THEREOF

Technical field

The present invention relates to water enrichment, and, in particular, relates to apparatus for enriching a water environment, and related methods of use. In embodiments of the invention, oxygen is introduced to enrich the water environment of a tank or a marine enclosure such as for farming fish.

Background

Poor water quality can be an obstacle to sustaining life. Ecosystems may rely on water sources that have a certain composition. Aquatic lifeforms typically need sufficient oxygen in the water in order to live. So-called "deadwater" is acidic and may have oxygen-levels below that typically needed for life. Deterioration in the quality of the water can disturb an ecosystem, such that certain lifeforms or species may be sustained but not others, which may result in a prevalence of certain types of life over others.

In aquaculture farming, the quality of the water in which stocks are produced is generally of key importance to producing a good product. For example, oxygen needs to be available in abundance for fish to survive and develop healthily in a fish farming process. To ensure that stocks have access to oxygen, steps may be taken during farming to move the stock to fresh enclosures or tanks from time-to-time. Aeration techniques are also known, whereby air is introduced into the water to increase oxygen levels. Prior art aeration techniques include rotating a paddle at the surface of the water to stir and "push" air into the water at the surface to upgrade the quality of the water.

Nonetheless existing aeration techniques can have limitations in their effectiveness or in ensuring that such water is sufficiently accessible or digestible by the fish or other stock.

Summary

In light of the above, according to a first aspect of the invention, there is provided apparatus for use in enriching a water environment, the apparatus comprising: first and second passageways for guiding respective first and second fluids into a region in which the first and second fluids are combined for providing a mixture comprising liquid and gas; and an outlet arranged to let the mixture out of the apparatus into the water environment to enrich the water environment.

The mixture may typically be configured so as to produce gas bubbles in the water environment. The mixture produced in the apparatus may contain gas bubbles. The gas bubbles may preferably contain oxygen. The gas bubbles may comprise bubbles of air. The air bubbles may have an average diameter in the range of 1 to 100 micrometres.

The apparatus may further comprise at least one structure configured to facilitate mixing between the first and second fluids for producing the mixture. The structure may comprise a flow constriction, e.g. in the first or second passageway. The structure may comprise at least one opening into said region, e.g. a mixing region, in which the fluids are combined. The flow constriction may be provided by the opening. The opening may be opening through which the first fluid enters the region from the first passageway or an opening through which the second fluid enters the region from the second passageway. The opening may facilitate mixing between the first and second fluids. The structure may be configured for generating turbulence. The structure may comprise at least one formation, such as an edge or other formation, for generating or facilitating mixing, e.g. by production of turbulence, e.g. downstream from the formation inside the apparatus. The edge may be an edge of a surface e.g. a surface of a plate. The formation may be arranged to agitate or affect the flow of either or both of the first and second fluids upon entering the region.

The first and second fluids may typically be guided in respective first and second flows, and the structure may comprise a surface or edge arranged to deflect, disturb and/or turn either or both of the first and second flows to facilitate mixing of the first and second flows.

The region, e.g. the mixing region, may be defined within a chamber of the apparatus such that the mixture is produced in the chamber. The chamber may be defined by a section of tubing.

The first fluid may comprise water pumped through the first passageway from the water environment. The second fluid may comprise air from the atmosphere. The second passageway may be provided by a tube that is in communication with the atmosphere.

The outlet may typically be configured to be submerged in the water environment.

The first and second fluids may enter said region (e.g. a mixing region) through respective openings, which may be separated by a plate or separating structure. The region may be defined within a tube having a longitudinal axis. The apparatus may further comprise a surface arranged at an angle to the longitudinal axis, whereby the second fluid is guided against the surface upon entering into the tube to said region.

The angle of the surface may typically be in the range of 27 to 45 degrees, such as for example 30 to 40 degrees, or more specifically around 35 degrees.

The apparatus may further comprise a pump, which may typically be a submersible pump arranged to be submerged in the water environment.

The pump may be arranged to pump the first fluid through the first passageway.

The first passageway may typically be configured to produce a pressure for drawing the second fluid through the second passageway into the mixing region. The pump may be configured to pump the mixture out of the region and into the water environment.

The water environment may comprise any of: oxygen-deficient water; a body of freshwater or seawater; an inland waterway or lake; a region of sea; and a body of water in a farming enclosure or tank.

