Multiple blade rows for impeller and diffuser stages

Abstract

A machine comprising a centrifugal impeller and a diffuser. The impeller has two rows of impeller blades. The first row accelerates the flow away from the axis of rotation and discharges the flow outward radially to the second row of impeller blades. The second row accelerates the flow first inward radially toward the axis of rotation, and then accelerates the flow in one axial direction. The diffuser has two rows of diffuser blades. The first row of diffuser blades accelerates the flow first in the first axial direction, and then accelerates the flow toward the axis of rotation. The second row of diffuser blades accelerates the flow first away from the axis of rotation, and then accelerates the flow in one axial direction, and then discharges the flow from the diffuser in the first axial direction.

Description

Technical Field

[0004] , , , ,

[0003]

[0001] The present subject matter relates to devices and methods for impeller stages and diffuser stages, particularly for use in multistage fluid machines.

Background Art

[0002] Multistage pumps and multistage compressors generally incorporate centrifugal impellers, each of which has an axial inlet and a radial outlet. Returning the fluid or gas to the impeller of the next stage results in a tortuous fluid path that follows a certain "obstacle course" between the relatively small-diameter impeller eye inlet and the large-diameter impeller discharge diameter and back through the interstage diffuser. Further, the radial discharge requires the diffuser to accept a radial flow. This results in an unnecessarily large diffuser diameter and an unnecessarily large overall diameter of the pump or compressor. In the case of a submersible well pump, the diameter allocated to the diffuser is not available for the impeller, so the number of stages needs to be increased to achieve the design head, while the flow capacity remains limited by the impeller diameter.

[0003] Constraining the fluid to the conventional axial impeller inlet / radial impeller outlet flow pattern in the meridional plane results in the need for a sharp reversal in the meridional plane in order to return the flow through the diffuser to the next stage. The need for a sharp reversal of direction in the meridional plane can be alleviated by following a more gently curved meridional path. For example, even a gently sinusoidal meridional path or a path consisting of circular arc segments and straight lines, nevertheless, the acceleration direction in the meridional plane has to reverse in the middle of the pump impeller and reverse again in the middle of the diffuser. This frustrates the attempts of designers to maintain smooth blade surfaces. This is because the acceleration vectors that the impeller blades and diffuser vanes have to impart to the flow change abruptly in the middle of the impeller and change abruptly again in the middle of the diffuser.

[0004] Referring to Figure 1, a conventional multistage centrifugal pump is shown. Note how large the pump casing is relative to the impeller diameter. Also note the winding fluid path from the outlet of one impeller to the inlet of the next. Such pumps are generally heavy, bulky, and inefficient compared to the disclosed technology. The efficiency of such multistage pumps is typically 60% to 80%.

[0005] Referring to Figure 2, a conventional multi-stage centrifugal compressor is shown. Here again, note the very large diameter of the required housing (labeled "D" in Figure 2) relative to the impeller diameter (labeled "d" in Figure 2). Similarly, note the winding flow path from the outlet of one impeller to the inlet of the next. [Overview of the Initiative]

[0006] The configuration of the disclosed technology addresses the shortcomings of the prior art. [Brief explanation of the drawing]

[0007] [Figure 1] This diagram shows a conventional multi-stage pump using conventional (non-tandem) blades. [Figure 2] This is a diagram showing a conventional multi-stage centrifugal compressor. [Figure 3] This is a cutaway diagram of a multi-stage tandem blade pump with an exemplary configuration. [Figure 4] Figure 3 is a cross-sectional view of a multi-stage tandem blade pump. [Figure 5] Figures 3 and 4 show schematic diagrams of the streamlines passing through one stage of a multi-stage tandem blade pump. [Figure 6] This figure shows an example of an acceleration vector with respect to wing angle. [Figure 7] This figure shows an example of an acceleration vector with respect to wing angle. [Figure 8] This is a quarter-sectional view of a multi-stage triple-blade pump with an exemplary configuration. [Figure 9]Figure 8 is a cross-sectional view of a multi-stage triple-blade pump. [Figure 10] Figure 8 shows an example of the stages in a multi-stage triple-blade pump. [Figure 11] This is a schematic diagram of the streamlines passing through the section shown in Figure 10. [Figure 12] This is an isometric view of the first side of the triple-blade diffuser stage in Figure 10, viewed individually. [Figure 13] This is an isometric view of the second side of the triple-blade diffuser stage in Figure 10, viewed individually. [Figure 14] This is an isometric view of the first side of the triple-blade impeller stage in Figure 10, viewed individually. [Figure 15] This is an isometric view of the second side of the triple-blade impeller stage in Figure 10, viewed individually. [Figure 16] Figure 8 is an exploded view of a multi-stage triple-blade pump. [Figure 17] Figure 10 shows an exploded axial section of an example of a triple-blade impeller stage, a triple-blade diffuser stage, and a bushing with internal splines. [Figure 18] This is a perspective view of a multi-stage, multi-blade pump, illustrating an example of an open-blade impeller configuration. [Figure 19] Figure 18 is a quarter-sectional view of a multi-stage, multi-blade pump. [Figure 20] Figure 18 is a cross-sectional view of a multi-stage, multi-blade pump. [Figure 21] Figure 18 shows a cross-sectional view of three stages of a multi-stage, multi-blade pump. [Figure 22] Figure 18 is a partial cross-sectional view of a multi-stage, multi-blade pump. [Figure 23] Figure 18 shows a 1 / 3 cross-sectional view of three stages of a multi-stage, multi-blade pump. [Figure 24] Figure 18 is a cross-sectional view of one impeller stage of a multi-stage, multi-blade pump. [Figure 25] Figure 18 shows another cross-sectional view of one impeller stage of a multi-stage, multi-blade pump. [Figure 26] Figure 18 is a cross-sectional view of one diffuser stage of a multi-stage, multi-blade pump. [Figure 27]A diagram showing an example of a multi-stage multiple row reversible pump turbine assembly installed in a vertical well. [Figure 28] A detailed view of a part of the assembly of FIG. 27. [Figure 29] A diagram showing another example of a multi-stage multiple row reversible pump turbine assembly installed in a vertical well. [Figure 30] A diagram showing yet another example of a multi-stage multiple row reversible pump turbine assembly installed in a vertical well. [Figure 31] A detailed view of a part of the assembly of FIG. 30. [Figure 32] A diagram showing an example of a prior art configuration having an annular water passage. [Figure 33] A diagram showing a cross-section of an example of a multi-stage pump turbine installed in a vertical well. [Figure 34] A diagram showing a part of the multi-stage pump turbine of FIG. 33 alone.

