EP1477681B1 - Liquid ring gas pump - Google Patents

Abstract

The fluid ring gas pump has a housing section (5) to take one or two working zones (16), as a radial shrouding around them. Each zone has a vane wheel (1) on an eccentric mounting. Two further housing sections (4) flank the first housing section and the pump on both sides, with channels or chambers for the inflow and outflow of the carrier gas. The working zones are defined axially on both sides by control disks (2,3). The first housing section is a one-piece unit, with a connecting channel (7) to link the side housing sections together. The openings at the center housing section are set so that the side housing sections are of an identical design.

Description

The invention relates to a liquid ring gas pump having a first housing part, which encloses two working spaces radially, in each of which an eccentrically rotatably mounted impeller is arranged, with second and third housing parts, which complete the first housing part and the pump on both sides and channels or chambers for supply and Having discharge of the delivered gas, with at least one of second leading to the third housing part connecting channel and with the working spaces in the axial direction limiting control discs.

In liquid ring gas pumps, an impeller rotates within an eccentrically rotating fluid ring. During the circulation, the liquid ring more or less immersed in the cells formed between the wings of the impeller. As a result, the free volume in the impeller cells is alternately increased and decreased. In the circulation area in which the cell volume increases, the suction opening, through which the gas to be delivered is sucked into the cells, is located in the front side in a control disk. In the end region of that circulation part, in which the compression takes place, there is the pressure opening through which the compressed gas is ejected into the pressure chamber of the pump.

Liquid ring gas pumps are used both as a vacuum pump, where the delivery gas is compressed from a negative pressure to about atmospheric pressure, as well as a compressor in which the delivery gas is compressed from atmospheric to an overpressure. Liquid ring gas pumps are available as single-stage and multi-stage versions. Single-stage liquid ring gas pumps can be used as a vacuum pump in the upper rough vacuum or as a compressor due to the lower compression ratio. Multi-stage machines have their preferred use as a vacuum pump in the lower pressure range of the vacuum.

The work spaces in which the impeller rotates and the liquid ring is formed, are limited axially on one side or on both sides by a control disk. In multi-stage liquid ring pumps these work spaces with impeller and control discs are arranged axially in a corresponding number one behind the other.

Traditionally, a liquid ring gas pump (cf, for example, DE 27 14 475 A) consists of a multiplicity of components which are arranged in the axial direction against each other during pump assembly. The bearing surfaces of the individual components are simultaneously sealing surfaces of the machine from the pump interior to the environment. Axially outward close to the control discs, the outer housing, in which channels or chambers for the guidance of the gas and liquid flows are included. Also between the control discs and the outer housings are again sealed surfaces.

Such a conventional liquid ring gas pump has in two-stage design seven axial sealing surfaces (DE 27 14 475). Consequently, the assembly is expensive and the construction expensive and also has the disadvantage of a variety of surfaces to be sealed, in particular a greater risk of early leaking in operation.

In two-stage liquid ring compressors, a widely used construction is provided with a diagonal connection pipe, with which a part of the gas to be compressed and the working fluid is directed from the first stage pressure port to the second stage suction port (DE-PS 870 004). Since this connecting tube is placed on both sides of the housing neck, here are two more sealing surfaces available. The disadvantages of these classic constructions are the large number of individual parts with correspondingly high production costs for machining the many surfaces and the many surfaces to be sealed between the pump components.

Already known are various approaches to simplify pump parts or merge several pump components and so reduce the number of parts of the liquid ring gas pumps. For example, it is known to perform a control disc with the center body as a component (drawing Travaini pumps TRHC 40-60). It is also known a single-stage liquid ring compressor, in which the division of the suction gas flows and the merger of the pressure-side gas flows is not outside the compressor by so-called bottlenecks, but the gas flow is connected only in one side of the housing and the division of the other side of the housing by straight tubes takes place (EP 0 584 106 B1). It is also known to accommodate all axial flow channels in the middle housing part (DE 197 58 340 A1). The disadvantage of this embodiment is that it is only applicable to single-stage liquid ring gas pumps.

The object of the invention is to provide a liquid ring gas pump of the type mentioned, in which the number of items and in particular the number of sealing surfaces is greatly reduced to the outside.

The solution according to the invention is that the first housing part is formed in one piece, and has an integrally formed with the first housing part intermediate wall for receiving inner control discs between the two working spaces. In particular, the intermediate wall may comprise at least one channel for passing the conveyed gas .

The invention is applicable to two-stage liquid ring gas pumps.

In an advantageous embodiment, the first housing part has not more than two surfaces connected to the work spaces, with which it adjoins other housing parts or other attachments.

The construction of the pump is further simplified if the first housing part has connections for emptying and / or emptying, cavitation protection and suction-side ventilation.

The housing parts may be formed in an advantageous embodiment as a cast construction. In another advantageous embodiment, the housing parts are designed as a welded construction.

A particularly simple assembly is possible if the first housing part has fastening elements for axial clamping with the second and third housing parts.

• zweifach den klassischen rohrartigen Mittelkörper,
• das Verbindungsrohr, das die Strömung von der ersten zur zweiten Stufe leitet,
• die Halterung der mittleren, jetzt besonders einfach als ebene Scheiben zu gestaltenden Steuerscheiben,
• die äußeren Steuerscheiben können zwischen erstem Gehäuse und dem zweiten bzw. dritten Gehäuse so verspannt werden, dass keine zweifache äußere Abdichtung erforderlich ist;
• die Gesamtzahl der Dichtflächen wird von maximal neun auf jetzt nur noch zwei Dichtflächen reduziert. Bei der herkömmlichen zweistufigen Pumpe gab es sieben Dichtflächen zwischen den Steuerscheiben, Mittelkörpern und äußeren Gehäusen sowie zwei zwischen den Gehäusen und dem Verbindungsrohr.

