Device for gassing a liquid

Abstract

The invention relates to a device for aerating a liquid, comprising a rotary-driven rotor (1) with several vanes (10) for conveying the liquid and a stator (2) surrounding the rotor (1) with a plurality of flow channels (20), each extending from a radially inner inlet opening (21) adjacent to the rotor (1) through the stator (2) to a radially outer outlet opening (22) and bounded along its course by side walls, bottom and top surfaces and in the region of the inlet opening (21) can be supplied with liquid by the rotor (1), wherein the side walls and / or bottom and top surfaces of the flow channels (20) between the inlet opening (21) and the outlet opening (22) have a plurality of aeration openings (24) which can be supplied with pressurized gas from a pressurized gas source in order to introduce it into the flow channels (20).Furthermore, a corresponding procedure for gassing a liquid is also described.

Description

[0001] The invention relates to a device for gassing a liquid, comprising a rotor which is driven in rotation about a vertical axis of rotation and has a plurality of blades for conveying the liquid and a stator surrounding the rotor and having a plurality of flow channels which each run from a radially inner inlet opening adjacent to the rotor through the stator to a radially outer outlet opening and are delimited along their course by side walls, floor and ceiling surfaces and can be supplied with liquid by the rotor in the region of the inlet opening, wherein the flow channels between the inlet opening and the outlet opening have a plurality of gassing openings which can be supplied with compressed gas from a compressed gas source in order to introduce this into the flow channels.

[0002] Devices of the type mentioned above are known and are used, for example, to introduce air into a vinegar fermenter during vinegar production. This fermenter contains an aqueous alcohol solution that is converted into vinegar by aerobic bacteria. These bacteria have a high, permanent oxygen demand.

[0003] In order to be able to gas the liquid with sufficient volume, for example, to introduce oxygen into such an alcohol solution, devices are known that have a rotary-driven rotor with multiple vanes for conveying the liquid radially outward into a stator surrounding the rotor. The stator has a plurality of flow channels through which the liquid flows, driven by the rotor.

[0004] From DE 1 667 042 A1 it is known to automatically suck in air from the rotor in addition to the liquid and to distribute it in the liquid to be aerated before it enters the flow channels, so that a liquid-air mixture with finely distributed gas bubbles emerges from the flow channels.

[0005] Furthermore, DE 298 19 704 U1 discloses supplying the gas, for example, air, to the rotor via a pipeline and mixing it with the separately supplied liquid in the rotor, in order to then distribute the resulting gas-liquid mixture homogeneously through the flow channels of the stator. In known embodiments, the pipeline for the gas supply can also be connected to a compressed gas source to increase the volume of air introduced.

[0006] DE39 05 211 A1 discloses a gassing device for liquids, in which the gas is introduced into the liquid flow guided through side walls as well as floor and ceiling surfaces according to the injector principle and mixed with the liquid.

[0007] DE 24 17 536 A describes a device with a liquid container and a stirrer rotating around a vertical axis. A gas stream can be supplied below the stirrer.

[0008] A disadvantage of these known devices is that the mixing of the gas components with the liquid usually takes place in the area of the rotor, i.e. before the gas-liquid mixture enters the flow channels of the stator. This entails a considerable loss of flow energy, meaning that such systems can only be operated in an energy-inefficient manner, which appears to be in need of improvement. Furthermore, the amount of gas that can be introduced is limited, particularly in self-priming devices. Simply blowing compressed air into the liquid volume in the container often proves inadequate for critical liquids that require gassing, for example in vinegar production, since uniform, fine-particle gassing of the entire liquid volume cannot be achieved.

[0009] If a self-priming device is additionally pressurized with compressed gas, e.g. compressed air from a compressor, in the area of the suction line, increasing pressure is accompanied by a reduction in the delivery capacity of the rotor, which leads to an undesirably high loss of drive energy of the rotor.

[0010] US Pat. No. 3,815,879 A discloses a device according to the preamble of claim 1 for gassing a liquid. In this device, several rotors arranged one above the other and on a common rotor axis convey liquid into a cylinder surrounding the respective rotor, which cylinder has radially outward-facing flow channels for the conveyed liquid. Furthermore, a gassing opening opens into the respective base region of the flow channels, through which gas can be introduced into the liquid flow.

[0011] A similar gassing device is known from US 4 193 950 A, in which radially outward-leading flow channels are arranged in a stator surrounding the rotor on the radial outside of a multi-level rotor, wherein the bottom and top surfaces of the flow channels have a wing-like profile cross-section and form Venturi nozzles, via which gas is introduced into the liquid flow through gas-permeable inserts inserted in the bottom and top area.

