EP1945337B1 - Eddy chamber - Google Patents

Abstract

The invention relates to an eddy chamber for generating turbulence in a medium flowing through the chamber, comprising an inlet opening, an outlet opening and at least two constrictions in the cross-section thereof. In the region of the constrictions, the inner profile of the eddy chamber has the form of wave crests (10, 12, 25, 27, 30) in section parallel to the longitudinal axis thereof. According to the invention, the mixing may be improved and the pressure drop held small, whereby the angle to the longitudinal axis (z) in the direction of the outlet opening (15, 31) at the inflection points (12a, 25a, 27a, 30a) on the flanks of at least two wave crests (10, 12, 25, 27, 30) facing the inlet opening (9, 23) is larger. The invention further relates to a device for the enrichment of a liquid medium with a gaseous medium, in particular for the introduction of oxygen in water treatment, comprising an injector (3) for the introduction of gas, an eddy chamber (2) arranged before the injector (3) with at least one constriction in the cross-section thereof and an eddy chamber (4) after the injector (3) with at least one constriction in the cross-section thereof.

Description

The invention relates to a vortex chamber for generating turbulence in a flowing medium, with an inlet opening, an outlet opening and at least two constrictions in its cross section, wherein in the region of the constrictions, the inner profile of the vortex chamber has the shape of wave crests in section parallel to its longitudinal axis ,

The invention further relates to a device for enriching a liquid medium with a gaseous medium, in particular for supplying oxygen in the water treatment, comprising an injector for the gas supply, a vortex chamber upstream of the injector with at least one constriction in its cross section and a vortex chamber downstream of the injector with at least one constriction in its cross section, wherein in the region of the constriction, the inner profile of the downstream vortex chamber has the shape of a wave crest parallel to its longitudinal axis in section

Such devices are preferably used in wastewater technology for the purification of water and drinking water treatment. In this case, the water is supplied via an injector ozone, which should oxidize with pollutants contained in the water, solid components, suspended particles, etc. However, such a device is generally suitable for adding a gas to a liquid to thereby effect a desired reaction in the liquid medium.

The DE 43 14 507 C1 discloses an injector or mixer for flotation devices, such as fiber suspensions, consisting of two mutually facing injector plates. These have repeated elevations in the direction of flow, causing constrictions of the flow cross-section. In one embodiment, the bumps towards the outlet end are getting smaller, while the distance between adjacent bumps is correspondingly larger. It has been found that such an arrangement does not provide optimal mixing results and in particular the pressure drop between inlet and outlet remains relatively large.

The DE 34 22 339 A1 discloses a method for mixing fluids in which a ribbon-shaped flat jet is expelled from a slot die and combined with a second flat jet. In the downstream in the flow direction mixing tube changes the diameter of the flow cross section through gradual constrictions and extensions at fixed distances in the axial direction. Similar to the injector of the previous document, the non-optimal mixing and the pressure drop are disadvantageous.

The EP-A-0256965 discloses a method and apparatus for hydrodynamic mixing.

The US 6,673,248 B2 discloses a method for purifying water by eliminating bacteria contained therein by supplying ozone into an injector. Downstream of the injector is a tubular mixing chamber, the cross-section of which is greatly reduced locally by baffles arranged normal to the direction of flow. These baffles are said to cause turbulence, which increase the mixing of the water flowing through the pipe with the ozone. In addition, it is provided to arrange an arcuate obstacle behind the central opening of one of the baffles. A view through the pipe along the pipe axis is denied due to the baffles and obstacles.

With such a device, however, the mixing of the water with the ozone remains inadequate. On the one hand, this is due to the fact that the baffles only represent obstacles and lead to a spatial extension of the flow path to the outlet of the mixing chamber. Turbulence is caused only locally and limited to a certain size. A comprehensive and even distribution of ozone in the water and, more importantly, the direct contact with the constituents to be oxidized (solid constituents, suspended particles, etc.) is hardly produced.

The analysis of existing devices for ozone enrichment of liquids has shown that the transition of the gas into the liquid only reaches an efficiency of about 15%. In other words, this means that of the gas provided, only 15% of the substances to be oxidized enter the liquid, so that the result after a single oxidation process is far from satisfactory and ozone must be supplied in several consecutive cascades. The required system size or the number of system components are enormous and lead to high operating costs.

