EP2961985B1 - Refrigerant compressor system - Google Patents

Description

The invention relates to a refrigerant compressor system comprising at least one low pressure stage and at least one high pressure stage, a suction channel leading from a suction connection for the refrigerant to the low pressure stage, an intermediate pressure channel leading from the low pressure stage to the high pressure stage, a high pressure connection connected to the high pressure stage.

Such refrigerant compressor systems are from GB 1,174,370 A , the U.S. 2,606,430 A and the EP 1 956 319 A1 known.

From the document KR 2012 0031138 a two-stage compressor device is known in which each stage has its own oil separator, the oil of which is returned to the respective stage.

The document EP 1 170 558 discloses a compressor device with compressors operated in parallel, in the first of which the oil from the oil separator is fed to the suction line.

In these, the problem has arisen that damage occurs in the low-pressure stage, in particular in the valves of the same, since there is not enough lubricant available, at least in individual operating states.

The invention is therefore based on the object of improving a refrigerant compressor system of the generic type in such a way that a sufficient supply of lubricant is always ensured for the low-pressure stage. This object is achieved according to the invention in a refrigerant compressor system of the type described at the outset in that a lubricant bath charged with the intermediate pressure in the intermediate pressure channel is provided, that a lubricant supply device removes lubricant from the lubricant reservoir and supplies it to the refrigerant that is sucked in and flows to the low pressure stage.

The advantage of the solution according to the invention is that with the lubricant supply device according to the invention there is the possibility of utilizing the pressure gradient between the intermediate pressure and the suction pressure of the refrigerant compressor system and thus of removing lubricant from the To supply the lubricant reservoir to the refrigerant drawn in from the low-pressure stage and thereby ensure sufficient lubrication, in particular of valves in the low-pressure stage.

In principle, the supply of lubricant at any point would be conceivable as long as the supply takes place to the refrigerant that is sucked in.

However, in order to supply the lubricant to the low-pressure stage as cheaply as possible, it is preferably provided that the lubricant supply device supplies the lubricant to a suction path of the low-pressure stage running in the system housing, in particular a suction channel and / or a suction chamber of the low-pressure stage, so that the lubricant can be supplied without outside the system housing components to be provided can be realized.

In particular, the suction channel or the suction chamber are also located in the system housing.

In order not to let the amount of lubricant supplied to the sucked-in refrigerant become too large, but rather to keep it within reasonable limits, it is preferably provided that the lubricant supply device comprises a metering unit which meters an amount of lubricant depending on the operating state, so that the metering unit offers the possibility to adjust the amount of lubricant depending on the operating condition.

For example, it is provided to define different operating states and / or operating state ranges and to dose the amount of lubricant with the metering unit depending on the operating state and / or operating state range.

With regard to the metering in the individual operating states, it is advantageous if the supply of lubricant by the metering unit is stopped when the compressor is at a standstill, in order to avoid an accumulation of lubricant in the suction path.

It is also advantageous if the metering unit prevents pressure equalization between the output path and the lubricant bath via the lubricant supply device during or after a compressor standstill.

This makes it possible, through the pressure difference maintained in the suction path, to return lubricant that collects in this via leakage paths, for example in the area of the respective pressure levels, to the lubricant bath and thus to avoid oil hammers, especially in the area of the working valves, when the refrigerant compressor system is restarted.

The dosing, which is dependent on the operating conditions, could take place via a separate control provided for this purpose.

Another, more advantageous solution provides that the metering unit is controlled by the compressor output, so that it is possible to use the compressor output to detect the operating states and to dose the amount of lubricant in accordance with the compressor output.

In principle, the metering unit could be designed in the most varied of ways.

For example, the metering unit could be controlled in the most varied of ways depending on the compressor output.

For example, it would be possible to control the compressor output by controlling a drive motor for the refrigerant compressor system and to electronically control the metering unit in accordance with the control of the drive motor with this controller.

A particularly simple solution, however, provides that the metering unit is controlled by a compressor shaft and metered the amount of lubricant in accordance with the speed of the compressor shaft.

With regard to the design of the metering unit itself, no further details were given.

