COMPRESSOR, ESPECIALLY SCREW COMPRESSOR, AND REFRIGERATION CIRCUIT WITH A COMPRESSOR

Description

The present invention relates to a compressor, in particular a screw compressor, in particular a compact screw compressor, for compressing a working medium with the features of claim 1. Furthermore, the present invention relates to a refrigerant circuit having a screw compressor, in particular a compact screw compressor with the features of claim 24.

Such compressors, in particular screw compressors, are known from the prior art in various designs. For example, from EP 1 036 276 A1 a generic screw compressor is known that has a demister arranged in an outer housing, wherein a working medium compressed by a compression device is conducted through at least one compressor outlet into an interior space arranged in the outer housing. A demister is arranged in the interior space in a flow path between the compression device and the outlet opening. Such screw compressors are also called compact screw compressors if an oil separator is arranged inside the outer housing. An external oil separation device with an oil return is therefore not needed.

In the prior art, demisters are also referred to as “demistors,” “mist eliminators,” droplet separators or, more generally, oil separators and are used to separate oil droplets from the working medium, which is a refrigerant, for example.

Demisters are arranged in generic compressors, in particular compact screw compressors, in an interior space of the outer housing, wherein the oil droplets, as a mixture of working medium and lubricant, can settle in the interior space in a flow path between a compressor outlet and the outlet opening. Due to inertia, redirecting the oil droplets in the demister causes the oil droplets to not follow the gas flow of the working medium and strike the demister. Larger oil drops can get stuck in the demister or, due to gravity, fall into an oil sump downstream of the demister.

The screw compressors known from the prior art have proven themselves in the past, but it has been found that, in particular in screw compressors, in some operating conditions the working medium leaving the screw compressor carries too many oil droplets.

This is where the present invention comes in.

The underlying object of the invention is therefore to propose an improved screw compressor that expediently eliminates the disadvantages known from the prior art. Oil separation should preferably be improved, so that the working medium discharged by the proposed screw compressor carries as few oil droplets as possible and/or a particularly compact design is enabled.

These objects are achieved using a screw compressor having the features of claim 1. Further advantageous embodiments of the present invention are specified in the dependent claims.

The inventive compressor, in particular the inventive screw compressor, having the features of claim 1 for compressing a working medium comprises an outer housing with an inlet opening, an outlet opening and a longitudinal axis.

The working medium, for example from a refrigeration circuit, can enter the screw compressor for compression through the inlet opening and the compressed working medium can be released into the refrigeration circuit through the outlet opening.

Furthermore, the inventive screw compressor comprises a drivable compression device arranged in the outer housing and having at least one rotor rotatable about a rotational axis, wherein the rotational axis is preferably arranged parallel to the longitudinal axis.

Furthermore, the inventive compressor comprises at least one compressor outlet, wherein the at least one compressor outlet conducts the working medium compressed by the compression device into an interior space arranged in the outer housing.

Along a flow path between the compressor outlet and the outlet opening of the outer housing, the interior space forms a cross-sectional expansion in which the working medium can be sharply decelerated downstream of the compressor outlet.

A first demister is arranged in the interior space, wherein the at least one compressor outlet is oriented towards the first demister, preferably in at least one outlet direction, in order to cause the compressed working medium, or the mixture with the compressed working medium and the lubricant, to flow to or be shot at or sprayed at the first demister.

It is noted that in the context of this invention flowing to, shooting at, and spraying at have the same meaning.

The present invention is based on the idea of preferably shooting a demister positioned upstream of a free end of the compressor outlet with a jet of the compressed working medium, so that in particular oil separation is improved. Furthermore, the proposed design enables compact construction.

In the shot at first demister, which, in particular, comprises a wire mesh, a large portion of the oil contained in the compressed working medium is preferably separated and can collect there in an oil sump arranged in a lower region of the interior space and drain off.

The compressed working medium is essentially redirected radially upstream of or in the first demister to the at least one outlet direction. Due to the redirection, the compressed working medium flows from the side of the first demister facing the at least one compressor outlet into or through the interior space to the outlet opening of the outer housing.

