Double pipe ventilation element and ventilation system

Abstract

Double-pipe ventilation element (1) for deacidifying water, comprising at least one horizontally oriented inner pipe (2) with inner pipe ventilation openings (6) on the underside of the inner pipe (2) and an air inlet opening for introducing air into the inner pipe (2), wherein the double-pipe ventilation element (1) further comprises an outer pipe (3) which has outer pipe ventilation openings (7) on the top side and at least one drainage opening on the underside, wherein the sum of the areas of the inner pipe ventilation openings (6) of the inner pipes (2) is greater than or equal to the sum of the areas of the outer pipe ventilation openings (7) of the outer pipe (3) and the inner pipe (2) is arranged inside the outer pipe (3) such that an evenly distributed air cushion is formed over the length of the outer pipe (3) below the outer pipe ventilation openings (7) on the top side of the outer pipe (3).

Description

[0001] The invention relates to a double-pipe ventilation element for introducing gases into liquids, for example suitable for deacidifying water by blowing in air, comprising at least one horizontally oriented inner pipe with inner pipe ventilation openings on the underside of the inner pipe as well as an air inlet opening for introducing air into the inner pipe and an outer pipe with outer pipe ventilation openings, as well as a ventilation system with at least one double-pipe ventilation element.

[0002] These types of aeration elements are used particularly in the treatment of raw water. To treat water for use as drinking or process water, it is generally necessary to establish calcium carbonate equilibrium. Natural waters are often not in calcium carbonate equilibrium; instead, they frequently contain an excessively high proportion of aggressive carbonic acid, which is corrosive to some materials, such as iron.

[0003] Treatment of this highly corrosive water, due to its high carbonic acid content, is necessary and can be achieved, for example, through deacidification. This process reduces the carbon dioxide content in the water, thereby raising the pH value. The energy required for desorption is supplied to the carbon dioxide by introducing air. The air is introduced into the water in the form of fine bubbles. This allows the carbon dioxide to overcome its binding energy and desorb. Thus, by introducing air into the water, carbon dioxide is removed.

[0004] To achieve effective deacidification, it is necessary to generate constant, very fine air bubbles. In drinking water treatment plants, this is usually achieved using flatbed aeration systems through which the water to be treated flows. Air is then introduced into the system by means of a blower.

[0005] Typically, ceramic aeration elements are used in shallow-bed aeration tanks. The main component of these elements is mullite, an aluminum silicate. Air is introduced into the ceramic aeration elements by a blower, and then passes through fine pores into the water. The air is mechanically and evenly distributed throughout the system via several distribution bars and ultimately dispersed into the water as fine bubbles by the connected ceramic aeration elements.

[0006] German patent application DE 10 2009 021 939 A1 discloses a device for aerating a liquid, in which several sintered ceramic tubes are designed as aeration bodies. The fine-pored structure of the sintered ceramic tubes allows the escape of fine air bubbles. The aeration bodies receive the air to be distributed via an air supply element, the air supply being assisted by a radial fan. The retaining element for attaching the aeration bodies is arranged on the air supply element outside the aeration bodies.

[0007] The ceramic aeration elements do create a very fine bubble pattern, but this is only possible with a very high differential pressure. Generating such high pressure, however, requires a significant amount of energy.

[0008] Especially when using an aeration system for the mechanical pre-deacidification of raw water, heavy deposits are to be expected, necessitating frequent cleaning. Due to the nature of the ceramic aeration element, it can only be cleaned chemically, which is a costly and time-consuming process. Disassembly and reassembly of the aeration elements is also extremely complex and often only feasible as a complete unit. Therefore, it is usually essential to implement redundant systems to ensure that one system can be cleaned while the other is in operation. Consequently, operating such a system incurs high costs.

[0009] DE 528 739 A discloses a device for distributing gases or air in liquids.