The apparatus may in particular be for use in aquaculture. Thus, the apparatus may be for use in farming aquatic organisms including for example fish, crustaceans, molluscs, and/or plants. The water environment may be enriched to facilitate sustaining such organisms in the water environment, e.g. such that the water environment is suitable or is better adapted for such organisms to live and/or develop.

According to a second aspect of the invention there is provided apparatus for use in enriching a water environment, the apparatus comprising:

an arrangement for producing a mixture comprising liquid and gas; and at least one outlet arranged, in use, to let out the mixture into the water environment to enrich the water environment.

The arrangement may typically comprise first and second passageways for guiding first and second fluids into a region, e.g. a mixing region, for combining the first and second fluids for producing the mixture.

The arrangement may be configured to combine first and second fluids. The arrangement may comprise at least one structure configured to facilitate mixing between the first and second fluids, for producing the mixture. The first fluid may comprise a liquid. The second fluid may comprise a gas.

The mixture may typically be configured so as to produce gas bubbles in the water environment. The mixture may contain gas bubbles.

According to a third aspect of the invention there is provided a method of enriching a water environment using the apparatus of the first or second aspects of the invention.

According to a fourth aspect of the invention, there is provided a method of enriching a water environment, the method comprising the steps of:

a. producing a mixture comprising liquid and gas; and

b. letting the mixture into the water environment to enrich the water environment.

The mixture may be produced by combining first and second fluids. The first and second fluids may typically be guided into a region, e.g. a mixing region, to combine the first and second fluids to produce the mixture.

Enriching the water environment may comprise increasing an air, oxygen and/or gas content in the water environment, e.g. for promoting life in that environment, e.g. an aquacul- ture environment. Enriching the water environment may comprise inserting air, oxygen and/or gas into the environment.

Any one of the abovementioned aspects of the invention may include further features as described in relation to any other aspect, wherever described herein. Features described in one embodiment may be combined in other embodiments. For example, a selected feature from a first embodiment that is compatible with the arrangement in a second embodiment may be employed, e.g. as an additional, alternative or optional feature, e.g. inserted or exchanged for a similar or like feature, in the second embodiment to perform (in the second embodiment) in the same or corresponding manner as it does in the first embodiment.

Embodiments of the invention are advantageous in various ways as will be apparent from the specification throughout.

Description and drawings

There will now be described, by way of example only, embodiments of the invention with reference to the accompanying drawings in which:

Figure 1 is a schematic cross-sectional representation of an apparatus according to an embodiment of the invention;

Figure 2 is a close-up cross-sectional representation of part of the apparatus of Figure 1 ;

Figure 3 is a cross sectional representation of part of the apparatus along A-A' in

Figure 2; and

Figure 4 is a representation of the apparatus of Figures 1 to 3, in use.

In Figure 1 , an apparatus 1 for enriching a water environment (not shown) is depicted. The apparatus 1 is suitable for use in fish farming or the like, where the apparatus 1 may be used in the water environment within an enclosure for containing fish.

The apparatus 1 is designed to be placed, at least partially submerged, in the water environment. The apparatus 1 has an arrangement for producing a mixture. The apparatus 1 has a mixing region 12 and first and second passageways 20, 30 for guiding respective first and second fluids into the mixing region 12 where they are combined and mixed together to obtain the mixture. The first fluid is in the form of water from the surrounding water environment, and the second fluid is in the form of air from the atmosphere. Accordingly, by combining the first and second fluids, the resulting mixture is a mixture of water and air. The apparatus 1 has an outlet 50 through which the mixture produced in the mixing region is inserted into the water environment, generating bubbles of air in the water that enrich the environment. The bubbles are distributed as a "cloud" in the water with an average maximum diameter typically in the range of 1 to 1000 micrometers. Parts of the apparatus 1 are shown in close-up in Figures 2 and 3 to which reference is additionally now made.

The apparatus 1 has a pump 60, see Figure 1 , for pumping the water in a flow in the first passageway 20 into the mixing region 12. The water enters the mixing region 12 through a first opening 22.

The air travels in a flow in the second passageway 30 and enters the mixing region 12 through a second opening 32.