The liquid ring gas pump according to the invention comprises in a single component, namely the first housing part according to the invention, the following previous components or functions:

• twice the classic tubular centerbody,
• the connecting tube, which conducts the flow from the first to the second stage,
• the holder of the middle, now particularly easy to be designed as a flat slices control discs,
• the outer control discs can be clamped between the first housing and the second or third housing so that no two-fold outer seal is required;
• The total number of sealing surfaces is reduced from a maximum of nine to only two sealing surfaces. In the conventional two-stage pump, there were seven sealing surfaces between the control disks, center bodies and outer housings and two between the housings and the connecting pipe.

The construction according to the invention is characterized by a low number of components and few sealing surfaces to the outside. This results in significant advantages in the manufacturing and assembly process as well as in the reliability of the novel liquid ring gas pump. A particular advantage is also that the second and third housing parts can be identical, which also reduces the manufacturing cost and storage costs for spare parts.

Figur 1

im Querschnitt eine konventionelle Flüssigkeitsringgaspumpe;

Figur 2

im Querschnitt eine erste Ausführungsform einer erfindungsgemäßen Flüssigkeitsringgaspumpe; und

The invention will be described below with reference to advantageous embodiments with reference to the accompanying drawings, for example. Show it:

FIG. 1

in cross section a conventional liquid ring gas pump;

FIG. 2

in cross section a first embodiment of a liquid ring gas pump according to the invention; and

FIG. 1 shows in cross section a conventional liquid ring gas pump. In workrooms A are eccentrically mounted on a shaft B impellers C. The work spaces A are partially with a liquid, in particular water filled, so that the cells between the wings of the impellers due to the liquid ring enlarge and reduce, whereby the pumping action is achieved. At the end faces of the impellers C are control discs D, in the embodiment of Figure 1 so four such control discs. Housing parts E limit the work spaces in the radial direction to the outside. At the two ends there are still housing parts F, which have the required channels or chambers for the supply and discharge of the gas to be pumped. As can be clearly seen in FIG. 1, a great many components are assembled successively in the axial direction, wherein a seal must be provided at the connecting points in each case to the outside.

The two-stage pump according to the invention, which is shown in Figure 2, also has two impellers 1, which are mounted on a shaft 11 and rotate in the eccentric working spaces 16. At the outer end faces of the impellers 1 are control discs 2; In the middle between the impellers 1 are control discs 3, wherein the control discs are provided with suitable openings through which enters the gas to be pumped into the working spaces 16 and exits. In Fig. 2, there is shown a connecting passage 13 connecting the suction port 14 of the left (second) stage with the pressure port 15 of the right (first) stage, whereby a partial flow of the conveying gas from the right (first) stage to the left (second) stage is directed. The respective other opening of the middle control discs 3 is covered by the middle wall 8 and thus functionless. This middle wall 8 is part of a first housing part 5, which surrounds the working spaces 16. This first Housing part 5 has a further connecting channel 7 for the gas flows within the pump. In the two-stage pump, a second partial flow of the delivery gas is passed from the pressure port 17 of the right (first) stage to the suction port 18 of the left (second) stage.

As can be seen, the outer wall 6, which limits the working space 16, the intermediate wall 8 and the connecting channel 7 are integrally formed. Further components are the left and right of the first housing part 1 arranged second and third housing parts 4, which may be identical. The only sealing surfaces to the outside are the sealing surfaces between the first housing and the second housing 4. These sealing surfaces are designated 9. With 19 screws are designated by which the housing parts 1, 4 are fastened together.

Claims (7)

1. Liquid ring pump having a first housing part (5) which encloses two working spaces (16) radially, in which in each case there is arranged an eccentrically rotatably mounted impeller (1), having second and third housing parts (4), which seal off the first housing part (5) and the pump on both sides and have ducts or chambers for the supply and discharge of the gas conveyed, having at least one connecting duct (7) leading from the second to the third housing part and having control discs (2, 3) that bound the working spaces (16) in the axial direction, characterized in that the first housing part (5) is formed in one piece, and comprises an intermediate wall (8) which is formed in one piece with the first housing part between the two stages, for accommodating the inner control discs (3).
2. Liquid ring pump according to Claim 1, characterized in that the intermediate wall (8) has at least one duct (13) to lead the conveyed gas through.
3. Liquid ring pump according to Claim 1 or 2, characterized in that the first housing part has no more than two surfaces (9) which are connected to the working spaces (16) and with which it adjoins other housing parts or other fitted parts.
4. Liquid ring pump according to one of Claims 1 to 3 characterized in that the first housing part (5) has connections for emptying and/or emptying dirt (10), for cavitation prevention (11) and for venting (12) on the suction side.
5. Liquid ring pump according to one of Claims 1 to 4, characterized in that the housing parts (4, 5) are formed as a cast construction.
6. Liquid ring pump according to one of Claims 1 to 4, characterized in that the housing parts (4, 5) are formed as a welded construction.
7. Liquid ring pump according to one of Claims 1 to 6, characterized in that the first housing part (5) has fixing elements (19) to be clamped axially with the second and third housing parts (4).

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