Refrigerant compressor with gas equalizer duct

Abstract

A refrigerant compressor for a refrigeration system comprises a common housing, a compressor unit arranged in the common housing, a mechanical compressor drive unit for the compressor unit, arranged in a drive chamber, a lubricant bath forming in the drive chamber, an intake duct that extends in a manner separated from the drive chamber and through which the compressor unit draws in by suction refrigerant that is to be compressed. The intake duct and the drive chamber are connected by a gas equaliser duct, which allows a permanent equalisation of gas, and which has on one side an opening on the drive chamber side and on the other an opening on the intake side, and of which the duct length between the openings corresponds to at least twice an equivalent duct diameter, in particular a smallest equivalent duct diameter, of the gas equaliser duct.

Claims

1. A refrigerant compressor, in particular for a refrigeration system, including a common housing, an electrical drive motor arranged in a motor compartment in the common housing, a compressor arranged in the common housing, a mechanical compressor drive for the compressor driven by the electrical drive motor, the mechanical compressor drive arranged in a drive chamber of the common housing, a lubricant bath forming in the drive chamber, an intake duct that extends in the common housing in a manner separated from the drive chamber and through which the compressor draws in by suction refrigerant that is to be compressed, the intake duct and the drive chamber are connected by way of a gas equaliser duct, which allows a permanent equalisation of gas between them, and which has on one side an opening on a drive chamber side and on the other an opening on an intake side, and of which the duct length between the openings corresponds to at least twice an equivalent duct diameter, in particular a smallest equivalent duct diameter, of the gas equaliser duct, wherein the opening in the gas equaliser duct on the intake side is higher up, as seen in a direction of gravity, than an accumulation of lubricant in the intake duct, and wherein the intake duct passes through the motor compartment, and in that the accumulation of lubricant forms on a base of the motor compartment, and wherein the gas equaliser duct connects the drive chamber to the motor compartment.

2. The refrigerant compressor according to claim 1, wherein the duct length of the gas equaliser duct corresponds to at least three times an equivalent duct diameter.

3. The refrigerant compressor according to claim 1, wherein the gas equaliser duct has a duct length of at least 40 mm.

4. The refrigerant compressor according to claim 1, wherein the gas equaliser duct has a duct cross sectional surface area of at least 80 mm.sup.2.

5. The refrigerant compressor according to claim 1, wherein the opening in the gas equaliser duct on the drive chamber side is higher up, as seen in the direction of gravity, than the lubricant bath in the drive chamber.

6. The refrigerant compressor according to claim 1, wherein the opening in the gas equaliser duct on the drive chamber side is arranged at least at the height of a drive shaft of the compressor drive, as seen in the direction of gravity.

7. The refrigerant compressor according to claim 1, wherein the opening in the gas equaliser duct on the drive chamber side is arranged laterally next to the compressor drive in the drive chamber.

8. The refrigerant compressor according to claim 1, wherein the gas equaliser duct passes through a separating element between the drive chamber and the intake duct.

9. The refrigerant compressor according to claim 1, wherein the gas equaliser duct extends within or along the drive chamber over at least half of its duct length.

10. The refrigerant compressor according to claim 1, wherein, as gas is equalised in the gas equaliser duct, a column of gas lying between the openings moves to and fro in the gas equaliser duct without flowing through the gas equaliser duct.

11. The refrigerant compressor according to claim 1, wherein a column of gas lying between the openings moves to and fro in the gas equaliser duct with suction gas pulses that occur in the intake duct such that the column of gas does not bring about any transport of lubricant droplets from the drive chamber into the intake duct.

12. The refrigerant compressor according to claim 1, wherein a column of gas lying in the gas equaliser duct between the openings moves to and fro in the gas equaliser duct with suction gas pulses in the intake duct only such that lubricant droplets at the opening on the drive chamber side at most enter the gas equaliser duct but do not exit from the opening thereof on the intake side.

