EP3657017B1 - Coolant compressor - Google Patents

Description

The invention relates to a refrigerant compressor, in particular for a refrigeration system, comprising an overall housing, a compressor unit arranged in the overall housing, a mechanical compressor drive unit arranged in a drive space of the overall housing for the compressor unit, a lubricant bath forming in the drive space, a lubricant bath in the overall housing separated from the drive space running inlet channel, via which the compressor unit sucks in refrigerant to be compressed.

Such refrigerant compressors are known from the prior art.

With these there is generally the problem that on the outlet side of the compressor there is an appreciable amount of lubricant thrown up, that is to say an appreciable proportion of lubricant in the compressed refrigerant, which is undesirable.

The invention is therefore based on the object of creating a refrigerant compressor in which the lubricant throw is reduced as much as possible. Please refer U.S. 2015/240798 A1 , which addresses a similar problem.

In a refrigerant compressor of the type described at the outset, this object is achieved according to the invention in that the inlet duct and the drive chamber are connected via a gas equalization duct which permits permanent gas equalization between them and which has an opening on the drive chamber side on the one hand and an opening on the inlet duct side on the other hand and whose duct length between the openings is at least corresponds to twice an equivalent channel diameter, in particular a smallest equivalent channel diameter, of the gas equalization channel.

The advantage of this solution can be seen in the fact that, on the one hand, the refrigerant compressor works optimally due to the permanent gas equalization via the gas equalization duct, since there is always gas equalization between the drive space and the inlet duct to compensate for pressure variations caused by blow-by flows or other effects, and on the other hand due to the channel length of the gas equalization channel prevents lubricant, in particular lubricant droplets, from being transported from the opening on the drive chamber side via the opening on the inlet channel side into the inlet channel and leading to an increased throw of lubricant on the outlet side of the refrigerant compressor.

It is particularly advantageous if the channel length of the gas equalization channel corresponds to at least three times, better at least four times, preferably at least five times and preferably at least six times the equivalent channel diameter.

An equivalent channel diameter of the gas equalization channel is to be understood as the diameter of a circular channel cross-section whose channel cross-sectional area corresponds to the cross-sectional area of the gas equalization channel if its cross-sectional shape deviates from a circular cross-sectional shape.

With regard to the absolute dimensions of the gas equalization channel, no further details have been given in connection with the previous explanation of the individual exemplary embodiments.

As an alternative or in addition to the solutions described above, a particularly favorable solution provides that the gas equalization channel has a channel length of at least 40 mm, better at least 60 mm, even better at least 80 mm, preferably at least 100 mm and preferably at least 110 mm.

Also with regard to the cross-sectional area of the gas equalization duct, no further details have so far been given.

As an alternative or in addition to the solutions described above, it is particularly advantageous if the gas equalization channel has a channel cross-sectional area of at least 80 mm ² , better at least 120 mm ² , even better at least 180 mm ² , preferably at least 250 mm ² and particularly preferably at least 300 mm ² since such a minimum cross-sectional area improves gas balancing, particularly due to the lower interference losses.

In order to reduce the conveyance of lubricant, in particular lubricant droplets, into the inlet channel as much as possible, it is preferably provided that the opening of the gas equalization channel on the drive chamber side is higher than the lubricant bath of the drive chamber in the direction of gravity.

Furthermore, it is particularly favorable if the opening of the gas equalization duct on the drive chamber side is arranged in the direction of gravity at least at the height of a drive shaft of the compressor drive unit.

It is particularly advantageous if the opening of the gas equalization duct on the drive space side is arranged laterally next to the compressor drive unit in the drive space.

Furthermore, it is provided that the opening of the gas equalization channel on the inlet channel side is higher in the direction of gravity than the accumulation of lubricant in the inlet channel.

Furthermore, if the inlet channel and the drive chamber are separated from one another by a separating element, in particular a partition wall of the overall housing, it is preferably provided that the gas equalization channel passes through a separating element between the drive chamber and the inlet channel.