Another disadvantage in the prior art, including in the US 6,673,248 B2 disclosed invention, is that lying in the flow cross-section baffles greatly reduce the flow velocity and a huge overpressure at the inlet of the device is necessary to obtain a reasonably efficient flow at the outlet of the mixing chamber. At an inlet-side pressure of about 5 bar is usually expected with an outlet-side pressure of 1-1.5 bar, which represents a huge pressure drop.

There is thus a need for a device for the enrichment of liquids with gases, in which the oxidation of the substances to be treated in the liquid proceeds satisfactorily in a single process step. With a higher degree of efficiency, expensive system components can also be saved. At the same time, the device should be operable with a smaller pressure gradient between inlet and outlet and thus allow small pumping capacities.

According to the invention, these objectives are achieved with a swirl chamber of the type mentioned above in that, in the direction of the outlet opening, the inclinations to the longitudinal axis in the turning points at the flanks facing at the inlet opening become larger at least two wave crests.

By this measure, vortices are induced in the medium, without the flow being significantly slowed or impaired by the vortex chamber. The inventive design of the constriction spatially evenly distributed vortices, an elongation of the molecular structure, an expansion of spaces in the medium and a mechanical separation of substances are increasingly achieved. Due to the interaction of these effects, the oxygen actually reaches the components of the liquid medium that are to be oxidized. The efficiency, which is measured on the actual oxidation, achieved with the inventive measure up to 70% and in particular embodiments, even more.

Thus, optimal mixing is only achieved by the measure according to the invention, because eddies of different sizes and thickness are produced by the different degrees of rise, so that a thorough mixing is ensured both in macroscopic and microscopic dimension. The fact that the inclinations increase in the direction of the outlet opening has the positive influence that the pressure drop along the vortex chamber can be kept low. These advantages are complemented by the synergistic effect that results from the fact that in the flow direction, ie the direction of the pressure drop, the slopes become larger, so that efficient vortex formation is still ensured at these points.

According to the above objects are achieved with a device of the type mentioned in that in the region of the constriction, the inner profile of the upstream vortex chamber in section parallel to its longitudinal axis in the form of a wave crest, and that at least two wave crests are provided in at least one vortex chamber, wherein in Direction to the outlet opening of the vortex chamber towards the inclinations to the longitudinal axis in the turning points at the side facing the inlet flanks of at least two wave crests are larger.

By this measure, a vortex chamber upstream of the injector, the liquid experiences increased turbulence even before the direct contact with the ozone, whereby the molecular structure in the liquid is greatly changed. The extension of the cross-section following the constriction in the vortex chamber results in stretching of the molecular complex and expansion of interstices. The speed of the media flow is proportional to the cross-sectional enlargement. Due to the change in cross section in particular strong, inwardly rotated vortices cause a loosening of the molecules. Particles that interact only through hydrogen bonds and van der Waals forces are thus loosened and some mechanical separation of substances occurs. Such prepared in the upstream vortex chamber medium provides in the subsequent injector an optimal partial pressure for the uptake of ozone.

The negative pressure subsequently caused by a nozzle and thus by an increased flow velocity in the injector causes the suction and entrainment of the gaseous medium. In the subsequent second vortex chamber, the ozone reaches the molecules to be oxidized uniformly in the water. For this purpose, the profile according to the invention is responsible, can be generated by the in a single vortex chamber different sized and strong vortex.

In one embodiment, the entire inner profile along the longitudinal axis is corrugated, whereby the principle of the invention is extended to the entire vortex chamber. By means of several peaks with intervening valleys, an optimal, comprehensive vortex formation maintained along the entire vortex chamber can be created.

In a particular embodiment, at least in a wave crest the inclinations in its inflection points with respect to the longitudinal axis between 25 ° and 55 °. By this measure, in conjunction with the flow area, an optimal ratio between vortex formation to decelerate the medium can be achieved.

In a further embodiment, at least two wave crests are provided, wherein in the direction of the outlet opening, the inclinations in their inflection points at the flanks of the wave crests facing the outlet opening become smaller relative to the longitudinal axis. As a result, the respective expansion in the direction of the exit is reduced or delayed, whereby already excited vortex of a certain size after the respective wave crests can be maintained longer.

