JPH0819083A - Speaker device and silencer using the same - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent damage to the speaker used in the muffler of the exhaust duct due to exhaust gas. [Structure] The sound of gas flowing through the exhaust duct 22 is picked up by the microphone 24, and is made into an antiphase by the antiphase signal generator,
The sound is amplified by the amplification unit 28 and radiated by the speaker 30 to the duct 22 to mute the sound. The speaker 30 is a speaker box 32.
Installed in the speaker box 32 and a buffer space
A drone cone 36 including a diaphragm 36a and an edge 36b is provided so as to hermetically shield the boundary between the duct 34 and the duct 22. The drone cone 36 has heat resistance and corrosion resistance. The speaker 30 is ducted by this drone cone 36.
Since it is not directly exposed to the gas inside 22, and the drone cone 36 itself is heat and corrosion resistant, it is not easily damaged.

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 corrosive gas atmosphere, and a silencer using the speaker device.

[0002]

2. Description of the Related Art FIG. 9 shows an example of a silencer for an exhaust duct. Exhaust gas having high temperature or corrosiveness is flowing inside the exhaust duct 10. Exhaust gas is, for example, 50
Muffler 6 for high range above 0 Hz, and for example 80
Since it is discharged from the exhaust duct 10 after passing through the low-frequency muffler 8 of Hz to 500 Hz, exhaust noise is significantly reduced.

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

In order to solve the above-mentioned problem, there is a muffler for low frequency range which is composed of an electronic circuit as shown in FIG. That is, the exhaust duct 10 mainly has a frequency of 80 Hz to 5 Hz.
A detection microphone 12 for collecting exhaust sound in the low sound range of 00 Hz is provided, and the output signal of the detection microphone 12 is filtered by the antiphase signal generation filter 14.
The amplification section 16 amplifies the signal to an appropriate level, and the output signal of the amplification section 16 drives the speaker 18 provided in the exhaust duct 10 to generate 80 in the exhaust duct 10.
A low level exhaust sound in the low frequency range of Hz to 500 Hz is supplied with the same level of sound in the opposite phase to muffle the low frequency exhaust sound in the exhaust duct 10. The monitor microphone 13 shown in FIG. 10 is for monitoring the mute state. By changing the characteristics of the anti-phase signal generation filter 14 based on the output signal of the monitor microphone 13, it is possible to cope with the temporal change of the acoustic system.

[0005]

However, the speaker 18
Is attached directly to the exhaust duct 10, the speaker 18
Diaphragms are directly exposed to hot or corrosive exhaust gases. Therefore, the diaphragm of the speaker 18 is severely deteriorated,
There was a problem that the life was shortened.

[0006]

In order to solve the above problems, the speaker device according to the first invention of the present application is a space provided in a state of communicating with a passage of high temperature or corrosive gas, The speaker includes a loudspeaker installed in the space and a heat- and corrosion-resistant drone cone installed in the space to hermetically shield the speaker from the passage.

The speaker device according to the second invention of the present application includes a plurality of spaces provided in a state of communicating with a passage of high temperature or corrosive gas, and a plurality of speakers provided in a state of expanding into this space. A plurality of heat-resistant and corrosion-resistant drone cones provided in a state of hermetically shutting off each speaker from the passage in each of the spaces, and at least one space of the plurality of spaces. The resonance frequency of the acoustic resonance system including the drone cone provided in this space is different from the resonance frequency of the acoustic resonance system including at least the other space and the drone cone provided in the other space. It is characterized by.

A speaker device according to a third invention of the present application is provided at a plurality of spaces provided in a state of communicating with a passage of a high temperature or corrosive gas and adjacent to each other, and at a boundary between these spaces. A plurality of loudspeakers, and a plurality of heat-resistant and corrosion-resistant drone cones that are provided to hermetically shut off the loudspeakers from the passages in each of the spaces. The resonance frequency of the acoustic resonance system composed of one space and the drone cone provided therein is different from the resonance frequency of the acoustic resonance system composed of at least another space and the drone cone provided therein. It is characterized by.

A speaker device according to a fourth invention of the present application is the speaker device according to the second or third invention, wherein each space is provided with a nozzle-shaped duct having a narrow mouth portion and a wide mouth portion. It is characterized in that it is provided so as to communicate with the gas passage, and the narrow mouth portion of the nozzle duct is attached to the passage side and the wide mouth portion is attached to the space side.

