JPH01217126A - Controller for combustion instrument - Google Patents

Abstract

PURPOSE:To prevent the outflow of unburnt fuel due to the malfunction of a control means, by a method wherein the conduction of a solenoid valve is stopped when the operation of an igniting means is stopped during the operation of a timer while the conduction of the solenoid valve is stopped after the time limit of the operation of the timer is elapsed even when the igniting means is being operated. CONSTITUTION:When a solenoid valve opening signal and a sparker operating signal (t1) are outputted, a sparker and a timer circuit 60 are operated and a solenoid valve is opened by a solenoid valve conducting circuit 70. when a burner 12 is ignited at a time (t2), a flame detecting signal is outputted as shown by a chain line A and a sparker operating signal is stopped as shown by another chain line D whereby the operation of a sparker is stopped. The output signals of the timer circuit 60 are outputted as shown by a broken line C and the chain line B continuously thereafter, therefore, the solenoid valve is opened as shown by the broken line E and the chain line F and combustion is continued. When the operating signal of the sparker is stopped at a time (t3) as shown by a full line G, the timer circuit 60 is stopped as shown by the full line H and the conduction of the solenoid valve, which is effected by the solenoid valve conducting circuit 70, is stopped and the solenoid valve is closed as shown by the full line I.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a combustion equipment in which sequences such as energizing a solenoid valve for supplying fuel and operating a sparker for ignition are automatically performed by a microcomputer. Regarding a control device.

[, Prior art] Combustion +ff13 of FF type fan heaters, water heaters, etc.
The operating sequence and combustion conditions at the start of combustion are controlled by a microcomputer, and when the operation start switch is operated, the solenoid valve that controls fuel supply is energized by an open signal from the microcomputer, and ignition is automatically performed. Combustion starts and combustion is carried out under I&appropriate combustion conditions and set temperature. However, if the flame goes out for some reason, a flame detection circuit is installed as a means to stop the supply of fuel gas to avoid gas leaks and ensure safety. If it is no longer detected, the power to the solenoid valve is stopped.

The energizing circuit for this solenoid valve is equipped with a timer circuit in order to supply fuel outside the burner when no flame is detected, such as during ignition. The solenoid valve is energized and fuel is supplied to the burner during the operation.

Furthermore, in combustion equipment that is automatically extinguished during operation to adjust the temperature depending on the combustion temperature, etc., and then ignited again, the solenoid valve is energized to supply fuel each time the combustion equipment is ignited. Therefore, a timer circuit is activated each time the sparker starts operating.

[Problem to be Solved by the Invention] However, if the microcomputer malfunctions and the sparker does not continue to operate even though it has started operating, the timer circuit is activated when the sparker starts operating. At this time, when an opening signal for the solenoid valve is generated at the same time, the solenoid valve is opened and fuel is supplied to the burner. However, since the sparker is not working, ignition does not occur and the fuel leaks out without being ignited, which is extremely dangerous.

The present invention provides a control device for combustion equipment equipped with a microcomputer, which avoids gas leakage when a flame during combustion goes out, and also prevents as much as possible the leakage of unburned fuel even when the microcomputer malfunctions. The purpose of the present invention is to provide a control device for combustion equipment that can perform the following functions.

[Means for Solving the Problems] The present invention provides a solenoid valve that is provided in a fuel supply path that supplies fuel to a burner, supplies fuel to the burner when energized, and stops supplying fuel to the burner when not energized. an ignition means for igniting the burner; a flame detection means for detecting the flame of the burner and generating a flame detection signal; an activation signal to the ignition means and a flame detection signal from the flame detection means; a timer that operates based on the ignition means and operates for a predetermined time after the start of the activation signal to the ignition means, or for a predetermined time during the generation of the flame detection signal and after the stoppage of the activation signal, and the activation signal to the ignition means stops. a timer stop means for stopping the operation of the timer based on an activation signal to the ignition means; a control means for controlling the energization state of the solenoid valve; and an opening signal for the solenoid valve is generated from the control means; and an energizing circuit that energizes the solenoid valve when the timer is operating.

