JPS6116893B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control circuit for a combustion device, and particularly to a control circuit configured to turn off the main power and disable the ignition operation when the ignition operation reaches a predetermined number of times.

An example of this type of control circuit is shown in FIG. In the figure, 1 is a power supply, 2 is a power fuse, 3 is a power switch, 4 is an anti-corrosion power supply and dry firing prevention circuit, 5 is an indicator lamp, 6 is a corrosion prevention and dry firing prevention detection electrode, and the can body (not shown). protrudes inward. 7 is a ground connected to the can body, 8 is an ignition detection circuit incorporating a count IC, 9 is a reset contact for the count IC connected to the ignition detection circuit 8, and 10 is connected to the ignition detection circuit 8. 11 is a flame current detection electrode; 12 is an auto-cut for water temperature that detects the temperature of water inside the can and opens when the temperature exceeds a predetermined temperature; 13
14 is a temperature fuse provided in the exhaust stack to prevent abnormal heating due to abnormal combustion, etc.; 15 is a pilot lamp that lights up during normal operation; 16 is a first relay provided in parallel with the pilot lamp 15 and in series with the hot water temperature thermostat 17, and has a reset contact 9 and a contact 8.
Holds when energized. 19 is an output contact of the count IC which is formed to open when the count IC exceeds a set value, and is connected in series with the parallel circuit of the pilot lamp 15, the first relay 16, and the hot water temperature thermostat 17. . Reference numeral 20 denotes a dry firing prevention contact connected in series with the output contact 19, and is configured to open when dry heating is detected by the anticorrosion power supply/dry firing prevention circuit 4. 21 is an anti-seismic automatic fire extinguishing system, and 22 is a combustor preheating heater, which is connected in series with a preheating thermostat 23 which has two contacts and detects the preheating state of the combustor, and one end of this series circuit is connected through a contact 18. It is provided in parallel with the ignition detection circuit 8. 24 is a combustion blower, 25 is a contact that operates in conjunction with a second relay 27 to be described later to form two contacts, and 26 is a delay thermostat connected to the one contact side of contact 25, which increases the temperature in the water heater. It is closed when the set value is reached, and even after the power switch 3 is turned off, it is closed until the temperature falls below the set temperature to operate the combustion blower 24 and discharge the fuel remaining in the combustor. has been done. The combustion blower 24, the contact point 25, and the delay thermostat 26 are connected in series, and are connected in parallel to the anti-corrosion power supply/dry firing prevention circuit 4. 27 is the aforementioned second relay, one end of which is connected to the power supply 1 through contacts 28 and 18, and the other end connected in parallel with a timer contact 29 and a contact 30 that is closed when flame current is detected. It is connected in series to the circuit and is formed so as to close the counting contact 10 when energized. Reference numeral 31 denotes a wind pressure switch, which is connected in series with the contact 28 and forms a bypass circuit with one contact of the preheating thermostat 23. 32 is a timer contact that operates simultaneously with the timer contact 29; 33 is a high-pressure discharge device for ignition;
4 is a combustion confirmation lamp provided to be lit during ignition operation and combustion; 35 is a rectifying element; 36 is a timer circuit for setting the ignition time; the timer contacts 29 and 32 are opened at the set time; A fuel supply pump (not shown) is connected.

To briefly explain the operation of the control circuit configured in this way, when the water level inside the can is sufficient, it is detected by the anti-corrosion power supply/dry firing prevention circuit 4, the indication is displayed by the indicator lamp 5, and the dry firing prevention contact 20 is closed. will be accomplished. Next, by closing the power switch 3, the pilot lamp 15 lights up under normal conditions, and
Contact 18 and reset contact 9 are closed by second relay 16, and preheater 22 is energized to heat the combustor. When the combustor temperature reaches the set point, the preheat thermostat 23 reverses and the second relay 2
7 is energized and the contact 28 is closed, and the contact 25
is reversed and the combustion blower 24 is operated, and the count contact 10 is closed and the second count IC is activated.
The operation of the relay 27 is counted. When the wind pressure from the combustion blower 24 becomes sufficient, the wind pressure switch 3
1 is reversed, the ignition time setting timer circuit 36 is energized via the rectifying element 35, the fuel is supplied to the combustor, vaporized, mixed with combustion air, and then ignited by the high pressure discharge device 33. The delay thermostat 26 is closed when a predetermined temperature is reached due to combustion. To stop the operation, it is enough to open the power switch 3, but even after the power switch 3 is opened, the combustion blower 24 continues to operate and discharges unburned gas, and then stops when the temperature falls below the predetermined temperature of the delay thermometer 26. do.

