Refrigerant compressor including configuration of axial and centrifugal stages

Abstract

A refrigerant compressor may include a first compression stage arranged adjacent a first side of a shaft, a second compression stage arranged adjacent the first side of a shaft and downstream of the first compression stage, a third compression stage arranged adjacent a second side of the shaft opposite the first side, and a fourth compression stage arranged adjacent the second side of the shaft and downstream of the third compression stage. The first and third compression stages may be axial compression stages, and the second and fourth compression stages may be centrifugal compression stages.

Description

REFRIGERANT COMPRESSOR INCLUDING CONFIGURATION OF AXIAL AND CENTRIFUGAL STAGESRELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 674,348, filed July 23, 2024, the entirety of which is herein incorporated by reference.BACKGROUND

[0002] Refrigerant compressors are used to circulate refrigerant in a chiller via a refrigerant loop. Refrigerant loops are known to include a compressor, a condenser, an expansion device, and an evaporator. The compressor compresses the fluid, which then travels to the condenser, which in turn cools and condenses the fluid. The refrigerant then goes to the expansion device, which decreases the pressure of the fluid, and to the evaporator, where the fluid is vaporized, completing a refrigeration cycle.SUMMARY

[0003] In some aspects, the techniques described herein relate to a refrigerant compressor, including: a first compression stage arranged adjacent a first side of a shaft; a second compression stage arranged adjacent the first side of a shaft and downstream of the first compression stage; a third compression stage arranged adjacent a second side of the shaft opposite the first side; a fourth compression stage arranged adjacent the second side of the shaft and downstream of the third compression stage, wherein the first and third compression stages are axial compression stages, and wherein the second and fourth compression stages are centrifugal compression stages.

[0004] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein the first and third compression stages are configured such that refrigerantflows through the first and third compression stages in a direction substantially parallel to an axis of rotation of the first and third compression stages.

[0005] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein: the first compression stage includes a rotor disk and a stator, and an inner wall projects upstream of the first compression stage and is configured to direct flow toward the first compression stage.

[0006] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein the inner wall is provided by a part of a cone.

[0007] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein: the third compression stage includes a rotor disk and a stator, and a cone projects upstream of the third compression stage and is configured to direct flow toward the third compression stage.

[0008] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein the second and fourth compression stages are configured such that refrigerant enters the second and fourth compression stages in a direction substantially parallel to an axis of rotation of the second and fourth compression stages and is expelled from the second and fourth compression stages in a substantially radially outward direction.

[0009] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein the second and fourth compression stages each include a respective impeller.

[0010] In some aspects, the techniques described herein relate to a refrigerant compressor, further including a volute downstream of the second compression stage, and an interstage pipe configured to direct refrigerant from the volute toward the third compression stage.

[0011] In some aspects, the techniques described herein relate to a refrigerant compressor, further including an outlet volute downstream of the fourth compression stage, wherein the outlet volute is configured to direct refrigerant to an outlet of the refrigerant compressor.

[0012] In some aspects, the techniques described herein relate to a refrigerant compressor, further including an electric motor configured to drive the shaft, and wherein the first and second compression stages are located on a first axial side of the electric motor and the third and fourth compression stages are located on a second axial side of the electric motor opposite the first axial side.

[0013] In some aspects, the techniques described herein relate to a refrigerant system, including: a condenser; an evaporator; an expansion device; and a compressor, wherein the compressor includes: a first compression stage arranged adjacent a first side of a shaft; a second compression stage arranged adjacent the first side of a shaft and downstream of the first compression stage; a third compression stage arranged adjacent a second side of the shaft opposite the first side; a fourth compression stage arranged adjacent the second side of the shaft and downstream of the third compression stage, wherein the first and third compression stages are axial compression stages, and wherein the second and fourth compression stages are centrifugal compression stages.

[0014] In some aspects, the techniques described herein relate to a refrigerant system, wherein the first and third compression stages are configured such that refrigerant flows through the first and third compression stages in a direction substantially parallel to an axis of rotation of the first and third compression stages.

[0015] In some aspects, the techniques described herein relate to a refrigerant system, wherein: the first compression stage includes a rotor disk and a stator, and an innerwall projects upstream of the first compression stage and is configured to direct flow toward the first compression stage.

