JPS5813234B2 - Aeration method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aeration method that also prevents noise when using a submersible blower, particularly a roots-type blower which is difficult to muffle due to its high noise level in the low frequency range.

Recently, aeration systems in which the blower body is installed underwater for the purpose of soundproofing have come into widespread use.

However, in the case of Roots blowers, which are difficult to muffle due to the high level of noise especially in the low frequency range, due to the structure, the sound emitted from the side wall of the main body casing toward the outer circumference travels straight through the water horizontally and hits the tank wall. As a result, the sound may be emitted from the side wall of the tank, or may be transmitted to other objects connected to the tank wall, for example, in the case of an underground tank, to structures above ground.

Although forming an air layer around the inner periphery of the tank wall would have a sound dampening effect, it is structurally difficult to implement, and the current issue is how to deal with sound deadening in this case.

In order to prevent noise in an aeration system using a submersible blower as described above, the present invention forms at least one air curtain with an appropriate diameter centered around the submersible blower installed at the bottom of the aeration tank, and the curtain is connected to the blower. The air curtain was placed only on the sides of the tank and gradually diffused into bubbles as it reached the top, and the air curtain blocked the transmission of sound to the tank wall and attenuated the sound within the air curtain. The present invention relates to an aeration method characterized by the following.

To explain in detail based on the embodiment shown in the figure, 1 is a submersible blower installed at the center bottom of a circular aeration tank 2, which sucks atmospheric air through an intake pipe 3, and a discharge pipe 5 with a check valve 4 interposed in the middle. This is how the exhaust is done.

Reference numerals 6 and 7 denote aeration pipes, which are arranged at the bottom of the tank with an appropriate diameter centered on the submersible blower 1, have an appropriate number of nozzle holes, and have a distal end portion formed by bending the discharge pipe 5 into an inverted U shape. They are communicated with each other.

Thus, during operation, a double air curtain C1, C2 is formed at the outer periphery of the blower 1 by a large number of layers of bubbles ejected upward from the diffuser pipes 6, 7.

Therefore, a group of sound waves that are launched from the outer periphery of the casing of the blower 1 horizontally over the entire circumference are mainly blocked by the air curtain C1, a part of which is absorbed and muffled by the air layer formed by the curtain C1, and the remainder returns to the original direction. It is reflected by the next wave and is gradually attenuated due to mutual interference.

The sound waves slightly directed toward the water surface collide with the atmospheric layer, are reflected by the atmospheric layer, return to the water, and are attenuated and muffled within the air curtain C1 due to mutual interference with subsequent sound waves.

When the air layer of the air curtain CI is thin, some sound waves pass through the curtain C1, but are blocked by the next air curtain C2 in the same manner as described above, and are attenuated and muffled within the curtain C2.

Although the air diffuser pipes 6 and 7 in the above explanation have nozzle holes facing upward, they may have nozzle holes facing diagonally as appropriate depending on the case.It is more reliable if the air diffuser pipes are multiple, but even a single air diffuser will not serve the purpose. It is achievable.

Furthermore, depending on the case, the diffuser pipes 6 and 7 may be provided with horizontal nozzle holes on the inside to form a horizontal air curtain parallel to the bottom of the tank, thereby blocking reflected sound toward the bottom of the tank and making it even more effective. It is.

In addition, the thickness of each part of the air curtains C1 and C2 can be made substantially equal by connecting the discharge pipes to the diffuser pipes 6 and 7 at a plurality of locations as appropriate, instead of at one location.

As described in detail above, according to the method of the present invention, all the sound that conventionally propagated horizontally from the body wall of the blower body to the tank wall is blocked by the air curtain and partially attenuated, and the reflected sound is The sound is gradually attenuated and muffled by mutual interference with the sound waves.

A portion of the sound wave that escapes toward the water surface is also reflected at that portion and returns to the water, and is gradually damped and attenuated by mutual interference with the next sound wave within the air curtain.

Therefore, there is no need for special equipment for noise reduction.
A simple configuration that uses air bubbles for aeration, which is originally necessary, to form an air curtain can produce a sound-silencing effect.Since the sound is silenced by an air layer, it is not limited to low-frequency noise, but also high-frequency noise. Since the effect can be obtained, there is no need to be limited to one type of blower.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, with FIG. 1 being a sectional structural view and FIG. 2 being a plan view. In the figure, 1 is a submersible blower, 2 is an aeration tank, 5 is a discharge pipe,
6 and 7 are aeration pipes, and C1 and C2 are air curtains.

Claims (1)

[Scope of Claims] 1. In a device in which aeration is performed by a submersible blower installed at the bottom of the aeration tank, at least one annular air curtain having an appropriate diameter is formed with the submersible blower as the center, and the curtain is connected to the blower sounding section. An aeration method characterized in that the aeration is carried out only on the sides and gradually diffuses as it goes upward, so that it appears to form bubbles. 2. The aeration method according to claim 1, wherein the air curtain is formed in multiple layers with appropriately different diameters.