Spindle compressor using refrigerant cooling for housing and rotor

Abstract

The invention relates to a spindle compressor without operating fluid in the working space with a 2-tooth spindle rotor and a 3-tooth spindle rotor in a surrounding compressor housing-and preferably non-parallel rotation axes of the two spindle rotors, in particular for use in compression refrigeration machines. In order to improve the degree of efficiency while providing flexible power adjustment, it is proposed according to the invention that a multi-stage spindle compressor be used as a refrigerant compressor, whose compressor housing and whose spindle rotors are cooled via a partial-flow branch-off of liquid refrigerant from the refrigerant main flow circuit, wherein the compressor housing is cooled in a controlled manner by means of refrigerant evaporation, with the refrigerant vapor being subsequently fed to the inlet, and that, for power adjustment, there are also post-inlet feeds into the working space in addition to the inlet feed, and also pre-outlet discharges in addition to the outlet discharge from the outlet space, each with their own regulating device.

Claims

1. A compression refrigeration machine comprising a refrigerant main flow circuit, refrigerant located in the refrigerant main flow circuit, and a dry-compressing spindle compressor for conveying and compressing gaseous refrigerant, the spindle compressor having a working space and being configured as a 2-shaft rotation compressor machine having a 2-tooth spindle rotor, a 3-tooth spindle rotor and a compressor housing which surrounds the spindle rotors and has an inlet space and a housing collecting space, wherein the spindle compressor is a multi-stage spindle compressor, the refrigerant main flow circuit has a partial-flow branch-off, and the compressor housing and the 2-tooth spindle rotor and the 3-tooth spindle rotor are cooled via the partial-flow branch-off with liquid refrigerant from the refrigerant main flow circuit.

2. The compression refrigeration machine according to claim 1, wherein compression heat is dissipated from the compressor housing by refrigerant evaporation, wherein liquid refrigerant is routed via the partial-flow branch-off via a first regulator to a housing refrigerant evaporation system and the gaseous refrigerant escaping from the housing refrigerant evaporation system is routed to a vapor refrigerant collecting space, and the gaseous refrigerant flows from the vapor refrigerant collecting space through a second regulator in a first passageway and into the inlet space.

3. The compression refrigeration machine according to claim 2, wherein the rotation axes of the 2-tooth spindle rotor and the 3-tooth spindle rotor extend in a non-parallel manner.

4. The compression refrigeration machine according to claim 1, wherein the 2-tooth spindle rotor and the 3-tooth spindle rotor each have a cooling bore, and compression heat is dissipated from the 2-tooth spindle rotor and the 3-tooth spindle rotor through their respective cooling bore by refrigerant evaporation.

5. The compression refrigeration machine according to claim 1, wherein the rotation axes of the 2-tooth spindle rotor and the 3-tooth spindle rotor extend in a non-parallel manner.

6. The compression refrigeration machine according to claim 1, wherein unevaporated liquid refrigerant is conveyed away from each of the 2-tooth spindle rotor and the 3-tooth spindle rotor and is routed to an evaporator cooling system for the compressor housing.

7. The compression refrigeration machine according to claim 1, wherein the clearance distances between the 2-tooth spindle rotor and the 3-tooth spindle rotor and the compressor housing are maintained unchanged within pre-selected limits for all operating states.

8. The compression refrigeration machine according to claim 1, wherein at least one inlet feed to the inlet space is provided, and there are provided, in the longitudinal rotor axis direction, post-inlet feeds into the working space and wherein at least one outlet discharge extending from the housing outlet collecting space is provided, and pre-outlet discharges are provided in addition to the outlet discharge, wherein both the inlet feed and the outlet discharge are each provided with a regulator.

9. The compression refrigeration machine according to claim 1, further including a regulator for the injection of liquid refrigerant into the working space.

10. The compression refrigeration machine according to claim 1, wherein an inner surface of the 2-tooth spindle rotor and the 3-tooth spindle rotor includes parking recesses and overflow for improved heat transfer.

11. The compression refrigeration machine according to claim 1, wherein inner surfaces of the 2-tooth spindle rotor and the 3-tooth spindle rotor wetted by the refrigerant are one or more of roughened, grooved or furrowed, or configured in a thread-like manner.