[0016] In some aspects, the techniques described herein relate to a refrigerant system, wherein: the third compression stage includes a rotor disk and a stator, and a cone projects upstream of the third compression stage and is configured to direct flow toward the third compression stage.

[0017] In some aspects, the techniques described herein relate to a refrigerant system, wherein the second and fourth compression stages are configured such that refrigerant enters the second and fourth compression stages in a direction substantially parallel to an axis of rotation of the second and fourth compression stages and is expelled from the second and fourth compression stages in a substantially radially outward direction.

[0018] In some aspects, the techniques described herein relate to a refrigerant system, wherein the second and fourth compression stages each include a respective impeller.

[0019] In some aspects, the techniques described herein relate to a refrigerant system, wherein the compressor further includes a volute downstream of the second compression stage, and an interstage pipe configured to direct refrigerant from the volute toward the third compression stage.

[0020] In some aspects, the techniques described herein relate to a method, including: pressurizing refrigerant with a compressor, wherein the compressor includes a first compression stage arranged adjacent a first side of a shaft, a second compression stage arranged adjacent the first side of a shaft and downstream of the first compression stage, a third compression stage arranged adjacent a second side of the shaft opposite the first side, a fourth compression stage arranged adjacent the second side of the shaft and downstream of the third compression stage, and wherein the first and third compression stages are axial compressionstages, and wherein the second and fourth compression stages are centrifugal compression stages.

[0021] In some aspects, the techniques described herein relate to a method, wherein, during the pressurizing step, refrigerant flows through the first and third compression stages in a direction substantially parallel to an axis of rotation of the first and third compression stages.

[0022] In some aspects, the techniques described herein relate to a method, wherein, during the pressurizing step, refrigerant enters the second and fourth compression stages in a direction substantially parallel to an axis of rotation of the second and fourth compression stages and is expelled from the second and fourth compression stages in a substantially radially outward direction.BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 schematically illustrates a refrigerant system.

[0024] Figure 2 is a perspective view of a portion of an example compressor.

[0025] Figure 3 is a side view of the portion of the example compressor.

[0026] Figure 4 is a cross-sectional view taken along line 4-4 of Figure 3.DETAILED DESCRIPTION

[0027] Figure 1 illustrates a refrigerant system 10. The refrigerant system 10 includes a main refrigerant loop, or circuit, 12 in communication with a compressor 14, a condenser 16, an evaporator 18, and an expansion device 20. This refrigerant system 10 may be used in a chiller, for example. In that example, a cooling tower may be in fluid communication with the condenser 16. While a particular example of the refrigerant system 10 is shown, this application extends to other refrigerant system configurations, includingconfigurations that do not include a chiller. Further, in Figure 1, a portion of the fluid leaving the condenser 16 may return to the compressor 14 through an economizer. An economizer is not required in all examples.

[0028] Figure 2 is a perspective view of a portion of an example compressor 14. Figure 3 is a side view of the portion of the example compressor 14. Figure 4 illustrates the same portion taken along line 4-4 of Figure 3. Some structures shown in Figures 2-4 are shown as being translucent for ease of reference.

[0029] With joint reference to Figures 2-4, the compressor 14 includes an inlet 22 and an outlet 24. While not shown in the drawings, it should be understood that the compressor 14 includes an exterior housing assembly, which includes a plurality of housing sections, that surrounds, among other components, an electric motor. The electric motor drives a shaft 26 about axis A. The electric motor may be disposed generally radially outward of the shaft 26.

[0030] In this example, the compressor 14 includes a first compression stage 28, a second compression stage 30, a third compression stage 32, and a fourth compression stage 34.

[0031] As shown in Figure 2, the first and second compression stages 28, 30 are located adjacent a first axial side of the shaft 26, while the third and fourth compression stages 32, 34 are located adjacent a second, opposite axial side of the shaft 26.

[0032] The electric motor (not shown) is configured to drive the shaft 26, which in turn drives the first, second, third, and fourth compression stages 28, 30, 32, 34. The electric motor includes a rotor and a stator, in this example. The rotor is attached to or incorporated into the shaft 26.

