JP3301465B2 - Speaker device and silencer using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker device used in, for example, a high-temperature gas or a corrosive gas atmosphere, and a silencer using the speaker device.

[0002]

2. Description of the Related Art FIG. 9 shows an example of a muffler for an exhaust duct. High-temperature or corrosive exhaust gas flows inside the exhaust duct 10. The exhaust gas is, for example, 50
A high frequency muffler 6 of 0 Hz or more, and, for example, 80
Since the air is exhausted from the exhaust duct 10 through the muffler 8 for low frequency range of 5 Hz to 500 Hz, the exhaust noise is significantly reduced.

The volume of the high frequency range muffler 6 is relatively small, but the volume of the low frequency range muffler 8 is very large. For example, when the muffler 6 for high range has a diameter of about 0.6 m and a length of about 2 m, the muffler 8 for low range has a diameter of 5 m and a length of 30 m, and is installed in a room of a limited space building. It becomes a problem.

In order to solve the above-mentioned problem, there is a muffler for a low-frequency range formed by an electronic circuit as shown in FIG. That is, 80 Hz to 5 Hz is mainly applied to the exhaust duct 10.
A detection microphone 12 for picking up exhaust sound in a low frequency range of 00 Hz is provided, and an output signal of the detection microphone 12 is filtered by a filter 14 for generating an inverse phase signal;
The signal is amplified to an appropriate level by the amplifying unit 16, and a speaker 18 provided in the exhaust duct 10 is driven by an output signal of the amplifying unit 16.
The same level sound is supplied in a phase opposite to that of the low-frequency exhaust sound of Hz to 500 Hz, and the low-frequency exhaust sound in the exhaust duct 10 is muted. The monitor microphone 13 shown in FIG. 10 is for monitoring a mute state. By changing the characteristic of the filter 14 for generating an inverse phase signal based on the output signal of the monitor microphone 13, it is possible to cope with a temporal change of the acoustic system.

[0005]

However, the speaker 18
Is directly attached to the exhaust duct 10, the speaker 18
Are directly exposed to hot or corrosive exhaust gases. For this reason, the diaphragm of the speaker 18 is severely deteriorated,
There is a problem that the life is shortened.

[0006]

In order to solve the above-mentioned problems, a first invention of the present application is to provide a plurality of spaces provided in communication with a passage of a high-temperature or corrosive gas, A plurality of speakers provided in a state of loudspeaker, and a plurality of heat-resistant, corrosion-resistant drone cones provided in a state in which the respective speakers are hermetically shut off from the passages in the respective spaces, The resonance frequency of an acoustic resonance system including at least one of the plurality of spaces and the drone cone provided in this space is at least one other space and the drone cone provided in the other space. And a resonance frequency different from the resonance frequency of the acoustic resonance system.

[0007] The speaker device according to the second invention of the present application is a plurality of spaces provided in a state of communicating with a high-temperature or corrosive gas passage and adjacent thereto, and a boundary between these spaces. And a plurality of heat-resistant, corrosion-resistant drone cones provided in a state where each speaker is airtightly shut off from the passage in each space in each space. The resonance frequency of an acoustic resonance system including at least one of the plurality of spaces and the drone cone provided therein includes at least another space and the drone cone provided therein. It is characterized by being different from the resonance frequency of the acoustic resonance system.

[0008] A speaker device according to a third invention of the present application is the speaker device according to the first or second invention, wherein each of the spaces is provided via a nozzle-shaped duct having a narrow opening and a wide opening. The narrow duct of the nozzle-like duct is attached to the passage side, and the wide mouth is attached to the space side, and the sound radiated from each of the drone cones is provided substantially in the passage. It is characterized by being radiated from one point.

[0009] A speaker device according to a fourth invention of the present application is the speaker device according to the first or second invention, wherein the plurality of spaces are provided along a peripheral portion of the gas passage. It is characterized by the following.

