EP0546335B1 - Device for introducing gas in fluids - Google Patents

Description

The invention relates to a device for gassing liquids according to the preamble of claim 1. Such a device is known from DE-C-507 294.

It has been proposed to achieve greater effectiveness, more cost-effective manufacture with less material and easier maintenance in such a gassing device in that the wall is designed as a support-free bladder, which is held only via a gas supply nozzle, except for a gas supply opening and the gas outlet openings. The gas distributor basically consists only of the bladder and has neither an inner nor an outer support structure. However, it has also been found here that the gas bubbles rise relatively quickly to the liquid level after exiting the bubble, as in the known horizontal tube aerator, and accordingly only a reduced fumigation of the liquid is effected.

In a ventilation device known from DE-OS 22 61 994, an air hose consisting of elastic material, connected at one end to an air supply line and closed at the other end, with an unperforated underside and with a plurality of air outlet openings, is provided, the air hose being on its longitudinal edges held by a support member and in the air hose is a membrane under the tension of an air cushion, which forms the lower boundary of an air duct connected to the air supply line. The two tube walls are connected to one another at the two longitudinal edges by a weld seam and each form a loop which encloses one of the two strand-shaped support members. The membrane, which is under the tension of an air cushion, is also welded to the two tube walls on its two side edges. The air hose is also supported on its two side edges by a sheet steel profile which covers the weld seams and is intended to prevent their peeling. The sheet steel profile is intended to increase the rigidity and weight of the air hose; it can also be provided on the underside of the air hose, the weight expediently being somewhat larger than the buoyancy of the hose filled with air. This known ventilation device is structurally complex and therefore expensive.

In a fumigation device known from DE-PS 34 10 267, a base body is provided which has at least one inlet for the gas. The membrane covers the base body and is attached to it. A device for limiting the stroke of the membrane is also attached to the base body. The inlet for the gas is passed through the base body as a passage opening. The limiting device consists of a connection which is fastened with one end to the membrane in the area of overlap of the passage opening and cooperates with its other end with a counterpart arranged in the area of the passage opening. Here too, therefore, many parts to be assembled are required, which make the fumigation device more expensive in terms of time and materials. In this gassing device, too, the gas emerges from the essentially horizontal membrane and rises to the liquid level relatively quickly.

It is therefore the object of the invention, while avoiding the disadvantages mentioned, to create a generic gassing device by means of which better ventilation of the liquid can be achieved with simple manufacture.

This object is achieved essentially with the features of claim 1.

The gas thus exits in the horizontal direction over the entire cylindrical outer surface of the membrane-like wall, so that the residence time of the gas bubbles in the liquid is increased and the ventilation effect is thereby improved compared to gas bubbles which emerge from an upwardly inclined or horizontally lying surface. The base provides the gas distributor with the necessary stability, while an increased downward directed liquid flow is achieved through the at least one liquid channel in the interior of the base. The reason for this phenomenon seems to be that the liquid around the membrane-like cylindrical wall has a higher concentration of gas bubbles than the liquid located further inside in the region of the liquid channel. As a result, the specific weight of the liquid around the gas distributor is less than that of the liquid in the region of the liquid duct, so that the liquid rises around the gas distributor while a downward flow occurs in the liquid duct of the gas distributor. This leads to increased liquid circulation and thus improved ventilation properties of the gas distributor. It was also found that the ascending bubble expands upwards as the gas flows out over the entire circumference of the wall. This is in contrast to gas distributors, in the center of which no liquid channel is formed. In the case of the latter gas distributors, the cross section of the rising bubble flow is reduced upwards. Also due to this circumstance, the liquid gassing is surprisingly improved with the device according to the invention.

In a particularly advantageous embodiment of the invention, the gas outlet openings are distributed essentially over the entire surface of the wall, preferably uniformly, in order to ensure a uniform supply of gas into the liquid.

A particularly simple and inexpensive manufacture and assembly of the invented gassing device is achieved in that the wall consists of a flexible cylindrical piece of hose, which is connected at its two axial ends to the preferably also cylindrical base body.