[0010] It describes a simple and particularly uniform method for distributing gases or air in liquids. Two nested, concentric tubes, the inner tube with air passage holes and the outer tube with air outlet slots, create fine gas bubbles through a tight fit and very fine spiral or circular grooves to control the air distribution.

[0011] From DE 35 13 370 A1 a water aeration pipe is known which is constructed from a rigid support pipe and a rubber hose located on it, and DE 42 21 356 A1 also relates to a device for aerating water.

[0012] German patent DE 102 18 073 A1 discloses an aerator for biological wastewater treatment.

[0013] The invention presents an aeration device that introduces sufficient oxygen into biologically treated wastewater to support the microbiological oxidation of organic pollutants and simultaneously promote the conversion of ammonium to nitrate. Thus, the technology contributes to improving ammonium removal in wastewater.

[0014] DE 43 37 091 A1 relates to a method for operating a water aeration system and to a device, in particular for carrying out the method. The method for aerating or gassing liquids, such as water, wastewater, and activated sludge, is improved with regard to its aeration performance by using predominantly or exclusively the upper part of the, for example, conical or cylindrical aeration elements for introducing air or oxygen bubbles. For this purpose, cylindrical or conical, or similarly elongated, aeration elements arranged horizontally are designed such that a much larger gas volume flow exits, in particular, from the upper side of the aerators than from the underside.

[0015] According to DE 10 2007 033 483 A1, a submersible aerator is described as an aeration device for wastewater treatment.

[0016] This document discusses submersible aerators used for ventilation in wastewater treatment plants, which are typically subject to membrane wear.

[0017] The document describes procedures for raising these aerators to the water surface for maintenance or replacement during ongoing plant operation without shutting down the plant.

[0018] DE 80 17 779 U1 discloses a gassing or ventilation pipe for introducing gaseous media into liquids, in particular for use in sewage treatment plants for the purification of wastewater.

[0019] Finally, EP 1493717 A1 discloses a method for flushing a biological wastewater treatment reactor, in which a section of the reactor is flushed with water and air at increased velocity. The flushing process is controlled solely by the air supply, thus eliminating the need for a separate valve control within the water supply.

[0020] The object of the invention is therefore to provide an aeration system which generates fine air bubbles for introduction into a liquid and which can be operated at a lower cost.

[0021] The problem is solved by the items with the features according to the independent patent claims. Further developments are specified in the dependent patent claims.

[0022] The problem is solved in particular by a double-pipe aeration element for the deacidification of water, which comprises at least one horizontally oriented inner pipe. According to the invention, the inner pipe has ventilation openings on its underside and an air inlet opening for introducing air into the inner pipe. Furthermore, the double-pipe aeration element has an outer pipe. The inner pipe is arranged inside the outer pipe. The outer pipe has ventilation openings on its upper side and at least one drainage opening on its underside.

[0023] An outer tube within the meaning of the invention is any hollow body whose wall thickness is small compared to its greatest extent.

[0024] An inner tube within the meaning of the invention is any hollow body whose wall thickness is small compared to its maximum dimension and which has a large dimension in one dimension compared to its dimensions in the other two dimensions. Preferably, the inner tube and the outer tube are tubular, i.e., hollow cylindrical.

[0025] The inner tube is horizontally aligned if its longest dimension is essentially horizontal.

[0026] The invention is suitable for generating very fine air bubbles. These can be used to deacidify water by stimulating the desorption of carbon dioxide, which is then removed from the water. Alternatively, such a fine bubble pattern can also be used, for example, to introduce oxygen into water, where it is absorbed. This is useful, for instance, in ponds stocked with fish.

[0027] A major advantage of the invention is the lower required differential pressure, i.e., the pressure exerted on the incoming air, which is necessary to allow the air to pass through the ventilation openings of the ventilation element. For this reason, the use of radial fans is possible, resulting in lower energy consumption and thus lower operating costs. The lower air resistance of the double-pipe ventilation element means that a higher air volume flow rate can be achieved with a double-pipe ventilation element according to the invention. Therefore, a larger volume of air can be introduced into the liquid.

