Fluid ring compressor

Abstract

A fluid ring compressor comprises a first single-acting compression stage having a first impeller eccentrically mounted in a housing and a second single-acting compression stage having a second impeller eccentrically mounted in a housing. The first compression stage and the second compression stage are separated from one another by a sealing gap. The sealing gap is arranged between a suction section of the first compression stage and a suction section of the second compression stage.

Claims

1. A fluid ring compressor having a first single-acting compression stage, which has a first impeller eccentrically mounted in a housing, and a second single-acting compression stage, which has a second impeller eccentrically mounted in the housing, wherein the first compression stage and the second compression stage are separated from one another by a sealing gap, characterized in that the sealing gap is arranged between a suction segment of the first compression stage and a suction segment of the second compression stage, the suction segment of the first compression stage extends across a first circumferential section of the compressor and the suction segment of the second compression stage extends across a second circumferential section of the compressor, wherein the suction segment of the first compression stage and the suction segment of the second compression stage adjoin each other and the first and second circumferential sections overlap one another.

2. The fluid ring compressor as claimed in claim 1, characterized in that the first compression stage has a first control disk, in that the second compression stage has a second control disk, wherein the first impeller and the second impeller are arranged between the first control disk and the second control disk.

3. The fluid ring compressor as claimed in claim 1, wherein the first impeller has chambers and the second impeller has chambers characterized in that a wall, which rotates with the impellers, is formed between the chambers of the first impeller and the chambers of the second impeller.

4. The fluid ring compressor as claimed in claim 3, characterized in that the sealing gap is arranged between a circumferential surface of the wall and an end surface of the housing.

5. The fluid ring compressor as claimed in claim 1, characterized in that the housing has a duct, which extends from an outlet side of the first compression stage to an inlet side of the second compression stage.

6. The fluid ring compressor as claimed in claim 1, wherein the first impeller and the second impeller are driven by a shaft characterized in that a third compression stage adjoins an outlet side of the second compression stage, wherein an impeller of the third compression stage is driven by means of said shaft.

7. The fluid ring compressor as claimed in claim 6, characterized in that the third compression stage is of double-acting design.

8. The fluid ring compressor as claimed in claim 6, characterized in that the impeller of the third compression stage is arranged between a first control disk and a second control disk and in that suction slots are formed in the first control disk and pressure slots are formed in the second control disk.

9. The fluid ring compressor as claimed in claim 6, characterized in that the impeller of the third compression stage has a balance piston, which closes off a pressure balancing chamber in an axial direction, wherein the pressure in the pressure balancing chamber is lower than on an outlet side of the third compression stage.

10. The fluid ring compressor as claimed in claim 1, characterized in that each impeller component is enclosed between two spacer sleeves in an axial direction.

11. The fluid ring compressor as claimed in claim 10, characterized in that one of the spacer sleeves is deformable.

12. The fluid ring compressor as claimed in claim 1, characterized in that the second compression stage is equipped with a feed for operating fluid, and in that the first compression stage is free from a feed line for operating fluid.

13. The fluid ring compressor as claimed in claim 1, and further comprising a third compression stage characterized in that the third compression stage is equipped with a feed for operating fluid.

14. The fluid ring compressor as claimed in claim 1, characterized in that it drives power of between 500 kW and 2 MW.

15. The fluid ring compressor as claimed in claim 2, wherein the first impeller has chambers and the second impeller has chambers characterized in that a wall, which rotates with the impellers, is formed between the chambers of the first impeller and the chambers of the second impeller.

16. The fluid ring compressor as claimed in claim 2, characterized in that the housing has a duct, which extends from an outlet side of the first compression stage to an inlet side of the second compression stage.

17. The fluid ring compressor as claimed in claim 3, characterized in that the housing has a duct, which extends from an outlet side of the first compression stage to an inlet side of the second compression stage.

18. The fluid ring compressor as claimed in claim 4, characterized in that the housing has a duct, which extends from an outlet side of the first compression stage to an inlet side of the second compression stage.

19. The fluid ring compressor as claimed in claim 2, wherein the first impeller and the second impeller are driven by a shaft characterized in that a third compression stage adjoins an outlet side of the second compression stage, wherein an impeller of the third compression stage is driven by means of said shaft.

20. The fluid ring compressor as claimed in claim 3, wherein the first impeller and the second impeller are driven by a shaft characterized in that a third compression stage adjoins an outlet side of the second compression stage, wherein an impeller of the third compression stage is driven by means of said shaft.