For example, the metering unit could be designed as a slide or valve.

A particularly simple solution provides that the metering unit is designed as a metering pump.

With such a metering pump, there is a simple possibility of performing a performance-dependent metering.

In particular, the metering pump is preferably designed so that it has a speed-dependent delivery volume.

This can be implemented in a particularly simple manner if the metering pump is controlled, in particular driven, by the compressor shaft.

With regard to the metering pump itself, no further details have been given so far.

An advantageous solution provides that the metering pump is a gear pump.

With regard to the lubricant mass flow supplied to the refrigerant that is sucked in, provision is preferably made not to let it become too large, since otherwise the compressor performance and / or the stability of the Refrigerant compressor system is adversely affected because, for example, oil compression in the work rooms leads to an increased drive load.

For this reason, it is preferably provided that a lubricant mass flow supplied to the refrigerant drawn in is a maximum of 5% of the total mass flow of refrigerant and lubricant drawn in by the low-pressure stage.

With regard to the arrangement of the dosing unit, no details have been given so far.

It is preferably provided that the refrigerant compressor system has a system housing on which the metering unit is arranged.

The dosing unit is preferably arranged in a cover of the system housing, since it can be installed in the system housing in a simple manner, with the dosing unit in particular being integrated into the cover.

In order to be able to design the lubricant supply device as simply and protected as possible, a conveying channel leading from the metering unit to the lubricant reservoir is provided on the system housing, preferably on the cover, in particular in the system housing, preferably in the cover, through which there is the possibility of transferring the lubricant to convey from the lubricant reservoir to the metering unit.

It is also expedient if a conveying channel for the lubricant leading from the metering unit to the suction path is provided on the system housing, in particular in the system housing, so that simple manufacture and assembly is thereby possible.

The conveying channel can run exclusively in the system housing, for example in a cover of the same.

However, there is also the possibility that the delivery channel runs partly in the system housing and partly in a compressor component, for example in a compressor shaft.

In the latter case, the bearings for the compressor shaft can preferably also be lubricated in a targeted manner by means of the conveying channel.

In particular, for supplying the lubricant to the sucked-in refrigerant flow, it is advantageous if a nozzle for the lubricant to be supplied is assigned to the suction path.

With regard to the type of compression of the refrigerant in the refrigerant compressor system, no further details have been given in connection with the previous exemplary embodiments.

In principle, it would be conceivable to provide any type of compressor, for example scroll compressors or screw compressors.

However, the solution according to the invention has particular advantages if the refrigerant compressor comprises a reciprocating piston compressor, since a reciprocating piston compressor has suction valves which are particularly sensitive to wear.

Furthermore, it has proven to be advantageous in the formation of a low-pressure stage and a high-pressure stage if the piston compressor comprises a first cylinder bank to form the low-pressure stage and a second cylinder bank to form the high-pressure stage, so that both the low-pressure stage and the high-pressure stage can be easily separated that they are formed by different cylinder banks of a compressor.

Furthermore, no further details have been given with regard to the arrangement of the lubricant reservoir.

For example, the lubricant reservoir could be an external reservoir.

A particularly simple solution, however, provides that the lubricant reservoir is arranged in a drive space of the system housing, the drive for the low-pressure stage and the high-pressure stage being arranged in the drive space.

In particular, it is provided that the lubricant reservoir is arranged on the bottom side of the drive space.

Further features and advantages of the invention are the subject matter of the following description and the graphic representation of some exemplary embodiments.

Fig. 1

eine Seitenansicht einer erfindungsgemäßen Kältemittelverdichteranlage;

Fig. 2

eine Ansicht der Kältemittelverdichteranlage in Richtung des Pfeils A in Fig. 1;

Fig. 3

einen Schnitt längs Linie 3-3 in Fig. 2;

Fig. 4

einen Schnitt längs Linie 4-4 in Fig. 3;

Fig. 5

einen Schnitt längs Linie 5-5 in Fig. 2;

Fig. 6

einen Schnitt längs Linie 6-6 in Fig. 2;

