JPH08309285A - Ultra-low frequency sound decreasing device for vibration sieve - Google Patents

Abstract

PURPOSE: To prevent noise by approximately vertically bisecting the internal space, exclusive of an aperture for ejecting earth and sand, etc., of a vibration sieve for sieving the earth and sand to be ejected by a mud water shielding method by grain sizes and providing this device with an enclosure for hermetically enclosing the vibration sieve with a small capacity. CONSTITUTION: The vibration sieve 1 is provided with the enclosure 10 for hermetically enclosing the vibration sieve 1 and a mud water bucket 4 exclusive of a duct 12 as the aperture of the sieve. The enclosure 10 consists of a ceiling 11 and side walls and the net-like sieving surface 1' vibrated by the operation of an exciter 2 vertically bisects the internal space, thereby reducing the capacity. In case the sieving surface 1' is vibrated by operation of the vibration sieve 1, a positive pressure airspace and negative pressure airspace are generated always above and below apart with the sieving surface 1' in such a manner that the positive and negative are reversed, by which both airspaces are negated with each other and the vibration noises are decreased. The vibration sounds of the vibrating sieve leaking from the enclosure are picked up by a microphone 21 and the sound waves of the opposite phase from the vibration sounds are outputted from a speaker 28 to the vibration sounds.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration sieving ultra-low frequency sound reducing device, and more particularly to an ultra-low frequency sound generated from a vibrating screen used for sieving the sediment to be carried out in the muddy water shield method according to particle size. It relates to a device for reducing noise to prevent noise.

[0002]

2. Description of the Related Art Ultra-low frequency sound generated during operation of a vibrating screen causes harmful effects such as rattling bran and window glass in a surrounding house. Therefore, sound insulation that surrounds the vibrating screen with a building or soundproof box has been used. Sound absorption measures are taken.

[0003]

However, in such a building or soundproof box, there is no versatility with respect to various models and arrangements of the vibrating sieve, and ultra-low frequency sound leaks from a gap such as an outflow section of earth and sand. It is not a noise prevention measure.

Further, a control device has been proposed which operates two vibrating screens so that the vibrations are in opposite phases to each other to muffle the sound. However, in this control device, it is necessary to prepare a plurality of vibrating screens of the same model. It cannot be applied to one vibrating sieve, and there is a problem in that the arrangement mode is extremely limited, for example, the vibrating sieves are brought close to each other, and the range and direction in which noise can be obtained are limited.

The present invention has been made in view of the above problems, and an object of the present invention is to apply a single unit to various vibrating screens one by one, and to improve the noise prevention effect. To provide a reduction device.

[0006]

The ultra low frequency sound reducing apparatus for a vibrating screen according to the present invention has only an opening for carrying out earth and sand as a means for achieving the above-mentioned object and has a sieving surface. It includes an enclosure that divides the internal space into upper and lower parts and hermetically surrounds the vibrating sieve in a small volume.

Here, the opening for carrying out the earth and sand and the like is a portion for connecting the carry-out port of the earth and sand and the like in the vibrating screen to the outside of the enclosure. It should be noted that the earth and sand loading entrance of the vibrating screen, which is easier to perform sound insulation compared to the loading and unloading entrance of earth and sand, surrounds the building for sound insulation.

The small volume means to make the enclosure as compact as possible without making the enclosure complicated.

Further, in the present invention, a control device for picking up a vibration sound of the vibrating sieve leaking from the enclosure through the opening with a microphone and outputting a sound wave having a phase opposite to the vibration sound from the speaker to the vibration sound. Can be further attached.

Here, the vibrating sound is a super low frequency sound generated by the vibration of the sieving surface.

Further, the control device is a system that causes the sound waves to interfere with each other and silences them.

Further, according to the present invention, a ceiling whose height can be adjusted can be provided in the enclosure.

Furthermore, in the present invention, the control device may be provided with a monitor means for monitoring and correcting the sound wave.

[0014]

According to the present invention, the positive pressure space area to be pressurized and the negative pressure space area to be relatively decompressed, which are generated by the vibration of the sieving surface of the vibrating screen, separate the sieving surfaces in the enclosure. The positive and negative are generated upside down and cancel each other out.

Further, if a control device is installed, the vibration sound that cannot be erased by the enclosure can be attenuated by interfering with the sound wave of the opposite phase.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an explanatory view schematically showing an infrasound reduction device for a vibrating screen according to the present invention. This device includes a vibrating sieve 1 and an enclosure 10 that hermetically surrounds a mud bucket 4 leaving a duct 12 as an opening, and attenuates low-frequency vibration sound of the vibrating sieve 1 leaking from the enclosure 10 via the duct 12. The control device 20 for erasing is combined with the enclosure 10.

The enclosure 10 has an H-shaped steel frame 13 and an iron plate so that the net-like sieving surface 1'vibrated by the operation of the vibrator 2 comes to a position that bisects the inner space and has a small volume as much as possible. It is composed of a ceiling 11 and four side walls joined together. The material of the enclosure 10 is not limited to an iron plate as long as it does not transmit sound waves to the outside.