An optimal spatial arrangement of the gas equalization duct results when the gas equalization duct extends over at least half of its duct length in or along the drive space.

The function of the gas equalization duct is particularly optimal when, during gas equalization in the gas equalization duct, a gas column located between the openings moves back and forth in the gas equalization duct without flowing through the gas equalization duct, i.e. the gas column does not penetrate the entire gas equalization duct in its entirety but instead at least a significant proportion, that is, for example at least a third of its length, remains in the gas equalization channel.

A further optimal solution provides that a gas column lying between the openings moves back and forth in the gas equalization channel during the suction gas pulsations occurring in the inlet channel in such a way that it does not cause any transport of lubricant droplets from the drive chamber into the inlet channel.

Furthermore, in the case of an optimally effective gas equalization duct, it is provided that a gas column in the gas duct between the openings only moves back and forth in the gas equalization duct during the suction gas pulsations in the inlet duct such that the maximum amount of lubricant droplets present at the opening on the drive compartment side enter the gas equalization duct, but not emerge from its inlet port side opening.

With regard to the arrangement of the gas equalization channel, no further details have been given in connection with the previous explanation of the invention.

The gas equalization channel can have any course, for example straight or curved or curved, as long as the channel length and cross-sectional area meet the conditions mentioned at the outset.

For example, the gas equalization channel could be arranged on an outside of the overall housing.

However, it is particularly favorable if the gas equalization channel is arranged in the overall housing.

The gas equalization channel can be formed by a separate part that is arranged in the overall housing and is held, for example, on a housing wall, or can be designed as a channel that is integrated into the overall housing.

Furthermore, it is advantageously provided that the gas equalization channel only connects the inlet channel running in the overall housing to the drive chamber, but not, for example, to cylinder heads seated on the overall housing or into the intake chambers of these cylinder heads. According to claim 1, a structurally particularly simple and therefore advantageous solution provides that the inlet duct passes through an engine compartment in the overall housing and that the accumulation of lubricant forms on the bottom side of the engine compartment.

In this case, it is structurally particularly advantageous if the gas equalization duct connects the drive compartment with the engine compartment. In particular, when lubricant is separated in the inlet duct, a lubricant return is provided, which supplies lubricant from a lubricant accumulation forming in the inlet duct to the drive chamber, and which in particular prevents lubricant from being transported from the drive chamber into the inlet duct.

Furthermore, with regard to lubricant recirculation, a particularly favorable solution provides that this includes a check valve, which either acts directly between the inlet channel and the drive chamber or is assigned to a channel running between the inlet channel and the drive chamber, so that the check valve allows lubricant to be transported from the drive chamber prevented from entering the intake port.

The solution described above is particularly advantageous in the case of a lubricant return, since the lubricant return works optimally through the gas equalization channel according to the invention and in particular no pressure fluctuations occur due to the lubricant return.

A particularly advantageous solution provides that the refrigerant compressor is a semi-hermetic compressor, in which the inlet channel flows through the engine compartment to cool the drive motor.

With regard to the compressor unit, no further details have been given so far either.

In principle, the compressor unit could be designed in any way.

A particularly advantageous solution, however, provides that the compressor unit is designed as a piston compressor unit.

Furthermore, no specific information was given with regard to the compressor drive unit, since its design also depends on the compressor unit.

An advantageous solution provides that the compressor drive unit includes a drive shaft, in particular a crankshaft, with eccentrics and connecting rods driven by them.

Fig. 1

eine Seitenansicht eines Ausführungsbeispiels eines erfindungsgemäßen Kältemittelverdichters;

Fig. 2

einen Schnitt längs Linie 2-2 in Fig. 1;

Fig. 3

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

Fig. 4

einen Schnitt längs Linie 4-4 in Fig. 2;

Fig. 5

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

Fig. 6

einen vergrößerten ausschnittsweisen Teilausschnitt eines einen Gasausgleichskanal umfassenden Bereichs in Fig. 5;

Fig. 7

einen Schnitt ähnlich Fig. 3 durch ein zweites Ausführungsbeispiel eines erfindungsgemäßen Kältemittelverdichters und

Fig. 8

einen Schnitt ähnlich Fig. 3 durch ein drittes Ausführungsbeispiel eines erfindungsgemäßen Kältemittelverdichters.