[0012] The object of the invention is therefore to propose a device of the type mentioned at the outset which overcomes the disadvantages of the prior art and enables a particularly uniform and intensive gassing of a liquid with little structural effort.

[0013] To achieve the stated object, the invention proposes the design of a device according to the characterizing features of patent claim 1.

[0014] Advantageous embodiments and further developments of the invention are the subject of the dependent claims.

[0015] To achieve the stated object, the invention proposes a device which is designed in such a way that a wedge-shaped separating element with side surfaces is arranged between adjacent flow channels, which in each case form at least a partial section of a side wall of one or both adjacent flow channels and the gassing openings are formed in the side surface and wherein the tips of the wedge-shaped separating elements each point in the direction of the rotor.

[0016] In the device according to the invention, the rotor therefore only serves to convey the liquid into the flow channels and only in the flow channels is the liquid exposed to the compressed gas from a compressed gas source on the way from the inlet opening to the outlet opening, which gas enters the flow channels via the gassing openings in the side surfaces of the wedge-shaped separating elements and mixes there with the liquid.

[0017] Within the scope of the invention, it has been shown that such a rotor design exerts a particularly high flow rate and intensive stirring effect on the liquid, while simultaneously allowing large gas volumes to be introduced into the liquid flowing through the flow channels. A very finely distributed and homogeneous gas-liquid mixture subsequently emerges from the flow channels.

[0018] In contrast to the conventional mixing of gas and liquid components in the rotor's operating area, this mixing of gas and liquid components is relocated to the area of the flow channels, into which the liquid is conveyed by the rotor's action. Energy losses in the rotor drive area are thus significantly reduced.

[0019] In particular, it is preferred if such separating elements with their side surfaces each form a complete side wall of the adjacent flow channels, so that the stator is characterized by a design in which flow channels arranged in a ring-like manner one after the other are each separated by a separating element, ie flow channels and separating elements alternate over the circumference of the usually round stator.

[0020] According to one proposal of the invention, the separating elements can be designed with an inner hollow chamber that communicates with the compressed gas source via corresponding supply lines, and a perforated plate with gas vents is accommodated in the side surfaces of the separating elements. This allows for particularly efficient production, since the separating elements can be prefabricated accordingly, including the hollow chamber. Depending on the design, corresponding perforated plates with a specifically calculated number and dimensions of gas vents are inserted into the corresponding receptacles in the side surfaces. When inserted into the receptacle, the perforated plate preferably continues flush with the surrounding side surface.

[0021] According to a further proposal of the invention, the gassing openings are preferably arranged adjacent to the outlet opening of the flow channels, i.e., they are spaced further apart from the inlet openings than from the outlet opening of the individual flow channels. The liquid flow generated by the rotor through the flow channel thus has the opportunity to initially become uniform after entering through the inlet opening before passing through the gassing openings, through which the compressed gas is introduced into the liquid.

[0022] According to a further proposal of the invention, the stator is constructed in several parts and comprises a lower stator plate and an upper stator plate, between which the separating elements are arranged so as to be replaceable. This design simplifies the mechanical manufacture of the stator and the separating elements can be easily replaced, for example when they become worn. For this purpose, they can be screwed onto the lower stator plate, for example. In any case, the lower and upper stator plates in such an arrangement each form the bottom and top surfaces of the flow channels between the separating elements, i.e. they jointly cover them on the top and bottom.

[0023] Furthermore, particularly in designs in which the separating elements are interchangeably mounted on the lower stator plate, this lower stator plate is provided with a circumferential gas distribution channel connected to a central gas inlet, which communicates with the gas supply openings via the individual separating elements. Of course, such an arrangement could also be provided in the area of the upper stator plate, in which case the separating elements would then advantageously also be attached to the upper stator plate.

[0024] The separating elements can have various suitable shapes and are designed in the manner of a wedge, with the wedge tip pointing in the direction of the rotor.

[0025] The gassing openings can be dimensioned depending on the type and requirements of the liquid to be gassed and should preferably have a diameter of no more than 1 mm to prevent the formation of undesirably large gas bubbles in the liquid. Furthermore, each flow channel can have a plurality of gassing openings, in particular between 200 and 2000 gassing openings, which are arranged in the respective side walls, and optionally also in the floor and / or ceiling surfaces of the flow channel.

[0026] It is preferred that corresponding gassing openings are arranged in both side walls facing each other and delimiting the flow channel, if necessary also additionally in the area of the floor surface and in exceptional cases also in the area of the ceiling surfaces.

[0027] In particular, when the device is used in the context of vinegar production, air from a compressor can be provided as the compressed gas for the device according to the invention, which in this respect serves as a compressed gas source.

