WO2012134390A1

WO2012134390A1 - Method and arrangement for the supply of gas, or a mixture of gases, to a fluid

Info

Publication number: WO2012134390A1
Application number: PCT/SE2012/050360
Authority: WO
Inventors: Axel Fredriksson
Original assignee: Sorubin Ab
Priority date: 2011-04-01
Filing date: 2012-04-02
Publication date: 2012-10-04
Also published as: EP2694198A4; SE1100239A1; EP2694198A1; SE535741C2

Abstract

The invention concerns an arrangement (1) for the processing and addition of a gas (2), or a mixture of gases, to a fluid (3). The arrangement comprises at least one vessel (4) that is intended to be at least partially submerged in the fluid (3), the vessel (4) of which comprises at least one inner compartment (5) provided with at least one inlet (10) for the input flow of fluid into the vessel (4) and at least one outlet (11) for the output flow of fluid from the vessel. The arrangement (1) comprises at least one flow-creation arrangement (14) through which an output flow of fluid (3) from the vessel (4) takes place during the formation of at least one vortex (27) in the inner chamber (5). What is unique for the present arrangement is that the inlet (10) is constituted by at least one input flow channel that is located in the lower part of the vessel (4) and that the input flow channel is directed essentially in the tangential direction of the vessel (4) obliquely upwards within the interval 91 to 125 degrees relative to the axial direction of the vessel. What is furthermore unique is that the flow-creation arrangement (14) is constituted by an impeller (16) and that the impeller (16) is located at the outer surface of the vessel at a distance from the bottom of the vessel. The present invention comprises also a method for the use of the arrangement.

Description

METHOD AND ARRANGEMENT FOR THE SUPPLY OF GAS, OR A MIXTURE OF

GASES, TO A FLUID

Technical area

The present invention concerns a method and an arrangement for the supply of gas, or a mixture of gases, to a fluid, as specified by the claims.

Technical background and prior art technology

It is necessary in many contexts and fields to supply gas, or mixtures of gases, to various types of fluid. This need is present in several different fields and applications, such as, for example, in industrial processes, when cleaning water, when treating leach water, in fish farming, in sedimentation plants, when using flotation technology, when manufacturing ethanol, during processes in the paper pulp industry, in association with the oxygenation of water courses and in several other fields.

Existing methods for supplying gas, or mixtures of gases, to a fluid are subject to many different types of problem. The principal problem with existing arrangements and methods is either that these consume much energy or that they do not function satisfactorily. For example, the methods and the arrangement that are currently used for the oxygenation of a fluid, such as water and similar, either consume much energy or do not function satisfactorily.

The types of plant that are currently used to oxygenate water such as, for example, ejector pumps and membrane pumps, all suffer from problems. The ejector pumps, for example, have problems with these becoming clogged during use. The problem with membrane aerators is that the function of these becomes poorer as time passes, caused by the pores in the membrane becoming clogged. Furthermore, the membrane ages quite rapidly and must be regularly exchanged. The said problems lead to the membrane aerators having inadequate reliability, and this can cause expensive interruptions in operation and repair. Existing facilities have problems also with high heat production and high levels of noise.

Several types of arrangement have been developed in order to reduce the amount of energy that is consumed in order to oxygenate or agitate a fluid. One example of these types is constituted by arrangements that agitate or oxygenate, or agitate and oxygenate, the fluid by a vortex. In the patent document AT265991 , for example, there is described a variant of a vessel that comprises at its bottom a vortex-forming arrangement that forms a vortex in the vessel. The design is not principally intended to be used for the oxygenation of the fluid, being instead principally intended to be used for agitation. The design according to the patent document, therefore, differs to a large extent from the present invention. There is described in the patent document SE460706 with its corresponding international patent application PCT/SE88/00684 an agitator that is intended to create a natural vortex in a fluid such as water. The agitator comprises a vessel of hyperbolic form that creates a vortex in a fluid such as water through rotation. Only the vortex former is described in the patent document SE460706, and not the applications in order to use this. Applications for the use of the agitator have been added to the international patent application as examples. The applications given as examples comprise problems in that the vortex that is created is disturbed by the inflow of water. The design according to the patent document, therefore, differs to a large extent from the present invention.