[0033] In this disclosure, the first and third compression stages 28, 32 are axial compression stages, and the second and fourth compression stages 30, 34 are centrifugal compression stages. In this disclosure, the first and third compression stages 28, 32 are deemed axial stages because the fluid moves (i.e., flows) substantially parallel to the axis of rotation ofthe first and third compression stages 28, 32 (i.e., the axis A) as the fluid moves through the first and third compression stages 28, 32. With respect to the second and fourth compression stages 30, 34, fluid enters in a substantially axial direction, and is then turned and expelled radially from those stages.

[0034] With reference to the first compression stage 28, it includes a rotor 36 and a stator 38 downstream of the rotor 36. The rotor 36 includes a plurality of rotor blades circumferentially spaced-apart from one another about a rotor disk. The stator 38 includes a plurality of circumferentially spaced-apart vanes. In this example an inner wall 39, which may be part of a cone, is upstream of the first compression stage 28 to direct flow toward the blades of the rotor 36.

[0035] Downstream of the stator 38, the second compression stage 30 includes an impeller 40 including an axially-oriented inlet 42 and a radially-oriented outlet 44. The impeller 40 is configured to receive axial flow and to expel flow in a radial direction into a volute 46. The volute 46 is fluidly coupled to a pipe 48, which may be called an interstage pipe, which is configured to transport fluid F from the second compression stage 30 to the third compression stage 32.

[0036] The third compression stage 32 is configured substantially similar to the first compression stage 28, with a rotor 50 and a stator 52 downstream of the rotor 50. The rotor 50 includes a plurality of rotor blades circumferentially spaced-apart from one another about a rotor disk. The stator 52 includes a plurality of circumferentially spaced-apart vanes. In this example, a cone 51 is upstream of the third compression stage 32 to direct flow toward the blades of the rotor 50. The fourth compression stage 34 is downstream of the third compression stage 32 and includes an impeller 54 including an axially-oriented inlet 56 and a radially- oriented outlet 58. The outlet 58 is fluidly coupled to a volute 60 which leads to the outlet 24.

[0037] The shaft 26, rotors 36, 50, and impellers 40, 54 are rotatable by the electric motor about an axis A to compress refrigerant F. The terms axial, radial, and circumferential in this disclosure are used relative to the axis A. The shaft 26 may be rotatably supported by a plurality of bearing assemblies, which in some examples are magnetic bearing assemblies.

[0038] Among other benefits, by providing an axial compression stage upstream of each of the centrifugal compression stages, the overall size of the compressor 14 is less than if the compressor 14 included four centrifugal compression stages.

[0039] It should be understood that terms such as “axial,” “radial,” and “circumferential” are used above with reference to the normal operational attitude of the compressor 14. Further, these terms have been used herein for purposes of explanation, and should not be considered otherwise limiting. Terms such as “generally,” “substantially,” and “about” are not intended to be boundaryless terms, and should be interpreted consistent with the way one skilled in the art would interpret those terms.

[0040] Although the different examples have the specific components shown in the illustrations, embodiments of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from one of the examples in combination with features or components from another one of the examples. In addition, the various figures accompanying this disclosure are not necessarily to scale, and some features may be exaggerated or minimized to show certain details of a particular component or arrangement.

[0041] One of ordinary skill in this art would understand that the above-described embodiments are exemplary and non-limiting. That is, modifications of this disclosure would come within the scope of the claims. Accordingly, the following claims should be studied to determine their true scope and content.

Claims

CLAIMS1. A refrigerant compressor, comprising: a first compression stage arranged adjacent a first side of a shaft; a second compression stage arranged adjacent the first side of a shaft and downstream of the first compression stage; a third compression stage arranged adjacent a second side of the shaft opposite the first side; a fourth compression stage arranged adjacent the second side of the shaft and downstream of the third compression stage, wherein the first and third compression stages are axial compression stages, and wherein the second and fourth compression stages are centrifugal compression stages.

2. The refrigerant compressor as recited in claim 1 , wherein the first and third compression stages are configured such that refrigerant flows through the first and third compression stages in a direction substantially parallel to an axis of rotation of the first and third compression stages.

