DE202022106532U1 - Mixing device and use - Google Patents

Abstract

Mixing device (7) working according to the principle of a mammoth pump for circulating a fluid (W) in a fluid container (S) filled with the fluid from a first level (H9) to a second level (H10) with a longitudinal axis (X). extending, waveguide-like base body forming a flow channel (15) with a lateral surface (M), comprising an inlet (9) located at a lower end for sucking in the fluid and an outlet (10) located at an upper end for dispensing the fluid (W) and a gas outlet (5S) located therebetween for blowing in a gas to generate suction at the inlet (9), the inlet (9) being arranged in a funnel-shaped inlet area (7B), the outlet (10) being arranged in a tubular section (7A) is arranged, and the funnel-shaped inlet area (7B) and the tubular section (7A) form the flow channel (15), characterized in that the base body is formed in two parts is such that the inlet area (7B) and the tubular section (7A) each form an independent component which are connected to one another to form the base body.

Description

The invention relates to a mixing device in the manner of a mammoth pump and use of the same in a water treatment device.

Mammoth pumps are mostly vertical, i.e. in the direction of gravity, set up devices with an inlet located at a first, lower end, an outlet located at the opposite, upper end and a flow channel extending therebetween for conveying liquids from the inlet to the outlet. The liquid is conveyed by gases introduced into the flow channel, which locally reduce the specific density of the liquid at the point of introduction, rise in the flow channel and thereby develop a negative pressure, via which further liquid is sucked in from below.

Water treatment devices are used in particular for the treatment of waste water, for obtaining drinking water and for the pre- and/or after-treatment of aqueous solutions. Water treatment devices are to be understood as meaning systems whose main purpose is the treatment of water, i.e. removing unwanted substances from the water and/or enriching or mixing with desired additives, such as precipitants or activated sludge.

Mixing devices that are known from the prior art and that work according to the principle of a mammoth pump are, for example, from the German publication DE 2 943 870 A1 known. The mixing device known from this comprises an inlet which is enlarged in the manner of a plate, an outlet which is directed in the radial direction and a flow channel which extends in between and into which gas is blown via distributor pipes.

Due to the plate-like inlet, the distributor pipes and a dividing wall extending between them, through which a separation of lime and iron sulphate should be possible, the mixing device is at high risk of clogging since, in particular, whirled-up bottom sediments can get stuck in the bottlenecks and can accumulate. Furthermore, the mixing device is space-consuming and therefore expensive to transport.

Against this background, the invention has set itself the task of specifying a mixing device which avoids some disadvantages of the prior art and, in particular, is resource-efficient with regard to manufacturing, installation and operating costs.

The mixing device according to the invention serves the purpose of raising a liquid fluid in a fluid container from a first level to a second level and thereby circulating and mixing the fluid. Since the mixing device according to the invention works according to the principle of a mammoth pump, i.e. a gas is supplied to the mixing device during operation, the fluid can be enriched with this gas. However, if no interaction between the gas and the fluid is desired, the function of the gas can also be reduced entirely to the function of circulation. Depending on the application, gases that are inert to the fluid or its components (especially impurities or admixtures) or gases that are more reactive are suitable. With a suitable placement, in addition to the fluid, other foreign matter, such as sediments, can of course also be sucked in and mixed with the fluid.

The mixing device is constructed in such a way that it comprises a waveguide-like base body which extends along a longitudinal axis and has an upper end and a lower end, an inlet being arranged at the lower end and an outlet being arranged at the upper end. The waveguide-like base body, more precisely its wall, forms a flow channel between the inlet and the outlet. The inlet has an inlet opening through which fluid can be sucked in at the lower end, while the outlet has an outlet opening through which the fluid sucked in at the inlet and conveyed through the flow channel is discharged. A gas outlet for blowing in (supplying) a gas is located between the inlet and the outlet. The gas is blown in under pressure which is at least as high or higher than the hydrostatic pressure generated by the fluid column above the gas outlet. Otherwise a gas supply would not be possible. As the injected gas rises up in the flow channel, it creates a (after)suction effect at the inlet, so that the fluid is sucked in at the inlet.

In order to increase the suction area at the inlet, the inlet is enlarged like a funnel, so that the inlet with the inlet opening is located at the lower end of a funnel-shaped section (hereinafter referred to as the inlet area). The funnel-shaped inlet area then merges into a tubular section further up. The funnel-shaped inlet area forms a lower section of the flow channel. The tubular section forms an upper section of the flow channel.

The mixing device is characterized in that the main body is essentially made in two parts from the funnel-shaped inlet area and the tubular section, with the funnel-shaped inlet area and the tubular section each being independent components which are connected to one another to form the main body of the mixing device are.

This connection is preferably detachable.

The detachable connection can be, for example, as a direct connection - for example as a plug-in connection (e.g. by joining both components slightly undersized/press fit), as a snap connection (e.g. by elastically deflectable snap elements extending into the opening of the joining partner) or as a screw connection (e.g. with a circumferential thread and mating thread at the lower end of the tubular section or at the upper end of the funnel-shaped inlet area) or as an indirect connection - i.e. with the aid of connecting elements such as pins or screws.

Non-releasable connections are also possible, for example by using adhesives or adhesion promoters with the same effect, welded connections and the like.

Due to a two-part design, the components of the mixing device can be manufactured independently of one another, they can be transported independently of one another and can be assembled and installed on site and with little effort to form a ready-to-use mixing device.

Add-on and fastening parts, such as fastening anchors, bracing wires or feed parts for the gas supply and other aids are not to be considered as parts in the sense of the term "two-piece".

In a further improved embodiment, the tubular section can be designed in the shape of a cone, i.e. with a cone section with an obliquely tapering lateral surface. This allows tubular sections to be stacked one inside the other in a space-saving manner. Conical is not to be understood strictly mathematically, but functionally, so that other non-conical sections in the mathematical sense, e.g. pyramid-shaped sections, which can be stacked due to this shape, should also fall under the term “conical” within the meaning of the invention.