One further development of the present invention provides that a media-impermeable wall is arranged on the side of the first demister facing away from the at least one compressor outlet. The wall is preferably arranged downstream of the demister in the outlet direction, more preferably immediately downstream of the demister. The wall may preferably extend completely or only partially across the side of the first demister facing away from the at least one compressor outlet. The wall ensures that the jet of compressed working medium exiting the compressor outlet in the outlet direction does not “pass through” or “shoot through” the first demister and entrain oil droplets from it.

According to a preferred development of the present invention, the media-impermeable wall is formed by a first holder and/or by the outer housing. For example, the media-impermeable wall may be formed by a holder by which the first demister is also held in position in the outer housing. Alternatively, the first demister may be arranged on the outer housing or on the inside of the outer housing, the outer housing forming the media-impermeable wall for the first demister.

It is preferred for the first demister to have a demister plane. Furthermore, it may be advantageous for the first demister to be arranged in the demister plane substantially transverse to the at least one outlet direction. It is noted that, in the context of this invention, a demister plane substantially transverse to the at least one outlet direction is understood to mean a demister plane arranged perpendicular to the at least one outlet direction with an angular tolerance of ±15°, preferably ±10°, more preferably ±5°.

It is further noted that the at least one outlet direction may correspond to a vector that describes the flow field of the exiting compressed working medium at a free end of the compressor outlet.

Furthermore, it has proven advantageous for the first demister to be arranged spaced apart from the outer housing in the at least one outlet direction.

It has also proven advantageous for the first demister to be arranged spaced apart from the outer housing in at least one direction on the demister plane.

The spaced-apart arrangement in the outlet direction to the outer housing, in particular using the aforementioned holder, may always be advantageous when the outer housing, for example, has a large curvature that prevents the preferably plate-like or disc-like first demister from being arranged flush against the outer housing.

The spaced-apart arrangement in a demister plane transverse to the outlet direction to the outer housing makes it possible to position the first demister such that it does not project into the oil sump in the interior. It may also be advantageous for the first demister to project into the oil sump to ensure that the oil reliably drips into the oil sump.

Furthermore, it may be advantageous for the first demister to abut the outer housing in at least one direction on the demister plane. For example, it may be advantageous for the first demister to at least partially abut the outer housing in the lower region of the outer housing. In such a design, the first demister can project into the oil sump.

The outlet direction of the compressor outlet may preferably be intentionally arranged transverse to the direction of gravity.

According to a preferred further development of the present invention, at least one second demister is arranged in the interior space in a flow path between the compressor outlet and the outlet opening. It may be particularly advantageous for a plurality of second demisters to be provided in order to realize further separation stages, so that oil separation can be further improved. The second demisters are preferably connected in series, wherein even more preferably the second demisters are arranged spaced apart from one another at a third distance. The at least one second demister is preferably arranged in a respective second demister plane and the respective second demister plane is further preferably arranged parallel to the demister plane of the first demister.

According to a further preferred embodiment, the at least one compressor outlet is passed through the at least one second demister. This can result in a particularly compact design.

Furthermore, it has proven advantageous for the at least one second demister to comprise a second holder. The second holder preferably additionally has at least one through-opening through which the working medium can flow through the second holder. The second holder is preferably arranged downstream of the respective at least one second demister and holds or supports the at least one second demister in the interior space. The at least one through-opening is arranged in a first section of the second holder, wherein the first section may be designed, for example, in the manner of a perforated or grid plate.

The at least one through-opening may be round, oval, polygonal, or hexagonal. In particular, it is preferred for a plurality of through-openings having the same and/or different shapes to be provided. The holder may also have a spoke-like design. The aim is to create the lowest possible flow resistance, but to provide sufficient support structure for the wire mesh in order to position the latter securely in the interior.

According to a preferred further development, the at least one through-opening may be round, oval, polygonal and/or hexagonal. In particular, it is preferred for a plurality of through-openings of the same and/or different shapes to be provided. The holder may also have a spoke-like design. The shape of the through-openings can reduce the flow resistance of the second holder and can also provide a support structure for the wire mesh in order to position the latter securely in the interior. In particular, it is preferred for the at least one through-opening to be hexagonal. The plurality of through-openings may preferably be arranged in a honeycomb shape.

However, the at least one through-opening may also be round or polygonal or have a mixture of these shapes. The holder may also be designed in a spoke-like manner, so that the at least one through-opening can be given such a mixture.

