WO1997022562A1

WO1997022562A1 - An aeration device

Info

Publication number: WO1997022562A1
Application number: PCT/AU1996/000797
Authority: WO
Inventors: David Bruce Bragg
Original assignee: Inglewood Technologies Pty. Ltd.
Priority date: 1995-12-05
Filing date: 1996-12-05
Publication date: 1997-06-26

Abstract

An aeration device (10) for use in a body of water or other liquid such as a dam, lake, effluent pond or the like which is subject to build up of algae and other polluting growths, wherein oxygen or other gaseous fluids are introduced into the water or other liquid. In a preferred embodiment, the device (10) comprises a housing (11) which is submerged in the body of water. The housing includes a first passage (12) for flow of water therethrough, and at least one second passage intersecting the first passage (12) so that a proportion of the water flowing into the first passage (12) flows through the second passage (17). The second passage (17) includes means (20, 22) for entraining air into the water flowing through the second passage (17) which then passes into the body of water. In another embodiment, the device (40) comprises a housing (41) which only has a single passage (42) for the flow of water. A number of the devices (10, 40) can be connected in series.

Description

TITLE: AN AERATION DEVICE

FIELD OF THE INVENTION

This invention relates to an aeration device. In particular, it is directed to an aeration device for use in a body of water or other liquid for introducing oxygen or other gaseous fluids into the water or other liquid.

BACKGROUND OF THE INVENTION

Commonly, bodies of liquid such as dams, lakes, effluent ponds or the like are subject to build up of algae and other polluting growths. This particularly occurs in effluent dams or ponds where large levels of nutrients can exist.

Further, in aquiculture, it is important for the growth and survival of marine life that clean air be introduced into the marine environment. However, efficient means are not readily available for this purpose.

To overcome these problems, various devices have been used for aerating the liquid to introduce oxygen. Commonly, such devices are located at the surface level of the body of liquid and include motor driven impellers which create air bubbles in the liquid. Other devices incorporate compressors for introducing compressed air into the liquid through a hose which is provided at the bottom of the body of liquid, the hose normally including a series of outlets through which the compressed air flows.

However, the above devices have not proved successful and/or require regular maintenance. In particular, the devices are inefficient in both producing dissolved oxygen and de- stratifying the liquid column. It is thus a general object of the present invention to overcome, or at least ameliorate, one or more of the above disadvantages and to provide an aeration device which enables oxygen, air, other fluids or mixtures of fluids to be introduced effectively into a body of water or other liquid.

DESCRIPTION OF THE INVENTION

According to the present invention, there is provided an aeration device, said aeration device comprising a housing adapted to be submerged in a body of liquid, said housing including a flow means to allow flow of a first fluid therethrough wherein said flow means includes entrainment means for entraining a gaseous fluid into said first fluid for subsequent introduction into said liquid.

Preferably, the entrainment means for introducing the gaseous fluid into the flow means includes means for creating a back¬ pressure in the flow means.

Preferably, means is provided for communicating the flow means with the atmosphere of the surrounding environment such that the back pressure created in the flow means draws in gaseous fluid from the atmosphere into the flow means and the first fluid flowing therethrough.

More preferably, the means for communicating the flow means with the atmosphere includes a duct which extends in use to the surface of the liquid.

Preferably, means is provided for supporting the duct above the surface level of the liquid. More preferably, such means is in the form of a float. Preferably, the flow means incorporates a venturi for creation of the back pressure to draw gaseous fluid into the flow means.

Preferably, means is provided for limiting the flow of the first fluid into the flow means. More preferably, the means comprises a jet or nozzle. Most preferably, the jet or nozzle is located upstream of the venturi.

Preferably, the duct is connected to the flow means at a position between the jet and venturi.

Preferably, means are provided for supporting the aeration device on the bottom of the lake, dam or other body of water or other liquid. More preferably, the means is a platform on which the device is supported.

Preferably, the first fluid is water or other liquid and the gaseous fluid is air or oxygen. More preferably, the first fluid is water and the gaseous fluid is air.

In one embodiment, the flow means includes a first passage for flow of a first fluid therethrough and at least one second passage intersecting said first passage so that a proportion of said first fluid flowing into said first passage flows through said second passage.

