WO2016154639A2

WO2016154639A2 - Aeration device

Info

Publication number: WO2016154639A2
Application number: PCT/ZA2016/050012
Authority: WO
Inventors: Johannes Du Plessis
Original assignee: Structovate (Pty) Ltd
Priority date: 2015-03-26
Filing date: 2016-03-24
Publication date: 2016-09-29
Also published as: WO2016154639A3

Abstract

The invention provides an aeration device. The aeration device includes a circular (generally round) body and a series of open ended tubes inside the body and spaced in a frusto-conical configuration about an axis of the circular body. The invention further provides (a shaft or) a means for attaching the body coaxially to a rotating shaft. The invention produces substantially higher oxygen transfer efficiency, improved mixing ability and improved stability.

Description

Title: Aeration Device

Technical field of the invention This invention relates to an aeration device with the purpose of enhancing the mass transfer of a gas into a liquid as commonly used in municipal and industrial wastewater treatment, fish farm aquaculture, circulated water aeration in hydroponic systems, upkeep of pond water quality as well as treatment methods used in animal waste lagoons.

Background to the invention

The inventor is aware of the use of impellers to aerate suspension mixtures such as sewage water in sewage treatment plants etc.

This type of "surface" aerator acts as an agitator that causes a violent splashing of the water such that water at or just below the surface is ejected into the air. All of the splashing and ejection of the water increases the exposure of the water to air and aids in increasing the oxygen content of the water, thus enhancing the ability of the water to support aerobic bacterial activity. Surface aerators, however, are relatively inefficient in terms of the amount of oxygen they provide to the wastewater per unit of energy consumed. The churning action and the friction of the blades required substantial energy to sufficiently churn the suspension. Also, due to the unstable nature of the churned suspension the impeller often oscillates and vibrates. The reach of impellers are also limited because of the remoteness of the surface aeration impeller from the tank bottom where the biomass solids tend to settle.

The standard measure of aeration efficiency is the amount of oxygen/gas they provide to the waste liquid per unit of energy consumed. This measure is known as the Standard Aeration Efficiency (SAE). Since electric power is one of the main operating costs in aeration processes, the oxygen-transfer efficiency performance of such aerators is extremely important. It is an object of the invention to provide a device with improved aeration efficiency, liquid mixing reach and/ or stability.

General description of the invention

According to the invention there is provided an aeration device, which device includes:

a circular (generally round) body;

a series of open ended tubes inside the body and spaced in a frusto- conical configuration about an axis of the circular body; and

(a shaft or) a means for attaching the body coaxially to a rotating shaft.

The body may be any circular shape such as cylindrical with the tubes arranged within the body along the shape of a frusto-cone with the closer arranged ends of the tubes towards the lower end of the cylindrical body.

A preferred circular shape of the body may be a frusto-conically shape, with the tubes arranged complementally within and with the narrow end of the body defining the lower end, in use, of the body.

It will be appreciated that the shape of the body should be able to house the tubes and should minimise rotational friction in a liquid. The body may preferably have a smooth surface to reduce friction when rotating and may be hollow or solid.

The bottom end of the body may extend downwards in the shape of a cylinder. The cylinder may be hollow or the tubes may extend downwards up to the bottom end of the extended bottom end. It is to be appreciated that the shape of the body may be circular, parallelepipedal in cross-section or any other suitable shape. It will be appreciated that when the device is rotated about its axis with its bottom submerged in a liquid that liquid will be forced centrifugally upwards and outwards out of the tubes. As the water is expelled above the surface of the liquid it will be replaced by water being sucked up from the bottom openings of the tubes. At a sufficient rotational speed, the expelled suspension should break up into droplets which promote aeration. It will further be appreciated since the surface of the body is smooth, friction is reduced. Since the suspension is not churned stability is improved and vibration reduced. The body can also be extended downward as described above, to improve the reach. The invention also extends to the use of an aeration device as described above to aerate a liquid.

Detailed description of the invention

The invention is now described by way of example with reference to the accompanying drawings.

In the drawings:

Figure 1 shows a perspective view of an aeration device, in accordance with the invention;

Figure 2 shows a transparent perspective view of the aeration device;

Figure 3 shows a sectional side view of the device, in use, when not rotating; and Figure 4 shows a sectional side view of the device, in use, when rotating.

Figure 5 shows a sectional side view of the device with a vertical extension, in use, when rotating.

Referring now to the drawings, the aeration device, in accordance with the invention, is generally indicated by reference numeral 10. The aeration device includes a circular frusto-conically shaped tubular body 12 and a series of open ended tubes 14 inside the wall of the body and spaced in a frusto-conical configuration about an axis of the circular body. The device also includes a means for attaching the body coaxially to a rotating shaft 15 in the form of appropriately positioned bolt holes 16 for attachment to a flange. The body 10 has a smooth surface to reduce friction when rotating. The device can be extended vertically downwards 13 to extend the mixing reach.

It shall be understood that the example is provided for illustrating the invention further and to assist a person skilled in the art with understanding the invention and is not meant to be construed as unduly limiting the reasonable scope of the invention.

Claims

1 . An aeration device, which device includes:

a circular body;

a coaxial shaft or a means for attaching the body coaxially to a rotating shaft.

2. An aeration device, as claimed in Claim 1 , wherein the body has a circular shape, with the tubes arranged within the body along the shape of a frusto-cone with the closer arranged ends of the tubes towards the lower end of the cylindrical body.

3. An aeration device, as claimed in Claim 1 , wherein the body has frusto-conical shape, with the tubes arranged complementally within and with the narrow end of the body defining the lower end, in use, of the body.

4. An aeration device, as claimed in Claim 2 or Claim 3, wherein the body has a smooth surface to reduce friction when rotating.

5. An aeration device, as claimed in any one of claims 1 to 4, wherein the bottom end of the body extends downwards in the shape of a cylinder with the cylinder being hollow.

6. An aeration device, as claimed in any one of claims 1 to 4, wherein the bottom end of the body extends downwards in the shape of a cylinder with the tubes extending downwards up to the bottom end of the extended bottom end.

7. An aeration device, substantially as described herein with reference to the accompanying drawings.