As shown in FIG. 2, the ceiling 11 has a side frame portion 11 'which partially overlaps with the side wall and is supported by being bolted to the frame 13, and the height can be adjusted by shifting the bolt fastening portion. To be done.

The duct 12 is provided on the side wall so as to surround the earth and sand carry-out port 3 of the vibrating sieve 1, and the earth and sand remaining on the sieving surface 1'is carried out from the carry-out port 3 to the residual soil recovery tank 5 installed outside the enclosure 10. The muddy water that has been spilled and has been sifted from the sieving surface 1 ′ is received in the bucket 4. Note that the unillustrated earth and sand carry-in port penetrates the side wall airtightly.

On the other hand, the control device 20 has a microphone 2 installed on a support so as to face the duct 12 with a slight distance.
1, the speaker 28 provided above the duct 12, the filter 22 and the AD converter 23, and the microphone 2
1 and a computer 24 connected to a speaker 28 via a DA converter 25, a filter 26 and an amplifier 27. The number of speakers 28 installed is desired.

When the vibrating sieve 1 is activated and the sieving surface 1'vibrates, a positive pressure space area where pressure is applied and a negative pressure space area where pressure is relatively reduced are generated, and the vibration sound changes momentarily and momentarily. Will be the cause of However, within enclosure 10,
Since the sieving surface 1 ′ bisects the internal space, and the enclosure 10 surrounds the vibrating sieve 1 compactly, the positive pressure area and the negative pressure air area are always upside down with the sieving surface 1 ′ separated. Occur and cancel each other out. Therefore, the sound pressure is reduced and the generated vibration noise is significantly reduced.

The vibration sound that cannot be erased leaks to the outside of the enclosure 10 from the duct 12 which is set as a leakage path in advance, and the vibration sound is picked up by the microphone 21. Microphone 21
A predetermined low frequency region that becomes noise is extracted from the sound wave signal from the filter 22 by the filter 22, converted into a digital signal by the AD converter 23, and input to the computer 24. The computer 24 analyzes the phase data and the like of the input signal and generates and outputs a sound wave signal having a phase opposite thereto. This output signal is converted into an analog signal by the DA converter 25, noise is eliminated by the filter 26, then amplified by the amplifier 27 to an energy level similar to the vibration sound, and then the vibration sound is transmitted through the speaker 28. It is emitted as an output sound of opposite phase to. As a result, the vibration sound interferes with the output sound and is attenuated.

Further, in order to surely dampen the vibration sound that slightly changes due to the load of the sieving surface 1 ', the control device 20 includes a microphone 31 for picking up an output sound, with a filter 32 and an AD converter 33 interposed. A monitor means connected to the computer 24 can be attached, which means monitors the sound waves from the speaker 28 and corrects them in real time to the optimum one. As a result, a slight time lag between picking up the sound by the microphone 21 and outputting it from the speaker 28 is eliminated, but this time lag may be corrected by the computer 24.

[0025]

As described above, in the vibration sieving ultra-low frequency reducing apparatus according to the present invention, the positive pressure space region and the negative pressure generated by the vibration of the sieving surface can be applied to the vibrating screens one by one. It is possible to reduce the sound pressure, which is a noise source, by canceling the space area with the internal space.

Further, if a control device including a microphone and a speaker is additionally provided, a sound wave having an opposite phase is focused on the vibration sound which is already reduced by the enclosure and leaks from the opening previously set in the enclosure as a leakage path of the vibration sound. It can be radiated to effectively dampen the vibration sound.

Furthermore, if the height of the ceiling of the enclosure can be adjusted, it can be applied to various types of vibrating screens.

Furthermore, by providing monitor means for monitoring and correcting the sound wave output from the speaker, the noise prevention effect can be further improved.

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing an infrasound reduction device for a vibrating screen according to the present invention.

FIG. 2 is a schematic view showing a manner of supporting the ceiling of the enclosure.

[Explanation of symbols]

 1 Vibrating Sieve 1'Sieving Surface 3 Carrying Out Port 10 Enclosure 11 Ceiling 12 Duct 21, 31 Microphone 24 Computer 28 Speaker

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takuji Mori 2-12-26 Konan, Minato-ku, Tokyo Tosho Engineering Co., Ltd.

Claims (4)

[Claims] 1. A sieving surface including an enclosure for airtightly enclosing a vibrating sieve in a small volume by dividing an inner space into upper and lower parts, leaving only an opening for carrying out earth and sand and the like. Ultra low frequency sound reduction device for vibrating screen. 2. A control device further comprising a microphone that picks up a vibration sound of the vibrating screen leaking from the enclosure through the opening with a microphone and outputs a sound wave having a phase opposite to the vibration sound from the speaker to the vibration sound. Item 1. The vibration screen ultra-low frequency reduction device according to Item 1. 3. The ultra-low frequency reduction device of the vibrating screen according to claim 1, wherein the enclosure has a ceiling whose height is adjustable. 4. The vibration screen ultra-low frequency sound reducing device according to claim 2, wherein the control device has a monitor means for monitoring and correcting the sound wave.