JPS63694B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a combustion control device that reduces noise at the time of ignition by slowly igniting the main burner. Regardless of the situation, the aim is to reduce the ignition noise by always igniting with a small amount of gas during initial ignition and during ON-OFF ignition.

Conventionally, for example, in the case of a combustion control device for a water heater, energization to a solenoid valve is controlled by a signal from a temperature sensing element, and when hot water is being supplied, the temperature sensing element outputs a large gas volume signal to energize the solenoid valve. The ignition noise due to the large amount of gas was loud and harsh, which was considered a problem.

The present invention eliminates these conventional drawbacks, and embodiments thereof will be described below with reference to the accompanying drawings.

In Fig. 1, 1 is a DC power source consisting of a power transformer and a rectifier circuit, 2 is a switch that operates by detecting combustion of the pilot flame, 3 is a temperature sensing element (thermistor) that detects the temperature of hot water, and 4 is a current flowing current. 5 is a proportional control circuit with an ON-OFF function configured to control the current flowing to the solenoid valve 4 based on the signal from the temperature sensing element 3; 6; is a switching circuit that detects the ON signal of temperature sensing element 3 with a voltage comparator, 7 is a timer circuit composed of a voltage comparator, 8 is a slow ignition circuit having an ideal diode circuit using an operational amplifier, and 9 is a slow ignition circuit. 10 is a current control circuit for the pseudo large ignition signal circuit 9, 11 is a constant voltage diode, 12 is a resistor, and 13 is a constant voltage diode.

In the proportional control circuit 5 with ON-OFF function, 1
4 is a diode for preventing reverse voltage of solenoid valve 4, 15
is a resistor, 16 is a resistor, 17 and 18 are diodes,
19 is a transistor, 20, 21, 22, 23 are resistors, 24 is a transistor, 25, 26 are resistors,
27 is a transistor, 28 is a resistor, 29, 30 are transistors, 31, 32, 33 are resistors, 34 is a capacitor, 35 is a transistor, 36 is a resistor,
37 is a transistor, 38 is a resistor, 39 is a feedback resistor, and 69 is a diode.

40 is a first voltage comparator using an operational amplifier;
Power terminals 40a, 40b, input terminals 40c, 40
d, has an output terminal 40e. Above power terminal 40
a and 40b are connected to both ends of the constant voltage diode 13.

41, 42, 43, 44, 45, 46 are resistances,
47 is a capacitor for noise absorption. 48 is a transistor, which constitutes the switching circuit 6.

49 is a second voltage comparator, and power supply terminals 49a, 4
9b, input terminals 49c, 49d, output terminal 49e
have. Power supply terminals 49a and 49b are connected to both ends of the constant voltage diode 13.

50, 51, 52, 53, and 54 are resistors, and 55 is a timer capacitor, which constitute a timer circuit 7.

56 is an operational amplifier, and power terminals 56a, 56
b, has input terminals 56c, 56d, and an output terminal 56e. A diode 57 constitutes an ideal diode by being connected between the input terminal 56c and the output terminal 56e of the operational amplifier 56, and constitutes the slow ignition circuit 8 together with resistors 58 and 59.

60 is a resistor, 61 is a diode, 62 is a capacitor, 63 is a diode, 64 is a resistor, 65, 6
6 is a diode, which constitutes a pseudo large ignition signal circuit 9.

67 is a third voltage comparator, and power terminals 67a, 6
7b, input terminals 67c, 67d, output terminal 67e
have. Reference numeral 68 indicates a resistor, which serves as a pseudo large ignition signal circuit 9 that operates in reverse to the second voltage comparator 49.
The energization control circuit 10 is configured.

Next, the operation will be explained.

As a DC power source 1 and a power source, when pilot flame combustion is detected by some means by operating the gas stove, switch 2 is turned on and power is supplied.
Current is applied to the constant voltage diode 11 through the resistor 15, and constant voltage power is supplied to both ends of the diode 11.

To explain the operation of the proportional control circuit 5 with ON-OFF function, a bridge circuit is formed consisting of a resistor 16, diodes 17 and 18, a temperature sensing element 3, and resistors 21, 22, and 23. The transistor 19 is turned on and off by changing the resistance value of a certain temperature sensing element 3. Therefore, as the resistance value of the temperature sensing element 3 increases to the set point at which the transistor 19 turns on, the transistor 19 turns on.
turns on, and transistors 24 and 27 turn on.
Turn off.

Further, the current flowing through the transistor 19 increases through the resistor 20 depending on the resistance value of the temperature sensing element 3, and the current amplified by the resistor 20 flows to the resistors 22 and 23.

Transistors 29 and 30 provided in the bridge circuit of resistors 21, 22, 23 and 32, 33 constitute a differential amplifier, and when the voltage across resistors 22 and 23 increases, transistor 29 is turned off.
begins to At the same time, the transistor 30 turns on and the amount of current flowing through the resistor 31 increases. transistor 3
When the voltage of V _BE of 7 and 35 is exceeded, transistor 3
5 and 37 are turned on, the solenoid valve 4 is energized, the return resistor 39 detects the current energized to the solenoid valve 4, the fluctuation in the voltage across the resistor 33 is detected, and the resistor 31 is energized through the transistor 30. Control the current.
Therefore, the current flowing to the resistor 31 is controlled in proportion to the rise and fall of the resistance value of the temperature sensing element 3, and the current flowing through the transistor 3 is controlled.
5 and 37 to control the current to the solenoid valve 4.

