JPH034349Y2 - - Google Patents

Description

[Detailed explanation of the idea]

Industrial Application Field The present invention relates to an aeration device that stirs a liquid and blows gas into the liquid. Conventional technology As shown in Figure 2, conventional aeration equipment uses a plate-shaped cover to cover the rotating parts in order to prevent dangers such as foreign objects being caught in or caught in the rotating parts. Ta. Problems that the invention aims to solve: When an aeration device is driven, the rotating sound of the drive device and the sound of air being sucked resonate with the sound of the cover, increasing low-frequency noise, which has caused problems such as headaches. . Means for Solving the Problems The aeration device of the present invention has a hollow shaft provided with an air suction hole in the upper part and a stirring blade in the lower part, which is rotated by a drive device. The entire cover covering the aeration device or the portion covering the air suction hole of the hollow shaft is made of a perforated plate to reduce low frequency noise. Embodiments The present invention will be described below based on illustrated embodiments. In the figure, reference numeral 1 denotes a drive device consisting of an electric motor, a hydraulic motor, etc., and a hollow shaft 2 is connected to the drive shaft of the device 1 via a shaft coupling or directly. This hollow shaft 2 has a length that allows it to be immersed in the liquid to be stirred to a required depth, and stirring blades 3 are provided at the lower part of the hollow shaft in the liquid immersed part. Then, when the hollow shaft 2 is stirring the liquid, the air suction hole 4 for air or gas is bored so as to be located above the liquid level. Further, an air outlet 5 is formed at the lower end of the hollow shaft 2 to open into the liquid at all times during liquid stirring, and a cover 6 is provided over at least the area of the hollow shaft 2 that is immersed in the liquid. The outer circumference of the hollow shaft 2 is covered with a desired gap on the outer circumferential surface of the shaft. At least a portion of the cover 6 that covers the air suction hole 4 of the hollow shaft 2 is made into a perforated plate 6a. It is also possible to make the entire cover a perforated plate, and the shape of the holes,
The size can be freely designed. In the apparatus constructed as described above, first, when the driving device 1 installed above the liquid level is driven, the stirring blade 3 installed at the lower part of the hollow shaft 2 immersed in the liquid moves through the hollow shaft 2. Rotate. The rotation of the stirring blade 3 stirs the liquid, and as the liquid is stirred, a negative pressure is generated in the liquid in the shaft direction.
Due to this negative pressure, air or gas is sucked through the air suction hole 4 provided in the cover 6 of the hollow shaft 2,
The air passes through the hollow shaft 2 and is emitted into the liquid from an air outlet provided at the lower end of the hollow shaft. This air or gas is radiated straight into the liquid in the shaft direction, and is mixed with gas and liquid and dissolved into the liquid by the stirring flow of the liquid. Furthermore, during operation of the aeration device, the motor rotation sound and air suction sound resonate with the cover 6, increasing low-frequency noise, but at least the part that covers the air suction hole 4 of the hollow shaft 2 should be made of a perforated plate. This allows air from outside to be taken in and prevents low-frequency noise. The table below shows actual measurement data for the standard structure that does not use a perforated plate for the cover and the present invention that uses a perforated plate for the cover. Measurement method: Measured with a frequency analysis sound level meter at a position 1m away from the sound source

[Table] Center frequency
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Claims (1)

[Scope of utility model registration request] In an aeration system that stirs liquid and supplies air using a hollow shaft that rotates by a drive device and has an air suction hole at the top and a stirring blade installed at the bottom of the hollow shaft, a cover that covers the aeration system is used. An aeration device characterized in that the whole or at least the portion covering the suction hole of the hollow shaft is made of a perforated plate.