JPS6310331B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a combustion control device used in gas combustion appliances, particularly a solenoid valve drive circuit and an igniter circuit.

Configuration of conventional example and its problems For example, the conventional hot air fan heater 1 shown in FIG. 1 is equipped with a control circuit shown in FIG. When the solenoid valve 2 is left open due to a failure in the drive circuit 3, raw gas leaks out when the combustion flame blows out, and many efforts have been made to prevent a serious accident.

One of them is an AC coupled drive system for the solenoid valve 2. This is to apply the voltage necessary to keep the solenoid valve open via the pulse transformer 4. That is, the solenoid valve 2 is driven by exciting the primary side of the pulse transformer 4 with a signal from the combustion sensor, and opening the solenoid valve 2 with a secondary voltage. Therefore, even if a transistor or the like that excites the primary side has a shot failure or an open failure, the pulse transformer will not be energized, and no voltage will be supplied to the solenoid valve, resulting in a fail-safe circuit that will not open. In addition, this excitation is generally performed at a frequency of 20KHz to 40KHz in order to perform it most efficiently.

On the other hand, combustion appliances require an ignition circuit 5, which charges up a capacitor and discharges it with a transistor or the like through the primary side of a high voltage generating transformer, creating a high voltage spark of 10-odd KV on the secondary side. It is something that occurs. Generally, this charge up requires 100V or more, but since this igniter is controlled by a circuit with a voltage of several to several tens of volts, this
For voltages above 100V, another transformer 6 was used to boost the voltage of the control circuit to above 100V.

Additionally, a combustion indicator lamp 7 is provided to indicate whether or not the combustion appliance is burning normally, but if the solenoid valve is forcibly opened at the start of combustion, In order to distinguish between the period in which the fuel is being held and the period in which the combustion is indicated by the combustion detection by the combustion sensor after the forced holding is finished, the combustion indicator lamp is blinked by the oscillator 8 during the forced holding. Therefore, an oscillator 8 was required to blink the combustion indicator lamp 7 at the start of combustion.

OBJECT OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks by omitting the transformer that supplies the voltage necessary for the igniter.
Also, the oscillation circuit that drives the combustion indicator lamp is omitted,
The purpose is to improve economy and reliability.

Structure of the Invention In order to achieve the above object, the first structure of the present invention is to drive an igniter using the voltage generated in a pulse transformer for driving a solenoid valve, thereby eliminating the conventional transformer for driving the igniter. The second configuration uses the igniter's current to blink the combustion indicator lamp at the start of combustion, and eliminates the oscillation circuit.

DESCRIPTION OF THE EMBODIMENTS FIG. 3 shows a schematic diagram of the present invention. 9 solenoid valves for combustion appliances, 1 pulse transformer to drive them
0, the igniter is shown at 11. Also, set the combustion indicator lamp to 1.
Shown in 2. The driving voltage of the igniter 11 is taken from the spike voltage on the primary side of the pulse transformer 10, and the current of the combustion lamp 12 is arranged in its current path.

13 is an AC 100V power supply, 14 is a switch linked to a power supply (not shown in this attached drawing),
15 is a power transformer, 16 is a rectifier, and 17 is an energizing lamp. Further, 18 is an oscillation circuit, 19 is a timer circuit, and 20 is a combustion detection circuit. 21 is a driving transistor for a pulse transformer, 22 is a transistor for stopping an igniter, 23 is a Schochley diode, 24 is a capacitor, and 25 is a high voltage transformer. 26 is a diode, 27 is a combustion confirmation lamp, and 28 is a resistor. Also, 29 is a pulse transformer, 30 is a diode, 31 is a capacitor,
32 is a diode, and 33 is a solenoid valve disposed in the fuel passage of the combustion appliance.

These operations will be explained along with the operation of the instrument.
First, when the gas cooker is opened, the switch 14 linked to it is turned on. Then, a voltage reduced to about 10 V is supplied to the control circuit by the power transformer 15 and the rectifier 16, and the energizing lamp 17 lights up. Also, the oscillation of 18 is started, and the timer 19 causes the transistor 21 to oscillate regardless of the resistance value of the sensor a, and the pulse transformer 2
9 is excited. The excited pulse transformer generates an alternating current voltage on the secondary side, which is rectified by a diode 30 and a capacitor 31 to become a direct current voltage that passes through a solenoid valve 33, which opens and transfers the gas to a burner (not shown). ). Also, 29 at the same time
The pulse transformer uses a flyback method for AC coupling to increase the transmission efficiency on the primary side.
A high voltage of 100-odd volts is generated and is charged up to 24 capacitors through 28 resistors, 27 combustion lamps, and 26 diodes. When the charge voltage reaches the breakover voltage of the Shockley diode of No. 23, the Shockley diode of No. 23 becomes conductive, and the charge voltage of the capacitor becomes 2.
It is discharged through the high voltage transformer No. 5, generates a high voltage of more than 10 KV on the secondary side of the high voltage transformer, and the spark voltage is sparked in the raw gas near the burner. Therefore, the raw gas is ignited and combustion begins. or,
The Schottley diode is turned off again due to the voltage drop to the capacitor 24 discharged by the Schottley diode 23, and the pulse transformer voltage 29 is supplied to the capacitor 24, and the capacitor 24 is charged up. When the breakover voltage is reached, the Schottley diode becomes conductive again and a spark is generated. Sparking occurs several times per second until the 22 transistors are turned on by the timer 20.
Therefore, the combustion lamp is blinking during this time.

The timer 19 continues to operate until combustion starts and the sensor a is sufficiently heated, but once the operation is completed, the transistor 21 oscillates based on the signal from the combustion detection circuit 20 alone. In the unlikely event that the combustion flame blows out, the solenoid valve 33 will stop and the voltage will no longer be obtained, and will close to prevent raw gas from flowing out, thereby preventing accidents due to gas leakage. Furthermore, if the transistor 21 is out of order, it will not oscillate, so the pulse transformer will not be energized and the solenoid valve will not open.

Effects of the Invention As described above, the present invention uses the voltage of over 100 V required for the igniter as a drive transformer for the solenoid valve, so a transformer for operating the igniter as in the past is unnecessary and is economical. It has excellent properties and is of high use value.

Also, when the solenoid valve is forcibly held, the combustion lamp blinks even without an oscillator, making it very easy to use.

[Brief explanation of the drawing]

Fig. 1 is an external perspective view of a conventional gas hot air fan heater, Fig. 2 is a block diagram of its combustion control circuit, Fig. 3 is a block diagram of a control circuit of a combustion appliance that is an embodiment of the present invention, and Fig. 4 The figure is the same control circuit diagram. 11...Igniter, 27...Combustion indicator lamp, 2
9...Pulse transformer, 33...Solenoid valve.

Claims (1)

[Scope of Claims] 1. A solenoid valve disposed in a fuel passage to control fuel supply, a pulse transformer that supplies current necessary for the solenoid valve by AC coupling, and a pulse transformer driven by a voltage on the primary side of the pulse transformer. A control device for a combustion appliance comprising an igniter. 2. A solenoid valve arranged in a fuel passage to control fuel supply, a pulse transformer that supplies current necessary for the solenoid valve by AC coupling, and an igniter driven by the voltage on the primary side of the pulse transformer. . A control device for a combustion appliance, comprising a light emitting display in a current path that supplies the igniter.