JPH11108346A - Combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop a combustor where appropriate blast is performed even in case that there is no burden of adjusting a gas proportional control valve or that the primary pressure of gas drops. SOLUTION: This combustor is provided with a pressure sensor 16 on the secondary side of a proportional control valve 15, so as to measure the pressure difference between the pressure within a burner case 2 and the secondary side of the proportional control valve 15. A gas proportional control valve is controlled, based on the pressure difference between the secondary side of the proportional control valve 15 and the burner case 2. Moreover, the fan is controlled likewise, based on the pressure difference.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion device used for a water heater or the like.

In recent years, water heaters have become widespread even in ordinary households. Many of the combustion devices used in domestic water heaters have a function of changing the combustion amount of fuel such as gas in accordance with the temperature and amount of hot water. As a measure for changing the combustion amount, a gas proportional control valve is generally used. The gas proportional control valve changes its opening depending on the magnitude of the signal current.

In a combustion device used for a water heater or the like,
Many have a fan to supply air to the burner. Further, in this type of combustion device, since it is necessary to supply an appropriate amount of air in accordance with the amount of combustion, a configuration is adopted in which the number of revolutions of the fan motor is increased or decreased in accordance with the amount of fuel supplied. That is, the relationship between the number of rotations of the fan motor, the drive current or voltage, and the amount of air is stored in advance, and the number of rotations and the drive current or voltage of the fan motor are controlled so that the amount of air corresponds to the amount of fuel supplied. . Here, in the conventional combustion device, the fuel supply amount is determined based on the opening degree of the gas proportional control valve, and the rotation speed of the fan motor is changed.

[0004]

As described above, the gas proportional control valve changes its opening according to the signal current as described above, and the gas actually supplied from the gas proportional control valve is the primary pressure of the gas. And so on. Therefore, at the installation site of the combustion device, it is necessary to adjust the gas proportional control valve so that the supplied gas amount becomes a predetermined amount, which is troublesome. Also, when replacing the gas proportional control valve, it is necessary to readjust the adjustment again, and there is a problem that the burden on the maintenance person is large. Adjustment of the gas proportional control valve is generally performed by operating a volume. However, when a general consumer mistakenly operates the volume, the gas proportional control valve may not function normally.

[0005] As another problem, there is a concern that the air-fuel ratio may change in a combustion device configured to change the rotation speed of the fan motor based on the opening of the gas proportional control valve. That is, as described above, in the conventional combustion device,
The fuel supply amount is determined based on the opening degree of the gas proportional control valve, and the rotation speed of the fan motor is changed. The prior art measures assume that the same amount of gas is always supplied as long as the opening of the gas proportional control valve is the same. However, if the primary pressure of the gas drops for some reason, a situation occurs in which the gas supplied from the gas proportional control valve is less than a predetermined amount. Then, in the configuration of the related art, even when the gas supply amount is small, the rotation speed of the fan motor is the same as when the gas amount is normal. Therefore, the conventional combustion device has a problem that when the primary pressure of the gas decreases, the air becomes excessive.

Accordingly, the present invention focuses on the above-mentioned problems of the prior art, and there is no burden to adjust the gas proportional control valve, and even if the primary pressure of the gas is reduced, proper ventilation is performed. The purpose is to develop a combustion device that can be used.

[0007]

According to the first aspect of the present invention, there is provided a burner, a control valve provided in a fuel supply path for supplying fuel to the burner, and an opening of the control valve. A combustion apparatus having valve control means for adjusting the degree of pressure, wherein a pressure sensor is provided on the secondary side of the control valve, and the opening of the control valve is adjusted in accordance with a signal from the pressure sensor. It is.

[0008] The amount of fuel supplied from the control valve to the burner is determined by the pressure on the secondary side of the control valve. In the combustion device of the present invention, since the pressure sensor is provided on the secondary side of the control valve, the supply amount of the fuel can be known from the signal of the pressure sensor. Then, in the combustion device of the present invention, the opening of the control valve is adjusted according to the signal of the pressure sensor, and a desired combustion amount can be obtained.

