NO320784B1 - Device for stirring and admixing air in a liquid and eliminating foam in a tank for treating said liquid - Google Patents

Description

The present invention relates to a device for stirring and mixing air into a liquid and eliminating foam in a tank or container where the liquid is treated, such as e.g. fatty waste products extracted from sewage effluents from cities or agro-related food industries.

As it is known, effluents from urban roofs that circulate in outlet pipes such as drains are collected in treatment stations where various beneficiation operations are carried out to purify them before returning to the natural medium.

This cleaning process produces by-products related to the cleaning such as grease, sludge....

Landfill sites are becoming less and less inclined to accept these types of products so that treatment plants must now be able to process them and limit them as much as possible.

Thus, grease is collected at the inlet to the cleaning station completely into a treatment tank, such as e.g. a biological degradation tank comprising a mechanical stirrer to stir the liquid.

Furthermore, the tank in its lower parts may include internal and injection manifolds for injecting pressurized air into the liquid to add air and enhance agitation of the liquid.

But this type of air supply and stirring device is more practically suitable for

liquids that are only lightly charged, i.e. of low viscosity, and its effectiveness drops rapidly for liquids that are charged especially with grease.

Furthermore, during the treatment of the liquid, such as e.g. fatty waste products, with this type of device a layer of foam is formed on the surface of the liquid which flies away and pollutes the surroundings so that it is necessary to provide means to eliminate the foam floating on the surface of the liquid during the treatment of the latter.

Until now, these means have consisted of agitators placed at the level of the liquid surface and adapted to smooth out the foam.

But these stirrers are not completely satisfactory and some of the foam flies away and pollutes the surroundings.

From EP 0 687 497, a decomposition tank is known in which the liquid is put into circulation by being led through a vertical pipe placed in the centre. Agitation is provided by dynamic means consisting of a central shaft which extends from the top of the tank down to the bottom where it is fixed in a wheel bearing. Rods are attached to the shaft which will stir the liquid when the shaft is set in rotation.

For mechanical reasons, there is a limitation on the length of the shaft, and thus on the depth in the tank. This limitation is very unfortunate because the efficiency of such a decomposition tank increases with increasing depth in the tank.

An aim of the invention is to avoid these disadvantages by proposing a device for stirring and adding air to a liquid, such as e.g. fatty waste products extracted from effluents from urban sewage or food industries, which allow, by means of simple means and low energy consumption, an effective treatment of this type of liquid and recovery of the foam on the surface of the liquid.

The objective of the invention can be achieved by a device which is characterized by the features that appear from the following description of the invention and the patent claims.

The invention therefore provides a device for agitating and adding air to a liquid and eliminating the foam in a tank for treating said liquid, characterized in that it comprises on the inside of the tank: - a vertical mantle extending for part of the height of the tank , which is closed at its upper end and open at its lower end, and where the lower end of the jacket defines together with the bottom of the tank a passage for the liquid, - a funnel arranged around the upper part of the jacket and which is connected to the jacket, where the upper end of the funnel defines, together with the wall of the tank, a free area for the passage of the liquid, - a first series of openings provided in the upper part of the mantle and placed at the level of the liquid on the inside of the funnel, - a second series of openings provided in the mantle and located above the bottom of the funnel, - a vertical shaft which rotates and is located inside the casing and extends from the upper end of the casing to the bottom of the funnel, - a main propeller l located on the free end of the shaft below the level of the funnel, - an anti-eddy flow agent located on the inside of the shroud below the propeller,

- means to regulate the liquid level in the funnel,

- means for injecting a gas under pressure into the mantle below the anti-eddy current means.

According to other features of the invention:

- is the tank insulated,

- the device comprises means for regulating the flow of liquid and foam which is sucked in by means of the propeller on the inside of the casing, - the device comprises means for carrying out a static agitation by means of cavitation of the liquid on the inside of the casing and located below the anti-eddy current means in said mantle, - the means for regulating the flow of liquid and foam sucked by said propeller is formed on the one side by a first sleeve placed around the mantle at the level of the first series of openings and, on the other side, by a second sleeve placed around said mantle at the level of the second series of ports, and where the position of the sleeves relative to the corresponding openings is vertically adjustable, - the means for performing a static agitation by means of cavitation are formed on one side of a vertical tube located inside of the jacket and extending from the bottom of the tank to below the anti-eddy current means and on the other side, superimposed static obstacles pl asserted on the inside of the mantle and which is attached to said pipe,. - the device comprises a second anti-eddy current means placed on the inside of the casing above the main propeller, the second anti-eddy current means is made up of at least two vertical plates each extending upwards in the form of a stiffening rib which extends up to the upper end of the casing,

