Refrigerant compressor including configuration of toroidal and centrifugal stages

Abstract

A refrigerant compressor may include a first compression stage arranged adjacent a first side of a shaft. A refrigerant compressor may include a second compression stage arranged adjacent the first side of the shaft and downstream of the first compression stage. Further, the first compression stage may include a toroidal impeller, and the second compression stage may include a centrifugal compression stage.

Description

REFRIGERANT COMPRESSOR INCLUDING CONFIGURATION OF TOROIDAL AND CENTRIFUGAL STAGESRELATED APPLICATION(S)

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 675,302, filed July 25, 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; and a second compression stage arranged adjacent the first side of the shaft and downstream of the first compression stage, wherein the first compression stage includes a toroidal impeller, and wherein the second compression stage is a centrifugal compression stage.

[0004] In some aspects, the techniques described herein relate to a refrigerant compressor, further including: at least one additional compression stage adjacent a second side of the shaft opposite the first side.

[0005] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein: the at least one additional compression stage includes a thirdcompression stage, the at least one additional compression stage includes a fourth compression stage downstream of the third compression stage, the third compression stage includes a toroidal impeller, and the fourth compression stage is a centrifugal compression stage.

[0006] In some aspects, the techniques described herein relate to a refrigerant compressor, further including: an interstage pipe configured to transport fluid downstream of the second compression stage toward the third compression stage.

[0007] In some aspects, the techniques described herein relate to a refrigerant compressor, further including: a first volute downstream of the second compression stage, wherein the first volute is fluidly coupled to the interstage pipe.

[0008] In some aspects, the techniques described herein relate to a refrigerant compressor, further including: a second volute downstream of the fourth compression stage, wherein the second volute is fluidly coupled to an outlet of the refrigerant compressor.

[0009] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein the first compression stage is fluidly coupled to an inlet of the refrigerant compressor.

[0010] In some aspects, the techniques described herein relate to a refrigerant compressor, further including: an electric motor configured to drive a shaft, wherein the shaft drives the first, second, third, and fourth compression stages.

[0011] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein the second compression stage includes an impeller including an axially- oriented inlet and a radially-oriented outlet.

[0012] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein the fourth compression stage includes an impeller including an axially- oriented inlet and a radially-oriented outlet.

[0013] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein: the toroidal impeller includes a hub and a plurality of blades, and together with the hub, each of the blades defines a closed-loop.

[0014] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein the blades are circumferentially spaced-apart from one another about the hub.

[0015] In some aspects, the techniques described herein relate to a refrigerant compressor, wherein: the first compression stage includes a nose cone section upstream of the hub and the blades, and the nose cone section is configured to direct fluid radially outwardly toward blades.

[0016] 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; and a second compression stage arranged adjacent the first side of the shaft and downstream of the first compression stage, wherein the first compression stage includes a toroidal impeller, and wherein the second compression stage is a centrifugal 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, wherein the third compression stage includes a toroidal impeller, and wherein the fourth compression stage is a centrifugal compression stage.

[0017] In some aspects, the techniques described herein relate to a method, including: compressing refrigerant using a refrigerant compressor including a first compression stage arranged adjacent a first side of a shaft, and a second compression stage arranged adjacent the first side of the shaft and downstream of the first compression stage, wherein the first compression stage includes a toroidal impeller, and wherein the second compression stage is a centrifugal compression stage.BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 schematically illustrates a refrigerant system.

[0019] Figure 2 is a perspective view of a portion of an example compressor.

[0020] Figure 3 is a cross-sectional view taken along line 3-3 of Figure 2.

[0021] Figure 4 is a perspective view of an example toroidal compression stage.DETAILED DESCRIPTION

[0022] 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, including configurations 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.

[0023] Figure 2 is a perspective view of a portion of an example compressor 14. Figure 3 illustrates the same portion taken along line 3-3 of Figure 2. Some structures shown in Figures 2 and 3 are shown as being translucent for ease of reference. Figure 4 is a perspective view of an example toroidal compression stage.

[0024] 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, thatsurrounds, 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.

[0025] 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.

[0026] 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. While two compression stages 32, 34 are on the second side of the shaft 26 in Figure 2, this disclosure extends to arrangements without any compression stages on the second side of the shaft 26, and to arrangements with one or more compression stages on the second side of the shaft 26. If only one additional compression stage is on the second side of the shaft 26, it may include either a toroidal impeller or a centrifugal impeller.

[0027] 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.

[0028] In this disclosure, the first and third compression stages 28, 32 are toroidal 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 toroidal stages because these stages include toroidal impellers. Within the first and third compression stages 28, 32, fluid moves substantially parallel to the axis of rotation of the 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.

