JP2000130145A - Active silencing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect an acoustic equipment from the environment as quickly as possible by installing an interrupting tool which can be selected into a first state that gas flowing in an acoustic wave propagation path flows and a second state that the flow is interrupted between the acoustic wave propagation path and an arranging part of the acoustic equipment on a connection path. SOLUTION: In a duct 5 as a connection path between an active silencing device 1 and an exhaust pipe 4, an interrupting damper 6 to be an interrupting tool for interrupting a speaker 13 from exhaust gas 3 flowing within the exhaust pipe 4 is installed. The interrupting damper 6 can be opened and closed by an automatic operation or a means operation, rotates around an axis of ordinate 10 and can be switched into a first state that gas flowing in an acoustic wave propagation path flows and a second state that the flow is interrupted between the acoustic wave propagation path and a speaker 13 arranging part. Namely, when an abnormality is generated in a cooling fan 15, the interrupting damper 6 is automatically operated to the second state and the duct 5 is interrupted from exhaust gas flowing in the exhaust pipe 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active silencer provided for the purpose of silencing an exhaust gas passage provided with a heat engine such as a gas engine or a gas turbine on an upstream side.

[0002]

2. Description of the Related Art As a conventional example of the above-mentioned active silencer, there is one disclosed in Japanese Patent Publication No. 8-23755. As disclosed in this publication, the active noise reduction device includes an acoustic device acoustically connected to a sound wave propagation path via a connection path. Such an acoustic device is a first sensor microphone that is provided on the upstream side of the propagation path and extracts information on a sound wave propagated from a noise source, and is provided on the downstream side of the first sensor microphone, and performs interference silencing on the propagated sound wave. A speaker that artificially generates an additional sound wave, and a second sensor microphone that is provided downstream of the speaker and that evaluates a muffling effect.

[0003] Such interference silencing is referred to as active silencing, and is a concept for passive silencing performed by absorbing a sound absorbing material such as a porous material lined in a pipe.
Although the active silencer can be used in combination with the passive silencer, it is particularly effective for silencing low-frequency noise, such as a sound absorbing material, that easily passes through the passive silencer (for example, Japanese Patent Laid-Open No. 6-129227). Reference).

Conventionally, when an active silencer is installed in a gas engine, a gas turbine, or the like, the active silencer is provided so as to be exposed to high-temperature and high-humidity exhaust gas in an exhaust pipe.

[0005]

SUMMARY OF THE INVENTION However, high temperature
High-humidity exhaust gas may be condensed on the connection path to the active silencer due to a temperature difference between the connection path and the inside of the exhaust pipe. Here, since acoustic devices such as sensor microphones and speakers are electronic devices, if water droplets adhere thereto, reliability and durability are significantly reduced. Therefore, when the performance deteriorates due to long-time use in the above environment, it is necessary to replace the sensor microphone, the speaker, and the like. Further, the performance of the speaker or the like may be reduced due to a cooling system (such as a cooling fan) for cooling the speaker so that the speaker can maintain appropriate performance even with high-temperature and high-humidity exhaust gas. . In this case, it is necessary to repair the failed part of the cooling system.

[0006] Although many gas engines, gas turbines, and the like are operated continuously, as described above, the exhaust pipe and the arrangement of the acoustic equipment are conventionally connected and connected as described above. From the viewpoint of work safety, it is necessary to stop the operation of the gas engine, gas turbine, and the like when performing the above-described replacement work or repair work. In addition, complaints about noise pollution have been frequent in recent years, and urgent work is required. An object of the present invention is to provide a gas engine,
It is an object of the present invention to provide an active silencer capable of replacing a sensor microphone, a speaker, and the like or repairing a cooling system while an operation of a gas turbine or the like is continued.

The above-mentioned cooling system is installed to enable the speaker to maintain an appropriate performance even with high-temperature and high-humidity exhaust gas. When the abnormality occurs, the speaker may be damaged unless the speaker is immediately protected from the high-temperature and high-humidity fluid in the exhaust pipe. Therefore, another object of the present invention is to quickly protect an audio device from a bad environment such as a high temperature and a high humidity when the cooling system causes a failure or the like and the audio device such as a speaker is placed in a poor environment. An object of the present invention is to provide an active silencer capable of performing the above.