[0010]

According to a fifth aspect of the present invention, there is provided a muffler according to any one of the first to fourth aspects, wherein:
A signal is supplied from a means for generating a signal having a phase opposite to the noise generated in the gas passage.

[0012]

According to the present invention, the space between the gas passage and the speaker is provided with a drone cone for making the speaker airtight with respect to the gas passage. Therefore, the speaker diaphragm is not directly exposed to the gas. Moreover,
Since a drone cone is used, the vibration from the speaker is transmitted to the gas passage through the drone cone. In addition, the drone cone itself that is directly exposed to gas is heat-resistant,
Since it has corrosion resistance, the drone cone itself has a long life.

[0013]

FIG. 1 shows a reference example on which the present invention is based. This reference example is also similar to the one shown in FIG. 10 and is a muffler for the low range of the exhaust duct. The detection microphone 24 provided in the duct 22 provided with the muffler for the high range uses the detection microphone 24 to reduce the exhaust gas sound. Mainly 80Hz to 500Hz
Is filtered by an anti-phase signal generation filter 26, amplified by an amplification unit 28 to substantially the same level as the 80 Hz to 500 Hz sound in the duct 22, and output from the amplification unit 28 It drives the speaker 30. The speaker 30 can output sound in a frequency band of, for example, 80 Hz to 500 Hz.

The speaker 30 is mounted on a box 32 provided on the side of the duct 22 in an airtight manner.
The box 32 has, for example, a hollow inside, and a speaker 30 is attached to a wall surface farthest from the duct 22 so as to face the duct 22 side. Therefore, the internal space of the box 32 becomes a buffer space 34. In addition,
Reference numeral 33 in FIG. 1 denotes a speaker box generally used to block output sound to the rear side of the speaker 30.

In the buffer space 34, for example, a box 3
A drone cone 36 is provided hermetically at the boundary between the duct 2 and the duct 22. This drone cone 36 is used for the diaphragm 3
6a and an edge 36b for connecting it to the box 32, and made of a material having excellent heat resistance and gas resistance, for example, stainless steel or titanium. In the acoustic resonance system including the drone cone 36 and the buffer space 34, the shape of the buffer space 34 and the characteristics of the drone cone 36 are selected so that the resonance frequency is, for example, 200 Hz.

In the muffler configured as described above, a signal collected by the detection microphone 24, filtered by the filter 26 for generating an inverse phase signal, and adjusted in level by the amplifier 28 is supplied to the speaker 30. As a result, the sound generated by the speaker 30 passes through the buffer space 34 and oscillates the diaphragm 36a of the drone cone 36. Therefore, the phase of the 80 Hz to 500 Hz exhaust gas sound generated here is provided in the duct 22. Is emitted, and the exhaust gas sound of 80 Hz to 500 Hz is muted.

At this time, the exhaust gas is supplied to the drone cone 36.
As a result, the speaker 30 is not damaged, so that the speaker 30 is not damaged. Moreover,
Since the drone cone 36 itself is also made of stainless steel or the like, it is not easily damaged even when exposed to corrosive exhaust gas at a high temperature. Although the drone cone 36 is provided at the boundary between the box 32 and the duct 22, it may be provided inside the box 34, that is, at a position closer to the speaker 30. Note that a monitor microphone 25 is provided downstream of the exhaust duct 22. The function of the microphone 25 is the same as that of the conventional monitor microphone 13.

When the sound of the speaker 30 is radiated into the duct 22 through the buffer space 34 and the drone cone 36,
There is a possibility that the frequency band in which sound can be emitted efficiently is limited to a narrow range. This is because the buffer space 34 and the drone cone 36 may form a sharp resonance point on the frequency axis. In such a case, the output of the speaker 30 can be efficiently radiated to the duct 22 at a frequency near the resonance point, but the radiation efficiency is significantly reduced at other frequencies. This point is improved in the first embodiment shown in FIG.