The conical, tubular section, i.e. its wall, preferably has an inclination of between 1:0.005 and 1:0.05 with respect to the vertical. The opening angle of the conical section is therefore in the order of less than 5°.

The funnel-shaped inlet area can advantageously be rounded, i.e. without edges, for example with a hyperbolic or parabolic contour. As a result, flow losses during suction can be minimized. The inlet area is particularly preferably inclined at its lower end at an angle of at most 45° or less with respect to the vertical. This ensures a good compromise between vertical and horizontal suction effect, so that the mixing device unfolds a large effective area (covering the ground) and at the same time ensures good mixing of the fluid sucked in and any foreign matter sucked in, in particular sediments. At the same time, this also reduces the risk of the flow channel becoming clogged.

The inlet and the outlet are expediently matched to one another in such a way that the inlet opening has an opening cross section that is twice as large as the opening cross section of the outlet. In other words, it is advantageous if the inlet opening has at least four times the area of the outlet. As a result, changes in the flow velocity that occur as a result of the narrowing of the cross section from the inlet to the outlet can be advantageously limited.

It can also be advantageous in terms of flow technology if at least the tubular section of the mixing device is designed without interruption, i.e. that the tubular section (apart from the gas outlet) forms a closed lateral surface and fluid only flows into and out of the mixing device via the inlet opening and the outlet opening can be promoted. Optionally, the funnel-shaped inlet area can also be designed without interruption.

Mixing effects can be further improved if a fluid guide device is provided in the mixing device, which additionally rotates the flow field directed from bottom to top or a part thereof. A suitable fluid guide device is, for example, helix-like inserts, spirals or guide vanes that are inclined relative to the longitudinal axis and extend in sections from bottom to top.

In a particularly expedient embodiment of a fluid guide device, it extends at least partially below the gas outlet in the direction of the inlet. This causes - by analogy a cyclone or the outflow flow in a bathtub - a downward flow spiral is created which propagates down past the inlet, resulting in a spiral suction at the bottom of the fluid container.

In order to keep the fluid guide device structurally simple and thus inexpensive to produce, the fluid guide device can only partially cover the flow channel in cross section, in particular in such a way that it extends outside along the lateral surface of the base body, but does not completely cover the flow channel when viewed in cross section, so that a central part of the flow channel remains open, through which the fluid and gas introduced via the gas outlet can flow directly from the inlet to the outlet. This makes it possible to dispense with structurally complex designs, in particular continuous Archimedean screws, without having to forego the advantage of a spiral suction in the inlet area and below it.

For this purpose, the fluid guide device is preferably designed in several parts as a multiplicity of guide vanes, each of which winds up helically in sections along the outer surface of the base body of the mixing device.

The fluid guide device or its parts are advantageously detachably attached to or on the waveguide-like base body of the mixing device, for example screwed on.

As components that are designed separately and only added later, these do not impede the stackability of tubular sections in particular if they are designed conically.

In order to reduce the maintenance intensity, the gas outlet of the mixing device is advantageously arranged in such a way that it opens directly into the lateral surface of the tubular section and ends practically flush with the lateral surface without protruding significantly into the flow channel. In this way, it is avoided that solids or sediment fractions transported along with the fluid can get caught at the gas outlet or grow on it. As a result, cleaning intervals for the mixing device can be reduced, if not eliminated entirely. A flush closure within the meaning of the invention is given in particular when the gas outlet is no more than 15%, preferably less than 10%, more preferably no more than 5% and particularly preferably no more than 2% of the diameter of the mixing device at the height of the gas outlet protrudes into the flow channel.

The gas outlet of the mixing device is preferably exactly one gas outlet with a preferably circular contour. In addition, the gas outlet can be grilled in order to reliably prevent foreign substances from penetrating into the gas supply, but has no other air distribution devices.

For an optimal suction effect, the gas outlet is arranged at a suitable height in the mixing device, in particular at a height that - based on the overall length of the mixing device - is in the lower half, preferably the lower third, of the mixing device and, for example, a distance between Has 20 and 150cm to the inlet.

It is preferred if the mixing device has a length of between 1.5 and 4 m. As a result, the mixing device can be used expediently in common fluid containers (basins) with heights between 2 and 6 m. It is also preferred if the overall length of the mixing device is at least four times the opening cross section of the outlet.

Parts of the mixing device can be made of a metal, a plastic or a ceramic. However, it is preferred if at least the inlet area is made of a plastic, in particular a duromer or thermoplastic. This allows a high degree of freedom of design in terms of shape with low production costs, light weight and a long service life even in adverse environmental conditions. For analogous reasons, the tubular section can also be made of a plastic. The plastic is preferably fiber-reinforced.

From another aspect, the invention also relates to the use of the mixing device described above in a water treatment device, i.e. the installation of the mixing device in a water-filled fluid container or basin for treating the water, especially for treating waste water or for treating drinking water.

By using it in a water treatment device, it is possible to mix introduced gases evenly and as homogeneously as possible with the water and to distribute them in the water tank, for example in order to initiate or accelerate desired subsequent processes. The mixing device can replace mechanical agitators which are otherwise customary for this purpose and/or a large number of gas outlets distributed over the water tank. This saves known disadvantages of these alternatives. For example, mechanical agitators are expensive, error-prone and not suitable for every water tank geometry. A large number of gas outlets is material-intensive due to the many additional lines required. Both alternatives are also maintenance and cleaning-intensive.

In an expedient variant, the mixing device can be used in a water treatment device which comprises two or more fluid containers, each of which is intended to be charged with a gas.