[0008]

In order to achieve the above object, the present invention comprises an acoustic device acoustically connected via a connection path to a sound wave propagation path connected to a noise source on the upstream side. In the active silencer, the connection path can be selected between a first state in which gas flowing through the sound wave propagation path flows and a second state in which gas flowing through the sound wave propagation path is cut off, between the sound wave propagation path and the arrangement portion of the acoustic device. It is characterized in that a suitable blocking device is installed.

[0009] By arranging such a blocking member, it is possible to cut off the space between the exhaust pipe and the locating portion of the acoustic equipment. Therefore, an operator on the active silencer side can operate the gas engine, the gas turbine, etc. Even in the middle, operations such as maintenance of audio equipment and repair of cooling system can be performed in a safe environment without being bothered by high-temperature and high-humidity exhaust gas generated during operation and flowing through the exhaust pipe. . Therefore, maintenance work and repair work can be performed while the operation of the heat engine such as the gas engine and the gas turbine is continued, and a decrease in the work efficiency of the heat engine can be suppressed even when the active silencer is abnormal. it can. In addition, the work can proceed smoothly from the reduction of the psychological burden based on the safety of the work environment, and the time during which the active silencer does not operate can be minimized. As a result, an active silencer suitable as a measure against complaints against noise pollution could be obtained.

[0010] In addition to the above configuration, the present invention further comprises an abnormality detecting mechanism for detecting an abnormal operation of the active silencer, and the blocking member in the first state during the normal silencing operation includes: Providing a breaker operation control mechanism for setting the state to the second state when an abnormality is detected by the abnormality detection mechanism is further advantageous in the following points.

With this configuration, if the audio equipment does not operate normally due to, for example, a failure in the cooling system or an increase in temperature or humidity due to dew condensation on the connection path, such an abnormal operation is recognized as abnormal. The detection mechanism detects.
Based on the detected content, the breaker operation control mechanism is automatically operated to switch the breaker to the second state. Therefore, when an abnormality such as a decrease in the output of a speaker that is an acoustic device occurs, the breaker switched to the second state by the breaker operation control mechanism causes the active silencer to remove the gas flowing through the sound wave propagation path from the gas. Since it is possible to shut off, the acoustic equipment such as a speaker is protected from high-temperature and high-humidity gas, and damage to the acoustic equipment can be prevented. In addition, it is also possible to effectively prevent the occurrence of secondary damage such as deterioration or damage of each part of the active silencer to the one having no abnormality. If the shutoff device is configured to be able to be automatically opened and closed by remote control, the shutoff device can be automatically closed and the communication connection between the active silencer and the exhaust pipe can be cut off. It is possible to start immediately, and it is possible to quickly protect each part of the active silencer from an unfavorable environment such as high temperature and high humidity.

In order to determine that an abnormality has occurred in the active silencer, the temperature or humidity at the front portion (on the sound wave propagation path side) of an acoustic device such as a speaker may be determined as described in claim 3 or 4. It is preferable to use as a reference. If any of these is used as a criterion for detecting an abnormality, the loudspeaker and the like are protected from a high-temperature or high-humidity fluid in the exhaust pipe, and the damage is effectively prevented by responding promptly to an abnormality such as a failure in the cooling system. .

In the conventional active silencer, there has been no consideration given to the maintenance of the active silencer in relation to the continuous operation of the engine and the turbine.
On the other hand, according to the present invention, the durability of a sensor microphone, a speaker, and the like is improved by promptly responding to the detection of an abnormality of the active noise reduction device and protecting the device. The overall durability can also be improved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an active silencer according to the present invention will be described below with reference to the drawings. FIG.
1 schematically shows the entire structure of the active silencer 1. Exhaust gas from the gas engine 2 (corresponding to a noise source) passes through an exhaust pipe (corresponding to a sound wave propagation path) 4 in a direction indicated by an arrow 3, and at this time, sound waves propagated from the engine 2 are also transmitted as noise.

A duct 5 from the exhaust pipe 4 (an example of a connection path)
The acoustic equipment of the active silencer 1 is installed in the duct 5. The acoustic device includes a speaker 13 in the exhaust pipe 4 as a sound wave propagation path from the gas engine 2.
A first sensor microphone 11 provided upstream of the sensor for detecting information on the propagated sound wave, for example, characteristics such as phase and sound pressure (amplitude), processes the detected information, and has the same phase as the propagated sound wave in opposite phase. A control device 12 for creating information (electric signal or the like) representing an additional sound wave of pressure, the speaker 13 for radiating the additional sound wave to mute the interference of the propagating sound wave, and provided on the downstream side of the speaker 13 to provide an effect of interference muffling. And a cooling fan 15 that cools the speaker 13 with outside air.