Modes for Carrying Out the Invention

[0008] As described herein, the aspects are directed to multi-stage multiple row centrifugal compressors or pumps that are improvements over the prior art.

[0009] The dilemma described in the background technology section, which troubles designers, can be resolved by using separate rows of blades within any impeller stage and any diffuser stage. Each of these rows of blades may be configured to provide continuous meridional acceleration from the leading edge to the trailing edge. This approach may eliminate meridional changes in acceleration within any single row of blades. This eliminates the need to twist the blade between different meridional acceleration zones, thus eliminating flow separation, secondary flow, and efficiency loss that tend to occur with twisted blades. The number of rows of blades depends on the number of different meridional acceleration zones. Therefore, a solution to avoid the abrupt changes in blade orientation that would otherwise occur in the mid-code (i.e., between the leading and trailing edges of the blade) where the acceleration vector in the meridional plane should change is simply to clearly divide the rows of blades with different orientations. Each row of blades is oriented according to its required action on the fluid.

[0010] The intent of this technology is that the zones may be filled with only two rows (i.e., two blade rows), but this comes at the cost of a larger axial length of the stage, as well as increased weight, size, and cost of the machine (all compared to the version with three blade rows). In this configuration, tandem blades may be used. The first impeller blade row may receive the axial inlet flow, then accelerate the flow away from the axis of rotation, and discharge radially to the second impeller blade row. The second impeller blade row receives the radial inlet flow and accelerates the flow in a circular manner in the meridional plane, first axially, and then gradually toward the axis of rotation. The second impeller blade row of this tandem blade row pair discharges axially to a subsequent diffuser blade row, which initiates acceleration of the flow radially inward, then gives the fluid a radially inward flow direction, and then gradually changes the direction of acceleration to the axial direction. The next diffuser blade row initially accelerates the flow axially, then smoothly transitions to radially outward acceleration of the flow. In a tandem diffuser, this second blade row ends, discharging the flow axially to either the next impeller stage or the outlet manifold.

[0011] An even more axially compact arrangement may be constructed by using three blade rows at each stage, which may be used to accelerate the flow from the axial inlet and align it with a substantially radial blade row. This substantially radial blade row is then followed by a final blade row that receives a substantially radial inlet but discharges axially.

[0012] Similar opportunities to adjust acceleration and deceleration vectors arise in each diffuser stage, where the incoming axial flow (typically large diameter) from the preceding impeller must first be accelerated to flow radially toward the shaft centerline, and then, along the way, be accelerated again to flow axially and align with the next impeller stage. To achieve the acceleration changes required within the same impeller stage, two separate tandem blade rows may be used to avoid the use of abruptly twisted continuous blades that would cause flow separation, secondary flow, and cavitation. The first of the tandem blade rows is aligned to convert tangential kinetic energy into pressure and to direct the flow toward the shaft centerline. The second half of the tandem stage is aligned on one axis to continue converting tangential kinetic energy into pressure, while being aligned on a nearly orthogonal axis and in the meridional plane to accelerate the flow toward the shaft centerline. This can also be thought of as decelerating the approach to the shaft centerline. To achieve the required flow, this switching of acceleration vectors and surface orientation in the mid-chord is necessary, but this is impossible without interrupting the wing surface and splitting the virtual single wing into two more effective tandem wings.

[0013] The excellent performance of the axial inlet and outlet impellers in U.S. Patent No. 11300093 supports the idea that uninterrupted, continuous acceleration and uninterrupted, continuous blade orientation prevent secondary flow and the resulting flow separation that degrade efficiency. According to the disclosed technology, these advantages can be extended to multistage centrifugal pumps and multistage centrifugal compressors. It should be noted that secondary flow and flow separation can lead to turbulence, which in turn can lead to cavitation. Therefore, the disclosed technology not only improves pump efficiency but also generally reduces cavitation levels.

[0014] Furthermore, while the following description refers to pumps for brevity and readability, it should be recognized that fluid machinery does not necessarily have to be pumps in all configurations. Instead, fluid machinery may, for example, be turbines, blowers, compressors, turbochargers, superchargers, gas turbines, reversible pump turbines, or other fluid machinery or aerospace machinery. In addition, it should be noted that the disclosed technology is applicable to single-stage fluid machinery as well as multi-stage fluid machinery, which is the focus of the following description.

[0015] With that introduction, Figure 3 is a cutaway view showing a portion of a multistage tandem blade pump in an exemplary configuration. Figure 4 is a cross-sectional view of the multistage tandem blade pump of Figure 3. As shown in Figures 3 and 4, the multistage tandem blade pump 200 may include multiple pump stages. Specifically, Figures 3 and 4 show a first pump stage 67, a second pump stage 68, and a third pump stage 69. The first pump stage 67 includes a first impeller stage 1 and a first diffuser stage 4 housed in a first impeller housing 20. The second pump stage 68 includes a second impeller stage 2 and a second diffuser stage 5 housed in a second impeller housing 21. The third pump stage 69 includes a third impeller stage 3 and a third diffuser stage 6 housed in a third impeller housing 22. While Figures 3 and 4 show three pump stages, a tandem blade row pump according to the disclosed technology may have more than three stages (e.g., four, five, or more) or fewer than three stages (e.g., one or two).

[0016] The spline shaft 19 drives the first pump stage 67, the second pump stage 68, and the third pump stage 69, respectively. Thus, the rotating shaft 86 of each pump stage is collinear with the shaft 19. Bearing 25 supports the shaft 19 in the first pump stage 67, bearing 24 supports the shaft 19 in the second pump stage 68, and bearing 23 supports the shaft 19 in the third pump stage 69. The bearing arrangements depicted in Figures 3 and 4 and elsewhere in this disclosure are just one of many alternatives. As a result, various fluid membrane bearings, rolling bearings, gas membrane bearings, or magnetic bearings may be used depending on the application and the fluid being pumped.

[0017] Since the structure of each pump stage is substantially the same, we will further explain its structure with respect to the first pump stage 67.

[0018] As previously mentioned, the first pump stage 67 includes a first impeller stage 1 that operates centrifugally around the shaft 19. In the illustrated configuration, the first impeller stage 1 is housed in the first impeller housing 20. As shown in Figures 3 and 4, the first impeller stage 1 has two separate rows of impeller blades. The first row of impeller blades 7 is configured to receive flow in a first axial direction 150, accelerate the flow on vectors 26, 27 (see description in Figure 5) away from the axis of rotation 86, and discharge the flow outward radially 152 to the second row of impeller blades 8. The first axial direction 150 will be referred to as the forward axial direction in the following description, taking into account the direction of flow in the illustrated configuration. The second row 8 of the impeller blades is configured to receive the outward radial fluid flow from the first row 7 of the impeller blades, accelerate the flow in the outward radial direction 153 on vectors 28, 29 toward the axis of rotation 86 (see explanation in Figure 5), and then accelerate the fluid in the forward axis direction 150.