Fig. 7

einen Schnitt längs Linie 7-7 in Fig. 6 mit ausschnittsweiser Darstellung des Zylinderkopfes, der Ventilplatte und der Zylinderbüchsen einer Zylinderbank;

Fig. 8

eine vergrößerte Darstellung des Schnitts in Fig. 6 im Bereich der Ventilplatte und des Ansaugventils;

Fig. 9

eine Draufsicht in Richtung des Pfeils A in Fig. 3;

Fig. 10

einen Schnitt längs Linie 10-10 in Fig. 9;

Fig. 11

eine Ansicht entsprechend Fig. 9 mit Draufsicht auf eine Dosierpumpe gemäß dem ersten Ausführungsbeispiel;

Fig. 12

einen Längsschnitt ähnlich Fig. 3 durch ein zweites Ausführungsbeispiel einer erfindungsgemäßen Kältemittelverdichteranlage und;

Fig. 13

einen Schnitt ähnlich Fig. 10 durch das zweite Ausführungsbeispiel der erfindungsgemäßen Kältemittelverdichteranlage.

In the drawing show:

Fig. 1

a side view of a refrigerant compressor system according to the invention;

Fig. 2

a view of the refrigerant compressor system in the direction of arrow A in Fig. 1 ;

Fig. 3

cut along line 3-3 in Fig. 2 ;

Fig. 4

cut along line 4-4 in Fig. 3 ;

Fig. 5

a cut along line 5-5 in Fig. 2 ;

Fig. 6

cut along line 6-6 in Fig. 2 ;

Fig. 7

a section along line 7-7 in Fig. 6 with partial representation of the cylinder head, the valve plate and the cylinder liners of a cylinder bank;

Fig. 8

an enlarged view of the section in Fig. 6 in the area of the valve plate and the suction valve;

Fig. 9

a plan view in the direction of arrow A in FIG Fig. 3 ;

Fig. 10

cut along line 10-10 in Fig. 9 ;

Fig. 11

a view accordingly Fig. 9 with a plan view of a metering pump according to the first embodiment;

Fig. 12

a longitudinal section similar Fig. 3 by a second embodiment of a refrigerant compressor system according to the invention and;

Fig. 13

a cut similar Fig. 10 by the second embodiment of the refrigerant compressor system according to the invention.

An embodiment of an in Fig. 1 and 2 The refrigerant compressor system 10 shown comprises a system housing designated as a whole by 12, which extends in a longitudinal direction 14.

The system housing 12 comprises a central housing body 16, which also extends in the longitudinal direction 14 and carries a first end-face cover 22 on a first end face and a second end-face cover 24 on a second end face, which, for example, still has its face facing away from the central housing body 16 Page is still provided with a flange surface 26 for mounting a converter.

The central housing body 16 comprises, as in FIG Fig. 3 shown, a drive housing section 32 of a reciprocating compressor 40, which encloses a drive space 34, wherein the drive space 34 is between the first end-side cover 22 and an intermediate wall 36 of the central housing body 16, which is located between the drive housing section 32 and a motor housing section 42 of the central housing body 16.

The motor housing section 42 for accommodating an electric motor 50 comprises a motor compartment 44, which in turn lies between the partition 36 and the second end cover 24, the motor compartment 44 also extending from the motor housing section 42 into the second end cover 24.

The electric motor, designated as a whole by 50, is seated in the motor compartment 44 and comprises a stator 52 arranged in the motor compartment 44 and a rotor 54 enclosed by the stator 52, the rotor 54 being rotatable about an axis of rotation 56.

For this purpose, the rotor 54 is seated on a compressor shaft of the reciprocating compressor 40, denoted as a whole by 60, which carries the rotor 54 with a rotor support section 62 extending in the engine compartment 44 and supports it so as to be rotatable about the axis of rotation 56. However, the compressor shaft 60 also extends into the drive space 34 and has a drive section 64 which extends through the drive space 34 and carries a plurality of eccentrics 66.

The compressor shaft 60 is in turn mounted in the system housing 12 in a bearing seat 72 provided on the partition 36 and in a bearing seat 74 provided on the first end cover 22, so that the drive section 64 with the eccentrics 66 lies between the bearing seats 72 and 74 while the rotor support section 62 extends with a free end in the engine compartment 44 starting from the bearing seat 72.

