EP3152441A1

EP3152441A1 - Compression refrigeration machine having a spindle compressor

Info

Publication number: EP3152441A1
Application number: EP15727635.3A
Authority: EP
Inventors: Ralf Steffens
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-06-03
Filing date: 2015-06-03
Publication date: 2017-04-12
Also published as: CN106536935A; US20170089342A1; KR20170013345A; JP2017518463A; US10337515B2; WO2015185624A1; DE102014008288A1; CN106536935B; AU2015270514B2; CA2951067A1; AU2015270514A1

Abstract

The invention relates to a spindle compressors without operating fluid in the working chamber, comprising a 2-tooth spindle rotor (2) and a 3-tooth spindle rotor (3) in a surrounding compressor housing (8) and having preferably non-parallel axes of rotation of the two spindle rotors, in particular for use in compression refrigeration machines. According to the invention, in order to improve the efficiency while providing flexible power adaptation, a multi-stage spindle compressor (1) whose compressor housing (8) and whose spindle rotors (2 and 3) are cooled by means of a partial-flow branch-off (25) of liquid refrigerant (39) from the main refrigerant circuit (24) is used as a refrigerant compressor, wherein the compressor housing (8) is cooled in a controlled manner by means of refrigerant evaporation (9), the refrigerant vapor subsequently being fed to the inlet (10), and, for power adaptation, there are, in addition to the inlet feed (11), also post-inlet feeds (12) into the working space and there are, in addition to the outlet discharge (14) from the outlet chamber (13), also pre-outlet discharges (15), each having a separate control element.

Description

Compression chiller with screw compressor Prior art:

Drying compressors are gaining in importance in industrial compressor technology, because of increasing obligations in environmental regulations and rising operating and disposal costs and increased demands on the purity of the medium, the known wet-running compressor, such as liquid ring machines, rotary vane pumps and oil or water-injected screw compressors, more and more replaced by dry compacting machines. These machines include dry screw compressors, claw pumps, diaphragm pumps, piston pumps, scroll machines and Roots pumps. However, these machines have in common that they still do not meet today's demands in terms of reliability and robustness and size and weight while maintaining low price level and satisfactory efficiency.

To improve this situation, offer the known dry-compressing spindle compressors because they realize a typical high performance as a typical 2-wave displacement machines simply by the fact that they have the necessary multistage as so-called. "Conveyor thread" by connecting several closed working chambers on the number of wraps per displacement rotor reach extremely uncomplicated, but without requiring a working fluid in the workspace. In addition, an increased rotor speed is made possible by the non-contact rolling of the two oppositely rotating spindle rotors, so that based on the size of the same nominal suction and delivery rate increase. Here, dry-compacting spindle machines can be used both for applications in vacuum and for overpressure, the power requirement in the overpressure is naturally significantly higher, because in the overpressure range with final pressures well above 2 bar (absolute) up to 15 bar and even higher significantly greater pressure differences to be overcome.

In the patent DE 10 2013 009 040.7 is described for a dry-compressing spindle compressor, as about non-parallel axes of rotation of the two spindle rotors both a large internal compression ratio and a high number of stages while minimizing the internal leakage between the multiple successive working chambers between conveying gas inlet and Outlet is achieved. In compression refrigeration the compressor technology for this power range is still dominated by screw compressors, which require a working fluid in the working space, the desired power adjustment is usually done on elaborate spool. In addition, for higher network working pressures, two compressors in series are often needed, and the efficiency is rather moderately satisfactory.

This situation needs to be improved.

The object of the present invention is to operate the refrigerant compressor without operating fluid in the working space with improved efficiency for a compression refrigeration machine at the same time increased reliability even for high network working pressures with only one compressor machine at the same time highly flexible and easy power adjustment and at least partially hermetically sealed construction and at the same time the lowest possible noise.