13. The refrigerant compressor according to claim 1, wherein a lubricant return line is provided which supplies lubricant from an accumulation of lubricant forming in the intake duct to the drive chamber, and which in particular prevents lubricant from being transported from the drive chamber into the intake duct.

14. The refrigerant compressor according to claim 1, wherein a lubricant return line includes a nonreturn valve.

15. The refrigerant compressor according to claim 1, wherein the refrigerant compressor is a semi-hermetic compressor, in which flow of the intake duct passes through the motor compartment for the purpose of cooling a drive motor.

16. The refrigerant compressor according to claim 1, wherein the compressor takes the form of a piston compressor.

17. The refrigerant compressor according to claim 1, wherein the compressor drive includes a drive shaft having cams and connecting rods driven by the cams.

18. The refrigerant compressor according to claim 1, wherein the duct length of the gas equaliser duct corresponds to at least 5 times an equivalent duct diameter.

19. The refrigerant compressor according to claim 1, wherein the gas equaliser duct has a duct length of at least 80 mm.

20. The refrigerant compressor according to claim 1, wherein the gas equaliser duct has a duct cross sectional surface area of at least 180 mm.sup.2.

21. A refrigerant compressor, in particular for a refrigeration system, including a common housing, an electrical drive motor arranged in a motor compartment in the common housing, a compressor arranged in the common housing, a mechanical compressor drive for the compressor driven by the electrical drive motor, the mechanical compressor drive arranged in a drive chamber of the common housing, a lubricant bath forming in the drive chamber, an intake duct that extends in the common housing in a manner separated from the drive chamber and passes through the motor compartment and through the intake duct the compressor draws in by suction refrigerant that is to be compressed, the intake duct and the drive chamber are connected by way of a gas equaliser duct, which allows a permanent equalisation of gas between them, and which has on one side an opening on a drive chamber side and on the other an opening on an intake side, and of which the duct length between the openings corresponds to at least twice an equivalent duct diameter, in particular a smallest equivalent duct diameter, of the gas equaliser duct, wherein the gas equaliser duct passes through a wall extending within the common housing between the drive chamber and the intake duct with the wall carrying a bearing unit for a drive shaft of said mechanical compressor drive.

22. A refrigerant compressor, in particular for a refrigeration system, including a common housing, an electrical drive motor arranged in a motor compartment in the common housing, a compressor arranged in the common housing, a mechanical compressor drive for the compressor driven by the electrical drive motor, the mechanical compressor drive arranged in a drive chamber of the common housing, a lubricant bath forming in the drive chamber, an intake duct that extends in the common housing in a manner separated from the drive chamber and passes through the motor compartment and through the intake duct the compressor draws in by suction refrigerant that is to be compressed, the intake duct and the drive chamber are connected by way of a gas equaliser duct, which allows a permanent equalisation of gas between them, and which has on one side an opening on a drive chamber side and on the other an opening on an intake side, and of which the duct length between the openings corresponds to at least twice an equivalent duct diameter, in particular a smallest equivalent duct diameter, of the gas equaliser duct, and wherein the gas equaliser duct passes through a wall extending within the common housing between a compressor section and a motor section of said common housing.

23. A refrigerant compressor, in particular for a refrigeration system, including a common housing, a compressor arranged in the common housing, a mechanical compressor drive for the compressor driven by the electrical drive motor, the mechanical compressor drive arranged in a drive chamber of the common housing, a lubricant bath forming in the drive chamber, an intake duct that extends in the common housing in a manner separated from the drive chamber and passes through the motor compartment and through said intake duct the compressor draws in by suction refrigerant that is to be compressed, the intake duct and the drive chamber are connected by way of a gas equaliser duct, which allows a permanent equalisation of gas between them, and which has on one side an opening on a drive chamber side and on the other an opening on an intake side, and of which the duct length between the openings corresponds to at least twice an equivalent duct diameter, in particular a smallest equivalent duct diameter, of the gas equaliser duct, and wherein the gas equaliser duct passes through a wall extending within the common housing between the drive chamber and the intake duct and wherein the gas equaliser duct is entirely below a head and valve plate for the compressor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a side view of an exemplary embodiment of a refrigerant compressor according to the invention;