[0028] The device according to the invention for gassing a liquid is based on the fact that the liquid is conveyed by a rotationally driven rotor with multiple blades into flow channels of a stator surrounding the rotor. The flow channels each run from a radially inner inlet opening adjacent to the rotor through the stator to a radially outer outlet opening and are delimited along their course by side walls, floor surfaces, and ceiling surfaces. Gas from a compressed gas source is introduced into the flow channels in the area between the inlet opening and the outlet opening from gassing openings in the side walls and is mixed with the liquid flowing through the flow channels as it passes through the flow channels.

[0029] In addition, it is planned that the gas is introduced into the flow channels transversely to the flow direction of the liquid in order to improve mixing.

[0030] Further embodiments and details of the device according to the invention are explained below using an exemplary embodiment in the drawing. They show: Figure 1 shows a plan view of a device according to the invention; Figure 2 shows the section through the device according to Figure 1 along the line AA; Figure 3 in perspective view a partially disassembled device according to Figure 1 .

[0031] From the Figures 1 to 3 a device for gassing a liquid, for example, usable as an aerator for a vinegar fermenter in vinegar production, is shown.

[0032] The device comprises a rotor 1 which is driven in rotation by a drive motor (not shown here), which has a plurality of vanes 10, here seven, projecting radially along a curved path and in the Figure 1 rotates in the direction of rotation shown according to arrow D.

[0033] The rotor 1 is surrounded radially on the outside by a stator 2, which, starting from a lower mounting flange 23, comprises a circular lower stator plate 26 and an upper stator plate 27, between which a plurality of wedge-shaped separating elements 25 are arranged, which are designed in a matching manner. These are fixed in a ring-like manner on the lower stator plate 26 at equal distances from one another and can be replaced by means of screws 252. Between each adjacent separating element 25, a flow channel 20 is formed, which runs from the inside to the outside through the stator 2.

[0034] Accordingly, each flow channel 20 comprises an inlet opening 21 adjacent to the rotor 1 and a radially outer outlet opening 22 and is delimited by mutually facing side surfaces 250 of two adjacent separating elements 25 as side walls and by the lower stator plate 26 as the bottom surface and the upper stator plate 27 as the ceiling surface and is thus open towards the inlet opening 21 and the outlet opening 22 for the passage of liquid.

[0035] As can be seen in particular from the illustration in accordance with Figure 1 As can be seen, the upper stator plate 27 of the stator 2 is annular and has a central through-bore as a liquid inlet 270, via which the vanes 10 and the vane spaces 11 remaining between the vanes 10 are accessible.

[0036] When such a device is installed in a container, for example, a vinegar fermenter, the device is located in the bottom area of the container and can be sealingly attached to a corresponding container opening via a flange ring 28 provided radially on the outside. The flange 23, which then lies outside the container, carries the drive motor (not shown here), whose drive shaft engages in the shaft receptacle 12 of the rotor 1 to drive the rotor 1 about a vertically extending rotational axis according to arrow D.

[0037] As a result of the rotation of the rotor 1, liquid flows from the container via the liquid inlet 270 into the effective area of the rotating rotor 1 and is conveyed by the vanes 10 from the vane spaces 11 into the individual flow channels 20 of the stator 2. The inlet openings 21 of the individual flow channels 20 can be located close to the circumferential line of the rotor 1 resulting from rotation, and the tips of the wedge-shaped separating elements 25 each point in the direction of the rotor 1.

[0038] When the rotor 1 rotates, the device thus conveys a high volume flow of liquid via the liquid inlet 270 into the flow channels 20 up to their outlet openings 22, from where the liquid flows back into the container and is evenly distributed in the container due to the circular arrangement of the individual flow channels 20.

[0039] In order to be able to gasse this liquid flow through the individual flow channels 20 with the desired gas volume, the side surfaces 250 of each separating element 25, which each form a side wall of adjacent flow channels 20, are provided with an opening as a receptacle into which a corresponding perforated plate 251 is inserted, which continues the side surface 250 of the separating element 25 flush.

[0040] Each perforated plate 251 is provided with a plurality of gassing openings 24 extending through the perforated plate 251, for example one hundred to one thousand such gassing openings 24 in a regular arrangement, each having a diameter of less than 1 mm.

[0041] The separating elements 25, in turn, are designed with an inner cavity that communicates with the opening in the side surface 250 and the perforated plate 251 received therein and the gassing openings 24 formed therein. The gas intended for gassing can be supplied under high pressure from a compressed gas source, for example air from a compressor, via a central gas inlet 261 on the underside and passes through a circumferential gas distribution channel 260 in the lower stator plate 26 and corresponding connecting bores into each individual cavity of the separating elements 25. From there, the gas flows through the gassing openings 24 in the respective perforated plates 251 into the individual flow channels 20.The arrangement is selected such that the gassing openings 24 are arranged adjacent to the outlet opening 22 of each flow channel 20 and are thus at a greater distance from the inlet opening 21, the outlet direction of the gas from the gassing openings 24 being transverse to the flow direction of the liquid in the flow channel 20.