According to the invention, this object is achieved in that the refrigerant compressor is designed as a multistage screw compressor machine (1), which transports preferably non-parallel axes of rotation, the gaseous refrigerant without operating fluid in the working space from the inlet (10) to the outlet collecting space (13), wherein the spindle rotors (2) and (3) as well as the surrounding compressor housing (8) by means of their own refrigerant evaporator (6) and (7) and (9) via respective regulatory organs (16), (17), (18.1 and 18.2) , (21), (22) and (23) in terms of pressure level and flow rate via a partial flow branch (25) of liquid refrigerant are each selectively cooled so that the clearance distances between the spindle rotors (2 and 3) and the compressor housing (8) remain unchanged for all operating conditions within desired limits, wherein the height of the network working pressures over the executed number of stages as a series connection ng of working chambers between the 2-toothed rotor (2) and the 3-toothed rotor (3) is realized in the compressor working space between the inlet (10) and outlet (13), and the highly flexible adjustment of the compressor capacity is achieved as required, in addition to the inlet feed (1) to the inlet (10) in the rotor longitudinal axis, there are still after-inlet feeds (12) into the working space as well as next to the outlet discharge (14) from the outlet collecting space (13) Outlet drains (15), wherein both the inlet feeds (1 1 and 12) and the outlet drains (14 and 15) are each equipped with its own regulator, so that the actually delivered refrigerant both in terms of volume flow and in terms Pressure increase for the respective operating state for the purpose of power adjustment by any combination including sequence-specific partial flow quantities of the individual inlet feeders (11 and 12) and outlet Transfers (14 and 15) can be selectively adjusted, wherein optionally also the injection (40) of liquid refrigerant with its own regulator (41) for power adjustment is proposed as well as the possibility of the drive motor of the screw compressor with a frequency converter (38) operate for speed variation for purposeful power adjustment; Furthermore, for applications in which the properties of the refrigerant (39) and / or the heat transfer amounts (32) and (33) to the respective internal rotor cooling are not sufficient to bring the refrigerant for evaporation, proposed according to the invention that then the respective internal rotor cooling ( 6) or (7) is designed as a heat exchanger according to DE 10 2013 009 040.7 for the liquid refrigerant, said liquid refrigerant is then discharged per spindle rotor, for example via pitot tube pump according to DE 10 2013 009 040.7 and then inventively novel for evaporator cooling (9 ) is performed for the compressor housing, application-specific for the rotor cooling (6) and (7) and mixed forms of heat exchanger and evaporator are possible; Moreover, the invention further proposes that the inner rotor bore surface for internal rotor cooling is configured such that parking pockets (34) and overflow ramps (35) are provided for improved heat transfer, which are carried out according to the respective heat transfer conditions in Rotorlängsachsrichtung different sizes and that of the refrigerant wetted surfaces of the rotor inner bores roughened in the sense of "non-smooth", grooved and grooved, also thread-like executable. Compared to the state of the art in compressors in compression refrigerating machines, a sudden progress is achieved by the aforementioned inventive features by the following advantages according to the invention:

1) Thus, the compressor efficiency is improved by the efficient heat dissipation during the multi-stage compression.

2) The efficient heat dissipation during compression is achieved by using the existing refrigerant anyway, so that the compressor machine no separate cooling facilities are required.

3) In addition, the spindle compressor works without own operating fluid in the working space, which is a significant advance over the prior art, because in the comparable screw compressors, an oil is needed as operating fluid in the working space.

4) At the same time, the spindle compressor achieves the desired compression values by virtue of its multi-stage design in only one machine, so that, compared to the state of the art, it is no longer necessary to use two compressor machines at higher pressure values.

5) At the same time the reliability and life of the compressor is improved because the spindle loader because of the lower radial and axial forces bearing load is lower with direct positive effects on the storage in terms of reliability and life and thus on the compressor and consequently on the entire compression refrigeration machine.

6) For the desired power adjustment can be dispensed with the previously complex and critical spool by virtually all volume flow and each pressure stage can be implemented with the inventive screw compressor on Nach-inlet and pre-outlet design compliant.

7) The spindle compressor is directly executable by its proposed design as a hermetically sealed machine and is thermodynamically always on the safe side.