A speaker device according to a fifth invention of the present application is the speaker device according to the second or third invention, wherein the plurality of spaces are provided along a peripheral portion of the gas passage. It is characterized by.

A silencer according to a sixth invention of the present application is a signal from a means for generating a signal having a phase opposite to the noise generated in the gas passage in the speaker device according to the first to fifth inventions. It is characterized by supplying.

[0012]

According to the present invention, a drone cone is provided in the space between the gas passage and the speaker to make the speaker airtight with respect to the gas passage. Therefore, the diaphragm of the speaker is not directly exposed to the gas. Moreover,
Since the drone cone is used, the vibration from the speaker is propagated to the gas passage through the drone cone. Also, the drone cone itself, which is directly exposed to gas, is heat resistant,
Since it has corrosion resistance, the drone cone itself has a long life.

[0013]

EXAMPLE A first example is shown in FIG. Similar to that shown in FIG. 10, this embodiment is also a muffler for the low sound range of the exhaust duct, and the detection microphone 24 provided in the duct 22 provided with the muffler for the high sound range detects the exhaust gas noise. Mainly, a sound of 80 Hz to 500 Hz is picked up, filtered by the anti-phase signal generating filter 26, amplified by the amplifying unit 28 to almost the same level as the sound of 80 Hz to 500 Hz in the duct 22, and the amplifying unit The output of 28 drives the speaker 30. This speaker 30 is, for example, 80 Hz
It is possible to output a sound in a frequency band of to 500 Hz.

The speaker 30 is attached to a box 32 which is airtightly provided on the side surface of the duct 22.
The box 32 has, for example, a hollow interior, and the speaker 30 is attached to the wall surface farthest from the duct 22 so as to face the duct 22. Therefore, the internal space of the box 32 becomes the buffer space 34. In addition,
The reference numeral 33 in FIG. 1 is a speaker box that is generally used for sealing the output sound to the rear side of the speaker 30.

In the buffer space 34, for example, the box 3
A drone cone 36 is hermetically provided at the boundary between the duct 2 and the duct 2. This drone cone 36 is a diaphragm 3
6a and an edge 36b connecting this to the box 32, and is made of a material having excellent heat resistance and gas resistance, such as 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, the characteristics of the drone cone 36, and the like are selected so that the resonance frequency is, for example, 200 Hz.

In the muffler having the above-described structure, the signal picked up by the detection microphone 24, filtered by the anti-phase signal generating filter 26, and level-adjusted 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 vibrates the diaphragm 36a of the drone cone 36. Therefore, in the duct 22, the phase of the exhaust gas sound of 80 Hz to 500 Hz generated here is generated. Is emitted and the exhaust gas sound of 80 Hz to 500 Hz is silenced.

At this time, the exhaust gas is the drone cone 36.
Since it is prevented from entering the buffer space 34 by the, the speaker 30 is not damaged. Moreover,
Since the drone cone 36 itself is also made of stainless steel or the like, it is hard to be damaged even when exposed to corrosive exhaust gas at 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. A monitor microphone 25 is provided on the downstream side of the exhaust duct 22. The function of the microphone 25 is similar to 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,
The frequency band in which sound can be efficiently emitted may be 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 second embodiment shown in FIG.

The speaker device according to the second embodiment is
A plurality of buffer spaces 341 to 343 are provided, and the speakers 301 to 30 are provided in the buffer spaces 341 to 343, respectively.
3 and the drone cones 361 to 363 are provided, and the resonance frequencies of the acoustic resonance systems composed of 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 this embodiment, the target frequency band of 80 Hz to 500 Hz is divided into three frequency bands. Then, for example, the three speakers 301, 30 that share the first frequency band of 80 Hz to 150 Hz, the second frequency band of 150 Hz to 300 Hz, and the third frequency band of 300 Hz to 500 Hz, respectively.
2, 303 are provided. These speakers 301,
302 and 303 are boxes 321, 322 and 323.
The speaker 30 is mounted similarly to the speaker 30 of the first embodiment.

These boxes 321, 322, 323
Have buffer spaces 341, 342, 343 therein and are arranged in a line along the length direction of the duct 22. Then, as in the first embodiment, the boxes 341, 342,
At the boundary between the duct 343 and the duct 22, the drone cones 361 and 3 having the same structure as the drone cone 36 of the first embodiment.
62 and 363 are provided similarly to the drone cone 36 of the first embodiment.