21. A fluid ring compressor having a first single-acting compression stage, which has a first impeller eccentrically mounted in a housing, and a second single-acting compression stage, which has a second impeller eccentrically mounted in the housing, the first impeller and the second impeller driven by a shaft, wherein the first compression stage and the second compression stage are separated from one another by a sealing gap, characterized in that the sealing gap is arranged between a suction segment of the first compression stage and a suction segment of the second compression stage and the suction segment of the first compression stage and the suction segment of the second compression stage adjoin each other and are arranged on a same side of the shaft.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is described by way of example below by means of advantageous embodiments with reference to the attached drawings, in which:

(2) FIG. 1 shows a perspective view of a compressor;

(3) FIG. 2 shows a partially broken-way view of the compressor from FIG. 1;

(4) FIG. 3 shows a section through the compressor from FIG. 1;

(5) FIG. 4 shows a component of the compressor from FIG. 1;

(6) FIG. 5 shows a section through an alternative embodiment of a compressor; and

(7) FIG. 6 shows an enlarged detail of FIG. 5.

DETAILED DESCRIPTION

(8) A fluid ring compressor shown in FIGS. 1 and 2 comprises a housing 14, which stands on the ground via four legs 15 and in which a shaft 16 is rotatably mounted. The shaft 16 extends over the entire length of the compressor. By means of the shaft 16, the total of three compression stages 17, 18, 19 of the compressor is driven jointly.

(9) A shaft journal 20 projecting from the housing 14 is used to connect a drive motor (not shown). The drive motor can have a power of 1 MW, for example. The opposite end of the shaft 16 is arranged within the housing 14.

(10) The compressor comprises an inlet opening 21, which extends through a stub provided with a flange. The gas is drawn into the compressor through the inlet opening 21. The compressor furthermore comprises a correspondingly designed outlet opening 22, through which the compressed gas is discharged again. Compression is performed by the three compression stages 17, 18, 19, through which the gas flows in succession.

(11) Secured on the shaft 16 in FIG. 4 is an integral component, on which an impeller 23 of the first compression stage 17 and an impeller 24 of the second compression stage 18 are formed. The two impellers 23, 24 are separated from one another by a central wall 26. In addition, an impeller 25 of the third compression stage 19 is connected to the shaft 16. The impellers 23, 24, 25 rotate with the shaft 16 in the housing 14.

(12) The sectional view in FIG. 3 shows that the impellers 23, 24 are mounted eccentrically in the housing 14. The clearance between the shaft 16 and the upper end of the internal space surrounding the impellers 23, 24 is smaller than the clearance between the shaft 16 and the lower end of the internal space. The internal space has a uniform contour, and therefore the clearance between the shaft 16 and the wall of the internal space is the same in every angular position for the first compression stage 17 and the second compression stage 18. Thus, the chambers of the first impeller 23 have their minimum volume in the same angular position as the chambers of the second impeller 24. A corresponding statement applies to the maximum volume and to the intermediate positions.

(13) The angular segment in which the volume of the chambers increases is referred to as the suction segment. The angular segment in which the volume of the chambers decreases is referred to as the pressure segment. In the sectional view in FIG. 3, the region situated below the shaft 16 belongs to the suction segment 271, 272 and the region situated above the shaft belongs to the pressure segment 281, 282. During one complete revolution, the impellers 23, 24 pass through precisely one suction segment 271, 272 and precisely one pressure segment 281, 282. Thus, the first compression stage 17 and the second compression stage 18 are single-acting. The compression process extends over more than 180.

(14) In the axial direction, the chambers of the impellers 23, 24 are each bounded by a control disk 29, 30. The control disks 29, 30 each have a suction slot in the suction segment 271, 272 and a pressure slot in the pressure segment 281, 282. The suction slot of control disk 29 is connected to the inlet opening 21 of the compressor. Gas drawn in through the inlet opening 21 passes through this suction slot into the chambers of impeller 23. As impeller 23 revolves, the volume of the chamber decreases and the compressed gas reemerges from the chambers of impeller 23 through the pressure slot of control disk 29. The compression process of the first compression stage 17 is thus complete. If the gas has been drawn in at an atmospheric pressure of 1 bar, the pressure at the outlet of the first compression stage can be between 2 bar and 3 bar, for example.

(15) The compressed gas is passed from the pressure slot of control disk 29 to the suction slot of control disk 30 through a duct 31 formed in the housing 14. The gas passes through the suction slot into the chambers of impeller 24. As impeller 24 revolves, the gas is further compressed. The gas reemerges from the second compression stage 18 through the pressure slot of control disk 30 at a pressure of between 4 bar and 6 bar, for example.

(16) The third impeller 25, which forms the third compression stage 19, is enclosed between a third control disk 32 and a fourth control disk 33. Control disk 32 comprises two suction slots offset by 180 relative to one another. Control disk 33 comprises two pressure slots offset by 180 relative to one another. The housing internal space surrounding the third impeller 25 is designed in such a way that it forms two suction segments and two pressure segments. In one complete revolution, impeller 25 thus passes through two suction segments and two pressure segments and therefore performs two compression processes. Each compression process extends over less than 180, and the third compression stage is double-acting. The suction slots in control disk 32 are positioned in such a way that they offer access to the suction segments. Correspondingly, the pressure slots in control disk 33 are positioned in such a way that they offer access to the pressure segments.