In one embodiment, the cross section in the region of at least one wave crest is less than 40% of the maximum cross section of the vortex chamber. This constriction allows a comprehensive and spatially homogeneous formation of vertebrae in the flowing medium.

In the following the invention will be explained in more detail with reference to the drawing. It shows Fig. 1 schematically the structure of a device according to the invention, Fig. 2 the upstream vortex chamber in section parallel to its longitudinal axis, Fig. 3 the injector in section parallel to its longitudinal axis, and Fig. 4 the vortex chamber downstream of the injector in section parallel to its longitudinal axis.

Fig. 1 shows the purely schematic structure of a device 1 according to the invention for the enrichment of a liquid with a gaseous medium, consisting of a pump 5, which pumps the liquid into a first vortex chamber 2 via a supply line. In the vortex chamber 2 downstream injector 3 opens a supply line 6 from an ozone generator or an ozone reservoir 7. The negative pressure generated in the injector 3 provides for the suction or introduction of the gas into the liquid. In the second vortex chamber 4 connected downstream of the injector 3, the best possible mixing of gas and liquid is achieved by generating turbulences. Schematically, the drain line 8 is indicated.

Fig. 2 shows the injector 3 upstream first vortex chamber 2 in detail. The vortex chamber 2 is tubular with an inlet 9 and an outlet 15, preferably with a circular cross-section, but the inner profile of the tube deviates greatly from the cylindrical shape. With z is the longitudinal axis of the vortex chamber and indicated by the arrow the flow direction of the medium.

Essential is a constriction 12 of the inner cross section, which causes extensive turbulence in the liquid flowing through. How out Fig. 2 it can be seen that the inner profile defining the respective cross section along the vortex chamber is undulating. The inner profile in the region of the constriction 12 is also similar to a hill and is not dissimilar to a bell curve. The illustrated preferred embodiment of the vortex chamber 2 shows a wave-shaped profile consisting of two wave crests 10, 12. The respective counterpart in the upper half of the section is symmetrical training a mirrored about the longitudinal axis representation of the wave crest. Between the two wave crests 10, 12 a wave trough 11 is provided with a local maximum in the pipe cross section, wherein the cross section at this bulge is preferably smaller than the inlet cross section of the swirl chamber, preferably between 55% and 80%, in the illustrated embodiment about 65% of the input cross section ,

10b, 12a and 12b show the turning points of the curve. Furthermore, this expression is retained even though it is actually annular (turning) lines indicating the transition from positive to negative curvature of the interior lining surface A. The wave crests need not be symmetrical with respect to their flanks. Thus, the slopes in the turning points 10b, 12a, 12b can be different. It is important and this distinguishes the present invention from the prior art that the internal cross-section of the vortex chamber continuously decreases in the region of the wave crest assumes its minimum and then widens again in a continuous manner.

In the restriction 12, the cross section is preferably less than about 25%, more preferably less than 10% of the input cross section. Depending on the design of the remaining regions of the vortex chamber, it may be advantageous that the cross section even accounts for less than 5% of the input cross section, such as about 2.5% in the illustrated embodiment. In particular, the size of the cross-sectional area also depends on the particular medium, since the Vortex formation is strongly influenced by its viscosity. The information relates to the cross-sectional area and not to the radius or diameter.

As can be seen from the illustration, the change in the cross-section along the entire vortex chamber is not abrupt, but continuous. In the region of the inflection points 12a, 12b, the course of the surface A to the longitudinal axis z has an inclination of preferably between 35 ° and 55 °, more preferably - as also shown - 45 °.