- the device includes a liquid accelerator on the inside of the mantle,

- the device comprises means for supplying air to the surface of the liquid on the inside of the tank, - the device comprises a vortex pump for suction of surface liquid on the inside of the jacket, located above the second anti-eddy current means at the level of the first series of openings, - the device comprises a propeller having a single passage for suction of the liquid on the inside of the casing, located above the second anti-eddy current means at the level of the first series of openings, - the device comprises a propeller having two passages for suction of liquid on the inside of the casing, located above it second anti-eddy current means at the level of the first series of openings.

Further features and advantages of the invention will become apparent during the following description with reference to the accompanying drawings, where: fig. 1 is a schematic side view of a tank for treating a liquid equipped with a first embodiment of a device for stirring and supplying air to the liquid according to the invention,

fig. 2 is a section taken along line 2-2 in fig. 1,

fig. 3 is a schematic view of a tank for treating liquid equipped with a second embodiment of a device for stirring and supplying air to the liquid according to the invention,

fig. 4 is a view taken along line 4-4 in fig. 3,

fig. S is a schematic partial section of a third embodiment of a device for stirring and supplying air to the liquid according to the invention,

fig. 6 is a schematic view of a liquid accelerator for the device for stirring and supplying air according to the invention,

fig. 7 is a schematic diagram of means for supplying air to the surface of the liquid,

fig. 8 is a schematic partial section of a fourth embodiment of a device for stirring and supplying air to the liquid according to the invention,

fig. 9 is a schematic view on a larger scale of the vortex pump in the fourth embodiment of the device according to the invention,

fig. 10 is a view taken along the line. 10-10 in fig. 9,

fig. 11 is a schematic partial view of a fifth embodiment of the device for stirring and supplying air to the liquid according to the invention,

fig. 12 is a view taken along the line 12-12 in fig. 11,

fig. 13 is a schematic partial view of a sixth embodiment of a device for stirring and supplying air to the liquid according to the invention,

fig. 14 is a view taken along the line 14-14 in fig. 13.

Shown in fig. 1 and 3, a tank or container 1 is equipped in its upper part with an inlet 2 for a liquid 3 to be treated, such as e.g. fatty effluents extracted from municipal sewage effluents.

The treating tank 1 is covered on its outer side with an insulation 4 and comprises a device, indicated by the general reference number 10, for stirring and supplying air to the liquid and eliminating the foam.

The device 10 according to the invention placed on the inside of the tank 1, comprises a vertical mantle 11 which extends for part of the height of the tank 1.

The upper end 1 la of the mantle 11 is closed by means of the plate 12, and the lower end of the mantle 11 is open and together with the bottom of the tank 1 defines a passage 13 for the liquid 3.

The device 10 further comprises an upwardly diverging funnel 14, the upper end of which, together with the wall of the tank 1, defines a free area IS for the passage of the liquid 3, the lower end of which is connected to the casing 11 at a certain distance from the upper end of the casing 11.

The assembly comprising the mantle 11 and the funnel 14 is attached to the inside of the tank

1 by suitable means, such as e.g. stiffeners 16 which define between them passages for the liquid 3.

The mantle 11 comprises a first series of openings 17 which are evenly positioned along the circumference of the mantle 11 at the same level as the liquid in the funnel 14.

This mantle 11 is further provided with a second series of openings 18 which are placed evenly along the circumference of the mantle 11 at level with the bottom of the funnel. The device 10 is also provided with means for sucking liquid and foam on the inside of the jacket 11 through the openings 17 and 18, and is designed by means of a vertical shaft 19 placed on the inside of the jacket 11 which extends from the upper end of the jacket 11 to the bottom of the funnel 14 and by means of a main propeller or screw 20 placed on the free end of the shaft 19 below the bottom of the funnel 14.

The diameter of the main propeller 20 is somewhat smaller than the inner diameter of the casing 11.

The shaft 19 and the propeller 20 are rotated by means of a motor speed reduction unit 21 which is attached to the plate 12 which closes the upper end of the casing 11.

The device 10 is equipped with means to regulate the flow of liquid and foam which is sucked by the main propeller 20 on the inside of the casing 11 through the openings 17 and 18.

These regulating means comprise on the one hand a first sleeve 22 placed around the mantle 11 at the level of the first series of openings and on the other hand a second sleeve 23 placed around the mantle 11 at the level of the second series of openings 18.