When the ignition operation fails in this control circuit and the operation is repeated, the number of operations is input as a pulse to the count IC built in the ignition detection circuit 8, and when the number of times exceeds the set value, the count IC The output contact 19 of is opened, and the ignition operation is stopped. Therefore, dangers such as explosion due to residual gas can be prevented and safety is high.

However, in the conventional control circuit, as in FIG. The number of operations of 27 is detected by the ignition detection circuit 8 by opening and closing the counting contact 10, and the second relay 27 has a contact 18 on the power supply 1 side for supplying the power voltage to the second relay 27. A first relay 16 is provided, a hot water temperature thermostat 17 is connected in series with the first relay 16, and the output contact 19 of the ignition detection circuit 8 is connected to the series circuit of the first relay 16 and the hot water temperature thermostat 17. However, as shown in Fig. 1, the reset contact 9 is not connected to be opened or closed by the first relay 16, and the count IC can be reset by resetting the power switch 3. It started to be done by

Therefore, in the conventional control circuit, the water temperature is ignited, the water temperature rises, and when the water temperature reaches a predetermined temperature, the water temperature thermostat 17 is turned off, and then turned on again when the water temperature falls. When the operation is repeated, this hot water temperature thermostat 17 turns ON.
As the second relay 27 turns off, it turns on and off, opening and closing the counting contact 10. In other words, the hot water temperature thermostat 17 is ON-OFF.
When the operation is performed, the number of ON-OFF operations becomes the number of openings and closings of the counting contact 10, and as a result, the number of openings and closings of the counting contact 10 associated with the ON-OFF operation of the hot water temperature thermostat 17 becomes the number of openings and closings of the counting contact 10 as is. It was counted, and the count continued.

As a result, the count IC counts the set number of times and opens the output contact 19, which causes the ignition detection circuit 8 provided for ignition safety to become inoperable and stop the combustion operation midway. It was causing a problem. Therefore, when maintaining the temperature of the water inside the can for a long time, the water temperature thermostat 17 turns on and off many times, making it extremely difficult to reset the power switch 3 many times. The problem was that it was troublesome and time-consuming.

The present invention has been made in view of the above points, and provides a control circuit for a combustion device that eliminates the conventional problems by configuring the circuit so that the count IC is reset even when the hot water temperature thermostat is turned on. It is something to do.

To this end, the present invention provides a counting IC using a first relay connected in series with a hot water temperature thermostat.
The reset contact of the counter IC is closed, and the counter IC is reset in conjunction with the operation of the hot water temperature thermostat.

Hereinafter, one embodiment of the present invention will be described based on FIGS. 1 and 2. Incidentally, FIG. 2 shows the internal configuration of the ignition detection circuit 8 including the count IC shown in FIG. Yes, contacts 9 and 10 are the first
These are similar parts located at the same parts as those with the same reference numerals in the figure.

