JPH06288539A - Combustion apparatus - Google Patents

Abstract

PURPOSE:To embody a low noise combustion apparatus capable of reducing internal noise by making use of adaptive active control where pressure variations of an opposite phase to a combustion sound is outputted from a fuel control device. CONSTITUTION:A microphone which is a pressure detector 19 provided in a combustion chamber detects pressure variations of a combustion sound as sound pressure, and a computation device 20 estimates an opposite phase signal of the combustion sound based upon the foregoing detected pressure variations. A combustion control device 10 outputs opposite phase pressure variations to offset pressure variations produced in the combustion chamber with phase interference. Further, an estimation of the amount of sound deadening is also ensured on the basis of the signal from the pressure detector 19 in the combustion chamber. Thus, a varying combustion sound is minimized at all times with the adaptive control, and the combustion sound is reduced and vibratory combustion is previously prevented from being produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion system which has a function of actively muffing combustion noise of a combustion apparatus for burning gas or the like by calculating a signal having a phase opposite to a pressure fluctuation generated by combustion and phase interference. It relates to the device.

[0002]

2. Description of the Related Art As a conventional water heater with a silencer, there is one disclosed in Japanese Utility Model Laid-Open No. 4-95266. As shown in FIG. 9, the combustion signal applied to the burner 1 is received from the combustion operation device 2 to mute the sound. The noise to be silenced is the noise generated during steady combustion of the blower 3 and the burner 1,
These noise sources are detected by the two microphones 4 and 5, and the sound is silenced by the two speakers 6 and 7. The mute controller 8, the microphones 4 and 5, and the speakers 6 and 7 are incorporated inside the water heater. .

[0003]

However, in the above-mentioned conventional configuration, since the generated noise is silenced by the speaker, there is a problem that the noise source cannot be fundamentally taken as a countermeasure. Further, since a speaker for suppressing noise and two microphones for detecting noise are provided, there is a problem that the installation space and cost of the speaker and the microphone are increased. Further, since the sound of the noise source is detected by the microphone and the signal of the opposite phase is reproduced from the speaker, there is a problem that howling is likely to occur due to acoustic feedback.

The present invention solves the above-mentioned problems, and fundamentally suppresses the noise generated by active noise reduction that incorporates adaptive control of the combustion noise generated when operating the combustion device, and also suppresses howling. Completely suppresses oscillating combustion regardless of combustion load fluctuations and exhaust variations, and realizes noise reduction by using conventional combustion equipment as it is.
It is an object of the present invention to provide a low-noise combustion device that has a simple structure and is inexpensive.

[0005]

In order to achieve the above object, a combustion apparatus of the present invention comprises an air blower for supplying air, a fuel controller for supplying fuel, a burner section for mixing air and fuel, and a burner. Based on the signals from the combustion chamber that burns the mixed gas mixed in the section, the exhaust passage and the exhaust port that discharges the exhaust gas from the combustion chamber, the pressure detector that detects the pressure fluctuations in the combustion chamber, and the signal from the pressure detector. In addition, an arithmetic unit for calculating a signal in which the pressure fluctuation in the combustion chamber is suppressed by phase interference is provided by adaptive control.

Further, the combustion apparatus of the present invention includes a blower for supplying air, a fuel controller for supplying fuel, a burner section for mixing air and fuel, and a combustion chamber for burning the mixed gas mixed in the burner section. A heat exchanger that transfers the heat of the exhaust gas generated in the combustion chamber, an exhaust passage and an exhaust port that discharge the exhaust gas through the heat exchanger, and a pressure detector that detects the pressure fluctuation in the exhaust passage. An arithmetic unit for calculating a signal in which the pressure fluctuation in the combustion chamber is suppressed by phase interference based on the signal of the pressure detector by adaptive control is provided.

Further, the combustion apparatus of the present invention comprises a blower for supplying air, a fuel controller for supplying fuel, a burner section for mixing air and fuel, and a combustion chamber for burning the mixed gas mixed in the burner section. An exhaust passage and an exhaust port that exhaust the exhaust gas from the combustion chamber, a pressure detector that detects pressure fluctuations in the combustion chamber, a filter that filters the signal of the pressure detector, and a signal that has passed through the filter. Based on the above, an arithmetic unit for calculating a signal in which the pressure fluctuation in the combustion chamber is suppressed by phase interference is provided by adaptive control.

