Impeller and shaft position sensor configuration for refrigerant compressor

Abstract

The refrigerant compressor can include a first compression stage, a second compression stage downstream of the first compression stage, and a third compression stage downstream of the second compression stage. The impellers of the second and third compression stages can have a diameter that is less than the diameter of the impeller of the first compression stage. Further, the axial position sensor can be disposed adjacent to the shaft and the third compression stage.

Description

Background Technology

[0001] A refrigerant compressor is used to circulate refrigerant in a cooler via a refrigerant loop. A refrigerant loop is known to include a compressor, a condenser, an expander, and an evaporator. The compressor compresses the fluid, which then travels to the condenser, where it is cooled and condensed. The refrigerant then travels to the expander (which reduces the fluid's pressure) and finally to the evaporator, where it is evaporated, thus completing the refrigeration cycle. Summary of the Invention

[0002] In some respects, the technology described herein relates to a refrigerant compressor comprising: a first compression stage, a second compression stage downstream of the first compression stage, and a third compression stage downstream of the second compression stage, wherein the impellers of the second compression stage and the third compression stage have a smaller diameter than the impeller of the first compression stage.

[0003] In some respects, the technology described herein relates to a refrigerant compressor in which two of the first, second, and third compression stages are located on the axial side of the motor opposite to the remaining compression stage of the first, second, and third compression stages.

[0004] In some respects, the technology described herein relates to a refrigerant compressor, wherein a first compression stage is located on a first axial side of the motor, and a second and a third compression stage are located on a second axial side of the motor opposite to the first axial side.

[0005] In some respects, the technology described herein relates to a refrigerant compressor wherein a first compression stage and a second compression stage are located on a first axial side of a motor, and a third compression stage is located on a second axial side of the motor opposite to the first axial side.

[0006] In some respects, the technology described herein relates to a refrigerant compressor, further comprising interstage piping connected to an external housing assembly of the refrigerant compressor, and the interstage piping being configured to deliver refrigerant between compression stages located on opposite axial sides of the motor.

[0007] In some respects, the technology described herein relates to a refrigerant compressor in which the diameter of the impeller of the third compression stage is smaller than the diameter of the impeller of the second compression stage.

[0008] In some respects, the technology described herein relates to a refrigerant compressor in which the impellers of the second compression stage and the third compression stage have substantially the same diameter.

[0009] In some respects, the technology described herein relates to a refrigerant compressor, which also includes an axial position sensor mounted adjacent to the shaft and adjacent to the third compression stage.

[0010] In some respects, the technology described herein relates to a refrigerant compressor in which the axial position sensor is configured to generate a signal indicating the axial position between the axial position sensor and a hub that projects radially outward from the outer surface of the shaft.

[0011] In some aspects, the technology described herein relates to a refrigerant compressor comprising: a motor configured to rotate a shaft; a first compression stage, a second compression stage downstream of the first compression stage, and a third compression stage downstream of the second compression stage; and an axial position sensor of a magnetic bearing assembly disposed adjacent to the shaft and adjacent to the third compression stage.

[0012] In some respects, the technology described herein relates to a refrigerant compressor in which the axial position sensor is configured to generate a signal indicating the axial position between the axial position sensor and a hub that projects radially outward from the outer surface of the shaft.

[0013] In some respects, the technology described herein relates to a refrigerant compressor in which the impellers of the second and third compression stages have smaller diameters than the impeller of the first compression stage.

[0014] In some respects, the technology described herein relates to a refrigerant compressor in which the diameter of the impeller of the third compression stage is smaller than the diameter of the impeller of the second compression stage.

[0015] In some respects, the technology described herein relates to a refrigerant compressor in which the impellers of the second compression stage and the third compression stage have substantially the same diameter.

[0016] In some respects, the technology described herein relates to a refrigerant compressor in which two of the first, second, and third compression stages are located on the axial side of the motor opposite to the remaining compression stage of the first, second, and third compression stages.

[0017] In some aspects, the technology described herein relates to a method comprising: detecting the axial position of a shaft of a refrigerant compressor, the refrigerant compressor including a first compression stage, a second compression stage downstream of the first compression stage, and a third compression stage downstream of the second compression stage, wherein the axial position of the shaft is detected using an axial position sensor mounted adjacent to the shaft and adjacent to the third compression stage.