In the figure, 41 is a capacitor connected to the reset contact 9, 42 is a resistor, 43 is a diode, 44 is a transistor, and the base resistor 42 is connected to
The emitters are each connected to a secondary coil. 45 is a capacitor, 46 is a diode, 47
is a resistor connected in series with capacitor 45, 48
is a transistor, 49 is a relay connected to the collector of the transistor 48, 50 is a count IC whose clear terminal a is connected to the collector of the transistor 44 and a capacitor 45, and whose output terminal c is connected to the base of the transistor 48. Further, a signal from a chattering prevention circuit, which will be described later, is input to the clock terminal b. 51 is a diode, 52 is a capacitor, 53 is a resistor connected in parallel with the capacitor 52, 54 is a thyristor whose cathode side is connected to the resistor 53 and the clock terminal b of the count IC 50, and 55 is the count contact 10 and the thyristor 54. Resistors 56 and 57 inserted between the two are resistors. And capacitor 52, resistor 53,5
5, 56, 57 and the thyristor 54 constitute a chattering prevention circuit. Note that G and H in FIG. 2 indicate points G and H in FIG. 1.

The operation of the ignition detection circuit having such a configuration will be explained.

When the power switch 3 in Figure 1 is closed, the power supply voltage rises as shown at A in Figure 4
The voltage of clear terminal a of IC50 is capacitor 45
It rises to the power supply voltage through capacitor 45.
is charged through the resistor 47, so B in Figure 4 A
After the voltage rises to the power supply voltage, it gradually decreases. In this manner, when the power switch 3 is closed, the clear terminal a of the count IC 50 temporarily becomes "H" and the count IC 50 is automatically reset. At this time, the output terminal c of the count IC50
is “L” as shown in FIG.
is turned on, the relay 49 is also energized, and if there is no abnormality in the combustion system, the ignition detection circuit is on standby in this state.

If the ignition fails during the ignition operation,
If the fire is extinguished due to fuel shortage during combustion, the second relay 27 in the control circuit is opened and the contact 10 is closed. Conventionally, the operation of the counting contact 10 was directly used as a clock input for the counting IC, but in this case, the chattering of the counting contact 10 was counted and the counter advanced too much, causing malfunction. Therefore, in this embodiment, a chattering prevention circuit is configured, and the signal generated by the operation of the counting contact 10 is counted via the thyristor 54.
It is input to clock terminal b of IC50.
Now, when the counting contact 10 is closed, the capacitor 52 is charged via the resistor 55 as indicated by D in FIG. When this potential reaches the gate potential of the thyristor 54 (shown by the dotted line in the center of FIG. 4), the thyristor 54 is turned on and the capacitor 52 is connected to the resistor 54.
3, a signal as shown in c in FIG. 4 is obtained at the cathode of the thyristor 54, and the clock pulse is being received and the counter increments once.
Once the thyristor 54 is turned on, it remains turned on until the counting contact 10 is opened, so even if the counting contact 10 is chattering, the timing of the clock pulse output is slightly delayed as shown in D' and C' in Figure 4 (ro). However, there is no effect on the counting operation due to chattering. In this way, when the counting contact 10 closes, the count advances one by one, and the output terminals d, e, f of the count IC 50 sequentially change from "L" to "H" (the third
(see figure). After resetting the count IC 50, if the ignition fails three times or is extinguished halfway, the count contact 10 opens and closes three times, and the counter advances three times and the count IC
50's output terminal c changes from "L" to "H",
The transistor 48 is turned off, the relay 49 is de-energized, the output contact 19 in the control circuit is opened and closed, and the combustion device's stop 15 and combustion confirmation lamp 34 are turned off. When restarting the operation, open the power switch 3 once and close it again to set the count IC5.
Since 0 is automatically reset as described above, operation is possible.

On the other hand, when the ignition is performed normally and the water temperature reaches the set temperature, and the hot water temperature is controlled by the ON-OFF operation of the hot water temperature thermostat 17, the hot water temperature thermostat 17 is turned on and the temperature in the control circuit is controlled. When the first relay 16 is closed, the reset contact 9 interlocked with this relay 16 is also closed,
Since the potential at point F in Figure 2 drops from the power supply voltage to the ground potential, this signal
The voltage signal E in FIG. 4C differentiated by 2 is applied to the transistor 44, and the transistor 44
Since the capacitor 45 is turned on and discharged, the potential of the clear terminal a of the count IC 50 becomes "H" temporarily as shown by B' in FIG. 4C, and the count IC 50 is reset. However, when the transistor 44 is turned off, the capacitor 45 becomes the resistor 4
7, the potential gradually decreases to "L" potential and enters a count standby state.