As already indicated above, a process step that is often used in water treatment devices is the controlled introduction of gases into the water to be treated to initiate and accelerate a chemical, biological or chemobiological and/or physical process, for example the introduction of atmospheric oxygen to oxidize substances contained in the water ingredients or the removal of dissolved, supersaturated gases such as CO ₂ or CH ₄ . In this context, it is known, inter alia, to introduce pressurized oxygen into water tanks in a controlled manner via rod aerators, ie lances.

Such a water treatment device and an associated sequence-batch-reactor method is shown in the US patent application U.S. 4,663,044 A. The U.S. 4,663,044 A shows in particular the blowing of atmospheric oxygen into different (waste) water tanks A, B, C via an air distribution system mounted close to the ground with a number of outlets 114, 122, 132, which are supplied with compressed air via an air supply device 112, the (waste) water tanks with are filled with water that is in different treatment phases.

A disadvantage of such water treatment devices with multiple fluid containers is that the compressed air fed into the individual containers cannot be regulated, although this would be fundamentally desirable due to the different treatment phases of the waste water. However, a corresponding control device with controllable control valves in the supply line or lines would be associated with high costs.

Against this background, the use of the mixing device according to the invention in the water treatment device described in more detail below has proven to be surprisingly expedient, since on the one hand rapid, uniform and as complete as possible mixing of gases introduced into the water is possible and on the other hand the gas can be introduced with comparatively little energy consumption . The gas injection under pressure is one of the main energy cost drivers in a water treatment device. Finally, it is also possible to control the introduction of gas into different water tanks, but to accomplish this without any control effort.

The water treatment device for water treatment, in particular for the biological treatment and treatment of waste water using activated sludge, comprises in detail at least two fluid containers which are fluidically connected to one another, namely a first fluid container (selector) and a second fluid container (reactor), between which continuous or discontinuous (batch wise) water can be exchanged and transferred. The water exchange takes place via an overflow edge arranged between the fluid containers, so that water overflows from the selector into the reactor from a predetermined filling level in the selector. The flow of water is therefore essentially unidirectional from the selector into the reactor, with the reactor being fed with water to be treated and the treated water being drawn off from the reactor. The overflow edge is formed by an upper side of a dividing wall separating the first and second fluid containers.

The first and the second fluid container have a corresponding first or second gas supply with one or more first or second gas outlets, e.g Standing gas (compressed gas) are supplied and through which the compressed gas is entered into the fluid container. The gas outlets are arranged at a specific vertical height relative to the respective fluid container bottoms.

The compressed gas can be compressed air, ie atmospherically obtained and compressed ambient air. However, it can also be a different gas, especially an industrial gas such as CO ₂ , O ₂ or N ₂ obtained by process engineering.

The water treatment device is characterized in that the first fluid container, the selector, includes the mixing device according to the invention. The mixing direction is arranged vertically, i.e. upright, in the first fluid container, so that the flow channel of the mixing device extends essentially vertically and the flow passes through it in a flow direction from bottom to top.

The water treatment device is further characterized in that the vertical distance between the gas supply of the selector and its bottom is greater than the vertical distance from the gas outlet of the gas supply of the reactor to its bottom, so that with the same level of reactor and selector, the hydrostatic pressure at the gas outlet of the selector is lower than the hydrostatic pressure at the gas outlet of the reactor. This ensures that gas is fed into the selector for any fill level of the selector that is greater than or equal to the fill level of the reactor. In this context, fill level is to be understood as being independent of volume in the sense of a fill height or level of the fluid container, but not in the sense of a filling volume.

In other words, it is only important that there is always a smaller water column above the gas outlet of the mixing device in the selector, or at most the same height as above the gas outlet of the reactor - i.e. a lower hydrostatic pressure is acting - so that with every filling level ratio of the selector a (minimum) gas feed into the selector is guaranteed for the reactor.

This arrangement has the advantage, among other things, that the water in the fluid containers, which can be in different treatment stages, can be treated with different amounts of gas from the same gas source, without having to distribute and adjust the amount of gas or the gas amount ratios from the first or second gas outlet flow or should flow, a pressure reduction (valves, shut-off flaps) is required. As a result, the total demand for compressed air can be reduced and thus energy costs can be saved.

In an expedient variant, the water treatment device can be operated in different phases, namely a charging phase (filling phase), a gas supply phase, a sedimentation phase and a discharge phase (decanting phase). The individual phases can be carried out one after the other. However, the feed phase can also be carried out simultaneously with or at least partially overlapping with the gas feed phase. The loading phase can also partially or completely overlap with all other phases.

In the charging phase, the first fluid container is charged, i.e. filled, with water to be treated. The water, which may have already been partially or completely pretreated in the first fluid container, then overflows into the second fluid container via the overflow edge. In the gas supply phase, gas, in particular compressed ambient air, is supplied to the water in the first and second fluid containers via the gas outlets. The gas supply can overlap completely or at least partially with the charging phase. Furthermore, the positioning of the first gas outlet, which opens into the mixing device, ensures suction into the mixing device, so that water close to the inlet in the first fluid container is sucked in via the inlet opening, mixed with the introduced gas and returned to the first fluid container via the outlet opening of the mixing device is fed back. In this way, in addition to good mixing of the water with the gas, good mixing of different water layers and possibly also of water with any sediments lying on the bottom of the fluid container, such as biomass or activated sludge, is achieved. In the sedimentation phase, the air supply and, if necessary, the ongoing supply of water is interrupted, so that particle agglomerations in the water that are heavier than water can sink to the bottom (sediment) in the first or second fluid container and there over time form a growing and thicker (higher) sediment layer. In the withdrawal phase, water that is essentially free of particle agglomeration or at least with little particle agglomeration is finally withdrawn (decanted) from the highest water layers, i.e. from the layers furthest away from the sedimentation layer, via a withdrawal device from the second fluid container. During the withdrawal phase, the level in the second container drops. The sum of these four phases (feed, gas supply, sedimentation, discharge) forms a cycle. The water drawn off forms the end product and can be subjected to further post-treatment steps.