One further development of the present invention provides that the second holder has the first section and a second section, wherein the second section is designed to be media-impermeable. The second section can help ensure that the working fluid follows the longest possible flow path through the interior, so that so-called “bypasses”to the outlet opening of the housing can be avoided.

Furthermore, it has proven advantageous for the second holder to have at least one cut-out through which the at least one compressor outlet is passed. The at least one cut-out may be adapted to the shape of the compressor outlet, so that leakage flows between the second holder and the compressor outlet can be avoided.

A further development of the present invention provides that the first section and the second section are arranged on diametrical sides of the at least one cut-out. In particular, it is preferred for the first section to be arranged at the bottom with respect to the direction of gravity and the second section to be arranged at the top.

A further development of the present invention provides that the at least one second demister is attached to the at least one compressor outlet and/or to the outer housing. In one exemplary embodiment, the at least one second demister may be fixedly connected to the compressor outlet, so that the outer housing, in particular a pressure bell of the outer housing, can be fitted over the at least one second demister during assembly. This enables particularly simple and cost-effective assembly.

The present invention provides that the first demister is arranged spaced apart from the at least one compressor outlet at a first distance in the outlet direction. Accordingly, the first demister is arranged upstream of the compressor outlet in the outlet direction, wherein the first distance is typically on the order of 5-50 mm. The small first distance, for example approx. 10 mm, between the first demister and the compressor outlet ensures a high shot density of the compressed working medium.

According to a further advantageous embodiment, the at least one second demister is arranged spaced apart from the first demister at a second distance, preferably along the longitudinal axis and/or in the orientation of the outlet direction. It is preferred for the first distance between the at least one compressor outlet and the first demister to be smaller than the second distance between the first demister and the second demister. In particular, it is preferred for the second distance to be at least twice the first distance. In particular, it is even more preferred for the second distance to be at least 50 mm. The second distance ensures that the second demister is flowed through evenly. This can improve oil separation.

It is advantageous for the first demister and/or the second demister to comprise a wire mesh, wherein the wire mesh is preferably made of round wire and/or flat wire.

The first demister and/or the second demister may preferably be plate-like or disc-like in a demister plane, wherein the demister plane is preferably arranged transversely to the existing flow direction or the longitudinal axis in the interior space.

A further development of the present invention provides that the outer housing comprises a pressure bell forming the interior, and that the first demister and/or the at least one second demister is or are arranged in the pressure bell. The pressure bell can be fitted over the at least one compressor outlet to form the interior space, wherein the interior space is formed between the compressor outlet and the pressure bell.

Furthermore, it has proven advantageous for the pressure bell to have the outlet opening of the outer housing. Furthermore, it is advantageous for the outlet opening to be arranged in an upper region that is arranged on the side opposite the lower region. In other words, the outlet opening is arranged in the upper region of the outer housing.

It has also proven advantageous for the outlet opening to be arranged spaced apart from the free end of the at least one compressor outlet against the outlet direction. Accordingly, the compressed working medium must be redirected by 180° after exiting from the at least one compressor outlet in the interior space in order to reach the outlet opening. On the one hand, this allows a particularly compact design of the screw compressor to be realized and, on the other hand, it allows particularly effective oil separation. It may also be advantageous for the outlet opening to be arranged spaced apart from the at least one second demister against the outlet direction.

According to a preferred further development of the present invention, the at least one compressor outlet protrudes freely from the compression device. The working medium compressed by the rotors can preferably be conducted via an outlet channel of the compression device to the at least one compressor outlet, wherein it is further preferred for the at least one compressor outlet to be tubular. The at least one tubular compressor outlet may also be referred to as the at least one compressor outlet tube. The tubular compressor outlet may have any cross-section, wherein the cross-section is preferably circular.

Furthermore, it has proven advantageous for the at least one compressor outlet to have an S-shaped profile. Due to the S-shaped profile, the free end can be displaced towards the upper region of the outer housing, so that the free end of the at least one compressor outlet can be arranged spaced apart as far as possible from the oil sump arranged in the lower region in the interior.

Furthermore, it has proven advantageous for at least two compressor outlets to be provided and for the at least two compressor outlets to be arranged spaced apart from one another. The at least two compressor outlets are preferably arranged parallel to one another.