[0028] Unlike simple pipes with various openings, this system allows for a uniform air pressure across the entire length of the outer pipe, resulting in consistent air infiltration into the water being treated, even with a lower differential pressure. This avoids pressure gradients within the outer pipe.

[0029] The drilled holes create larger openings in the pipes than are present in porous ceramic pipes. This reduces deposits and allows for longer maintenance and cleaning intervals.

[0030] The downward-facing holes in the inner pipe prevent water from entering. Furthermore, the drainage openings in the outer pipe prevent water from stagnating inside, which would increase the risk of bacterial growth. The specific arrangement of the holes ensures a continuous exchange of water entering the ventilation element, thus minimizing the risk of bacterial contamination.

[0031] No complex chemical cleaning is required; the double-pipe ventilation elements can be cleaned mechanically. This significantly reduces cleaning time compared to long-term chemical cleaning processes, and redundant ventilation element designs are generally no longer necessary. As a result, investment costs can be effectively reduced.

[0032] Since materials other than the typical ceramic materials of the state of the art can be used here, such as stainless steel or plastic or PVC, and since aggressive chemical cleaning is no longer necessary, the product lifespan of the ventilation elements is advantageously extended.

[0033] The inner and outer pipe ventilation openings are preferably designed as circular bores. Alternatively, they are slotted or rectangular in shape within the inner or outer pipe, respectively. In this case, the air inlet opening is larger than the inner and outer pipe ventilation openings.

[0034] Furthermore, the sum of the areas of the inner pipe ventilation openings is greater than or equal to the sum of the areas of the outer pipe ventilation openings. In this sense, the sum of the areas is the sum of the surface areas of the recesses in the outer and inner pipes, respectively. This results in sufficient pressure in the outer pipe and thus improved air distribution within the outer pipe along its entire length. Preferably, exactly one inner pipe is arranged inside the outer pipe, and the cross-sections of both the inner and outer pipes are preferably round, so that both are designed as tubes. Different arrangements of the inner pipe within the outer pipe are possible. Preferably, the inner and outer pipes are not arranged coaxially, but eccentrically. The axis of the inner pipe is preferably positioned below the axis of the outer pipe.

[0035] In an alternative embodiment, several inner tubes are arranged inside an outer tube. Preferably, the inner tubes are arranged in a single plane. The air from the multiple inner tubes is thus directed into the outer tube via the inner tube ventilation openings, and a uniform air cushion forms at the upper edge of the outer tube. The air then escapes evenly through outer tube ventilation openings on the top of the outer tube, forming fine air bubbles distributed across the entire top surface of the outer tube according to the pattern of the outer tube ventilation openings.

[0036] Alternatively, several inner tubes of different diameters can be arranged inside each other in multiple stages. This allows the differential pressure to be further reduced, resulting in additional energy savings and a finer bubble pattern.

[0037] In a suitable embodiment, the inner tube is arranged with one end face of the inner tube abutting an end face of the outer tube. The inner tube is fastened to the outer tube at this end face by a fastening element. For the purposes of the invention, an end face of the inner or outer tube is a surface that runs perpendicular to the greatest dimension of the inner or outer tube. The perpendicular of the end face thus runs parallel to the greatest dimension of the inner or outer tube.

[0038] The problem is also solved by a ventilation system which comprises at least one double-pipe ventilation element according to the invention for deacidifying water and further includes a blower, an air distribution bar and air supply nozzles. Each inner pipe can be connected to the air distribution bar via an air supply nozzle.

[0039] Preferably, the air distribution bar is designed perpendicular to the inner pipes. In an advantageous embodiment, the ventilation system is designed such that the double-pipe ventilation elements can be reversibly connected to the air distribution bar. Possible fastening methods include, for example, a screw connection, a plug-and-twist connection similar to a bayonet fitting, or a push-fit connection.