(2) FIG. 2 shows a section along the line 2-2 in FIG. 1;

(3) FIG. 3 shows a section along the line 3-3 in FIG. 2;

(4) FIG. 4 shows a section along the line 4-4 in FIG. 2;

(5) FIG. 5 shows a section along the line 5-5 in FIG. 2;

(6) FIG. 6 shows an enlarged detail of part of a region in FIG. 5 that includes a gas equaliser duct;

(7) FIG. 7 shows a section similar to FIG. 3, through a second exemplary embodiment of a refrigerant compressor according to the invention; and

(8) FIG. 8 shows a section similar to FIG. 3, through a third exemplary embodiment of a refrigerant compressor according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(9) An exemplary embodiment illustrated in FIG. 1, of a refrigerant compressor 10 according to the invention for a refrigeration system (not illustrated in the drawing), includes a common housing 12, which has a compressor section 14 in which there is arranged a compressor unit 16 (illustrated for example in FIG. 2 to FIG. 4) that, in the exemplary embodiment illustrated, has at least one and preferably a plurality of cylinder bores 22 with pistons 24 movable therein, wherein the cylinder bores 22 are each closed for example by a valve plate 26 that is laid on top and on which there are arranged, on an opposite side to the cylinder bores 22, cylinder heads 28 that are mounted on the common housing 12.

(10) The individual pistons 24 of the compressor unit 16 are driven by a mechanical compressor drive unit 32 that is arranged in a drive chamber 34 of the compressor section 14 and includes for example a drive shaft 38, which is rotatable about an axis 36 and provided with cams 42 that, for their part, are coupled to the pistons 24 by means of connecting rods 44 in order to move them in the cylinder bores 22.

(11) Further, there is formed in a floor region 46 of the drive chamber 34, which is lowest down as seen in the direction of gravity, a lubricant bath 48 in which lubricant for lubricating the compressor unit 16 and the compressor drive unit 32 accumulates, wherein this lubricant is supplied both to the compressor unit 16 and the compressor drive unit 32 for the purpose of lubrication by way of conveying elements (not illustrated) such as pump elements.

(12) The common housing 12 further includes a motor section 52 that is arranged behind the compressor section 14, as seen in the direction of the axis 36, and surrounds a motor compartment 54 in which a motor 56, in particular an electrical drive motor, is arranged, of which the stator 62 is arranged fixed in the motor section 52, while the rotor 64 thereof is seated on a rotor shaft 66 that extends preferably coaxially in relation to the drive shaft 38 and in particular is connected in one piece therewith, and is thus likewise rotatable about the axis 36 in order to drive the drive shaft 38 of the compressor drive unit 32.

(13) Here, in the common housing 12 in particular the drive chamber 34 and the motor compartment 54 are separated from one another by separating elements, for example a separating wall 72 that preferably carries a bearing unit for the drive shaft 38 and the rotor shaft 66.

(14) Preferably here, the bearing unit 74 forms a bearing sleeve 76 integrally formed on the separating wall 72.

(15) In the exemplary embodiment illustrated, there is provided in the region of the motor section 52 an intake connector 82 for the refrigerant to be compressed by the refrigerant compressor 10, through which the refrigerant enters an intake duct of the common housing 12, which is designated 84 as a whole and extends through the motor compartment 54 as far as the separating wall 72 and, after the separating wall 72, merges into a distributor 86 extending in the compressor section 14, and from the distributor 86 the refrigerant to be compressed then enters intake chambers of the cylinder heads 28, is compressed by the compressor unit 16 and is supplied, in the form of compressed refrigerant, to outtake chambers of the cylinder heads 28, from which it enters an outtake duct 94 in the common housing 14 and from there is guided to an outtake connector 96.