The position of each sleeve 22 and 23 relative to the openings 17 and 18 is vertically adjustable by suitable level fixing means (not shown).

An anti-eddy current means 24 is placed on the inside of the casing 11 below the propeller 20 to prevent rotation of the liquid 3 in the casing 11.

As shown in fig. 2, this anti-eddy current means 24 is formed by three vertical plates 24a placed at an angle of 120° to each other on the inside of the mantle 11.

The device 10 is also equipped with means for regulating the level of the liquid 3 in the funnel 14 which comprises an overflow pipe 25 placed on the inside of the funnel 14 in a vertically adjustable position.

In the second embodiment shown in fig. 3, the device 10 comprises means 30 for effecting a static stirring by means of cavitation of the liquid 3 on the inside of the mantle 11 and which is placed below the anti-eddy current means 24 in the mantle.

As shown in fig. 3 and 4, the means 30 for the static stirring by means of cavitation of the liquid 3 comprise, on the one hand, a vertical tube 31 placed on the inside of the jacket 11 and which extends from the bottom of the tank 1 to below the anti-eddy current means 24 and on the on the other hand, superimposed static obstacles 32 placed on the inside of the mantle 11 and placed on the pipe 31.

The pipe 31 is attached to the bottom of the tank 1 by suitable means.

The static obstacles 32 define with the help of the inner wall of the mantle 11 passage for circulation of the liquid.

As shown in fig. 3, the static obstacles 32 are distributed along the pipe 31 on the one side below the anti-eddy current means 24 and on the other side the lower part of the mantle 11.

E.g. the tube 31 comprises in its upper part below the anti-eddy current means 24 two overlying static obstacles 32 and in the lower part of the mantle 11 also two overlying static elements 32.

In a variant, the static obstacles 32 can be evenly distributed along the entire part of the tube 31 placed on the inside of the jacket 11.

In the embodiment shown in fig. 3, the static barriers 32 are formed by bowl-shaped objects where the concavity points downwards towards the bottom of the tank 1.

In a variant, the static barriers 32 can be formed by discs.

Finally, the device 10 comprises means 33 for injecting gas under pressure, such as e.g. air in the mantle 11.

These injection means 33 are formed by at least one tube 34 which has an opening inside the mantle 11, e.g. at a level below the static element 32 which is distributed in the upper part of the tube 31.

The device described above works in the following way.

The liquid 3 to be treated is poured through the inlet 2 in the tank 1 up to a level above the upper edge of the funnel 14.

This liquid 3 is also poured into the funnel 14.

The engine speed reduction unit 21 rotates the shaft 19 which in turn rotates the main propeller 20.

At the same time, pressurized gas is injected into the casing 11 through the pipes 34.

The rotation of the main propeller 20 causes suction of the liquid 3 into the casing 11 through the openings 17 and 18 so that this liquid 3 is continuously circulated from the top to the bottom in the casing 11, then passes through the space 13 and circulates from the bottom to the top between the casing 11 and the inner wall to tank 1 etc.

The anti-eddy current means 24 prevent the rotation of the liquid in the jacket 11 below the propeller 20.

The level of the liquid 3 in the funnel 14 is below the level of the liquid in the tank 1 and this liquid level in the funnel 14 is regulated by means of the overflow pipe 25 so that it is mainly halfway up the height of the openings 17.

Furthermore, due to the suction created by the propeller on the inside of the mantle 11, the liquid level in the mantle 11 is below the liquid level in the funnel 14.

The air that is driven inside the casing 11 by means of the rotation of the propeller 20 and the gas that is injected under pressure into the casing 11 forms gas bubbles which are dispersed in the liquid 3 in the casing 11 under the effect of the rotation from the propeller 20.

During the circulation of the liquid 3 in the mantle 11, a cavitation effect is formed under each of the static obstacles 32 which promotes stirring and the supply of air in the liquid 3. . These obstacles 32 have the advantage that they are static at the same time as they promote stirring and air supply to the liquid in the mantle 11 and prevent the collection of fibrous substances 5 on the inside of the mantle 11.

In this way, the liquid 3 is stirred and the gas bubbles are divided into microbubbles which promote the dispersion of the gas and, as a consequence, the supply of air to the liquid 3.

Between the inner wall of the tank 1 and the jacket 11, the gas bubbles accelerate the ascent of the liquid and promote the circulation of this liquid in the tank 1, thus improving the efficiency.

Thus, the liquid to be treated will be passed several times through the mantle 11 and thus undergo several oxygenation treatments.