The speaker device according to the first embodiment is
A plurality of buffer spaces 341 to 343 are provided, and speakers 301 to 30 are respectively provided in the buffer spaces 341 to 343.
3 and the drone cones 361 to 363 are provided, and the resonance frequencies of the acoustic resonance systems including the buffer spaces 341 to 343 and the drone cones 361 to 363 provided therein are different for each buffer space. ing.

More specifically, when designing the speaker device according to the present embodiment, the target frequency band of 80 Hz to 500 Hz is divided into three frequency bands. Then, for example, three speakers 301 and 30 respectively sharing a first frequency band of 80 Hz to 150 Hz, a second frequency band of 150 Hz to 300 Hz, and a third frequency band of 300 Hz to 500 Hz.
2, 303 are provided. These speakers 301,
302, 303 are boxes 321, 322, 323
Are attached similarly to the speaker 30 of FIG.

These boxes 321, 322, 323
Have buffer spaces 341, 342 and 343 inside, and are arranged in a line along the length direction of the duct 22. Then, similarly to the first embodiment, the boxes 341, 342,
At the boundary between the 343 and the duct 22, the drone cones 361, 362, and 3 having the same configuration as the drone cone 36 in FIG.
63 is provided similarly to the drone cone 36 of FIG.

The box 321 emits sound from the speaker 301, but the drone cone 361 and the buffer space 3
The resonance frequency of the acoustic resonance system consisting of 41 is set to 115 Hz, which is approximately the center of the first frequency band. Similarly, the sound from the speaker 302 is radiated to the box 322, and the resonance frequency of the acoustic resonance system including the drone cone 362 and the buffer space 342 is set to 225 Hz, which is approximately the center frequency of the second frequency band. In addition, box 3
23, the sound from the speaker 303 is radiated, and the resonance frequency of the acoustic resonance system including the drone cone 363 and the buffer space 343 is substantially equal to the center frequency 40 of the third frequency band.
0 Hz. Each speaker 301, 302, 30
3 is supplied with a signal from the amplification unit 28.

In this manner, not only can the deterioration of the speakers 301 to 303 and the deterioration of the drone cones 361 to 363 be prevented, but also sound can be efficiently radiated to the duct 22 over the entire frequency band of 80 Hz to 500 Hz.

Next, a second embodiment is shown in FIG. In this embodiment, as in the first embodiment, the target frequency band of 80 Hz to 500 Hz is divided into a plurality of frequency bands, and three speakers 301 and 302 sharing the respective frequency bands are considered. , 303 are used, but boxes 3211, 3221, 32
Four are provided as indicated by 31 and 3241. These boxes 3211 to 3241 are arranged adjacent to each other along the length direction of the duct 22.

The speaker 301 is connected to the box 32
It is attached to the boundary between the boxes 3211 and 3221 so that sound can be radiated to both the buffer space 3411 of the box 11 and the buffer space 3421 of the box 3221. Similarly, speaker 302 has buffer space 3421 of box 3221 and buffer space 343 of box 3231.
Both boxes 322 so that sound can be radiated to both
1, 3231 are attached to the boundary. Further, the speaker 303 is connected to the buffer space 3 of the box 3231.
431 and 321 so that sound can be emitted to both the buffer space 3441 of the box 3241 and both boxes 3231 and 321.
41 are attached to the boundary portion. The boxes 3211, 3221, 3231, 3241 and the duct 22
At the boundary portion between them, drone cones 3611, 3621, 3631, and 3641 similar to the drone cone 36 of FIG. 1 are provided, respectively.