[0040] In a suitable design, each double-pipe ventilation element forms an individual connection to the air distribution bar and is designed to be reversibly mounted and dismounted from it. Thus, the double-pipe ventilation elements can be individually removed from the air distribution bar and also individually remounted.

[0041] The double-pipe ventilation element is designed as a combination of two pipes, with an inner pipe located inside an outer pipe. Air is drawn into the inner pipe, flows through it, and exits through ventilation openings on its underside, thus entering the outer pipe. An air cushion forms within the outer pipe, evenly distributed along its length, below the ventilation openings on its top surface. This air cushion creates a uniform air pressure throughout the entire length of the outer pipe, resulting in a consistent flow of air out of the outer pipe in the form of fine bubbles.The two pipes are arranged in a horizontal plane, so that the air escaping from the double-pipe aeration element is optimally distributed within a shallow water bath, thus ensuring effective removal of carbon dioxide from the water.

[0042] Water that penetrates the outer pipe is blown out again via drainage openings in the underside of the outer pipe.

[0043] Further details, features, and advantages of embodiments of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. These show: Fig. 1: a double pipe ventilation element from the side, Fig. 2: a double pipe ventilation element in a sectional view, Fig. 3: an outer tube in a perspective view, Fig. 4: an inner tube in a perspective view and Fig. 5: a section of a ventilation system.

[0044] In Fig. Figure 1 shows an embodiment of a double-pipe aeration element 1, which is arranged within a liquid to introduce air bubbles into this liquid. An inner pipe 2 is arranged within an outer pipe 3. Thus, both the lower inner pipe wall 2.1 and the upper inner pipe wall 2.2 are located within the outer pipe 3. The underside of the outer pipe 3 is formed by a lower outer pipe wall 3.1, and the upper side is formed by an upper outer pipe wall 3.2. The inner pipe 2 is preferably rotationally symmetrical about an inner pipe axis 4. An air supply nozzle 5 is arranged at one end face of the inner pipe 2, which is connected to the inner pipe 2 and through which air can flow into the inner pipe 2 and thus into the double-pipe aeration element 1. The air flowing into the inner pipe 2 can then escape from the inner pipe ventilation openings 6, which are arranged at the lower end of the inner pipe 2.The inner pipe ventilation openings 6 are preferably designed as through-openings in the lower inner pipe wall 2.1. The air exits the inner pipe 2 and then rises, distributing itself evenly along the upper edge of the outer pipe 3 below the upper outer pipe wall 3.2. The air cushion that forms in the outer pipe 3 is evenly distributed over the entire length of the outer pipe 3. Outer pipe ventilation openings 7 are arranged in the upper outer pipe wall 3.2 at the upper edge of the outer pipe 3. After reaching the upper outer pipe wall 3.2, the air passes through the outer pipe ventilation openings 7 and then rises further upwards in the form of fine air bubbles through the liquid surrounding the double-pipe ventilation element 1. The air pressure that builds up in the outer pipe 3 ensures, in particular, that the air bubbles exit evenly along the entire length of the outer pipe 3.To form particularly fine air bubbles, the ventilation openings 7 of the outer tube 3 are preferably even smaller than the ventilation openings 6 of the inner tube 2.

[0045] The lower inner pipe wall 2.1 is preferably arranged close to the lower outer pipe wall 3.1, thus the gap between them is narrow. The gap between the upper outer pipe wall 3.2 and the upper inner pipe wall 2.2, however, is wider, so that the path for the air bubbles from the inner pipe ventilation openings 6 to the outer pipe ventilation openings 7 corresponds approximately to the height of the outer pipe 3. This preferred arrangement promotes the formation of a uniform air cushion around the inner pipe 2 and thus the formation and release of fine air bubbles in a uniform distribution. In an advantageous embodiment, the inner pipe 2 and the outer pipe 3 are rigidly connected to each other at one end face by means of a fastening element 8. A sectional view of the double-pipe ventilation element 1 is shown in Fig. 2 shown. The section runs through the in Fig. 1 shown intersection points A-A9.