The flow of liquid 3 can be regulated by pushing the sleeves 22 and 23 relative to the openings 17 and 18.

The stirring of the liquid 3 by means of the propeller 20 and the static barrier 32 causes foam to form on the surface of the liquid 3 in the tank 1.

The rotation of the propeller 20 on the inside of the jacket 11 produces a pumping effect at the level of the surface of the liquid 3 in the funnel 14, suction of the foam floating on the surface of the liquid and falling in the level of the latter in the jacket 11.

As a consequence, the foam is collected, drowned in and mixed with the liquid 3 in the tank 1 so that it is possible to progressively eliminate it.

The position of the sleeves 22 and 23 relative to the openings 17 and 18 regulates the flow of liquid and foam 5 which is sucked on the inside of the mantle 11 by means of the propeller 20.

The choice of main propeller 20 and rotation speed of the latter allows an adaptation of the energy consumption according to the liquid to be treated.

In the case where the device according to the invention does not include static elements 32 as shown in fig. 3, turbulence naturally forms on the inside of the mantle 11.

But the efficiency is low, which is only suitable for liquids that are lightly charged.

The static barriers 32 promote agitation of the liquid by cavitation and this improves the efficiency of the device.

In a variant, the static stirring means with cavitation effect form static obstacles which are attached to the inner wall of the mantle 11 and which define an axial passage for the circulation of the liquid 3.

These static obstacles are evenly distributed along the entire portion of the mantle 11 under the anti-eddy current means 24 or on the inside of the mantle 11, on one side under the anti-eddy current means 24 and on the other side in the lower part of the mantle 11.

In this case too, the static obstacles are formed, e.g. of bowl-shaped objects with a concavity directed towards the bottom of the tank 1 or by means of disks.

In a third embodiment shown in fig. 5, the device comprises a second anti-eddy current means 40 placed on the inside of the mantle 11 above the main propeller 20.

This second anti-eddy current means 40 comprises at least two vertical plates 40a each extending upwards along a reinforcing rib 41 which extends to the upper end of the mantle 11.

Preferably, the other anti-eddy current means 40 are formed by four vertical plates 40a evenly distributed along the inside of the mantle 11 and where each extends upwards in the form of a reinforcing rib 41.

In another embodiment shown in fig. 6, the device comprises a liquid accelerator on the inside of the mantle 11.

This fluid accelerator comprises a second propeller 45 located above the second anti-eddy current means 40 and fixed to rotate with the shaft 19.

The second propeller or screw 45 has a pitch angle which is directed in the same direction as the pitch angle of the main propeller or screw 20.

Furthermore, the liquid accelerator further comprises an anti-eddy current means 46 placed above the second propeller 45 on the inside of a cylindrical channel 47.

The channel 47 is attached to the inner edge of the reinforcement ribs 41 so that it defines together with the mantle 11 and between the reinforcement ribs 41 passages

. 48 for the liquid.

The second propeller 45, the anti-eddy current means 46 and the channel 47 are located between the two series of openings 17 and 18 which are provided, in this embodiment, with means to regulate the flow rate of the liquid 3 and the flow of the foam sucked inside the jacket 11 .

The rotation of the main propeller 20 causes suction of liquid 3 into the casing 11 through the openings 17 and 18 so that this liquid 3 is continuously circulated downwards in the casing 11.

Furthermore, due to the rotation of the second propeller 45, the suction of the liquid 3 into the casing 11 through the openings 17 and 18 is accelerated and part of the liquid rises through the passages 48 provided between the casing 11 and the channel 47 which further increases this acceleration phenomenon of the liquid in the mantle 11.

Also in this case, the regulation of the level of the liquid 3 in the jacket 11 is achieved by means of the position of the sleeves 22 and 23 relative to the openings 17 and 18.

The anti-eddy current means 46 prevent rotation of the liquid in the channel 47.

This embodiment is particularly suitable for products that have a particular tendency to foam.

Due to the acceleration of the suction of the liquid 3 on the inside of the channel 47 and the recirculation of part of this liquid in the passages 48, the foam floating on the surface of the liquid 3 is also sucked on the inside of the channel 47.

In another embodiment shown in fig. 7, the device comprises means for supplying air to the surface of the liquid 3 in the tank 1.

As shown in fig. 7, the means for supplying air to the surface of the liquid 3 is formed by a second propeller or screw 50 placed above the second anti-eddy current means and fixed to rotate with the shaft 19.