In a specific embodiment, the water treatment device can be a waste water treatment device for treating waste water, for example domestic or also industrial waste water, in which the waste water to be treated is to be cleaned of pollutants and impurities. Typically, after mechanical pre-treatment stages, in which at least coarse contaminants and dirt particles (floating debris, foreign bodies, sand and debris, etc.) are filtered out via rakes and sand traps, the wastewater enters the first fluid container in the charging phase, with the level constantly rising during the first filling until the level reaches the overflow edge between the first and the second fluid container and then, ie when the height of the overflow edge is exceeded, overflows into the second fluid container. The feeding (filling) of the waste water into the first fluid container can be done continuously or intermittently, so that the feeding of the waste water from the first to the second fluid container holder over the overflow edge takes place continuously or intermittently.

During the aeration phase, compressed air, i.e. pressurized ambient air, is applied to the waste water via the gas outlets in both the first and second fluid containers. This can accelerate oxidation processes, in particular the conversion of carbon compounds into carbon dioxide and water or the conversion of ammonium into nitrate (nitrification). The oxidation processes can be supported by microorganisms that accumulate in the fluid containers, metabolize impurities and bind them in particle agglomerations. These particle agglomerations, consisting of impurities, metabolic products and microorganisms, form so-called activated sludge, which sinks to the bottom, especially in the subsequent sedimentation phase, and forms the constantly growing sedimentation layer. As already explained above, the gas supply via the mixing device ensures excellent mixing of different layers of water, especially old water and water that is newly added during charging, the distribution of activated sludge and a homogeneous distribution of the air introduced in the first fluid container. A separate agitator for mixing is not required. A separate gas distribution device such as an active pressure reducer or a pressure control valve is also not required, since - provided that it is a known process with known process parameters - the waste water in the first fluid container has a known gas requirement for the desired with a known, average length of stay Has mixing and / or oxidation processes, which is in an approximately fixed ratio to the gas requirement in the second fluid container, so that the gas to be introduced into the first and the second fluid container is subject to an approximately constant ratio, e.g. a ratio of 30:70. Technically, this desired ratio can be mapped or at least approximated via the different, hydrostatic height of the gas outlets in the first and second fluid container. “Hydrostatic height” is to be understood as the vertical distance between the gas outlets and the level of the fluid tank when both fluid tanks have the same water line. A slight deviation in the introduction of compressed air as a result of the fluctuating filling level in the second fluid container (rising again after the withdrawal phase) does not detract from this, especially since this is limited to the duration of the charging phase.

It can also be advantageous for the water treatment device - and especially for the above-mentioned waste water treatment device - to determine the ratio of the gas supply to the first or second fluid container not only via the hydrostatic height of the gas outlets, but also via the pipe cross-sections of the gas supplies leading to the gas outlets (permanently ) to set. It is expedient, for example, if a maximum pipeline cross-section for the gas supply to the first fluid container (selector) is smaller by a factor of 2, 3 or 5 than a maximum pipeline cross-section for the gas supply to the second fluid container. As a result, a more extensive adjustment of the gas supply quantities is possible, since the setting of gas supply quantities via line cross-sections and via the hydrostatic head are each subject to different physical laws. As a result, a minimum gas supply into the first and the second fluid container can always be ensured, especially in the case of strongly divergent fill levels between the first and second fluid containers. The possibility of varying or adjusting the hydrostatic height of the gas supply by positioning the gas outlet differently remains unaffected. The hydrostatic height of the gas supply is therefore not necessarily fixed, but can be adapted to the circumstances, for example by providing a large number of blind connections located at different heights on the device, of which only one is/is connected to the gas source. The term adjustment used here means the adjustment of the hydrostatic height during installation and/or maintenance of the device, but not during ongoing operation of the device. However, an adaptive adjustment of the hydrostatic height of the gas outlet during operation—for example by means of electric motor, hydraulic or pneumatic drive means—is possible.

In a particularly expedient embodiment of the water treatment device, any active pressure control elements for distributing the gas quantities supplied to the first and the second fluid container can be completely dispensed with. It is assumed that the first and the second gas outlet are supplied from the same gas source, i.e. the gas source has a supply line from which the gas supplies leading to the first or second gas outlet branch off, without throttle valves or other active control elements (such as Volume regulator or pressure regulator) are arranged, which are adjustable during operation of the water treatment device. Shut-off valves, which enable a permanent closure of a gas supply, e.g. for maintenance purposes, are not to be understood as active control elements in the aforementioned sense.

• Die Durchmischungsvorrichtung ist zweckmäßig unterhalb des Flüssigkeitsspiegels angeordnet, befindet sich also ‚unter Wasser‘. Hierdurch können insb. Emissionen und Immissionen von Luft und Lärm reduziert werden. Besonders bevorzugt befindet sich die Durchmischungsvorrichtung wenigstens 100cm unterhalb des Flüssigkeitsspiegels des ersten Fluidbehälters. Hierdurch können insb. mittlere Wasserschichten mit dem Gas sowie vom Boden angesaugten Ablagerungen (Belebtschlamm) durchmischt werden. Dies kann Umsetzungsraten (Oxidationsprozesse) beschleunigen, da oberflächennahe Wasserschichten ohnehin auf natürliche Art und Weise mit der Umgebungsluft in Kontakt stehen und deshalb bereits mit Sauerstoff gesättigt ist, so dass durch eine hinreichend tiefe Positionierung der Durchmischungsvorrichtung unter Wasser die Gesamtmenge an im Wasser verfügbarem Sauerstoff erhöht werden kann.