Preferably, the second passage extends at substantially 45° to the first passage which is disposed substantially horizontally in use. This angle, however, may be varied depending upon the direction of flow output required in the device. In addition, a number of second passages may be provided for communication with the first passage such that flow output occurs in a number of different directions. In a second embodiment, the flow means includes a single passage in said housing through which the first fluid flows.

Optional features of the aeration device of the present invention include:

a. An inlet coupling for coupling the flow means to a source of the first fluid. The source of the first fluid may be from a pump located, for example, on the shoreline of the body of the liquid. The source of gaseous fluid may be a compressor or blower.

b. An outlet coupling for connecting the device to a further device. The inlet and outlet couplings may be detachable. This permits the device to be used as a single unit by removing the outlet coupling and replacing it with a plug. Alternatively, a plurality of such devices may be provided to be interconnected in series and located in use, on the bottom of the lake, dam or other body of water or other liquid. For this purpose, the outlet coupling of one device is connected through a hose or the like to an inlet coupling of an adjacent device.

SPECIFIC EXAMPLES

In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate preferred embodiments of the invention wherein:-

Figure 1 illustrates in perspective view a first embodiment of an aeration device according to the present invention for use with a body of water; Figure 2 is an exploded sectional view of the device of Figure 1;

Figure 3 illustrates the manner in which the device of Figures 1 and 2 may be used; and

Figure 4 illustrates in exploded sectional view a second embodiment of an aeration device according to the present invention for use with a body of water.

Referring to Figures 1 and 2, there is illustrated an aeration device 10 comprising a housing 11 which is substantially solid and which includes a main water flow passage 12 having inlet and outlet ends 13 and 14 which are connected to respective couplings 15 and 16 for coupling to a source of water. The ends 13 and 14 are internally threaded to receive a corresponding thread of the couplings 15 and 16. Intersecting the main flow passage 12 and extending at 45° to the main passage 12 is a second passage 17 which has a smaller diameter portion 18 connected to the main passage 12 and a larger diameter internally threaded trailing portion 19 in which is located a venturi unit 20, the venturi unit 20 having a threaded end 21 for threaded engagement with the thread in the trailing passage portion 19. A removable jet or nozzle 22 is provided at the junction between the passage portions 18 and 29 for restricting the flow of water into passage 17 to create a back pressure downstream of the jet or nozzle 22. The venturi unit 20 is of conventional form having a throat adjacent to the jet 22. A small diameter passage 23 extends from the passage portion 19 adjacent to the jet 22 outwardly to an internally threaded coupling 25. A duct in the form of an air tube 26 is connected to the coupling 25 and extends in use above the surface of the body of the water flowing through the venturi unit 20. For mounting purposes, the housing 11 includes opposite end mounting flanges 27 suitably apertured as at 28 for mounting of the device 10 as described further below.

In use, the inlet coupling 15 is connected to a supply of water and the device 10 is submerged. Water is then caused to flow along the main passage 12 as indicated by the arrows in Figure 2. A portion of the water flow also passes into the passage portion 18 and through the jet 22 and venturi unit 20 to thereby create a back pressure in the region 29. This causes air to be drawn in through the passage 23 and duct 26 from the atmosphere. The air is thus introduced into the water flowing through the venturi unit 20 in the form of air bubbles which are thereby passed into the body of water in which the device 10 is submerged through the outlet of the venturi unit 20.

A number of devices 10 can be connected in series in the manner shown in Figure 3 by means of hoses or pipes 30 which are connected between the outlet coupling 16 of one device 10 and the inlet coupling 15 of an adjacent device 10. For this purpose, each device 10 is located adjacent to the water's edge and at a required spacing. A hose 31 is also provided to connect the end device 10 to a pump. Preferably, the pump is associated with a filtration unit (not illustrated). Each device 10 is also connected so that it faces in the same direction. The air tubes 26 are also cut or otherwise provided such that their upper ends will always remain above the water level. The upper ends of the tubes 26 are connected to floats 32 which may be of any shape or configuration, for example, in the shape of a duck. Each device 10 is also mounted on a platform 33 of substantially planar form such that, when lowered into the water, the devices 10 will maintain a stable upright position. The devices 10 and associated platforms 33 may then be located at their required positions in the body of water and submerged. The pipe 31 is then supplied with water from its associated pump. To physically restrain the floats 23, they are connected to the platforms 33 (or devices 10) by cables, wires or lines which are shorter than the tubes 26. This ensures that there is no strain on the air tubes. In addition, the end device of a series of devices has its outlet plugged or alternatively connected to a ring main for recirculation back to the pump.