An arrangement for supplying a gas, or a mixture of gases, to a fluid is described also in the patent document SE500416. The problem with this design is that the formation of a vortex does not take place in an optimal manner, and that the design is so constructed that the vortex is disturbed by the inflow of the fluid. The design has the problem also that when it is used for the supply of air (oxygen) to water it emits a disturbingly high level of noise. The design according to the patent document, therefore, differs to a large extent from the present invention.

One problem with the existing designs according to the patent documents SE460706 and SE500416 is constituted by the reliability of the equipment. This is compromised by, among other effects, the compartment in the suction means, through which the fluid is to flow, becoming easily clogged. Clogging is a particularly commonly occurring problem if the fluid that is to be oxygenated comprises impurities that are relatively large relative to the channels in the suction means. In particular, long-fibred impurities such as rags, material fragments, hair and other materials can lead to clogging of the channels in the suction means.

Furthermore, an additional problem with the existing designs is that the oxygenation effect of the arrangements needs to be improved further.

Purpose of the present invention

The principal purpose of the present invention is to achieve an improved arrangement and an improved method by which gas, or a mixture of gases, can be added to a fluid with a low energy consumption. A second purpose of the present invention is to create an arrangement and a method that provide a considerably improved vortex-forming function than prior art designs provide. A further purpose of the present invention is to create a stable vortex in a fluid. A further purpose of the present invention is to create an arrangement for the oxygenation of fluid that emits a considerably lower level of noise to the surroundings than previously known designs. A further purpose of the present invention is to create an arrangement that can be maintained simply and cost-effectively. A further purpose of the present invention is to create a design that is considerably more reliable than prior art designs. It is a further purpose of the present invention to create an arrangement that oxygenates more efficiently than prior art designs.

Brief description of the drawings referred to in the following paragraphs

Reference will be made in the following detailed description of the present invention to the following drawings. These are briefly described in the following list of drawings. The embodiments in the drawings are given as examples and are not limiting for the protective scope of the present patent application. Note that the drawings are schematic and that details may, therefore, have been omitted from them.

Figure 1 shows the present invention seen from the side.

Figure 2 shows a section of the present invention seen from the side.

Figure 3 shows part of Figure 2.

Figures 4-6 show the arrangement seen from above with different numbers of inlets.

Figure 7 shows a cross-section of the arrangement seen from above in a downwards direction.

Figure 8 shows the angular position of the impeller relative to the bottom of the vessel, a wear ring.

Figure 9 shows one type of impeller, given as an example. Figure 10 shows a cross-section of the impeller in Figure 9. Figure 11 shows an alternative embodiment of an impeller. Figure 12 shows a cross-section of the impeller in Figure 11. Figure 13 shows a variant of a wear ring, given as an example. Figure 14 shows a variant of the wear ring with tearing grooves. Detailed description of the invention

With reference to the drawings, there is shown an arrangement 1 for the supply of gas 2, or a mixture of gases, to a fluid 3. The gas 2 may be constituted by, for example, oxygen or another gas. The mixture of gases may be constituted by air or another type of mixture of gases. The fluid 3 may be constituted by a liquid or a mixture of liquids. The fluid 3 may be constituted by, for example, water or another type of fluid to which gas or a mixture of gases is to be supplied.

The arrangement 1 comprises at least one vessel 4, a container or similar, that comprises at least one inner chamber (vortex chamber) 5. The vessel 4 is provided at its lower end 6 with at least one bottom 7. The bottom 7 is provided with at least one penetrating hole 8 that is preferably located in the centre of the bottom, or placed in the vicinity of the centre.