[0019] As previously mentioned, the first pump stage 67 includes a first diffuser stage 4 that operates around the shaft 19 but does not rotate around the shaft 19. As shown in Figures 3 and 4, the first diffuser stage has two diffuser blade rows. The first row of diffuser blades 9 is configured to receive the flow from the first impeller stage 1, accelerate the flow in the forward axis direction 150, and then accelerate the flow on vectors 30, 31 (see description in Figure 5) toward the rotation axis 86. The second row of diffuser blades 10 is configured to receive the inward radial flow from the first row of diffuser blades 9, accelerate the flow first on vectors 32, 33 (see description in Figure 5) toward the rotation axis 86, and then accelerate the fluid in the forward axis direction 150, and then discharge the fluid from the first diffuser stage 4 in the forward axis direction 150. In a configuration having multiple pump stages, as shown in Figures 3 and 4, the second row 10 of the diffuser blades is configured to discharge fluid from the first diffuser stage 4 to the second impeller stage 2.

[0020] Figure 5 is a schematic diagram of the streamlines passing through the first pump stage 67 of the multi-stage tandem blade row pump shown in Figures 3 and 4. As shown in Figures 4 and 5, acceleration vectors in the meridional plane are identified by reference numbers 26 to 33. Specifically, the acceleration of the fluid flow caused by the first row 7 of the impeller blades of the first impeller stage 1 is represented by outward vectors 26 and 27. The acceleration of the fluid flow caused by the second row 8 of the impeller blades of the first impeller stage 1 is represented by inward vectors 28 and 29. The second row 8 of the impeller blades of the first impeller stage 1 continues the same acceleration as the first row 7 of the impeller blades perpendicular to the meridional plane, but provides an acceleration in the opposite direction as shown by inward vectors 28 and 29. As described above with respect to Figures 3 and 4, different net acceleration vectors are preferably achieved by separate rows of blades, which benefit from a newly energized boundary layer that is less prone to flow separation than a continuous but highly twisted blade configured to give opposing accelerations as shown in Figure 5.

[0021] Similarly, the acceleration of the fluid flow caused by the first row 9 of the diffuser blades of the first diffuser stage 4 is represented by inward vectors 30 and 31. The acceleration of the fluid flow caused by the second row 10 of the diffuser blades of the first diffuser stage 4 is represented by outward vectors 32 and 33. In other words, the flow must first be accelerated toward the shaft centerline, but before reaching it, its inward velocity must be reduced so that when it reaches the impeller eye of the subsequent pump stage, its flow direction becomes axial and aligns with the eye of the subsequent impeller. The direction of axial acceleration is shown by vector 81 in Figure 5. Similar to the first impeller stage 1, the different net acceleration vectors shown for the first diffuser stage 4 are preferably achieved by separate blade rows for the reasons stated for the first diffuser stage 4.

[0022] Although not shown individually, the acceleration of the other stages is substantially the same as that described in Figure 5 for the first pump stage 67.

[0023] Figures 6 and 7 show examples of acceleration vectors imparted to the fluid flow by an impeller blade 96, such as the blades in the first row 7 of the impeller blades of the first impeller stage 1. As shown in Figures 6 and 7, the blade surface 87 imparts a net acceleration 84 to the fluid flow as the blade surface 87 rotates around the axis of rotation 86. The net acceleration 84 is oriented perpendicular to the blade surface 87 and consists of radial acceleration components 82 and axial acceleration components 81, both located in the meridional plane 85, as well as a tangential component 83. The acceleration in the meridional plane guides the fluid flow within the meridional plane, while the tangential component 83 imparts energy to the fluid flow (in the case of a pump or compressor). The required acceleration direction in the meridional plane reverses (e.g., from outward to inward, or vice versa), while the tangential acceleration 83 is maintained to achieve the design head of a particular stage. Similar acceleration and deceleration are imparted to the fluid flow by diffuser blades. Referring particularly to Figure 7, configuring the surface of the wing 96 to be parallel to the isobars 97 maximizes the minimum pressure for a given wing loading and thus optimizes cavitation performance.

[0024] Returning to Figures 3 and 4, as shown, the second impeller stage 2 operates centrifugally around the axis 19. The second impeller stage 2 has two rows of impeller blades. The first row 11 of the impeller blades of the second impeller stage 2 is configured to receive the fluid flow from the first diffuser stage 4, accelerate the flow in a vector away from the rotation axis 86, and discharge the flow outward radially to the second row 12 of the impeller blades of the second impeller stage 2. The second row 12 of the impeller blades of the second impeller stage 2 is configured to receive the outward radial flow from the first row 11 of the impeller blades of the second impeller stage 2, accelerate the flow first in a vector toward the rotation axis 86 in the inward radial direction, and then accelerate the fluid in the forward axis direction 150.

[0025] As shown in Figures 3 and 4, the second diffuser stage 5 operates around the axis 19 but does not rotate around the axis 19. The second diffuser stage 5 has two diffuser blade rows. The first row 13 of the diffuser blades of the second diffuser stage 5 is configured to receive the flow from the second impeller stage 2 and accelerate the flow first in the forward axis direction 150, and then accelerate the flow in a vector toward the rotation axis 86. The second row 14 of the diffuser blades of the second diffuser stage 5 is configured to receive the inward radial flow 153 from the first row 13 of the diffuser blades of the second diffuser stage 5 and accelerate the flow first in a vector toward the rotation axis 86, and then accelerate the fluid in the forward axis direction 150, and then discharge the fluid from the second diffuser stage 5 in the forward axis direction 150.

[0026] As shown in Figures 3 and 4, the third impeller stage 3 operates centrifugally around the axis 19. The third impeller stage 3 has two rows of impeller blades. The first row 15 of the impeller blades of the third impeller stage 3 is configured to receive the fluid flow from the second diffuser stage 5, accelerate the flow in a vector away from the rotation axis 86, and discharge the flow outward radially to the second row 16 of the impeller blades of the third impeller stage 3. The second row 16 of the impeller blades of the third impeller stage 3 is configured to receive the outward radial flow from the first row 15 of the impeller blades of the third impeller stage 3, accelerate the flow first in a vector toward the rotation axis 86 in the inward radial direction, and then accelerate the fluid in the forward axis direction 150.