According to a second aspect of the present invention, there is provided a burner, a control valve provided in a fuel supply path for supplying fuel to the burner, and a fuel control for adjusting an opening of the control valve. Means, a fan for supplying air to the burner, and a combustion device having rotation speed control means for controlling the rotation speed of the fan, wherein the rotation speed of the fan is increased or decreased according to the amount of combustion,
A combustion device, wherein a pressure sensor is provided on a secondary side of a control valve, and a rotation speed of a fan is adjusted according to a signal of the pressure sensor.

In the combustion apparatus according to the present invention, the control valve adjusts the rotation speed of the fan based on the pressure on the secondary side. for that reason,
The amount of fuel supplied to the burner can be grasped more accurately, and the fan can be rotated at an appropriate speed.

According to a third aspect of the present invention, the burner is disposed in a burner case, and the pressure sensor detects a pressure difference between the burner case and a secondary side of the control valve. The combustion device according to claim 1 or 2, wherein:

[0012] The amount of fuel exiting the burner is a function of the pressure difference across the burner. The combustion device of the present invention detects the pressure difference between the burner case and the secondary side of the control valve by the pressure sensor, so that the pressure difference between the inside and outside of the burner can be accurately detected, and the amount of fuel can be grasped more accurately. can do.

According to a fourth aspect of the present invention, which is a further development of the above-mentioned invention, the control valve is controlled by a control including an integral control. Device.

In the combustion device of the present invention, the control valve is controlled proportionally and integratedly. Therefore, the fuel supply is
Reach the target value quickly.

According to a fifth aspect of the present invention, which is a further development of the above-described invention, the actual calorific value of the burner, the signal of the pressure sensor expected when the calorific value is generated, and
2. The apparatus according to claim 1, further comprising a correction unit configured to compare a signal of the pressure sensor with a signal of an actual pressure sensor and correct the signal of the pressure sensor.
A combustion device according to any one of claims 1 to 4.

In the present invention, since the signal of the pressure sensor is corrected based on the actual amount of generated heat, errors occurring at each stage can be corrected.

[0017]

Embodiments of the present invention will be described below. FIG. 1 is a block diagram of a combustion device according to an embodiment of the present invention. FIG. 2 is a specific circuit diagram of the valve control means shown in FIG. FIG. 3 is a block diagram of an embodiment of the present invention. FIG. 4 is a block diagram of another embodiment of the present invention. FIG. 5 is a sectional view showing a pressure sensor mounting portion according to another embodiment of the present invention. FIG. 6 is a specific circuit diagram of valve control means according to another embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a combustion apparatus according to an embodiment of the present invention. The combustion device 1 of this embodiment forms a part of a water heater, and has a mechanical configuration as follows. That is, the combustion device 1 has a burner case 2, and two burners 3 and 4 and a heat exchanger 5 are built in the burner case 2. A fan 7 is attached to the burner case 2, and forced air is blown into the burner case 2 by rotation of the fan motor 8.

The burners 3 and 4 selectively burn both or only one of the burners according to the amount of combustion, and solenoid valves 10 and 11 are provided in the respective gas supply passages. The primary sides of the solenoid valves 10 and 11 are gathered in one fuel supply passage 13 and connected to a gas proportional control valve 15. As a characteristic configuration of the present invention, a pressure sensor 16 is provided on the secondary side of the gas proportional control valve 15, more specifically, between the gas proportional control valve 15 and the solenoid valves 10 and 11. The pressure sensor 16 measures a pressure difference between the connection portion and the pressure guiding tube 17 portion. In the present embodiment, the pressure guiding tube 17 for detecting the reference pressure is provided in the burner case 2.
Extends inside. Therefore, by the pressure sensor 16,
The pressure difference between the pressure in the burner case 2 and the secondary side of the gas proportional control valve 15 is measured.

The heat exchanger 5 has, like a known water heater,
A flow sensor 20 for measuring the amount of incoming water and an incoming water temperature sensor 21 are provided on the inlet side, and a hot water temperature sensor 22 is provided on the outlet side.

On the other hand, the control of the combustion apparatus 1 is performed mainly by a control operation section 25 having a built-in microcomputer.
The control operation unit 25 has, in particular, a rotation speed control unit in addition to the functions of a known water heater. The rotation speed control means calculates an appropriate rotation speed of the fan 7 and controls the fan motor 8.