On approaching the first opening 22 in the direction of flow, the opening of the first passageway 20 reduces in diameter so that a flow constriction is provided at the first opening 22. This constriction causes an increase in flow speed and produces a region of low pressure where the water enters the mixing region 12.

The low pressure generated by the constriction, allows the air to flow into the mixing region 12 in the second passageway 30. In this case, the second passageway 30 is connected with open communication to the atmosphere above the surface of the water environment. This can be done by using tubing with an inlet above the water surface to direct air into the second passageway 30. Accordingly, the low pressure that is generated via the constriction needs to be significantly lower than atmospheric pressure in order to direct the air into the mixing region 12.

The mixing region 12 is defined in inside a pipe section 10. Thus, the pipe section 10 in effect provides a chamber in which the water and air are mixed together to produce the mixture, where the mixture is contained by the inner wall of the pipe. The mixture is driven through the pipe section 10 and out of the outlet 50 by operation of the pump 60.

The first and second passageways 20, 30 are provided through a further two respective pipe sections 21 , 31 .

The apparatus 1 has a structure configured to facilitate the mixing between the air and the water. In particular, a formation in the form of a plate 40 is positioned in the T-junction of the pipe sections 10, 21 , 31 . The plate 40 is positioned between the first and second openings 22, 32, and interacts with the air and the water entering the mixing region 12. The plate 40 has a planar first surface which constricts the water at the opening 22, and a planar second surface which guides and interacts with the air at the opening 32. The plate 40 is positioned at an acute angle to both the long axis B and the long axis C of the pipe sections 21 , 31 . The planar first and second surfaces, being parallel to one another on opposite sides of the plate 40, are therefore also arranged at an acute angle with respect to both of the axes B, C. The plate 40 extends inwardly from a wall of first passageway 20, and terminates at an edge 41 , which in this case is coincident with the axis B. The angle in this example is 35 degrees.

In other variants, the plate 40 may extend a different distance inward from the wall, and the angle of the plate 40 or of the first and second surfaces of the plate 40 may be different than that illustrated. Structures that are different to the plate 40 as exemplified here may be used instead, and such structures may provide surfaces which are inclined and/or interact with the flow entering the mixing chamber 12. For example, a block may have a first surface arranged to produce the constriction at the first opening 22 and a second surface arranged to interact with the air at second opening 23, and the first and second surfaces may be pitched with different angles relative to the axes B, C.

By directing the air and water past the surfaces of the plate 40 at the respective openings 22, 32, mixing may be encouraged by the plate 40 and indeed also by the plate edge 41 . Mixing may be encouraged by virtue of the constriction producing a low pressure, and enlargement of the internal diameter downstream of the plate 40.

The air entering the mixing region 12 at the opening 32 is directed against the surface of the plate. The can disrupt and deflect the flow of air as it passes into the chamber 1 1 . The plate 40 can generate turbulence downstream of the edge 41 , which can result in unsteady flow conditions including effects such as swirls, eddies in the water and/or air components as they undergo mixing in the mixing region. The mixing preferably generates a mixture in the mixing region 12 including large numbers of small-sized air bubbles in water.

The bubbles of air in the mixture in the mixing region typically have an average maximum diameter in the range of 1 micrometer to 1 millimeter. The nature of mixing and size of bubbles that are generated by that mixing can be controllable by the configuration of the plate 40. In other embodiments, setting the plate such that the angles a and β of the surfaces are between 27 to 45 degrees with respect to the axis B may be used to good effect.

The configuration of the openings 22, 32, e.g. in terms of the distance that the plate 40 extends from the wall of the passageway 20 and the pitch angles a and β, may be adapted to accommodate use and facilitate mixing and performance of the apparatus 1 at different depths in parts of the water environment of different salinity.

Referring now to Figure 4, the apparatus 1 is illustrated in a water environment 70. The mixture is being jetted out of the outlet 50, producing a region 71 in the environment that is dense with bubbles air from the mixture. The bubbles of air contain oxygen. In this way, the apparatus can enrich the water environment with oxygen such that living conditions for farm stock or aquatic lifeforms in general can be enhanced.