As in Fig. 3 As shown, the drive section 64 of the compressor shaft 60 with its eccentrics 66 serves to drive a plurality of cylinders 82 of the piston compressor 40, which are arranged, for example, in the form of two cylinder banks 84 and 86 in the drive housing section 32, with each of the cylinders 82 has a cylinder chamber 92 in which a piston 94 can be moved in a stroke direction 96, each cylinder chamber 92 being enclosed, for example, by a cylinder liner 98 seated in the drive section.

Each piston 94 is in turn driven by a connecting rod 102 which, on the one hand, is articulated on the piston 94 and, on the other hand, encloses one of the eccentrics 66.

The cylinder spaces 92 of each of the cylinder banks 84 and 86 are closed off by a valve plate 104 and 106, the respective valve plate 104 and 106 carrying a cylinder head 112 and 114 on its side facing away from the respective cylinder liner 98.

The cylinder head 112 is assigned to the first cylinder bank 84 and the cylinder head 114 is assigned to the second cylinder bank 86.

For example, each of the valve plates 104, 106 and each of the cylinder heads 112 and 114 overlap all of the cylinder spaces 92 of the cylinders 82 of the respective cylinder bank 84 and 86, respectively.

In the refrigerant compressor system 10 according to the invention, as in FIG Fig. 1 and 5 shown, for example, a suction shut-off valve 122 is provided, which in turn is provided with a suction connection 124, and which is mounted, for example, on the first end cover 22 and supplies refrigerant to be sucked in to a suction channel 126 provided in the first end cover 22 and the drive housing section 32, which leads from the suction shut-off valve 122 extends as far as the first cylinder bank 84, the suction channel 126 penetrating an opening 128 in the drive housing section 32, which is aligned with an opening 132 in the valve plate 104, so that the refrigerant drawn in can exit the drive housing section 32, pass through the valve plate 104 and can enter a suction chamber 134 of the cylinder head 112, as in FIG Fig. 3 , 6th and 7th shown.

In particular, the suction channel 126 and the suction chamber 134 form a suction path 130 provided in the system housing 12 for the refrigerant drawn in.

Instead of the suction shut-off valve 122, however, a simple suction line connection can also be provided, be it by means of a screw connection or a joint connection.

The suction chamber 134 is located on a side of the respective valve plate 104, 106 facing away from the cylinder chamber 92 and via suction openings 136 arranged in the respective valve plate 104, 106 for all cylinders 82 of the respective cylinder bank 84, 86, with each suction opening on a side facing the cylinder chamber 92 136 is assigned a working valve or suction valve 138, which is arranged, for example, on the valve plate 104 and which comprises a suction lamella or valve tongue 140, which in the in Fig. 7 and 8th The closed position, shown in solid lines and resting on the valve plate 104, closes the suction opening 136 and is in a position in FIG Fig. 7 and 8th The open position shown in dashed lines releases the suction opening 136, so that refrigerant can be sucked into the cylinder chamber 92 through this.

To determine the movability of the valve tongue 140, on the one hand, in its closed position, the valve plate 104 and, on the other hand, a guide recess 142 is provided in a cylinder liner collar 144 of the cylinder liner 98, in which the respective valve tongue 140 engages with a tongue tip 146 so that the tongue tip 146 in the guide recess 142 is guided in its movements between its closed and its open position.

To determine the maximally open position of the valve tongue 140, the guide recess 142 is provided with an in particular in Fig. 8 shown stop surface 148 provided, which the maximum open position, the is the maximum distance from the valve plate 104 that defines the valve tongue 140, so that the guide recess 142 forms a lift stop with the stop surface 148.

In the respective cylinder head, in Fig. 7 and 8th opposite the cylinder head 112, the suction chamber 134 is also assigned a pressure chamber 152, which is also formed in the cylinder head 112, a row of outlet valves 154, for example seated on the valve plate 104, being arranged in the pressure chamber 152, which are also capable of To release outlet openings so that compressed refrigerant can enter the pressure chamber 152 from the cylinder space 92.

