Lateral channel compressor

Abstract

 In a lateral channel compressor with an impeller (12) which is arranged in a casing and which is supported so that it is rotatable around an axial rotational axis (4), said impeller comprising a plurality of impeller blades (20) which are arranged in a working area (2) which is formed by the casing, in view of enabling a complex lateral channel geometry with a high surface quality at low manufacturing costs, it is provided that the working area (2) comprises an undercut and the casing comprises a basic casing element (6), a cover (8) and an insert (10) in order to form the undercut.

Description

[0001] With a lateral channel compressor or gas ring compressor, a gas which is to be compressed is set in a helically shaped motion in at least one ring-type lateral channel using a rotating impeller driven by a drive aggregate, and is compressed by an intake into a pressure joint. The gas which is sucked on the intake is carried along due to the impeller which is rotating in the lateral channel, is set in the helically shaped motion in the circumferential direction and after nearly 360° is again expelled back over the pressure joints. The lateral channel compressor can be used as both a compressor and as a vacuum pump. The lateral channel compressor is very robust, thanks to its simple compression principle, and is preferably used for applications which require high volume flows of the gas. Particular advantages of the lateral channel compressor are that it is maintenance-free, has oil-free compression, low noise levels and a very long life cycle.

[0002] The degree of effectiveness of the lateral channel compressor depends crucially, among other things, on the geometry selected for the lateral channel, as well as on a defined flow guidance which is as free of turbulence as possible. With regard to a suitable flow in the lateral channel, the surface quality of the wall sections of the lateral channel is of significant importance. A high surface quality with a complex lateral channel geometry can frequently only be realised using special post-processing methods or complex manufacturing stages, which results in high manufacturing costs.

[0003] The object of the invention is to enable a complex lateral channel geometry with a high surface quality at low manufacturing costs.

[0004] The object is achieved according to the invention by means of a lateral channel compressor with the features described in claim 1. The lateral channel compressor comprises an impeller which is arranged in a casing and which is supported so that it is rotatable around an axial rotational axis, said impeller comprising a plurality of impeller blades which are arranged in a working area, the lateral channel, which is formed by the casing. The working area comprises a complex geometry and - when viewed in the axial direction - an undercut is formed. The casing comprises a basic casing element, a front cover and at least one insert in order to form the undercut.

[0005] Geometries with undercuts can usually, in terms of manufacturing technology, only be manufactured at a very high cost. The reason for this is that when the casting process is used with reusable casting moulds, it is not possible to form undercuts due to the necessary deformation procedure. Undercuts of this type must be incorporated using costly post-processing stages, such as machining methods, for example.

[0006] The special design of the lateral channel compressor with the insert achieves the particular advantage that an undercut is formed only by the insert, so that the remaining casing parts can be manufactured simply and cost-effectively. Overall, this enables a lateral channel compressor with a high degree of effectiveness at low manufacturing costs.

[0007] Here, it is appropriate that at least the basic casing element and the cover are diecast parts which can be manufactured cost-effectively and in large piece numbers due to the diecasting procedure. The option is also available of also forming the insert as a diecast part. Alternatively, this can also be a formed sheet part, for example, or a plastic injection moulded part.

[0008] With regard to the most simple design possible for the insert, this is formed as an insert ring which circulates at least to a large extent. The insert ring is here arranged so that it circulates around the axial rotational axis. Here, "circulating at least to a large extent" is understood in particular to mean that the insert ring circles around an angle range of approximately 330°, for example, and that it is only interrupted in the section between a pressure joint and an intake, and an interrupter in the lateral channel compressor, which is arranged therebetween. In the section between the suction inlet and the pressure outlet, the lateral channel is also interrupted.

[0009] According to an appropriate further development, the insert ring is formed as a circlip, and thus comprises a spring force or elasticity acting in the radial direction, so that it is clamped automatically without further means of attachment in the radial direction against the cover and/or the basic casing element. This measure also secures a defined radial position of the insert ring.

[0010] In order to also guarantee a defined position of the insert ring during operation, the insert is appropriately attached on the basic casing element and/or the cover. The attachment is completed here for example via welding, via attachment pins or attachment screws. The attachment is also, or alternatively, completed via a latch mechanism or a snap-on connection with the basic casing element and/or the cover. The option is also available of attaching the insert via a press fit. As a result of the attachment, the position of the insert is defined both in the radial and the axial direction in a reliable and immovable manner.

[0011] As an alternative or supplement to the assembly purposes, it is provided according to an appropriate further embodiment that the insert is clamped in particular between the basic casing element and the cover using a spring element which acts in the axial direction. This spring element is here in particular a metal band or a rubber ring. It is therefore preferably also formed as a sealing element which circulates at least to a large extent, and which is almost ring-shaped.

[0012] The basic casing element and the cover are usually separated along a separation level which is oriented vertically to the axial rotational axis. It is appropriate that the insert is arranged on only one side of the separation level, i.e. either on the side of the basic casing element or on the cover, so that only one of these two parts needs to be formed for retaining the insert.