According to a preferred further development of the present invention, the compressor is a screw compressor. Further preferably, the at least one rotor is rotatable parallel to the longitudinal axis. Furthermore, it may be advantageous for the at least one outlet direction of the at least one compressor outlet to be oriented parallel or perpendicular to the longitudinal axis.

Furthermore, it has proven advantageous for at least one control slide to be provided that controls the output and/or adjusts the pressure ratio of the screw compressor. The at least one control slide is displaceable along the longitudinal axis or in a direction parallel to the rotational axis of the at least one rotor, wherein an actuating unit can actuate or displace the control slide. The actuating unit may be arranged between the at least two compressor outlets. As a result, the actuating unit influences the flow conditions in the interior space only slightly.

A further development of the present invention provides that a drive motor arranged in the outer housing drives the compression device. Furthermore, it may be advantageous for the drive motor to be cooled by the working medium. The drive motor is arranged on the side of the compression device facing away from the interior space and can be cooled by the working medium flowing through the inlet opening and to the compression device.

Furthermore, the present invention relates to a refrigeration circuit with a screw compressor as described above.

A refrigeration circuit and two exemplary embodiments of a screw compressor and their further developments are described in detail below with reference to the attached drawings. In the figures:

FIG. 1 shows a refrigeration system with a screw compressor;

FIG. 2 shows a first exemplary embodiment of the screw compressor according to FIG. 1, comprising an outer housing and a driven compression device arranged in the outer housing, and a compressor outlet that conducts the compressed working medium through the compression device into an interior space arranged in the outer housing, and wherein a first demister and a second demister are arranged in the interior space;

FIG. 3 shows a second exemplary embodiment of a screw compressor according to FIG. 1;

FIG. 4 shows a simplified sectional view through a center of the compressor outlet of the screw compressor according to FIG. 3;

FIG. 5 shows a third exemplary embodiment of a screw compressor according to FIG. 1;

FIG. 6 shows an exemplary embodiment of the second holder according to FIG. 6;

FIG. 7 shows a further development of the second holder according to FIG. 6; and

FIG. 8 shows different and exemplary shapes of the through-opening for the holders according to FIGS. 6 and 7.

Identical or functionally identical components are identified with the same reference symbols. In addition, not all identical or functionally identical components are provided with a reference number in the Figures.

FIG. 1 shows a refrigeration system 1 having a refrigeration circuit for a working medium M, wherein the refrigeration circuit has a compressor designed as a screw compressor 2, a first heat exchanger 3, an expansion element 4 and a second heat exchanger 5.

A working medium M is compressed in the screw compressor 2 and conducted via a line 8 to the first heat exchanger 3 and cooled and/or liquefied by heat removal. The working medium M is then expanded in an expansion element 4 and conducted to the second heat exchanger 5, also called an evaporator, wherein the heat from the first working medium M can be absorbed in the second heat exchanger 5. Finally, the working medium M is returned to the screw compressor 2 to run through the refrigeration cycle described above again.

The working medium M may be, for example, a refrigerant, such as R134a.

FIG. 2 shows a simplified sectional view of the compressor designed as a screw compressor 2 according to FIG. 1.

The screw compressor 2 comprises what is referred to in its entirety as an outer housing 10 having an inlet opening 11, an outlet opening 12 and a longitudinal axis X.

The inlet opening 11 and the outlet opening 12 are arranged on opposite sides in the longitudinal axis X. The working medium M can enter the outer housing 10 through the inlet opening 11 and the compressed and preferably gaseous working medium M can leave the outer housing 10 from an interior space 45 through the outlet opening 12.

Arranged in the outer housing 10 is a compression device 20 having a rotor 25 rotatable about a rotational axis, wherein the rotational axis is arranged parallel to the longitudinal axis X.

The compression device 20 compresses the working medium M received from the inlet opening 11 and the working medium M compressed by the compression device 20 is conducted via a compressor outlet 50 into the interior space 45 arranged in the outer housing 10.

Furthermore, the outer housing 10 may comprise a pressure bell 40, wherein the pressure bell 40 may enclose the aforementioned interior space 45.

The outer housing 10 has a bottom-side lower region 41 and an upper region 42.

Due to gravity, oil can accumulate in the lower region 41 to form an oil sump 43. The upper region 42 is arranged on opposite sides of the outer housing 10 in the direction of gravity.

The pressure bell 40 may have the outlet opening 12, wherein the outlet opening 12 is preferably arranged in the upper region 42.