(16) In refrigerant compressors of this kind, lubricant is conventionally deposited in the intake duct 84, in particular in the region of the motor compartment 54, wherein this lubricant results on the one hand from lubricant deposited from the refrigerant drawn in by suction and on the other from lubricant exiting in the region of the bearing unit 74, and forms an accumulation 102 of lubricant in the region of a lowest point 104 in the intake duct 84, in particular in the motor compartment 54. This lubricant has to be removed from the intake duct 84, for the purpose of reducing spurts of lubricant at the outtake connector 96 of the refrigerant compressor 10.

(17) For this purpose, a lubricant return line is provided in the separating wall 72 between the intake duct 84, in particular the motor compartment 54, and the drive chamber 34, and this lubricant return line supplies lubricant from the accumulation 102 of lubricant into the drive chamber 34.

(18) Here, it is advantageous if a backflow of lubricant into the intake duct 84 is prevented. To achieve this, there is provided a nonreturn valve 106 that only enables lubricant to be transferred from the accumulation 102 of lubricant in the intake duct 84 into the lubricant bath 48.

(19) In order to achieve this, the pressure differences occurring between the intake duct 84 and the drive chamber 34 when the refrigerant compressor is running are used in order to act on the accumulation 102 of lubricant and cause it to pass through the nonreturn valve 106 and into the lubricant bath 48.

(20) However, these pressure differences then bring about in particular a pumping effect that acts on the accumulation 102 of lubricant if, in addition to the nonreturn valve 106, there is a gas equalisation between the drive chamber 34 and the intake duct 84.

(21) In order to equalise all types of pressure differences between the drive chamber 34 and the intake duct 84, for example triggered by blow-by flow in the compressor unit 16 or suction gas pulses or other effects, a gas equaliser duct 112 illustrated in FIGS. 2, 3 and 5 is provided, and this passes through the separating wall 72 and enables the above-mentioned equalisation of gas between the drive chamber 34 and the intake duct 84, in particular in this case the motor compartment 54.

(22) In particular, the gas equaliser duct 112 extends such that—as illustrated in FIG. 2—an opening 114 therein on the drive chamber side lies in the drive chamber 34 at a sufficient spacing from a surface 118 of the lubricant bath 48 in the drive chamber 34, and an opening 116 in the gas equaliser duct 112 on the intake duct side likewise lies in the intake duct 84, in particular in the motor compartment 54, at a sufficient height above the accumulation 102 of lubricant.

(23) Preferably, the gas equaliser duct 112 is formed by a pipe that is inserted into the separating wall 72 and held thereby, wherein the pipe preferably extends from the separating wall 72 into the drive chamber 34.

(24) In order to prevent drops of lubricant in the drive chamber 34 from being transported from the drive chamber 34 and into the intake duct 84, in particular the motor compartment 54, through the gas equaliser duct 112 at the time of gas equalisation between the drive chamber 34 and the intake duct 84 and thus also the motor compartment 54, the intake duct 112 takes a form such that it has a duct length L between the opening 114 on the drive chamber side and the opening 116 on the intake duct side of at least 40 mm, or better at least 60 mm, preferably at least 80 mm and by particular preference at least 100 mm or even better at least 110 mm.

(25) Further, it is preferably provided for the gas equaliser duct 112 to have a duct cross sectional surface area Q of at least 80 mm.sup.2, or better 120 mm.sup.2, even better at least 180 mm.sup.2, preferably at least 250 mm.sup.2 or most particularly advantageously at least 300 mm.sup.2.

(26) In particular, it is provided for the duct length L of the gas equaliser duct 112 to correspond to at least twice, or better at least three times, or even better at least four times, preferably at least five times and by preference at least six times the equivalent duct diameter AD, wherein the equivalent duct diameter AD corresponds to the diameter of a gas equaliser duct 112 that is circular in cross section or, in the case of a gas equaliser duct 112 having a cross sectional shape differing from a circular cross sectional shape, corresponds to the duct diameter of a duct cross sectional surface area Q that is circular in cross section and is of the same size as the duct cross sectional surface area Q′ of the gas equaliser duct 112 differing from the circular cross sectional shape.