In the combustion apparatus 1 of the present embodiment, the signals from the flow rate sensor 20, the incoming water temperature sensor 21 and the outgoing water temperature sensor 22 are input to the control calculation section 25. Also, the rotation speed of the fan motor 8 is detected by the rotation speed detection means 26,
The signal is input to the control operation unit 25. Control operation unit 2
5 sends a signal to the fan driving means 2, and the fan driving means 2 is connected to a fan motor 8.

Further, the control operation unit 25 sends the valve control means 2
7, and the valve control means is operated by the gas proportional control valve 15
Is connected to The control operation unit 25 has a built-in microcomputer, but the signal sent to the valve control unit 27 is converted into an analog signal.

The signal from the pressure sensor 16 is directly input to the valve control means 27 and the control calculation section 25. Valve control means 2
Specifically, 7 includes three operation amplifiers 30, 31, and 32, as shown in FIG. Here, the first operation amplifier 30 forms a non-inverting amplifier circuit, and receives the signal V _S of the pressure sensor 16,
It is used merely to amplify the signal V _S of the pressure sensor 16. The second stage operation amplifier 31
A differential amplifier circuit is formed, and an amplified signal of the pressure sensor 16 is
It is input reference voltage V _P output from the control calculation unit 25, a signal corresponding to the difference therebetween is outputted. The capacitor C ₁ is provided at the site and constitutes an integration circuit. The operation amplifier 32 forms a differential amplifier circuit and outputs a difference between the integral value and the proportional control valve current. In the present embodiment, the operation amplifier 32 functions as a proportional valve drive circuit.

In the control calculation unit 25, a set temperature, a water input amount,
The amount of combustion gas is calculated from the incoming water temperature and the like, and the pressure of the gas and the number of burners on the secondary side of the gas proportional control valve 15 when discharging the amount of gas are determined. Here, when discharging the gas amount, the gas pressure in the secondary side portion of the gas proportional control valve 15 is often determined based on an empirical formula. Then, the reference voltage _VP is output from the gas pressure control terminal to the valve control means with the determined gas pressure as a target. At the same time, a pressure signal V _S on the secondary side of the gas proportional control valve 15 is input from the pressure sensor 16 to the valve control means 27, and the difference is amplified and the integration circuit is charged. Then, the gas proportional control valve 15 is driven by the output of the proportional valve drive circuit that operates based on the difference between the charged integrated value and the current of the proportional control valve. Therefore, the gas pressure on the secondary side of the gas proportional control valve 15 approaches the pressure determined by the control calculation unit 25. By this series of operations, the amount of gas from the burners 3 and 4 is controlled almost as desired. FIG. 3 is a block diagram showing a series of these controls.

If necessary, the control operation section 25 may be provided with a correction means. The correction means compares the actual calorific value of the burner, the signal of the pressure sensor expected when the calorific value is generated, and the signal of the actual pressure sensor, and corrects the signal of the pressure sensor. . That is, when the above-described valve control means 7 is employed, the operation amplifier 3
An error may occur due to an offset or the like of the circuit composed of 0, 31, and R _{1 to} R _2. The error is corrected by the control calculation unit 25. FIG. 4 shows a series of these controls in a block diagram.

In this embodiment, the signal of the pressure sensor 16 is also used for determining the rotation speed of the fan 7. That is, the control calculation unit 25 calculates the supply gas amount based on the signal of the pressure sensor 16 and the number of operating burners 3 and 4. Subsequently, the rotation speed control means calculates the rotation speed of the fan motor 8 for realizing the blowing corresponding to the gas amount. Then, a signal corresponding to the rotation speed is output to the fan driving means 2, and a predetermined current is supplied from the fan driving means 2 to the fan motor 8, so that the fan 7 is rotated. At this time, the rotation speed of the fan 7 is based on the gas amount calculated based on the signal of the pressure sensor 16, so that an appropriate amount of air can be obtained.