The first sensor microphone 11 comprises a pair of a normally used microphone 11a and a backup microphone 11b. In normal times, the microphone 11a is used and is connected to the control device 12 via the automatic changeover switch 23. However, when a failure or the like occurs, the failure detection panel 9 detects the failure and activates the automatic changeover switch 23. The microphone is automatically switched to the backup microphone 11b via the backup microphone 11b. Second
The sensor microphone 14 also includes a pair of a normally used microphone 14a and a backup microphone 14b. In normal times, the microphone 14a is used and is connected to the control device 12 via the automatic changeover switch 24. However, if a failure or the like occurs, the failure detection panel 9 detects the failure and activates the automatic changeover switch 24. The microphone is automatically switched to the backup microphone 14b.

In the present invention, as shown in FIG. 2, a duct 5 serving as a connection path between the active silencer 1 and the exhaust pipe 4 is provided with a shut-off damper for shutting off the speaker 13 from exhaust gas flowing through the exhaust pipe 4. (An example of a blocking device) 6 is provided.
The cut-off damper 6 is configured to be able to open and close both automatically and manually. The breaking damper 6 has a vertical axis 1
It turns around 0, and the gas flows through the sound wave propagation path between the sound wave propagation path and the speaker 13 in a first state (dashed line) where the gas flows and a second state (solid line) where the gas is cut off. It is configured to be switchable. Hereinafter, the operation of the cut-off damper 6 will be described with reference to FIGS.

FIG. 3 is a flowchart for explaining the operation of the shut-off damper 6 when an abnormality occurs in the cooling fan 15. When an abnormality occurs in the cooling fan 15, the shut-off damper 6 is set to the second
The state is automatically operated to cut off the duct 5 from exhaust gas flowing through the exhaust pipe 3. Here, regarding the abnormality detection, a first fan installed in a cooling fan 15 for cooling the speaker 13 is used.
The abnormality detection sensor 7 detects an abnormality (step # 1)
0). In order to judge an abnormal situation, the cooling fan 15
Can be used as a reference when the detected temperature of the first abnormality detection sensor (an example of abnormality detection means) 7 becomes higher than a predetermined value due to the abnormal operation of the sensor. In this case, the first abnormality detection sensor 7 is configured as a temperature sensor.

An abnormal situation is transmitted to a failure detection board 9 connected to the first abnormality detection sensor 7. Then, the failure detection board 9
Functions as a breaker operation control mechanism, and
Opening command signal to automatically shut off the
(When shutting off, a signal indicating the opening degree of 0 ° is applied). The abnormal situation is also transmitted from the failure detection panel 9 to notification means (not shown) such as an alarm lamp and an alarm buzzer, so that the observer can recognize the occurrence of the abnormal situation.
In response to the opening command signal, the cut-off damper 6 is switched from the first state at the time of normal opening to the second state at the time of abnormal shut-off (step # 20). As a result, the active silencer 1 is cut off from the exhaust gas flowing through the exhaust pipe 4, and the active silencer 1
Sound equipment is quickly protected. High temperature (about 300 ° C.) from the exhaust pipe 4 by shutting off the shutoff damper 6
Gas engine 2 without bothersome exhaust gas
It is possible to repair the cooling fan 15 without stopping the operation of the cooling fan 15 (step # 30). When the repair work is completed, the shutoff damper 6 is manually restored to the open state, that is, the first state (step # 40).

A second abnormality detection sensor 8 is provided in front of the speaker 13. Like the first abnormality detection sensor 7, the second abnormality detection sensor 8 is also connected to the failure detection board 9.
If the detected temperature becomes higher than a predetermined value due to the failure of the cooling fan 15 or if the detected humidity becomes higher than the predetermined value due to dew condensation near the speaker 13, the fact is reported to the failure detection panel 9. And the first abnormality detection sensor 7
The same processing is performed as in the case where an abnormality is detected. That is, the second abnormality detection sensor 8 is a temperature sensor or a humidity sensor.

FIG. 4 is a flow chart for explaining the operation of the cut-off damper 6 when the speaker 13 as an audio device is maintained. When performing maintenance on the speaker 13, the operator manually closes the shutoff damper 6 and switches to the second state (step # 110), and performs necessary maintenance work (step # 120). When the work is completed, the cut-off damper 6 is manually restored to the open state, that is, the first state (step # 130).