Further details of the apparatus 1 are now described. The outlet 50 includes a directing structure 51 , see Figure 1 , at an end of the pipe section 10 for directing the mixture into the water environment. By way of the mixture, the environment is oxygenated, since the mixture is highly aerated and includes many air bubbles densely distributed. Each bubble defines a contact area between the air in the bubble and the water. By producing many very small bubbles, e.g. in the micrometer range, the total contact area of contacts between the air and water in the mixture is correspondingly high. Oxygen may thus be made available in a form that can be easily accessible for fish or other lifeforms.

The pump 60 is arranged inside a housing 80. An annulus 65 is defined between the housing 80 and pump 60, into which water enters from a surrounding region 66 of the water environment outside of the housing 80. The water enters from the surrounding region 66 through an inlet mesh 67. The mesh 67 helps to keep out unwanted matter from the vicinity of the pump 60. The pump 60 includes a motor 61 , which is coupled via an axle (not shown) to rotatable members 62 which are arranged in series and which rotate about a pump axis 70 (coincident with the axis B along a centre of the housing 80). By operating the pump motor 61 , the members 62 rotate so as to draw water from the annulus 65 and through the mesh 67 into a pump inlet 63. Using the rotatable members 62, the water from the pump inlet 63 a pressure is generated at the outlet of the pump for driving the water along the first passageway 20 and pumping the mixture out of the apparatus 1 . In other variants, other kinds of pump may be used.

The housing 80 in this case is cylindrical, although more generally this does not need to be the case. In other embodiments, a source of air may be used which is actively pressurized to some level above the atmospheric pressure, to push the air along second passageway 30 and into the mixing chamber 12, if for example the pressure in the mixing chamber is not lowered sufficiently.

The apparatus 1 as exemplified may operate in use with the pump 60 submerged at a depth of 5-6 m below the water surface.

The pump 60 in the arrangement illustrated in Figure 1 can further deliver a volume rate of liquid through the pump of 120 cc per hour, although this may be scaled up or down according to requirements.

As can be seen, the pump 60 is supported centrally within the housing 80 by centralizing members 68a, 68b, attached to the housing 80 and to the pump 60.

The second passageway 30 passes through a wall of the housing 80. Typically, a hose or the like may be connected to the pipe section 31 , for feeding air along the passageway 30. A seal 69 is provided between the pipe section 31 and the wall of the housing 80, so that water is contained and preferably does not leak out of the annulus 65 between the pipe section 31 and the housing 80. The annulus 65 is also sealed by an elastomer ring seal 13 provided around the pipe 10. The seal 13 therefore closes off the annulus 65 at one end of the housing 80, such that the housing 80 acts as a container containing a reservoir of filtered water in the annulus 65 for use by the pump 60.

The pump motor 61 operates with the motor immersed in a liquid such as glycol. The use of liquid in this way can facilitate operation of the pump at depth by counteracting pressure exerted by the water column. By way of the liquid being of glycol, harmful contamination of fish stock may be avoided risk in the event of accidental leakages of the liquid into the environment.

The pump motor 61 is operated electrically. An electrical supply line 81 is fed through the housing 80 to the motor 61 . With the apparatus 1 deployed, and operating the pump 60, water is pumped continuously through the first passageway 20. Air is simultaneously drawn through the second passageway 30, such that the air and water are mixed in the mixing region 12, producing a mixture. The mixture is driven along the pipe section 10 toward the outlet 50 due to the action of the pump 40. The mixture then passes out the opening of the outlet 50 into the water environment for enriching the water.

When deployed, the housing 80 and pump 60 is fully submerged. The outlet 50 for the mixture is also submerged underwater. An open end of a hose for supplying air from the atmosphere through the second passageway 30 may be provided by above water. Likewise, an electric power source and connecting cables for operating the pump 60, and floatation devices for the apparatus 1 , may be arranged above water. Such floatation devices may be used to suspend the apparatus 1 and/or to position components thereof, at the desired depth. Typically, the apparatus 1 is provided such that a long axis of the apparatus, e.g. the axis B, is horizontal. This may facilitate supply of air and water into the mixing region 12 and the nature of mixing in the mixing region 12.

Significant increases in oxygen levels can be obtained in the body of water by aerating the water as described using the apparatus 1 . Measured results indicate an increase in oxygen content in the range of 92-100% after operating the apparatus for a period of only a few hours.

Various modifications and improvements may be made without departing from the scope of the invention herein described.