The cylinders 82 of the cylinder bank 86 are also designed in the same way as the cylinders 82 of the cylinder bank 84 with the valve plate 104 and 106, the valve plate 106 and the cylinder head 114 in particular also being designed accordingly.

As in particular in Fig. 4 and 5 As shown, the refrigerant compressor system works with the two cylinder banks 84 and 86 as a two-stage compressor, that is, refrigerant sucked in by the cylinders 82 of the first cylinder bank 84 forming a low pressure stage 156 at suction pressure PS is first compressed to an intermediate pressure PZ, then into the engine compartment 44 flows in, flows through the engine compartment 44 and enters an intermediate pressure channel 162 of the drive housing section 32 so that the refrigerant at intermediate pressure PZ can enter the suction chamber 134 of the cylinder head 114 of the cylinder bank 86 and from the cylinders 82 of the second cylinder bank, which form a high pressure stage 158 86 is ultimately compressed to high pressure PH, the refrigerant under high pressure PH then being able to exit from high pressure connection 164.

In order to avoid damage to the suction valves 138, which is manifested, for example, in the fact that the valve tongues 140, in particular in the area of their tongue tips 146, show breakouts over time that are caused by striking of the valve tongues 140 and / or the tongue tip 146 on the valve plate 104 and / or the stop surfaces 148 arise at least in part, a lubricant supply device designated as a whole with 170 is provided, which consists of a lubricant bath 174 formed over a bottom area 172 of the drive chamber 34 by means of a For example, the first conveying channel 176 provided in the first end-side cover 22 as well as a filter 178 connected upstream of it removes lubricant and feeds it to a metering unit 180 via the conveying channel 176 Fig. 3 and 9 to 11 ).

The lubricant is dispensed from the metering unit 180 via an in Fig. 6 as Figures 9 to 11 The second conveying channel 182 shown in the figure and provided in the first end-side cover 22 and a filter 184 still arranged therein feeds a nozzle 186 directed into the suction channel 126, with which the lubricant can be injected into the suction channel 126 through which the sucked-in refrigerant flows, so that the in the suction channel 126 injected lubricant is entrained by the sucked in refrigerant and is supplied at least to the suction valves 138 for lubrication of the same.

The pressure difference for conveying the lubricant through the lubricant supply device 170 is already present in that a pressure corresponding to the intermediate pressure PZ is present in the drive chamber 34, which pressure is higher than the suction pressure PS, so that this pressure difference is already used to convey the lubricant from the lubricant bath 174 to the nozzle 186 is sufficient.

The metering unit 180 therefore does not necessarily have to generate a pressure difference, but rather serves primarily to achieve metering of the lubricant as a function of the output of the refrigerant compressor system, in the simplest case as a function of the speed of the compressor shaft 60.

This supplied lubricant forms, in particular in the region of the valve plate 104 and the stop surfaces 148 of the guide recesses 142, a lubricant layer through which the valve tongues 140 and of the tongue tips 146 of the valve tongues 140 on the valve plate 104 and / or on the stop surfaces 148 in order to avoid breakouts in the area of the tongue tips 146 and / or the valve tongues 140.

In order to make it as simple as possible, the dosing unit 180 could be a volume-controlling valve.

In particular, the metering unit 180 is designed as a metering pump 190 with a speed-dependent, in particular speed-proportional delivery volume, which is coupled to the compressor shaft 60 and is thus driven synchronously with the compressor shaft 60 in order to dose the lubricant injected into the suction channel 126 via the nozzle 148 proportionally to the Make speed of the compressor shaft 60.

As in Fig. 11 shown, the metering pump 190 is designed as a gear pump, which has an internally toothed outer body 192 and a corresponding externally toothed inner body 194, which is rotatable on the one hand about an axis 196 of an eccentric pin 198, the eccentric pin in turn being arranged eccentrically to the axis of rotation 56 of the compressor shaft 60 and on the compressor shaft 60 is integrally formed so that the inner body 194 of the gear pump 190 is driven directly by the compressor shaft 60.