[0013] With regard to a simple assembly, and at the same time, a precise position location of the axial position, it is appropriately provided that a boundary side of the insert lies in the separation level in its final assembled position, and that it therefore with this boundary side on the second part, preferably on the cover, supports itself or is pressed against the lid via the spring element.

[0014] Preferably, the insert comprises, when seen in cross-section, a base side and on the working area side a rib which extends in the radial direction, with two side flanks, each of which form a partial wall section of the working area. In order to enable the most even and turbulent-free flow guidance in the lateral channel as possible, the flanks of the rib align in each case with the adjacent partial wall sections of the working area, which are formed from the basic casing element or from the cover. The flanks of the rib thus run smoothly and free of edges and therefore homogeneously into the basic casing element or into the cover. The insert therefore comprises on both sides on the rib two surface sections of the working area. Overall, therefore, due to the insert, it is possible to create in a simple manner a dual-flow compartment lateral channel with two separate flow compartments which are separated via the insert at least in sections. Due to the insert, the two flow compartments are therefore separated spatially from each other between their radial end sections, so that in each respective flow compartment a limited and a defined flow is formed during operation, which has a positive effect on the overall degree of effectiveness.

[0015] Here, it is appropriately provided that the two flow compartments each comprise an elliptical cross-section geometry. With regard to a suitable flow guidance, a boundary is to a large extent created between the two flow compartments, i.e. their cross-section geometry is completely, or almost completely formed, with the exception of necessary or consciously selected gaps, by a tri-sectional casing and by a supporting ring for the impeller.

[0016] The present invention will now be described in greater detail below by way of exemplary embodiments which are explained with reference to the drawing. In the drawings, which are partially schematic:

Fig. 1

shows a section of a cross-sectional view of a dual-flow compartment lateral channel compressor in the area of the dual-flow compartment lateral channel, looking towards the direction of rotation of the impeller

Fig. 2

shows a perspective view of an insert which is formed as an insert ring

Fig. 3

shows an exploded view of the impeller, the insert ring and the basic casing element, wherein these three components are each shown cut in half, and

Fig. 4

shows a section, highly simplified, of a cross-sectional view of a lateral channel compressor in the area of an insert which is axially clamped via a spring element

[0017] In the Figures, the same parts, or parts which have the same function, are labelled with the same reference numerals.

[0018] The lateral channel compressor, a section of which is shown in Fig. 1, comprises a dual-flow compartment lateral channel 2 which forms a working area, with two flow compartments 2A, 2B with an elliptical cross-section which are arranged adjacent to each other in the axial direction 4. The lateral channel compressor comprises a multipart casing which comprises a basic casing element 6, a cover 8 and an insert 10 which is formed as an insert ring. The insert 10 comprises a rear side 10A and on the working area side a rib 10B with two side flanks, which extends in to the working area. The rib 10B separates the two flow compartments 2A, 2B in the radially outer partial section of the lateral channel 2 from each other and creates a boundary between them. The two flanks each form an inner wall partial section of each flow compartment 2A, 2B. The design of the insert 10 as an almost closed insert ring can be seen particularly clearly in the perspective view in Fig. 2.

[0019] In the housing, an impeller 12 is supported so that it is rotatable around a rotational axis which extends in the axial direction 4. The impeller 12 is driven by a drive shaft and a drive motor which are not shown here in greater detail. The impeller 12 extends in the radial direction 14 and comprises an impeller hub 16, to which a supporting ring 18 is attached, on which a plurality of impeller blades 20 are arranged in the circumferential direction or the rotational direction of the impeller 12. The supporting ring 18 protrudes with its underside in the axial direction 4 beyond the impeller hub 16 on both sides. It comprises a separating rib 22 which extends in the radial direction 14, which separates the two flow compartments 2A, 2B from each other and creates a boundary between them. Between the casing and the impeller 12, a gap is located, which is sealed via a sealing arrangement 24. This is affixed with screws 26 in the axial direction 4.

[0020] The elliptical cross-sectional area of the two flow compartments 2A, 2B is limited overall, and is formed by partial inner wall sections of the three casing parts 6, 8, 10, together with the separating rib 22. The partial inner wall sections thus form curved surfaces, in order to produce the elliptical cross-section contour. The curvatures of the partial inner wall sections are here selected and adapted to each other in such a manner that the wall sections run into each other in the most homogeneous and smooth manner possible. The individual wall sections are therefore essentially ananged so that they are aligned to each other.

[0021] The separating rib 22 extends in the radial direction 14 approximately over ¾ of the lateral channel height. In the radial direction 14, the separating rib 22 is extended by the rib 10B, leaving free a gap 28. The width of the gap is here of a sufficiently large dimension to prevent dust or fluff accumulating in this area.