Seen in the flow direction before the constriction 12 constriction 10 provides a larger compared to the constriction 12 flow area, preferably a 7 times to 13 times as large. This is preferably less than about 50%, more preferably less than about 30%, of the input cross section, about 25% in the preferred embodiment. Also, the corrugation forming the constriction 10 is flatter, thus with smaller slopes in its inflection points with respect to the longitudinal axis z, so that the distance of the inflection point 10b from the inlet opening 9 is greater than the distance between the inflection points 12a and 12b. In the region of the point of inflection 10b (no inflection point is formed towards the inlet opening), the slope of the surface A relative to the longitudinal axis z is preferably less than 35 °, preferably approximately 20 °. The initial slope in the entrance area is preferably between 35 and 55 °. In the illustrated embodiment, it is about 45 °

In the preferred embodiment, the constriction 12 is located in the region of the center of the vortex chamber 2, while the constriction 10 directly follows the inlet region and thus, viewed from the inlet 9, lies in the first third of the vortex chamber.

In the immediate vicinity of the constrictions, the inner profile of the vortex chamber can be approximately described by a radius of curvature r10, r11, r12, as in FIG Fig. 2 indicated. The radius of curvature r10 of the first wave crest 10 and that of the first protrusion are more than twice as large as the radius of curvature r12 of the wave crest 12.

The inner surface A of the vortex chamber 2, so that curved surface in the 3-dimesional, which limits the inner profile or the vortex chamber lining, has no discontinuities, cracks, kinks and edges and is therefore in the mathematical sense, a continuously differentiable Function. Of course, small grooves or nubs may be provided in the profile, for example for inducing the smallest vortex, but this does not change the global profile of the wave profile.

The above described inventive configuration of a constriction minimizing the cross section of the vortex chamber results in the desired turbulences mentioned above without substantially slowing down the medium flow, thereby minimizing the pressure differential between the area before the constriction and the area behind the constriction.

In the flow direction subsequent to the constriction 12 is followed by a widening region, which merges into a region 14 with a substantially constant cross section of preferably between 35% and 55%, shown about 45% of the input cross section, to the outlet 15 again an extension 14 in cross section he follows.

Depending on the viscosity, the inflowing medium in the entrance area 9 is reduced in its speed by about 7% and accumulated in the area of the first constriction 10. The subsequent cross-sectional widening in the area of the bulge 12 dilates the media molecules or the molecular complex and expands interspaces between molecules and molecular complexes. The speed of the media flow falls substantially proportional to the cross-sectional enlargement. Due to the change in cross section between the two constrictions 10 and 12, strong swirls are produced. As already mentioned, these cause a loosening of the molecular complex, in particular between solids and solutes. In part, a mechanical separation of substances is also observed. In the area before and at the bulge there is an increased wall friction and small vortices, which arise in the area of constriction 12 or already before. Due to the particle concentration contained in the medium, which varies greatly in space as a result of the turbulence, as a result of weight shifts in the media flow, a rotation of the medium can be caused about the flow axis, as could be shown in experiments. As a result of the swirl and the expansion occurring in the area after the constriction 12, the media structure is changed in such a way that a mechanical separation of the substances to be oxidized of up to 60% can be achieved in the area with a constant cross section and the subsequent expansion. In the area between constriction 12 and outlet 15 at the same time a feedback of the Vortex at the wall areas of the vortex chamber, which promote the mechanical separation to a not insignificant contribution.

The medium thus prepared provides the best conditions for an optimal partial pressure in the subsequent injector.

The speed of the media flow from the inlet 9 to the outlet 15 of the vortex chamber depends on the inlet cross section, the viscosity of the medium, the flow pressure generated on the input side and the required gas quantity (thus also on the negative pressure in the injector). The exact dimensioning of the vortex chamber depends i.a. also from the quantities contained in the so-called Reynolds number Re, namely the density p, the flow velocity v, the toughness η and the pipe diameter L (Re = ρLv / η). In the case of pipe flows, the transition from laminar to turbulent takes place at a Reynolds number of about 2300, but in the present case, the overall construction must always be taken into account in order to arrive at a preferred embodiment of the invention.