Show in the drawing:

1

a side view of an embodiment of a refrigerant compressor according to the invention;

2

a cut along line 2-2 in 1 ;

3

a cut along line 3-3 in 2 ;

4

a cut along line 4-4 in 2 ;

figure 5

a cut along line 5-5 in 2 ;

6

an enlarged partial section of an area comprising a gas equalization channel in figure 5 ;

7

a cut similar 3 by a second embodiment of a refrigerant compressor according to the invention and

8

a cut similar 3 by a third embodiment of a refrigerant compressor according to the invention.

a in 1 illustrated embodiment of a refrigerant compressor 10 according to the invention for a refrigeration system not shown in the drawing comprises an overall housing 12, which has a compressor section 14, in which, for example, in Figures 2 to 4 shown compressor unit 16 is arranged, which in the illustrated embodiment at least one, preferably several cylinder bores 22 with in has this movable piston 24, wherein the cylinder bores 22 are each closed, for example, by an applied valve plate 26, on which cylinder heads 28 are arranged on a side opposite the cylinder bores 22, which cylinder heads are mounted on the overall housing 12.

The individual pistons 24 of the compressor unit 16 are driven by a mechanical compressor drive unit 32, which is arranged in a drive chamber 34 of the compressor section 14 and which, for example, comprises a drive shaft 38 which can be rotated about an axis 36 and is provided with eccentrics 42, which in turn are connected by means of connecting rods 44 are coupled to the pistons 24 to move them in the cylinder bores 22.

Furthermore, a lubricant bath 48 is formed in a bottom region 46 of the drive chamber 34 that is the lowest in the direction of gravity, in which lubricant for lubricating the compressor unit 16 and the compressor drive unit 32 collects, which is conveyed via conveying elements (not shown), for example pump elements, of both the compressor unit 16 and the compressor drive unit 32 supplied for lubrication.

The overall housing 12 also includes a motor section 52 which is arranged following the compressor section 14 in the direction of the axis 36 and which encloses a motor compartment 54 in which a motor 56, in particular an electric drive motor, is arranged, the stator 62 of which is fixedly arranged in the motor section 52 , while its rotor 64 is seated on a rotor shaft 66 which preferably runs coaxially to the drive shaft 38 and is in particular integrally connected thereto and is therefore also rotatable about the axis 36 in order to drive the drive shaft 38 of the compressor drive unit 32.

In the overall housing 12 , in particular the drive compartment 34 and the motor compartment 54 are separated from one another by separating elements, for example by a partition wall 72 which preferably carries a bearing unit for the drive shaft 38 and the rotor shaft 66 .

Bearing unit 74 preferably forms a bearing sleeve 76 molded onto partition wall 72.

In the exemplary embodiment shown, an inlet connection 82 for the refrigerant to be compressed by the refrigerant compressor 10 is provided in the region of the motor section 52, via which the refrigerant enters an inlet channel, designated as a whole with 84, of the overall housing 12, which runs through the motor compartment 54 to the partition wall 72 and, following the partition 72, merges into a distributor 86 running in the compressor section 14, from which the refrigerant to be compressed then enters the inlet chambers of the cylinder heads 28, is compressed by the compressor unit 16 and is supplied to outlet chambers of the cylinder heads 28 as compressed refrigerant , from which it enters an outlet channel 94 in the housing section 14 and is guided therefrom to an outlet port 96 .

In the inlet duct 84, in particular in the area of the engine compartment 54, lubricant usually settles in such refrigerant compressors, which on the one hand results from lubricant separated from the refrigerant sucked in and on the other hand from lubricant escaping in the area of the bearing unit 74, and forms a lubricant accumulation 102 in the area of a lowest point 104 of the inlet duct 84, particularly in the engine compartment 54. This lubricant should be removed from the inlet duct 84 to reduce the lubricant throw at the outlet port 96 of the refrigerant compressor 10.