This second propeller 50 has a pitch angle that is inverted in relation to the pitch angle of the main propeller 20.

The means for supplying air to the surface of the liquid 3 also comprise anti-eddy current means 51 located below the second propeller 50 and on the inside of a cylindrical channel 52.

The channel 52 is attached to the inner edges of the reinforcement ribs 48 so that they define together with the mantle 11 and the said reinforcement ribs 48 passages 55 for the liquid 3.

The second propeller 50 and anti-eddy current means 51 are located between the two series of openings 17 and 18, and the channel 52 extends substantially from the middle part of the first series of openings 17 to the upper end of the second series of openings 18.

A cover plate 53 is mounted on the shaft 19 above the upper edge of the channel 52.

The vertical position of the cover plate 53 is adjustable to define together with the upper edge of the channel 52 an adjustable passage 54.

The rotation of the main propeller 20 sucks liquid 3 through the openings 17 and 18 so that this liquid circulates upwards in the casing 11.

Thus, part of the liquid 3 will be sucked into the mantle 11 through the opening 18 and another part of the liquid will be sucked through the opening 17 and circulate downwards in the passages 55 defined between the channel 52 and the mantle 1.1.

Furthermore, due to the fact that the pitch angle of the second propeller 50 is inverted in relation to the pitch angle of the main propeller 20, part of the liquid will be sucked into the channel 52 in an upward direction and sprayed into the air above the surface of the liquid 3 on the inside of the funnel 14 when it passes through passage 54.

Thus, spraying a part of the liquid will allow mixing of air on the surface of the liquid 3 and, as a consequence, a reduction in the formation of foam on this surface.

The anti-eddy current means 51 prevent rotation of the liquid in the channel 52 above the second propeller 50.

Also in this design example, the flow of the liquid 3 in the jacket 11 can be regulated by displacing the sleeves 22 and 23 relative to the openings 17 and 18.

In an embodiment shown in fig. 8-10, the device comprises a vortex pump 60 for sucking the surface liquid into the mantle 11.

This vortex pump 60 is located above the second anti-eddy current means 40 and level with the first series of openings 17.

This vortex pump 60 is driven into rotation by means of the shaft 19, and comprises on one side a circular plate 61 attached to the shaft 19 and which is provided on its upper side with radial and vertical blades 62, and on the other side a channel 63 attached to the upper edge of the leaves 62.

The assembly comprising the plate 61, the blades 62 and the channel 63 is fixed to the shaft 19 by means of a sleeve 61a which has an adjustable position on the shaft 19.

The sleeve 61a is attached to the shaft 19 by e.g. a fixing screw (not shown).

As shown in Figs. 8 and 9, the upper edge of blades 62 is provided with a ring 64 extending outwardly from channel 63.

The channel 63 extends from a position near the top of the tank 1 mainly in the middle part to the first series of openings 17 to the upper edge of the blades 62.

The channel 63 defines an internal passage 65 which communicates in its lower part with the interior of the mantle 11 through annular passages 66 formed between blades 62 and between the ring 64 and the plate 61.

The channel 63 is preferably conical and tapers towards the upper part of the tank 1 as shown in fig. 9.

In one variant, the channel 63 can be cylindrical.

The blades 52 are flat or curved and preferably in a number of three and are evenly distributed along the circumference of the plate 61 as shown in fig. 10.

The rotation of the main propeller 20 causes suction of liquid 3 into the casing 11 through the openings 17 and 18 so that this liquid 3 is continuously circulated downwards in the casing.

Furthermore, the rotation of the vortex pump 60 driven by the shaft 19, i.e. the rotation of the assembly comprising the plate 61, the blades 62 and the channel 63, will cause a suction of surface liquid 3 into the passage 65 so that this liquid then passes through the annular passages 66 and becomes reinjected into tank 1.

In this embodiment, the regulation of the flow rate by means of the sleeves 22 and 23 on the inside of the jacket 11 is unnecessary.

This embodiment is particularly suitable for products that have a great tendency to form foam due to the fact that foam floating on the surface of the liquid 3 is sucked in by the vortex pump 60 so that this foam can be quickly and effectively eliminated.

In one embodiment shown in fig. 11 and 12, the device comprises a single-passage propeller 70 for sucking the liquid 3 into the casing 11.

This single passage propeller 70 is positioned above the second anti-eddy current means 40 at the level of the first series of openings 17.