12. The compression refrigeration machine according to claim 1, wherein a frequency converter is provided for driving a drive motor of the spindle compressor, and the rotary speed of the drive motor may be varied for the purpose of power adjustment.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) FIG. 1 schematically shows a refrigerant circuit of a compression refrigerqation machine;

(2) FIG. 2 schematically shows a sectional view of a spindle compressor machine of the compression refrigeration machine shown in FIG. 1; and

(3) FIG. 3 schematically shows a sectional view of a interior rotor cooling configuration.

DETAILED DESCRIPTION OF EMBODIMENTS

(4) The present invention is explained in more detail by means of the following illustrations:

(5) FIG. 1 shows, by way of example for the present invention, the schematic illustration regarding the refrigerant circuit of a compression refrigeration machine with the spindle compressor as a working machine. In this case, the flow direction of the refrigerant including the various aggregate states is drawn in. The branch-off of liquid refrigerant according to the invention for the efficient cooling of the compressor components, i.e. the spindle rotor pair and the compressor housing, is also easily recognizable. Furthermore, various post-inlet feeds 12 and pre-outlet discharges 15 for the desired power adjustment are shown, which, according to the design, make virtually any desired volume flow and pressure value possible by any combination also with the inlet feed 11 and the outlet discharge 14 through the respective regulating devices.

(6) The spindle compressor machine 1 is shown only schematically, with its construction being shown by way of example in the following representation of FIG. 2.

(7) FIG. 2 shows, by way of example for the present invention, a sectional view through the spindle compressor machine as a core element in the circuit of the compression refrigeration machine as shown in FIG. 1. The previous explanations are already so informative that any repetition would in this case doubtless be unnecessary.

(8) By way of example for the present invention, FIG. 3 shows an enlarged representation of a detailed configuration of the rotor interior cooling by means of the refrigerant with respect to a possible design of the above-mentioned parking recesses 34 and the overflow ramps 35, which are to be configured in such a way that, on the one hand, the heat transfer to the refrigerant takes place in an optimum manner and, on the other hand, an efficient distribution of the refrigerant in the longitudinal rotor axis direction within the cooling bore surface is achieved. Furthermore, the heat transfer to the refrigerant is significantly influenced by the configuration of this cooling bore surface, which in this case is shown by way of example as a saw-toothed line in order to present the surfaces of the rotor interior bores wetted by the refrigerant as roughened, in the sense of non-smooth, grooved and furrowed, also in the form of an internal thread, for example.

(9) The spindle compressor operating without operating fluid in the working space comprises a 2-tooth spindle rotor 2 and a 3-tooth spindle rotor 3 in a surrounding compressor housing 8 and preferably non parallel rotation axes of the two spindle rotors, in particular for use in compression refrigeration machines. In order to improve the degree of efficiency while providing flexible power adjustment, it is proposed according to the invention that a multi-stage spindle compressor 1 be used as a refrigerant compressor, whose compressor housing 8 and whose spindle rotors 2, 3 are cooled via a partial-flow branch-off 25 of liquid refrigerant 39 from the refrigerant main flow circuit 24, wherein the compressor housing 8 is cooled in a controlled manner by means of refrigerant evaporation 9, with the refrigerant vapor being subsequently fed to the inlet 10, and that, for power adjustment, there are also post-inlet feeds 12 into the working space in addition to the inlet feed 11, and also pre-outlet discharges 15 in addition to the outlet discharge 14 from the outlet space 13, each with their own regulating device.

(10) In one embodiment, the compression refrigeration machine has a refrigerant main flow circuit 24 in which refrigerant 39 is located and a spindle compressor configured as a 2-shaft rotation compressor machine, which operates without operating fluid in the working space, for conveying and compressing gaseous delivery media, the spindle compressor having a 2-tooth spindle rotor 2, a 3-tooth spindle rotor 3 and a compressor housing 8 which surrounds the spindle rotors 2, 3 and has an inlet space 10 and an outlet collecting space 13, wherein the spindle compressor 1 is a multi-stage spindle compressor 1, the refrigerant main flow circuit 24 has a partial-flow branch-off 25, and the compressor housing 8 and the spindle rotors 2, 3 are cooled via the partial-flow branch-off 25 with liquid refrigerant 39 from the refrigerant main flow circuit 24.

