Refrigerant compressor with radial-axial-radial arranged impeller
By introducing an axial stage and a U-shaped return channel into the refrigerant compressor, the fluid flow path is optimized, solving the problems of insufficient efficiency and pressure ratio in the prior art and realizing efficient high-pressure applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DANFOSS AS
- Filing Date
- 2024-11-26
- Publication Date
- 2026-06-02
AI Technical Summary
Existing refrigerant compressors are inefficient and have insufficient pressure ratios in high-pressure applications, and it is difficult to improve their performance without increasing machine size.
By introducing an axial stage into the refrigerant compressor, combined with a U-shaped return channel and a volute structure, the fluid flow path is optimized, enabling the fluid to undergo multi-stage compression between radial and axial stages.
It improves the efficiency and pressure ratio of the refrigerant compressor while essentially not increasing the physical size of the machine, making it suitable for high-pressure applications.
Smart Images
Figure CN122139078A_ABST
Abstract
Description
Cross-references to related applications
[0001] This application claims priority to U.S. Provisional Application No. 63 / 606,770, filed on December 6, 2023. Background Technology
[0002] A refrigerant compressor is used to circulate refrigerant within a refrigeration machine via a refrigerant loop. The refrigerant loop is known to include a condenser, an expander, and an evaporator. The compressor compresses the fluid, which then flows to the condenser, where it is cooled and condensed. The refrigerant then flows to the expander, which reduces the fluid's pressure, and subsequently to the evaporator, where it is vaporized, thus completing the refrigeration cycle.
[0003] Many refrigerant compressors are centrifugal compressors and have an electric motor that drives at least one impeller to compress the refrigerant. Fluid flows into the impeller in an axial direction and exits radially from the impeller. The fluid is then directed downstream for use in the refrigeration system. Summary of the Invention
[0004] In some aspects, the technology described herein relates to a refrigerant compressor including a shaft rotatable about an axis. A first radial stage includes a first radial impeller coupled to the shaft. An axial stage fluidly downstream of the first radial stage includes an axial stage impeller coupled to the shaft. A second radial stage fluidly downstream of the axial stage includes a second radial impeller coupled to the shaft.
[0005] In some respects, the technology described herein relates to a refrigerant compressor comprising a U-shaped return channel fluidly located between a first radial stage and an axial stage.
[0006] In an implementation, the axial stage includes an axial stage stator.
[0007] In one embodiment, the first radial stage is configured such that the refrigerant flows parallel to the axis when entering the first radial impeller and flows radially outward when leaving the first radial impeller.
[0008] In some respects, the technology described herein relates to a refrigerant compressor that includes a return passage fluidly located downstream of a first radial impeller.
[0009] In this implementation, the return channel is curved to smoothly redirect the refrigerant radially inward and axially toward the axial stage.
[0010] In one embodiment, the axial stage is configured such that refrigerant enters the axial stage impeller in a first direction and exits the axial stage stator in a second direction, and the first and second directions are within 30 degrees parallel to the axis.
[0011] In some respects, the technology described herein relates to a refrigerant compressor in which the first and second directions are within 10 degrees parallel to the axis.
[0012] In some respects, the technology described herein relates to a refrigerant compressor including a volute and a second radial stage configured such that a second radial impeller receives refrigerant flowing in a second direction and guides the refrigerant radially outward to the volute.
[0013] In some respects, the technology described herein relates to a refrigerant compressor comprising a housing, wherein a first radial stage, an axial stage, and a second radial stage are disposed within the housing.
[0014] In some aspects, the technology described herein relates to a refrigerant compressor including a shaft rotatable about an axis, a return passage, and a volute. A first radial stage includes a first radial impeller coupled to the shaft, the first radial impeller being configured to receive refrigerant flowing in a first direction and to direct refrigerant to the return passage in a second direction, and the return passage being configured to direct refrigerant in a third direction. An axial stage fluidly downstream of the first radial stage includes an axial stage impeller coupled to the shaft, and the axial stage is configured to receive refrigerant flowing in a fourth direction and to discharge refrigerant flowing in a fifth direction. A second radial stage fluidly downstream of the axial stage includes a second radial impeller coupled to the shaft and configured to direct refrigerant to the volute in a sixth direction. The first, fourth, and fifth directions are within 30 degrees parallel to the axis, and the second, third, and sixth directions are within 30 degrees perpendicular to the axis.