The oil sump 43, in which oil separated from the compressed working medium M can collect, can form in the lower region 41 of the pressure bell 40. The oil from the oil sump 43 can be diverted to lubricate the screw compressor 2, in particular the compression device 20.

In addition, a drive motor 80, by means of which the compression device 20, more precisely the rotor 25 of the compression device 20, can be driven, may be arranged in the outer housing 10.

The drive motor 80 and the compression device 20 are located together in the pressure-resistant outer housing 10 and may be accessible via a housing cover 15 in the outer housing 10. Due to the accessible arrangement, the screw compressors 2 shown in the accompanying figures can also be referred to as semi-hermetic screw compressors 2.

The drive motor 80 in the outer housing 10 can be cooled by the working medium M. For this purpose, the working medium M can be guided past the drive motor 80 between the inlet opening 11 and the compression device 20.

The compression device 20 further comprises a rotor bore 22 that receives the rotor 25 designed as a screw rotor.

Furthermore, the compression device 20 may have a slide bore (not shown) for at least one control slide (also not shown) for output control and/or controlling the pressure ratio of the screw compressor 2.

The rotor 25 can rotate in its rotational axis relative to the rotor bore 22 and, as can be seen from FIG. 2, may be rotatably mounted on both sides of a screw body 26 in the longitudinal axis X using bearing units 27, 28.

The first bearing unit 27 is arranged on the side facing the drive motor 80 and the inlet opening 11 and the second bearing unit 28 is arranged on the side facing away from the drive motor 80 and the inlet opening 11.

In addition, the compression device 20 comprises a pressure flange 30. The pressure flange 30 is arranged on the side facing the interior space 45 and accommodates the second bearing unit 28. The pressure flange 30 forms an outlet channel 34 through which the compressed working medium M is guided from the rotor bore 22 to the compressor outlet 50.

The screw compressor 2 may have one or more compressor outlets 50, wherein in the exemplary embodiment shown in FIG. 2 only one compressor outlet 50 is shown in the drawing; see also FIG. 4.

The compressor outlet 50 protrudes freely from the compression device 20 and projects into the interior space 45. The at least one compressor outlet 50 may be tubular and may have a free end 52 through which the compressed working medium M is discharged in the outlet direction R into the interior space 45.

The compressed working medium M is discharged through the at least one compressor outlet 50 in an outlet direction R, wherein in the illustrated exemplary embodiment the outlet direction R is parallel to the longitudinal axis X.

Due to the tubular design of the compressor outlet 50, the compressor outlet 50 can also be referred to as a compressor outlet tube.

Furthermore, it can be seen from FIG. 2 that the compressor outlet 50 protrudes from a pressure flange cover 32 that closes the pressure flange 30 on the side opposite the rotor 25. The pressure flange cover 32 and the at least one compressor outlet 50 may be formed in one piece.

To separate oil from the compressed working medium M, a first demister 60 and at least one second demister 70 are arranged in the interior space 45.

In the illustrated exemplary embodiment, two second demisters 70 are arranged in the interior space 45 and are arranged spaced apart from one another in the longitudinal axis X at a third distance A3 (see FIG. 3). For better understanding, the reference number of the first second demister is “70a” and that of the second demister is “70b”.

The first second demister 70a is arranged in the longitudinal axis X at a second distance A2 from the first demister 60 (see FIG. 3) and the second second demister 70b is arranged on the side of the first second demister 70a facing away from the first demister 60 at the third distance A3 (see FIG. 3).

The second distance A2 and/or the third distance A3 are preferably at least 50 mm.

The at least one compressor outlet 50 is oriented towards the first demister 60 in the outlet direction R in order to cause the compressed working medium M to flow to or be shot at the first demister 60.

The respective demister 60, 70 has the task of separating oil droplets carried in the compressed working medium M.

When the first demister 60 is shot with the working medium M, the compressed working medium M is redirected radially with respect to the outlet direction R essentially upstream of and partially in the first demister 60. Due to their inertia, the oil droplets carried in the working medium M cannot follow the redirection of the preferably gaseous working medium M and strike the first demister 60 and can consequently be separated.

When flowing through the second demister 70, entrained oil droplets can also be separated as described above.

The separated oil can settle in the direction of gravity and can collect in the lower region 41 in the outer housing 10 to form an oil sump and drain away.

