JPH09308894A - Aerating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance efficiency of aeration by providing screws at an axial end side and an intermediate portion of a hollow shaft respectively and providing an air outlet at an axial end portion of the shaft to suppress vibration of the shaft and raising flow speed at a bottom of a tank to produce finer bubbles to enable the bubbles to reach deep and far. SOLUTION: A hollow shaft 2 having a length almost reaching a bottom portion of a water tank 20 is provided and a screw 3 is mounted at a bottom end of the hollow shaft 2 for stirring and aerating water. Air supplied into the hollow shaft 2 rotatively driven by a motor 1 is injected into the bottom portion of the tank through an end of the screw 3 provided at the end portion of the hollow shaft and a high speed flow of water is formed in a region at the bottom of the water tank by the rotation of the screw 3, and therefore, the air injected into the water by the high speed flow of the water is turned into fine bubbles. Vibration is induced in the long hollow shaft 2 by the rotation, but since a screw 5 for suppressing vibration is provided at an intermediate portion thereof, the vibration can be suppressed by fluid force generated by the screw 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aerator, and more particularly, to an aerator for aerating efficiently in a sewage treatment plant or a sewage treatment plant by thoroughly agitating to the bottom of a deep water tank to atomize and mix air bubbles. is there.

[0002]

2. Description of the Related Art A conventional screw type aerator is disclosed in Japanese Patent Publication No. 56-21452. In this aerator, a screw 3 is attached to the lower end of a hollow shaft 2 driven by a motor 1 as shown in FIG. 5, and the screw 3 is mounted vertically as shown in the drawing or at a predetermined inclination angle.
0, and the screw 3 is at the required water depth position. As a result, water is agitated by the screw rotated by the motor 1, and the negative pressure generated in the water area below the screw is used to inhale through the hollow shaft and release fine bubbles into the water. Aeration is performed by stirring the bottom of the water tank with the generated water flow force.

[0003]

In the aeration method using the above-mentioned conventional screw type aerator, when applied to a rectangular deep water tank as shown in FIG. 5, the water flow force generated by the rotation of the screw is Even if the air bubbles are agitated to push them to the bottom of the water tank, the flow of the water flow from the screw spreads to the surroundings and the water flow force in the downward direction decreases, and the buoyancy acting on the bubbles causes the bubbles to reach the bottom halfway. There was a problem that it floated, which reduced the flow velocity at the bottom of the aeration tank, and that the bubbles did not reach deep water. The present invention solves the problems with the above conventional aeration device, agitates with a screw at the bottom of the water tank in a rectangular deep water tank, increases the flow velocity of the water flow, sends air to the screw end, and atomizes the bubbles deeply. It is an object to provide an aeration device that can reach a long distance.

[0004]

To achieve the above object, the aeration apparatus of the present invention comprises a hollow shaft having a length reaching almost the bottom of a water tank, a screw attached to the end of the hollow shaft, and a hollow shaft. A shaft end portion of the hollow shaft which is composed of a driving means for rotating the shaft, an air feeding means for supplying air into the hollow shaft, and a screw provided in an intermediate portion of the hollow shaft for suppressing shaft vibration It is characterized by ejecting air from.

The aeration apparatus of the present invention having the above structure is
Since the hollow shaft is lengthened and the screw is operated near the bottom of the water tank and the air outlet is installed, axial vibration of the hollow shaft can be suppressed even in a rectangular deep water tank, and the flow velocity at the bottom of the water tank is fast. Moreover, since the air is blown out at a deep water level, the bubbles are made finer and can reach deeply and distantly, the contact time with water is prolonged, oxygen is well dissolved in water, and aeration efficiency is improved.

In this case, the air supply means includes an air supply blower and a pipe connecting the blower to the hollow shaft.
A valve provided in the middle of the pipe may be used, and the valve may be closed in a state where a pressure higher than atmospheric pressure is applied to the hollow shaft during anaerobic operation.

In the aeration apparatus of the present invention having the above-mentioned configuration, the aerobic operation and the anaerobic operation can be selectively operated by opening and closing the valve, and at the time of the anaerobic operation, the air pressure is set to the atmospheric pressure or more and the air supply valve is turned on. Since it is closed, the water level inside the hollow shaft drops, and even when the water inside the hollow shaft rises by centrifugal force during anaerobic operation, it does not rise much to the top. Also,
Since the hollow shaft is long, even if a small amount of air pressure is applied to lower the water surface in the hollow shaft (for example, 50 cm), air hardly exits from the screw tip.

In this case, the screw provided in the middle of the hollow shaft is the screw provided in the middle of the hollow shaft.
It is also possible to spirally wind two or more blades around a hollow shaft so that the length of the blades is higher than the height of the blades.

In the aeration apparatus of the present invention having the above structure, since the water flow is generated in the downward direction or the oblique downward direction, the reaction force acts on the hollow shaft via the screw,
Vibration of the hollow shaft can be suppressed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the aeration apparatus of the present invention will be described below with reference to the drawings. In the figure, reference numeral 20 denotes a water tank for aeration of sewage, which in the illustrated embodiment is rectangular and has a deep water depth, and the aeration device of the present invention is arranged in this water tank 20.
This aeration device is driven by a motor (electric motor) 1 directly or via a transmission mechanism 4 as shown in the figure, and is provided with a hollow shaft 2 having a length that almost reaches the bottom of the water tank.
A screw 3 for stirring and aerating water is attached to the lower end of the.