[0022] In the exemplary embodiment according to Fig. 1, the insert 10 is inserted into a recess 30 in the basic casing element 6. Its left front or boundary side 10C falls into a separation level 32 between the basic casing element 6 and the cover 8. In the exemplary embodiment shown in Fig. 1, the insert 10 is pressed over the cover 8 against the boundary of the recess 30, so that the insert 10 is clamped overall between the two casing parts 6, 8 without additional auxiliary devices. This clamping attachment securely prevents the insert from being moved in the axial direction 4. At the same time, the insert 10 is formed as a type of circlip, as can be seen particularly clearly in Fig. 2, which comprises a spring force or elastic force which acts in the radial direction 14, so that through this spring force, the rear side 10A is pressed against the corresponding arrangement on the basic casing element 6. As a result, the position of the insert 10 is also affixed in the radial direction 14. For a clamping attachment in the axial direction, the option is available of leaving a small gap in the final assembled state between the cover 8 and the basic casing element 6 in the area of the boundary side 10C, thus guaranteeing that the cover 8 clamps the insert 10 with sufficient clamping force. The cover 8 is usually attached to the basic casing element using screws.
In the exemplary embodiment of Fig. 1, the insert 10 is retained solely by clamping in both the radial direction 14 and the axial direction 4. Additionally or as an alternative, the insert 10 is attached by welding, by screwing it on, or similar.

[0023] In order to manufacture the lateral channel compressor, the individual parts are produced as separate parts. The essential parts are the basic casing element 6, the cover 8, the insert 10 and the impeller 12, which - with the exception of the cover 8 - are shown in Fig. 3. Since in order to achieve the highest possible degree of effectiveness, the dimensional accuracy of the individual parts, together with a high surface quality of the lateral channel 2, are of significant importance, the parts are formed in a diecasting procedure as metal diecast parts. This procedure makes it possible to manufacture large piece numbers at low cost. At the same time, a high surface quality is achieved via the manufacturing procedure, without requiziuag costly post-processing stages. In addition, a very high dimensional accuracy is achievable with the diecasting procedure. The insert 10 can also be manufactured using alternative manufacturing procedures, or from alternative materials.

[0024] To assemble the lateral channel compressor, the insert 10 is first inserted in the axial direction 4 into the basic casing element 6 into the prespecified recess. The insert circulates completely around the lateral channel 2 and is only interrupted by an interrupter 34 shown in Fig. 3, which is arranged between a suction inlet and a pressure outlet not shown in greater detail here. Before the cover 8 is then screwed onto the basic casing element 6, the impeller 12 is placed onto the drive shaft which is not shown in greater detail here.

[0025] In the alternative embodiment according to Fig. 4, a spring element 36 is provided for positioning and affixing the insert 10 in the axial direction 4, which supports itself on the one hand on the basic casing element 6 and on a right boundary side 10D of the insert 10, and which presses the insert against the cover 8. The spring element 36 is here preferably formed as a circulating spring ring, such as a metal band or a rubber ring, and at the same time, takes on a sealing function.

[0026] In the exemplary embodiments shown in the Figures, the left boundary side 10C of the insert 10 aligns in each case with the separation level 32. As an alternative to this, it is also possible for the insert 10 to bridge the separation level 32, and for both casing parts 6, 8 to comprise a recess 30 for retaining the insert 10.

Claims

1. Lateral channel compressor with an impeller (12) which is arranged in a casing and which is supported so that it is rotatable around an axial rotational axis (4), said impeller comprising a plurality of impeller blades (20) which are arranged in a working area (2) which is formed by the casing; wherein the working area (2) comprises an undercut and the casing comprises a basic casing element (6), a cover (8) and an insert (10) in order to form the undercut.

2. Lateral channel compressor according to claim 1, in which at least the basic casing element (6) and the cover (8) are diecast parts.

3. Lateral channel compressor according to either one of claims 1 or 2, in which the insert (10) is formed as an insert ring which circulates at least to a large extent.

4. Lateral channel compressor according to claim 3, in which the insert ring takes the form of a circlip.

5. Lateral channel compressor according to any one of the above claims, in which the insert (10) is attached on the basic casing element (6) and/or on the cover (8).

6. Lateral channel compressor according to any one of the above claims, in which the insert (10) is clamped using a spring element (36).

7. Lateral channel compressor according to claim 6, in which the spring element (36) is at the same time formed as a circulating sealing element.

8. Lateral channel compressor according to any one of the above claims, in which the basic casing element (6) and the cover (8) are separated along a separation level (32) which is oriented vertically to the axial rotational axis (4), and the insert (10) is arranged only on one side of the separation level (32).

9. Lateral channel compressor according to claim 8, in which a boundary side (10C) of the insert (10) lies in the separation level (32).

10. Lateral channel compressor according to any one of the above claims, in which the insert (10) comprises, when seen in cross-section, a rear side (10A) and on the working area side a rib (10B) which extends in the radial direction, with two side flanks, each of which form a partial wall section of the working area (2).

11. Lateral channel compressor according to claim 10, in which the flanks of the rib (10B) align in each case with an adjacent partial wall section of the working area (2) which is formed from the basic casing element (6) and/or the cover (8).

12. Lateral channel compressor according to any one of the above claims, in which the working area (2) is formed as a dual-flow compartment lateral channel with two flow compartments (2A, 2B), and the flow compartments (2A, 2B) comprise an elliptical cross-section geometry, which is in particular formed almost completely by the casing and by a supporting ring (18) of the impeller (12).

Drawing