8) Because of the high multi-stage pressure pulsations at the outlet are much lower than in today's screw compressors, so that the spindle compressor is much quieter.

The present invention will be further explained by means of the following illustrations:

Fig. 1 shows an example of the present invention, the schematic representation of the refrigerant circuit of a compression refrigeration machine with the screw compressor as a working machine. In this case, both the flow direction of the refrigerant including the different aggregate states are entered. Also clearly visible is the diversion of liquid refrigerant according to the invention for efficient cooling of the compressor components, namely spindle rotor pair and compressor housing. In addition, for the desired performance adjustment various post-inlet feeds (12) and pre-outlet discharges (15) shown, which by any combination with the inlet feeder (11) and the outlet-discharge (14) via the respective regulatory organs practically all allow desired volume flow and pressure value.

The screw compressor machine (1) is shown only schematically, wherein the structural design in the following illustration of FIG. 2 is shown by way of example.

FIG. 2 shows, by way of example for the present invention, a sectional view through the screw compressor machine as a core element in the circuit of the compression refrigerating machine, as shown in FIG. The preceding explanations are already so meaningful that a repetition is certainly unnecessary here.

Fig. 3 shows an example of the present invention is an enlarged view of a detailed version for internal rotor cooling via the refrigerant with regard to a possible design of said parking pockets (34) and the overflow ramps (35) to be designed such that on the one hand, the heat transfer to Refrigerant optimally and on the other hand also an efficient distribution of the refrigerant in the rotor longitudinal axis direction is achieved within the cooling bore surface. In addition, the heat transfer to the refrigerant is significantly affected by the design of this cooling bore surface, which is exemplified here as a jagged line to show the wetted surfaces of the rotor inner holes as roughened in the sense of "non-smooth", grooved and grooved, for example, in Shape of an internal thread.

Spindle compressor without operating fluid in the working space with a 2-toothed spindle rotor (2) and a 3-toothed spindle rotor (3) in a surrounding compressor housing (8) with preferably non ^¬ parallel axes of rotation of both spindle rotors in particular for use in compression refrigerating machines. In order to improve the efficiency with flexible power adjustment, the invention proposes that a multi-stage screw compressor (1) is used, the compressor housing (8) and its spindle rotors (2 and 3) via a partial flow branch (25) of liquid refrigerant (39) are cooled from the main refrigerant circuit (24), wherein the compressor housing (8) is cooled in a controlled manner via refrigerant evaporation (9) with subsequent supply of the refrigerant vapor to the inlet (10) and that it is adapted to match the intake Feed (11) still post-inlet feeds (12) in the working space as well as next to the outlet-discharge (14) from the outlet chamber (13) still pre-outlet discharges (15), each with its own regulatory body.

LIST OF REFERENCE NUMBERS

1. Multi-stage screw compressor machine with preferably non-parallel spindle rotor axes of rotation

2. 2-toothed spindle rotor 3-tooth spindle rotor Carrier shaft for 2-tooth spindle rotor (2) with double-sided spindle rotor bearing, working space shaft seal, cooling fluid supply and synchronization gear carrier shaft for 3-tooth spindle rotor (3) with double-sided spindle rotor bearing, working area shaft seal, cooling fluid supply and synchronization gear Rotor internal cooling for the 2-toothed spindle rotor (2), preferably as a refrigerant evaporator, if under the spindle rotor conditions (such as diameter and speed) the properties of the selected refrigerant as well as the heat transfer amounts (32) for evaporation of the refrigerant in the cooling hole of the 2- toothed spindle rotor (2) suffice,

otherwise, the internal rotor cooling (6) for the 2-tooth spindle rotor (2) is carried out as a heat exchanger according to DE 10 2013 009 040.7,

or application-specific as a mixed form of evaporator and heat exchanger simultaneously internal rotor cooling for the 3-toothed spindle rotor (3), preferably as a refrigerant evaporator, if under the spindle rotor conditions (such as diameter and speed), the properties of the selected refrigerant as well as the heat transfer amounts (33) for an evaporation of the refrigerant in the cooling hole of the 3-toothed spindle rotor (3) suffice,

