JPS6244171B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to a closed gas-fired boiler in which combustion waste gas from a burner is discharged by a fan and air is supplied to the burner. The present invention relates to a supply amount control device.

BACKGROUND OF THE INVENTION In improving the efficiency of variable output boilers,
In a blow-off burner boiler, whether it is a forced discharge type boiler or a forced introduction type boiler, a fan is used to change the amount of secondary air introduced depending on the amount of primary air introduced at each point in time. It is known to do so.

Air is supplied to the burner in a closed gas-fired boiler in large quantities to prevent incomplete combustion when the amount of gas burned is large, and when the amount of gas burned is small, the gas flame is extinguished by the supplied air. It is necessary to do it in just the right amount, by using a small amount so as not to waste it.

In known closed gas-fired boilers, the factors or parameters for adjusting or controlling the air supply required for gas combustion are the CO ₂ concentration in the waste gas, the smoke temperature, or the gas pressure of the burner.

However, there is no guarantee that these factors or parameters will vary accurately in response to the amount of gas burned.
Therefore, depending on these factors or parameters, there is no guarantee that the air required for gas combustion can be supplied in just the right amount.

Therefore, as a result of intensive research, the present inventor provided a first temperature detection means for directly detecting the heat output due to radiation and convection from the flame of the burner, and determined that the rotation speed of the fan was determined according to the output signal from the detection means. If you change the amount of air supplied to the burner and control the amount of air supplied to the burner,
It has been found that it is possible to improve the air supply to some extent.

The inventor also found that when the temperature of the water to be heated rises too much, the amount of gas thermal sintering decreases, and when the water temperature drops too much, the amount of gas sintering increases. Since it is desirable, a second temperature detection means for detecting the temperature of the water to be heated is provided, and the amount of gas supplied to the burner (in other words, the amount of gas burned) is controlled in accordance with the output signal from the second detection means. I thought it was a good idea.

A gas-fired boiler that was devised based on this idea while the present invention was being completed will first be explained. FIG. 1 shows such a boiler. The gas-fired boiler is installed in a closed housing 1, and combustion gas is exhausted by a fan 2 installed at the top of the boiler canopy. A thermal control detector or thermostatic probe 3, which is a first temperature detection means, is provided below the burner 4, and the detector 3 receives heat radiation from the flame of the burner 4 to activate a pair of switches 5 and 6. Control. A pair of resistors 12 and 13 are inserted in series in the wiring that supplies power to the motor of the fan 2 from the power source.

The gas flow rate supplied to the burner 4 is controlled by a pair of solenoid valves 7 and 9. The electromagnetic valves 7 and 9 are operated by contacts 8 and 8a in response to the amount of hot water or hot water demand detected by a thermostat 11, which is a second temperature detection means.

The operation of the above device is as follows.

Under continuous operating conditions, thermal control detector 3 controls switches 5 and 6 in response to the heat radiation of the burner flame. When the sensed temperature of the detector 3 corresponds to room temperature, both switches 5 and 6 are open and the motor of the fan 2 is connected to a pair of series resistors 1.
Since the current is supplied via 2 and 13, the fan 2 rotates at a low speed.

When the burner output is halved based on temperature detection by the thermostat 11, the solenoid valve 9 is held closed by the operation of the thermostat 11, and the solenoid valve 7 opens in response to the closing of the contact 8.
Gas is supplied to the burner 4 through. Thermal control detector 3 is then activated by heat radiation from the burner flame.
is heated, so that the detector activates switch 5. As a result, the only series resistance in the fan motor is resistor 13, so the motor rotates at an intermediate speed.

If thermostat 11 senses that the burner should be operated at full power, contact 8
a is closed, and the solenoid valve 9 is further opened. and,
By supplying a larger amount of gas, the amount of heat dissipated from the burner flame increases, and the heat control detector 3 causes the switch 6 to
is closed, and the fan motor has resistors 12 and 1
Since electric power is supplied without passing through any of the three, the fan 2 rotates at full speed.