As shown in FIG. 1, third and fourth abnormality detection sensors (temperature sensors or humidity sensors) 21 and 22 are also provided in front of the first sensor microphone 11 and the second sensor microphone 14. Have been. The duct 5a, which is a connection path between the first sensor microphone 11 and the exhaust pipe 4, and the second sensor microphone 14 and the exhaust pipe 4
In the duct 5b which is a connection path between the failure detection panel 9 and the interruption dampers 6a and 6b similar to the interruption damper 6, as interruption devices.
It is installed in a connected state.

[Alternative Embodiment] In the above-described embodiment, from the viewpoint of resuming the operation of the active silencer 1 at an early stage, after the repair work and the maintenance work are completed, the operator himself manually restores the shut-off damper 6 to the open state. However, the configuration may be such that the recovery work of the cut-off damper 6 can also be performed automatically.

Further, in the above embodiment, the cut-off damper 6
Is used as an example of the blocking device, but the present invention is not limited to this, and any other device can be used.

Further, the criterion for detecting the abnormality is not limited to the temperature of the cooling fan or the temperature or humidity in front of the speaker as described in the above embodiment. For example, the value of the current flowing through the power supply circuit to the cooling fan that cools the speaker, the output voltage of the controller, the input voltage of the sensor microphone, or the comparison result between the input voltage value and the output voltage value of the power amplifier may be used. It is possible. Further, it is also possible to adopt a configuration in which a case where there is no speaker current despite a drive signal being transmitted to the speaker is determined to be abnormal.

[0026]

As described above, according to the active noise reduction device of the present invention, while maintaining the operation of a heat engine such as a gas engine or a gas turbine, the same safety as before can be secured and the cooling fan can be repaired. In addition, since operations such as maintenance of acoustic equipment can be performed quickly, it is possible to suppress a decrease in work efficiency of the heat engine even when the active silencer is abnormal.

Further, since a mechanism is provided for switching the cut-off damper to the cut-off state, which is the second state, when an abnormality is detected, the acoustic equipment is placed in an unfavorable environment such as high temperature and high humidity due to a failure of the cooling fan or the like. However, each part can be quickly protected from the environment. Therefore, each device is quickly protected from the exhaust gas of the exhaust pipe, and damage can be prevented. Further, it is also possible to effectively prevent the occurrence of secondary damage such as deterioration and damage to equipment having no abnormality.

[Brief description of the drawings]

FIG. 1 is a plan view schematically illustrating an active silencer.

FIG. 2 is an enlarged view of a main part of FIG. 1;

FIG. 3 is a flowchart for explaining the operation of the breaker when the cooling fan is abnormal.

FIG. 4 is a flowchart illustrating the operation of the breaker during speaker maintenance.

[Description of Signs] 1 Active silencer 2 Noise source 5, 5a, 5b Connection path 6, 6a, 6b Circuit breaker 7, 8 Abnormality detection mechanism 9 Circuit breaker operation control mechanism 11, 13, 14 Audio equipment

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F16L 55/04 F16L 55/04 G10K 11/178 F02B 43/00 A // F02B 43/00 G10K 11/16 H (72 ) Inventor Junji Yoshida 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka F-term in Osaka Gas Co., Ltd. (reference) 3G004 AA06 CA12 DA21 DA24 DA25 EA01 EA06 3H025 CA01 CB02 5D061 FF02

Claims (4)

[Claims] 1. An active silencer comprising an acoustic device acoustically connected via a connection path to a sound propagation path connected to a noise source on the upstream side, wherein the connection path includes a sound propagation path and the sound transmission path. An active device characterized in that a shutoff device that can be selected between a first state in which gas flowing through a sound wave propagation path circulates and a second state in which gas flowing through the acoustic wave propagation path is interrupted is provided between the arranging part and the acoustic device. Silencer. 2. An apparatus for detecting a malfunction of an active silencer, comprising:
2. The active silencer according to claim 1, further comprising a breaker operation control mechanism that sets the breaker in the state to the second state when an abnormality is detected by the abnormality detection mechanism. 3. The active noise reduction device according to claim 2, wherein the abnormality detection mechanism uses a temperature on a sound wave propagation path side of the audio equipment for abnormality detection. 4. The active noise reduction device according to claim 2, wherein the abnormality detection mechanism uses humidity on the sound wave propagation path side of the audio equipment for abnormality detection.