[0027] As shown in Figures 3 and 4, the third diffuser stage 6 operates around the axis 19 but does not rotate around the axis 19. The third diffuser stage 6 has two rows of diffuser blades. The first row 17 of the diffuser blades of the third diffuser stage 6 is configured to receive the flow from the third impeller stage 3 and accelerate the flow first in the forward axis direction 150, and then accelerate the flow in a vector toward the rotation axis 86. The second row 18 of the diffuser blades of the third diffuser stage 6 is configured to receive the inward radial flow 153 from the first row 17 of the diffuser blades of the third diffuser stage 6 and accelerate the flow first in a vector away from the rotation axis 86, and then accelerate the fluid in the forward axis direction 150, and then discharge the fluid from the third diffuser stage 6 in the forward axis direction 150.

[0028] Each impeller stage and each diffuser stage has an outer diameter. For clarity, these diameters are shown in Figure 4 only for the first impeller stage 1 and the third diffuser stage 6. In the configuration, the outer diameter 154 of the impeller stage is not greater than the outer diameter 155 of the corresponding diffuser stage. In the configuration, the outer diameter 154 of the impeller stage is substantially equal to the outer diameter 155 of the corresponding diffuser stage. When used in this context, "substantially equal" means being equivalent in most respects or in essence without requiring complete identity.

[0029] The computational fluid dynamics (CFD) solutions for the pump configurations in Figures 3 and 4 demonstrate computational efficiency exceeding 90%. This good computational efficiency is consistent with the relative lack of secondary flow and the absence of flow separation resulting from the tandem blade configuration.

[0030] The multi-stage tandem blade row pump 200 described above in Figures 3 and 4 can be made shorter by axially flattening each impeller stage and each diffuser stage. Doing so introduces a third acceleration zone (less acceleration in the meridional plane), which is preferably handled by a third blade row located between the two blade rows described for the tandem blade row pump 200.

[0031] Figure 8 is a quarter-sectional view showing a portion of a multistage triple-blade pump in an exemplary configuration. Figure 9 is a cross-sectional view of the multistage triple-blade pump of Figure 8. Figure 10 shows the stages of an example of the multistage triple-blade pump of Figure 8. Figure 11 is a schematic diagram of the streamlines through the stages of Figure 10. As shown in Figures 8 to 11, the multistage triple-blade pump 300 may include multiple pump stages, each having a diffuser stage 64 and an impeller stage 65. A shaft 19 drives each pump stage, and the rotation axis 86 of each pump stage is collinear with the shaft 19. As shown, the fluid enters the pump stage through the inlet manifold 34 or inlet manifold 35 and exits the pump stage through the outlet manifold 36.

[0032] Since each diffuser stage 64 and each impeller stage 65 are substantially identical, they will be described below using representative examples.

[0033] Referring particularly to Figures 10 and 11, the centrifugal impeller stage 65 is configured to rotate around the rotation axis 86. The impeller stage 65 has three separate rows of impeller blades. The first row of impeller blades 72 is configured to receive a fluid flow Q in the forward axial direction 150, for example, from the inlet manifold or the diffuser stage of a preceding pump stage. The first row of impeller blades 72 is configured to accelerate the flow Q on a vector away from the rotation axis 86 and discharge the fluid flow Q outward radially 152 to the second row of impeller blades 71. Thus, the first row of impeller blades 72 changes the flow direction in the meridional from axial to radially outward, while also providing tangential acceleration. The second row of impeller blades 71 is configured to accelerate the flow Q outward radially 152 by the impeller radial velocity component 79 and to accelerate the flow Q in the second axial direction 151 by the impeller axial velocity component 78. The second axial direction 151 is opposite to the first axial direction 150. Considering the direction of flow in the illustrated configuration, the second axial direction 151 will be referred to as the reverse axial direction 151 in the following description. In the configuration, the axial velocity component may be, for example, less than 10% of the value of the radial velocity component. The second row 71 of the impeller blades maintains the impeller flow direction 80 in the meridional plane approximately radially outward, and the impeller flow direction 80 consists of an impeller radial velocity component 79 and an impeller axial velocity component 78. The third row 70 of the impeller blades receives the outward radial flow Q from the second row 71 of the impeller blades 152, and is configured to first accelerate the flow Q in the inward radial direction 153 on a vector toward the rotation axis 86, and then accelerate the fluid flow Q in the forward axial direction 150. Therefore, the third row 70 of the impeller blades continuously imparts kinetic energy to the fluid flow Q while simultaneously providing acceleration in the meridional plane to discharge the flow axially to the subsequent diffuser stage 64.

[0034] Therefore, the velocity of the flow Q exiting the second row 71 of the impeller blades is nominally radial within the meridional plane. However, a moderate impeller axial velocity component 78 parallel to the rotation axis 86 shortens the length of each pump stage, and consequently the overall length of the stacked pump stages. The increased axial spacing of the pump stages increases the critical axial velocity, reduces the required shaft diameter, decreases the bearing size, reduces bearing losses, and ultimately reduces the overall size, weight, and cost of the pump.

[0035] As a result, the change in meridional flow direction within the impeller stage 65 is efficiently achieved with minimal flow separation and minimal secondary flow generation. Importantly, the fluid remains within the impeller stage 65 for as long as possible, while being carried to the maximum possible radius, without requiring a larger diameter impeller or a diffuser larger than the impeller. In this way, efficiency is increased while reducing size, weight, and manufacturing costs. This concept can be extended to any number of blade rows used in each impeller stage and diffuser stage.

[0036] The diffuser stage 64 is located around the rotation axis 86 but does not rotate around the rotation axis 86. The diffuser stage 64 has three diffuser blade rows. The first row of diffuser blades 75 receives the flow Q from the preceding impeller stage 65 and is configured to first accelerate the flow Q in the forward axial direction 150 and then accelerate the flow Q in a vector toward the rotation axis 86. The second row of diffuser blades 74 is configured to accelerate the flow in the inward radial direction 153 by the diffuser radial velocity component 160 and to accelerate the flow Q in the reverse axial direction 151 by the diffuser axial velocity component 159. Thus, the diffuser flow direction 161 in the meridional plane consists of the diffuser radial velocity component 160 and the diffuser axial velocity component 159. The third row 73 of the diffuser blades is configured to receive an inward radial flow Q 153 from the second row 74 of the diffuser blades, first accelerating the flow Q in a vector away from the rotation axis 86, then accelerating the fluid flow Q in the forward axis direction 150, and then discharge the fluid flow Q from the diffuser stage 64 in the forward axis direction 150. In a configuration with multiple stages, the third row 73 of the diffuser blades discharges the fluid flow Q from the diffuser stage 64 to the second impeller stage 65. As shown in Figures 8 and 9, the second impeller stage 65 may have a corresponding second diffuser stage 64.