Of course, in order to ensure the safety of the boiler, a control device (which may be a delayed type) for operating the fan appropriately may be installed to ensure sufficient smoke suction.

As a result of further research, the present inventor found that even when the temperature of the water to be heated rises too much and the amount of gas supplied to the burner is reduced due to a signal from the second temperature detection means, the amount of gas supplied to the burner is reduced due to the combustion of a large amount of gas. The above-mentioned first temperature detection means installed may not be able to respond immediately to the decrease in the amount of gas burned, and therefore the fan motor may continue to rotate at high speed, and excessive air may continue to be supplied to the burner. The rotation speed of the fan motor is also controlled according to the output signal from the second temperature detection means, that is, the output signal from the second temperature detection means is controlled regardless of the response delay of the first temperature detection means. They discovered that when the amount of gas supplied to the burner is reduced, the number of revolutions of the fan motor should be lowered, thereby reducing the amount of air supplied to the burner, and they were able to complete the present invention. Ivy.

SUMMARY OF THE INVENTION That is, the present invention provides an air supply control device for a closed gas-fired boiler in which combustion waste gas from a burner is discharged by a fan, and air is supplied to the burner accordingly. A first device that detects the heat output due to radiation and convection from the flame and emits a signal corresponding to the output.
temperature sensing means, first rotational speed control means for controlling the motor rotational speed of the fan according to the thermal output of the burner in response to the signal, and second rotational speed control means for sensing the temperature of the water to be heated. and a second rotational speed control means for controlling the motor rotational speed of the fan in response to the output of the second temperature detection means, and the first rotational speed control means is connected to a power supply. The second rotational speed control means is provided in a power supply circuit that supplies power to the motor of the fan, and the second rotational speed control means is provided in a power supply circuit on the power supply side by the first rotational speed control means, and the second rotational speed control means The present invention provides an air supply amount control device characterized in that the output of the means also controls the gas amount supply control means.

Examples of the temperature detection means used in the present invention include a thermostat or thermostatic probe, a resistor having a positive or negative temperature coefficient, an infrared cell, or an ultraviolet cell.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

According to one embodiment of the invention shown in FIG.
The rotational speed of the fan 20 is controlled by both a thermal control detector 28 (first temperature sensing means) and a hot water thermostat 23 (second temperature sensing means) corresponding to the heat radiation of the burner flame. . Contacts 21 and 2 operated by hot water thermostat 23
2, when the thermostat 23 senses that the burner should be operated at half power, the contact 21 closes and the solenoid valve 24 is opened, and when it is sensed that the burner should be operated at full power. Contact 2
2 is further closed, and solenoid valve 25 is also opened. In this way, the contacts 21 and 22 that open and close in response to signals and the solenoid valves 24 and 25 connected to these contacts constitute gas amount supply control means that operates in response to the output of the thermostat 23. ing. The motor rotational speed of fan 20 is controlled by switches 26 and 27 in response to thermal control detector 28.
controlled by. When the switch 26 is closed, a resistance is inserted in series, so the fan rotates at a low speed, and when the switch 27 is closed, the series resistance is removed, so the fan rotates at a high speed. In this way, the switch 26, which opens and closes according to the signal,
The resistor connected in series with 27 and switch 26 is
It constitutes a first rotational speed control means that controls the motor rotational speed of the fan 20 in response to the output of the thermal control detector 28. In this case, as can be seen from FIG. 2, even if the switch 27 is closed, if the contact 22 is opened (that is, the solenoid valve
5 is closed), a series resistor is inserted into the circuit of the fan 20, so the fan rotates at a low speed in response to a decrease in the amount of supplied gas. Furthermore, even if the switch 26 is closed, if the contact 21 is opened (that is, when the solenoid valve 24 is closed to stop the gas supply), the circuit of the fan 20 is opened and the fan stops. In other words, even if the burner is running at full power and the input to the detector 28 is at its maximum and the fan 20 is running at full speed,
If the thermostat 23 closes the solenoid valve 25 or 24 and the gas supply amount decreases, the fan 20
The rotational speed of is also reduced accordingly.