The mixing device expediently has a specific positioning and specific dimensions:

• The mixing device is expediently arranged below the level of the liquid, ie it is located 'under water'. As a result, emissions and immissions from air and noise in particular can be reduced. The mixing device is particularly preferably located at least 100 cm below the liquid level of the first fluid container. As a result, the middle water layers in particular can be mixed with the gas and deposits (activated sludge) sucked in from the ground. This can accelerate conversion rates (oxidation processes), since layers of water close to the surface are naturally in contact with the ambient air anyway and are therefore already saturated with oxygen, so that the total amount of oxygen available in the water is increased by positioning the mixing device sufficiently deep under water can be.

The mixing device advantageously has an overall length which is between 30% and 80%, preferably between 60% and 70% of the overall height of the first fluid container. A length selected in this way can ensure that all water layers are almost completely mixed, in particular the lower water layers with the water layers further up. The total length is the distance between the (lower) inlet and the (upper) outlet.

It may be preferable to arrange the mixing device close to the bottom, especially in such a way that the inlet opening of the mixing device is close to the bottom of the first fluid container, preferably at a distance of between 5 and 50 cm. A distance selected in this way ensures, on the one hand, a sufficient distance to a layer of sediment deposited on the bottom, so that the inlet is never blocked or clogged by the sediments, and, on the other hand, that the layer of sediment is whirled up during the gas supply phase, sucked in and flown through the flow channel of the mixing device in higher water layers can be transported.

It is advantageous if the gas outlet of the second fluid container is also close to the bottom, here the bottom of the second fluid container. The second gas outlet is expediently arranged near the bottom at a distance of no more than 30 cm from the bottom of the second fluid container. In this case, the second gas outlet is preferably—in contrast to the gas outlet of the first fluid container, which opens into the mixing device—designed as a finely perforated, multiple outlet opening. The finely perforated, multiple outlet opening can be plate-shaped, disk-shaped, bar-shaped or tubular. It can also be divided into a large number of groupings or strands in the form of plates, tubes or bars. It is possible for the gas outlets to be made of finely porous materials, such as perforated plastic or porous, mineral materials, or to include them, which break up the outflowing gas into small gas bubbles.

In an advantageous further development, the bottoms of the first and second fluid containers are arranged essentially at the same geodetic height and are preferably designed to be flat, i.e. level. This reduces the construction costs for a water treatment plant.

Further possible advantageous configurations of the aforementioned mixing device are explained below. The mixing device can be used in an aforementioned water treatment device. However, it is also conceivable to use the mixing device in other fields of application, i.e. independently of a water treatment device. A restriction of the mixing device to use in a water treatment device is therefore not intended; rather, any indications of use only serve as an exemplary explanation of one (of several) possible purposes of use.

The different aspects of the invention are explained below by way of example with reference to the attached figures, with the same or comparable components being provided with the same or comparable reference symbols, so that reference is made alternately to the previous and/or subsequent explanations relating to these reference symbols.

• 1 eine Schemaskizze einer Wasserbehandlungsvorrichtung,
• 2 eine Schemaskizze einer erfindungsgemäßen Durchmischungsvorrichtung,
• 3 eine Schnittansicht (3A), eine Explosionsdarstellung (3B) sowie eine Aufsicht (3C) der erfindungsgemäßen Durchmischungsvorrichtung aus 2,
• 4 eine Schemaskizze in zwei Zuständen (4A und 4B) einer Wasserbehandlungsvorrichtung mit unterschiedlich tiefen Fluidbehältern,
• 5 eine Schemaskizze analog 4 bei Einsatz einer erfindungsgemäßen Durchmischungsvorrichtung, sowie
• 6 eine Schemaskizze analog den 4 und 5 bei Einsatz einer erfindungsgemäßen Durchmischungsvorrichtung.

show it

• 1 a schematic sketch of a water treatment device,
• 2 a schematic sketch of a mixing device according to the invention,
• 3 a sectional view ( 3A ), an exploded view ( 3B ) and a supervisor ( 3C ) of the mixing device according to the invention 2 ,
• 4 a schematic sketch in two states ( 4A and 4B ) a water treatment device with fluid containers of different depths,
• 5 a schematic sketch analogously 4 when using a mixing device according to the invention, and
• 6 a schematic sketch analogous to the 4 and 5 when using a mixing device according to the invention.

For a better understanding of a possible application of the invention in a water treatment device should be based on the 4A and 4B First, some basic problems in water treatment are explained like wood carvings, before esp 2 until 3C the actual invention is discussed. A possible application is explained below using wastewater treatment, but it can also be extended to other areas of application, mutatis mutandis.

The in the 4A and 4B The schematic drawings shown represent three fluid containers connected in series, which are referred to below as selector S, captor K and reactor R. All three fluid containers S, K, R are filled with a fluid, here water W, and each have a gas supply 4K, 4S, 4R reaching vertically into the fluid container with gas outlets 5K, 5R, 5S located at their respective lower end. A gas, here compressed ambient air (compressed air), can be introduced into the fluid containers S, K, Rein via the gas outlets 5K, 5R, 5S. The three gas supply lines 4K, 4S, 4R are connected in parallel via a supply line 8 and are connected to the same gas source 6.

As can be seen from the figures, the three fluid containers S, K, R have different depths. The bases (without reference numbers) of the fluid containers S, K, R therefore have a different geodetic height. All gas outlets are arranged at the same distance from the respective bottoms of the fluid containers S, K, R and consequently also have a different geodetic height. At the same time, the fluid containers S, K, R have the same water line (level, water level).

As a result, when the gas source is activated, the ratio of the gas quantities introduced into the fluid containers S, K, R is dependent on the respective hydrostatic pressure acting on the gas outlet 5K, 5S, 5R, which essentially corresponds to the water columns located above the gas outlets , cf. the hydrostatic heights a, b, c in 4A . Since the hydrostatic pressure is lowest in the middle fluid container S, the air preferentially flows into the middle fluid container S, while less air is introduced into the left fluid container K and almost no air is introduced into the right fluid container R. This results in undesired deposits 12 on the bottom of the fluid containers K and R, which are not or only poorly ventilated, as is shown in 4B is sketched.