[0008]

According to the present invention, due to the above-described structure, first, the combustion causes a pressure fluctuation in the combustion chamber. This pressure fluctuation propagates to the burner section and the exhaust passage. The pressure detector attached to the combustion chamber detects the pressure fluctuation due to the combustion.
This signal is taken into the arithmetic device, which calculates a signal having a phase opposite to this signal and inputs it to the fuel control device. The anti-phase signal input to the fuel control device causes pressure fluctuation in the fuel in a phase opposite to the combustion noise and propagates to the combustion chamber. The pressure fluctuation in the combustion chamber is suppressed by the phase interference caused by the pressure fluctuation in the opposite phase applied to the fuel. Thereby, the vibration of the flame generated by the combustion is suppressed, and the combustion noise is reduced.
Further, the arithmetic unit also determines the muffling effect of the combustion sound, and when the muffling volume is small, adjusts the phase and output of the anti-phase signal so that the muffling volume becomes maximum. That is, the signal processing in the arithmetic unit incorporates an adaptive control algorithm so as to follow up even when the combustion sound changes, and calculates the inverse characteristic of the combustion sound in real time. In addition, for oscillating combustion that occurs when load fluctuations occur during combustion, the same operation as above also allows the computing unit to calculate the anti-phase signal based on the pressure fluctuations detected in the combustion chamber, and to control the fuel control. By applying an anti-phase signal to the device, pressure fluctuation and phase interference due to oscillatory combustion occur in the combustion chamber, and the oscillatory combustion is eliminated.

Further, pressure fluctuations and severe flow turbulence are generated in the combustion chamber due to combustion, but a rectifying action works in the process of propagating these to the exhaust passage through the heat exchanger, and turbulent noise is suppressed and exhaust gas is suppressed. Only the pressure fluctuation is efficiently detected by the pressure detector provided in the passage.

Further, by providing a filter for passing only the main band of the combustion sound to the signal of the pressure detector, howling caused by acoustic feedback is suppressed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the gas water heater shown in FIGS.

As shown in FIG. 1 and FIG. 3, an air blower 9 composed of a sirocco fan for supplying combustion air, a proportional valve 10 for controlling the amount of fuel gas, and a valve control for controlling the proportional valve 10. A burner unit 13, a burner unit 13 for mixing gas and air, a combustion chamber 14 for burning the above-mentioned air-fuel mixture, an exhaust passage 16 for discharging exhaust gas to the outside of the main body 15 of the water heater, an exhaust port 17, and Heat exchanger 18 that transfers heat to water
Consists of. Then, based on a signal from the pressure detector 19 composed of a microphone provided in the combustion chamber 14 in order to take out the pressure fluctuation generated by the combustion, the pressure fluctuation is suppressed by the phase interference of the pressure fluctuation of the opposite phase. A calculation device 20 for calculating a signal, a DC controller 21 inside the valve controller 12 for applying a DC voltage for controlling the gas amount of the proportional valve 10, and a DC / DC for mixing this DC voltage and an antiphase signal.
It is configured to include an AC mixer 22.

The proportional valve 10 is of a moving coil type having a light drive portion and excellent response characteristics, and has a gas inlet 23, an outlet 24, a valve seat 25, a valve body 26, and a valve body 26. Spring 27 for pushing up, magnet 28 and coil 29 for pushing down valve body 26, coil 29 and valve body 2
And a shaft body 30 connecting the six. Further, as shown in FIG. 2, the arithmetic unit 20 further includes a first amplifier 31 for amplifying a signal from the pressure detector 19 including a microphone and an A / D converter 32 for converting an analog signal into a digital signal.
And a divider 33 that divides the signal from the A / D converter 32 into two, a digital filter device 34 that calculates an inverse characteristic based on the signal from the divider 33, and evaluates the volume of the combustion noise. An adaptive filter device 35, a D / A converter 36 for converting the calculated digital anti-phase signal into an analog signal,
It is composed of a second amplifier 37 which amplifies this signal.