[0046] In a particularly suitable embodiment of a double-pipe ventilation element, the inner pipe 2 has one hundred circular openings with a diameter of 2.5 mm and the outer pipe 3 has two hundred circular openings with a diameter of 1.5 mm.

[0047] The double-pipe ventilation element 1 is shown in a sectional view in Fig. Figure 2 shows the inner tube 2 located inside the outer tube 3 at its lower end. The fastening element 8, which secures the inner tube 2 to the outer tube 3, is located in the center of the outer tube 3. It is clearly evident that the centers of the inner tube 2 and the outer tube 3 do not coincide. In this configuration, the center of the inner tube 2 is positioned below the center of the outer tube 3. The outer tube 3 is closed and sealed at one end by an outer tube closure element 10.

[0048] In the Fig. 3 and Fig. Figure 4 shows the inner pipe 2 and the outer pipe 3 of the double pipe ventilation element 1 individually in perspective views.

[0049] In Fig. Figure 3 shows a perspective view of the outer tube 3. An outer tube closure element 10 is arranged at one end of the outer tube, which closes the end face of the outer tube 3. Outer tube ventilation openings 7 are arranged on the top of the outer tube 3. In a preferred embodiment, the other end face of the outer tube 3 is open. After the double tube ventilation element is installed by a Fig. The inner pipe closure element 11 shown in Figure 4 also closes the end face of the outer pipe 3 opposite the outer pipe closure element 10.

[0050] The in Fig. Figure 4 shows the inner pipe 2 rotated to its position after installation in the double-pipe ventilation element 1 (not shown here), so that the lower side is visible. The lower inner pipe wall 2.1, which is located on the underside during operation of the double-pipe ventilation element 1, is thus shown at the top, so that the inner pipe ventilation openings 6 located in the lower inner pipe wall 2.1 point upwards. A fastening element 8 for attaching the inner pipe 2 to the outer pipe 3 is arranged on a closed end face of the inner pipe 2. The opposite end face of the inner pipe 2 is closed with an inner pipe closure element 11, on which fastening lugs 12 are arranged. After assembly, the outer pipe 3 lies within the fastening lugs 12, which thus act as a guide for the outer pipe 3.

[0051] In Fig. Figure 5 shows a ventilation system 13, which has a plurality of double-pipe ventilation elements 1. These double-pipe ventilation elements 1 are arranged parallel to each other and connected at one end face to the air distribution bar 14 via air supply nozzles 5. Air is conveyed into the air distribution bar 14 via air supply pipes 15 by means of a blower. This air then flows through the air supply nozzles 5 into the individual double-pipe ventilation elements 1. Fine air bubbles are then drawn out of the in Fig. 3 more clearly shown, ventilation openings 7 in the top of the outer pipes 3 of the double pipe ventilation elements 1 entered into the water.

[0052] Both ends of the outer tube are sealed. One end is hermetically sealed by the outer tube closure element 10, and the other end is hermetically sealed by the inner tube closure element 11. Thus, air entering the outer tube 3 can only escape to the outside through the outer tube ventilation openings 7, resulting in controlled bubble formation according to a specific pattern of these openings. In a preferred embodiment, the outer tube ventilation openings 7 are distributed uniformly along the entire length of the outer tube 3. Alternatively, the distribution and size of the openings can also vary along the length of the outer tube 3. A suitable pattern for the outer tube ventilation openings 7 is preferably determined by means of a corresponding flow calculation or by experimental tests.

[0053] In one embodiment, a deacidification plant has forty double-pipe ventilation elements 1 in a flatbed ventilation system 13 and is designed for the treatment of 50 m³ 3 Designed for a water flow rate of 20 m³ / h. 3 With a water volume per hour, an increase in pH value from 7.4 to 8.2 is achievable.