The vessel 4, which is preferably extended, is intended to be partially submerged in the fluid 3 in the essentially axial direction of the vessel 4. The relative length of the part 9 of the vessel 4 that is submerged in the fluid, relative to the complete length of the vessel, may differ to a large degree within the framework of the present invention.

The vessel 4 is in connection with the surrounding fluid 3 through at least one inlet 10 for the fluid and at least one outlet 11 for the fluid. During lowering of the vessel 4 into the fluid, an input flow of the fluid will take place through the inlet 10 into the inner chamber 5 of the vessel. Furthermore, the vessel 4 comprises at least one inlet for gas, or mixtures of gases, into the inner chamber. The inlet can be achieved through parts of the upper part of the arrangement comprising openings to the surrounding atmosphere or to an inner compartment that comprises gas or a mixture of gases such as air. What is important for the function of the arrangement is that the inlet for gas, or mixture of gases, is located above the surface of the fluid into which the vessel has been partially submerged.

It is preferable that the vessel be provided with at least one cover 12, a protection or similar. The cover 12 is provided at its upper end with at least one inlet 13 (an inlet for gas or mixtures of gases) and preferably with at least several inlets 13. The cover 12 may comprise at least one filter. The principal technical effect of the cover 12 is that it prevents, for example, animals and objects from entering the inner compartment (the vortex chamber). The form of the cover may differ greatly within the framework of the innovative concept. In the embodiment shown as an example in Figure 1 , the vessel 4 is constituted by a cylindrical vessel with a circular cross-section. The cylindrical vessel 4 may possess rotational symmetry. It is conceivable that the vessel 4 in alternative embodiments may have another form that is suitable for its purpose. It is conceivable, for example, that the vessel 4 has an edged form and that the vessel 4 has a cross-section that comprises at least three edges, and preferably at least six edges. It is further shown in the drawing that the vessel 4 has a plane bottom 7. The bottom 7 may, however, in alternative embodiments have another form that is suitable for its purpose.

The design comprises at its lower end a flow-creation arrangement 14 that is driven by at least one drive unit 15. In the preferred embodiment of the present invention that is shown, the flow-creation arrangement 14 is constituted by an impeller 16 or similar. The drive unit 15 is constituted by a suitable type of drive unit that is appropriate for its purpose, being prior art technology. In the embodiment given as an example, the drive unit is connected to the vessel 4 by at least one attachment arrangement 7 or similar.

The impeller 16 is located at a distance from the outer surface of the bottom of the vessel, alternatively a wear ring. It is preferable that the distance between the impeller 16 and the bottom 7 of the vessel 4, alternatively the wear ring at the vessel, be arranged such that it can be adjusted.

This can take place through the attachment arrangement 17 comprising an adjustable function. The adjustable function is preferably achieved using prior art technology, and for this reason it will not be described in more detail in this patent application. The adjustable function allows that an adaptation of the distance between the impeller 16 and the bottom 17 (or alternatively the wear ring) can take place depending on the degree of impurity of the pumped (oxygenated) fluid.

The adjustable function allows also a possible oblique placement of the impeller 16 relative to the wear ring, the bottom 7, or oblique placement of the wear ring, the bottom 7, relative to the impeller 16. See Figure 8. The impeller 16 and the wear ring, the bottom 7, are fixed or adjustably set at an angle a relative to each other.

The impeller 16 is fixed or adjustably positioned, mounted, arranged in a manner that allows the angle to be adjusted relative to the wear ring, the bottom 7. A central axis A1 of the impeller 16 is located at an angle a relative to a central axis A2 of the wear ring, the bottom 7.