According to the above construction, the combustion chamber 14 is formed by combustion.
The pressure fluctuations that occur inside are directly detected by the pressure detector 1 as sound pressure.
It is detected at 9 and is taken into the arithmetic unit 20. In the arithmetic unit 20, the captured signal is amplified by the first amplifier 31, converted into a digital signal by the A / D converter 32, and then distributed by the distributor 33 into two signals, one of which is a digital filter. It is captured by the device 34. An anti-phase signal of the combustion sound is calculated based on this signal. The calculated anti-phase signal passes through the adaptive filter device 35, is converted into an analog signal by the D / A converter 36, is amplified by the second amplifier 37, and then is DC / AC mixer 22 of the valve controller 12. The pressure fluctuation of the opposite phase is output from the proportional valve 10 to the combustible gas. That is, the proportional valve 10 pushes the valve body 26 downward against the spring 27 via the shaft body 30 by the action of the electromagnetic force of the magnet 28 and the coil 29 by the DC voltage from the DC controller 21, so that the valve seat 25 and the valve body 25 are pushed down. Keeping the gap of 26 constant,
The amount of combustion is controlled by keeping the gas flow rate constant. When the antiphase signal mixed by the DC / AC mixer 22 is applied to the coil 29 in the state of the constant valve opening, the valve body 26 vibrates by the action of the electromagnetic force, and the valve seat 25 and the valve body 25 are vibrated. The gap of 26 fluctuates, and the pressure fluctuation of the opposite phase is superimposed on the gas. The gas accompanied by the anti-phase pressure fluctuation is mixed with air in the burner section 13, then propagates to the combustion chamber 14, and the combustion noise is silenced by phase interference. Thereby, the vibration of the flame generated by the combustion can be suppressed, so that the combustion noise of the gas water heater discharged from the exhaust port 17 can be reduced and the occurrence of the oscillating combustion can be prevented.

Here, in the normal active muffling configuration, the optimum muffling effect cannot be obtained unless an evaluation microphone for evaluating the muffling volume is provided. However, this time, it was newly found that the pressure fluctuation generated by combustion inside the closed space such as a gas water heater is a periodic fluctuation. For this reason, it was confirmed that the microphone, which is the pressure detector 19, can be used to muffle sound.

That is, the pressure fluctuation detected in the combustion chamber 14 cancels the pressure fluctuation generated in the combustion chamber 14 after several cycles. Then, the other signal of the pressure fluctuation signal distributed by the distributor 33 passes through the digital filter device 34 and is captured by the adaptive filter device 35. In the adaptive filter device 35, the filter coefficient for calculating the anti-phase signal is changed so as to minimize the combustion noise, the phase and the gain of the output signal are adjusted, and the adaptive control for constantly minimizing the changing combustion noise is executed.

It is difficult to reduce low-frequency noise (100 to 300 Hz), which is the main band of combustion noise, by sound insulation and sound absorption, which are conventional methods for reducing combustion noise of gas water heaters.
Since the combustion load changes with each exhaust variation, it was necessary to design the burner to suppress oscillatory combustion. On the other hand, according to the present invention, the combustion noise can be significantly reduced by the above-mentioned operation, and the oscillating combustion caused by the fluctuation of the combustion load and the exhaust variation can be completely suppressed by one burner design. That is, the time required for burner design can be shortened.

Further, in the conventional active muffling configuration, a speaker and two microphones have to be provided for muffling, but since a means for generating an opposite phase can be realized by the proportional valve 10 which is the fuel control device, another speaker is provided. A pressure detector 19 for detecting combustion noise, which is periodic noise, which is unnecessary.
That is, since the sound can be silenced by providing one microphone, the installation space is small and the adaptive active noise reduction can be realized at a low cost.

Here, a pressure detector 19 for detecting pressure fluctuations
By using a vibration pickup instead of the microphone, the pressure fluctuation can be detected as vibration and the sound can be suppressed, and howling due to acoustic feedback can be suppressed.

Next, another embodiment of the present invention will be described with reference to FIGS. The parts having the same structure as those of the first embodiment and having the same function are designated by the same reference numerals, and detailed description thereof will be omitted, and different parts will be mainly described.