In a further development of this inventive concept, the at least one liquid channel is delimited by a hose element which leads through the chamber and is fastened to the base body. Here, the base body can have a very simple basic shape.

The hose element expediently has less flexibility than the wall. As a result, the wall expands when pressure is applied, while the hose element inside the gas distributor remains stiff and a reduction in the cross-section of the liquid channel is avoided.

However, it is also possible for the at least one liquid channel to be formed in one piece, for example as a bore in the base body.

In a preferred embodiment of the invention, a single liquid channel runs coaxially with the tube piece forming the wall. This results in a symmetrical flow profile of the downward directed liquid flow in the center of the gas distributor.

However, it is also possible for a plurality of liquid channels to be formed in the base body.

In a further preferred embodiment of the invention, in which the at least one liquid channel is not passed centrally through the base body, the gas supply channel is arranged coaxially with the base body.

According to a further feature of the invention, the effective opening cross section of the gas outlet openings is different in size in adaptation to the liquid pressure to be overcome by the gas emerging through the gas outlet openings. For example, in order to achieve a uniform gas outlet over the entire cylindrical membrane surface, the opening cross section of the gas outlet openings in the bubble wall decreases from bottom to top as the liquid pressure decreases from bottom to top depending on the vertical height of the bubble.

A uniform gas outlet can also be promoted in that the wall has different thicknesses in adaptation to the liquid pressure to be overcome by the gas emerging through the gas outlet openings. For example, the wall in the lower area has a smaller thickness than in the upper area, so that the gas passage through the gas outlet openings in the lower area of the wall is opposed to a lower flow resistance than in the upper wall area, so that the total pressure to be overcome by the escaping gas is approximately the same .

The wall can consist of a stretchable, for example rubber-elastic material, which bulges outwards under the pressurization required for the gassing and thereby enlarges the effective area of the gas distributor.

However, it is also possible for the wall to consist of a non-stretchable, for example textile material. In this case, the size and shape of the wall are fixed independently of the pressure above a minimum pressure of the gas.

On the other hand, it is also possible, if the textile material allows a certain stretch, to combine the properties of a stretchable with those of a non-stretchable material. This can be achieved in particular in that the wall consists of textile material or has a textile reinforcement insert or covering.

It is also within the scope of the invention if the gas outlet openings are made in the prestressed wall made of stretchable material. In this case, the gas outlet openings are closed without pressurizing the chamber, while they only open when the fumigation gas is at a minimum pressure. Within a certain pressure, the opening cross-section of the gas outlet openings is pressure-dependent and can be adjusted accordingly.

If a pressure-independent opening cross section of the gas outlet opening is desired, these are preferably introduced into the non-prestressed wall. They then have essentially the same opening cross section before and during the gas application regardless of the pressure.

Another feature of the invention is that the gas outlet openings block one from the inside out, i.e. have a radially increasing opening cross-section, i.e. are conical. This has the advantage that when the gas exits the wall, any dirt deposits are easily entrained from the gas outlet openings, thereby reducing the risk of blockages even of relatively small gas outlet openings. Such gas outlet openings are introduced into the wall from the outside, for example in the form of perforation by means of pinholes.

According to the invention, the gas is transported from the gas supply duct to the chamber with the wall by at least one connecting duct, which preferably runs radially in the base body, e.g. from the central gas supply duct to the outer surface of the base body.

A uniform pressurization of the entire wall is ensured in that an annular groove is formed on the outer surface of the base body, into which the connecting channel opens and which is covered by the wall.

In a further preferred embodiment of the invention, a tubular, flexible, membrane-like wall element is provided in the upper region of the base body, which is arranged offset radially inwards relative to the wall and forms the chamber with it.

The wall element can have a multiplicity of gas outlet openings. As a result, the liquid flow flowing downward inside the gas distributor can also be aerated.

For simple fastening of the gas distributor to the gas supply device, it is provided according to the invention that the gas supply channel has an internal thread with which the gas distributor can be screwed onto a pipe socket of the gas supply device provided with a corresponding external thread.