[0037] Therefore, similar to the impeller stages 65, each diffuser stage 64 may also be shortened in length by adding an impeller axial velocity component 78 to the mean meridional streamlines in the second row 74 of the diffuser blades. This shortens the stage spacing while allowing for a hydraulically efficient bending radius in the third row 70 and the first row 72 of the impeller blades, and in the third row 73 and the first row 75 of the diffuser blades.

[0038] Referring particularly to Figure 10, each impeller stage 65 and each diffuser stage 64 has an outer diameter. In the configuration, the outer diameter 154 of the impeller stage 65 is not greater than the outer diameter 155 of the corresponding diffuser stage 64. In the configuration, the outer diameter 154 of the impeller stage 65 is substantially equal to the outer diameter 155 of the corresponding diffuser stage 64. When used in this context, "substantially equal" means being equivalent in most respects or in essence without requiring complete identity.

[0039] Continuing primarily with reference to Figure 10, the shaft 19 is splined and drives the impeller stage 65 via splines 77. An internally splined bush 66 rotates with the shaft 19 and is fluid-lubricated and supported by a bearing 76 mounted within a (non-rotating) diffuser stage 64. A number of such impeller-diffuser pairs may be stacked, with the impeller stage 65 driven by a common shaft 19. Seals between the impeller stage 65 and the diffuser stage 64 can be achieved by labyrinth seals 91, 92, 93, and 94, or other sealing options. Thrust forces can optionally be balanced by assembling an equal number of impeller stages rotating clockwise and counterclockwise (e.g., viewed from the inlet) together with the corresponding diffuser stages on a common shaft. A notable feature of the disclosed technology is that the diffuser stage does not need to be any larger in diameter than the impeller stage (or runner in the case of a turbine). Achieving a small diffuser diameter is possible by redirecting the nominally radially outward flow in the impeller stage into an axial flow within the meridional plane before handing the flow over to the diffuser stage.

[0040] Figure 12 is an isometric view of the first side of the triple-blade diffuser stage of Figure 10, viewed in isolation. Figure 13 is an isometric view of the second side of the triple-blade diffuser stage of Figure 10, viewed in isolation. The diffuser stage 64 in Figures 12 and 13 is as described above for Figures 8 to 11.

[0041] Figure 14 is an isometric view of the first side of the triple-blade impeller stage of Figure 10, viewed in isolation. Figure 15 is an isometric view of the second side of the triple-blade impeller stage of Figure 10, viewed in isolation. The impeller stage 65 in Figures 14 and 15 is as described above for Figures 8 to 11.

[0042] Figure 16 is an exploded view of the multi-stage triple-blade pump of Figure 8. Figure 17 is an exploded axial section view of an example of the triple-blade impeller stage of Figure 10, the triple-blade diffuser stage of Figure 10, and the internally splined bush 66. The labeled components are as described above for Figures 8 to 15. In addition, the internally splined bush 66 rotates with the shaft 19 in the central gap of the diffuser stage 64. The components are held together by a tie rod 88 and a nut 95.

[0043] Figure 18 is a perspective view showing a portion of a multi-stage multi-blade pump, illustrating an example of an open blade impeller in an exemplary configuration. Figure 19 is a quarter-section of the multi-stage multi-blade pump of Figure 18. Figure 20 is a cross-section of the multi-stage multi-blade pump of Figure 18. Figure 21 is a cross-section of three stages of the multi-stage multi-blade pump of Figure 18. Figure 22 is a partial cross-section of a portion of the multi-stage multi-blade pump of Figure 18. Figure 23 is a one-third cross-section of three stages of the multi-stage multi-blade pump of Figure 18. Figure 24 is a cross-section of one impeller stage of the multi-stage multi-blade pump of Figure 18. Figure 25 is another cross-section of one impeller stage of the multi-stage multi-blade pump of Figure 18. Figure 26 is a cross-section of one diffuser stage of the multi-stage multi-blade pump of Figure 18.

[0044] As shown in Figures 18 to 26, the multi-stage multi-blade pump 400 is substantially the same as the multi-stage triple-blade pump 300 described above for Figures 8 to 11. Therefore, features not described here are as described above for the multi-stage triple-blade pump 300 in Figures 8 to 11. The configuration shown in Figures 18 to 26 differs from the configuration shown in Figures 8 to 11 mainly in that the first row 51 of the impeller blades is closed and may be located between the impeller band 54 and the impeller hub 55 and be integrated with them. In other words, the first row 51 of the impeller blades is "closed" because the flow through the first row 51 of the impeller blades is partially bounded by the other parts of the impeller stage 65. As shown in the figure, the second row 52 and the third row 53 of the impeller blades are open, meaning that the flow through the second row 52 and the third row 53 of the impeller blades is partially bounded by the non-rotating diffuser stage 64. In other words, the flow through the second row 52 and the third row 53 of the impeller blades passes through a flow path 156 that is bounded on the first axial side by the surface 157 of the impeller stage 65 and on the second axial side by the surface of the diffuser stage 64, i.e., the runner crown 58.

[0045] As shown in Figures 18 to 26, the centrifugal impeller stage 65 is configured to rotate around a rotation axis 86 that is collinear with the axial tie rod 60 (which will be described further below). The impeller stage 65 has three separate rows of impeller blades. The first row of impeller blades 51 is configured to receive fluid flow in an inward radial direction 153 from inlet manifolds 34, 35 or the diffuser stage 64 of a preceding pump stage, etc. The first row of impeller blades 51 is configured to accelerate the flow first away from the rotation axis 86 and then toward the rotation axis 86, and discharge the fluid flow outward radially 152 to the second row of impeller blades 52. The second row of impeller blades 52 is configured to accelerate the flow outward radially 152. The third row 53 of the impeller blades is configured to receive the outward radial flow 152 from the second row 52 of the impeller blades, first accelerating the flow in the inward radial direction 153 along a vector toward the rotation axis 86, and then accelerating the fluid flow in the forward axis direction 150 to discharge the flow axially to the subsequent diffuser stage 64.

[0046] Multiple impeller hubs 55 may be stacked end to end, forming a (split) shaft with both bending and torsional rigidity and strength. The stacked impeller hubs 55 may be held together by shaft tie rods 60 passing through holes 56 in the impeller hubs 55. Housing sections 37, 38, 39, 40, 41, and 42 are held together by housing tie rods 88. A runner crown 58 surrounds rows 51, 52, and 53. A labyrinth seal 57 provides interstage sealing. To transmit torque from one impeller hub 55 to the next, for example, a face key or dowel may be used. The diffuser stage 64 may incorporate a cooling passage 62, which may function, for example, as a heat pipe or be used for liquid cooling.