Furthermore, when the temperature of the water is sensed and the resistance value of the temperature sensing element 3 decreases, causing the bridge to become unbalanced, the transistor 19 is turned off, and at the same time, the transistors 24 and 27 are turned on, and the base voltage of the transistor 35 is applied through the diode 69. In order to suppress the voltage to about 0.7V,
Transistors 35 and 37 are turned off, and solenoid valve 4 is not energized and closed. When the transistor 27 turns off by sensing the water temperature and changing the resistance value of the temperature sensing element 3, the transistor 35 turns off the resistance value of the temperature sensing element 3.
The amount of current supplied to the solenoid valve 4 is controlled in proportion to the voltage across the temperature sensing element 3, that is, the voltage across the temperature sensing element 3. The amount of gas is proportionally controlled by the applied current.

FIG. 2 shows the operation of the switching circuit 6. Here, the input terminal 40c of the first voltage comparator 40 of the switching circuit 6 uses the voltage across the resistor 31 as the input voltage so as to detect whether the solenoid valve 4 is in the ON or OFF state based on the resistance value of the temperature sensing element 3. are connected like this. One input terminal 40d uses the constant voltage diode 13 as a power source, and has a reference voltage V _40d set by resistors 41, 42, and 43.

Now, if the thermosensor 3 senses that the water temperature is high and turns off the solenoid valve 4, the transistor 27 is on, so the input terminal 40c is equal to the forward voltage drop of the diode 69. (approximately 0.7V) is input. At that time V _40d is approximately Since the input voltage of V _40c is lower than the reference voltage V _40d , the output terminal 40e is in the H state, the transistor 48 is off, and the switching circuit 6 is off.

However, when hot water is supplied, when the hot water faucet is opened, the temperature sensing element 3 senses that the temperature is low and its resistance value increases, so that at the same time as the transistor 19 is turned on, the transistors 24 and 27 are turned off.

Then, the voltage across the resistor 31 becomes V _40c , exceeding the reference voltage of V _40d , and the output terminal 40e becomes L.
state, and the transistor 48 is turned on. This state is shown in FIG.

Next, FIG. 3 shows the operation of the timer circuit 7. In the timer circuit 7, the input terminal 49d is connected to a resistor 50,
With respect to the reference voltage V _49d set by 51 and 52, the input terminal 49c becomes the output terminal when the transistor 48 is off, that is, when the temperature sensing element 3 is off, the voltage across the resistor 54 is at 0 potential. 49e is in the H state because the input terminal 49e is lower than V _49d , and at the same time, the output terminal 67e of the third voltage comparator 67 is in the L state because 67c is higher than the reference voltage of the input terminal 67d, and a pseudo large ignition signal is generated. Capacitor 62 of circuit 9 is not charged. On the other hand, at the same time, the ideal diode circuit using the operational amplifier 56 is inoperative, and the slow ignition circuit 8 is inoperative.

However, since the transistor 48 is turned on, a charging current flows to the timer capacitor 55 of the timer circuit 7 at the same time as the transistor 48 is turned on. The voltage V _49c at the input terminal 49c momentarily rises to the power supply voltage and exceeds the reference voltage V _49d , so the output terminal 49e goes into the L state (FIG. 3 shows this operating waveform). When the output terminal 49e becomes L, the output terminal 6
7e is in the H state, and a resistor 60 and diodes 61, 6 are connected to the capacitor 62 of the pseudo large ignition signal circuit 9.
It is charged through 3.

At the same time, a resistor 59 is connected in parallel with the temperature sensing element 3 through the diode 57 of the slow ignition circuit 8 having an ideal diode circuit, and the proportional control circuit 5 operates according to the resistance value of the temperature sensing element 3 to supply current to the solenoid valve 4. Rather than flowing, a current set by the resistance value of the temperature sensing element 3 and the parallel resistance of the resistor 59 is applied to the solenoid valve 4.

That is, the slow ignition circuit 8 is the second one of the timer circuit 7.
When the output terminal 49e of the voltage comparator 49 is in the L state,
V _56d is the reference voltage set by V _ZD11 × R ₅₉ /R ₅₈ + R ₅₉ , and the reference voltage V _56d + forward voltage drop of diode 57 (approximately 0.7 V) is applied in parallel with temperature sensing element 3. This is applied as a slow ignition current to the solenoid valve 4.

Charging of the timer capacitor 55 has started.
When V _49c falls below V _49d , output terminal 49e goes high.
In this state, the slow ignition circuit 8 becomes inoperative, and the apparent parallel resistance 59 is removed, so that the current set by the resistance value of the temperature sensing element 3 flows to the solenoid valve 4.