(27) Dimensions of this kind for the gas equaliser duct 112 make it possible for substantially no lubricant transport, in particular no transport of droplets of lubricant, to take place through the gas equaliser duct 112 from the drive chamber 34 and into the intake duct 84, in particular the motor compartment 54.

(28) This is possible because, as a result of the duct length L and the duct cross sectional surface area Q of the gas equaliser duct 112, there is formed in the gas equaliser duct 112 a column of gas that moves to and fro as a result of the pressure differences 84 between the opening 114 on the drive chamber side and the opening 116 on the intake duct side, wherein movements of the column of gas are limited as a result of the large cross sectional surface area Q and the large duct length L of the gas equaliser duct 112 such that, during the to-and-fro movement of the column of gas, no lubricant droplets are transported from the opening 114 on the drive chamber side, in the drive chamber 34, to the opening 116 on the intake duct side and no lubricant droplets exit therefrom.

(29) Rather, during the to-and-fro movement of the column of gas in the lubricant duct 112, the lubricant droplets entering through the opening 114 on the drive chamber side do not migrate to the opening 116 on the intake duct side but only into the gas equaliser duct 112 and substantially out of it again at the opening 114 on the drive chamber side, or only migrate far enough to remain in the gas equaliser duct 112 and if appropriate settle there.

(30) In particular, the solution according to the invention on the one hand enables the lubricant accumulating in the intake duct 84 and in particular in the motor compartment 54 to be supplied from the accumulation 102 of lubricant, by way of the nonreturn valve 106 to the lubricant bath 48 in the drive chamber 34, and on the other enables the possibility of transporting lubricant droplets through the gas equaliser duct 112 from the drive chamber 34 and into the intake duct 84, in particular the motor compartment 54, to be prevented, and thus overall enables the spurting of lubricant in refrigerant compressors of this kind to be reduced, in particular if these are operated as transcritical CO.sub.2 machines.

(31) In particular, the gas equaliser duct 112 having the above dimensions and functioning thus enables the spurting of lubricant at the outtake connector 96 to be significantly reduced.

(32) In a second exemplary embodiment of a refrigerant compressor according to the invention, illustrated in FIG. 7, the gas equaliser duct 112′ takes a form that descends in the direction of the drive chamber 34 such that the opening 116′ thereof on the intake duct side is higher up, as seen in the direction of gravity, than the opening 114′ on the drive chamber side, with the result that, in the event that lubricant is deposited in the gas equaliser duct 112′, it exits from the opening 114′ on the drive chamber side under the action of gravity and accumulates in the lubricant bath 48.

(33) In this way, it is additionally ensured that no lubricant deposited in the gas equaliser duct 112′ undesirably enters the intake duct 84.

(34) In a third exemplary embodiment of a refrigerant compressor according to the invention, illustrated in FIG. 8, the gas equaliser duct 112″ takes a form such that, between the opening 114″ on the drive chamber side and the opening 116″ on the intake duct side, it has a lowest point 122 at which lubricant that is settled in the gas equaliser duct 112″ accumulates.

(35) Further, associated with the lowest point 122 there is also a drip opening 124 that is smaller by comparison with the duct cross sectional surface area Q, in particular by a factor of 10, and enables the lubricant accumulating at the lowest point 122 to exit from the gas equaliser duct 112″ and—where appropriate through an additional line—to be supplied to the lubricant bath 48 under the action of gravity.

(36) A lowest point 122, as seen in the direction of gravity, of this kind can be achieved for example in that the gas equaliser duct 112″ has a downwardly pointing deflection, as seen in the direction of gravity, wherein this deflection is preferably located in the drive chamber 34, such that the lubricant exiting from the drip opening is supplied to the lubricant bath 48 without a further line.