Each device 10 creates, through the venturi unit 20, a flow of water out of the venturi unit which contains small air bubbles to create dissolved oxygen in the water. As the devices 10 are installed on the bottom of the water body, thermal destratification of the water occurs. In addition, as the outlet from the venturi units 21 is directed upwardly, water and air bubbles are forced upwardly to allow circulation of the whole water body. This ensures that silt or sludge on the bottom of the water body is not stirred up. In the southern hemisphere, the devices 10 are preferably positioned so as to circulate the water in a clockwise manner, whilst in the northern hemisphere, the devices 10 may be arranged to circulate water in the opposite direction. Total circulation of water is achieved in operation as the sun-warmed surface water is thoroughly mixed with the colder bottom water. As dissolved oxygen levels are increased, aerobic bacteria is given the chance to re-establish a balance in the body of water and thus enhance the biodegrading process of any organic matter present therein.

It will be appreciated that the configuration of the device 10 may be substantially changed from that shown and described. For example, the passage 17 may be arranged at other than 45° to the main flow passage 12 and if desired a series of passages 17 carrying venturi units 20 may extend at different angles from the main passage 12. Each platform 33 may also carry more than one device 10.

In the embodiment described and illustrated above, the passage 23 has a diameter of 2mm such that the air bubbles introduced into the liquid are small to ensure efficient oxygen transfer. This dimension however may be varied depending upon the application.

Referring to Figure 4, there is illustrated an alternative aeration device 40 comprising a housing 41 which includes a water flow passage 42 which includes a smaller diameter portion 48 near one end 43 thereof. The passage 42 extending from the other end 49 of the housing 41 is internally threaded in which is located a venturi unit 50, the venturi unit 50 having a threaded end 51 for threaded engagement with the passage 42. A removable jet or nozzle 52 is provided near the portion 48 for restricting the flow of water into passage 42 to create a back pressure downstream of the jet or nozzle 52. The venturi unit 50 is of conventional form having a throat adjacent to the jet 52. A small diameter passage 53 extends from the passage portion adjacent to the jet 52 outwardly to an internally threaded coupling chamber 54 which is adapted to receive an air tube coupling 55. An air tube 56 is connected to the coupling 55 and extends in use above the surface of the body of the water to enable introduction of atmospheric air into the water flowing through the venturi unit 50.

In use, the device 40 is submerged and water is then caused to flow along the main passage 42 as indicated by the arrows in Figure 4. The water flowing through the passage portion 48 and through the jet 52 and venturi unit 50 create a back pressure in the region 59. This causes air to be drawn in through the passage 53 and duct 56 from the atmosphere. The air is thus introduced into the water flowing through the venturi unit 50 in the form of air bubbles which are thereby passed into the body of water in which the device 40 is submerged through the outlet of the venturi unit 50.

In those embodiments of the present invention where water or other liquid to be aerated is also used as the source of fluid for pumping through the aeration devices, blockages can occur where the water or other liquid is in the form of sludge or is otherwise contaminated. Accordingly, air rather than water or liquid is pumped through the devices 10 via supply hoses. Air for this purpose is supplied by an air compressor or blower with appropriate selection of the venturi unit and jet to ensure that atmospheric air is introduced through the ducts in the same manner as previously described.

In aquiculture situations it is preferred that the source of air is provided by a blower which introduces atmospheric air into the supply hoses. Atmospheric air is preferred in these situations as compressors can sometimes introduce contaminants into the body of water. Frictional losses with compressed air are also higher. With the use of air blowers, the system is suitable for use in remote locations where power may be provided by solar energy.

The device of the invention may be made in any size to suit the water or other liquid body in which it is used. Preferably the device is made of a plastics material and is particularly suited to injection moulding. The device may be used in any liquid environment including salt water, effluent and other chemical-contaminating environments. The present invention thus provides an aeration device which is durable, long lasting with no moving parts and requires little maintenance.

Whilst the above has been given by way of illustrative embodiment of the invention, all such modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as defined in the following claims.

Claims

1. An aeration device comprising a housing adapted to be submerged in a body of liquid, said housing including a flow means to allow flow of a first fluid therethrough wherein said flow means includes entrainment means for entraining a gaseous fluid into said first fluid for subsequent introduction into said liquid.

