JP2563470B2 - Combustion safety device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device for a combustion fan control circuit of a combustion appliance such as a gas water heater.

2. Description of the Related Art In recent years, an automatic gas supply device having a combustion fan has become popular in homes in order to obtain a comfortable life. Range hoods with a built-in water heater have also become widespread in order to make effective use of the kitchen space. In this system, a water heater is installed in a conventional range hood, and the air required for its combustion is taken in by a ventilation fan of the range hood, and the exhaust air is discharged to the outside together with the air in the living room. This control has a control circuit in the range hood, and starts combustion after detecting the operation of the ventilation fan by a wind pressure switch or the like,
In the event that the motor lead wire of the ventilation fan is disconnected, the sequence is such that the ventilating fan is not activated by the wind pressure switch and the combustion is stopped. This is because there is an automatic damper that automatically opens with the wind pressure of the ventilation fan in the exhaust duct of the range hood in order to prevent outdoor invasion of wind, rain and cold from the outside when the range hood is stopped. When the exhaust fan is not operating during one combustion, the target damper is not opened and the combustion exhaust gas flows back into the living room, so the sequence is to prevent it. At the same time, when the ventilation fan stops, the air required for combustion is not obtained and incomplete combustion occurs, and a lot of toxic gases such as carbon monoxide are generated, which will flow into the living room. It is a sequence.

Problems to be Solved by the Invention These sequences are mainly performed by a microcomputer (hereinafter referred to as a microcomputer). That is, when the hot water tap is opened, the fan of the ventilation fan is operated, the operation of the fan is confirmed, the igniter is operated, the solenoid valve is opened, and the combustion is monitored by a pre-programmed sequence. .

However, since the microcomputer is made extremely small, it is easy to malfunction due to excessive noise such as power supply noise or unexpected power supply noise, and there is a strong possibility that it will be damaged by static electricity. Even if the fan of the ventilation fan stops, if the microcomputer cannot detect the stop of the fan due to these phenomena, the toxic exhaust gas fills the living room as described above, which is very dangerous.

The present invention solves the problems of the prior art as described above, and provides a device that operates safely even if a microcomputer or the like fails or malfunctions.

Means for Solving the Problems In order to solve the above problems, the present invention provides a combustion instrument having a burner, a solenoid valve for controlling fuel supplied to the burner,
A fan motor for supplying air required for combustion of the combustion appliance, a fan operation detector for monitoring whether the fan motor is operating normally, and a fan when the fan motor is operating normally. A combustion control main element that opens a solenoid valve to start combustion by a fan normal operation signal of an operation detector and closes the solenoid valve when the fan motor fails, and the combustion control main element and fan. And a valve closing circuit for closing the solenoid valve when the motor fails.

Effect Even if the combustion control main element such as the microcomputer fails and the fan of the ventilation fan fails by the above means, the combustion is stopped by the valve closing circuit that closes the electromagnetic valve, and the exhaust gas does not flow back into the living room. To be prevented.

EXAMPLE An example of the present invention will be described below.

FIG. 1 shows a circuit diagram which is an embodiment of the present invention. Second
The figure shows a top view and side view of the device, and FIG. 3 shows an actual installation view.

In FIG. 1, 1 is an AC100V power supply, 2 is a temperature fuse, 3 is a triac for driving a ventilation fan, 4 is a photo triac, 5 is a fan motor for performing ventilation in a living room and intake and exhaust of a combustor, and 6 is a power transformer. , 7 are capacitors 8
Is a DC power supply of 5V, 9 is a ventilation switch, 10 is a hot water supply switch, 11 is an operation microcomputer, 12 is a wind pressure switch which is a fan operation detector for detecting the operation of the fan motor, 13 is a heat exchanger 25 of the water heater A Water flow switch installed in the water flow path to,
14 is a safety transistor 15 is an igniter of the burner 24, 16 is a solenoid valve for supplying gas to the burner 24, 17, 18, 19 are transistors, 20 is a capacitor, 21 is a transistor 22 is a combustion control main element microcomputer . 23 is a faucet. The water heater A is built in the range hood 28 through a case 29, and a duct 30 is used to provide an intake port 5a for the fan motor 5 of the ventilation fan.
And the combustion air is sucked from the air port 31. 26 is an automatic damper installed at the exhaust port of the ventilation fan, and 32 is an intake port of the range hood.