(11) In another embodiment, the compression heat is dissipated from the compressor housing 8 by means of refrigerant evaporation 9, wherein liquid refrigerant is routed by means of the partial-flow branch-off 25 via a regulating device 18 to a housing refrigerant evaporation system 9 and the refrigerant vapor escaping from the refrigerant evaporation system 9 via the openings 19 arrives in a collecting space 20, and that this refrigerant vapor then flows through a passageway 21 in which the regulating device 18 is located into the inlet space 10 of the spindle compressor machine 1.

(12) In another embodiment the spindle rotors 2, 3 each have a large cooling bore, that the compression heat is dissipated from the spindle rotors 2, 3 in each case in their cooling bores by means of refrigerant evaporation 6, 7 if, under the spindle rotor conditions (such as diameter and rotary speed), the properties of the selected refrigerant and the heat transfer amounts 32, 33 are sufficient for an evaporation of the respectively supplied refrigerant, wherein liquid refrigerant is specifically routed, by means of the partial-flow branch-off 25 and in each case by means of the regulating device 16, 17, into each spindle rotor cooling bore for the respective rotor refrigerant evaporation 6, 7, and the refrigerant vapor escaping via the respective openings 22, 23 with a regulating device 18 from the respective spindle rotor refrigerant evaporation 6, 7 is routed into the inlet space 10.

(13) In one embodiment, the rotation axes of the two spindle rotors 2, 3 extend in a non-parallel manner.

(14) In another embodiment, the compression heat is dissipated from the spindle rotors 2, 3 in each case in their large cooling bores via liquid refrigerant as a known heat exchanger as described in DE 2013 009 040 if, under the spindle rotor conditions (such as diameter and rotary speed), the properties of the selected refrigerant and the heat transfer amounts 32, 33 are insufficient for an evaporation, wherein this liquid refrigerant is then conveyed away for each spindle rotor by means of, for example, a pitot tube pump in accordance with DE 10 2013 009 040 and is then, according to the invention and in a novel manner, routed to the evaporator cooling system 9 for the compressor housing, where it then also arrives as described above in the inlet space 10 of the spindle compressor machine 1.

(15) In yet another embodiment, the cooling systems 6, 7, 9 described above for the spindle compressor components 2, 3, 8 are in each case used specifically, by means of the respective regulating devices 16, 17, 18.1, 18.2, 21, 22, 23 with respect to the pressure level and the flow rate, that the clearance distances between the spindle rotors 2, 3 and to the compressor housing 8 are maintained unchanged within desired limits for all operating states.

(16) In another embodiment, there are, in the longitudinal rotor axis direction, post-inlet feeds 12 into the working space in addition to the inlet feed 11 to the inlet space 10, and also pre-outlet discharges 15 in addition to the outlet discharge 14 from the outlet collecting space 13, wherein both the inlet feeds 11, 12 and the outlet discharges 14, 15 are each provided with their own regulating device, so that the actually conveyed refrigerant becomes specifically adjustable both with regard to the volume flow and the pressure increase for the power adjustment to the respective operating state, specifically by means of any combination, including the consequential partial flow amounts of the individual inlet feeds 11, 12 and outlet discharges 14, 15.

(17) In another embodiment, the specific power adjustment to different operating states by means of a regulating device, the injection of liquid refrigerant into the working space is also provided, and/or the option of driving the drive motor of the spindle compressor with a frequency converter 38 in order to vary the rotary speed for the purpose of a specific power adjustment.

(18) In another embodiment, the inner spindle rotor bore surface for rotor interior cooling is configured in such a way that parking recesses 34 and overflow ramps 35 are provided for an improved heat transfer, which are configured with different sizes corresponding to the respective heat transfer conditions in the longitudinal rotor axis direction in order to ensure both the respectively suitable retention time of the refrigerant for heat absorption and the comprehensive distribution of the refrigerant on the entire cooling bore surface.