[0018] In some respects, the technology described herein relates to a method in which the axial position sensor is configured to generate a signal indicating the axial position between the axial position sensor and a hub that projects radially outward from the outer surface of the shaft.

[0019] In some respects, the technology described herein relates to a method, which also includes: using the refrigerant compressor to compress the refrigerant.

[0020] In some respects, the technology described herein relates to a method in which two of the first, second, and third compression stages are located on the axial side of the motor opposite to the remaining compression stage of the first, second, and third compression stages.

[0021] In some respects, the techniques described herein relate to a method in which the impellers of the second and third compression stages have smaller diameters than the impeller of the first compression stage. Attached Figure Description

[0022] Figure 1 The refrigerant system is shown schematically.

[0023] Figure 2 It is along Figure 3 The exemplary compressor is shown in the cross-sectional view taken from line 2-2.

[0024] Figure 3 This is an external view of an exemplary compressor.

[0025] Figure 4 This is a cross-sectional view of another exemplary compressor.

[0026] Figure 5 It shows the relationship with Figure 2 The impeller arrangement relative to the shaft corresponds to the embodiment.

[0027] Figure 6 It shows the relationship with Figure 4 The impeller arrangement relative to the shaft corresponds to the embodiment. Detailed Implementation

[0028] This disclosure generally relates to the construction of impellers and shaft position sensors for refrigerant compressors, and more specifically to centrifugal refrigerant compressors. In a particular example, the disclosed refrigerant compressor includes three compression stages, wherein the downstream compression stage includes an impeller smaller than that of the upstream compression stage. Furthermore, the disclosed refrigerant compressor arranges the shaft position sensor adjacent to the most downstream compression stage. The components, systems, and methods disclosed herein have been found to increase the compression ratio of the compressor, improve efficiency, increase reliability, and offer other benefits.

[0029] Figure 1 A refrigerant system 10 is shown. 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. For example, this refrigerant system 10 can be used in a cooler. In this example, a cooling tower can be in fluid communication with the condenser 16. While a specific example of a refrigerant system 10 is shown, this application extends to other refrigerant system configurations, including those that do not include a cooler. Furthermore, in Figure 1 In this process, a portion of the fluid leaving the condenser 16 can be returned to the compressor 14 via the economizer 22. The fluid from the economizer 22 is at a relatively high pressure and, in this example, is introduced into the compressor 14 at one or more locations to cool or partially compress the low-pressure fluid within the compressor 14, thereby reducing the amount of work required by the compressor 14 to achieve the desired pressure and temperature, resulting in energy savings and increased efficiency.

[0030] Figure 2 The cross-section shows along Figure 3 The exemplary compressor 14 is cut from line 2-2. Figure 3 This is an external view of an exemplary compressor 14. (Common Reference) Figure 2 and Figure 3 The compressor 14 includes an outer housing assembly 24, which comprises multiple housing sections. Among other components, the outer housing assembly 24 surrounds an electric motor 26, a first compression stage 28, a second compression stage 30, and a third compression stage 32. The compressor 14 is a centrifugal compressor and is specifically configured to compress refrigerant. Therefore, the compressor 14 is a three-stage centrifugal refrigerant compressor.

[0031] The electric motor 26 includes a stator 34 disposed radially outward of the rotor 36. The rotor 36 is connected to a shaft 38, which rotates to drive a first compression stage 28, a second compression stage 30, and a third compression stage 32. In this disclosure, each compression stage 28, 30, 32 includes a respective impeller 40, 42, 44.

[0032] like Figure 2 As shown, the first compression stage 28 is located on the first axial side of the electric motor 26, while the second compression stage 30 and the third compression stage 32 are located on the opposite second axial side of the electric motor 26.

[0033] In other embodiments, two compression stages are located on the first side of the electric motor 26, and a single compression stage is located on the second side of the electric motor 26. Specifically, as Figure 4As shown, the first compression stage 28 and the second compression stage 30 are located on the first axial side of the electric motor 26, while the third compression stage 32 is located on the opposite second axial side of the electric motor 26.