The transistors 19 and 21 and the capacitor 20 form the valve closing circuit 27 of the solenoid valve 16.

In the above embodiment, when used as a ventilation fan, when the ventilation fan switch 9 is pressed, the operation microcomputer 11 activates the photo triac 4, the triac 3 becomes conductive, the fan motor 5 rotates, and air is introduced into the range hood 28 from the intake port 32. Is sucked, the automatic damper 26 is opened and discharged to ventilate the living room. No combustion occurs at this time. Next, when using the hot water supply device, when the hot water supply switch 10 is pressed, the hot water supply output of the operation microcomputer 11 becomes H and the combustion standby operation is performed. If the faucet 23 is opened in this state, the microcomputer 22 is activated by being detected by the water flow switch 13. First, it is detected whether the wind pressure switch 12 of the fan motor 5 is short-circuited. However, no detection is performed because the fan motor 5 may already be operating, or the wind pressure switch 12 may be on for about 3 minutes after the operation. If there is no short circuit failure, the fan triac 4 and the photo triac 4 are operated to rotate the fan motor 5. Then, the fan motor 5 is operated without fail and the wind pressure switch 12 detects that the wind pressure is generated, and then the igniter 15 is activated, and then the solenoid valve 16 is opened to burn the burner 24. At this time, the combustion stop circuit, which is the valve closing circuit 27,
Since the wind pressure switch 12 is closed, the base of the transistor 21 is H, the collector is L, the collector of the transistor 19 is H, and the transistor 19 is in the OFF state, which is not involved in driving the solenoid valve 16. However, in the unlikely event that the microcomputer 22 breaks down and the fan motor 5 breaks down or the like, in the case of the present invention, which could not be done in the conventional case, when the wind pressure spread switch 12 is turned off, the base of the transistor 21 becomes After a certain period of time when the capacitor 20 is charged to L, the base of the transistor 19 becomes H and the collector becomes L to turn off the transistor 18 and close the solenoid valve 16. Therefore, these valve closing circuits 27 enable the microcomputer that is the main combustion control element.
If the 22 fails, the combustion appliances remain safe.

As described above, according to the present invention, in the case where the combustion fan for obtaining the air required for the conventional combustion fails and the control device such as the microcomputer fails, the fan motor may be stopped. There is a risk that exhaust gas will flow back into the living room without continuing combustion, but the output of the fan operation detector is detected by the valve closing circuit and combustion is stopped, so it is safe and truly highly practical. A combustion instrument is provided.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a combustion safety device of the present invention,
FIG. 2 is a configuration diagram of the gas supply, oil supply, and exhaust circuit, FIG. 3 is a cross-sectional view of a range hood with a built-in water heater in which the device is implemented, FIG. 4 is a cross-sectional view of the same side, and FIG. 5 is the same side. FIG. 5 ... Fan motor, 12 ... Wind pressure switch (fan operation detector), 16 ... Solenoid valve, 22 ... Microcomputer (combustion control main element), 27 ... Closed circuit.

Claims (2)

(57) [Claims] 1. A combustion device having a burner, a solenoid valve for controlling fuel supplied to the burner, a fan motor for supplying air necessary for combustion of the combustion device, and a fan motor which operates normally. A fan operation detector that monitors whether or not the fan motor is operating normally, and the solenoid valve is opened by the fan normal operation signal of the fan operation detector to start combustion, and A combustion control main element that closes the solenoid valve when the fan motor fails, and a valve closing circuit that closes the solenoid valve when the combustion control main element and the fan motor fail. Combustion safety device having. 2. The combustion safety device according to claim 1, wherein the fan motor also serves as ventilation in the living room.