The gas supply channel is formed, for example, in a gas supply nozzle provided on the base body.

However, it is also possible for the gas distributor to be slipped onto a pipe socket of the gas supply device by means of the gas supply nozzle. Such a gas distributor can easily be replaced if it is defective. For safety, the gas supply connection can be fastened to the pipe connection by means of a clamp, so that even larger pressurizations can be handled.

In another embodiment, the gas distributor has a gas supply nozzle with a bead, which can be connected to a gas supply opening of the gas supply device. This also allows a relatively easy assembly and disassembly of the gas distributor.

In the gas supply channel and / or the pipe socket and / or the gas supply opening can also be used, for example, as a flap or Ball valve designed check valve can be arranged, which prevents the liquid from penetrating into the pipe socket or the piping system of the gas supply device when the pressure drops.

In order to counteract the buoyancy of the gassing device when the chamber is full, the invention also proposes that a ballast weight be arranged in the base body, in particular the chamber. The ballast weight can be formed as a hollow body made of rigid or flexible material, the interior of which is in flow connection with the liquid surrounding the gas distributor and / or can be filled with a liquid such as water, concrete, lead or the like as a ballast weight. However, the ballast weight can also be arranged outside the gas distributor. The base body itself can also be designed as a ballast weight.

Further objectives, features, advantages and possible uses of the present invention result from the following description of exemplary embodiments and the drawing.

Fig. 1

eine schematische Schnittdarstellung eines Gasverteilers gemäß einer ersten Ausführungsform der Er findung,

Fig. 2

eine Schnittdarstellung eines Gasverteilers nach einer zweiten Ausführungsform der Erfindung,

Fig. 3

eine Schnittdarstellung eines Gasverteilers nach einer dritten Ausführungsform der Erfindung entlang der Linie III - III in Fig. 4,

Fig. 4

eine Draufsicht auf den Gasverteiler nach Fig. 3,

Fig. 5

eine geschnittene Darstellung eines Gasverteilers nach einer vierten Ausführungsform der Erfindung gemäß der Linie V - V in Fig. 6,

Fig. 6

eine Draufsicht auf den Gasverteiler nach Fig. 5,

Fig. 7

eine Schnittdarstellung eines Gasverteilers nach einer fünften Ausführungsform der Erfindung entlang der Linie VII - VII in Fig. 8,

Fig. 8

eine Draufsicht auf den Gasverteiler gemäß Fig. 7,

Fig. 9

eine Seitenansicht einer erfindungsgemäßen Begasungsvorrichtung mit Darstellung der Befestigung an einer Gaszuführeinrichtung, und

Fig. 10

eine Seitenansicht einer weiteren Ausführungsform der Erfindung mit anders gearteter Befestigung an der Gaszufuhreinrichtung.

Show it:

Fig. 1

2 shows a schematic sectional illustration of a gas distributor according to a first embodiment of the invention,

Fig. 2

2 shows a sectional illustration of a gas distributor according to a second embodiment of the invention,

Fig. 3

3 shows a sectional illustration of a gas distributor according to a third embodiment of the invention along the line III-III in FIG. 4,

Fig. 4

3 shows a plan view of the gas distributor according to FIG. 3,

Fig. 5

6 shows a sectional illustration of a gas distributor according to a fourth embodiment of the invention along the line V - V in FIG. 6,

Fig. 6

5 shows a plan view of the gas distributor according to FIG. 5,

Fig. 7

8 shows a sectional illustration of a gas distributor according to a fifth embodiment of the invention along the line VII-VII in FIG. 8,

Fig. 8

7 shows a plan view of the gas distributor according to FIG. 7,

Fig. 9

a side view of a gassing device according to the invention showing the attachment to a gas supply device, and

Fig. 10

a side view of another embodiment of the invention with a different type of attachment to the gas supply device.

A device according to the invention for the gassing of liquids consists of a gas distributor 1 which is to be arranged under the liquid level and which can be connected to a gas supply device 2.