The single-passage propeller 70 is rotated by means of the shaft 19 and comprises, on the one hand, a circular plate 71 attached to the shaft 19 and which is placed above the level of the liquid 3 in the tank 1, and on the other hand, a vertical plate 72 down in the fluid 3 which forms a spiral and is attached to the lower surface of the plate 71 around the shaft 19.

As shown more particularly in fig. 12, the plate 72 defines a lateral inlet 73 for the liquid extending through the height of the plate 72, a vertical passage 74 for the downward circulation of this liquid and a lower outlet 75 for the liquid.

The assembly comprises the plate 71 and the vertical plate 72 and is fixed to the shaft 19 by means of a sleeve 71a which has a vertically adjustable position on the shaft 19.

For this purpose, the sleeve 71a is attached to the shaft 19 by means of e.g. a fixing screw (not shown).

The inner edge of the vertical plate 72 includes a vertical deflector 76 which is inclined in the direction towards the center of the spiral formed by the plate 72.

Furthermore, the distance between the plate 72 and the axis of the shaft 19 is progressively decreasing as shown in fig. 12.

The rotation of the single passage propeller 70 driven by the shaft 19, i.e. the rotation of the assembly comprising the plate 71 and the plate 72, in the direction indicated by the arrow in fig. 12, causes suction of liquid into the interior of the plate 72 through the lateral opening 73.

This liquid is stirred inside the vertical passage 74, circulates downwards in the latter and is ejected into the casing through the lower outlet 75.

The deflector 76 improves the agitation of the liquid in the vertical passage 74 and prevents the return of the liquid through the lateral inlet 73.

In a final embodiment shown in fig. 14, the device comprises a double-passage propeller 80 for sucking liquid 3 into the casing 11.

This double passage propeller 80 is located above the second anti-eddy current means 40 and level with the first series of openings 17.

The double-passage propeller 80 is driven in rotation by the shaft 19 and comprises, on the one hand, a circular plate 81 attached to the shaft 19 and which is arranged above the level of the liquid 3 in the tank 1, and on the other hand, two vertical plates 82 and 83 down in the liquid 3.

The vertical plates 82 and 83 are attached to the lower surface 80 and are both in the form of two half-shells which are opposite and offset in relation to each other as shown in fig. 14.

The two plates 82 and 83 define two lateral inlets 84 and 85 for the liquid, two passages 86 and 87 for the downward circulation of this liquid and a lower outlet 88 for the liquid.

The assembly comprising the plate 81 and the vertical plates 82 and 83 is fixed to the shaft 19 by means of a sleeve 81a which has an adjustable vertical position on the shaft 19.

The sleeve 81 is attached to the shaft 19 by means of e.g. a fixing screw (not shown).

As shown more particularly in fig. 14, the edge of each plate 82 and 83 facing the passages 86 or 87 defined by the other plate includes a vertical deflector 89 and 90 respectively.

The rotation of the double passage propeller 80, driven by the shaft 19, i.e. the rotation of the assembly comprising the plate 81 and the two vertical plates 82 and 83 in the direction indicated by the arrow in fig. 14, causing suction of liquid 3 through the openings 17.

This liquid passes through the lateral inlets 84 and 85, is agitated on the inside of the passages 86 and 87 and circulates downwards in these passages 86 and 87 and is then discharged into the casing 11 through the lower outlet 88.

The deflectors 89 and 90 increase the agitation of the liquid in the passages 86 and 87 and prevent the liquid from flowing back to the lateral inlets 84 and 85.

In the last two embodiments, the regulation of the flow of liquid by means of the sleeves 22 and 23 in the jacket 11 is unnecessary and these last two embodiments are more particularly used in the case where the liquid level in the tank 1 is variable.

To improve the flow of the fluid to the single-passage propeller 70 or the double-passage propeller 80, a pump propeller (not shown) can be placed on the shaft 19 below the single-passage propeller or below the double-passage propeller.

The device according to the invention can be used e.g. for the treatment of water, urban effluents, industrial waste water, fats by biodegradation, waste substances, livestock waste products and generally any biodegradable industrial product.

The device according to the invention can also be used e.g. in the ozonation of water using ozonated gas with or without a catalyst, in the stabilization of sludge, or can be used in a thermophilic treatment or for liquids charged with substances in suspension, for example, organic or mineral substances.

The device according to the invention can also be used as a reactor that operates with a fluidized or moving bed.

The device according to the present invention also has the advantage of treating the liquid and at the same time progressively eliminating the foam that floats on the surface of the liquid in the treated tank and thus ensuring that this foam does not pollute the surroundings.