[0015] In the implementation, the first direction, the fourth direction, and the fifth direction are within 10 degrees parallel to the axis.
[0016] In the implementation, the second direction, the third direction, and the sixth direction are within 10 degrees perpendicular to the axis.
[0017] In the implementation, the second direction is substantially radially outward, and the third direction is substantially radially inward.
[0018] In some respects, the technology described herein relates to a refrigerant compressor comprising a housing, wherein a first radial stage, an axial stage, and a second radial stage are disposed within the housing.
[0019] In this implementation, the return channel is U-shaped. Attached Figure Description
[0020] Figure 1 The refrigerant system is illustrated schematically.
[0021] Figure 2 An example compressor is shown.
[0022] Figure 3 Showing Figure 2 A side view of an example compressor.
[0023] Figure 4 The diagram illustrates the flow of refrigerant. Figure 2 and Figure 3 Example compressor. Detailed Implementation
[0024] This disclosure generally relates to refrigerant compressors, and more specifically to compressors with an axial stage between two radial stages. The systems and methods disclosed herein have been found to improve efficiency and pressure ratios without substantially increasing the size of the compressor.
[0025] Figure 1 A refrigerant system 10 is illustrated. The refrigerant system 10 includes a main refrigerant loop or circuit 12 connected to a compressor 14, a condenser 16, an evaporator 18, and an expansion unit 20. For example, this refrigerant system 10 can be used in a refrigeration unit. In this example, a cooling tower may be in fluid communication with the condenser 16. While a specific example of the refrigerant system 10 is shown, this application extends to other refrigerant system configurations, including those that do not include a refrigeration unit. For example, the main refrigerant loop 12 may include an economizer downstream of the condenser 16 and upstream of the expansion unit 20.
[0026] Figure 2 An example refrigerant compressor 14 according to this disclosure is shown. The example compressor 14 includes a first radial stage 22, an axial stage 24, and a second radial stage 26. The axial stage 24 is located downstream of the first radial stage 22 relative to the refrigerant flowing through the compressor 14. The second radial stage 26 is located downstream of the axial stage 24 relative to the refrigerant flowing through the compressor 14. The axial stage 24 is axially positioned between the first radial stage 22 and the second radial stage 26. In some examples, the axial stage 24 may be spaced apart from the second radial stage 26.
[0027] The first radial stage 22 includes an impeller 28, the axial stage 24 includes an impeller 30, and the second radial stage 26 includes an impeller 32. A volute 33 surrounds the second radial stage 26. The described stages 22, 24, and 26 are each housed within the same housing 35 of the compressor 14. The housing 35 may be provided by one or more structures. In some examples, as shown, the compressor 14 has a single volute 33.
[0028] When the refrigerant flows through impellers 28, 30, and 32, the blades of impellers 28, 30, and 32 force the flow velocity to increase, thus increasing the flow kinetic energy and consequently increasing the pressure.
[0029] Figure 3 A side view of an example compressor 14 is shown. In some examples, as shown, impellers 28, 30, and 32 are each coupled to shaft 34 via a motor (not shown), which is rotatable about axis A. Axial stage 24 includes an axial stage stator 36, which is axially positioned relative to axis A between impellers 30 and 32. Example stator 36 is located downstream of impeller 30 and upstream of impeller 32. In some examples shown, impeller 30 and stator 36 may be substantially axially centered on shaft 34. In some examples, axial stage 24 may include more than one impeller or stator.
[0030] Figure 4 This schematically demonstrates the refrigerant passing through... Figure 2 and Figure 3 The flow path of the example compressor 14 is shown below. The refrigerant flows from left to right parallel to axis A in direction F1 as shown, then through impeller 28, where it is radially directed outward in direction F2 to return passage 40. In some examples, the flow direction F1 is within 30 degrees parallel to axis A. In some examples, the flow direction F1 is within 10 degrees parallel to axis A. Return passage 40 is curved to smoothly redirect the refrigerant radially inward in direction F3, which in some examples is substantially opposite to direction F2. Return passage 40 also directs the refrigerant axially toward the axial stage as it turns radially. In some examples, as shown, return passage 40 is U-shaped.