In this manner, the count IC 50 is reset even when the hot water temperature thermostat 17 is turned on, so that the hot water temperature can be controlled for a long time regardless of whether the thermostat 17 is turned on or off.

In addition, since the count IC is reset when the hot water temperature thermostat 17 turns ON, in this embodiment, even if the third ignition is extinguished midway through, the combustion operation of the combustion device will not stop even if the hot water temperature thermostat turns it off. Because of this, it is only possible to repeat the operation two and a half times. However, the count IC used here can be operated repeatedly up to 8 and a half times, and the number of repeated operations can be arbitrarily selected within the above range in consideration of safety, usability, etc.

As described above, according to the present invention, the first relay starts counting by the conduction of the hot water temperature thermostat.
Since the IC is reset, the hot water temperature can be continuously controlled by the hot water thermostat for a long time, and the temperature control operation described above is extremely simple, making it possible to provide a control circuit for a combustion device with high practical value. .

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing an embodiment of a control circuit for a combustion device according to the present invention, FIG. 2 is a circuit diagram showing an internal configuration of an ignition detection circuit in the control circuit for the combustion device described above, and FIG. Timing chart of the count IC in the ignition detection circuit as above, Fig. 4A,
B and C show the voltage characteristics corresponding to the operation of the control circuit at each point A, B, C, C, and E shown in Figure 2, and A shows the voltage characteristics at points A and B when the power supply is closed. B is a voltage characteristic diagram at points C and D when the counting contact is closed, and C is a voltage characteristic diagram at points E and B when the hot water temperature thermostat is turned on. DESCRIPTION OF SYMBOLS 1... Power supply, 8... Ignition detection circuit, 9... Reset contact, 16... First relay, 17... Hot water temperature thermostat, 19... Output contact, 27... Second relay 50
…Count IC.

Claims (1)

[Scope of Claims] 1. An ignition detection circuit 8 having a counting contact 10 and a reset contact 9 and incorporating a counting IC 50 that performs counting and resetting when these contacts are closed, and an ignition detection circuit 8 provided in parallel with the detection circuit. a first relay 16 which is energized when the main power supply is closed and closes the reset contact; and a hot water temperature thermostat 17 which is installed in series with the relay and controls the temperature of the hot water.
and a second relay 27 that is supplied with power through the contact 18 that is closed when the first relay 16 is energized and closes the ignition circuit, and is responsive to the energization operation of the second relay 27. to close the counting contact and close the first relay 16.
and a hot water temperature thermostat 17, and an output contact 19 that is opened when the count IC 50 counts a set value. 2 The ignition detection circuit 8 connects a capacitor in parallel to a reset contact 9 provided in parallel with the power supply.
41 , a transistor 44 which becomes conductive due to the charging voltage of the capacitor 41 when the reset contact 9 is closed, and a capacitor 45 forming a parallel circuit with the transistor 44 and connected in series to the power supply of this circuit. A control circuit for a combustion device according to claim 1, comprising: a count IC 50 having a clear terminal a connected in series to the other end of the parallel circuit. 3. A control circuit for a combustion device according to claim 1 or 2, wherein the ignition detection circuit 8 is provided with a chattering prevention circuit. 4 The anti-chattering circuit is a thyristor whose cathode side is connected to clock terminal b of the count IC.
54 , a resistor 53 provided in series with the thyristor 54 across the contact between the thyristor 54 and the clock terminal b , and the thyristor 54 and the resistor 53.
A capacitor 52 provided in parallel with the capacitor 52, these parallel circuits, and the counting contact 10 of the counting IC 50 .
a resistor 55 provided between the clock terminal b, and a signal generated by the charging voltage of the capacitor 52 when the thyristor 54 conducts when the counting contact 10 is closed is inputted to the clock terminal b . A control circuit for a combustion device according to claim 3.