The respective demister 60, 70 is designed plate-like or disc-like in a demister plane, wherein the respective demister plane is preferably arranged transversely to the longitudinal axis X and/or outlet direction R.

The first demister 60 comprises a wire mesh 68. The wire mesh 68 may have a first thickness D1.

The first demister 60 is arranged in the outlet direction R at a first distance A1 (see FIG. 3) upstream of the at least one compressor outlet 50. For example, the first distance A1 may be approximately 5-20 mm. The small first distance A1 ensures a high shoot density of the first demister 60 by the compressed working medium M.

The at least one compressor outlet 50 is thus oriented towards the first demister 60 and can shoot the first demister 60 with the compressed working medium M.

A media-impermeable wall 62 is arranged on the side of the first demister 60 facing away from the at least one compressor outlet 50.

The wall 62 is preferably arranged in the outlet direction R immediately downstream of the demister 60 or its wire mesh 68. This has the effect that the jet of the compressed working medium M exiting from the compressor outlet 50 in the outlet direction R does not exit on the side of the first demister 60 facing away from the compressor outlet 50. The compressed and preferably gaseous working medium M is redirected radially with respect to the outlet direction R on the side facing the compressor outlet 50 upstream of or in the first demister 60. In other words, a large portion of the working medium M can flow radially outwards upstream of the first demister 60 with respect to a vector of the outlet direction R, while a remaining portion of the working medium M, together with oil droplets entrained therein, strikes and successively penetrates the first demister. The inertia of the oil droplets prevents the oil droplets from following the redirection and causes the oil droplets to strike the first demister. This can significantly improve the separation of oil from the compressed working medium M.

In the first exemplary embodiment according to FIG. 2, the outer housing 10 is concave on the side facing the compressor outlet 50. As shown in this exemplary embodiment, it may be advantageous to arrange the first demister 60, in particular in the outlet direction R and/or along the longitudinal axis X, spaced apart from the outer housing 10 or the pressure bell 40.

In the exemplary embodiment according to FIG. 2, the wall 62 on the side of the first demister 60 facing away from the compressor outlet 50 is formed by a first holder 64 that is arranged between the outer housing 10 and the first demister 60.

In the simplest case, the first holder 64 may comprise a sheet or plate on which the first demister 60 is arranged. The holder 64 can be held in a supported manner on the outer housing 10, in particular on the pressure bell 40, via spacers 65 and positions the first demister 60 in the interior space 45.

The first demister 60 may also be arranged transverse to the outlet direction R and/or longitudinal axis X, that is, in the demister plane spaced apart from the outer housing 10. Because the side surfaces are free, the compressed working medium M can escape therethrough, so that the dwell time and the distance traveled by the working medium M in the first demister 60 can be increased. It may be advantageous for the first demister 60 not to project into the oil sump 43 formed in the lower region 41.

The two second demisters 70a, 70b are arranged in the flow path between the compressor outlet 50 and the outlet opening 12. As a result, the compressed working medium M is forced through the two second demisters 70a, 70b.

The outlet opening 12 and the at least one second demister 70 are arranged against, that is, in the opposite direction to, the outlet direction R or in the longitudinal axis X spaced apart from the free end 52 of the compressor outlet 50. A second distance A2 between the first demister 60 and the first second demister 70 is preferably at least 50 mm.

The respective second demister 70a, 70b comprises a holder 74a, 74b and a wire mesh 78a, 78b arranged on the holder 74a, 74b. The respective wire mesh 78a, 78b may have a second thickness D2.

The wire mesh 78a, 78b is held in place in the interior space 45 by the holder 74a, 74b, wherein the holder 74a, 74b is arranged downstream of the wire mesh 78a, 78b, i.e., on the side facing away from the free end of the compressor outlet 50.

The at least one compressor outlet 50 projects through the at least one second demister 70.

The respective second demister 70a, 70b may be attached to the outer housing 10 and/or to the at least one compressor outlet 50 by the second holder 74a, 74b. In the illustrated exemplary embodiment, The respective second holder 74a, 74b is connected to the at least one compressor outlet 50 by means of fastening means 77a, 77b.

The first thickness D1 of the first demister 60 may be greater than the second thickness D2. This may be advantageous because the first thickness D1 may have less influence on the flow resistance in the interior space 45 between the at least one compressor outlet 50 and the outlet opening 12.