The design may be also such that the wear ring, the bottom 7, is fixed or adjustably positioned, mounted, arranged in a manner that allows the angle to be adjusted relative to the impeller 16. A central axis A2 of the wear ring, the bottom 7, is located at an angle a relative to a central axis A1 of the impeller 16. The impeller 16, or the wear ring, the bottom 7, can be set at an angle relative to the wear ring, the bottom 7, or the impeller 16, by, for example, the drive unit being able to suspend the attachment arrangement 17 that is united with the wear ring, the bottom 7. The attachment arrangement 17 that is shown in an embodiment comprises a number of attachments, legs, where at least one leg is somewhat longer, or shorter, than the other legs in order to create the angular placement, the oblique placement. The attachment arrangement 27 [sic, "17"], the legs, which in the embodiment shown constitutes also the attachment arrangement 17 that unites the drive unit with the vessel, may comprise stud bolts, stud bolts that have a dimension that is suitable for the use. The displacement takes place with sheaths of different lengths or with, for example, at least one nut on each side of the drive unit. It is possible in this way to adjust in stepless increments the oblique placement of the drive unit, the impeller, relative to the wear ring, the bottom 7, or vice versa.

This possibility of adjustment allows an adaptation of the angular position of the impeller 16/the wear ring, of the bottom, relative to the wear ring, the bottom 7/the impeller 16 to take place depending on the degree of impurity of the fluid. In the case in which the impurity in the fluid comprises large parts, a larger angle a is required, and if the impurities are smaller, a smaller angle a can be used. A large angle a allows a larger fall region for the impurities, which facilitates the displacement of the impurities away from the impeller 16 and prevents the impurities becoming attached to the impeller 16.

A small angle a increases the efficiency of the arrangement, a large angle a reduces the efficiency of the flow-creation arrangement. In order to achieve maximal efficiency of the arrangement, the angle a must be balanced against the degree of impurity of the fluid and the size of the impurities.

During use of an arrangement according to the invention in fluid having the same degree of impurity over time and having the same size of the impurities over time, the location of the impeller relative to the wear ring, the bottom 7, or vice versa, the angle a, can be held constant over time. The impeller 16 is in this case fixed positioned with an angle a relative to the wear ring, the bottom 7.

During use of an arrangement according to the invention in fluid having a varying degree of impurity over time and having a varying size of the impurities over time, the location of the impeller relative to the wear ring, the bottom 7, or the location of the wear ring relative to the impeller 16, the angle a, can be adjusted over time. The angle a can be varied within the interval 1-80° or it is possible that a further narrowing of the interval to 1-50° or to 1-30° gives a further highest efficiency based on impurities with a size that can be mechanically handled and processed. With reference to Figures 9 and 10, there is shown an embodiment of the impeller 16 that is used in the present design, given as an example. Figures 4A and 4B [sic] show only one variant of many conceivable embodiments of impellers that can be used in the present design. The impeller shown in the drawings, therefore, is not to be seen as limiting for the protective scope of the present invention. The diameter of the impeller, furthermore, depends on the power available and on what type of drive unit, for example whether two-pole or four- pole, is used in the arrangement. The impeller 16 comprises a hub disk 18 that is provided with at least three wings 19, or similar, extending along the complete stretch, or part of it, between the centre 20 of rotation of the impeller 16 and its circumference 21. In the embodiment shown in Figure 4A is shown an impeller with five wings 19. It is preferable that the impeller 16 be of an open type such as an impeller 16 of vortex type. The design of the impeller leads to the risk that the impeller becomes clogged by impurities being considerably reduced.

The form of the wings 19 may vary to a large extent within the framework of the present innovative concept. The angles of the inlet and of the outlet of the impeller may vary to a large extent within the framework for the innovative concept. The form of the wings may, for example, deviate from that of the wings in the drawings shown in which the inlet angle is relatively shallow and the outlet angle is relatively steep.