Mammoth pumps 7K, 7R, 7S, referred to as compressed air lifters, can also be used in order to be able to dispense with complex control devices, in which the supply pressure for each gas supply is adjusted taking into account the respective hydrostatic pressure acting on the gas outlets 5K, 5S, 5R by means of pressure reducers, for example are used in the embodiments of 5 and 6 are each fully introduced into the fluid containers K, S, R and reach close to the bottom of the respective fluid container.

In the simplest case, mammoth pumps are simple tubes into which a gas inlet with a gas outlet is inserted at a certain height. The gas outlets 5R, 5K, 5S are in the embodiments of FIG 5 and 6 each mounted at the same geodetic height, which is why the pressure conditions at/at all gas outlets 5R, 5K, 5S are the same. As a result, the amount of gas introduced into all fluid containers K, S, R is the same.

The gas introduced under pressure can expand in the mammoth pumps 7K, 7R, 7S, rises upwards and thus creates a suction, which acts through the pipes down to the floor level of the fluid containers K, S, R, the lower water layers together with any existing there Sediments from bottom to top promotes and mixes the lower water layers with the upper water layers. The mammoth pumps can therefore also be referred to as a mixing device.

Due to the different lengths of the mammoth pumps, even fluid containers of different depths can be supplied with a gas from the same gas source from a common gas source without intermediate pressure control devices.

6 shows a variant of the embodiment 5 , Which essentially only differs from the mammoth pump 7R in the exemplary embodiment of FIG 5 differs. In contrast to the other tubular (hollow-cylindrical) mammoth pumps 7K, 7S, the mammoth pump 7R is provided with a trumpet-like inlet at its lower end, which significantly increases the suction effect or the catchment area, so that - unlike in the exemplary embodiment of 5 - Even areas of the ground that are further away are affected by the suction effect. Mammoth pumps with a trumpet-shaped inlet area are particularly suitable for use in fluid containers ter with large base areas and for fluid containers with irregular cross-sections, eg star-shaped cross-sections, which can hardly be managed efficiently by, for example, mechanical mixing devices such as stirrers. A specific embodiment of a mixing device with a trumpet-shaped inlet area is described below in connection with the 2 and 3A/B described.

1 shows a schematic sketch of an exemplary embodiment of a waste water treatment device designed as part of a sewage treatment plant, which consists of a first and a second first and second fluid container, the selector S and the reactor R, which are fluidically connected in series. The waste water treatment device is operated in what is known as a batch operation with a successive loading and aeration phase, a sedimentation phase and a discharge phase.

During the loading and aeration phase, waste water W to be treated is fed into the selector S via an inlet arranged in the selector S, from where it flows into the reactor R once a predetermined level has been reached, namely the overflow edge marked 2. Selector and reactor R both have, for example, a depth Hmax(S) or Hmax(R) of 6 m from an upper edge of the fluid container or a depth of 5 m calculated from the overflow edge 2. The overflow edge 2 is formed by the upper edge of a partition 2' located between the selector S and the reactor R. The overflow edge 2 extends horizontally in a straight line, i.e. it has a constant height.

The level in the selector S and reactor R is in the 1 marked with 3S or 3R. At the in the 1 The state shown is the loading and aeration phase, in which the selector S is loaded with water to be treated, so that the level 3S in the selector S remains essentially unchanged at the level of the overflow edge 2, while the level 3R of the reactor R constantly increasing. During this phase, compressed air is introduced into the fluid containers S, R via two gas outlets 5S and 5R arranged in the selector S and reactor R, respectively. The gas outlet 5S of the selector S is arranged at a height H5S relative to the base 11S of the selector S and is at a hydrostatic height a. The hydrostatic height a is defined by the water column currently located above the gas outlet 5S. In an analogous manner, the gas outlet 5R of the reactor R is at a height 5R above the bottom 11R of the reactor R. It has a hydrostatic height b, which results from the water column above the gas outlet 5R.

The water column above the gas outlet 5S of the selector S remains largely unchanged over the entire charging and aeration phase and only rises when the filling level 3R in the reactor R also reaches the height of the overflow edge 2, i.e. 5m. From then on, the level 3S of the selector S and the reactor R rise together. The range of fluctuation between the level at the height of the overflow edge 2, ie 5 m, and the maximum filling level, ie 6 m, is relatively small compared to the depth of the fluid container at 1 m.

The water column above the gas outlet 5R of the reactor R rises as the water level 3R in the reactor R increases. Since water is withdrawn down to a minimum water level Hmin(R) only from the reactor R, but not from the selector S, in the withdrawal phase explained in more detail below , the level 3R in the reactor R rises and falls cyclically over each cycle of the charging and aeration phase, the sedimentation phase and the withdrawal phase.

The fluctuating level 3R in the reactor R results in a fluctuating hydrostatic height b of the gas outlet 5R in the reactor R or fluctuating hydrostatic pressures at the level of the gas outlet 5R of the reactor R. Since the hydrostatic height a at the gas outlet 5S of the selector is in Essentially remains constant, there is a fluctuating pressure ratio of the pressures at the gas outlet 5S of the selector S and the gas outlet 5R of the reactor R.

Both the selector S and the reactor R should be supplied with certain minimum amounts of air. The air in the selector S should carry as little oxygen as possible and mainly mix it, the air in the reactor R should mainly serve to transfer oxygen. The oxygen requirement results, among other things, from the compounds present in the water to be treated (wastewater), which can be converted by oxidation and are described, for example, with the index of the biochemical oxygen requirement and the chemical oxygen requirement (BOD or COD). But other factors, such as the amount of ammonium in the water, can also have an impact on the oxygen requirement.

