JPS6262256B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a combustion control device that gradually increases the amount of gas according to the temperature of hot water after ignition.

Generally, in a gas combustion device, it is desirable that the outlet temperature of the hot water reaches a desired temperature as quickly as possible after ignition. For this reason, if combustion is performed at full power immediately after ignition, the desired temperature will be reached in a short time, but the thermal response of the heat exchanger is slow, so even if combustion is suppressed after the desired temperature is reached, the hot water temperature will rise for a while. This is not preferable because it will lead to overheating. To prevent this, it is possible to gradually reduce the amount of combustion, but if it is re-ignited within a short time after combustion ends, the disadvantage is that even if you gradually reduce the amount of combustion from full output due to residual heat, it will not be in time, resulting in overheating. .

The present invention relates to a combustion control device that improves the above-mentioned drawbacks and increases the temperature of tapped water in a relatively short period of time.

FIG. 1 is a schematic diagram showing one embodiment of the present invention, and FIG. 2 is a diagram showing details of the main part of FIG. 1.

In the figure, 1 is the main burner, a pilot burner 2 is installed next to it, and an electromagnetic proportional valve 3.
Gas is supplied via. Gas is supplied to the electromagnetic proportional valve 3 and the pilot burner 2 from a main valve 4, and the main valve 4 is opened and closed by a knob 5. Picker 5
When operated, the water valve 6 is also opened and water flows into the heat exchanger 7. At the same time, the ignition circuit 8 is activated and the pilot burner 2 is ignited. When the flame is ignited, the flame is detected by the flame detection circuit 9, and the valve drive circuit 11 is operated by the output circuit 10 which gradually increases the output based on the output of the flame detection circuit 9. 12 is a thermistor that works as a sensor.

The output circuit 10 includes a suppression circuit 10A, a signal circuit 10B, a switching circuit 10C, and a non-inverting amplifier circuit 10D.
The suppression circuit 10A includes an operational amplifier OP1 that functions as a differentiating circuit, a transistor Tr1, resistors R1, R2, and a capacitor C1, and the signal circuit 10B includes transistors Tr2, Tr3, and a FET.
It has T1, resistor R3, and capacitor C2. The switching circuit 10C has an operational amplifier OP2 functioning as a comparator, a flip-flop FF, and FET gates G1 and G2, and the non-inverting amplifier circuit 10D has an operational amplifier OP3 and resistors R4 to R10. Further, the valve drive circuit 11 is composed of an operational amplifier OP4, a transistor Tr4, and a resistor R11. R12 is a resistor.

Next, the operation will be explained. Before operating the knob 5, the main valve 4 and water valve 6 are closed, and the ignition circuit 8 is also inactive. Operate knob 5 to open main valve 4 and water valve 6.
is opened to supply gas to the pilot burner 2 and to flow water to the heat exchanger 7. At the same time, the ignition circuit 8 is driven to generate a spark and ignite the pilot burner 2.

When ignition is detected by the flame detection circuit 9, the output circuit 10 is activated and the ignition circuit 8 is soon deactivated. The signal circuit 1 is activated by the output of the flame detection circuit 9.
The transistor Tr2 of 0B becomes conductive, the transistor Tr3 becomes operational, and while the transistor Tr1 of the suppression circuit 10A is off, the transistor Tr3 becomes conductive, and the capacitor C2 is charged via the resistor R3. Therefore, FET T1 gradually becomes conductive due to the time constant of resistor R3 and capacitor C2, and if FET gate G1 of switching circuit 10C is in a conductive state, an output gradually rises to the positive input side of non-inverting amplifier circuit 10D. is given, and in response to this output, the non-inverting amplifier circuit 10D outputs a rising signal to the valve drive circuit 11.

Since the set S signal is applied to the flip-flop FF of the switching circuit 10C when the knob 5 is operated, the FET gate G1 becomes conductive and the FET gate G becomes conductive.
2 is non-conductive. After a while after ignition, the temperature of the hot water rises and the terminal voltage of the thermistor 12 drops below the set voltage determined by the resistors R4, R5, and R6, an output from the operational amplifier OP2 is generated, the flip-flop FF is reset, and the FET gate G1 is non-conductive, FET gate G2 is conductive, and thermistor 1
The output of 2 is given to the non-inverting amplifier circuit 10D.
Therefore, after the water reaches a predetermined temperature determined by the variable resistor R4, the gas amount is adjusted according to the water temperature.

The suppression circuit 10A is normally in an inactive state,
If the resistance value of the thermistor 12 suddenly changes due to a sudden temperature rise in the process of reaching a predetermined temperature, the change is detected and the transistor Tr3 of the signal circuit 10B is activated.
Works to turn it off. In other words, the change in the terminal voltage of the thermistor 12 is detected by a differential circuit, and the output turns on the transistor Tr1, which in turn turns the transistor Tr1 on.
Turn off Tr3. In this state, capacitor C
2 is not charged, and the non-inverting amplifier circuit 10D, which had been gradually increasing its output, temporarily maintains the same level. Therefore, when the water temperature rises rapidly immediately after ignition, the electromagnetic proportional valve 3 is kept in a state where the amount of gas is small. Then, every time the temperature rises rapidly thereafter, the suppression circuit 10A operates, and when the water temperature reaches a predetermined temperature, FET gates G1 and G2 are switched in that state, so the water temperature will not rise to an overheating state. do not have.

As described above, the present invention includes a gas burner, an electromagnetic proportional valve that controls the amount of gas to the gas burner, an ignition circuit for the gas burner, a signal circuit that detects ignition and gradually increases the output, and a heat exchanger. A sensor that detects the hot water temperature of the heat exchanger, a switching circuit that outputs the output of a signal circuit when igniting, and switches to output the output of the sensor when the hot water temperature reaches a predetermined temperature, and An amplifier circuit that outputs the difference between the output of the sensor or the output of the signal circuit and the set temperature, a valve drive circuit that drives the proportional valve according to the output of this amplifier circuit, and a signal circuit that outputs the difference between the output of the sensor or the output of the signal circuit and the set temperature. When the gas burner is ignited, the combustion amount of the gas burner is gradually increased by the startup output of the signal circuit, and if there is a large temperature change in the outlet temperature during this increase, By suppressing the increase in the amount of combustion using the suppression circuit, the hot water temperature can be raised to near the set temperature in a relatively short period of time while reducing overshoot of the hot water temperature.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing one embodiment of the present invention, and FIG.
The figure is a detailed view of the main parts. In the figure, 1 is a main burner, 3 is an electromagnetic proportional valve, 8 is an ignition circuit, 10 is an output circuit, 10A is a suppression circuit, and 11 is a valve drive circuit.

Claims (1)

[Claims] 1. A gas burner, an electromagnetic proportional valve that controls the amount of gas to the gas burner, and an ignition circuit for the gas burner.
A signal circuit that detects ignition and gradually increases the output, a heat exchanger, a sensor that detects the hot water temperature of the heat exchanger, and a sensor that outputs the output of the signal circuit when ignition occurs and when the hot water temperature reaches a predetermined temperature. a switching circuit that switches to output an output of A combustion control device comprising: a valve drive circuit that drives the proportional valve; and a suppression circuit that stops starting the signal circuit according to a differential value of the sensor output.