In this way, the contacts 21 and 22, which open and close according to signals, are provided in the power supply circuit on the power supply side of the first rotational speed control means including the above-mentioned series resistor, and The fan 20 constitutes a second rotational speed control means for controlling the motor rotational speed of the fan 20 in relation to the operation of the fan 20 .

FIG. 3 shows another example of the first temperature detection means and the first rotational speed control means. In FIG. 3, the gas-fired boiler is equipped with a fan 14 that can continuously vary the amount of waste gas discharged. The sensing means responsive to temperature changes in this case comprises a resistor 15 with a positive temperature coefficient, which resistor 15 is responsive to heat radiation from the flame of the burner 16. The resistor 15 is connected to an electrical circuit comprising another resistor 17, a control circuit 18 and a triax 19. The signal from the sensing means comprising the resistor 15 with the positive temperature coefficient is obtained as a voltage across the resistor 17, which voltage is applied to the control circuit 18. Control circuit 18
controls the power to the fan 14 by linearly adjusting the conduction angle at the trigger of the triax 19 in response to the voltage. In this manner, the triax 19 allows the rotational speed of the fan 14 to be continuously varied in accordance with the amount of heat released from the burner 16.

Various modifications may be made to the particular embodiments of the invention illustrated above without, of course, departing from the basic principles of the invention. A known integrated circuit may be used, and the rotational speed of the fan may be changed by frequency control as required.

Effects of the Invention According to the present invention, when the temperature of the water to be heated is lower than the set value, the amount of gas supplied to the burner (in other words, the gas heat The first rotational speed control means is controlled by the output signal from the first temperature detection means that detects the increase in the amount of gas burned, and the motor rotational speed of the fan is increased. The amount of air supplied to the burner is increased based on the actual increase in the amount of gas burned, not based solely on the water temperature detection, and as a result, the reliability of supply control of a sufficient amount of air is guaranteed. When the temperature of the water to be heated is higher than the set value, the gas supply is reduced by a signal from the second temperature detection means according to the temperature of the water to be heated, but in this case, a decrease in the actual burner heat output is sensed. Even if there is a delay in the response of the first temperature detection means caused by Since it is installed in the power supply circuit on the power supply side, the fan motor speed is
Based on the electric power control operation of the second rotational speed control means, the amount of gas supplied to the burner, in other words, is controlled in response to the amount of gas burned, and the air required for combustion is supplied in substantially the same amount.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a schematic diagram of one embodiment, FIG. 2 is a schematic diagram of main parts of another embodiment, and FIG. 3 is a schematic diagram of another embodiment. It is a schematic diagram of an example. 1... sealed housing, 2... fan, 3...
Thermal control detector, 4... Burner, 5, 6... Switch, 7, 9... Solenoid valve, 8, 8a... Contact, 1
1... Thermostat, 12, 13... Resistor, 1
4...Fan, 15...Resistor, 16...Burner, 17...Resistor, 18...Control circuit, 19...
Triack, 20... Juan, 21, 22...
Contact, 23... Thermostat, 24, 25...
Solenoid valve, 26, 27... switch, 28... thermal control detector.

Claims (1)

[Claims] 1 An air supply amount control device for a closed gas-fired boiler in which combustion waste gas from a burner is discharged by a fan and air is supplied to the burner accordingly, a first temperature detection means for detecting heat output due to convection and emitting a signal according to the output; and a first temperature detection means for controlling the motor rotation speed of the fan according to the heat output of the burner in response to the signal. a first rotation speed control means, a second temperature detection means for detecting the temperature of the water to be heated, and a second temperature detection means for controlling the motor rotation speed of the fan in response to the output of the second temperature detection means. 2 rotational speed control means, the first rotational speed control means is provided in a power supply circuit that supplies power to the motor of the fan from a power source, and the second rotational speed control means is configured to control the first rotational speed. An air supply amount control device, which is provided in a power supply circuit on the power supply side of the speed control means, and wherein the output of the second temperature detection means also controls the gas amount supply control means.