In this example, the frequency band of interest is divided into four frequency bands, that is, first to fourth frequency bands, and a drone cone 3 is assigned to each frequency band.
611, 3621, 3631, and 3641 are configured to correspond. Then, the buffer space 3421 of the box 3221 is set so that the resonance frequency of the acoustic resonance system including the buffer space 3411 of the box 3211 and the drone cone 3611 is substantially equal to the center frequency of the first frequency band.
The resonance frequency of the acoustic resonance system including the buffer space 3431 of the box 3231 and the drone cone 3631 is set to the third frequency such that the resonance frequency of the acoustic resonance system including the drone cone 3621 becomes substantially equal to the center frequency of the second frequency band. The buffer space 3441 of the box 3241 and the drone cone 364 are substantially equal to the center frequency of the frequency band.
1 are configured such that the resonance frequency of the acoustic resonance system composed of the first and second acoustic resonance systems is substantially equal to the center frequency of the fourth frequency band. With this configuration, sound is efficiently radiated to the duct 22 over the entire frequency band of 80 Hz to 500 Hz.

In this embodiment, four boxes 3
211 to 3241 and three speakers 301 to 303
However, the number of speakers used and the number of boxes can be arbitrarily changed as long as the relationship that the number of speakers is one less than the number of boxes is maintained. Also, instead of using multiple boxes,
The inside of one box may be partitioned into one more space than the number of speakers used.

In the first or second embodiment, each of the boxes 321 to 323 or 3211 to 3241 is attached by being dispersed along the length of the duct. It is generally difficult to fabricate the duct 22 so that such an attachment can be made, and in order to attach each of the boxes 321 to 323 or 3211 to 3241, the duct 22 is required.
Must be made a certain length or more, so that the entire device cannot be downsized. Further, the drone cones 361 to 363 or 3 serving as a sound source in the traveling direction of the sound wave.
Since 611 to 3641 are arranged, the impulse response of the entire speaker device becomes long. The problem that the impulse response becomes long can be solved by giving a filter for generating an anti-phase signal (not shown) an inverse characteristic of the impulse response. Since the filter is more complicated than that for a short impulse response, the filter for generating the inverse characteristic signal becomes large. The fact that the filter here is of a large scale means, for example, that FI
This means that the number of filter taps increases in the R filter, or the filter order increases in the IIR filter. FIGS. 4 and 5 improve these points.
This is a third embodiment shown in FIG. FIG. 4 is a sectional view taken along line AA of FIG.

In the third embodiment, each drone cone 361
Sounds radiated from 1,3621,3631 and 3641 are concentrated and radiated to almost one point of the duct 22 via the nozzle-shaped duct 40. By doing so, the acoustic path length from each of the drone cones 3611 to 3641 to the detection microphone (not shown) becomes substantially equal, and the impulse response of the whole speaker device can be shortened. Further, in order to attach such a duct 40 to the duct 22, it is only necessary that the duct 22 be processed so that only the narrow opening of the duct 40 is attached. Further, it is not necessary to lengthen the duct 22.

In the third embodiment, the nozzle-shaped duct 40
6 and FIG. 7 have improved this point.
A fourth embodiment shown in FIG. 8 and a fifth embodiment shown in FIG.

In the fourth embodiment, the boxes 3211 to 3241 are arranged along the periphery of the duct 22. In this way, the length of the duct 22 can be kept short without using the nozzle-shaped duct 40. Further, the impulse response of the entire speaker device does not become long. However, in such a configuration, the buffer space 3441 that radiates the highest sound and the buffer space 3411 that radiates the lowest sound are adjacent to each other, so that the sound in both buffer spaces is transmitted to each other. In order to prevent this, the partition wall 42 completely separates the boxes 3441 and 3411 from each other.

In the fifth embodiment shown in FIG.
The resonance frequencies of the acoustic resonance system including the 211 to 3241 and the drone cones 3611 to 3641 provided therein may be the same for all of the four boxes 3211 to 3241, or may be different for each box. Further, the opposing boxes may be the same. When the resonance frequency is the same for all four boxes, or when the opposing boxes are the same, the output sound pressures output from the respective boxes are added, so that the output efficiency can be increased. .