For this purpose, a lubricant return is provided in the partition wall 72 between the inlet channel 84 , in particular the engine compartment 54 , and the drive compartment 34 , which feeds lubricant from the lubricant accumulation 102 into the drive compartment 34 .

It is advantageous here if lubricant is prevented from flowing back into the inlet channel 84 . In order to achieve this, a non-return valve 106 is arranged, which only allows lubricant to pass from the lubricant accumulation 102 in the inlet channel 84 into the lubricant bath 48 .

In order to achieve this, the pressure differences occurring between the inlet channel 84 and the drive chamber 34 when the refrigerant compressor is running are used to act on the accumulation of lubricant 102 and cause it to pass through the non-return valve 106 into the lubricant bath 48 .

However, these pressure differences bring about a pumping effect acting on the accumulation of lubricant 102 in particular when, in addition to the check valve 106 , gas equalization takes place between the drive chamber 34 and the inlet channel 84 .

To compensate for any type of pressure difference between the drive chamber 34 and the inlet channel 84, for example caused by blow-by flows in the compressor unit 16 or suction gas pulsations or other effects, an in 2 , 3 and 5 illustrated gas equalization duct 112 is provided, which penetrates the partition 72 and allows the aforementioned gas equalization between the drive space 34 and the inlet duct 84, in particular the engine space 54 in this case.

The gas equalization channel 112 runs in particular in such a way that, as in 2 shown, an opening 114 of the same on the drive compartment side is located in the drive compartment 34 at a sufficient distance from a surface 118 of the lubricant bath 48 in the drive compartment 34 and an opening 116 of the gas equalization conduit 112 on the inlet conduit side is also located at a sufficient height above the accumulation of lubricant 102 in the inlet conduit 84, in particular in the engine compartment 54 .

The gas equalization channel 112 is preferably formed by a tube which is inserted into the partition wall 72 and held by it, the tube preferably extending from the partition wall 72 into the drive chamber 34 .

In order to prevent droplets of lubricant present in the drive chamber 34 from being transported through the gas equalization duct 112 during the gas equalization between the drive chamber 34 and the inlet duct 84, and thus also the engine chamber 54, from the drive chamber 34 into the inlet duct 84, in particular the engine chamber 54, the inlet duct 112 designed in such a way that it has a channel length L between the opening 114 on the drive chamber side and the opening 116 on the inlet channel side, which is at least 40 mm, even better at least 60 mm, preferably at least 80 mm and very preferably at least 100 mm or even better at least 110 mm.

Furthermore, it is preferably provided that the gas equalization channel 112 has a channel cross-sectional area Q that is at least 80 mm ² , better 120 mm ² , even better at least 180 mm ² , preferably at least 250 mm ² or very particularly advantageously at least 300 mm ² .

In particular, it is provided that the channel length L of the gas equalization channel 112 corresponds to at least twice, better at least three times, even better at least four times, preferably at least five times and preferably at least six times the equivalent channel diameter AD, with the equivalent channel diameter AD being the diameter of an im corresponds to the cross section of a circular gas equalization channel 112 or, in the case of a gas equalization channel 112 with a cross-sectional shape that deviates from a circular cross-section, corresponds to the channel diameter of a channel cross-sectional area Q that is circular in cross-section, which is the same size as the channel cross-sectional area Q' of the gas equalization channel 112 that deviates from the circular cross-sectional shape.

Such dimensions of the gas equalization channel 112 make it possible that essentially no transport of lubricant, in particular no transport of lubricant droplets, takes place through the gas equalization channel 112 from the drive chamber 34 into the inlet channel 84 , in particular the motor chamber 54 .