In addition, a screw 5 for suppressing shaft vibration is attached to an intermediate portion of the long hollow shaft 2, and a bearing 6 for supporting the hollow shaft is provided on a pedestal installed above the water surface. Rotatably supported. In order to transmit the rotation of the electric motor to the hollow shaft, a transmission mechanism as shown in the figure, for example, a pulley is attached to each of the motor and the hollow shaft, and a belt is stretched between the pulleys, or power is transmitted via a gear instead of the pulley. introduce.

An air supply means, that is, a blower pipe 8 is connected between the shaft end of the hollow shaft 2 and the blower 7 installed on the frame so that air is sent from the blower into the hollow shaft. Of course, a blower pipe from the blower 2 is connected to the hollow shaft via a shaft sealing device 82 as shown in FIG. And this piping,
That is, the valve 9 is provided in the middle of the blower pipe 8. The gantry 10 rotatably supports the hollow shaft 2, and further the motor 1,
Supports the blower 7 and the like.

Since the present invention is configured as described above, the air supplied from the blower 7 is supplied into the hollow shaft 2 through the air supply pipe 8 through the end of the hollow shaft 2. The air supplied into the hollow shaft 2 rotated by the motor is discharged to the tank bottom from the end of the screw 3 provided at the end of the hollow shaft near the bottom of the water tank, and the Since the rotation causes a high-speed water flow in the water area at the bottom of the aquarium,
The air discharged into the water by this high-speed water flow is atomized by the rotation of the screw. Vibration occurs in the long hollow shaft 2 due to its rotation, but since the vibration suppressing saw screw 5 is provided in the middle portion of the hollow shaft, the vibration can be suppressed by the fluid force generated by the screw 5. . In addition,
The rotation speed of the motor 1 can be reduced through an inverter or the like. As shown in FIG. 6, the vibration suppressing saw screw 5 provided in the middle portion of the hollow shaft has two blades 5
A and 5b are wound around the hollow shaft 2, and the winding length 30 (l) is longer than the height (h) of the screw. (H / l <1).

FIG. 2 shows an anaerobic operation (operation without supplying air). During anaerobic operation, air is blown slightly from the blower 7 into the hollow shaft to apply pressure to the water surface 2 inside the hollow shaft.
After lowering 1, the valve 9 is closed to keep the pressure in the hollow shaft. As described above, during the anaerobic operation, since the operation is performed with the water surface slightly lowered, there is no problem even if the water surface near the inner wall of the hollow shaft rises due to the centrifugal force of the rotation of the hollow shaft.

FIG. 3 shows details of the shaft end of the hollow shaft. The shaft sealing device has a structure in which air can be sealed during either operation because the internal pressure of the hollow shaft is high (during aerobic operation) and negative (aerobic operation).

FIG. 4 shows details of the screw portion. Since the screw rotates at a low speed, the outer diameter is made large, and the structure is such that air can be supplied also to the outer peripheral part of the screw so that air can be discharged from the outer peripheral part of the screw as much as possible.

[0017]

According to the aeration apparatus of the present invention, the hollow shaft is lengthened, the screw is operated near the bottom of the water tank, and the air outlet is installed. Therefore, even in a rectangular deep water tank, the flow velocity at the bottom of the water tank. Faster, and because the air is blown out at a deep water level, the bubbles are miniaturized, can reach deep and distant, the contact time with water is long, oxygen is well dissolved in water, and aeration efficiency is improved . Further, according to the aeration device of the present invention, during the anaerobic operation, the air pressure is made equal to or higher than the atmospheric pressure and the air supply valve is closed, so that the water level in the hollow shaft is lowered, and the water in the hollow shaft is removed during the anaerobic operation. Even if it rises due to centrifugal force, it does not go up to the top so much, and since the hollow shaft is long, even if you apply a little air pressure to lower the water surface inside the hollow shaft,
For example, 50 cm, air hardly exits from the tip of the screw, and anaerobic operation can be reliably performed. Further, according to the aeration apparatus of the present invention, since the blade is provided in the intermediate portion of the hollow shaft, the displacement of the shaft vibration can be suppressed.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of an aeration apparatus of the present invention.

FIG. 2 is a cross-sectional view showing an embodiment of the aeration apparatus of the present invention during anaerobic operation.

FIG. 3 is an explanatory view showing an air sealing device at the end of a hollow shaft.

FIG. 4 is an explanatory diagram showing a screw tip portion.

FIG. 5 is an explanatory view showing a conventional aeration device.

FIG. 6 is an explanatory diagram of a screw.

[Explanation of symbols]

 1 Motor 2 Hollow shaft 3 Screw 4 Transmission mechanism 5 Screw 6 Bearing 7 Blower 8 Blower tube 82 Shaft sealing device 9 Valve 10 Stand 20 Aeration tank

Claims (3)

[Claims] 1. A hollow shaft having a length reaching almost the bottom of a water tank, a screw attached to the end of the hollow shaft, a drive means for rotating the hollow shaft, and an air supply for supplying air into the hollow shaft. An aerating device comprising a means and a screw provided in an intermediate portion of the hollow shaft for suppressing shaft vibration, and ejecting air from a shaft end of the hollow shaft in water. 2. The air supply means is composed of a fan for air supply, a pipe connecting the blower to the hollow shaft, and a valve provided in the middle of the pipe, and the valve is used during anaerobic operation. The aeration apparatus according to claim 1, wherein the hollow shaft is closed under a pressure higher than atmospheric pressure. 3. The screw provided in the middle part of the hollow shaft comprises:
The aeration apparatus according to claim 1 or 2, wherein two or more blades are spirally wound around the hollow shaft, and the length of the blades is higher than the height of the blades.