[0034] See again Figure 2 and Figure 3 The shaft 38 and impellers 40, 42, and 44 are rotatable about axis A by an electric motor 26 to compress the refrigerant F. The terms axial, radial, and circumferential in this disclosure are used relative to axis A. The shaft 38 may be supported in a rotatable manner by a plurality of bearing assemblies, which in some examples are magnetic bearing assemblies.

[0035] During operation of compressor 14, refrigerant F flows axially toward impeller 40 of the first compression stage 28 and is discharged radially outward to diffuser 46 downstream of impeller 40. Diffuser 46 is arranged radially between the outlet of impeller 40 and volute 48.

[0036] Refrigerant F discharged from the volute 48 enters the interstage conduit 50. The interstage conduit 50 is configured to transport refrigerant F from the first compression stage 28 to the second compression stage 30. (If possible...) Figure 3 The best view is that the interstage pipe 50 is attached to the outer housing assembly 24.

[0037] See again Figure 2 The refrigerant F discharged from the interstage pipe 50 is introduced back into the outer housing assembly 24 and guided to the inlet of the second compression stage 30. The second compression stage 30 discharges refrigerant F, which is redirected via the return passage 58 and guided to the third compression stage 32. Figure 4 In one embodiment, the return channel 58 is arranged between the first compression stage 28 and the second compression stage 30. (See also...) Figure 2 and Figure 3 The third compression stage 32 discharges fluid F to another volute 60, which in turn discharges fluid to the compressor discharge port 62. Figure 3 Refrigerant F flows from compressor discharge port 62 to condenser 16.

[0038] In one aspect of this disclosure, the impeller associated with the downstream compression stage is smaller than the impeller of the upstream compression stage, and in particular exhibits a smaller diameter. For example, refer to... Figure 5 , Figure 5 express Figure 2In the embodiment, the impellers 40, 42, and 44 of the first compression stages 28, 30, and 32 are arranged such that impeller 40 has a first diameter D1, impeller 42 has a second diameter D2, and impeller 44 has a third diameter D3. In this example, the first diameter D1 is larger than both the second diameter D2 and the third diameter D3. Furthermore, in this example, the third diameter D3 is smaller than the second diameter D2. In another example, diameters D2 and D3 may be equal.

[0039] Figure 6 express Figure 4 The arrangement of impellers 40, 42, and 44 in the first compression stage 28, 30, and 32 of the embodiment. (See reference...) Figure 6 Impeller 40 has a first diameter D1, impeller 42 has a second diameter D2, and impeller 44 has a third diameter D3. In this example, the first diameter D1 is larger than both the second diameter D2 and the third diameter D3. Furthermore, in this example, the third diameter D3 is smaller than the second diameter D2. In another example, diameters D2 and D3 can be equal.

[0040] Because the third compression stage 32 is downstream of the other two compression stages, the refrigerant F exhibits a relatively higher temperature within the third compression stage 32 compared to the first compression stage 28 and the second compression stage 30. Due to the relatively high temperature exposed to the third compression stage 32, the shaft 38 adjacent to the third compression stage 32 may experience thermally induced dimensional changes or thermally induced displacements. Therefore, in one aspect of this disclosure, the axial position sensor 64 of the magnetic bearing assembly is positioned adjacent to the third compression stage 32, such as... Figure 5 and Figure 6 Both refer to the axial position sensor 64, which is configured to detect the axial position of the shaft 38 by sensing the distance between the axial position sensor 64 and the hub 66 that projects radially outward from the outer surface 68 of the shaft 38. The axial position sensor 64 is configured to generate a signal indicating the axial position of the shaft 38 (including axial vibration of the shaft). This signal is then processed and used by the controller, for example, when the controller determines whether the magnetic bearing needs adjustment to better position the shaft 38 for efficient operation of the compressor 14.

[0041] It should be understood that terms such as “axial,” “radial,” and “circumferential” are used above with reference to the normal operating posture of compressor 14. Furthermore, these terms are used for illustrative purposes herein and should not be considered restrictive in any other way. Terms such as “approximately,” “substantially,” and “about” are not intended to be unbounded terms and should be interpreted in accordance with the manner in which those skilled in the art would interpret those terms.