A blower 9 for supplying combustion air, a proportional valve 10 for controlling the amount of gas as fuel, and the proportional valve 10
A burner unit 13 for mixing gas and air, a combustion chamber 14 for burning the air-fuel mixture, an exhaust passage 16 for discharging exhaust gas to the outside of the body 15 of the water heater, and an exhaust port 17. , A heat exchanger 18 that transfers the heat of combustion to the water,
Consists of. The heat exchanger 18 is provided with a water passage 38 and a large number of heat absorbing plates 39. Then, based on the signal of the pressure detector 19 provided in the exhaust passage 16 in order to take out the pressure variation generated by the combustion, and the signal of the pressure variation suppressed by the phase interference of the pressure variation of the opposite phase, An arithmetic unit 20 for calculating and a DC controller 21 for applying a DC voltage for controlling the gas amount by the proportional valve 10 of the valve controller 12.
And a DC / AC mixer 22 for mixing the DC voltage and the anti-phase signal.

With the above-described structure, the pressure fluctuation generated in the combustion chamber 14 propagates to the exhaust passage 16 through the space between the heat absorbing plates 39 of the heat exchanger 18 together with the exhaust gas accompanied by the turbulent flow. At this time, the turbulence of the flow of the exhaust gas is caused by the heat absorption plate 3
Turbulent noise is suppressed by the rectifying action of 9, and the pressure detector 19 provided in the exhaust passage 16 can faithfully detect only the pressure fluctuation. With this, it is possible to faithfully output the pressure fluctuation generated by the combustion as the pressure fluctuation of the opposite phase from the proportional valve 10, and the silencing effect is improved.

Further, as shown in FIG. 6, even if the pressure detector 19 is provided in the burner portion 13, the sound deadening effect can be similarly exerted, and since the pressure detector 19 is provided on the upstream side of the combustion chamber 14, Performance deterioration of the pressure detector 19 due to heat can be suppressed.

Next, another embodiment of the present invention will be described with reference to FIG. The parts having the same structure as those of the first embodiment and having the same function are designated by the same reference numerals, and detailed description thereof will be omitted, and different parts will be mainly described.

The signal taken in by the pressure detector 19 is amplified by the first amplifier 31, converted into a digital signal by the A / D converter 32, and then distributed by the distributor 33 into two signals. It is filtered by a bandpass filter 40, which is a filter that passes only the frequency band of the combustion sound, and is taken into the digital filter device 34. An anti-phase signal of the combustion sound is calculated based on this signal. The calculated anti-phase signal passes through the adaptive filter device 35, is converted into an analog signal by the D / A converter 36, is amplified by the second amplifier 37, and then is DC / AC mixer 22 of the valve controller 12. The pressure fluctuation of the opposite phase is output from the proportional valve 10 to the combustible gas. The other signal of the pressure fluctuation signal distributed by the distributor 33 passes through a high-pass filter 41, which is a filter that passes frequencies higher than the main band of the combustion sound, and is taken into the digital filter device 34 and then to the adaptive filter device 35. It is captured. In the adaptive filter device 35, the filter coefficient for calculating the anti-phase signal is changed so as to minimize the combustion noise, the phase and the gain of the output signal are adjusted, and the adaptive control for constantly minimizing the changing combustion noise is executed.

Due to the operation of the above signal processing, howling does not occur particularly in a low frequency region other than the main band of the combustion sound.
That is, it is possible to solve the problem that it is difficult to apply active noise suppression due to a problem peculiar to combustion that low-frequency sound pressure is amplified by the combustion action.

The same effect can be obtained even if the bandpass filter 40 is provided in the subsequent stage of the adaptive filter device 35.