[0047] Each diffuser stage 64 is located around the rotation axis 86 but does not rotate around the rotation axis 86. In the illustrated configuration, the diffuser stage 64 has two rows of diffuser blades. The first row of diffuser blades 89 is configured to receive the flow from the preceding impeller stage 65 and accelerate the flow first in the forward axial direction 150, and then in a vector toward the rotation axis 86. The second row of diffuser blades 90 is configured to accelerate the flow in the inward radial direction 153. Thus, the second row of diffuser blades 90 is nominally radial. In a configuration with multiple stages, the second row of diffuser blades 90 discharges the fluid flow from the diffuser stage 64 to the next impeller stage 65.

[0048] Assembly may be carried out by stacking impeller stages 65 between diffuser stages 64, securing the impeller stages 65 together with tie rods 60 (which may be enlarged to accommodate heat pipes), and bolting the diffuser stages 64 together with tie rods 88. Inlet manifolds 34, 35 may be used at one or both ends of the assembly 400. One or more discharge manifolds 36 may also be used within the assembly 400.

[0049] Figure 27 shows a portion of an example of a multistage multi-blade reversible pump turbine assembly installed in a vertical well. Figure 28 is a detailed view of a portion of the assembly in Figure 27. As shown in Figures 27 and 28, the multistage multi-blade reversible pump turbine assembly 500 in Figures 27 and 28 may include the multistage tandem blade pump 200 in Figures 3 and 4. Thus, the components identified in Figures 27 and 28 are the same as those described above for the components having the same reference numbers in Figures 3 and 4. Although depicted as having three stages, as mentioned above, the multistage tandem blade pump 200 may have fewer than three stages or more than three stages in some configurations.

[0050] Furthermore, the multistage tandem blade reversible pump turbine assembly 500 in Figures 27 and 28 may also include an underwater motor generator 43 and an associated underwater electrical connector 47. As previously mentioned, since the well 100 is vertical, considering the direction of gravity, "up" is the direction upward in Figure 27 and "down" is the direction downward in Figure 27. As a result, the electrical connector 47 is located below the underwater motor generator 43 at the bottom of the well 100, and the underwater motor generator 43 is located below the multistage tandem blade pump 200.

[0051] In the pump mode of the reversible pump turbine assembly 500, the flow descends through the annular passage 45 into the well 100. The annular passage 45 discharges (in pump mode) into the inlet manifold 34. The flow in pump mode then enters the first pump stage 67 axially, and the flow proceeds through the multi-stage tandem blade pump 200 as described above with respect to Figures 3 and 4.

[0052] It should be noted that the illustrated configuration results in a smaller overall machine diameter of 98 for a given impeller diameter of 154 than that achieved in the conventional multi-stage pump turbine shown in Figure 32, where the impeller discharges flow radially. The head generated at each stage at any given shaft speed is generally proportional to the square of the impeller diameter. Minimizing the machine diameter of 98 reduces not only the size, weight, and cost of the machine, but also the required diameter and cost of the well needed for installation. It should be noted that well construction involves significantly less geological risk and construction cost than the construction of an underground power plant.

[0053] Figure 29 shows another example of a multi-stage, multi-blade reversible pump-turbine assembly installed in a vertical well. The multi-stage, multi-blade reversible pump-turbine assembly 600 in Figure 29 is hydraulically similar to the multi-stage, multi-blade reversible pump-turbine assembly 500 in Figures 27 and 28, except that the motor-generator 43 is located above the multi-stage, tandem blade pump 200. Consequently, the motor-generator 43 in Figure 29 may be, for example, an air-cooled ground-based motor-generator. As with Figure 27, considering the direction of gravity, "up" is the direction upward in Figure 29, and "down" is the direction downward in Figure 29.

[0054] Figure 30 shows yet another example of a reversible pump-turbine assembly 700 installed in a vertical well 100. Figure 31 is a detailed view of a portion of the reversible pump-turbine assembly 700 in Figure 30. As with Figure 27, considering the direction of gravity, "up" is the direction upward in Figure 30 and "down" is the direction downward in Figure 30.

[0055] As illustrated, the outer diameter of the multistage pump turbine 101 is reduced by utilizing a water passage 47 within the power transmission shaft 19 for supplying water to the pump inlet 49. The impact of allocating the center of the shaft 19 to water supply on the torque capacity of the shaft 19 is minimal. This arrangement eliminates the need for the annular water passage 48 shown in Figure 32. This results in a pump turbine with a smaller overall machine diameter 98, and consequently, a relatively smaller diameter and lower cost well 100. As illustrated, the first pump stage 50 is similar to the pump configuration disclosed in U.S. Patent No. 11300093. Thus, the first pump stage 50 includes a first impeller stage configured to rotate around a rotating shaft (collinear with the hollow shaft 120), receive a fluid flow from a second axial direction 151, redirect the fluid flow through a toroidal fluid passage, and discharge the fluid flow to a first diffuser stage of the first pump stage 50 in the first axial direction 150 opposite to the second axial direction 151. Note that the torque between the motor shaft 61 and the pump shaft 19 is transmitted via the pump blades 63.

[0056] The second pump stage 104, the third pump stage 105, and the fourth pump stage 106 may utilize a mixed-flow impeller according to a conventional design or the tandem blade row technology described in reference to Figures 3 and 4 of this patent application. Thus, the second pump stage 104, the third pump stage 105, and the fourth pump stage 106 may have the features described above for the first pump stage 67, the second pump stage 68, and the third pump stage 69 in Figures 3 and 4.

[0057] Connection to the pump may be achieved by using a “flow inverter” disclosed in U.S. Patent No. 11300093, which does not require the well 100 to withstand the pump outlet pressure and does not expose the low-pressure piping connection to external buckling pressure. U.S. Patent No. 11300093 is incorporated herein by reference.

[0058] Figure 32 shows an example of a conventional design having an annular water passage, which can be used as a point of comparison with some of the features described above.

[0059] Figure 33 is a cross-sectional view showing a portion of an example of a multistage reversible pump turbine 800 installed in a vertical well. Figure 34 shows a portion of the multistage pump turbine of Figure 33, i.e., the rotating assembly of Figure 33, in isolation. The multistage reversible pump turbine 800 of Figure 33 may be used, for example, instead of the multistage tandem blade pump 200 of Figure 27 or Figure 29, or the multistage pump turbine 101 of Figure 30.