The outer body 192 and the inner body 194 are designed relative to one another in such a way that the eccentric revolving of the eccentric pin 198 between the outer body 192 and the inner body 194 creates free spaces 202 which, as a result of the eccentric movement of the eccentric pin 198, revolve around the axis of rotation 56 of the compressor shaft 60 are moved so that lubricant supplied through an inlet pocket 204 through the conveying channel 176 enters the free spaces 202 that are formed and through the Movement of the free spaces 202 about the axis of rotation 56 is conveyed to an outlet pocket 206, which is connected to the conveying channel 182, so that the lubricant can be fed through this to the nozzle 186 directed into the suction channel 126.

The gear pump 190 is constructed in such a way that, when the eccentric pin 198 is no longer moving around the axis of rotation 56 and the inner body 194 is stationary, it blocks lubricant delivery through the lubricant supply device 170 and thus blocks the supply of lubricant to the suction channel 126 when the compressor shaft 60 is at a standstill.

This has the advantage that when the drive of the compressor shaft 60 is at a standstill and thus also when the piston 94 is at a standstill, no more lubricant can flow from the lubricant bath 174 into the suction channel 126, since the metering pump 190 prevents this.

Furthermore, the metering pump 190 also blocks a reduction in the pressure in the suction channel 126 when the compressor shaft 60 and thus the inner body 194 are at a standstill, so that lubricant still present in the suction channel 126 via other paths, for example leaks in the area of the pistons 94 of the cylinder banks 84, 86 to the lubricant bath 174 flows back.

This also has the advantage that it is possible to prevent the suction channel 126 from being flooded with lubricant when the refrigerant compressor system according to the invention is at a standstill and also to maintain the pressure in the suction channel 126 in order to prevent the lubricant in the suction channel 126 from leaking, for example in the area of the To supply cylinder banks 84, 86 to the lubricant bath 104 again and thus to avoid oil hammers when the refrigerant compressor system starts up again.

In the first exemplary embodiment of the solution according to the invention, the lubricant supply device 170 is integrated in the first end-side cover 22, so that in particular the conveying channel 176 and the conveying channel 182 lie with the nozzle 184 in the first end cover 22 and preferably also the filters 178 and 184 are also seated in the first end cover 22.

In addition, the first cover 22 advantageously also comprises a receptacle 212 for the outer body 192 of the metering pump 190, the inlet pocket 204 and the outlet pocket 206 also opening into this receptacle 212 at the end, in particular between the bearing receptacle 74 and the receptacle 212.

The outer body 192 can be inserted non-rotatably into the receptacle 212 and the inner body 194 then sits in it, which is rotatably mounted on the eccentric pin 198 in the described manner about the axis 196 and thus rotates with the eccentric pin 198 about the axis of rotation 56.

In a second exemplary embodiment of a refrigerant compressor system according to the invention, shown in FIG Fig. 12 and 13th those features that are identical to that of the first exemplary embodiment are provided with the same reference numerals, so that in this respect reference can also be made in full to the statements relating to the first exemplary embodiment.

In particular, in the same way as in the first exemplary embodiment, the lubricant bath 174 is provided in the drive space 34, from which the lubricant supply device 170 'takes lubricant, also through the conveying channel 176 provided in the first end-side cover 22.

Furthermore, the metering unit 180, formed by the metering pump 190, is also provided in the first end-side cover 22 in the same way as in the first exemplary embodiment and is designed in the same way as described in connection with the first exemplary embodiment.

However, the metering pump 190 does not convey the lubricant into a conveying channel running further in the first end-side cover 22, but into a compressor shaft channel 222, which preferably runs coaxially to the axis of rotation 56 in the compressor shaft 60 ', from the compressor shaft channel 222 in the area of the bearing seat 72' in the partition 36 ', a transverse channel 224 leads to a receiving groove 226 provided in the bearing seat 72 around the compressor shaft 60', from which a conveying channel 228 in the intermediate wall 36 'and in the drive housing section 32' extends to a nozzle 232 which enters the suction channel 126 'in the drive housing section 32' opens.