[0033]

As described above, according to the present invention, the loudspeaker is provided in a state in which the loudspeaker is provided in a space provided so as to be in communication with the passage of the high-temperature or corrosive gas, and the loudspeaker is positioned in the space relative to the passage. Heat-resistant in a state of airtight shut off,
Since the corrosion-resistant drone cone is provided, the speaker is not directly exposed to gas, and the diaphragm of the speaker is not damaged. Moreover, since the drone cone itself has heat resistance and corrosion resistance, the drone cone itself is not easily damaged.

In such a speaker device,
By providing a plurality of acoustic resonance systems each including a buffer space and a drone cone having different resonance frequencies, sound can be efficiently emitted over the entire target frequency band. Further, in the speaker device having the plurality of buffer spaces, the sound of the speaker is radiated to the gas passage through the nozzle-shaped duct, or the plurality of buffer spaces are formed along the periphery of the gas passage. With this arrangement, the speaker device can be easily attached to the gas passage, the whole device can be reduced in size, and the impulse response of the whole speaker device can be shortened. When used in the apparatus, the filter for generating the opposite phase signal does not need to be of a large scale.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a reference example of a speaker device according to the present invention.

FIG. 2 is a schematic configuration diagram of a first embodiment of a speaker device according to the present invention.

FIG. 3 is a schematic configuration diagram of the second embodiment.

FIG. 4 is a schematic configuration diagram of the third embodiment.

FIG. 5 is a schematic perspective view of the third embodiment.

FIG. 6 is a partially omitted perspective view of the fourth embodiment.

FIG. 7 is a sectional view of the fourth embodiment.

FIG. 8 is a sectional view of the fifth embodiment.

FIG. 9 is a schematic configuration diagram showing a conventional technique.

FIG. 10 is a schematic configuration diagram showing a conventional technique.

[Explanation of symbols]

22 Duct (exhaust gas passage) 26 Anti-phase signal generation filter (anti-phase signal generation means) 30 301 to 303 Speaker 34 341 to 343 3411 to 3441 Buffer space 36 361 to 363 3611 to 3641 Drone cone

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takeo Shindo 7-2-1, Minatojima-Nakamachi, Chuo-ku, Kobe-shi, Hyogo Inside TOA Co., Ltd. (56) References JP-A-2-141095 (JP, A) 1-133892 Kaihei (JP, U) Actually open 64-2815 (JP, U)

Claims (5)

(57) [Claims] 1. A plurality of spaces provided so as to communicate with a passage of a high-temperature or corrosive gas, a plurality of speakers provided so as to vocalize in these spaces; A plurality of heat-resistant, corrosion-resistant drone cones provided in a state of being airtightly shut off with respect to at least one of the plurality of spaces and the drone cone provided in this space. Wherein the resonance frequency of the acoustic resonance system is different from the resonance frequency of the acoustic resonance system including at least another space and the above-mentioned drone cone provided in the other space. 2. A plurality of spaces provided in communication with a high-temperature or corrosive gas passage and adjacent to each other, and a plurality of spaces provided on each boundary of these spaces so as to open up to both spaces. A speaker, comprising a plurality of heat-resistant, corrosion-resistant drone cones provided in a state where each speaker is airtightly shut off from the passage in each of the spaces,
The resonance frequency of the acoustic resonance system including at least one of the plurality of spaces and the drone cone provided therein is the same as that of the acoustic resonance system including the at least one other space and the drone cone provided therein. A speaker device characterized by being different from a resonance frequency of a system. 3. The speaker device according to claim 1, wherein each of the spaces is provided in a state of communicating with the gas passage through a nozzle-like duct having a narrow opening and a wide opening. A speaker having a narrow opening formed on the side of the passage and a wide opening formed on each side of the space, and radiating sound radiated from each of the drone cones at substantially one point in the passage. . 4. The speaker device according to claim 1, wherein the plurality of spaces are provided along a peripheral portion of the gas passage. 5. A muffler, wherein a signal from a means for generating a signal having a phase opposite to that of noise generated in the gas passage is supplied to the speaker device according to any one of claims 1 to 4 .