demagnetized, the relay contact 26 is turned off, and the combustion blower 27 is stopped at time f. At this time, since the capacitor 135' has finished discharging when the comparator 127 outputs an L signal, 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 stops, the vaporization heater 24 repeats the heat generation action according to the temperature detected by the high temperature thermistor 47.
After the combustion blower 27 stops, the vaporization heater 24
When the temperature reaches the set temperature, the comparator 52 becomes an H output, and the comparator 88 also becomes an H output. Therefore, PUT101 turns on and inverter 103
Since the output of is H, the comparator 114 is L
It becomes an output, and the relay coil 115 is excited and the relay contact 26 is turned on. As a result, the combustion blower 27 is operated weakly again at time g. Then, as the capacitor 122 is charged, at time h, the non-inverting side input potential of the comparator 127 becomes equal to or higher than the inverting side input potential, the comparator 127 outputs an H output, and the inverter 129 outputs an L output. 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 122 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 a misfire occurs again at time j, the ignition transformer 32 is activated again at time k in the same manner as described above, and if the ignition is not ignited at this time, no flame current flows to the main body ground 156, so the output of the comparator 169 becomes H and the terminals 134', 143 becomes H, while the output of the inverter 173 becomes L. As a result, the capacitor 122 is charged again, but during this charging period, the transistor 140 is turned on, and as the capacitor 135' is discharged, the transistor 138 is also turned on, so the input potential of the inverter 145 becomes L and its output becomes H. . Therefore, the relay coil 146 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 controlled to be energized. 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 timer contact 66 is turned off, the comparator 88 is forcibly maintained at L output, and the inverted side input potential of the comparator 52 is held at L via the energy saving switch 59. The relay coil 57 is demagnetized and the vaporization heater 2 becomes H output.
4 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 173 is H and the output of the comparator 114 is also
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, according to the present invention, a capacitor is charged during ignition operation, a timed operation is performed depending on the discharging time of this capacitor, and if a misfire is detected during the timed operation, the ignition is energized by the ON operation of the power switch. The relay that continues to supply power to each element is turned off, and if a misfire is detected after the timed operation ends, the sequence circuit will restart the ignition operation, so if the combustor misfires midway through a simple circuit configuration, It is possible to provide an inexpensive combustion control circuit that is easy to use, highly reliable, and can perform a re-ignition operation.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a combustion control circuit according to an embodiment of the present invention, FIGS. 2 to 8 and 10 to 13 are detailed circuit diagrams of each of the above blocks, and FIG.
The figure shows a potential characteristic diagram of the capacitor 122 and the capacitor 135, where a is the capacitor 122 and b is the capacitor 135. FIG. 14 shows a timing chart of the combustion control circuit. 2...Relay circuit, 8...Sequence circuit, 10...
Ignition detection circuit, 19, 33...Relay contact, 32...
Ignition transformer, 115, 146...relay coil,
119, 120, 121, 124, 126, 12
8,132...Resistor, 122,123...Capacitor, 125,130,131,133'...Diode, 127...Comparator, 129...Inverter, 136,137...Resistor, 135'...Capacitor, 133,134...Diode, 138... transistor.

Claims (1)

[Claims] 1. A relay that is excited by the ON operation of a power switch and continues to supply power to each element, an ignition transformer that is activated by the ON operation of the relay and operation of a sequence circuit, and an ignition detection circuit that detects ignition by this ignition transformer. , the capacitor is charged during the ignition operation of the ignition transformer, and after the ignition transformer finishes the ignition operation, the ignition detection circuit ignites within a predetermined time determined by the discharge of the capacitor. A sequence circuit is provided that turns off the relay contact of the relay when no signal is received, and causes the ignition transformer to perform an ignition operation when no ignition signal is received from the ignition detection circuit after the predetermined period of time has elapsed. Combustion control circuit.