[0029] With reference to the first compression stage 28, it includes a toroidal impeller. In this example, and with reference to Figure 4, adjacent an upstream location, the first compression stage 28 includes a nose cone section 36 configured to direct fluid radially outwardly toward blades 38. Downstream of the nose cone section 36, the first compression stage 28 includes a plurality of blades 38 circumferentially spaced-apart from one another about a hub 40. The blades 38 are curved surfaces which, together with the hub 40, defined a closed loop. The blades 38 help to create smooth flow with minimal turbulence, in turn reducing the overall noise and increasing the efficiency of the compressor 14. The hub 40 is mounted to the shaft 26 such that rotation of the shaft 26 results in rotation of the hub 40.

[0030] Downstream of blades 38, the second compression stage 30 includes an impeller 41 including an axially-oriented inlet 42 and a radially-oriented outlet 44. The impeller 41 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.

[0031] The third compression stage 32 is configured substantially similar to the first compression stage 28, with the exception that the third compression stage 32 is facing a substantially opposite direction as the first compression stage 28. In particular, the third compression stage 32 includes a nose cone section 50, a hub 52 rotatably coupled to the shaft 26, and a plurality of circumferentially spaced-apart toroidal blades 54 mounted to the hub 52. The fourth compression stage 34 is downstream of the third compression stage 32 and includes an impeller 55 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.

[0032] The shaft 26, hubs 40, 52, and impellers 41, 55 are rotatable by the electric motor about an axis A to compress refrigerant F. The terms axial, radial, and circumferentialin 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.

[0033] 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. The compressor 14 also exhibits reduced noise.

[0034] 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.

[0035] 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.

[0036] 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; and a second compression stage arranged adjacent the first side of the shaft and downstream of the first compression stage, wherein the first compression stage includes a toroidal impeller, and wherein the second compression stage is a centrifugal compression stage.

2. The refrigerant compressor as recited in claim 1, further comprising: at least one additional compression stage adjacent a second side of the shaft opposite the first side.

3. The refrigerant compressor as recited in claim 2, wherein: the at least one additional compression stage includes a third compression stage, the at least one additional compression stage includes a fourth compression stage downstream of the third compression stage, the third compression stage includes a toroidal impeller, and the fourth compression stage is a centrifugal compression stage.

4. The refrigerant compressor as recited in claim 3, further comprising: an interstage pipe configured to transport fluid downstream of the second compression stage toward the third compression stage.

5. The refrigerant compressor as recited in claim 4, further comprising: a first volute downstream of the second compression stage,wherein the first volute is fluidly coupled to the interstage pipe.

6. The refrigerant compressor as recited in claim 4, further comprising: a second volute downstream of the fourth compression stage, wherein the second volute is fluidly coupled to an outlet of the refrigerant compressor.

7. The refrigerant compressor as recited in claim 6, wherein the first compression stage is fluidly coupled to an inlet of the refrigerant compressor.

8. The refrigerant compressor as recited in claim 3, further comprising: an electric motor configured to drive a shaft, wherein the shaft drives the first, second, third, and fourth compression stages.

9. The refrigerant compressor as recited in claim 3, wherein the second compression stage includes an impeller including an axially-oriented inlet and a radially-oriented outlet.

10. The refrigerant compressor as recited in claim 3, wherein the fourth compression stage includes an impeller including an axially-oriented inlet and a radially-oriented outlet.

11. The refrigerant compressor as recited in claim 1 , wherein: the toroidal impeller includes a hub and a plurality of blades, and together with the hub, each of the blades defines a closed-loop.

12. The refrigerant compressor as recited in claim 11, wherein the blades are circumferentially spaced-apart from one another about the hub.

13. The refrigerant compressor as recited in claim 11, wherein: the first compression stage includes a nose cone section upstream of the hub and the blades, and the nose cone section is configured to direct fluid radially outwardly toward blades.

14. A refrigerant compressor, comprising: a first compression stage arranged adjacent a first side of a shaft; and a second compression stage arranged adjacent the first side of the shaft and downstream of the first compression stage, wherein the first compression stage includes a toroidal impeller, and wherein the second compression stage is a centrifugal 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, wherein the third compression stage includes a toroidal impeller, and wherein the fourth compression stage is a centrifugal compression stage.

15. A method, comprising : compressing refrigerant using a refrigerant compressor including a first compression stage arranged adjacent a first side of a shaft, and a second compression stage arranged adjacent the first side of the shaft and downstream of the first compression stage, wherein the first compression stage includes a toroidal impeller, and wherein the second compression stage is a centrifugal compression stage.

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