Screw compressor having rotors mounted on one side

Abstract

The invention relates to a screw compressor for compressing a medium, having a drive unit which has a drive, and having a compressor unit which has two mutually engaging rotors with screw profiles, which are complementary to one another, and a compressor housing having an inlet and an outlet. The rotors are coupled to the drive unit via a shaft in each case. The shafts are only mounted on the drive side of the rotors. The rotors are mounted only on one side relative to their axial direction and are not mounted on the side which faces axially away from the drive. The invention furthermore relates to a screw compressor arrangement with screw compressors which are fluidically connected in series.

Claims

1. A screw compressor assembly for compressing a fluid medium comprising: a drive unit configured to drive a first shaft and a second shaft, the first shaft defining a first axis of rotation and the second shaft defining a second axis of rotation, the first axis of rotation parallel to the second axis of rotation, the first shaft having a first end and a second end, the first end configured to be directly driven by the drive unit; a compressor unit including a compressor housing, a main rotor and a subsidiary rotor, the main rotor and the subsidiary rotor having mutually engaging screw profiles and positioned parallel from each other, the first shaft rotatably driving the main rotor around the first axis of rotation and the second shaft rotatably driving the subsidiary rotor around the second axis of rotation; and a bearing unit disposed between the drive unit and the compressor unit, the bearing unit housing the first shaft and the second shaft and including a pair of gearwheels, each one of the pair of gearwheels respectively coupled to the first shaft and the second shaft and configured to synchronously drive the second shaft with respect to the first shaft; wherein the main rotor and the subsidiary rotor are respectively mounted to the first shaft and the second shaft on a first axial direction, the first axial direction facing the drive unit.

2. The screw compressor assembly of claim 1, wherein the bearing unit includes a first bearing, a second bearing, a third bearing, and a fourth bearing, the first bearing and the second bearing supporting the first shaft and the third bearing and the fourth bearing supporting the second shaft.

3. The screw compressor assembly of claim 2, wherein the second shaft has a first end and a second end, where the third bearing is configured to support the first end of the second shaft, and the second end of the second shaft is configured to drive the subsidiary rotor.

4. The screw compressor assembly of claim 1, wherein the drive unit, the bearing unit, and the compressor unit are modular, separate units from one another.

5. The screw compressor assembly of claim 1, wherein the compressor unit is housed within a compressor unit housing, the compressor unit housing including a housing lid covering the main rotor and the subsidiary rotor from a second axial direction, the second axial direction facing away from the drive unit.

6. The screw compressor assembly of claim 5, wherein the compressor housing includes an inlet and an outlet, the inlet disposed on the compressor housing transversely from the first axis of rotation and the second axis of rotation and the outlet disposed on the housing lid, axially from the first axis of rotation and the second axis of rotation.

7. The screw compressor assembly of claim 5, wherein the unit housing includes a cooling jacket having a plurality of cooling channels, the cooling channels carrying a cooling agent configured to cool a pressurized medium being delivered by the compressor unit.

8. The screw compressor assembly of claim 5, wherein the cooling jacket covers the housing lid.

9. The screw compressor assembly of claim 1, wherein the main rotor and the subsidiary rotor respectively have a length to diameter ratio between 0.2 and 1.2.

10. A screw compressor assembly for compressing a fluid medium comprising: a drive unit configured to drive a first shaft and a second shaft, the first shaft defining a first axis of rotation and the second shaft defining a second axis of rotation, the first axis of rotation parallel to the second axis of rotation, the first shaft configured to be directly driven by the drive unit; a compressor unit including a compressor housing, a main rotor and a subsidiary rotor, the first shaft rotatably driving the main rotor around the first axis of rotation and the second shaft rotatably driving the subsidiary rotor around the second axis of rotation; a first gearwheel and a second gearwheel, the first gearwheel coupled to the first shaft and the second gearwheel coupled to the second shaft; and a bearing unit disposed between the drive unit and the compressor unit, the bearing unit housing the first shaft, the second shaft, the first gearwheel and the second gearwheel, the bearing including a first bearing, a second bearing, a third bearing, and a fourth bearing, the first bearing and the second bearing supporting the first shaft and the third bearing and the fourth bearing supporting the second shaft; wherein the second gearwheel and the first gearwheel are configured to synchronously drive the second shaft with respect to the first shaft.

11. The screw compressor assembly of claim 10, wherein the second shaft has a first end and a second end, where the third bearing is configured to support the first end of the second shaft, and the second end of the second shaft is configured to drive the subsidiary rotor.

12. The screw compressor assembly of claim 10, wherein the drive unit, the bearing unit, and the compressor unit are modular, separate units from one another.

13. The screw compressor assembly of claim 10, wherein the main rotor and the subsidiary rotor are respectively mounted to the first shaft and the second shaft on a first axial direction, the first axial direction facing the drive unit.

14. The screw compressor assembly of claim 10, wherein the compressor unit is housed within a compressor unit housing, the compressor unit housing including a housing lid covering the main rotor and the subsidiary rotor from a second axial direction, the second axial direction facing away from the drive unit.