With reference to Figures 1 1 and 12, there is shown a first alternative embodiment of the impeller 16 (the suction means). In this embodiment, at least one of the wings 19 of the impeller comprises a groove 22. It is preferable that all blades, wings 19, of the impeller are provided with at least one groove 22. It has surprisingly proved to be the case that the bubble-creating effect of the impeller increases if the blades 19 of the impeller are provided with grooves 22. The groove 22 extends from the edge 21 of the impeller partially through a part of the wing height of the impeller. It is preferable that the groove be obliquely angled as shown by the angle V1 , relative to the hub dusk 18 of the impeller. It is preferable that the angle V1 be less than 90 degrees and that it preferably lies within the interval 45 to 60 degrees.

With reference to Figure 13, there is shown an embodiment of the present arrangement as an example, which embodiment comprises at least one wear ring 24. The task of the wear ring 24 is to reduce wear on the outer surface of the bottom 7 of the vessel 4. It is preferable that the wear ring 24 be constituted by a disk-shaped material with a penetrating hole 25 at its centre. What is unique to the present wear ring 24 is that it comprises at least one groove 26 (in the material in the direction towards the impeller). It is preferable that the wear ring 24 be provided with several grooves. In the embodiment given as an example, the wear ring comprises three grooves 26. The groove 26 essentially solves the problems with fibres and similar becoming collected on the impeller and the wear ring, leading to an impaired function of the present arrangement. The risk of the compartment between the wear ring 24 and the impeller becoming clogged is considerably reduced through the grooves 26. The grooves 26 lead to pulses of pressure being created when the blades 18 [sic] of the impeller pass the grooves 26, with the effect that fibres and similar that have built up on the impeller 16 and the wear ring 24 are torn away (released). It is preferable that the groove start at a distance (A) from the edge of the hole. The distance A3 may vary within the framework of the present patent application. In the embodiment shown, however, the distance A constitutes 1.5 to 3 times the width of the groove 26. The grooves 26 extend in the embodiment shown in a direction that preferably lies within the interval 80 to 105 degrees relative to the radial direction of the wear ring, shown as angle V2. In the embodiment shown as an example in Figure 13, the grooves are essentially directed at 90 degrees relative to the radial direction of the wear ring. The length of the grooves is adapted such that they extend a length that leads to the groove extending outside of the edge of the impeller, i.e. it extends outside of the peripheral edge of the impeller. The groove in the embodiment shown is straight. In alternative embodiments, it is conceivable that the groove have another form that is suitable for its purpose. The form of the groove along its longitudinal direction, thus, may deviate from a straight form.

Figure 14 shows a wear ring 24 intended to be used in cases of a large presence of long fibres in the pumped medium, the fluid, that is to be oxygenated, for example in the case of waste water that has not undergone coarse cleaning. This wear ring 24 is provided at a central hole 8 in the disk with grooves 8.1 that extend out from the hole 8. The grooves may be principally tangentially directed out from the hole 8. Long fibres will become attached at these grooves 8.1 and will be torn away due to the motion of the fluid. The grooves 8.1 are known as "tearing grooves".

The use of a wear ring is particularly important if the vessel is of a polymer material or other material that is soft or easily worn, or soft and easily worn. The wear ring reduces to a significant extent wear on the bottom of the vessel that is caused by particles and other material.

When the vortex-forming suction means 14 has been placed in rotation, suction is created at the centre 20 of the impeller 16, which creates a vertical flow down towards the impeller 16 and out towards the peripheral part of the impeller [19 is the blades, and 17 is the attachment fittings for the drive unit]. The suction of the fluid down towards the vortex-forming impeller 16 creates a vertical vortex 27 from the surface 28 of the fluid down through the inner compartment (the vortex chamber) and out through the hole 8 in the bottom of the vessel to the impeller 16. Gas, or the mixture of gases (such as air), is drawn by the vortex 27 that has been created down towards the impeller 16. When the mixture of gas and fluid is drawn down, towards the impeller 16, swarms 29 of bubbles form, such as, for example, microbubbles and other types of bubbles. The bubbles in the swarms 29 of bubbles lead to the gas, or the mixture of gases, being added to the fluid 3.