For assembly, the second demisters 70a, 70b are first fitted on the compressor outlet 50 and attached there by means of the fastening means 77a, 77b. Then the outer housing 10 or, more precisely, the pressure bell 40 can be fitted. Alternatively, the second demisters 70a, 70b may also be attached in the outer housing 10 and, together with the outer housing 10, can be fitted onto the at least one compressor outlet 50.

FIGS. 3 and 4 show a second exemplary embodiment of an inventive screw compressor 2.

The second exemplary embodiment differs from the first embodiment substantially in the arrangement of the first demister 60. For the sake of simplicity, only the differences between the two embodiments are described.

As can be seen, in particular, from the enlarged illustration according to FIG. 4, the first demister 60 is arranged directly on the outer housing 10. In this embodiment, the media-impermeable wall 62 is formed by the outer housing 10 and, more precisely, by the pressure bell 40.

According to FIG. 4, the first demister 60 extends in the demister plane transversely to the longitudinal axis X and/or the outlet direction R completely across the cross section of the interior space 45. Since both the side facing away from the compressor outlet 50 and the circumferential side surfaces of the first demister 60 abut the outer housing 10, the compressed working medium M that is shot at the first demister 60 can exit from the first demister 60 into the interior space 45 solely on the side facing the compressor outlet 50.

The first demister 60 may project into the lower region 41 and the oil sump formed there. This ensures that the separated oil reliably drips from the first demister 60 into the oil sump.

The screw compressor 2 according to the second embodiment, shown in FIGS. 3 and 4, also has two second demisters 70, wherein it is noted at this point that it is quite possible for only a single second demister 70 to be provided or even for more than two second demisters 70 to be provided.

The two second demisters 70 are arranged in parallel in the respective demister plane and in series at the third distance A3 and form two separation stages.

As FIG. 4 shows, the two parallel and spaced-apart compressor outlets 50 project through the two second demisters 70. Between the two compressor outlets 50, an actuating unit 92 may be arranged by means of which the aforementioned control slide can be moved along the longitudinal axis X or the axis of rotation of the at least one rotor 25.

The respective second holder 74 may be designed, for example, as a perforated plate or mesh plate.

As FIG. 4 shows, the two parallel and spaced-apart compressor outlets 50 project through the two second demisters 70. Between the two compressor outlets 50, an actuating unit 92 may be arranged by means of which the aforementioned control slide can be moved along the longitudinal axis X or the axis of rotation of the at least one rotor 25.

FIG. 5 shows a third exemplary embodiment of an inventive compressor designed as a screw compressor 2.

The second exemplary embodiment differs from the first embodiment substantially in the arrangement of the first demister 60. For the sake of simplicity, only the differences between the two previously explained exemplary embodiments are described.

According to FIG. 5, the first demister 60 is arranged in the demister plane parallel to the longitudinal axis X in the interior space 45.

The first demister 60 may either be held by a first holder 64 in the interior space 45 spaced apart from the outer housing 10, analogous to the first embodiment according to FIG. 1, or, as shown and analogous to the second embodiment, it may be arranged in the interior space 45 directly on the outer housing 10.

The outer housing 10 forms the wall 62 that prevents the first demister 60 from being shot through or passed through.

The outer housing 10 may be cylindrical in the region in which the first demister 60 is arranged. The first demister 60 may therefore be curved in order to lie flush against the wall 62 or the outer housing 10.

The at least one compressor outlet 50 may protrude from the pressure flange 30 and the at least one compressor outlet 50 is preferably arranged parallel to and further preferably spaced apart from the first demister 60.

The at least one compressor outlet 50 or outlet direction R is oriented towards the first demister 60 in order to shoot the first demister 60 with the compressed and preferably gaseous working medium M. The outlet direction R may be arranged perpendicular to the longitudinal axis X, for example.

As shown, the first demister 60 may be arranged in the upper region 42 of the outer housing 10.

However, it is also possible to arrange the first demister 60 between the upper region 42 and the lower region 41 or to arrange the first demister 60 in the lower region 41. The first demister 60 may project, for example, into the oil sump 43, which ensures that the separated oil reliably drips from the first demister 60 into the oil sump 43.