otherwise the internal rotor cooling (7) for the 3-toothed spindle rotor (3) is carried out as a heat exchanger according to DE 10 2013 009 040.7,

or application-specific also as mixed form of evaporator and heat exchanger at the same time compressor housing with an enveloping metal jacket similar to DE 0 2012 011 823.6 Refrigerant evaporator cooling for the preferably ribbed surface of the compressor housing inlet collecting space of the screw compressor for the gaseous refrigerant inlet supply with regulator for the gaseous refrigerant After Inlet feeds with respective gaseous refrigerant regulation means Outlet collecting space of the gaseous refrigerant screw compressor Outlet discharge with gaseous refrigerant regulating member Pre-discharge discharges with respective gaseous refrigerant regulating means Liquid-refrigerant supply to 2z-rotor inner Evaporator cooling with regulator Liquid-refrigerant supply to the 3z rotor interior evaporator cooling with regulator liquid refrigerant feeds to the compressor housing evaporator cooling with

18.1 a central regulator for smaller refrigerant scroll compressors

18.2 each individually own regulatory body for large refrigerant screw compressor evaporator openings in the compressor housing enclosing metal jacket for the compressor housing evaporator cooling (9) to the outside hermetically sealed collecting space for the vaporized housing refrigerant passage with regulating member for forwarding the housing refrigerant vapor passage With regulator for forwarding the 2z rotor internal refrigerant vapor passage with regulating member for forwarding the 3z rotor internal refrigerant vapor main flow circuit for the refrigerant, with representation of the flow direction diverted partial flow of liquid refrigerant for cooling the screw compressor condenser for the refrigerant in the main flow circuit Evaporator for the refrigerant in the main flow circuit drive power for the screw compressor heat transfer to the housing cooling (9) heat dissipation in the refrigerant condenser (26) heat absorption in the Kä Refrigerant evaporator (27) Heat transfer to 2z rotor internal cooling (6) Heat transfer to 3z rotor internal cooling (7) Parking pockets for the liquid refrigerant for internal rotor cooling Overflow ramps between the parking pockets (34) for internal rotor cooling Expansion valve as throttle for the liquid refrigerant in the main flow circuit Branch for the liquid refrigerant for cooling the spindle compressor components Frequency converter for the drive motor Refrigerant, which constantly passes through 2 aggregate states in the refrigerant circuit :

As liquid refrigerant (shown in hexagonal hatching, as closed hexa-rings)

• as gaseous refrigerant (shown in dotted hatching) Injection of liquid refrigerant into the compressor working space Regulator for refrigerant injection into the compressor working space

Claims

A compression refrigerating machine having a refrigerant main circuit (24) containing refrigerant (39) and a scroll compressor formed as a two-shaft rotary displacement machine operating in the working space without operating fluid for conveying and compressing gaseous fluids; the spindle compressor comprising a 2-toothed spindle rotor (2), a 3-toothed spindle rotor (3) and a compressor housing (8) surrounding the spindle rotors (2, 3), comprising an inlet space (10) and an outlet collecting space (13). Has,

where egg

the screw compressor (1) is a multi-stage screw compressor (1), the main refrigerant circuit (24) has a partial flow branch (25), and the compressor housing (8) and the spindle rotors (2 and 3) via the partial flow branch (25 ) are cooled with liquid refrigerant (39) from the refrigerant main circuit (24).

2. compression refrigerating machine with screw compressor according to claim 1,

characterized in that

the heat of compression from the compressor housing (8) via refrigerant evaporation (9) is discharged, wherein liquid refrigerant is conducted by means of the partial flow branch (25) via a regulating member (18) to a housing-refrigerant evaporation (9) and over The refrigerant vapor exiting the openings (19) from the refrigerant evaporation (9) passes into a collecting space (20), and that this refrigerant vapor then flows into the inlet space (10) through a passage (21) in which the regulating member (18) is located ) of the screw compressor machine (1) flows.