[0031] After exiting the return channel 40, the refrigerant is directed to flow substantially parallel to axis A in direction F4, then through impeller 30 and stator 36, exiting stator 36 in direction F5. The refrigerant exits impeller 30 and then flows through stator 36. In some examples, the flow directions F4 and F5 are within 30 degrees parallel to axis A. In some examples, the flow directions F4 and F5 are within 10 degrees parallel to axis A. After exiting stator 36, the refrigerant flows to and through impeller 32, where it is radially outward in direction F6 to volute 33.
[0032] In some examples, as shown, direction F1 is substantially the same as directions F4 and / or F5 (± 30 degrees). In some examples, as shown, direction F2 is substantially the same as direction F6 (± 30 degrees). In some examples, as shown, direction F2 is substantially opposite to direction F3. In some examples, as shown, a continuous path including each direction F1, F2, F3, F4, F5, F6 is within the housing 35. In some examples, as shown, directions F2, F3, F6 are perpendicular to axis A. In some examples, directions F2, F3, F6 are within 30 degrees perpendicular to axis A. In some examples, directions F2, F3, F6 are within 10 degrees perpendicular to axis A. The flow through the upper portion of the cross-section of compressor 14 is schematically shown, but compressor 14 substantially includes the same flow symmetrical about its central longitudinal axis A.
[0033] Compared to existing two-stage radial compressors, the applicant has found that adding an axial stage increases the total machine pressure without significantly increasing machine size. This increased machine pressure enables the machine to be used in applications requiring high pressure.
[0034] A refrigerant compressor according to one or more of the disclosed examples may be considered to include a shaft rotatable about an axis. A first radial stage includes a first radial impeller coupled to the shaft. An axial stage fluidly downstream of the first radial stage includes an axial stage impeller coupled to the shaft. A second radial stage fluidly downstream of the axial stage includes a second radial impeller coupled to the shaft.
[0035] In one embodiment, the U-shaped return channel may be fluidly located between the first radial stage and the axial stage. In another embodiment, the axial stage includes an axial stage stator. In yet another embodiment, the first radial stage is configured such that the refrigerant flows parallel to the axis as it enters the first radial impeller and flows radially outward as it exits the first radial impeller.
[0036] In one embodiment, the return channel is curved to smoothly redirect the refrigerant radially inward and axially toward the axial stage. In another embodiment, the axial stage is configured such that the refrigerant enters the axial stage impeller in a first direction and exits the axial stage stator in a second direction, with the first and second directions within 30 degrees parallel to the axis. In yet another embodiment, the first and second directions are within 10 degrees parallel to the axis.
[0037] In one embodiment, a volute may be included, and the second radial stage is configured such that the second radial impeller receives refrigerant flowing in a second direction and guides the refrigerant radially outward to the volute.
[0038] In this embodiment, the first radial stage, the axial stage, and the second radial stage are disposed within a common housing.
[0039] A refrigerant compressor according to one or more of the disclosed examples may be considered to include a shaft rotatable about an axis, a return passage, and a volute. A first radial stage includes a first radial impeller coupled to the shaft, the first radial impeller being configured to receive refrigerant flowing in a first direction and to guide refrigerant to the return passage in a second direction, and the return passage being configured to guide refrigerant in a third direction. An axial stage fluidly located downstream of the first radial stage includes an axial stage impeller coupled to the shaft, and the axial stage is configured to receive refrigerant flowing in a fourth direction and to discharge refrigerant flowing in a fifth direction. A second radial stage fluidly located downstream of the axial stage includes a second radial impeller coupled to the shaft and configured to guide refrigerant to the volute in a sixth direction. The first, fourth, and fifth directions are within 30 degrees parallel to the axis, and the second, third, and sixth directions are within 30 degrees perpendicular to the axis.
[0040] In one embodiment, the first, fourth, and fifth directions are within 10 degrees parallel to the axis. In another embodiment, the second, third, and sixth directions are within 10 degrees perpendicular to the axis. In yet another embodiment, the second direction is substantially radially outward, and the third direction is substantially radially inward. In yet another embodiment, the first radial stage, the axial stage, and the second radial stage are disposed within a common housing. In yet another embodiment, the return channel is U-shaped.