In the following, a preferred embodiment of the injector with reference to the Fig. 3 explained in more detail. The cross section in the input region 16 of the injector 3 is substantially equalized to the outlet cross section of the first vortex chamber 2. The medium is conveyed to the nozzle 18 at the predetermined pressure via a preferably conically narrowing channel 17. The size of the nozzle 18 depends on the one hand on the pressure or the speed of the liquid and on the other hand on the vacuum to be achieved in the immediate region of the nozzle opening. The gas to be provided with the medium is the basis for the dimensioning of the nozzle cross-section. The nozzle is preferably movable in the horizontal direction, for example by screwing. Depending on the medium viscosity, the cross-section must be optimized, since the exit velocity from the nozzle is decisive for the size of the resulting vacuum. In order to achieve an optimum partial pressure of the gas / liquid transition phase, a vacuum of about -0.4 to -0.6 bar should be achieved. The screw-in depth of the nozzle in relation to the point 19, which is defined as the edge to the gas supply 6, is also responsible for the size of the vacuum. Here, an adaptation to the respective medium can take place. Via the gas supply 6, the ozone-air mixture is sucked in and connected in the sequence with the medium. Immediately after, the oxidation begins.

Following the nozzle, an extension is again made in region 20, e.g. conical, the injector cross section, followed by a region 21 of constant cross section. The injector outlet is designated 22.

Fig. 4 shows a preferred embodiment of the injector in the flow direction subsequent second vortex chamber 4. In a similar manner as the first vortex chamber 2, and the vortex chamber 4 is equipped with an inner profile which defines at least one local cross-sectional constriction and has rounded shapes.

At the transition from the injector 3 to the swirl chamber 4 an abrupt cross-sectional restriction is provided, whereby an enormous stagnation vortex arises, which leads to a huge effective route shortening.

Like the vortex chamber 2, the inner profile of the vortex chamber also shows waviness in the section parallel to the tube axis. The preferred embodiment comprises three wave crests 25, 27, 30 and three wave troughs 24, 26, 29 in the wave-shaped profile Fig. 4 As can be seen, the longitudinal axis z of the inner profile is inclined slightly upwards to the horizontal, as a result of which the mixture moves slightly upward against the force of gravity. The inhomogeneities caused by the lowering of particles can be counteracted by this measure, since these are swirled again at the corrugated profile immediately. How out Fig. 4 the wave crests become increasingly asymmetrical with respect to their flanks in the flow direction, ie in other words that the slopes in the two turning points of the wave crest differ. The pitch of those turning points 25a, 27a, 30a located on the side of the peaks 25, 27, 30 facing the inlet increases in the direction of flow, while the pitch in the turning points 25b, 27b, 30b of those flanks leading to the outlet turn away, lose weight. The former may include an almost vertical angle with the tube axis.

As a result of this configuration of the vortex chamber, in particular the different design of the wave crests, vortices of various sizes are induced. The rounded contours of the inner profile together with the fact that there is a continuous flow area in the area around the tube axis along the entire vortex chamber, so you could see through the tube with the eye, has a very beneficial effect on the pressure drop between the inlet and outlet because the medium is not stopped or substantially braked, as is the case in the prior art by baffles with an abrupt cross-sectional constriction, but is excited over the edge only to a comprehensive vortex formation.

In the section normal to the longitudinal axis of the tubular vortex chamber, the cross section is preferably circular, but deviations thereof also fall under the inventive principle, for example elliptical or with rounded in the corner areas polygonal cross sections. Of course, slight deviations from an axisymmetric inner contour of the vortex chamber can occur. In section parallel to the longitudinal axis lay in this case, two wave crests not exactly one above the other, but slightly offset from each other. Also conceivable would be an inner profile, according to which the wave crests continue at least in a partial area helically along the vortex chamber. By such deviations from the circular symmetry, the medium can additionally be given a targeted twist.

Furthermore, it is off Fig. 4 it can be seen that the radii of curvature defining the shape of a wave crest in the region of its immediate maximum, decreasing in the direction towards the outlet 15, thus change from flat wave crests to more curved wave crests. This gives the inner profile to the outlet 15 towards a sharper contour, but this still retains rounded shape. The same happens with the radii of curvature of the troughs. While the shallower contours cause large-scale vortices, smaller vertebrae can be maintained or activated with the more curved structures.

In the following, the preferred embodiment will be described in more detail quantitatively, unless already stated above.

The inlet region 23 of the vortex chamber 4 has a smaller cross section than the outlet 22 of the injector 3. This is followed by a widening in cross section up to a local maximum 24 in the flow cross section followed by a local constriction 25. Overall, this vortex chamber has three local constrictions 25, 27 and 30, between each of which three extensions or bulges 24, 26 and 29 with locally seen maximum cross-section. The corresponding inflection points in the curvature, that is to say where the second derivative of the surface course becomes zero, are respectively designated 25a, 25b, 27a, 27b, and 30a, 30b.