Claims (33)

1. Device for stirring and supplying air to a liquid and eliminating the foam in a tank (1) for treating said liquid, comprising on the inside of the tank (1): - a vertical mantle (11) extending along part of the height of the tank (1) and which comprises at least one first opening (17, 18) which provides an inlet for the liquid (3) in the upper part, and at least one second opening which provides an outlet (13) for the liquid (3) the bottom of the tank, - a funnel (14) placed around the upper part of the mantle (11) and which is connected to the mantle (11), where the upper end of the funnel (14) defines together with the wall of the tank (1) a free area (15) for the passage of the liquid (3), - a main propeller (20) placed on the inside of the mantle (11) under the bottom of the funnel (14), - a vertical shaft (19) which is rotated, and which extends on the inside of the mantle (11) above this propeller (20) and which rotates, the latter, - an anti-eddy current means (24) placed on the inside of the mantle (11) under said p ropell (20), - means (33) for injecting a gas under pressure into the mantle (11), below the anti-eddy current means (24), characterized in that it also includes means for stirring the liquid (3) by means of turbulence on the inside of the mantle (11) below the anti-eddy current means, either by static stirring means (31, 32) or by turbulence forming naturally on the inside of the mantle (11 ). 2. Facility according to requirement 1, characterized in that it comprises: - a first series of openings (17) provided in the upper part of the mantle (1), and placed at the level of the liquid (3) in the funnel (14), - a second series of openings (18) provided in the mantle (11) above the bottom of the funnel (14), and • means (25) for regulating the level of the liquid (3) in the funnel (14). 3. - Device according to requirement 2, characterized in that it comprises means (22, 23) for regulating the flow of liquid (3) and foam which is sucked by the propeller (20) into the mantle (11). 4. Device according to requirement 3, characterized in that the means for regulating the flow of liquid (3) and foam which is sucked in by means of the propeller (20) is formed, on one side, by a first sleeve (22) placed around the mantle. (11) at the level of the first series of openings (17), and on the other hand, of a second sleeve (23) placed around said mantle (11) at the level of the second series of openings (18), and where the position of the said sleeves (22, 23) are vertically adjustable in relation to the corresponding openings (17,18). 5. Device according to any one of the preceding claims, characterized in that the means for effecting a static stirring by means of cavitation are formed on one side of a vertical tube (31) placed on the inside of the mantle (11) and which extends from the bottom of the tank (1) to below the anti-eddy current means (24) and on the other side of static barriers (32) arranged one above the other on the inside of the jacket (11) and which is attached to the pipe (31). 6. Device according to requirement 5, characterized in that the static obstacles (32) together with the inner wall of the mantle (11) define passages for circulation of the liquid (3). 7. Facility according to requirements 5 and 6, characterized in that the static obstacles (32) are evenly distributed along it the part of the tube (31) that is on the inside of the mantle (11). 8. Device 1 according to claims 5 and 6, characterized f in that the static obstacles (32) are placed on the pipe (31), on the one hand, under the anti-eddy current means (24), and on the other hand, in the lower part of the mantle (11). 9. Device according to requirement 5, characterized in that the static stirring means which apply turbulence are formed by static barriers placed on the inner wall of the mantle (11) and which define an axial passage for circulation of the liquid (3). 10. Device according to claim 9, characterized in that the static obstacles are evenly distributed along the entire part of the mantle (11) which is below the anti-eddy current means (24). 11. Device according to claim 10, characterized in that the static obstacles are arranged on the inside of the mantle (11) on one side under the anti-eddy current means (24) and on the other side in the lower part of the mantle (11).. 12. Device according to any one of claims 5-11, characterized in that the static obstacles are formed by bowl-shaped objects (32) where the hollow cavity is directed downwards towards the bottom of the tank (1). 13. Device according to any one of claims 5-11, characterized in that the static barriers are formed by disks. 14. Device according to any of the preceding claims, characterized in that the tank (1) is insulated. 15. Device according to any one of the preceding claims, characterized in that the means for regulating the level of the liquid (3) in the funnel (14) consists of an overflow pipe (25) placed on the inside of the funnel (14) in a position which is vertically adjustable. 16. Device according to any one of the preceding claims, characterized in that it comprises a second anti-eddy current means (40) placed on the inside of the mantle (11) above the main propeller (20), where the second anti-eddy current means (40) is formed by at least two vertical plates (40a) each extending upwards in the form of a stiffening rib (41) which extends up to the upper end of the mantle (11). 