On the other hand, since the output terminal 49e becomes H (high) state, the capacitor 6 of the pseudo large ignition signal circuit 9
The charge stored in 2 is transferred to resistor 64 and diode 65.
The electric charge of the capacitor 62 is superimposed on the temperature sensing element 3 as a pseudo large ignition signal, and the electromagnetic valve 4 is energized.

As the electric charge stored in the capacitor 62 is applied to the temperature sensing element 3, the voltage V _th across the temperature sensing element 3 increases as shown in FIG. A large current follows the signal of element 3, as shown in the diagram a.

Furthermore, the figures b and c show the state in which the electric charge of the capacitor 62 is discharged to the temperature sensing element 3 due to the temperature of the temperature sensing element 3 itself, and shows that it varies depending on the resistance value of the temperature sensing element. .

In Fig. 5, the proportional control circuit 5 operates in response to the signal of the voltage V _th across the temperature sensing element 3, and energization is controlled to the solenoid valve 4, so the amount of gas corresponding to each is illustrated. It is something.

Therefore, during the timer operation time (slow ignition time) of the timer circuit 7, the set slow ignition current is passed through the solenoid valve 4, and after the timer operation time (slow ignition time), the current is passed according to the signal of the temperature sensing element. Electricity is supplied to the electromagnetic valve 4, so that the ignition does not occur with a large amount of gas at the time of ignition, but is ignited with a small amount of gas using a slow ignition signal.

In addition, when ON-OFF control is performed by sensing the hot water temperature of the temperature-sensing element 3, for example when using heating, when turning the solenoid valve 4 ON-OFF by sensing the hot water temperature of the temperature-sensing element 3, the temperature-sensing element 3 In response to the ON signal, the pseudo large ignition signal circuit 9 operates so that the electric charge of the capacitor 62 is pseudo-superimposed on the temperature sensing element 3 along with the slow ignition operation, and a large current is pseudo-energized to the solenoid valve 4. It operates to measure the certainty of ignition by emitting a large amount of gas.

The above operations are shown in FIGS. 2 to 5. That is, FIG. 2 is an explanatory diagram of the operation of the first voltage comparator 40 of the switching circuit 6, FIG. 3 is an explanatory diagram of the operation of the second voltage comparator 49 of the timer circuit 9, and FIG. 4 is a diagram of the characteristics of the temperature sensing element 3. In the explanatory diagram, a indicates a large signal, b indicates a small signal, c indicates an on/off signal, and d indicates a time without slow ignition. Figure 5 is an explanatory diagram of the operation of the solenoid valve, a,
b, c, d correspond to FIG. 4.

As described above, according to the present invention, the following excellent effects can be expected.

When the temperature sensing element signal outputs a large amount of gas signal, such as when hot water is being used, the slow ignition circuit operates to supply a slow ignition current to the solenoid valve.
Since it ignites, the ignition noise can be reduced compared to conventional methods.

In order to control the water temperature to a high temperature during heating operation, etc., the current flowing to the solenoid valve is reduced based on the detection signal of the temperature sensing element, and even if a small amount of gas is burned, the water temperature rises too much and the solenoid valve is turned on. ，When turning off,
Since the signal from the temperature-sensing element itself causes ignition of a small amount of gas, ignition can be performed with a large amount of gas using a pseudo-large ignition signal after slow ignition, and the reliability of ignition can be measured.

Since the current applied to the solenoid valve is controlled for slow ignition, it can be controlled by the constants (resistance values) of resistors 58 and 59 of the slow ignition circuit 8 so that slow ignition can be achieved with any amount of gas. , complex configurations such as slow ignition burners are not required.

It is cheaper than mechanical components (such as slow ignition burners).

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2 is an explanatory diagram of the operation of the first voltage comparator, Fig. 3 is an explanatory diagram of the operation of the second voltage comparator, and Fig. 4 is an illustration of the operation of the temperature sensing element. The voltage characteristic diagram, FIG. 5, is an explanatory diagram of the operation of the solenoid valve. 3... Temperature sensing element, 4... Solenoid valve, 5... Proportional control circuit, 6... Switching circuit having first voltage comparator 40, 7... Timer circuit having second voltage comparator 49, 8... Using operational amplifier 56. A slow ignition circuit with an ideal diode circuit.

Claims (1)

[Claims] 1. A temperature sensing element that senses the water temperature, a proportional control circuit with an ON-OFF function that proportionally controls the amount of gas by controlling the amount of energization of a solenoid valve based on the signal from this temperature sensing element, and an ON signal for the proportional control circuit. a switching circuit having a first voltage comparator for detecting the switching circuit, a timer circuit having a second voltage comparator operated by the ON signal of the switching circuit, a slow ignition circuit having an ideal diode circuit using an operational amplifier, and a resistor. and a pseudo large ignition signal circuit consisting of a capacitor, and when the solenoid valve is opened by the signal of the temperature sensing element, a slow ignition signal is generated by the signal of the slow ignition circuit during the timer operation time of the timer circuit, and , after the timer operation ends, the charge stored in the capacitor of the pseudo large ignition signal circuit is discharged, a pseudo large ignition signal is superimposed on the signal of the temperature sensing element, and the electromagnetic valve is energized. Combustion control device.