In the embodiment described above, the pressure sensor 1
6 is disposed outside the burner case 2 and the pressure guiding tube 17 is disposed inside the burner case 2. However, a normal type pressure sensor for measuring the difference between the external pressure and the connection portion is used. The same effect can be obtained by disposing it in case 2. FIG. 5 shows an example in which a pressure sensor 37 is attached to a gas flow path 36 near a nozzle 35 in the burner case 2. The mounting position of the pressure sensor may be anywhere as long as it is on the secondary side of the gas proportional control valve 15, but it is desirable to mount the pressure sensor as close to the gas proportional control valve 15 as possible. It is desirable to measure the pressure difference between the burner case 2 and the gas proportional control valve 15 with a pressure sensor, but the pressure of the gas on the secondary side of the gas proportional control valve 15 with respect to the atmospheric pressure is measured, and this signal is used. A considerable effect can be expected even if the configuration is performed.

In the above embodiment, the valve control means 27 as an analog circuit is provided with an integrating circuit and a proportional valve driving circuit. However, it is also possible to perform the integrating function on the microcomputer side (control operation section side). . FIG. 6 is a circuit diagram of the valve driving means when the integration function is performed on the microcomputer side (the control calculation section side).

[0030]

According to the first aspect of the present invention, since the pressure sensor is provided between the control valve and the burner, the accurate supply amount of the fuel can be known from the signal of the pressure sensor. Therefore, the combustion device of the present invention has an effect that a desired combustion amount can be obtained. Further, according to the configuration of the present invention, it is not necessary to adjust the control valve when the combustion device is installed or when the control valve is replaced.

According to the second aspect of the present invention, since the rotation speed of the fan is adjusted based on the pressure on the secondary side of the control valve, the amount of fuel supplied to the burner can be grasped more accurately, and the fan can be properly adjusted. There is an effect that the motor can be rotated at an appropriate rotational speed.

Further, according to the third aspect of the present invention, the pressure difference between the inside and outside of the burner can be accurately detected, and there is an effect that the amount of fuel can be grasped more accurately.

In the combustion device according to the fourth aspect, since the control valve is controlled proportionally and integratedly, the amount of supplied fuel quickly reaches the target value.

Further, in the combustion apparatus according to the fifth aspect, errors occurring at each stage can be corrected.

[Brief description of the drawings]

FIG. 1 is a block diagram of a combustion device according to an embodiment of the present invention.

FIG. 2 is a specific circuit diagram of the valve control means shown in FIG.

FIG. 3 is a block diagram of an embodiment of the present invention.

FIG. 4 is a block diagram of another embodiment of the present invention.

FIG. 5 is a sectional view showing a pressure sensor mounting portion according to another embodiment of the present invention.

FIG. 6 is a specific circuit diagram of valve control means according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Combustion device 2 Burner case 3, 4 Burner 5 Heat exchanger 7 Fan 8 Fan motor 15 Proportional control valve 16 Pressure sensor 17 Pressure guide tube 25 Control operation part 27 Valve control means

Claims (5)

[Claims] In a combustion apparatus having a burner, a control valve provided in a fuel supply passage for supplying fuel to the burner, and valve control means for adjusting an opening of the control valve, a pressure is applied to a secondary side of the control valve. A combustion device comprising a sensor, wherein an opening of a control valve is adjusted in accordance with a signal from the pressure sensor. 2. A burner, a control valve provided in a fuel supply path for supplying fuel to the burner, fuel control means for adjusting an opening of the control valve, a fan for supplying air to the burner, and a rotation of the fan A pressure sensor is provided on a secondary side of a control valve in a combustion device having a rotation speed control means for controlling the number of rotations, and a rotation speed of a fan is increased or decreased according to a combustion amount. A combustion device wherein the number of revolutions of a fan is adjusted. 3. The combustion apparatus according to claim 1, wherein the burner is disposed in a burner case, and the pressure sensor detects a pressure difference between the burner case and a secondary side of the control valve. . 4. The combustion device according to claim 1, wherein the control valve performs control including integral control. 5. A correction means for comparing an actual calorific value of a burner, a signal of a pressure sensor expected when the calorific value is generated, and a signal of an actual pressure sensor, and correcting the signal of the pressure sensor. 5. The method according to claim 1, wherein:
The combustion device according to any one of the above.