The gas distributor 1 shown in Fig. 1 consists of a base body 3, in which a chamber 4 and a gas supply channel 5 are formed. An internal thread is provided in the gas supply duct 5, so that the gas distributor 1 can be screwed onto a pipe socket of the gas supply device 2 provided with an external thread. The base body 3 is cylindrical and carries a cylindrical wall 6 made of flexible, membrane-like material, in which a multiplicity of gas outlet openings 7 are formed (cf. FIGS. 9 and 10). The wall 6 is fastened at its axial ends to the outside of the base body 3, for example with clips 8. If air is introduced into the chamber 4 through the gas supply duct 5, the wall 6 widens, as illustrated by the broken line. A liquid channel 9 extends essentially vertically through the base body 3 and is formed by a hose element 10 connected to the base body 3 at its upper and lower ends. The tubular element 10 can consist of solid or flexible material. The flexibility of the hose element 10 is less than the flexibility of the wall 6, so that the wall 6 inflates outwards when pressure is applied, while the hose element 10 remains stiff. When the gas distributor 1 is pressurized, air escapes through the gas outlet openings 7 in the wall 6 essentially in the horizontal direction. As a result, the gas bubbles remain in the liquid for a relatively long time. During operation, a liquid flow F directed downward is produced in the liquid channel 9, as indicated by the downward arrow in FIG. 1. The liquid flow F appears to be due to the fact that the liquid around the membrane-like cylindrical wall 6 has a higher concentration of gas bubbles than the liquid within the liquid channel 9. This makes it specific Weight of the gas-laden liquid around the gas distributor 1 on average less than that of the liquid in the inner liquid channel 9. This leads to an increase in the liquid around the gas distributor 1, while the liquid flows in the middle of the gas distributor 1 from top to bottom. This results in increased circulation and consequently better ventilation of the liquid. It has also been found that the ascending bubble flow increases upwards when the gas flows out over the entire circumference of the jacket 6. This phenomenon is in contrast to gas distributors, in the middle of which there is no liquid channel. With such gas distributors, the area of the rising gas bubbles decreases upwards. In this way too, better liquid ventilation is achieved with the device according to the invention.

The embodiment according to FIG. 2 differs from that shown in FIG. 1 essentially in that a plurality of liquid channels 9 are formed in the base body 3. The gas supply channel 5 in the embodiment according to FIG. 2 is also coaxial with the base body 3 and leads directly into the center of the chamber 4. A downward-directed liquid flow F is caused in each of the liquid channels 9.

In the embodiment according to FIGS. 3 and 4, the wall 6 lies essentially directly on the outside of the base body 3 when the gas distributor 1 is not pressurized. The chamber volume is then practically zero. However, a small recess can also be provided for the chamber 4. If the wall 6 is expanded outwards when pressure is applied, the chamber 4 is enlarged. The gas supply channel 5 is arranged coaxially of the base body 3 and connected to the chamber 4 via a plurality of radial connecting channels 11. The connection channels 11 are arranged in ribs 12 of the base body 3, which form a plurality of liquid channels 9 in a lower section of the base body 3. The air L enters the gas supply duct 5 from below, as illustrated by the arrow in FIG. 3, then radially outwards through the connecting ducts 11, as the arrows in FIG. 4 show, and then reaches the chamber 4, where the wall 6 widens outwards due to the pressure and the air exits through the gas outlet openings 7. Here, too, a downward directed liquid flow F is produced, which, as shown by the arrow in FIG. 3, flows through the plurality of liquid channels 9.

The embodiment shown in FIGS. 5 and 6 is similar to the embodiment according to FIGS. 3 and 4. In the embodiment according to FIGS. 5 and 6, however, an outer circumferential annular groove 13 covered by the wall 6 is formed in the base body 3, into which the connecting channels 11 open. The groove 13 ensures that the air or gas is guided over the entire circumference of the body 3 into the chamber 4 and to the inner surface of the wall 6. In contrast, in the embodiment according to FIGS. 3 and 4, the air or the gas, at least at the beginning, is introduced into the chamber 4 at only two points which correspond to the outer ends of the connecting channels 11. In this embodiment, the wall 6 should therefore have no gas outlet openings 7 in the area around the mouths of the connecting channels 11 into the chamber 4. Good gas distribution in chamber 4 is thereby achieved.