Furthermore, the compressor shaft duct 222 is provided with further transverse ducts, with, for example, a transverse duct 242 serving to lubricate a sliding bearing 244 between the compressor shaft 60 'and the bearing receptacle 74, transverse ducts 246 serving to lubricate sliding bearings 248 between the eccentrics 66 and the connecting rods 102, and transverse ducts 252 serve to lubricate sliding bearings 254 between the compressor shaft 60 'and the bearing seat 72'.

The lubricant supply device 170 'according to the invention thus serves not only to supply lubricant to the suction channel 126' in order to achieve the effects in the area of the suction valves 138 described in connection with the first embodiment, but also to provide bearings 244, 248, 254 in the area of the compressor shaft 60 'to be supplied with lubricant.

In the second exemplary embodiment, apart from the lubrication of the various plain bearings, the same advantages are achieved as described in detail in connection with the first exemplary embodiment.

Claims (15)

1. A refrigerant compressor system, comprising at least one low-pressure stage (156) and at least one high-pressure stage (158), a suction duct (126) leading from a suction connection (124) for the refrigerant to the low-pressure stage (156), an intermediate-pressure duct (162) leading from the low-pressure stage (156) to the high-pressure stage (158), a high-pressure connection (164) connected to the high-pressure stage (158), wherein there is provided a lubricant bath (174) to which the intermediate pressure (PZ) in the intermediate-pressure duct (162) is applied,
   characterized in that a lubricant feed device (170) draws lubricant from the lubricant bath representing a lubricant reservoir (174) and feeds said lubricant to the induced refrigerant flowing to the low-pressure stage (156) in an intake path (130).
2. The refrigerant compressor as claimed in claim 1, characterized in that the lubricant feed device (170) feeds the lubricant to an intake path (130) of the low-pressure stage (156) which extends in the system housing (12).
3. The refrigerant compressor system as claimed in claim 1, characterized in that the dispensing unit (180) is controlled by a compressor shaft (60).
4. The refrigerant compressor system as claimed in one of the preceding claims, characterized in that the dispensing unit (180) is designed as a dispensing pump (190).
5. The refrigerant compressor system as claimed in claim 4, characterized in that the dispensing pump (190) has a speed-dependent delivery volume.
6. The refrigerant compressor system as claimed in one of the preceding claims, characterized in that a lubricant mass flow fed to the induced refrigerant makes up at most 5% of the total mass flow of refrigerant with lubricant drawn in by the low-pressure stage (156).
7. The refrigerant compressor system as claimed in one of the preceding claims, characterized in that the refrigerant compressor system has a system housing (12) on which the dispensing unit (180) is arranged.
8. The refrigerant compressor system as claimed in claim 7, characterized in that the dispensing unit (180) is arranged on a cover (22) of the system housing (12).
9. The refrigerant compressor system as claimed in claim 8, characterized in that the dispensing unit (180) is integrated into the cover (22).
10. The refrigerant compressor system as claimed in claim 8 or 9, characterized in that a delivery duct (176) leading from the dispensing unit (180) to the lubricant reservoir (174) is provided on the system housing (12).
11. The refrigerant compressor system as claimed in one of claims 8 to 10, characterized in that a delivery duct (182, 228) for lubricant leading from the dispensing unit (180) to the intake path (130) is provided on the system housing (12).
12. The refrigerant compressor system as claimed in one of the preceding claims, characterized in that a nozzle (184, 232) for the lubricant to be fed to the intake path (130) is associated with said intake path.
13. The refrigerant compressor system as claimed in one of the preceding claims, characterized in that the refrigerant compressor system (10) comprises a piston compressor (40).
14. The refrigerant compressor system as claimed in claim 13, characterized in that the piston compressor (40) comprises a first cylinder bank (84) to form the low-pressure stage (156) and a second cylinder bank (86) to form the high-pressure stage (158).
15. The refrigerant compressor system as claimed in one of the preceding claims, characterized in that the lubricant bath (174) is arranged in a drive space (34) of the system housing (12) and in that in particular that the lubricant reservoir (174) is arranged at the bottom of the drive space (34).

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