15. The screw compressor assembly of claim 14, wherein the compressor housing includes an inlet and an outlet, the inlet disposed on the compressor housing transversely from the first axis of rotation and the second axis of rotation and the outlet disposed on the housing lid, axially from the first axis of rotation and the second axis of rotation.

16. The screw compressor assembly of claim 14, wherein the unit housing includes a cooling jacket having a plurality of cooling channels, the cooling channels carrying a cooling agent configured to cool a pressurized medium being delivered by the compressor unit.

17. The screw compressor assembly of claim 14, wherein the cooling jacket covers the housing lid.

18. The screw compressor assembly of claim 10, wherein the main rotor and the subsidiary rotor respectively have a length to diameter ratio between 0.2 and 1.2.

Description

(1) FIG. 1 shows a perspective overall view of a screw compressor according to the invention;

(2) FIG. 2 shows a cross-sectional view of the screw compressor according to FIG. 1.

(3) FIG. 1 shows an embodiment, by way of example, of a screw compressor according to the invention in a simplified perspective view from the outside, while the details in FIG. 2 are depicted in a cross-sectional view.

(4) The screw compressor has a drive unit 01, a bearing unit 02 functionally linked to this, and a compressor unit 03. The bearing unit 02 is situated, when viewed in the axial direction, between the drive unit 01 and the compressor unit 03. The drive unit 01, the bearing unit 02 and the compressor unit 03 are preferably constructed modularly so that they can be put together in a way which is adapted to the relevant application. In particular, however, the drive unit 01 and the bearing unit 02 may also be configured as a structural unit.

(5) The drive unit 01 has a drive housing 05, in which an electrical direct drive with an internally situated drive rotor 06 and an externally situated drive stator 07 are arranged. Furthermore, an external drive cooling jacket 08 is provided with cooling channels through which a cooling agent flows. The drive rotor 06 is connected to a first shaft 10 in order to cause the shaft 10 to rotate. The first shaft 10 is mounted in a first bearing, for example a spindle bearing 11, which is situated axially proximate to the drive rotor 06, and in a second bearing, for example a spindle bearing 12, which is situated in the bearing unit 02.

(6) The drive unit 01 furthermore comprises a second shaft 14 which runs axially parallel to the first shaft 10 and is mounted in a third bearing, for example a spindle bearing 15, in the drive unit 01 and in a fourth bearing, for example a spindle bearing 16, situated in the bearing unit 02. Furthermore, the drive unit 01, for example, in the region of the bearing unit 02, has two gearwheels 17 which are attached to the first and second shafts respectively and serve to synchronously drive the second shaft. The two shafts 10, 14 can preferably be made of tempered steel. The shafts are guided into the compressor unit 03 through seals 18.

(7) The compressor unit 03 has a compressor housing 19 with a housing lid 20 on the axial end face facing away from the bearing unit 02. Inside the compressor housing 19, there are situated a main rotor 21 and a subsidiary rotor 22 which are positioned axially parallel to one another and bear mutually complementary, mutually engaging screw profiles. The rotors remain easily accessible for maintenance purposes, via the housing lid which is intended to be opened. The two rotors 21, 22 can, for example, consist of ceramic material, carbon or steel and do not have to be manufactured out of the same material as the shafts 10, 14, which expands the areas of application of the screw compressor.

(8) The first shaft 10 engages by its free end in a coaxial bore of the main rotor 21, while the second shaft 14 engages by its free end in a coaxial bore of the subsidiary rotor 22. The shafts 10, 14 thus drive the rotors 21, 22. The rotors 21, 22 are not mounted on the side of the rotors 21, 22 facing the housing lid 20. Between the end faces of the rotors 21, 22 and the inside of the housing lid 20, a pressure chamber in which the rotors 21, 22 convey the medium when they are rotated is formed. The housing lid 20 has an outlet 23 at which the medium is discharged. Furthermore, at the compressor housing 19, there is provided an inlet 24 via which the medium is sucked in. Through the dimensioning of the outlet 23, it is possible to set the pressure to be achieved on the pressure side of the screw compressor. If the screw compressor is to be adapted to a changed application, for example, the housing lid can be exchanged, with a changed outlet being provided in order to adapt the outlet pressure provided by the screw compressor.

(9) Finally, the compressor unit 03 has a compressor cooling jacket 25 which in turn comprises cooling channels in which the cooling agent flows. Preferably, cooling channels 26 which carry cooling agent and which are preferred components of the compressor cooling jacket 25 also continue in the housing lid 20. In this manner, the pressure chamber, which is formed on the pressure side of the rotors, can be cooled efficiently.

REFERENCE NUMBERS

(10) 01drive unit 02bearing unit 03compressor unit 04 05drive housing 06drive rotor 07drive stator 08drive cooling jacket 09 10first shaft 11first spindle bearing 12second spindle bearing 13 14second shaft 15third spindle bearing 16fourth spindle bearing 17gearwheels 18seals 19compressor housing 20housing cover 21main rotor 22subsidiary rotor 23outlet 24inlet 25compressor cooling jacket 26cooling channels