[Operation] In the present invention, when an activation signal is sent to the ignition means, the ignition means is activated, and the timer is activated for a predetermined period of time upon the start of the activation signal. Further, when the control means generates an opening signal for the solenoid valve while the timer is operating, the solenoid valve is energized by the energizing circuit. The solenoid valve supplies fuel to the burner when energized. When the supplied fuel is ignited by the ignition means during the timer operation and ignited, a flame detection signal is generated by the flame detection means. Then, this signal causes the timer to continue operating, and the solenoid valve to continue to be energized.

If the ignition means stops operating while the timer is activated by an activation signal to the ignition means, the timer stop means stops the timer operation. Then, the energization circuit stops energizing the solenoid valve, and the fuel supply to the burner stops.

Additionally, - if there is no ignition in the burner within the timer's operating time limit, the timer's operation will end even if the ignition means continues to operate, and the energization to the solenoid valve will stop, causing the fuel to the burner to stop flowing. Supply will be stopped.

[Effects of the Invention] As described above, in the present invention, when the operation of the ignition means is stopped while the timer is operating, the energization to the solenoid valve is stopped and fuel is not supplied to the burner. Fuel will not leak to burners that are not being cleaned. Further, even if the ignition means is operating, when the operating time limit of the timer has elapsed, the energization to the solenoid valve is stopped, and the fuel supply to the burner is stopped. Therefore, even if the ignition means is repeatedly activated and deactivated due to a malfunction of the control means, the solenoid valve is idle and the supply of fuel is stopped when the ignition means is activated and deactivated, so that unburned fuel does not continue to flow out.

[Example] Next, a combustion equipment control device of the present invention will be described based on an example shown in the drawings.

The gas hot air heater 1 shown in FIG. 2 is composed of a heater main body 20 including a combustor 10, a gas supply path 30, and a control device 40.

The combustor 10 is of a forced air type that sucks air from outside with a combustion fan 11 and supplies it into the combustion chamber 310. The combustion exhaust gas combusted in a ceramic burner 12 passes through a heat exchanger 13. The air is exhausted from the exhaust port 14 to the outside. A sparker 15 as an ignition means is provided near the burner 12, and a thermocouple 16 for detecting flame based on temperature is also provided and sends a signal thereof to a control device 40.

The heater main body 20 uses a convection fan 21 to circulate warm air indoors to introduce indoor air from an air inlet 22, and to mix it with high-temperature combustion gas passing through the heat exchanger 13 of the combustor 10. Heat is exchanged and the hot air is sent indoors from the hot air outlet 23.

The gas supply path 30 is a gas pipe 31 that supplies fuel gas supplied from a not-shown fuel supply source into the combustor 10. This gas pipe 31 is provided with a main solenoid valve 32 and a main solenoid valve 33, which are the solenoid valves of the present invention, from the flow side, and these solenoid valves supply fuel gas to the burner 12 when energized.
The fuel gas is cut off when the power is not energized. Further downstream, a governor valve 34 that supplies fuel gas at a constant pressure, and a proportional valve 35 that adjusts the amount of fuel gas supplied according to the applied current are provided. So 3! An orifice 37 is provided in the bypass pipe 36 to allow a constant flow of fuel gas to pass therethrough.

The fuel gas that has passed through the gas supply path 30 is transferred to the combustor 10 from a nozzle 38 provided in the outside air introduction path 17 of the combustor 10.
supplied within.

As shown in FIG. 1, the control device 40 is a micro controller.

Centering around the computer (hereinafter referred to as CPU) 80,
Flame detection circuit 41, sparker drive circuit 50, timer circuit 6
0, consists of a solenoid valve energizing circuit 70, control bag M, 4
0 is also equipped with an operation switch (not shown), a combustion temperature thermistor, a blowout air temperature thermistor, and a temperature adjustment volume.

The flame detection circuit 41 generates a flame detection signal and transmits it to the CPU 80 and the timer circuit 60 when the thermocouple 16 is heated by combustion in the burner 12 and its output voltage reaches a predetermined voltage or higher. This is the flame detection means of the present invention.