The screw compressor 2 according to the third embodiment may also have two second demisters 70.

The two second demisters 70 are arranged in parallel in the respective demister plane and in series at the third distance A3 and form two separation stages.

The respective second demister 70 may comprise a second holder 74 that preferably holds the wire mesh 78 in position in the interior space 45. For this purpose, as shown, the second holder 74 may be arranged in the flow path from the at least one compressor outlet 50 to the outlet opening 12 downstream of the wire mesh 78.

The demister planes of the two second demisters 70 are arranged perpendicular to the demister plane of the first demister 60.

Unlike in the previously described exemplary embodiments, the at least one compressor outlet 50 does not necessarily have to project through the at least one second demister 70, but instead the outlet opening 12 may be arranged on the side of the at least one second demister 70 facing away from the at least one compressor outlet 50, preferably in the upper region 42 on the outer housing 10 or the pressure bell 40.

FIGS. 6 and 7 show exemplary embodiments of the second holder 74, wherein, according to FIG. 6, the second holder 74 has a plurality of through-openings 75 that are round in shape.

The through-openings 75 may be arranged in rows and/or in rows offset from one another, so that the flow resistance of the second holder 74 can be reduced.

In addition, the second holder 74 according to FIG. 6 has a cut-out 76 for the respective compressor outlet 50, wherein the compressor outlet 50 can be passed through the cut-out 76. The compressor outlet 50 can be connected to the second holder 74 via connecting means, as indicated in FIG. 4.

As shown, the cut-outs 76 for the respective compressor outlet 50 and the compressor outlets 50 may be arranged mirror-symmetrical to a plane of symmetry that preferably lies in the longitudinal axis X or an axis of symmetry of the outer housing 10.

The respective cut-out 76 can be adapted to the shape of the specific compressor outlet 50, so that leakage flows between the second holder 74 and the compressor outlet 50 can be avoided. Additionally, a sealant can be used here.

A second further development of the second holder 74 can be seen in FIG. 7. The second holder 74 has a first section 71 and a second section 72, wherein the second section 72 is media-impermeable. The second section 72 can help ensure that the working medium M follows the longest possible flow path through the interior space 45, so that so-called “bypasses” to the outlet opening 12 of the outer housing 10 can be avoided.

The first section 71 extends into the lower region 41 and the second section 72 extends into the lower region 42. As shown in FIG. 6, it is also advantageous for the first section 71 and the second section 72 to be arranged on diametrical sides of the cut-outs 76.

As indicated in FIGS. 6 and 7, the cut-outs 76 for the respective compressor outlet 50 and/or compressor outlets 50 can be arbitrarily arranged, that is, as shown, asymmetrical to the plane of symmetry or the axis of symmetry.

Further possible shapes, but not all possible shapes, of the through-openings 75 are shown in FIG. 8 a-d.

FIG. 8a shows square through-openings 75.

FIG. 8b shows a triangular through-opening 75.

FIG. 8c shows a previously presented hexagonal shape of a through-opening 75 and FIG. 8d shows an oval through-opening 75.

Through-openings 75 having different shapes can be used, in particular in the first section 71.

LIST OF REFERENCE SYMBOLS

• 1 Refrigeration system
• 2 Screw compressor
• 3 First heat exchanger
• 4 Expansion element
• 5 Second heat exchanger
• 8 Lines
• 10 Outer housing
• 11 Inlet opening
• 12 Outlet opening
• 15 Housing cover
• 20 Compression device
• 22 Rotor bore
• 25 Rotor
• 26 Screw body of 25
• 27 First bearing unit
• 28 Second bearing unit
• 30 Pressure flange
• 32 Pressure flange cover
• 34 Outlet channel
• 40 Pressure bell
• 41 Lower region
• 42 Upper region
• 43 Oil sump
• 45 Interior space
• 50 Compressor outlet
• 52 Free end of 50
• 60 First demister
• 62 Wall
• 64 First holder
• 68 Wire mesh
• 70 Second demister
• 71 First section
• 72 Second section
• 75 Through-opening
• 76 Cut-out
• 78 Wire mesh
• 80 Drive motor
• 92 Actuating unit
• A1 First distance
• A2 Second distance
• A3 Third distance
• D1 First thickness of 68
• D2 Second thickness of 78
• R Outlet direction
• X Longitudinal axis