The cross sections in the constrictions 25, 27 and 30 are approximately the same and are preferably about 20% to 40%, more preferably about 30% of the maximum cross section in one of the bulges. The cross sections in the bulges are also about the same size. The inlet cross section is preferably about 15% to 30% of the maximum pipe cross section.

Between the middle constriction 27 and the following bulge 29, a region 28 is provided with a substantially constant cross-section. From the outlet-side constriction 30 to the outlet 31, the cross-section widens slightly again. The inner profile of the vortex chamber tube 4 is also rounded and in mathematical sense, the inner surface A is a continuously differentiable function.

Instead of the region 28 with a substantially constant cross section, for example, a weak or flat trained maximum could be provided. The feature according to the invention that namely in the direction of the outlet opening 15, 31 towards the inclinations to the longitudinal axis z in the turning points 12a, 25a, 27a, 30a to the inlet opening 9, 23 facing flanks of at least two wave crests 10, 12, 25, 27, 30th grow larger, does not exclude such training. It is not necessary for all wave crests to satisfy this condition, but at least two, which need not be immediately adjacent - it could e.g. just a weak maximum between them.

Initial slope in the entrance area is - seen in each case to the pipe axis z - about 35 °. Gradients in the inflection point 25a preferably between 25 ° and 45 °, more preferably about 36 °; in the inflection point 25b, preferably between 30 ° and 50 °, particularly preferably about 40 °; at the point of inflection 27a, preferably between 55 ° and 70 °, more preferably about 65 °; at the point of inflection 27b preferably between 10 ° and 20 °, more preferably about 15 °; at the point of inflection 28b, preferably between 15 ° and 35 °, more preferably about 27 °; at the point of inflection 30a, preferably between 80 ° and 90 °, more preferably about 90 °; at the point of inflection 30b, preferably between 5 ° and 20 °, more preferably about 11 °

After the short-length pre-oxidation in the injector 3 between the region 20 and the outlet 22, which results in a pressure relief of the medium (necessary partial pressure ranges), is fed via the adapted outlet cross-section 22 which is in oxidation medium of the vortex chamber. The vortex chamber has the task of reducing the oxidation distance in order to reduce the technical design of the plant. At the transition injector 3 and at the entrance vortex chamber 4, there is a sudden cross-sectional restriction, with an enormous stagnation arises, which leads to a significant design shortening with appropriate design.

In the region between inlet 23 and first constriction 25, the gas-laden medium experiences a re-whirling, so that there is another shortened oxidation time frame. Over the distance between the first constriction 25 and the vortex chamber outlet, the medium is accelerated, further vortexed and swirled back again.
Shaping over this area provides a 50% increase in gas transfer to the medium over the prior art. The walls of the vortex chamber provide a flow-favoring oxidation of the media due to the listed shaping.

The invention is not limited to the embodiment shown. It has been found that even a single constriction in the respective vortex chamber with the design according to the invention as a wave crest is sufficient to substantially increase the efficiency of such a device with regard to oxygen enrichment. In addition, much smaller input-side pumping power is required. Namely, by the continuous cross-sectional constriction or expansion, the entire medium is hardly hindered in its flow through the vortex chamber, although long-range turbulence of any magnitude can be induced. With the number of constrictions and the special design of the respective inflection points, the efficiency of the device according to the invention can be further optimized, but these represent preferred embodiments.