3 to 6, the upper region 3 'of the base body 3 consists of rigid material, in the embodiment according to FIGS. 7 and 8 this rigid section 3' of the base body 3 is replaced by a tubular, flexible, membrane-like wall element 14 , which has a plurality of gas passage openings. The lower end of the wall element 14 is fastened to the base body 3, while the upper end of the wall element 14 is held on a clamping element 15, for example via the clamps 8. The clamping element 15 can be a section of the base body 3 or be connected to it. If gas is now introduced into the chamber 4 via the connecting channels 11, the wall 6 will first expand outwards according to the dashed line. Thereafter, the wall element 14 will widen inwards, as illustrated by the dash-dotted line. By expanding the wall element 14 inwards into the liquid channel 9, the downward liquid flow in the liquid channel 9 is additionally increased. In the embodiment according to FIGS. 7 and 8, the groove 13 can also be formed in the base body 3.

The embodiments according to FIGS. 9 and 10 differ from the above. essentially by a different type of attachment of the gas distributor 1 to the gas supply device 2. The gas supply device 2 has a pipeline 16, from which one or more pipe sockets 17 branch off at a gas supply opening 18.

In the embodiment according to FIG. 9, a gas supply connection 19 is provided on the gas distributor 1, in which the gas supply channel 5 is formed. The gas supply nozzle 19 is on the Pipe socket 17 put over and can be fixed by means of a clamp 20. So that the gas distributor 1 is securely attached to the gas supply device 2. In the pipe socket 17 there is a check valve 21, which is designed as a ball valve and opens when the gas pressure is applied and closes when the pressure drops, so that no liquid can get into the gas distributor 1 and the gas supply device 2 via the gas outlet openings 7 before the opening of the gas supply channel 5.

The embodiment according to FIG. 10 differs from that shown in FIG. 9 essentially in that the gas supply connection 19 is designed as a bead 22 which can be buttoned into the gas supply opening 18 of the pipeline 16.

The direction of the liquid flow F is also made clear in the embodiments according to FIGS. 9 and 10 by the downward-pointing arrows.

Reference symbol list:

1

Gas distributor

2nd

Gas supply device

3rd

Basic body

3 '

upper section

4th

chamber

5

Gas supply duct

6

Wall

7

Gas outlets

8th

Parentheses

9

Liquid channel

10th

Hose element

11

Connecting channels

12th

Ribs

13

Groove

14

Wall element

15

Clamping element

16

Pipeline

17th

Pipe socket

18th

Gas supply opening

19th

Gas supply nozzle

20th

clamp

21

check valve

22

bead

23

inner thread

F

Liquid flow

L

Airflow

Claims (30)