This is possible because the duct length L and the duct cross-sectional area Q of the gas equalization duct 112 form a gas column in the latter, which moves back and forth due to the pressure differences 84 between the opening 114 on the drive compartment side and the opening 116 on the inlet duct side, with the movements of the gas column due to the large cross-sectional area Q and the large channel length L of the gas equalization channel 112 are limited in such a way that when the gas column moves back and forth no droplets of lubricant are transported from the opening 114 on the drive chamber side in the drive chamber 34 to the opening 116 on the inlet channel side and escape from this.

Rather, when the gas column moves back and forth in the lubricant channel 112, the lubricant droplets entering through the opening 114 on the drive chamber side do not migrate as far as the opening 116 on the inlet channel side, but only into the gas equalization channel 112 and essentially out of it again to the opening 114 on the drive chamber side, or only as far as that they remain in the gas equalization channel 112 and are optionally deposited there.

In particular, the solution according to the invention allows, on the one hand, the lubricant accumulating in intake duct 84 and in particular in engine compartment 54 to be fed from lubricant pool 102 via check valve 106 to lubricant bath 48 in drive compartment 34 and, on the other hand, to prevent lubricant droplets from escaping from drive compartment 34 via gas equalization duct 112 the inlet channel 84, in particular the engine compartment 54, and thus to reduce the overall lubricant throw in such refrigerant compressors, particularly when they are operated as transcritical CO ₂ machines.

In particular, the above dimensioned and functioning gas equalization channel 112 thus allows a significant overall reduction in the lubricant throw at the outlet port 96.

In a second exemplary embodiment of a refrigerant compressor according to the invention, shown in 7 , the gas equalization duct 112' is designed to slope downwards in the direction of the drive chamber 34, so that its opening 116' on the inlet duct side is higher in the direction of gravity than the opening 114' on the drive chamber side, so that if lubricant settles in the gas equalization duct 112', this is due to under the effect of gravity from the opening 114 ′ on the drive chamber side and collects in the lubricant bath 48 .

It can thus be additionally ensured that no lubricant which settles in the gas equalization channel 112′ undesirably enters the inlet channel 84.

In a third exemplary embodiment of a refrigerant compressor according to the invention, shown in 8 , the gas equalization channel 112" is designed in such a way that it has a lowest point 122 between the opening 114" on the drive compartment side and the opening 116" on the inlet channel side, in which lubricant collects that is separated in the gas equalization channel 112".

Furthermore, the deepest point 122 is assigned a drain opening 124 that is smaller in relation to the channel cross-sectional area Q, in particular smaller by a factor of 10, which allows the lubricant collecting in the deepest point 122 to escape from the gas equalization channel 112" and - possibly also through an additional line - is fed to the lubricant bath 48 by the action of gravity.

Such a lowest point 122 in the direction of gravity can be achieved, for example, in such a way that the gas equalization duct 112" has a deflection pointing downwards in the direction of gravity, whereby this deflection is preferably located in the drive chamber 34, so that the lubricant emerging from the drip opening can reach the lubricant bath 48 without a further line is supplied.

Claims (14)