3. The refrigerant compressor as recited in claim 2, wherein: the first compression stage includes a rotor disk and a stator, and an inner wall projects upstream of the first compression stage and is configured to direct flow toward the first compression stage.

4. The refrigerant compressor as recited in claim 3, wherein the inner wall is provided by a part of a cone.

5. The refrigerant compressor as recited in claim 2, wherein:the third compression stage includes a rotor disk and a stator, and a cone projects upstream of the third compression stage and is configured to direct flow toward the third compression stage.

6. The refrigerant compressor as recited in claim 1, wherein the second and fourth compression stages are configured such that refrigerant enters the second and fourth compression stages in a direction substantially parallel to an axis of rotation of the second and fourth compression stages and is expelled from the second and fourth compression stages in a substantially radially outward direction.

7. The refrigerant compressor as recited in claim 6, wherein the second and fourth compression stages each include a respective impeller.

8. The refrigerant compressor as recited in claim 6, further comprising a volute downstream of the second compression stage, and an interstage pipe configured to direct refrigerant from the volute toward the third compression stage.

9. The refrigerant compressor as recited in claim 6, further comprising an outlet volute downstream of the fourth compression stage, wherein the outlet volute is configured to direct refrigerant to an outlet of the refrigerant compressor.

10. The refrigerant compressor as recited in claim 1, further comprising an electric motor configured to drive the shaft, and wherein the first and second compression stages are located on a first axial side of the electric motor and the third and fourth compression stages are located on a second axial side of the electric motor opposite the first axial side.

11. A refrigerant system, comprising: a condenser; an evaporator; an expansion device; and a compressor, wherein the compressor includes: a first compression stage arranged adjacent a first side of a shaft; a second compression stage arranged adjacent the first side of a shaft and downstream of the first compression stage; a third compression stage arranged adjacent a second side of the shaft opposite the first side; a fourth compression stage arranged adjacent the second side of the shaft and downstream of the third compression stage, wherein the first and third compression stages are axial compression stages, and wherein the second and fourth compression stages are centrifugal compression stages.

12. The refrigerant system as recited in claim 11, wherein the first and third compression stages are configured such that refrigerant flows through the first and third compression stages in a direction substantially parallel to an axis of rotation of the first and third compression stages.

13. The refrigerant system as recited in claim 12, wherein: the first compression stage includes a rotor disk and a stator, and an inner wall projects upstream of the first compression stage and is configured to direct flow toward the first compression stage.

14. The refrigerant system as recited in claim 12, wherein: the third compression stage includes a rotor disk and a stator, and a cone projects upstream of the third compression stage and is configured to direct flow toward the third compression stage.

15. The refrigerant system as recited in claim 11, wherein the second and fourth compression stages are configured such that refrigerant enters the second and fourth compression stages in a direction substantially parallel to an axis of rotation of the second and fourth compression stages and is expelled from the second and fourth compression stages in a substantially radially outward direction.

16. The refrigerant system as recited in claim 15, wherein the second and fourth compression stages each include a respective impeller.

17. The refrigerant system as recited in claim 15, wherein the compressor further comprises a volute downstream of the second compression stage, and an interstage pipe configured to direct refrigerant from the volute toward the third compression stage.

18. A method, comprising: pressurizing refrigerant with a compressor, wherein the compressor includes a first compression stage arranged adjacent a first side of a shaft, a second compression stage arranged adjacent the first side of a shaft and downstream of the first compression stage, a third compression stage arranged adjacent a second side of the shaft opposite the first side, a fourth compression stage arranged adjacent the second side of the shaft and downstream of the third compression stage, and wherein the first and third compression stages are axial compression stages, and wherein the second and fourth compression stages are centrifugal compression stages.

19. The method as recited in claim 18, wherein, during the pressurizing step, refrigerant flows through the first and third compression stages in a direction substantially parallel to an axis of rotation of the first and third compression stages.

20. The method as recited in claim 18, wherein, during the pressurizing step, refrigerant enters the second and fourth compression stages in a direction substantially parallel to an axis of rotation of the second and fourth compression stages and is expelled from the second and fourth compression stages in a substantially radially outward direction.

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