In the present case, the selector S serves primarily as an adsorption tank, in which the water in it is mixed with the so-called activated sludge with air blown in via the gas outlet 5S, and the organic compounds are partially converted anoxically or simply adsorbed on the biomass or in this is absorbed. Thorough mixing of the activated sludge that settles, especially on the bottom of the selector S, is therefore particularly important. The sour The material requirement in the selector S is correspondingly high, but is intentionally not covered by the amount of air introduced.

In contrast, the reactor R serves as an aerated activation tank, since the water that has already been pretreated in the selector S reaches the reactor R via the overflow edge 2 . The reactor R is therefore primarily used to activate subsequent processes, including denitrification, i.e. the conversion of nitrate to gaseous nitrogen and many other processes that contribute to the most extensive degradation of organic compounds as part of targeted biomass growth. These processes mainly take place at equilibrium concentrations that are significantly lower than in the case of the selector S. Therefore, the volume of the reactor R is usually a multiple of the volume of the selector S.

Due to these different requirements, the gas outlet 5S of the selector is positioned hydrostatically higher (hydrostatic head a) than the gas outlet 5R of the reactor R (hydrostatic head b) at any water level. A significantly larger dimensioned gas supply line 4R in the reactor R than the supply line 4S in the selector S means that the rate of entry of compressed air or oxygen into the reactor R is correspondingly higher than into the selector S, although both gas outlets 5R, 5S are their gas supplies 4S or 4R are connected to the same gas source 6 via a common supply line 8 and there is no pressure reducer or regulator for controlling the amount of gas introduced in one of the gas supplies 4R, 4S, i.e. both gas supplies 4S, 4R are supplied with compressed air at the same supply pressure . Due to the different type of gas introduction - into the selector S through a mixing device 7, described in more detail below, with a very coarse-bubble aeration on the one hand, and mostly very small gas outlets 5R in the reactor R with a rather fine-bubble aeration on the other side - results there is always a significantly higher oxygen transfer into the reactor R than into the selector S. This is also due to the fact that the oxygen transfer into the reactor R is determined by the partial pressure, which in turn depends on the hydrostatic pressure b in the reactor R, which is higher than the hydrostatic pressure a in the selector S is always greater.

Specifically, the gas outlet 5R of the reactor is near the bottom about 30cm above the bottom of the reactor R (reference H5R) while the gas outlet 5S of the selector S is about 0.5-1.5m above the bottom of the selector S (reference H5S). At a distance of 0.5-1.5 m from the bottom, it would not be possible to whirl up and mix the activated sludge on the bottom of the selector S with the air supply alone, so the gas outlet 5S is installed in the mixing device 7 designed as a mammoth pump.

The mixing device 7 is with reference to the 2 and 3A until 3C described in more detail. It essentially consists of a two-part, waveguide-like base body with a lateral surface M, which defines a flow channel 15 between a vertically lower inlet 9 and an upper outlet 10 . The base body extends along a vertically arranged longitudinal axis X and is 3.5 m long. The main body is under water; the outlet is located about 100 cm below the overflow edge 2 (reference H10). The lateral surface M is essentially not perforated, in particular it has no openings or inlets through which water could flow into or out of the flow channel 15 (the inlet opening of the inlet 9 and the outlet opening of the outlet 10 excepted).

The base body consists of a lower funnel-shaped section 7B--also called the inlet area--with a length L7B of 70 cm and an adjoining tubular section 7A with a length L7A of 3 m. These two parts are placed on top of each other in an overlapping manner with an overlap of 20 cm and are detachably connected to one another with screws (cf. the screws in 2 and 3A ). The screws are also used to fasten stand brackets 14b assigned to a fastening device 14 to the base body, via which the base body can be anchored firmly to the base 11S of the selector S at a distance H9 of 50 cm from the base 11S of the selector S. In addition, the base body is secured in the selector S via tensioning cables 14a of the fastening device 14, which engage further up on the tubular section 7A, so that the base body is aligned substantially vertically in the selector S.

At the level of the lower third of the mixing device 7 - based on the overall length L measured in the longitudinal direction of the longitudinal axis X - the gas outlet 5S is arranged, which is screwed into the wall of the tubular section 7A like a sleeve and ends essentially flush with the wall. It is therefore practically impossible for solid bodies carried along in the fluid flow to become lodged and for a consequent blockage to occur.

The air supply is eccentric. In the exemplary embodiment shown, its height cannot be changed. In others not shown In some embodiments, the air supply, i.e. in particular the gas outlet, can be designed to be variable in height or at least have a large number of gas outlets positioned at different heights, of which only one gas outlet is connected to the gas source, while the others are closed as so-called blind outlets or . are.

In addition, a fluid guide device 13 consisting of two baffles is detachably fastened via screws in the tubular section 7A above the gas feed line 5S. The baffles are sickle-shaped, arranged at an angle to the vertical and one above the other and rotated by 180° with respect to the longitudinal axis X, so that water rising in the tubular section 7A is set in rotation with respect to the longitudinal axis X. The fluid guide device 13 is dimensioned in such a way that it continues below the gas outlet opening 5S in any case, but leaves a cylindrical section of the flow channel 15 untouched in the middle of the tubular section 7A, so that part of the fluid flow can flow directly, i.e. vertically, through the mixing device 7 can flow. This is good in the top view of the 3C to recognize. As a result, a spiral suction of the fluid is achieved, which continues downwards to the suction opening 9 and, moreover, induces a spiral suction movement in the fluid layers close to the pelvic floor of the selector S.

The tubular portion 7A is cone-shaped (cone-section-shaped) and has, as esp 2 evident, an opening angle of 2α. The opening angle 2a is about 5°. This allows multiple tubular sections to be stacked on top of each other in a space-saving manner when not installed. The conical section 7A is made from sheet metal which has been bent into a tubular shape and has been soldered to form a material bond at its longitudinal edges.

The funnel-shaped section 7B located at the bottom is trumpet-like, i.e. rounded with a parabolic contour, which is conducive to laminar flow conditions without flow breaks in the inlet area. At its outer end of the inlet 9, the funnel-shaped section has an angle β of 45°. The funnel-shaped portion 7B is made of glass fiber reinforced polyester resin plastic by plastic injection molding. Other materials are possible.

