JPH0642743A - Sound muffling device in combustion device - Google Patents

Abstract

PURPOSE:To provide a sound muffling device for a combustion unit capable of increasing an effect of sound muffling in a low cost with a simple configuration in which accommodation can be applied to the combustion unit having a combustion noise and its aging variation is relatively patterned while an input of a burner is being fixed in particular. CONSTITUTION:This is a sound muffling device in a combustion unit having at least a burner 1 of either an input fixing type or a plurality of input switching type and a combustion chamber 2 as well as a discharging gas passage 5, wherein there are provided a sound wave generating unit 6 having a sound wave with an opposite phase of a predetermined mean noise waveform on the same type of combustion unit stored in advance and a speaker 7 arranged near either the combustion chamber 2 or the discharging gas passage 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silencer for a combustor.

[0002]

2. Description of the Related Art In a conventional muffler for an oil combustor, noise caused by driving an oil supply pump has been a major cause of noise. Moreover, in the conventional gas combustor,
Since there is no oil supply pump, the noise caused by the rotation of the blower fan is the main cause of noise, not the noise related to fuel supply. Most of the mufflers in the oil combustor are of resonance type and interference type, and in order to mitigate the low sound wave characteristic of the oil combustor, a large dimension muffler is required. did. on the other hand,
For example, in Japanese Patent Laid-Open No. 1-302026, etc., a detector for detecting the state of noise in the combustion chamber and a phase converter are provided, and sound waves of opposite phase are generated in real time in response to the generation of noise. A muffling device that muffles sound in this way is also provided.

[0003]

However, in the case of the above-mentioned conventional prompt response type silencer, even if it is said to be prompt response, it requires a certain amount of time required for a response, and a deviation occurs and the silencing effect is sufficient. I couldn't say that. Further, there is a drawback that the detector and the phase converter for prompt response are required, and the cost becomes high.

Therefore, the present invention solves the above-mentioned drawbacks of the prior art, and in particular, in a combustor in which the burner input is fixed or a plurality of stages can be switched, the combustion noise and its change over time are patterned. You can adapt to what you do,
An object of the present invention is to provide a silencer for a combustor, which has a simple structure and is low in cost and has a high silencing effect.

[0005]

To achieve the above object, a muffler for a combustor according to the present invention is provided with at least a burner of a fixed input type or a multiple input stage switching type, a combustion chamber, and an exhaust passage. And a sound wave generator in which a sound waveform having an opposite phase to an average noise waveform obtained in advance for a combustor of the same type is stored in advance, and a speaker arranged near the combustion chamber or the exhaust passage. The first feature is to have and. Further, a muffler for a combustor according to the present invention is a muffler for a combustor including at least a gas burner, a rotation speed multi-stage switching type blowing fan, a combustion chamber, and an exhaust passage. It has a sound wave generator that stores in advance each sound wave shape that has an opposite phase to the average noise waveform obtained in advance with respect to the rotation speed of each stage of the fan, and a speaker that is arranged near the combustion chamber or the exhaust passage. The second characteristic is that the sound wave shape corresponding to the rotation speed of the blower fan is generated.

[0006]

According to the first feature, when the combustion of the combustor is started, a sound wave having a waveform opposite in phase to the average combustion noise waveform of the combustor is generated from the speaker.
By combining the noise due to combustion and the sound wave emitted from the speaker, the amplitude of the noise waveform is reduced and the sound deadening effect is enhanced. In particular, in the combustor, the change in the sound from the time of ignition to the steady state is large in the initial stage, but it is possible to generate sound waves of the opposite phase of the noise that was previously learned at the same time from the start of combustion with no time lag. It is possible to effectively suppress the noise without delaying the change of noise in the early stage of combustion. Of course, for a combustor in which the fuel input is switched to multiple stages, noise data is taken in advance in a form corresponding to each of the fuel input stages, and a sonic waveform with the opposite phase is prepared for each. The prepared sound waves are generated in synchronization with the switching of the input. Further, according to the second feature, when a sound wave form for noise reduction corresponding to the rotation speed of each stage is generated from the speaker and the rotation speed of the blower fan is switched, the rotation speed after the switching is changed. A corresponding sound wave form for muffling is selected, output from the sound wave generator, and a sound wave is generated from the speaker. As a result, the noise is reduced according to the rotation speed of the blower fan.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view showing an embodiment of the device of the present invention.

An oil burner 1 is, for example, a gun type oil burner. This oil burner has a fixed fuel input, but it may be one that can be switched in stages. 2 is a combustion chamber, and the combustion chamber 2
A heat exchanger 4 having a water passage 3 is arranged therein. Combustion chamber 2
An exhaust passage 5 is connected to the ceiling portion of the. 6 is a sound wave generator, and 7 is a speaker that emits sound waves. The speaker 7 is attached so as to generate sound waves in the combustion chamber 2 where noise is generated and in the vicinity of the exhaust passage 5 where noise is discharged.

In the sound wave generator 6, a sound wave shape having a phase opposite to an average noise waveform based on data obtained in advance for a combustor of the same kind is stored in advance. Since the noise in the combustor differs depending on the type of combustor, the situation of the combustion noise of the combustor of the same type is preliminarily tested and frequency analysis is performed to select the average noise waveform. ,
A sound wave waveform having an opposite phase to this waveform is stored.
The noise waveform of the combustor has different noise waveforms at the beginning of combustion (that is, at the initial stage of ignition) and at the time of steady combustion. Therefore, the antiphase that continuously changes corresponding to the change in noise over time from the beginning of combustion to steady combustion It is preferable that the sound wave waveform of is generated from the start of combustion. Further, it is possible to switch the generated sound wave of the opposite phase between the initial stage of combustion and the steady state combustion.