[0042] Although the different examples have specific components shown in the figures, the embodiments of this disclosure are not limited to those specific combinations. Some components or features from one example may be used in combination with features or components from another example. Furthermore, the various figures accompanying this disclosure are not necessarily drawn to scale, and some features may be exaggerated or minimized to show certain details of a particular component or arrangement.

[0043] Those skilled in the art will understand that the above embodiments are exemplary and not restrictive. That is, modifications of this disclosure will fall within the scope of the claims. Therefore, the appended claims should be studied to determine their true scope and content.

Claims

1. A refrigerant compressor, comprising: A first compression stage, a second compression stage downstream of the first compression stage, and a third compression stage downstream of the second compression stage, wherein the impellers of the second compression stage and the third compression stage have smaller diameters than the impeller of the first compression stage.

2. The refrigerant compressor according to claim 1, wherein, Two of the first, second, and third compression stages are located on the axial side of the motor opposite to the remaining compression stage of the first, second, and third compression stages.

3. The refrigerant compressor according to claim 2, wherein, The first compression stage is located on the first axial side of the motor, and the second and third compression stages are located on the second axial side of the motor opposite to the first axial side.

4. The refrigerant compressor according to claim 2, wherein, The first compression stage and the second compression stage are located on the first axial side of the motor, and the third compression stage is located on the second axial side of the motor opposite to the first axial side.

5. The refrigerant compressor of claim 2, further comprising interstage piping connected to an external housing assembly of the refrigerant compressor, the interstage piping being configured to deliver refrigerant between compression stages located on opposite axial sides of the motor.

6. The refrigerant compressor according to claim 1, wherein, The diameter of the impeller in the third compression stage is smaller than the diameter of the impeller in the second compression stage.

7. The refrigerant compressor according to claim 1, wherein, The impellers of the second compression stage and the third compression stage have substantially the same diameter.

8. The refrigerant compressor of claim 1, further comprising an axial position sensor mounted adjacent to the shaft and adjacent to the third compression stage.

9. The refrigerant compressor according to claim 8, wherein, The axial position sensor is configured to generate a signal indicating the axial position between the axial position sensor and a hub that projects radially outward from the outer surface of the shaft.

10. A refrigerant compressor, comprising: A motor configured to rotate a shaft; A first compression stage, a second compression stage downstream of the first compression stage, and a third compression stage downstream of the second compression stage; as well as An axial position sensor for a magnetic bearing assembly, the axial position sensor being positioned adjacent to the shaft and adjacent to the third compression stage.

11. The refrigerant compressor according to claim 10, wherein, The axial position sensor is configured to generate a signal indicating the axial position between the axial position sensor and a hub that projects radially outward from the outer surface of the shaft.

12. The refrigerant compressor according to claim 10, wherein, The impellers of the second and third compression stages have smaller diameters than the impeller of the first compression stage.

13. The refrigerant compressor according to claim 12, wherein, The diameter of the impeller in the third compression stage is smaller than the diameter of the impeller in the second compression stage.

14. The refrigerant compressor according to claim 12, wherein, The impellers of the second and third compression stages have substantially the same diameter.

15. The refrigerant compressor according to claim 10, wherein, Two of the first, second, and third compression stages are located on the axial side of the motor opposite to the remaining compression stage of the first, second, and third compression stages.

16. A method comprising: The axial position of the shaft of a refrigerant compressor is detected. The refrigerant compressor includes a first compression stage, a second compression stage downstream of the first compression stage, and a third compression stage downstream of the second compression stage, wherein the axial position of the shaft is detected using an axial position sensor mounted adjacent to the shaft and adjacent to the third compression stage.

17. The method according to claim 16, wherein, The axial position sensor is configured to generate a signal indicating the axial position between the axial position sensor and a hub that projects radially outward from the outer surface of the shaft.

18. The method of claim 16, further comprising: The refrigerant compressor is used to compress the refrigerant.

19. The method of claim 16, wherein, Two of the first, second, and third compression stages are located on the axial side of the motor opposite to the remaining compression stage of the first, second, and third compression stages.

20. The method of claim 16, wherein, The impellers of the second and third compression stages have smaller diameters than the impeller of the first compression stage.

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