The inlet opening in the inlet 9 is circular, has a diameter D9 of 80 cm, and is aligned perpendicular to the longitudinal axis, i.e. horizontally. The inlet opening of the inlet 9 is 20cm (H9) above the ground. The inlet opening forms the beginning of the flow channel of the mixing device 7. The flow channel narrows as a result of the trumpet-like inlet, initially down to 50 cm at the upper end of the funnel-shaped section 7B and then further to around 40 cm up to the outlet at the upper end of the tubular section 7A. Similar to the inlet, the outlet consists of a circular outlet opening with a diameter D10 of 40 cm and is arranged horizontally.

The floors of the reactor R and the selector S are in the embodiment of the 1 flat and are at the same geodetic height (H0(R) = H0(S)). However, the inventive concept can also be transferred to fluid containers in which the bottoms of the fluid containers are located at different geodetic heights or are uneven, for example funnel-shaped.

For all the above statements, it applies that the vessels referred to as fluid containers are not fluid containers in the laboratory sense, i.e. in particular not transportable (hand) containers, but permanently installed basins with a capacity of several cubic meters, preferably in one area from 15m ³ upwards, but less than 30,000m ³ . The pools are usually arranged outdoors and not covered.

Reference List

D9

Opening cross section inlet opening

D10

Opening cross-section outlet opening

H0

height floor

H5R

vertical distance gas inlet

H5S

vertical distance gas inlet

Hmax

Maximum level

hmm

minimum level

H9

height of the inlet

H10

height of the spout

a

Fluid column ('hydrostatic head')

b

Fluid column ('hydrostatic head')

c

Fluid column ('hydrostatic head')

K

captor

L

longitudinal extent

M

lateral surface

R

reactor

S

selector

W

water

X

longitudinal axis

1

water treatment device

2

overflow edge

2'

partition wall

3R

level

3S

level

4S

gas supply

4R

gas supply

5S

gas outlet

5R

gas outlet

5K

gas outlet

6

gas source

7

mixing device

7A

tubular section

7B

funnel section

8th

supply line (gas)

9

enema

10

outlet

11R

floor

11S

floor

12

sediments

13

fluid guide device

14

fastening device

14a

stand angle

14b

tension rope

15

flow channel

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 2943870 A1 [0004]
• US4663044 [0036]

Claims (15)

Mixing device (7) working according to the principle of a mammoth pump for circulating a fluid (W) in a fluid container (S) filled with the fluid from a first level (H9) to a second level (H10) with a longitudinal axis (X). extending, waveguide-like base body forming a flow channel (15) with a lateral surface (M), comprising an inlet (9) located at a lower end for sucking in the fluid and an outlet (10) located at an upper end for dispensing the fluid (W) and a gas outlet (5S) located therebetween for blowing in a gas to generate suction at the inlet (9), the inlet (9) being arranged in a funnel-shaped inlet area (7B), the outlet (10) being arranged in a tubular section (7A) is arranged, and the funnel-shaped inlet area (7B) and the tubular section (7A) form the flow channel (15), characterized in that the base body is formed in two parts is such that the inlet area (7B) and the tubular section (7A) each form an independent component which are connected to one another to form the base body. Mixing device (7) after claim 1 , characterized in that the tubular section (7A) for better transportability is designed as a conical section with a sloping lateral surface, in particular with an inclination (α) to the vertical of between 1:0.005 and 1:0.05. Mixing device (7) after claim 1 or 2 , characterized in that the tubular section (7A) and the inlet area (7B) are detachably connected to one another for better transportability. Mixing device (7) according to one of the preceding claims, characterized in that the inlet area (7B) is rounded, in particular with a hyperbolic or parabolic contour, with the lateral surface of the inlet (9) having an inclination (β) of at most 45° of the vertical. Mixing device (7) according to one of the preceding claims, characterized in that the inlet (9) has an opening cross section (D9) which corresponds to at least twice the opening cross section (D10) of the outlet (10). Mixing device (7) according to one of the preceding claims, characterized in that the tubular section (7A) is designed as a closed lateral surface without interruptions or openings. Mixing device (7) according to one of the preceding claims, characterized in that the mixing device (7) comprises a fluid guide device (13) detachably arranged in the tubular section (7A) for generating a rotating flow field, in particular in the form of a helical insert. Mixing device (7) after claim 7 , characterized in that the fluid guide device (13) has a section which extends below the gas outlet (5B). Mixing device (7) after claim 7 or 8th , characterized in that the fluid guide device (13) extends along the lateral surface (M) of the base body, but does not completely cover the flow channel (15) viewed in cross section, so that a central part of the flow channel (15) remains open, through which the fluid can flow can flow directly from the inlet (9) to the outlet (10). Mixing device (7) according to one of the preceding claims, characterized in that the gas outlet (5S) opens directly into the lateral surface (M) of the tubular section (7A) and ends essentially flush with the lateral surface (M) in order to act as a flow obstacle to minimize. Mixing device (7) according to one of the preceding claims, characterized in that the gas outlet (5S) is arranged in the lower half, preferably the lower third, based on the overall length (L) of the mixing device (7), and at a distance from the inlet (9) from 20-150cm. Mixing device (7) according to one of the preceding claims, characterized in that the overall length (L) of the mixing device (7) corresponds to at least four times the opening cross section (D 10) of the outlet (10). Mixing device (7) according to one of the preceding claims, characterized in that the mixing device (7) has an overall length (L) of between 1.5 and 4 m. Mixing device (7) according to one of the preceding claims, characterized in that the funnel-shaped inlet area (7B) and optionally also the tubular section (7A) are made of a plastic. Use of a mixing device (7) according to one of the preceding claims in a water treatment device (1).

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