The sound from the speaker 301 is radiated to the box 321, but the drone cone 361 and the buffer space 3 are radiated.
The resonance frequency of the acoustic resonance system composed of 41 is set to 115 Hz, which is substantially 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 225 Hz, which is substantially the center 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 composed of the drone cone 363 and the buffer space 343 is 40 at the center of the third frequency band.
It is set to 0 Hz. Each speaker 301, 302, 30
Signals from the amplifier 28 are supplied to the respective units 3.

In this way, the deterioration of the speakers 301 to 303 and the drone cone 36 are performed as in the first embodiment.
Not only can prevent deterioration of 1 to 363, but also 80Hz
Sound is efficiently radiated into the duct 22 over the entire frequency band from 500 Hz to 500 Hz.

Next, a third embodiment is shown in FIG. Similar to the second embodiment, this embodiment also considers the frequency band of 80 Hz to 500 Hz, which is the target frequency band, into a plurality of frequency bands, and considers the three speakers 301 and 302 to share the respective frequency bands. , 303, but the boxes are denoted by reference numerals 3211, 3221, 32.
Four are provided as shown by 31,3241. These boxes 3211 to 3241 are arranged adjacent to each other along the length direction of the duct 22.

The speaker 301 is installed in the box 32.
The buffer spaces 3411 of 11 and the buffer space 3421 of the box 3221 are attached to the boundary between the boxes 3211 and 3221 so that sound can be emitted. Similarly, the speaker 302 includes a buffer space 3421 of the box 3221 and a buffer space 343 of the box 3231.
Both boxes 322 so that sound can be emitted to both
It is attached to the boundary portion of 1,3231. Further, the speaker 303 is provided in the buffer space 3 of the box 3231.
Both boxes 3231, 32 are arranged so that sound can be radiated to both 431 and the buffer space 3441 of the box 3241.
It is attached to the boundary portion of 41. In addition, the boxes 3211, 3221, 3231 and 3241 and the duct 22.
At the boundary portion between the and the drone cones 3611, 3621, 3631, 3 similar to the drone cone 36 of the first embodiment.
641 are provided respectively.

In this example, the target frequency band is divided into four frequency bands, that is, the first to fourth frequency bands, and the drone cone 3 is provided in each frequency band.
611, 3621, 3631, and 3641 are configured to correspond to each other. 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 becomes 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 resonance frequency so 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 and the drone cone 364 of the box 3241 are set to be substantially equal to the center frequency of the frequency band.
The acoustic resonance system of 1 has a resonance frequency 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 the target frequency band 80 Hz to 500 Hz.

In this embodiment, four boxes 3 are used.
211 to 3241 and three speakers 301 to 303
However, the number of speakers used and the number of boxes used 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 space larger than the number of speakers used.

In the second or third embodiment, the boxes 321 to 323 or 3211 to 3241 are dispersed and attached in the length direction of the duct. It is generally difficult to process the duct 22 so that such attachment can be performed, and in order to attach each box 321 to 323 or 3211 to 3241, the duct 22 is required.
Since the length must be a certain length or more, it is not possible to downsize the entire device. 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 side by side, the impulse response of the entire speaker device becomes long. The problem that the impulse response becomes long is eventually solved by providing an anti-phase signal generation filter (not shown) with the inverse characteristic of the impulse response, but the inverse characteristic for a long impulse response is generally Since it is more complicated than that for a short impulse response, the inverse characteristic signal generating filter becomes large in size. The large scale of the filter referred to here means, for example, FI.
This means that the number of taps of the filter increases in the R filter and the filter order increases in the IIR filter. These points have been improved in Figs.
It is a fourth embodiment shown in FIG. FIG. 4 is a sectional view taken along the line AA of FIG.

In the fourth embodiment, each drone cone 361 is
Sounds radiated from 1,3621,3631,3641 are radiated by being concentrated on almost one point of the duct 22 through the nozzle-shaped duct 40. By doing so, the acoustic path lengths from the drone cones 3611 to 3641 to the detection microphone (not shown) become substantially equal, and the impulse response of the entire speaker device can be shortened. Further, in order to attach such a duct 40 to the duct 22, it suffices that the duct 22 be processed so that only the narrow mouth portion of the duct 40 is attached. Further, it is not necessary to lengthen the duct 22.