[0028]

As described above, in the combustion apparatus of the present invention, the pressure fluctuation generated by combustion is detected by the pressure detector provided in the combustion chamber, and based on this signal, the pressure fluctuation is always optimized by phase interference. The suppressed anti-phase signal is calculated by adaptive control, and the fuel control means outputs the anti-phase pressure fluctuation to the fuel by this anti-phase signal, so that the fluctuating combustion noise in the combustion chamber is reduced by the phase interference. Since the vibration of the flame generated by the combustion can be suppressed, it is possible to reduce the combustion noise of the combustion device that comes out of the exhaust port and prevent the occurrence of the oscillatory combustion. Furthermore, since the fluctuation in combustion load and oscillating combustion caused by exhaust variation can be completely suppressed by one burner design, the time required for burner design can be greatly shortened. further,
Since there is no need to newly install a speaker to suppress noise and only one pressure detector is required, it can be installed in a conventional combustion device as it is because the installation space is small, and an adaptive active muffling configuration is realized at low cost. it can.

In the structure in which the pressure detector is provided in the exhaust passage,
By suppressing the effect of noise generated by the flow of exhaust gas when it receives a rectifying action when the exhaust gas passes through the heat exchanger,
Combustion sound and vibration combustion sound can be detected faithfully, the silencing effect is improved, and vibration combustion can be suppressed in advance.

Further, by providing a filter for the signal of the pressure detector, it becomes possible to detect only the main band of the combustion noise, and howling caused by acoustic feedback can be suppressed.

[Brief description of drawings]

FIG. 1 is a front view of a gas water heater adopting an embodiment of a combustion apparatus of the present invention.

FIG. 2 is a block diagram of the inside of the arithmetic unit of the same device.

FIG. 3 is an enlarged cross-sectional view of a fuel control device of the same device.

FIG. 4 is a front view of a gas water heater using another embodiment of the combustion apparatus of the present invention.

FIG. 5 is an enlarged cross-sectional view of a heat exchanger of the same device.

FIG. 6 is a front view of a gas water heater using another embodiment of the combustion apparatus of the present invention.

FIG. 7 is a block diagram of the inside of an arithmetic unit adopting another embodiment of the combustion apparatus of the present invention.

FIG. 8 is a block diagram of the inside of an arithmetic unit adopting another embodiment of the combustion apparatus of the present invention.

FIG. 9 is a side sectional view of a conventional gas water heater.

[Explanation of symbols]

 9 Blower device 10 Fuel control device 13 Burner part 14 Combustion chamber 16 Exhaust passage 17 Exhaust port 18 Heat exchanger 19 Pressure detector 20 Arithmetic device

Claims (3)

[Claims] 1. A blower device for supplying air, a fuel control device for supplying fuel, and a burner section for mixing air and fuel.
A combustion chamber that burns the mixed gas mixed in the burner section, an exhaust passage and an exhaust port that discharge exhaust gas from the combustion chamber, a pressure detector that detects a pressure fluctuation in the combustion chamber, and the pressure detection. Of a signal in which the pressure fluctuation of the combustion chamber is suppressed by phase interference based on the signal of a fuel cell, and a combustion device in which an anti-phase signal of the calculation device is generated as a pressure fluctuation by the fuel control device . 2. A blower unit for supplying air, a fuel control unit for supplying fuel, and a burner section for mixing air and fuel.
A combustion chamber that burns the mixed gas mixed in the burner section, a heat exchanger that transfers the heat of the exhaust gas generated in the combustion chamber, and an exhaust passage that passes through the heat exchanger and discharges the exhaust gas. And an exhaust port, a pressure detector for detecting pressure fluctuations in the exhaust passage, and an arithmetic unit for calculating a signal in which pressure fluctuations in the combustion chamber are suppressed by phase interference based on signals from the pressure detector by adaptive control. And a combustion device that generates an anti-phase signal of the arithmetic unit as pressure fluctuations by the fuel control device. 3. A blower device for supplying air, a fuel control device for supplying fuel, a burner section for mixing air and fuel,
A combustion chamber that burns the mixed gas mixed in the burner section, an exhaust passage and an exhaust port that discharge exhaust gas from the combustion chamber, a pressure detector that detects a pressure fluctuation in the combustion chamber, and the pressure detection. Filter for filtering the signal of the compressor, an arithmetic unit for calculating a signal in which the pressure fluctuation of the combustion chamber is suppressed by phase interference by adaptive control based on the signal that has passed through the filter, and a reverse phase of the arithmetic unit A combustion device that produces a signal as a pressure fluctuation by the fuel control device.