What is furthermore unique with the present arrangement is that the input flow of fluid to the inner part of the vessel takes place in the lower half of the vessel, and preferably in the lower fifth of the vessel. In the embodiment shown, the input flow of fluid takes place through an inlet 10 in the vicinity of, or in the close vicinity of, the bottom 7 of the vessel 4. It is preferable that the inlet 10 be constituted by an inlet channel.

It is preferable that the input flow of the fluid take place through at least one inlet 10 in essentially the tangential direction of the vessel. It is preferable that the inlet be angled as shown by the angle V relative to the axial direction of the vessel. It is preferable that the angle V lie within the interval 91 to 135 degrees, relative to the axial direction of the vessel. It is conceivable that the input flow in alternative embodiments take place at a different direction relative to the vessel than an essentially tangential direction. It is further conceivable that the angle relative to the axial direction deviate from the angle specified above. It is conceivable that at least one of the diameter and the direction of the input flow be made adjustable in alternative embodiments.

A direction of the input flow that is in the essentially tangential direction of the vessel leads to the vortex formation in the vessel being reinforced through the input flow contributing to a rotation of the fluid that flows into the vessel. The obliquely upwards direction of the input flow further leads to an upwardly directed vortex of fluid being created, which transitions into a downwardly directed vortex that consists of a mixture of fluid and gas. The design promotes the formation of a stable downwardly directed vortex consisting of fluid and gas. The stable upwardly directed vortex of fluid inside the vessel creates an upwardly directed force for the complete arrangement (the equipment) that results in the fall in pressure in the inlet in the impeller being so low that the fall in pressure in the suction means becomes less than the vapour-formation pressure of the fluid, and this results in microbubbles arising inside the suction means. These microbubbles are mixed with the fluid and gas in cases in which this is desirable for the function, which leads to an increase in volume of the gas in the fluid, which gives rise to a unique addition of gas to the fluid (the liquid). The inlet channels in the drawings given as examples are directed in the clockwise direction. It is conceivable that the inlet channels be directed in the anti-clockwise direction in alternative embodiments.

The construction comprises also at least one positioning and fixture arrangement 30 with which the position of the arrangement relative to the fluid and the surface of the fluid can take place. The fixture arrangement may be, for example, fixed attached to at least one object such as a fixed fixture (not shown in the drawings) or connected to a displaceable object such as at least one floating body (not shown in the drawings). It is conceivable that the arrangement be placed suspended from a wire, or rope or similar in alternative embodiments. It is furthermore conceivable that the arrangement be fixed by a combination of the objects named above. It is furthermore conceivable that the arrangement be placed on a stand such as a tripod or similar. The arrangement may be provided also with separate legs or similar constructions.

Construction details and partial methods that are obvious for one skilled in the arts within the field that the method and arrangement relate to may have been excluded from the detailed description of the present invention. Such obvious construction details and partial methods are included to the extent that is required for a satisfactory function of the present method and arrangement to be obtained.

Even if certain preferred embodiments have been shown in more detail, variations and modifications of the arrangement may become apparent for ones skilled in the arts in the field that the invention concerns. All such modifications and variants are considered to lie within the framework of the attached patent claims. It is conceivable that the invention be defined as an arrangement to create a stable vortex in a fluid. It is conceivable that the impeller in alternative embodiments have a number of wings that is fewer than three. Furthermore, it is conceivable that a closed channel wheel with at least one channel be used in alternative embodiments, instead of the impeller described.

Advantages of the invention

A number of advantages are achieved with the present invention. The most obvious is that an overall method that is considerably more energy-efficient that previously known methods for the addition of a gas to a fluid is achieved. A further advantage of the present design is that it emits less noise than previously known designs. The present design is also more cost- effective than previously known designs. The present invention has the advantage also that it creates a stable vortex in the vessel. A further advantage of the present invention is that the design is considerably more reliable than previously known designs. It is furthermore an advantage of the present invention that the arrangement oxygenates a fluid in a considerably more efficient manner than previously known designs.