[0054] The double-pipe aeration element 1, designed to generate a uniform, fine-bubbled air distribution, serves for the mechanical deacidification of raw water. It consists of two main components: an outer pipe 3 and an inner pipe 3. Fig. The inner pipe 2 shown in section 4 can be assembled and disassembled in a sealing manner. The inner pipe 2 has a connection element with which it can be horizontally connected to the air distribution bar 14 of a flatbed ventilation system 13. Furthermore, the inner pipe 2 has downward-facing airflow channels in the sealed space. Fig.Figure 1 shows inner pipe ventilation openings 6 extending along the entire length of the inner pipe 2. The outer pipe 3 is fitted at one end with a cover as an outer pipe closure element 10 to ensure a tight seal and has upward-facing outer pipe ventilation openings 7 along its entire length for airflow. Furthermore, the outer pipe 3 has downward-facing drainage openings.

[0055] The special arrangement of the downward-facing (inner tube) and upward-facing (outer tube) holes 6, 7 allows the air to distribute evenly within the double tube. This creates a stable air cushion, resulting in a constant and uniform bubble pattern through the upward-facing holes 7 of the outer tube 3. Reference symbol list 1 double pipe ventilation element 2 inner tube 2.1 Lower inner pipe wall 2.2 Upper inner tube wall 3 Outer pipe 3.1 Lower outer pipe wall 3.2 Upper outer pipe wall 4 Inner tube axle 5 air inlet nozzles 6 Inner pipe ventilation opening, ventilation opening of the inner pipe 7. Outer pipe ventilation opening, ventilation opening of the outer pipe 8 Fastening element 9 intersection points AA 10 Outer pipe closure element 11 Inner tube closure element 12 Mounting lug 13 Ventilation system, flatbed ventilation system 14 air distribution bars 15 Air supply pipe

Claims

[1] Double-pipe aeration element (1) for deacidifying water, comprising at least one horizontally oriented inner pipe (2) with inner pipe ventilation openings (6) on the underside of the inner pipe (2) and an air inlet opening for introducing air into the inner pipe (2), wherein the double-pipe aeration element (1) further comprises an outer pipe (3) which has outer pipe ventilation openings (7) on the top side and at least one drainage opening on the underside, wherein the sum of the areas of the inner pipe ventilation openings (6) of the inner pipes (2) is greater than or equal to the sum of the areas of the outer pipe ventilation openings (7) of the outer pipe (3) and the inner pipe (2) is arranged inside the outer pipe (3) such that an air cushion distributed evenly over the length of the outer pipe (3) is formed below the outer pipe ventilation openings (7) on the top side of the outer pipe (3). [2] Double pipe ventilation element (1) according to claim 1, characterized by, that the cross-sections of the inner tube (2) and the outer tube (3) are round. [3] Double pipe ventilation element (1) according to claim 1 or 2, characterized by that several inner tubes (2) are arranged inside the outer tube (3). [4] Double pipe ventilation element (1) according to one of claims 1 to 3, characterized by that the inner tube (2) and the outer tube (3) are not arranged coaxially. [5] Double pipe ventilation element (1) according to one of claims 1 to 4, characterized by , that the inner tube (2) abuts an end face of the outer tube (3) and the inner tube (2) is designed to be fastened to the outer tube (3) at this end face by a fastening element (8). [6] Ventilation system (13) with at least one double-pipe ventilation element (1) according to one of claims 1 to 5 for deacidifying water, further comprising a blower, an air distribution bar (14) and air supply nozzles (5), wherein each inner pipe (2) can be connected to the air distribution bar (14) via an air supply nozzle (5). [7] Ventilation system (13) according to claim 6, characterized by , that the air distribution bar (14) is designed perpendicular to the inner tubes (2). [8] Ventilation system (13) according to one of claims 6 or 7, characterized by , that the double pipe ventilation elements (1) are designed to be reversibly connectable to the air distribution bar (14). [9] Ventilation system (13) according to claim 8, characterized by , that the double pipe ventilation elements (1) can be connected to the air distribution bar (14) via screw connections, plug-and-turn connections or plug connections.

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