Claims (33)

1. An eddy chamber for generating turbulence in the medium flowing through it, with an inlet and an outlet, and with at least two constrictions in its cross section, where, in cross section parallel to its longitudinal axis, the internal profile of the eddy chamber has the form of wave crests (10, 12, 25, 27, 30) in the area of the constrictions, characterized in that the angles to the longitudinal axis (z) at the inflection points (12a, 25a, 27a, 30a) on the inlet (9, 23)-facing flanks of at least two wave crests (10, 12, 25, 27, 30) become larger in the direction toward the outlet (15, 31).
2. An eddy chamber according to claim 1, characterized in that the angles to the longitudinal axis (z) at the inflection points (10b, 12b, 25b, 27b, 30b) on the outlet (15, 31)-facing flanks of at least two wave crests (10, 12, 25, 27, 30) become smaller in the direction toward the outlet (15, 31).
3. An eddy chamber according to any of claims 1 or 2, characterized in that the internal profile (A) is essentially circular and symmetric to the longitudinal axis (z).
4. An eddy chamber according to any of claims 1 to 3, characterized in that the entire internal profile (A) is wavy along the longitudinal axis (z).
5. An eddy chamber according to any of claims 1 to 4, characterized in that, for at least one wave crest (12, 25), the angles at its inflection points (12a, 12b, 25a, 25b) to the longitudinal axis (z) are between 25° and 55°.
6. An eddy chamber according to any of claims 1 to 5, characterized in that the cross section in the area of at least one wave crest (10, 12, 25, 27, 30) is less than 40% of the maximum cross section of the eddy chamber.
7. An eddy chamber according to any of claims 1 to 6, characterized in that two wave crests (10, 12) are provided.
8. An eddy chamber according to claim 7, characterized in that a wave trough (11) with a local maximum in its cross section is provided between the two wave crests (10, 12), where the cross section at this outward bulge is preferably smaller than the inlet cross section of the eddy chamber (2), preferably between 55% and 80% of the inlet cross section.
9. An eddy chamber according to any of claims 7 to 8, characterized in that the cross section of the wave crest (12) downstream from the wave crest (10) is less than 25%, preferably less than 10%, particularly preferably less than 5%, of the inlet cross section.
10. An eddy chamber according to any of claims 7 to 9, characterized in that the angle at the inflection points (12a, 12b) of the wave crest (12) to the longitudinal axis (z) is between 35° and 55°, and preferably 45°.
11. An eddy chamber according to any of claims 7 to 10, characterized in that the cross section of the wave crest (10) upstream of the wave crest (12) is less than 50%, preferably less than 30%, of the inlet cross section.
12. An eddy chamber according to any of claims 1 to 6, characterized in that three wave crests (25, 27, 30) are provided.
13. An eddy chamber according to claim 12, characterized in that the cross sections at the wave crests (25, 27, 30) are approximately of the same size and about 20% to 40%, preferably about 30%, of the maximum cross section in one of the outward bulges (24, 26, 29) situated between the constrictions, where the cross sections in the outward bulges (24, 26, 29) are approximately of the same size.
14. An eddy chamber according to any of claims 12 to 13, characterized in that the inlet cross section of the eddy chamber (4) is about 15% to 30% of the maximum tube cross section.
15. An eddy chamber according to any of claims 12 to 14, characterized in that the slopes at the inflection point (25a) are between 25° and 45°, preferably about 36°, at inflection point (25b) between 30° and 50°, preferably about 40°, at inflection point (27a) between 55° and 70°, preferably about 65°, at inflection point (27b) between 10° and 20°, preferably about 15°, at inflection point (28b) between 15° and 35°, preferably about 27°, at inflection point (30a) between 80° and 90°, preferably about 90°, and at inflection point (30b) between 5° and 20°, preferably about 11°, with respect to the longitudinal axis (z).
16. An eddy chamber according to any of claims 12 to 15, characterized in that an area (28) of essentially constant cross section is provided between the middle wave crest (27) and the downstream outward bulge (29).