[0060] As shown in Figure 33, a submersible multistage reversible pump turbine 800 is shown inside a vertical well 100. An inlet manifold 34 receives the flow from above. The inlet manifold 34 divides the flow between three upper pump stages 107, 108, and 109 and three lower pump stages 110, 111, and 112. As mentioned above, since the well 100 is vertical, considering the direction of gravity, "up" and "upward" are directions toward the top in Figure 33, and "down" and "downward" are directions toward the bottom in Figure 33. As a result, pump stage 112 is below the inlet manifold 34, while pump stage 109 is above the inlet manifold 34. The flow is recombined by an outlet manifold 113 and discharged to a diffuser 114. The diffuser 114 is surrounded by a heat pipe condenser 115, which is connected to a motor generator housing 116 by at least one heat pipe 117.

[0061] The shaft coupling 158 is hydraulically configured with streamlined torque-transmitting vanes 119, which allow the high-pressure fluid from the pump stage 112 to enter the hollow shaft 120. The hollow shaft 120 may feature continuous external splines for the purpose of driving impellers associated with the pump stages 107, 108, 109, 110, 111, and 112. The impellers may be axially spaced by internally splined journals similar to the bushings 66 in Figures 16 and 17.

[0062] The shaft coupling 158 may also incorporate a heat pipe condenser 118 for cooling the rotor of the motor generator (see motor generator 43 in Figure 27 or Figure 30). Note that the heat pipe condenser 118 may be extended into the hollow shaft 120 for a certain distance to more effectively cool the motor generator rotor. The shaft coupling 158 may be coupled to or integrated with the motor shaft of the motor generator, such as the motor shaft 61 shown in Figures 30 and 31.

[0063] An expandable seal 121 may be provided to mechanically center the assembly within the well 100. The expandable seal 121 may also serve to prevent sediment from entering and accumulating in the annular gap space between the well 100 and the motor generator. In a configuration with an expandable seal 121, the heat pipe 117 passes through the gaps between the segments of the expandable seal 121.

[0064] In the configuration, one or more stages of the multistage reversible pump turbine 800 in Figure 33 may include the tandem blade row technology described in reference to Figures 3 and 4 in this patent application. Thus, the forward axis direction 150 for the lower pump stages 110, 111, and 112 will be downward, while the forward axis direction 150 for the upper pump stages 107, 108, and 109 will be upward.

[0065] The illustrated configuration provides high head within a well 100 of limited diameter for multiple stages, each having a large impeller discharge diameter (relative to the machine outer diameter 122). Since the number of axially opposed pump stages is equal, the thrust is substantially balanced. The high-pressure discharge from the diffuser 114 is conveniently located in the middle of the well, where it may be transported upward in a relatively thin-walled penstock that does not suffer crushing, as would occur if the external pressure were higher than the internal pressure. Therefore, this configuration of the disclosed technology does not require a “flow inverter.”

[0066] In general, the present disclosure teaches the advantages of using vanes and blades to function as “cornering vanes” not only for extracting or imparting momentum from a gas or fluid, but also for simultaneously achieving a change of direction in the meridional plane. A change of direction in the meridional plane is essentially orthogonal to a change of angular momentum. The object of the present invention is to provide a blade surface that imparts the vector sum of the required momentum changes for both a fluid or gas being energized, or a fluid or gas from which energy is being extracted. This technological development is expected to set a new standard in efficiently managing the meridional flow paths of fluids and gases through turbomachinery. Opportunities for both energy saving and reduction of capital investment costs are important.

[0067] As can be easily understood from the above, the basic concept of the present invention may be embodied in various ways. It may include fluid machinery such as pumps, pump turbines, turbines, blowers, compressors, turbochargers, superchargers, or gas turbines, or other devices, in order to achieve a suitable method. In this application, fluid machinery methods are disclosed as part of the results shown to be achieved by the various devices described, and as steps specific to their use. They are simply natural consequences of using the devices as intended and described. Furthermore, while several devices are disclosed, it should be understood that they can be modified in many ways, not just to achieve specific methods. Importantly, with respect to all of the above, it should be understood that all these aspects are encompassed in this disclosure. [Examples]

[0068] Exemplary embodiments of the disclosed technology are provided below. Specific configurations of the technology may include one or more of the embodiments described below, and any combination thereof.

[0069] Embodiment 1 is a centrifugal impeller stage configured to rotate around a rotation axis, the impeller stage having two separate rows of impeller blades, the first row of impeller blades configured to receive fluid flow in a first axial direction, accelerate the fluid flow in a vector away from the rotation axis, and discharge the fluid flow outward radially to a second row of impeller blades, the second row of impeller blades configured to receive fluid flow outward radially from the first row of impeller blades, first accelerate the fluid flow in an inward radial direction in a vector toward the rotation axis, and then accelerate the fluid flow in a first axial direction, and the centrifugal impeller stage and rotation axis A machine comprising a diffuser stage, the diffuser stage having two rows of diffuser blades, the first row of diffuser blades configured to receive fluid flow from the impeller stage and accelerate the fluid flow first in a first axial direction, and then accelerate the fluid flow in a vector toward the axis of rotation, and the second row of diffuser blades configured to receive inward radial fluid flow from the first row of diffuser blades and accelerate the fluid flow first in a vector away from the axis of rotation, and then accelerate the fluid flow in a uniaxial direction, and then discharge the fluid flow from the diffuser stage in a first axial direction.

[0070] Embodiment 2 includes the machine described in Embodiment 1, wherein the impeller stage is a first impeller stage, a second row of diffuser blades configured to discharge fluid flow from the diffuser stage to the second impeller stage in a first axial direction, the second impeller stage is configured to rotate around a rotation axis, the second impeller stage has two rows of impeller blades, the first row of impeller blades of the second impeller stage is configured to receive fluid flow from the diffuser stage, accelerate the fluid flow in a vector away from the rotation axis, and discharge the fluid flow outward radially to the second row of impeller blades of the second impeller stage, the second row of impeller blades of the second impeller stage is configured to receive outward radial fluid flow from the first row of impeller blades of the second impeller stage, first accelerate the fluid flow in an inward radial direction in a vector toward the rotation axis, and then accelerate the fluid flow in a uniaxial direction.

[0071] Embodiment 3 includes the machine described in Embodiment 2, wherein the diffuser stage is a first diffuser stage, and the machine further comprises a second diffuser stage around a rotation axis, the second diffuser stage having two rows of diffuser blades, the first row of diffuser blades of the second diffuser stage configured to receive fluid flow from the second impeller stage and first accelerate the fluid flow in a first axial direction, and then accelerate the fluid flow in a vector toward the rotation axis, and the second row of diffuser blades of the second diffuser stage configured to receive inward radial fluid flow from the first row of diffuser blades of the second diffuser stage and first accelerate the fluid flow in a vector away from the rotation axis, and then accelerate the fluid flow in a uniaxial direction, and then discharge the fluid flow from the second diffuser stage in a first axial direction.