(19) In another embodiment, the surfaces of the rotor interior bores wetted by the refrigerant are roughened, in the sense of non-smooth, grooved and furrowed, also configured in a thread-like manner, for increasing the heat transfer surface wetted by the refrigerant and for specifically manipulating the flow movement of the refrigerant. 1. Multi-stage spindle compressor machine with preferably non-parallel spindle rotor rotation axes 2. 2-tooth spindle rotor 3. 3-tooth spindle rotor 4. Support shaft for the 2-tooth spindle rotor (2) with bilateral spindle rotor bearing, working space shaft seal, cooling fluid feed and synchronization gear wheel 5. Support shaft for the 3-tooth spindle rotor (3) with bilateral spindle rotor bearing, working space shaft seal, cooling fluid feed and synchronization gear wheel 6. Rotor interior cooling system for the 2-tooth spindle rotor (2), preferably as a refrigerant evaporator if, under the spindle rotor conditions (such as diameter and rotary speed), the properties of the selected refrigerant and the heat transfer amounts (32) are sufficient for an evaporation of the refrigerant in the cooling bore of the 2-tooth spindle rotor (2), otherwise, the rotor interior cooling system (6) for the 2-tooth spindle rotor (2) is configured as a heat exchanger in accordance with DE 10 2013 009 040.7, or, application-specific, also as a mixed form of an evaporator and a heat exchanger at the same time 7. Rotor interior cooling system for the 3-tooth spindle rotor (3), preferably as a refrigerant evaporator if, under the spindle rotor conditions (such as diameter and rotary speed), the properties of the selected refrigerant and the heat transfer amounts (33) are sufficient for an evaporation of the refrigerant in the cooling bore of the 3-tooth spindle rotor (3), otherwise, the rotor interior cooling system (7) for the 3-tooth spindle rotor (3) is configured as a heat exchanger in accordance with DE 10 2013 009 040.7, or, application-specific, also as a mixed form of an evaporator and a heat exchanger at the same time 8. Compressor housing with an encapsulating sheet-metal jacket, similar to DE 10 2012 011 823.6 9. Refrigerant evaporator cooling system for the preferably ribbed surface of the compressor housing 10. Inlet collecting space of the spindle compressor for the gaseous refrigerant 11. Inlet feed with a regulating device for the gaseous refrigerant 12. Post-inlet feeds with respective regulating devices for the gaseous refrigerant 13. Outlet collecting space of the spindle compressor for the gaseous refrigerant 14. Outlet discharge with a regulating device for the gaseous refrigerant 15. Pre-outlet discharges with respective regulating devices for the gaseous refrigerant 16. Liquid refrigerant feed to the 2-tooth rotor interior evaporator cooling system with a regulating device 17. Liquid refrigerant feed to the 3-tooth rotor interior evaporator cooling system with a regulating device 18. Liquid refrigerant feeds to the compressor housing evaporator cooling system with 18.1 a central regulating device for smaller refrigerant spindle compressors 18.2 in each case individual, separate regulating devices for large refrigerant spindle compressors 19. Evaporator openings in the sheet-metal jacket encapsulating the compressor housing for the compressor housing evaporator cooling system (9) 20. Collecting space that is hermetically sealed towards the outside for the evaporated housing refrigerant 21. First passageway with a regulating device for passing on the housing refrigerant vapor 22. Second passageway with a regulating device for passing on the 2-tooth rotor interior refrigerant vapor 23. Third passageway with a regulating device for passing on the 3-tooth rotor interior refrigerant vapor 24. Main flow circuit for the refrigerant, with an illustration of the flow direction 25. Branched-off partial flow of liquid refrigerant for cooling the spindle compressor 26. Condenser for the refrigerant in the main flow circuit 27. Evaporator for the refrigerant in the main flow circuit 28. Drive power for the spindle compressor 29. Heat transfer to the housing cooling system (9) 30. Heat dissipation in the refrigerant condenser (26) 31. Heat absorption in the refrigerant evaporator (27) 32. Heat transfer to the 2-tooth rotor interior cooling system (6) 33. Heat transfer to the 3-tooth rotor interior cooling system (7) 34. Parking recesses for the liquid refrigerant for rotor interior cooling 35. Overflow ramps between the parking recesses (34) for rotor interior cooling 36. Expansion valve as a throttle for the liquid refrigerant in the main flow circuit 37. Branch-off for the liquid refrigerant for cooling the spindle compressor components 38. Frequency converter for the drive motor 39. Refrigerant constantly passing through 2 states of aggregation in the refrigerant circuit as a liquid refrigerant (depicted with hexagonal hatching, as closed hexagonal rings) as a gaseous refrigerant (depicted with dotted hatching)