3. compression refrigerating machine with screw compressor according to claim 1 and 2,

characterized in that

the spindle rotors (2 and 3) each have a large cooling bore, that the heat of compression from the spindle rotors (2 and 3) in their cooling hole via refrigerant evaporation (6 and 7) is discharged when under the spindle rotor conditions (such as diameter and speed) the properties of the selected refrigerant as well as the heat transfer amounts (32 and 33) are sufficient for evaporation of the respective supplied refrigerant, wherein liquid refrigerant by means of the partial flow branch (25) targeted by each regulatory organ (16 and 17) to the respective rotor refrigerant Evaporation (6 and 7) is guided in each Spindelrotorkühlbohrung and the via the respective openings (22 and 23) with the regulating member (18) from the respective spindle rotor refrigerant evaporation (6 and 7) exiting refrigerant vapor into the inlet chamber (10) is guided ,

4. compression refrigeration machine with screw compressor according to claim one of claims 1 to 3, characterized in that the axes of rotation of the two spindle rotors (2 and 3) are not parallel.

5. Spindle compressor according to claim 1 and 2,

characterized in that

the heat of compression of the spindle rotors (2 and 3) is dissipated in their large cooling hole via liquid refrigerant as known heat exchanger according to DE 2013009040, if under the spindle rotor conditions (such as diameter and speed) the properties of the selected refrigerant as well as the heat transfer amounts (32 and 33) are not sufficient for evaporation, this liquid refrigerant is then discharged per spindle rotor, for example via pitot tube pump according to DE 102013009040 and then according to the invention led to novel evaporator cooling (9) for the compressor housing, where this then according to claim 2 also in the inlet space ( 10) of the screw compressor machine (1) passes.

6. Spindle compressor according to claim 1 and 2 and 4,

characterized in that

Application-specific for the rotor cooling (6) and (7) and mixed forms as a heat exchanger according to claim 4 and as an evaporator according to claim 2 combined and work together.

7. Spindle compressor according to the preceding claims,

characterized in that

the said cooling means (6 and 7 and 9) for the screw compressor components (2 and 3 and 8) via the respective regulating members (16), (17), (18.1 or 18.2), (21), (22) and ( 23) in terms of pressure level and flow rate are each used so targeted that the clearance distances between the spindle rotors (2 and 3) and the compressor housing (8) remain unchanged for all operating conditions within desired limits.

8. Spindle compressor according to one of the preceding claims,

characterized in that

In addition to the inlet feed (11) to the inlet space (10) in the rotor longitudinal axis, there are still inlet feeders (12) into the working space as well as beside the outlet discharge (14) from the outlet collecting space (13). Outlet drains (15), wherein both the inlet feeders (12 and 12) and the outlet drains (14 and 15) are each equipped with their own regulator, so that the actually delivered refrigerant both in terms of volume flow and in terms of pressure increase for power adjustment specifically targeted to the respective operating state by any combination including sequence-appropriate partial flow amounts of the individual inlet feeders (11 and 12) and outlet discharges (14 and 15).

9. Spindle compressor according to one of the preceding claims,

characterized in that

for targeted power adjustment to different operating conditions via a regulating member (41) nor the injection (40) of liquid refrigerant is provided in the working space and / or the ability to drive the drive motor of the screw compressor with a frequency converter (38) for speed variation for the purpose of targeted performance adjustment.

10. Spindle compressor according to one of the preceding claims,

characterized in that

the inner spindle rotor bore surface for internal rotor cooling is designed such that parking pockets (34) and overflow ramps (35) are provided for improved heat transfer, which are carried out differently sized according to the respective heat transfer conditions in Rotorlängsachsrichtung to both the respectively suitable residence time of the refrigerant for heat absorption as also to ensure the extensive distribution of the refrigerant over the entire cooling bore surface.

11. Spindle compressor according to one of the preceding claims,

characterized in that

that the surfaces of the rotor inner bores wetted by the refrigerant are roughened in the sense of "non-smooth", ribbed and grooved, are also designed to be thread-shaped in order to increase the heat transfer surface wetted by the refrigerant and to selectively manipulate the flow movement of the refrigerant.