The sparker drive circuit 50, the timer circuit 60, and the solenoid valve energizing circuit 70 are comprised of the circuits shown in FIG. 3, and the timer circuit 60 is equipped with a timer stop circuit 60a.

The sparker drive circuit 50 operates a high voltage generation circuit (not shown) for generating a spark discharge in the discharge gap of the sparker 15. This high voltage generating circuit is connected to a contact point (not shown) of a relay 51, and a terminal 52 is connected to a CPU 8
When the H level control signal from G is transmitted, relay 51
contacts close, and at this time a spark discharge occurs in the gap of the sparker 15.

The timer circuit 60 controls the energization of each solenoid valve by the solenoid valve energization circuit 10, which will be described later, together with cpuao, and generates an output signal of level 1 to energize the solenoid valves. This L level output signal is generated as follows.

When a control signal for operating the sparker drive circuit 50 is transmitted to the terminal 52, the sparker force drive circuit 5 is activated as described above.
0 operates, the transistor 63 is turned on via the resistor 61 and the capacitor 62, and the charge in the capacitor 64 is discharged. Then, the potential of the positive input terminal 65a of the comparator 65 decreases and becomes lower than the reference voltage on the negative input terminal 65b side formed by the resistors 66a and 66b, and the comparator 65 outputs the level I.

Here, when the capacitor 62 is charged by the H level control signal from the terminal 52, the transistor 63
The base current of the transistor 63 no longer flows through the O
It becomes FF'. Therefore, the capacitor 64 is discharged only at the beginning of the transmission of the control signal to the sparker drive circuit 50, and thereafter the capacitor 64 is only charged. Therefore, by charging the capacitor G4, the positive input terminal G5a
The output of the comparator 65 is at L level for a predetermined period of time until the potential becomes higher than the reference voltage.

In this embodiment, especially when the CPU 80 malfunctions and repeatedly generates and stops the activation signal for the sparker 15 and further generates an open signal for each electromagnetic valve, each electromagnetic valve becomes open and the fuel gas Because of the leakage, the fuel supply is stopped when the sparker 15 is not in operation, and there is no possibility of ignition.
In order to reduce the amount of outflow, a timer stop circuit Boa is provided.

This timer stop circuit 60a is timer stop means of the present invention, and is a switching circuit using a transistor 67. Since this transistor 61 is a PNP type unlike other transistors, the CP signal transmitted to the terminal 52
When the sparker activation signal from IJ80 goes to L level,
The potential difference between the emitter and base of the transistor 67 becomes large and turns ON. Therefore, when the sparker activation signal is stopped, it is turned ON and charges the capacitor 64. This lick timer circuit 60 outputs an H level.

On the other hand, the positive input terminal 65a of the converter 65 is provided with a switching circuit including a transistor 68.
When the flame detection signal from the flame detection circuit 41 is transmitted to the terminal 68a, the potential of the positive input terminal 65a is lowered, and the output of the comparator 65 is set to L level.

If a flame is thereby detected, each solenoid valve can be opened.

The solenoid valve energizing circuit 70 is connected to the timer circuit 60 (CI)
The relay 11 is energized based on a control signal from the relay 80, and each electromagnetic valve connected to a contact (not shown) is energized. In this solenoid valve energizing circuit 70, the transistor 1
The output of the timer circuit 60 is transmitted to the base of the CPU 2 via a resistor 73, and the solenoid valve opening signal from the CPUAO is transmitted to the terminal 74. When an L level signal is input to the transistor 72 and an electromagnetic valve opening signal is input to the terminal 74, the transistor 75 is turned on and energizes the relay 71 to energize each electromagnetic valve. Therefore, even if the solenoid valve opening signal is transmitted to the terminal 14, if the output of the timer circuit 60 is at level (2), each solenoid valve is not energized.

With this solenoid valve energizing circuit 70, for example, when the flame in the burner 12 goes out and cannot be detected, the transistor
8 is turned off, the potential of the positive input terminal 65a becomes high, and the output of the timer circuit 60 reaches the summer level, so that each solenoid valve is not energized. Therefore, when the flame is extinguished, the fuel gas will not flow out unburned.