In the case where the fuel input of the burner 1 is switched to several stages, the data about the combustion noise at each stage of fuel input is taken and the sound wave form of the opposite phase is stored in the sound wave generator 6. deep. Then, the waveform of the sound wave generated from the sound wave generator 6 is switched in association with the switching of the combustion input. The sound wave form output from the sound wave generator 6 is amplified by the speaker 7, and is emitted to the extent that it corresponds to the intensity of noise (amplitude of noise wave) in the combustor. The sound wave for silencing is emitted at the same time as the combustion of the combustor starts, and stopped at the same time as the end of combustion.

FIG. 2 is a sectional view showing another embodiment of the device of the present invention. 11 is a gas burner, a gas ejection nozzle
It has 18 and a gas supply governor 19. This gas burner shall be capable of switching the fuel input in stages. Reference numeral 12 is a combustion chamber, and a heat exchanger 14 having a water passage 13 is arranged in the combustion chamber 12. An exhaust passage 15 is provided in the ceiling of the combustion chamber 12.
Are connected. 16 is a sound wave generator with a built-in microcomputer,
Reference numeral 17 is a speaker that emits sound waves. The speaker 17 is attached so that sound waves are generated near the exhaust passage 15 through which noise is discharged. However, they may be mounted so that sound waves are generated in the combustion chamber 12 where noise is generated.
20 is a blower fan, and 21 is a rotation speed sensor of the blower fan 20.

For the combustor of the same type, the sound wave generator 16 stores in advance each sound wave shape having a phase opposite to the average noise waveform obtained in advance for each rotation speed of the blower fan by experiments. I will let you. Since the noise in the combustor differs depending on the type of combustor, the situation of the combustion noise of the combustor of the same type is preliminarily tested and frequency analysis is performed to select the average noise waveform. , A sound wave waveform having an opposite phase to this waveform is stored. Similarly, even in the same combustor, the generated noise differs depending on the rotation speed of the blower fan.Therefore, for each rotation speed of each switching stage, each sound waveform having an opposite phase to the average noise waveform obtained experimentally in advance is stored. Keep it. Simultaneously with the start of operation of the blower fan 20 accompanying the operation of the combustor, the stored sound wave shape is output from the sound wave generator 16 and emitted from the speaker 17. And fan
When the rotation speed of 20 is switched, the rotation speed sensor 21 detects the rotation speed, and this is input to the sound wave generator 16, whereby the sound wave generator 16 selects the sound wave shape corresponding to the rotation speed. Is output. The sound waves from the speaker 17 cancel out the noise, and the sound is muted. Generation of sound waves is also stopped by stopping the rotation of the blower fan 20 when the combustion operation ends.

[0013]

The present invention has the above-described structure and operation. According to the muffler for a combustor according to claim 1, the fixed input type or input multi-stage switching burner, the combustion chamber, and the exhaust passage are provided. A sound wave generator, which is provided at least and stores in advance a sound wave shape having an opposite phase to the average noise waveform obtained in advance for the same type of combustor, and a speaker arranged near the combustion chamber or the exhaust passage. Since it has a pre-stored anti-phase sound wave according to the combustion of the combustor, it closely responds to the noise of the type of combustor and sufficiently suppresses low frequency noise. It can be performed. Also, sound waves are generated not by feedback control but by feedforward, so
There is no phase shift compared to the feedback control. Moreover, the structure is simple and simple, and it can be manufactured at a sufficiently low cost. Further, according to the muffler for a combustor according to the second aspect, at least a gas burner, a fan for switching a plurality of rotational speeds, a combustion chamber, and an exhaust passage are provided. It has a sound wave generator that stores in advance each sound waveform that has an opposite phase to the average noise waveform obtained in advance for the number of rotations of each stage, and a speaker that is arranged near the combustion chamber or the exhaust passage. Since it is configured to generate a sound waveform corresponding to the rotation speed of the blower fan, in a combustor whose noise is mainly due to the blower fan, it is possible to muff the sound closely corresponding to the noise in the type of the combustor. . In addition, appropriate noise reduction can be performed in response to changes in the rotation speed of the blower fan.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram showing an embodiment of the device of the present invention.

FIG. 2 is a sectional configuration diagram showing another embodiment of the device of the present invention.

[Explanation of symbols]

 1 Oil burner 2 Combustion chamber 5 Exhaust passage 6 Sound wave generator 7 Speaker 11 Gas burner 12 Combustion chamber 15 Exhaust passage 16 Sound wave generator 17 Speaker 20 Blower fan 21 Rotation speed sensor

Claims (2)

[Claims] 1. A noise suppressor in a combustor having at least a fixed-input or multi-stage input-type burner, a combustion chamber, and an exhaust passage, and an average noise waveform obtained in advance for a combustor of the same type. A sound deadening device for a combustor, comprising: a sound wave generator in which a sound wave having a phase opposite to that of the sound wave generator is stored in advance; and a speaker arranged near the combustion chamber or the exhaust passage. 2. A muffler for a combustor, which comprises at least a gas burner, a blower fan capable of changing the number of revolutions, a combustion chamber, and an exhaust passage, and the rotation of each stage of the blower fan for a combustor of the same type. Of the blower fan, having a sound wave generator that stores in advance each sound wave shape that has an opposite phase to the average noise waveform obtained in advance with respect to the number, and a speaker that is arranged near the combustion chamber or the exhaust passage. A silencer for a combustor, which is configured to generate a sound waveform corresponding to the number of revolutions.