FI86630B - Aeration device - Google Patents

Description

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AIR CONDITIONING - LUFTNINGSANORDNING

The present invention relates to an aerator device for, for example, oxygen-poor water bodies or wastewater treatment plants, which aerator device consists of a propeller rotating below the water surface, the downstream of which is driven by a drive device, and an air duct through which air enters the propeller , that the air supplied to the water is discharged from the trailing edge of the blades of a rotating propeller and the propeller blades of which are hollow and the trailing edges of the wings have gaps.

There are situations where oxygen in the air has to be dissolved in water, for example in the aeration stages of sewage treatment plants and industrial wastewater treatment plants, in oxygen-poor lakes and in fish farms.

There are mainly two requirements for the aerator: - oxidizing power - mixing power

The oxidizing power is expressed in kg 02 / kWh, which is the amount of oxygen dissolved in water per kilowatt hour used. Energy is needed for the aerator and compressor. There are also aerators where energy is needed only for either the aerator or the compressor. Aerators are energy-intensive, which is why oxidizing power has a large economic impact.

A good aerator also requires good mixing power. This means that the oxygen situation in the pool is made homogeneous by means of mixing with the least possible mixing power, which also improves energy economy. The mixing also prevents harmful sludge settling in the aeration tank. Appropriate mixing also improves the oxidation efficiency.

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Devices such as the subject of the invention are known e.g. U.S. Patent 3,846,516 and CH Patent 637,031. poor efficiency as well as a large bubble size which impairs the oxidizing power.

The object of the invention is to provide a new type, efficient and cost-effective aerator device, by means of which the disadvantages of the prior art are avoided. The aerator device according to the invention is characterized in that the height of the gap is 0.2-0.5 mm and the thickness of the leading edge of the wing, at least at the gap, is 1.0-1.5 mm and that the ratio of the length of the gap to the length of the leading edge is 0.4-0 , 6 and that the ratio of the distance of the outermost point in the radial direction of the gap from the outer circumference of the propeller to the length of the trailing edge is 0.1-0.25, whereby the air does not enter the end vortex of the wing.

The invention achieves a very good mixing with water and air, because the rotating propeller and the air discharged from the vanes mix water and air very efficiently. When the height of the gap is only about 0.2-0.5 mm, sufficiently small air bubbles are obtained which are advantageous for oxygen dissolution. In addition, the solution according to the invention avoids e.g. the entry of air into the wing vortex, which also improves the oxidation efficiency.

The invention will now be described by way of example with reference to the accompanying drawings, in which

Figure 1 shows a schematic view of an aerator device.

Figure 2 shows a section taken along the line II-II in Figure 1.

Figure 3 shows a section taken along the line III-III in Figure 2.

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Figure 4 shows three different wing profiles.

Figure 5 shows the trailing edge of the wing, showing narrow air gaps.

Figure 6 shows an aerator device mounted on a support base and in an inclined position.

Figure 7 shows an aerator device with a nozzle.

Figure 8 shows an application with a nozzle and a support base.

Figure 9 shows an aerator device in which the drive device is located above the water surface.

The aerator device consists of a rotating propeller 1, which is rotated by a drive device 2, and an air pipe 3, through which air enters the water. The air pipe 3 communicates with the propeller 1 so that the air supplied to the water is discharged from the trailing edge 10 of the rotor propeller blades 4. Air is pumped along the pipe 3 inside the propeller 1 by means of a compressor through the air housing 5 and the hollow shaft 6. The blades 4 of the propeller 1 are hollow and the leading edges 10 of the vanes have elongated narrow slits 7. The height s of the slot is about 0.2-0.5 mm and the thickness a of the leading edge 10 of the wing is about 1.0-1.5 mm. In the embodiment shown in Fig. 6, the axis of the aerator propeller is arranged by means of a support base 8 at an angle of about 35 ° to 55 ° with respect to the vertical axis. Figure 7 shows a support base according to another embodiment. There is also an annular nozzle 9 around the propeller 1, which improves the flow.

The length 1 of the gap s of the leading edge of the wing may be the same as the length c of the leading edge of the wing, but it is more preferable to dimension such that 1 / c is about 0.4-0.6. The dimension b can be 0, but is 4

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more preferred if it is about 10-25% of dimension c, so that air does not enter the end vortex of the wing.

The number of wings can be 1 or more, but it is advantageous from the point of view of air distribution if it is quite high, i.e. about 6-10. The wings may be radial or, as in Figure 2, obliquely obliquely. They can also be curved. The profile of the wing may be as in Figure 3 or it may be one of those shown in Figure 4. However, the invention is not limited to these profiles, but are presented as examples.

For strength reasons, it may be necessary to support the gap s with the brackets 11 (Fig. 5). Figure 5 is a rear view of the wing. By mounting the aerator shaft at an angle of about 35 ° -55 ° (Fig. 6), a vertical component advantageous for oxygen dissolution is obtained for the flow, but at the same time a horizontal component is obtained which provides a circulating flow in annular duct-type aeration tanks. In this case, separate flow generators are not needed at all, which saves both acquisition and energy costs.

Claims (1)

PATENT C , through which air is supplied to water, which air tube communicates with the propeller so that the air supplied to the water is discharged from the trailing edge (10) of the rotating propeller blades and the propeller blades are hollow and the wing trailing edges have slits (7), characterized in 7) the height (s) is 0,2-0,5 mm and the thickness (a) of the leading edge (10) of the wing, at least at the gap (7), is 1,0-1,5 mm and that the length (a) of the gap (7) 1) the ratio to the length (c) of the trailing edge (10) is 0.4 to 0.6 and that the ratio of the radially outer distance (b) of the slot (7) from the outer circumference of the propeller to the length (c) of the trailing edge (10) is 0.1 to 0 , 25, so that the air does not enter the end vortex of the wing 630 Luftningsanordnin för exempelvis syrefattiga vattendrag eller avloppsreningsverk, bestaende av ett skovelhjul (1) som drivs av ett drivaqqregat (2) ocer roterar under vattenytan ä to stromning ästadkoms nedät, samt av et luftn open to the ground to the ground through the ground (10) of the cross head to the ground (7), the head to the spring (7), to the spring (7) 2 to 0,5 mm and in the case of (a) with a slip (10), a spring in the spring (7), a diameter of 1,0 to 1,5 mm in the case of springs (7) ( 1) ock bakkantens (10) längd (c) är 0,4 ... 0,6 och att förhäliandet mellan avständet frän springans (7) radellt sett httersta punkt (b) till skovelns periphereri ock bakkantens (10) längd (c) is 0.1 ... 0.25, colors Iuften inte blir utsatt för virvelbild-ningen vid skovelns ända.