1. Device for gassing liquids, in particular for the aeration of waste water, by means of a gas distributor (1) which can be arranged below the surface of the liquid and can be connected to a gas-feed apparatus (2), which distributor has at least one membrane-type wall (6) made from flexible material with a plurality of gas-outlet openings (7) and a basic body (3) around which the wall (6) is arranged essentially cylindrically and defines a chamber (4) in the basic body (3) which is connected to at least one gas-feed duct (5), characterized in that the wall (6) has an essentially vertically running central axis and the chamber (4) encloses at least one liquid duct (9) passing essentially vertically through the basic body (3).
2. Device according to claim 1, characterized in that the gas-outlet openings (7) are essentially distributed over the whole wall (6).
3. Device according to claim 1 or 2, characterized in that the wall (6) consists of a flexible cylindrical hose section which is connected at its two axial ends to the preferably likewise cylindrical basic body (3).
4. Device according to one of claims 1 to 3, characterized in that the at least one liquid duct (9) is defined by a hose element (10) passing through the chamber (4) and secured to the basic body (3).
5. Device according to claim 4, characterized in that the hose element (10) displays a lesser flexibility than the wall (6).
6. Device according to one of claims 1 to 3, characterized in that the at least one liquid duct (9) is formed in one piece, e.g. as a bore, in the basic body (3).
7. Device according to one of claims 3 to 6, characterized in that a single liquid duct (9) runs coaxially with the hose section forming the wall (6).
8. Device according to one of claims 1 to 6, characterized in that several liquid ducts (9) are formed in the basic body (3).
9. Device according to one of claims 1 to 6, in which the at least one liquid duct (9) is not guided centrally through the basic body (3), characterized in that the gas-feed duct (5) is arranged coaxial with the basic body (3).
10. Device according to one of claims 1 to 9, characterized in that the effective opening cross-section of the gas-outlet openings (7) is of a size which varies to match the liquid pressure to be overcome by the gas emerging from the gas-outlet openings (7).
11. Device according to one of claims 1 to 10, characterized in that the wall (6) is of a thickness which varies to match the liquid pressure to be overcome by the gas emerging from the gas-outlet openings (7).
12. Device according to one of claims 1 to 11, characterized in that the wall (6) consists of a stretchable. e.g. rubber-elastic, material.
13. Device according to one of claims 1 to 11, characterized in that the wall (6) consists of a non-stretchable material.
14. Device according to one of claims 1 to 13, characterized int that the wall (6) consists of a textile material or has a textile reinforcing insert or covering.
15. Device according to one of claims 1 to 12 and 14, characterized in that the gas-outlet openings (7) are incorporated into the pre-stressed wall (6) made from stretchable material.
16. Device according to one of claims 1 to 14, characterized in that the gas-outlet openings (7) are incorporated into the non-pre-stressed wall (6).
17. Device according to one of claims 1 to 16, characterized in that the gas-outlet openings (7) have an opening cross-section which increases from the inside outwards.
18. Device according to one of claims 1 to 17, characterized in that at least one connection duct (11) which connects the gas-feed duct (5) to the chamber (4) is formed in the basic body (3).
19. Device according to claim 18, characterized in that the at least one connection duct (11) runs radially in the basic body (3), e.g. from the central gas-feed duct (5) to the outer surface of the basic body (3).
20. Device according to claim 18 or 19, characterized in that an annular groove (13), into which the at least one connection duct (11) opens and which is covered by the wall (6), is formed on the outer surface of the basic body (3).
21. Device according to one of claims 1 to 20, characterized in that a tubular, flexible, membrane-like wall element (14), which is arranged radially offset inwards relative to the wall (6) and forms the chamber (4) with the latter, is provided in the upper area of the basic body (3).
22. Device according to claim 21, characterized in that a plurality of gas-outlet openings is formed in the wall element (14).
23. Device according to one of claims 1 to 22, characterized in that the gas-feed duct (5) has an inner thread (23).
24. Device according to one of claims 1 to 23, characterized in that the gas-feed duct (5) is formed in a gas-feed nozzle (19) provided at the basic body (3).
25. Device according to one of claims 1 to 24, characterized in that the gas distributor (1) is fitted by means of the gas-feed connection (19) onto a pipe socket (17) of the gas-feed apparatus (2).
26. Device according to one of claims 1 to 24, characterized in that the gas distributor (1) has a gas-feed connection (19) with bead (22) which can be pushed into a gas-supply opening (18) of the gas-feed apparatus (2).
27. Device according to one of claims 1 to 26, characterized in that a non-return valve (21) is arranged in the gas-feed duct (5) and/or in the pipe nozzle (17) and/or in the gas-supply opening (18) or in the vicinity thereof.
28. Device according to one of claims 1 to 27, characterized in that a ballast weight is arranged in the basic body (3).
29. Device according to claim 28, characterized in that the ballast weight is developed as a hollow article made from rigid or flexible material, the inside of which is in flow connection with the liquid surrounding the gas distributor (1) and/or can be filled with a liquid such as water, concrete, lead or the like.
30. Device according to one of claims 1 to 29, characterized in that the basic body (3) is developed as a ballast weight.

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