In the fourth embodiment, the nozzle-shaped duct 40 is used.
However, the improvement of this point is as shown in FIG. 6 and FIG.
9 is a fifth embodiment shown in FIG. 8 and a sixth embodiment shown in FIG.

In the fifth embodiment, the boxes 3211 to 3241 are arranged along the peripheral edge of the duct 22. In this way, the length of the duct 22 can be kept short without using the nozzle-shaped duct 40. Also, the impulse response of the entire speaker device does not become long. However, with such a configuration, since the buffer space 3441 that radiates the highest sound and the buffer space 3411 that radiates the lowest sound are adjacent to each other, the sounds of both buffer spaces can be propagated to the respective buffer spaces. In order to prevent this, a partition wall 42 completely separates the boxes 3441 and 3411.

In the sixth embodiment shown in FIG. 8, the box 3
The resonance frequencies of the acoustic resonance system including 211 to 3241 and the drone cones 3611 to 3641 provided therein may be the same for all four boxes 3211 to 3241, or may be different for each box. Also, the opposing boxes may be the same. When the resonance frequencies are the same for all four boxes, or the same for opposite boxes, the output sound pressure output from each box is added, and as a result, the output efficiency can be increased. .

[0033]

As described above, according to the present invention, the loudspeaker is installed in the space provided so as to communicate with the passage of high temperature or corrosive gas, and the loudspeaker is installed in the space with respect to the passage. Heat resistant to a state of airtightly shut off,
Since the corrosion-resistant drone cone is provided, the speaker is not directly exposed to the 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.

Further, in such a speaker device,
By providing a plurality of acoustic resonance systems having different resonance frequencies, each of which includes a buffer space and a drone cone, sound can be efficiently radiated over the entire target frequency band. Further, in the speaker device having the plurality of buffer spaces, the sound of the speaker is emitted to the gas passage through the nozzle duct, or the plurality of buffer spaces are provided along the periphery of the gas passage. The speaker device can be easily attached to the gas passage, the entire device can be downsized, and the impulse response of the entire speaker device can be shortened. When used in the device, the antiphase signal generation filter does not have to be large-scaled.

[Brief description of drawings]

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

FIG. 2 is a schematic configuration diagram of the second embodiment.

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

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

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

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

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

FIG. 8 is a sectional view of the sixth 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 generating filter (anti-phase signal generating means) 30 301 to 303 speaker 34 341 to 343 3411 to 3441 buffer space 36 361 to 363 3611 to 3641 drone cone

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area H04R 1/40 310

Claims (6)

[Claims] 1. A space provided in a state of communicating with a passage of high temperature or corrosive gas, a speaker provided in a state of expanding into this space, and an airtight cutoff of the speaker from the passage in the space. A speaker device comprising: a heat-resistant and corrosion-resistant drone cone provided in a ready state. 2. A plurality of spaces provided in a state of communicating with a passage of high temperature or corrosive gas, a plurality of speakers provided in a state of expanding into these spaces, and each of the speakers in each of the spaces having the passage. Heat-resistant and corrosion-resistant plurality of drone cones provided in a state of airtightly blocking against, from at least one space of the plurality of spaces and the drone cone provided in this space A speaker device, wherein a resonance frequency of the acoustic resonance system is different from a resonance frequency of an acoustic resonance system including at least another space and the drone cone provided in the other space. 3. A plurality of spaces provided in a state in which they are in communication with a passage of a high temperature or corrosive gas and adjacent to each other, a plurality of speakers provided at each boundary of these spaces, and in each of the above spaces. A plurality of heat-resistant and corrosion-resistant drone cones provided to hermetically shut off the speakers from the passage, and at least one space of the plurality of spaces and the space provided therein. A speaker device, wherein a resonance frequency of an acoustic resonance system including a drone cone is different from a resonance frequency of an acoustic resonance system including at least another space and the drone cone provided therein. 4. The speaker device according to claim 2 or 3, wherein each of the spaces is provided so as to communicate with the gas passage through a nozzle-shaped duct having a narrow mouth portion and a wide mouth portion. A speaker device in which a narrow mouth portion of the duct is attached to the passage side and a wide mouth portion is attached to the space side. 5. The speaker device according to claim 2 or 3, wherein the plurality of spaces are provided along a peripheral portion of the gas passage. 6. The speaker device according to claim 1,
A silencer characterized by supplying a signal from a means for generating a signal having a phase opposite to that of the noise generated in the gas passage.