17. A device for increasing the concentration of a gaseous medium in a liquid medium, especially for supplying oxygen for water treatment, comprising an injector (3) for the gas feed, an eddy chamber (2) upstream of the injector (3), the chamber comprising at least one constriction in its cross section, and an eddy chamber (4) downstream of the injector (3), the chamber comprising at least one constriction in its cross section, where, in cross section parallel to its longitudinal axis (z), the internal profile (A) of the downstream eddy chamber (4) has the form of a wave crest (25, 27, 30) in the area of the constriction, characterized in that in cross section parallel to its longitudinal axis (z), the internal profile (A) of the upstream eddy chamber (2) has the form of a wave crest (10, 12) in the area of the constriction, and in that at least two wave crests (10, 12, 25, 27, 30) are provided in at least one eddy chamber (2, 4), where, in the direction toward the outlet (15, 31) of the eddy chamber (2, 4), the angles to the longitudinal axis (z) at the inflection points (12a, 25a, 27a, 30a) on the inlet (9, 23)-facing flanks of at least two wave crests (10, 12, 25, 27, 30) become larger.
18. A device according to claim 17, characterized in that, in the direction toward the outlet (15, 31), the angles to the longitudinal axis (z) at the inflection points (10b, 12b, 25b, 27b, 30b) on the outlet (15, 31)-facing flanks of at least two wave crests (10, 12, 25, 27, 30) become smaller.
19. A device according to any of claims 17 to 18, characterized in that the internal profile (A) of at least one eddy chamber (2, 4) is essentially circular and symmetric to its longitudinal axis (z).
20. A device according to claim 17 to 19, characterized in that the entire internal profile (A) of at least one eddy chamber (2, 4) is wavy along its longitudinal axis (z).
21. A device according to any of claims 17 to 20, characterized in that the longitudinal axis (z) of the eddy chamber (4) downstream from the injector (3) is tilted slightly upward toward the outlet (31).
22. A device according to any of claims 17 to 21, characterized in that, at least in the case of one wave crest (12, 25) in at least one eddy chamber (2, 4), the angles at its inflection points (12a, 12b, 25a, 25b) to the longitudinal axis (z) are between 25° and 55°.
23. A device according to any of claims 17 to 22, characterized in that, in at least one eddy chamber (2, 4), the cross section in the area of at least one wave crest (10, 12, 25, 27, 30) is less than 40% of the maximum cross section of the eddy chamber.
24. A device according to any of claims 17 to 23, characterized in that two wave crests (10, 12) are provided in the upstream eddy chamber (2).
25. A device according to claim 24, characterized in that a wave trough (11) with a local maximum in its cross section is provided between the two wave crests (10, 12) of the upstream eddy chamber (2), where the cross section at this outward bulge is preferably smaller than the inlet cross section of the upstream eddy chamber (2), preferably between 55% and 80% of the inlet cross section.
26. A device according to any of claims 24 to 25, characterized in that, in the case of the upstream eddy chamber (2), the cross section of the wave crest (12) downstream from the wave crest (10) is less than 25%, preferably less than 10%, particularly preferably less than 5%, of the inlet cross section.
27. A device according to any of claims 24 to 26, characterized in that the angle at the inflection points (12a, 12b) of the wave crest (12) to the longitudinal axis (z) is between 35° and 55°, and preferably 45°.
28. A device according to any of claims 24 to 27, characterized in that the cross section of the wave crest (10) upstream of the wave crest (12) is less than 50%, preferably less than 30%, of the inlet cross section.
29. A device according to any of claims 17 to 28, characterized in that three wave crests (25, 27, 30) are provided in the downstream eddy chamber (4).
30. A device according to claim 29, characterized in that the cross sections at the wave crests (25, 27, 30) of the downstream eddy chamber (4) are approximately of the same size and about 20% to 40%, preferably about 30%, of the maximum cross section at one of the outward bulges (24, 26, 29) situated between the constrictions, where the cross sections in the outward bulges (24, 26, 29) are approximately of the same size.
31. A device according to any of claims 29 to 30, characterized in that the inlet cross section of the downstream eddy chamber (4) is about 15% to 30% of the maximum tube cross section.
32. A device according to any of claims 29 to 31, characterized in that, in the downstream eddy chamber (4), the slopes at the inflection point (25a) are between 25° and 45°, preferably about 36°, at inflection point (25b) between 30° and 50°, preferably about 40°, at inflection point (27a) between 55° and 70°, preferably about 65°, at inflection point (27b) between 10° and 20°, preferably about 15°, at inflection point (28b) between 15° and 35°, preferably about 27°, at inflection point (30a) between 80° and 90°, preferably about 90°, and at inflection point (30b) between 5° and 20°, preferably about 11°, with respect to the longitudinal axis (z).
33. A device according to any of claims 29 to 32, characterized in that an area (28) of essentially constant cross section is provided between the middle wave crest (27) of the downstream eddy chamber (4) and the downstream outward bulge (29).

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