JPS5827251Y2 - Combustion control device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a combustion control device that uses an ignition discharge electrode for flame detection to control ignition operation.

As a conventional example of this type of device, one described in Japanese Patent Application Laid-Open No. 51-46438 is known.

This converts DC power to AC using an inverter circuit,
This output charges the ignition capacitor, and when Nagai is formed, the switching element is made conductive to discharge this capacitor, generating a high voltage at the discharge electrode of the ignition transformer, igniting the burner, and discharging the flame detection when the flame is formed. This is done by establishing electrical continuity between the electrode and the counter electrode.

By conducting these two electrodes, the trigger capacitor of the switching element is shorted and the switching element is made non-conductive, thereby stopping the ignition operation.

However, with such a conventional configuration, soot from the burner flame may adhere between the electrodes at small intervals, causing an erroneous conduction state, or if the gas type is 13A, the flame may cause a conduction state due to high resistance. As a result, the bypass to the capacitor cannot be completed during flame formation, and the ignition means may continue to operate even though ignition has been completed.

The present invention has been devised in view of this point, and an example of its actual winding will be explained below with reference to the drawings.

1 is a dry battery, 2 is a power switch, and 3 is an inverter circuit consisting of an oscillation transistor 4 and an oscillation transformer 5.

6 is an ignition circuit connected to the secondary side of the oscillation transformer 5;
A silicon controlled rectifier (SC
R) 8 and the primary side of an ignition transformer 9 are separately connected in series, an ignition capacitor 10 is further connected in series to the primary side of the transformer 9, and a Zener input directly from the oscillation transformer 5 is connected to the gate of 5CR8. A trigger device 13 consisting of a diode 11 and a capacitor 12 is connected, and the secondary side of the ignition transformer 9 is connected to an oscillation transformer 5 via the capacitor.
A discharge electrode 14 with a burner (not shown) as a counter electrode is connected to the secondary side of the discharge electrode.

Reference numeral 15 denotes a detection circuit, which inputs an input from the midpoint of the connection between the resistor connected in parallel to the discharge pole 14 and the detection capacitor 16, and sends it through a pair of protective Zener diodes 17 and 17 and a filter 18 to generate an electric field effect. type transistor (hereinafter referred to as F
(referred to as ET) 19.

Reference numeral 20 denotes a drive circuit that keeps the fuel supply valve (not shown) open in response to the output signal of the FET 19 and also stops the ignition circuit 6 at that time. have,
The dry battery 1 is connected to the collector of this transistor 21, and an operating coil 22 for keeping the fuel supply valve open is connected to the collector of the transistor 21, and furthermore, the emitter is connected in parallel to the trigger device 13 and is connected to the trigger device 13 when conductive. The base of an NPN control transistor 230 which bypasses the supply current is connected.

Next, the operation will be described. First, the fuel supply valve is manually opened, and the power switch 2 is closed in conjunction with this.

Then, alternating current is output to the secondary side of the oscillation transformer 5,
Thereby, the ignition capacitor 1 is connected via the diode 7.
0 charging begins, and the FET 19 receives a signal attenuated to approximately zero potential by the filter 18 and becomes conductive. The driving transistor 21 and the control transistor 23 are rendered non-conductive, and the actuating coil 22 is also not operated.

Thus, the trigger device 13 conducts 5CR8 at an appropriate cycle, discharges the capacitor 10, induces a high voltage on the secondary side of the ignition transformer 9, and ignites the burner by the spark generated at the discharge pole 14. .

When a flame is formed in the burner, a flame rectification effect occurs in the discharge poles 14, whereby the positive half-wave of the output of the oscillation transformer 5 is bypassed by the discharge pole 14, and the negative half-wave is bypassed by the discharge pole 14. is charged by the detection capacitor 16 of the detection circuit 15, and the FET
19 is given a deep negative signal to make it non-conductive.

Therefore, the drive transistor 21 and the control transistor 23 are rendered conductive, activating the actuation coil 22 to keep the fuel supply valve open, and bypassing the input to trigger device #13 to stop the device from operating. , thereby stopping the operation of the ignition circuit 6.

Here, if the discharge electrode 14 is short-circuited due to soot, there is only a high resistance there and no rectification effect occurs, so the F
Since the ET 19 continues to be conductive, the actuating coil 22 will not erroneously maintain the valve open.

Also, when a flame such as 13A burns a gas that produces high resistance, the rectifying effect of the flame occurs even if there is high resistance, so FE
T19 can perform normal operation.

As described above, the combustion control device according to the present invention is equipped with a DC power supply, an inverter circuit, an ignition circuit, a detection circuit, and a drive circuit, and the ignition circuit and detection circuit are connected to the inverter circuit, and a detection capacitor is connected to the ignition discharge poles. When connected in parallel, when a flame is formed on the electrodes, the detection capacitor is charged due to the rectification effect, which activates the detection circuit, which prevents soot from adhering to the electrodes and producing a false signal of flame formation. Even if this occurs, the detection circuit will not malfunction.

Further, even if the flame is replaced with a fuel that produces a high resistance value, the detection circuit can operate normally, and even if, for example, calorie conversion of gas is performed, it can be sufficiently coped with.

Furthermore, since the ignition circuit is stopped by flame formation, power consumption can be reduced even if the DC power source is a household dry cell battery, and the life of the device can be extended.

[Brief explanation of the drawing]

The figure is an electrical circuit diagram of a combustion control device according to the present invention. 1... Dry battery, 3... Inverter circuit, 6... Ignition circuit, 8... SCR, 9
...Ignition transformer, 13...Trigger device, 14...Discharge pole, 15...Detection circuit, 16...Detection capacitor , 19...
...FET, 20... Drive circuit, 21...
. . . Drive transistor, 23 . . . Control transistor.

Claims (1)

[Scope of utility model registration request] A DC power supply, an inverter circuit that converts it to AC,
An ignition circuit is connected to the inverter circuit and includes an ignition transformer having discharge poles for igniting the burner and detecting the flame formed, and a switching element for controlling the transformer; A detection circuit consisting of a detection capacitor connected in parallel to the pole and a detection output element that generates a detection output when this capacitor is charged by the rectifying action of the flame, and a detection output of the switching element connected to the DC power supply. A combustion control device that includes a drive circuit consisting of a control element that stops the operation of a trigger device.