[0041] Although different examples are shown with specific components, the examples in this disclosure are not limited to those specific combinations. Some components or features from any embodiment may be used in combination with features or components from any other embodiment.
[0042] The foregoing description should be interpreted illustratively and not in any restrictive sense. Those skilled in the art will understand that certain modifications may fall within the scope of this disclosure.
Claims
1. A refrigerant compressor, comprising: A shaft that can rotate about its axis; A first radial stage, the first radial stage including a first radial impeller coupled to the shaft; An axial stage, fluidly located downstream of the first radial stage, including an axial stage impeller coupled to the shaft; and The second radial stage is fluidly located downstream of the axial stage and includes a second radial impeller coupled to the shaft.
2. The refrigerant compressor as claimed in claim 1, comprising: A U-shaped return channel is fluidly located between the first radial stage and the axial stage.
3. The refrigerant compressor as described in claim 1, wherein, This axial stage includes an axial stage stator.
4. The refrigerant compressor as claimed in claim 1, wherein, The first radial stage is configured such that the refrigerant flows parallel to the axis when entering the first radial impeller and flows radially outward when leaving the first radial impeller.
5. The refrigerant compressor of claim 4, comprising a return passage fluidly located downstream of the first radial impeller.
6. The refrigerant compressor as claimed in claim 5, wherein, The return channel is curved to smoothly redirect the refrigerant radially inward and axially toward the axial stage.
7. The refrigerant compressor as claimed in claim 6, wherein, The axial stage is configured such that refrigerant enters the axial stage impeller in a first direction and exits the axial stage stator in a second direction, and the first direction and the second direction are within 30 degrees parallel to the axis.
8. The refrigerant compressor of claim 7, wherein the first direction and the second direction are within 10 degrees parallel to the axis.
9. The refrigerant compressor of claim 7, comprising a volute, wherein, The second radial stage is configured such that the second radial impeller receives refrigerant flowing in the second direction and guides the refrigerant radially outward to the volute.
10. The refrigerant compressor of claim 1, comprising a volute, wherein, The second radial stage is configured such that the second radial impeller guides the refrigerant radially outward into the volute.
11. The refrigerant compressor of claim 1, comprising a housing, wherein the first radial stage, the axial stage, and the second radial stage are disposed within the housing.
12. A refrigerant compressor, comprising: A shaft that can rotate about its axis; Return to channel; Snail shell; A first radial stage, the first radial stage including a first radial impeller coupled to the shaft, the first radial impeller being configured to receive refrigerant flowing in a first direction and guide the refrigerant to the return channel in a second direction, wherein the return channel is configured to guide the refrigerant in a third direction; An axial stage, fluidly located downstream of the first radial stage, includes an axial stage impeller coupled to the shaft, wherein the axial stage is configured to receive refrigerant flowing in a fourth direction and output the refrigerant flowing in a fifth direction; and A second radial stage, fluidly located downstream of the axial stage, includes a second radial impeller coupled to the shaft and configured to guide the refrigerant into the volute in a sixth direction. The first direction, the fourth direction, and the fifth direction are within 30 degrees parallel to the axis, and the second direction, the third direction, and the sixth direction are within 30 degrees perpendicular to the axis.
13. The refrigerant compressor as claimed in claim 12, wherein, The first direction, the fourth direction, and the fifth direction are within 10 degrees parallel to the axis.
14. The refrigerant compressor of claim 12, wherein, The second direction, the third direction, and the sixth direction are within 10 degrees perpendicular to the axis.
15. The refrigerant compressor as claimed in claim 12, wherein, The second direction is substantially radially outward, and the third direction is substantially radially inward.
16. The refrigerant compressor of claim 12, comprising a housing, wherein the first radial stage, the axial stage, and the second radial stage are disposed within the housing.
17. The refrigerant compressor of claim 12, wherein, The return channel is U-shaped.
18. The refrigerant compressor of claim 12, wherein, The first, fourth, and fifth directions are within 10 degrees parallel to the axis; the second, third, and sixth directions are within 10 degrees perpendicular to the axis; and the second direction is substantially radially outward, and the third direction is substantially radially inward.
19. The refrigerant compressor of claim 18, comprising a housing, wherein the first radial stage, the axial stage, and the second radial stage are disposed within the housing.
20. The refrigerant compressor of claim 18, wherein, The return channel is U-shaped.