(17) From the outlet of the second compression stage 18, the gas is passed to the suction slots in control disk 32, thus allowing it to enter the chambers of impeller 25. After the compression process, the gas emerges from the third compression stage through the pressure slots of control disk 33 at a pressure of between 10 bar and 15 bar, for example. From there, the gas is passed out of the compressor through the outlet opening 22.

(18) Owing to the pressure difference between the first compression stage 17 and the second compression stage 18, a leakage flow can form between the chambers of the second impeller 24 and the chambers of the first impeller 23. The leakage flow passes through a sealing gap 28, which exists between the partition wall 26 of impellers 23, 24 and the surrounding housing. In order to keep down leakage flow, the radial clearance between the partition wall 26 and the housing is kept as small as possible, and a sealing ring is furthermore arranged in the sealing gap 28. However, it is not possible to completely avoid the leakage flow by these measures.

(19) A further contribution to reducing the leakage flow is made by the fact that the suction segments 271, 272 and the pressure segments 281, 282 of the first compression stage 17 and the second compression stage 18 are each arranged at the same angular position. As a result, the pressure difference between the first compression stage 17 and the second compression stage 18 is approximately the same in all angular positions and is of the order of a mere 2 bar to 3 bar. This small pressure difference likewise counteracts the formation of a high leakage flow.

(20) However, the corresponding angular position of the suction segments 271, 272 and pressure segments 281, 282 in the first two compression stages 17, 18 also has the effect that large forces act on the shaft 16 in the radial direction. These forces are absorbed by making the shaft 16 very massive. For example, the shaft can be made of steel and can have a diameter of 20 cm. This dimensioning has proven sufficient to prevent the shaft 16 bending excessively under the forces exerted by the impellers 23, 24.

(21) Owing to the pressure difference between the chambers of impeller 24 and the chambers of impeller 23, there is furthermore a large force acting in the axial direction on the shaft 16, said force being directed to the left in FIG. 3. These forces are absorbed by a main bearing 35 of large dimensions. The main bearing 35 is designed as a taper roller bearing, which can absorb not only the radial forces but also large axial forces. The second main bearing 34 absorbs primarily radial forces. The shaft 16 has no further support between the two main bearings 34, 35.

(22) In order to keep down the leakage flow within the respective compression stages 17, 18, 19, it is furthermore desired that the blades of the impellers 23, 24, 25 should move with the smallest possible clearance relative to the control disks 29, 30, 32, 33. This, in turn, presupposes that the impellers 23, 24, 25 are held with high accuracy in a particular position on the shaft 16. In the compressor, this is accomplished by arranging spacer sleeves 36, 37, 38 between the impellers and the shaft 16, said spacers defining a precise position in the radial direction.

(23) The spacer sleeves 36, 37, 38 furthermore define precise positions in the axial direction since they rest in the axial direction against suitable projections on the impellers 23, 24, 25. The unit comprising the spacer sleeves 36, 37, 38 and impellers 23, 24, 25 is clamped together in the axial direction by means of two shaft nuts 39, 40, with the result that all the elements have a precisely defined position.

(24) The spacer sleeves 36, 37, 38 are made of high-grade steel and hence from a different material than the shaft 16. When the compressor heats up, stresses may arise owing to the different thermal expansion coefficients. In order to absorb these in a controlled manner, spacer sleeve 38, which is arranged between the third impeller 25 and the pressure-side main bearing 35, is provided with internal grooves 41, which are shown in the enlarged illustration in FIG. 6. The grooves 41 form a weakening of spacer sleeve 38, with the result that deformation occurs due to thermal expansion in this region. This targeted deformation ensures that the axial position of the impellers 23, 24, 25 shifts only very slightly when the compressor heats up.

(25) In the alternative embodiment shown in FIG. 5, the hub 42 of impeller 25 is designed as a balance piston in order to reduce the axial pressure on the shaft 16. In the direction of the pressure side, the hub 42 is adjoined by a cylindrical cavity 43, which is sealed off with respect to the hub 42 by a sealing gap 44. The cavity 43 is connected by a line 45 to the suction side of the compressor, on which the pressure is substantially atmospheric pressure. Since the atmospheric pressure is passed to the outlet side of the third compression stage 19, the axial pressure is reduced and the shaft 16 is relieved of load.

(26) The second compression stage 18 and the third compression stage 19 are each connected to a feed line (not shown) for operating fluid, these being supplied by a liquid separator arranged on the pressure side of the compressor. The first compression stage 17 does not have a direct feed for operating fluid. Instead, the first compression stage is supplied with operating fluid via the sealing gap 28. The diameter of the sealing gap is chosen so that the desired flow of operating fluid is established.