Claims

1. An arrangement (1) for the processing and addition of a gas (2), or a mixture of gases, to a fluid (3) comprising at least one vessel (4) with at least one inner chamber (5) that is intended to be at least partially submerged in the fluid (3), the vessel (4) of which comprises at least one inlet (10) for the input flow of fluid into the inner chamber (5) of the vessel (4) and at least one outlet (11) in the bottom (7) of the vessel (4) for the output flow of fluid from the inner chamber (5) of the vessel (4) and at least one inlet (13) for gas (2) into the inner chamber (5) of the vessel (4), the arrangement (1) of which comprises at least one flow-creation arrangement (14) with its associated drive unit (15) that creates an output flow of the fluid (3) out through the outlet (11) from the vessel (4) during the formation of at least one vortex (27) in the inner chamber (5) and swarms (29) of bubbles of gas in the outwardly flowing fluid (3), characterised in that the inlet (10) is constituted by at least one input flow channel that is located in the lower fifth of the vessel (4) and in that the input flow channel is directed essentially in the tangential direction of the vessel (4) obliquely upwards within the interval 91 to 125 degrees relative to the axial direction of the vessel (4) and that the flow-creation arrangement (14) is constituted by an impeller (16) that is positioned at the outer surface of the vessel with at least one attachment arrangement (17) at a distance from the bottom (7) of the vessel (4) and the outlet (11) that can be adjusted.

2. The arrangement (1) according to claim 1 , characterised in that the arrangement comprises at least one wear ring (24) that is connected to or integrated with the lower side of the bottom (7) of the vessel (4) in association with the outlet (11).

3. The arrangement (1) according to claim 2, characterised in that the wear ring (24) comprises at least one groove (8.1 , 26).

4. The arrangement (1) according to claim 3, characterised in that the groove (26) in the wear ring (24) is directed essentially within the interval 80 to 105 degrees relative to the radially direction of the wear ring (24).

5. The arrangement (1) according to at least one of the preceding claims, characterised in that the impeller (16) comprises at least one hub disk (18) from which at least three wings extend, whereof at least one of the wings comprises at least one groove (22) that extends from the edge of the wing in the direction towards the hub disk (18) of the impeller (16).

6. The arrangement (1) according to at least one of the preceding claims, characterised in that the groove (22) is obliquely directed relative to the radial direction of the hub disk within the interval 45 to 60 degrees.

7. The arrangement (1) according to at least one of the preceding claims, characterised in that the fluid (3) is constituted by water.

8. The arrangement (1) according to at least one of the preceding claims, characterised in that the gas (2) is constituted by air.

9. The arrangement (1) according to at least one of the preceding claims, characterised in that the impeller (16) and a wear ring (24), the bottom (7), are fixed or adjustably set at an angle a relative to each other.

10. The arrangement (1) according to claim 9, characterised in that the impeller (16) is fixed or adjustably set at an angle a relative to the wear ring (24), the bottom (7).

11. The arrangement (1) according to claim 9 or 10, characterised in that the wear ring (24), the bottom (7), is fixed or adjustably set at an angle a relative to the impeller (16).

12. A method for the use of the arrangement (1) according to at least one of claims 1-11 , characterised in that the arrangement (1) is placed at least partially submerged in a fluid (3), after which the impeller (16) is caused to rotate by at least one drive unit (15) by which the impeller (16), from outside of the vessel, draws the fluid (3) out from the vessel (4) through the outlet (11), and in that an input flow of fluid (3) takes place through the inlet (10) whereby a vortex (27) consisting of fluid (3) and gas (2), or a mixture of gases, is formed in the inner chamber (5), the formed vortex (27) of which creates an addition of gas (2), or of a mixture of gases, to the fluid (3).

13. The method according to claim 12, characterised in that the fluid that is flowing in from the inlet channel (10) creates an upwardly moving vortex that transitions into a downwardly directed vortex (27) of fluid and gas.