[0042] Accordingly, when liquid is conveyed into the flow channels 20 by the vanes 10 upon rotation of the rotor 1 in the direction of arrow D, this fluid flow, which initially enters the flow channels 20 as a pure liquid flow via the inlet opening 21, is only exposed to the gas flow from the gassing openings 24, which runs transversely to the flow direction through the flow channel 20, during the course of its passage through the flow channel 20. Since the individual gassing openings are designed with a small diameter of a maximum of 1 mm, gas volume in finely distributed form is introduced into the individual partial flows of the liquid in the flow channels 20 and intensively mixed with the liquid before the gas-liquid mixture thus produced exits the outlet openings 22 of the flow channels 20 into the container.

[0043] In this way, it is possible, for example, to supply a container with a capacity of 140 m 3< of liquid with up to 1,500 m 3< of gas per hour in finely distributed form, whereby, depending on the container volume, liquid and gas, around 6-12 m 3< / h of gas volume per cubic meter of container volume can be distributed in the liquid.

[0044] The stirring effect of the rotor is optimally utilized and, despite the high gas volumes introduced, energy savings of around 30 to 50% can be achieved compared to conventional devices.

[0045] In order to be able to distribute the amount of alcohol added to the container as quickly as possible in the container volume in a vinegar fermenter, for example, it is also necessary, as can be seen from the Figures 1 and 2As can be seen, a liquid inlet 3 is provided centrally above the rotor 1 and the liquid inlet 270 in the upper stator plate 27, which is held above the liquid inlet opening 270 by means of four vertically standing retaining plates 30 arranged at an angle of 90° to one another. This liquid inlet 3 ensures that the supplied quantity of alcohol reaches the rotating rotor 1 directly and is distributed by it into the flow channels 20 and from there evenly in the container. In addition, the vertically standing retaining plates 30 counteract the formation of an undesirable cyclone flow in the container.

[0046] The device explained above is preferably made of corrosion-resistant metal, wherein the finely distributed gassing openings 24 can be introduced into the perforated plates 251, in particular by means of a laser.

[0047] The device is particularly suitable for aerating an alcoholic solution with air during vinegar production, but can also be used for any other gassing tasks of liquids where the homogeneous distribution of large gas volumes in the reacted liquid is desired.

Claims

1. Device for gassing a liquid, comprising a rotor (1) driven in rotation about a vertical axis of rotation with multiple vanes (10) for conveying the liquid, and a stator (2) surrounding the rotor (1) with a plurality of flow channels (20), which each extend from a radial inner inlet opening (21) adjacent to the rotor (1) through the stator (2) to a radially outer outlet opening (22) and are delimited along their course by side walls, bottom and top surfaces and can be supplied with liquid by the rotor (1) in the region of the inlet opening (21), wherein the flow channels (20) between the inlet opening (21) and the outlet opening (22) have a plurality of gassing openings (24), which can be supplied with pressurized gas from a pressurized gas source in order to introduce this into the flow channels (20), characterized in that a wedge-shaped dividing element (25) with side surfaces (250) is arranged between adjacent flow channels (20), which side surfaces each form at least a portion of a side wall of one or both adjacent flow channels (20) and the gassing openings (24) are formed in the side surface (250) and wherein the tips of the wedge-shaped dividing elements (25) each point in the direction of the rotor (1).

2. Device according to claim 1, characterized in that the dividing elements (25) are configured to have an inner cavity, which communicates with the pressurized gas source, and a perforated plate (251) with the gassing openings (24) is accommodated in the side surfaces (250) of the dividing elements (25).

3. Device according to any one of claims 1 or 2, characterized in that the gassing openings (24) are arranged adjacent to the outlet opening (22) of the flow channels (20).

4. Device according to any one of claims 1 to 3, characterized in that the stator (2) comprises a lower stator plate (26) and an upper stator plate (27), between which the dividing elements (25) are arranged so as to be replaceable and the lower and upper stator plate (26, 27) form the respective bottom and top surfaces of the flow channels (20) between the dividing elements (25).

5. Device according to claim 4, characterized in that the lower stator plate (26) has a circumferential gas dispersion channel (260) connected to a central gas inlet (261) and communicates with the gassing openings (24).

6. Device according to any one of claims 1 to 5, characterized in that the gassing openings (24) have a diameter of at most 1 mm and each flow channel (20) is associated with up to 2000 gassing openings (24).

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