The cpuao operates the combustion fan 11. according to a predetermined operating sequence. 'Sparker drive circuit 50, convection) gamma 21,
The main solenoid valve 32, the main solenoid valve 33, and the proportional valve 35 are energized, and based on signals from the combustion temperature thermistor, outlet air temperature thermistor, temperature control volume, and thermocouple 16 (not shown), Burns and blows air.

Next, the operation of the gas hot air heater 1 of this embodiment having the above configuration will be explained based on FIGS. 4 and 5.

When the user presses the operation switch, the combustion fan 11 rotates, and when the rotation speed reaches a predetermined number, the sequence by CI) U3O is started.

First, when a solenoid valve opening signal and a sparker activation signal are issued at time t1, each circuit is activated based on these signals. The solenoid valve signal is an open signal (open at 31), and 1
If there is one sparker activation signal (YES in S2),
At the same time as the sparker 15 is activated (S3), the timer circuit 60 is activated and the output becomes L level (54). As a result, each electromagnetic valve is energized by the electromagnetic valve energizing circuit 70 and becomes open (S5).

When the burner 12 is ignited at time t2 during the output time period T2 of the timer circuit 60 due to the operation of the sparker 15 (No in S6 and YES in S7), the flame detection signal becomes an H level signal as shown by the chain line A. Under normal conditions, the flame detection signal causes the sparker activation signal to stop as shown by the dashed line B, and the sparker 15 stops operating (S8), after which the output signal of the timer circuit 60 continues as shown by the broken line C and the broken line B. Since the output is at the L level, the solenoid valve is opened as shown by broken lines E and F, and combustion continues (S9).

If there is no ignition even if the sparker 15 operates during the output time limit T2 of the timer circuit 60 (NO in S7 and NO in S10
(YES), sparker 15 until output time limit T2 elapses.
is activated, and each solenoid valve continues to be open.

When the activation signal of the sparker 15 stops as shown by the solid line G at time t3 during the output time limit T2 of the timer circuit 60 (NO in S10), the timer circuit 60 is activated by the timer stop circuit 60a as shown by the solid line H. The output signal is stopped and becomes an H level output signal. Then, the electromagnetic valve energizing circuit 10 stops energizing each electromagnetic valve, and the electromagnetic valve is opened as shown by the solid line I (Stl).

As described above, conventionally, even if the sparker activation signal to the sparker drive circuit 50 stops, one solenoid valve remains open until time t4 when the output time limit 12 of the timer circuit 60 has elapsed. In the example, the open state can be established at time T1 until time t3 when the activation signal to the sparker drive circuit 50 is stopped.

Therefore, if the CPU 8G malfunctions and generates a solenoid valve open signal and then repeatedly generates a sparker activation signal, and reliable ignition is not performed, the amount of fuel gas flowing out can be reduced. .

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the main parts of the control device of this embodiment, Fig. 2 is a configuration diagram showing the gas hot air heater of this embodiment, and Fig. 3 is a partial circuit showing the control device of this embodiment. 4 are time charts for explaining the operation of this embodiment, and FIG. 5 is a flowchart for explaining the operation of this embodiment. In the figure, 32... Original solenoid valve, 33... Main solenoid valve, 15
...Sparker (ignition means), 41...Flame detection circuit (
flame detection means), 60... timer circuit (timer, timer stop means), 70... solenoid valve energizing circuit, 80... microcomputer (control means).

Claims (1)

[Claims] 1) an electromagnetic valve that is provided in a fuel supply path that supplies fuel to the burner, supplies fuel to the burner when energized, and stops supplying fuel to the burner when not energized; an ignition means for igniting the ignition; a flame detection means for detecting the flame of the burner and generating a flame detection signal; , a timer that operates for a predetermined time after the start of the activation signal to the ignition means, or for a predetermined time while the flame detection signal is being generated and after its stop; and when the activation signal to the ignition means stops, the ignition means a timer stop means for stopping the operation of the timer based on an operation signal sent to the timer; a control means for controlling the energization state of the solenoid valve; and an opening signal for the solenoid valve is generated from the control means and the timer is activated. a control device for combustion equipment, comprising an energizing circuit that energizes the solenoid valve when the electromagnetic valve is in operation;