2. A device as defined in Claim 1 wherein the entrainment means for introducing the gaseous fluid into the flow means includes means for creating a back-pressure in the flow means.

3. A device as defined in Claim 1 or Claim 2 wherein means is provided for communicating the flow means with the atmosphere of the surrounding environment such that the back pressure created in the flow means draws in gaseous fluid from the atmosphere into the flow means and the first fluid flowing therethrough.

4. A device as defined in any one of Claims 1 to 3 wherein the flow means comprises a single passage in said housing through which said first fluid flows.

5. A device as defined in Claim 4 wherein the single passage includes the entrainment means.

6. A device as defined in any one of Claims 1 to 3 wherein the flow means comprises a first passage for flow of the first fluid therethrough and at least one second passage intersecting the first passage so that a proportion of the first fluid flowing into the first passage flows through said second passage

7. A device as defined in Claim 6 wherein the second passage includes the entrainment means.

8. A device as defined in Claim 6 or Claim 7 wherein the second passage extends at substantially 45° to the first passage.

9. A device as defined in any one of Claims 6 to 8 wherein the device includes more than one of the second passage adapted such that flow of fluid through the first passage is such that flow output occurs in a number of different directions.

10. A device as defined in any one of Claims 3 to 9 wherein the means for communicating the flow means with the atmosphere includes a duct which extends in use to the surface of the liquid.

11. A device as defined in Claim 10 wherein means are provided for supporting the duct above the surface level of the liquid.

12. A device as defined in Claim 11 wherein the means for supporting the duct is in the form of a float.

13. A device as defined in any one of Claims 2 to 12 wherein the entrainment means incorporates a venturi for creation of the back pressure to draw the gaseous fluid into the first fluid.

14. A device as defined in Claim 13 wherein means are provided for limiting the flow of the first fluid into the flow means.

15. A device as defined in Claim 14 wherein the means for limiting the flow comprises a jet or nozzle.

16. A device as defined in Claim 15 wherein the jet or nozzle is located between the venturi and a source of the flow of first fluid.

17. A device as defined in Claim 16 wherein a duct is connected to the flow means at a position between the jet and the venturi, the duct communicating the flow means with the atmosphere and extending in use to the surface of the liquid.

18. A device as defined in any one of Claims 1 to 17 wherein supporting means are provided for supporting the device on the bottom of a lake, dam or other body of water or other liquid.

19. A device as defined in Claim 18 wherein the supporting means is a platform.

20. A device as defined in any one of Claims 1 to 19 wherein the first fluid is water or other liquid and the gaseous fluid is air or oxygen.

21. A device as defined in Claim 20 wherein the first fluid is water and the gaseous fluid is air.

22. A device as defined in any one of Claims 1 to 21 which further includes an inlet coupling for coupling the flow means to a source of the first fluid.

23. A device as defined in Claim 22 wherein the source of the first fluid is a pump located on a shoreline of the body of the liquid.

24. A device as defined in Claim 23 wherein the source of gaseous fluid is a compressor or blower.

25. A device as defined in any one of Claims 1 to 24 further including an outlet coupling for connecting the device to a second of the device.

26. A device as defined in Claim 25 wherein the inlet and outlet couplings are detachable.

27. A device as defined in any one of Claims 6 to 9 wherein a third passage extends between the second passage and a duct, the duct communicating the flow means with the atmosphere and extending in use to the surface of the liquid.

28. A device as defined in Claim 4 or Claim 5 wherein a further passage extends between the single passage and a duct, the duct communicating the flow means with the atmosphere and extending in use to the surface of the liquid.

29. A device as defined in Claim 27 wherein the entrainment means incorporates a venturi for creation of the back pressure to draw the gaseous fluid into the first fluid, a jet or nozzle is provided for limiting the flow of the first fluid into the second passage and wherein the third passage connects with the second passage between the jet and the venturi.

30. A device as defined in Claim 28 wherein the entrainment means incorporates a venturi for creation of the back pressure to draw the gaseous fluid into the first fluid, a jet or nozzle is provided for limiting the flow of the first fluid into the single passage and wherein the further passage connects with the single passage between the jet and the venturi.

31. A plurality of devices, each device as defined in any one of Claims 1 to 30, interconnected in series and located in use, on the bottom of a lake, dam or other body of water or other liquid.

32. A method of aerating a body of water or other liquid by the use of a device as defined in any one of claims 1 to 30.