1. A refrigerant compressor, in particular for a refrigeration system, including a common housing (12), a compressor unit (16) arranged in the common housing (12), a mechanical compressor drive unit (32) for the compressor unit (16), arranged in a drive chamber (34) of the common housing (12), a lubricant bath (48) forming in the drive chamber (34), an intake duct (84) that extends in the common housing (12) in a manner separated from the drive chamber (34) and through which the compressor unit (16) draws in by suction refrigerant that is to be compressed wherein, the intake duct (84) and the drive chamber (34) are connected by way of a gas equaliser duct (112), which allows a permanent equalisation of gas between them, and which has on one side an opening (114) on the drive chamber side and on the other an opening (116) on the intake side, and of which the duct length (L) between the openings (114, 116) corresponds to at least twice an equivalent duct diameter (AD), in particular a smallest equivalent duct diameter (AD), of the gas equaliser duct (112),
   characterised in that the intake duct (84) passes through a motor compartment (54) in the common housing (12), and in that an accumulation (102) of lubricant forms on the base of the motor compartment (54), in that the opening (116 in the gas equaliser duct (112) on the intake duct side is higher up, as seen in the direction of gravity, than the accumulation (102) of lubricant in the intake duct (84).
2. A refrigerant compressor according to Claim 1, characterised in that the duct length (L) of the gas equaliser duct (112) corresponds to at least three times, or better at least four times, preferably at least five times and by preference at least six times the equivalent duct diameter (AD).
3. A refrigerant compressor according to the precharacterising clause of Claim 1 or one of the preceding claims, characterised in that the gas equaliser duct (112) has a duct length (L) of at least 40 mm, or better at least 60 mm, even better at least 80 mm, preferably at least 100 mm and by preference at least 110 mm.
4. A refrigerant compressor according to the precharacterising clause of Claim 1 or one of the preceding claims, characterised in that the gas equaliser duct (112) has a duct cross sectional surface area (Q) of at least 80 mm², or better at least 120 mm², even better at least 180 mm², by preference at least 250 mm² and by particular preference at least 300 mm².
5. A refrigerant compressor according to one of the preceding claims, characterised in that the opening (114) in the gas equaliser duct (112) on the drive chamber side is higher up, as seen in the direction of gravity, than the lubricant bath (48) in the drive chamber (34).
6. A refrigerant compressor according to one of the preceding claims, characterised in that the opening (114) in the gas equaliser duct (112) on the drive chamber side is arranged at least at the height of a drive shaft (38) of the compressor drive unit (32), as seen in the direction of gravity.
7. A refrigerant compressor according to one of the preceding claims, characterised in that the opening (114) in the gas equaliser duct (112) on the drive chamber side is arranged laterally next to the compressor drive unit (32) in the drive chamber (34).
8. A refrigerant compressor according to one of the preceding claims, characterised in that the gas equaliser duct (112) passes through a separating element (72) between the drive chamber (34) and the intake duct (84).
9. A refrigerant compressor according to one of the preceding claims, characterised in that the gas equaliser duct (112) extends within or along the drive chamber (34) over at least half of its duct length (L).
10. A refrigerant compressor according to one of the preceding claims, characterised in that, as gas is equalised in the gas equaliser duct (112), a column of gas lying between the openings (114, 116) moves to and fro in the gas equaliser duct (112) without flowing through the gas equaliser duct (112), in that in particular a column of gas lying between the openings (114, 116) moves to and fro in the gas equaliser duct (112) with the suction gas pulses that occur in the intake duct (84) such that the column of gas does not bring about any transport of lubricant droplets from the drive chamber (34) into the intake duct (84) in that in particular a column of gas lying in the gas equaliser duct (112) between the openings (114, 116) moves to and fro in the gas equaliser duct (112) with the suction gas pulses in the intake duct (84) only such that lubricant droplets at the opening (114) on the drive chamber side at most enter the gas equaliser duct (112) but do not exit from the opening (116) thereof on the intake side.
11. A refrigerant compressor according to one of the preceding claims, characterised in that the gas equaliser duct (112) connects the drive chamber (34) to the motor compartment (54).
12. A refrigerant compressor according to one of the preceding claims, characterised in that a lubricant return line (106) is provided which supplies lubricant from an accumulation (102) of lubricant forming in the intake duct (84) to the drive chamber (34), and which in particular prevents lubricant from being transported from the drive chamber (34) into the intake duct (84), in that in particular a lubricant return line (106) includes a nonreturn valve.
13. A refrigerant compressor according to one of the preceding claims, characterised in that the refrigerant compressor is a semi-hermetic compressor, in which flow of the intake duct (84) passes through the motor compartment (54) for the purpose of cooling a drive motor (56).
14. A refrigerant compressor according to one of the preceding claims, characterised in that the compressor unit (16) takes the form of a piston compressor unit, in that in particular the compressor drive unit (32) includes a drive shaft (38) having cams (42) and connecting rods (44) driven by these.

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