Device and method for gassing a liquid

Abstract

A device for gassing a liquid, comprising a rotor (1) which is driven in rotation about a vertical axis of rotation and has a plurality of vanes (10) for conveying the liquid, and a stator (2) surrounding the rotor (1) and having a plurality of flow channels (20), each of which runs from a radially inner inlet opening (21) adjacent to the rotor (1) through the stator (2) to a radially outer outlet opening (22), and is delimited along its length by side walls, base and ceiling surfaces, and can be supplied with liquid by the rotor (1) in the region of the inlet opening (21), characterized in that the side walls and / or base and ceiling surfaces of 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 compressed gas from a compressed gas source in order to introduce said gas into the flow channels (20).

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 with 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.

[0002] The invention further relates to a method for gassing a liquid, in which the liquid is conveyed by a rotor with a plurality of blades, which is driven in rotation about a vertical axis of rotation, into flow channels of a stator surrounding the rotor, which flow channels each extend 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.

[0003] Devices and methods 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.

[0004] In order to be able to gasify 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.

[0005] From DE 16 67 042 A 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.

[0006] 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 gas supply pipeline can also be connected to a compressed gas source to increase the volume of air introduced.

[0007] DE 39 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.

[0008] 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.

[0009] A disadvantage of these known devices is that the mixing of the gas components with the liquid usually occurs in the region of the rotor, i.e., before the gas-liquid mixture enters the flow channels of the stator. This results in a significant loss of flow energy, so 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 requiring gasification, for example, in vinegar production, since uniform, fine-particle gassing of the entire liquid volume cannot be achieved.

[0010] 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.

[0011] The object of the invention is therefore to propose a device and a method of the type mentioned at the outset which overcome the disadvantages of the prior art and enable a particularly uniform and intensive gassing of a liquid with little structural effort.

[0012] To achieve the stated object, the invention proposes the design of a device according to the characterizing features of patent claim 1.

[0013] A method for solving the problem is the subject of patent claim 9.

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

[0015] To achieve the stated object, the invention proposes a device which is designed such that the side walls and / or floor and ceiling surfaces of 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.

[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 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 volumes of gas 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, through which the liquid is conveyed by the rotor's action. Energy losses in the rotor drive area are thus significantly reduced.

[0019] According to a proposal of the invention, it is provided that a separating element is arranged between adjacent flow channels of the stator, which separating element has side surfaces which each 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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 in an exchangeable manner. This design simplifies the mechanical manufacture of the stator, and the separating elements can be easily replaced, for example, in the event of wear. 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.

[0024] Furthermore, particularly in designs where 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.

[0025] The separating elements can have various suitable shapes. A wedge-shaped separating element is considered particularly advantageous, with the wedge tip pointing toward the rotor.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] The inventive method for gassing a liquid is based on the liquid being 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 and ceiling surfaces. According to the invention, gas from a compressed gas source is introduced into the flow channels in the region between the inlet opening and the outlet opening from gassing openings in the side walls and / or floor and ceiling surfaces and is mixed with the liquid flowing through the flow channels as it passes through the flow channels.

[0030] In addition, it can be provided that the gas is introduced into the flow channels transversely to the flow direction of the liquid in order to improve mixing.

[0031] Further embodiments and details of the device and method according to the invention are explained below using an exemplary embodiment in the drawing. They show: Fig. 1 a plan view of a device according to the invention; Fig. 2 the section through the device according to Fig. 1 along line AA; Fig. 3 shows a perspective view of a partially disassembled device according to Fig. 1.

[0032] From the Fig. 1 to 3 show a device for gassing a liquid, for example, usable as an aerator for a vinegar fermenter in vinegar production.

[0033] 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 Fig. 1 rotates according to arrow D.

[0034] The rotor 1 is surrounded radially on the outside by a stator 2, which, extending from a mounting flange 23 on the underside, comprises a circular lower stator plate 26 and a likewise 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 are replaceably fastened 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.

[0035] 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 as well as 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.