17. Device according to any one of the preceding claims, characterized in that it comprises a liquid accelerator (45, 46, 47) on the inside of the mantle (11). 18. Device according to any one of the preceding claims, characterized in that the liquid accelerator is formed by, on one side, a second propeller (45) placed above the second vortex means (40), which is connected to rotate with the shaft (19), and having a pitch angle oriented in the same direction as the pitch angle of the main propeller (20), and on the other hand, an anti-eddy current means (46) located above the second propeller (45 ) on the inside of a cylindrical channel (47) attached to the reinforcement ribs (41), and where the second propeller (45), the anti-eddy current means (46) and the channel (47) are located between the two series of openings (17, 18) . 19. Device according to any one of claims 1-16, characterized in that it comprises means (50, 51, 52) for supplying air to the surface of the liquid in the tank (20). 20. Device according to any one of claims 1-16 and 19, characterized in that the means for supplying air to the surface of the liquid comprise, on the one hand, a second propeller (50) placed above the second anti-eddy current means (40 ), which is connected to rotate with the shaft (19) and which has a pitch angle that is inverted in relation to the pitch angle of the main propeller (20), and on the other hand, an anti-eddy current means (51) located above the second propeller ( 50) on the inside of a cylindrical channel (52) attached to the reinforcement ribs (41), where the second propeller (50) and the anti-eddy current means (51) are located between the two series of openings (17, 18) and where the channel (52 ) extends substantially from the middle part of the first series of openings (17) to the upper edge of the second series of openings (18). 21. Device according to claim 20, characterized in that a cover (53) is mounted on the shaft (19) above the upper edge of the channel (52) and which defines with said upper edge an adjustable passage (54). 22. Device according to any one of claims 1-3 and 5-16, characterized in that it comprises a vortex pump (60) for sucking surface liquid into the mantle (11) which is placed above the second anti-eddy current means (40) f level with the first series of openings (17). 23. Device according to claim 22, characterized in that the vortex pump (60) comprises, on the one hand, a circular plate (61) connected to rotate with the shaft (19) and which is equipped on its upper side with radial and vertical blades (62), and on the other hand , a channel (63) located on the upper edge of the blades (62) and extending from a position near the upper end of the tank (1) mainly from the middle part to the first series of openings (17) to said upper edge to the leaves (62). 24. Device according to claim 23, characterized in that the channel (63) is conical and tapers towards the upper end of the tank (1). 25. Device according to claim 23, characterized in that the channel (63) is cylindrical. 26. Device according to claim 23, characterized in that the blades (62) are flat or curved. r 27. Device according to any one of claims 1-3 and 5-16, characterized in that it comprises a single-pass propeller (70) for sucking liquid (3) into the jacket (11) which is placed above the second anti-eddy current means (40) at the level of the first series of openings (17). 28. Device according to claim 27, characterized in that the single-passage propeller (70) comprises, on the one hand, a circular plate (71) connected to rotate with the shaft (19) and which is placed above the level of the liquid (3) in the tank (1), and on another side, a vertical plate (32) in the liquid (3) which forms a spiral and which is attached to the lower end of said plate (71) around the shaft (19), and where the plate (72) defines a lateral inlet (73) for the liquid, a vertical passage (74) for downward circulation of the liquid and a lower outlet (75). for the liquid. 29. Device according to claim 28, characterized in that the inner edge of the vertical plate (72) comprises a vertical deflector (76) which is angled in the direction towards the center of the spiral. 30. Device according to any one of claims 1-3 and 5-16, characterized in that it comprises one double t-passenger propeller (80) for. suction of liquid (3) into the jacket (11) which is placed above the second anti-eddy current means (40) at the level of the first series of openings (17). 31. Device according to claim 30, characterized in that the double t-passage propeller (80) comprises, on one side, a circular plate (81) connected to rotate with the shaft (19) and which is placed above the level of the liquid (3 ) in the tank (1), and on the other hand, two vertical plates (82, 83) in the liquid (3) which are placed on the lower surface of said plate (81) and which have the shape of two half-shells arranged opposite and offset to each other, because the plates (82^ 83) define two lateral inlets (84, 85) for the liquid, two vertical passages (86, 87) for downward circulation of the liquid. and a lower outlet (88) for the liquid. 32. Device according to claim 31, characterized in that the edge of each plate (82, 83) located in opposing relation to the passage (86, 87) defined by the other plate, includes a vertical deflector (89, 90). 33. Device according to claim 27 or 30, characterized in that a pump propeller (19) is placed on the shaft (19) below the single-passage propeller (70) or the double-passage propeller (80).