[0036] As can be seen in particular from the illustration in accordance with Fig. 1, the upper stator plate 27 of the stator 2 is annular and has a central through-bore as a liquid inlet 270, through which the vanes 10 and the vane spaces 11 remaining between the vanes 10 are accessible.

[0037] 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 sealed in 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.

[0038] As a result of the rotation of the rotor 1, liquid flows from the container via the liquid inlet 270 into the operating 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.

[0039] 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 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.

[0040] 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.

[0041] 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.

[0042] 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, as well as 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 into the individual flow channels 20 via the gassing openings 24 in the respective perforated plates 251.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, wherein the outlet direction of the gas from the gassing openings 24 runs transversely to the flow direction of the liquid in the flow channel 20.

[0043] 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.

[0044] In this way, it is possible, for example, to create a 140 m 3Liquid-holding containers with up to 1,500 m 3 Gas per hour in finely dispersed form, whereby depending on the container volume, liquid and gas, about 6-12 m 3 / h gas volume per cubic meter of container volume can be distributed in the liquid.

[0045] 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.

[0046] 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 Fig. 1 and Fig.As can be seen in Figure 2, a liquid inlet 3 is provided centrally above the rotor 1 and the liquid inlet 270 in the upper stator plate 27. This liquid inlet 3 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, from where it is drawn into the flow channels 20 and from there evenly distributed in the container. Furthermore, the vertically standing retaining plates 30 counteract the formation of an undesirable cyclone flow in the container.

[0047] 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.

[0048] The device and the method are 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) which is driven in rotation about a vertical axis of rotation and has a plurality of vanes (10) for conveying the liquid, and a stator (2) surrounding the rotor (1) with a plurality of flow channels (20), each of which runs from a radially inner inlet opening (21) adjacent to the rotor (1) through the stator (2) to a radially outer outlet opening (22) and is delimited along its course by side walls, floor and ceiling surfaces and can be supplied with liquid by the rotor (1) in the region of the inlet opening (21), characterized by that the side walls and / or floor and ceiling surfaces of 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 compressed gas from a compressed gas source in order to introduce this into the flow channels (20). [2] Device according to claim 1, characterized by that between adjacent flow channels (20) there is arranged in each case a separating element (25) with side surfaces (250), which in each case form at least a partial section of a side wall of one or both adjacent flow channels (20), and the gassing openings (24) are formed in the side surface (250). [3] Device according to claim 2, characterized by that the separating elements (25) are formed with an inner hollow chamber which communicates with the compressed gas source and a perforated plate (251) having the gassing openings (24) is received in the side surfaces (250) of the separating elements (25). [4] Device according to one of claims 1 to 3, characterized by that the gassing openings (24) are arranged adjacent to the outlet opening (22) of the flow channels (20). [5] Device according to one of claims 2 to 4, characterized bythat the stator (2) comprises a lower stator plate (26) and an upper stator plate (27), between which the separating elements (25) are arranged in an exchangeable manner and the lower and upper stator plates (26, 27) each form the bottom and top surfaces of the flow channels (20) between the separating elements (25). [6] Device according to claim 5, characterized by that the lower stator plate (26) has a circumferential gas distribution channel (260) connected to a central gas inlet (261) which communicates with the gassing openings (24). [7] Device according to one of claims 2 to 6, characterized by that the separating elements (25) are wedge-shaped. [8] Device according to one of claims 1 to 6, characterized by that the gassing openings (24) have a diameter of at most 1 mm and that up to 2000 gassing openings (24) are assigned to each flow channel (20). [9] Method for gassing a liquid, in which the liquid is conveyed by a rotor (1) with a plurality of vanes (10) which is driven in rotation about a vertical axis of rotation into flow channels of a stator (2) surrounding the rotor (1), which flow channels each extend from a radially 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, floor and ceiling surfaces, characterized by that gas from a compressed gas source is introduced into the flow channels (20) in the area between the inlet opening (21) and the outlet opening (22) from gassing openings (24) in the side walls and / or floor and ceiling surfaces and is mixed with the liquid flowing through the flow channels (20) during passage through the flow channels (20). [10] Method according to claim 9, characterized bythat the gas is introduced into the flow channels perpendicular to the flow direction of the liquid.

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