[0072] Example 4 includes the machine described in any one of Examples 1 to 3, wherein each of the impeller stage and the diffuser stage has an outer diameter, and the outer diameter of the impeller stage is not greater than the outer diameter of the diffuser stage.

[0073] Example 5 includes the machine described in Example 4, wherein the outer diameter of the impeller stage is substantially equal to the outer diameter of the diffuser stage.

[0074] Embodiment 6 includes a centrifugal impeller for machinery, comprising: a first row of impeller blades shaped and positioned to receive a fluid flow in a first axial direction, accelerate the fluid flow away from the rotation axis of the impeller, and discharge the fluid flow radially outward to a second row of impeller blades; and a second row of impeller blades shaped and positioned to receive a fluid flow radially outward from the first row of impeller blades, first accelerate the fluid flow in a vector toward the rotation axis in an inward radial direction, and then accelerate the fluid flow in a uniaxial direction.

[0075] Embodiment 7 includes a mechanical diffuser comprising: a first row of diffuser blades shaped and positioned to receive a fluid flow in a first axial direction, accelerate the fluid flow in the first axial direction, and then accelerate the fluid flow in a vector toward the axis of rotation; and a second row of diffuser blades shaped and positioned to receive an inward radial fluid flow from the first row of diffuser blades, accelerate the fluid flow first in a vector away from the axis of rotation, then accelerate the fluid flow in a uniaxial direction, and then discharge the fluid flow from the diffuser stage in the first axial direction.

[0076] Embodiment 8 is a centrifugal impeller stage configured to rotate around a rotation axis, the impeller stage having three separate rows of impeller blades, the first row of impeller blades configured to receive fluid flow in a first axial direction, accelerate the fluid flow on a vector away from the rotation axis, and discharge the fluid flow outward radially to the second row of impeller blades, the second row of impeller blades configured to accelerate the fluid flow outward radially by its radial velocity component and accelerate the fluid flow in the second axial direction by its axial velocity component, the second axial direction being opposite to the first axial direction, and the third row of impeller blades configured to receive fluid flow outward radially from the second row of impeller blades, first accelerating the fluid flow inward radially on a vector toward the rotation axis, and then accelerating the fluid flow in the first axial direction, A machine comprising: an impeller stage; and a diffuser stage around a rotation axis, the diffuser stage having three rows of diffuser blades, the first row of diffuser blades configured to receive the fluid flow from the impeller stage and accelerate the fluid flow first in a first axial direction, and then accelerate the fluid flow in a vector toward the rotation axis; the second row of diffuser blades configured to accelerate the fluid flow in an inward radial direction by a radial velocity component and in a second axial direction by an axial velocity component; and the third row of diffuser blades configured to receive the inward radial fluid flow from the second row of diffuser blades and accelerate the fluid flow first in a vector away from the rotation axis, and then accelerate the fluid flow in a uniaxial direction, and then discharge the fluid flow from the diffuser stage in a first axial direction.

[0077] Example 9 includes the machine described in Example 8, wherein each of the impeller stage and the diffuser stage has an outer diameter, and the outer diameter of the impeller stage is not greater than the outer diameter of the diffuser stage.

[0078] Example 10 includes the machine described in Example 9, wherein the outer diameter of the impeller stage is substantially equal to the outer diameter of the diffuser stage.

[0079] Embodiment 11 is configured such that the impeller stage is a first impeller stage, and the second row of diffuser blades is configured to discharge fluid flow from the diffuser stage in a first axial direction to a second impeller stage configured to rotate around the axis of rotation, the second impeller stage is configured to receive fluid flow in the first axial direction, accelerate the fluid flow on a vector away from the axis of rotation, and discharge fluid flow radially outward to the second row of impeller blades of the second impeller stage, the first row of impeller blades of the second impeller stage and the radial velocity component of the second impeller stage The machine includes, according to any one of Examples 8 to 10, a second row of impeller blades of a second impeller stage configured to accelerate the fluid flow in the outward radial direction and to accelerate the fluid flow in the second axial direction by the axial velocity component of the second impeller stage, and a third row of impeller blades of the second impeller stage configured to receive the outward radial fluid flow from the second row of impeller blades of the second impeller stage, and to first accelerate the fluid flow in the inward radial direction along a vector toward the axis of rotation, and then accelerate the fluid flow in one axial direction.

[0080] Embodiment 12 includes the machine described in Embodiment 11, wherein the diffuser stage is a first diffuser stage, and the machine further comprises a second diffuser stage around a rotation axis, the second diffuser stage comprising a first row of diffuser blades of the second diffuser stage configured to receive fluid flow from a second impeller stage and accelerate the fluid flow first in a first axial direction, and then accelerate the fluid flow in a vector toward the rotation axis; a second row of diffuser blades of the second diffuser stage configured to accelerate the fluid flow in an inward radial direction by a radial velocity component and accelerate the fluid flow in a second axial direction by an axial velocity component; and a third row of diffuser blades of the second diffuser stage configured to receive inward radial fluid flow from the second row of diffuser blades of the second diffuser stage and accelerate the fluid flow first in a vector away from the rotation axis, and then accelerate the fluid flow in a uniaxial direction, and then discharge the fluid flow from the diffuser stage in a first axial direction.

[0081] Embodiment 13 includes a centrifugal impeller for machinery, comprising: a first row of impeller blades configured to receive a fluid flow in a first axial direction, accelerate the fluid flow on a vector away from the rotation axis of the impeller, and discharge the fluid flow radially outward to a second row of impeller blades; a second row of impeller blades configured to accelerate the fluid flow radially outward by a radial velocity component and accelerate the fluid flow in a second axial direction by an axial velocity component, the second axial direction being opposite to the first axial direction; and a third row of impeller blades configured to receive a fluid flow radially outward from the second row of impeller blades, first accelerating the fluid flow radially inward on a vector toward the rotation axis, and then accelerating the fluid flow in a uniaxial direction.

[0082] Embodiment 14 includes a mechanical diffuser comprising: a first row of diffuser blades configured to receive fluid flow from an impeller stage and first accelerate the fluid flow in a first axial direction, and then accelerate the fluid flow in a vector toward the axis of rotation of the diffuser; a second row of diffuser blades configured to accelerate the fluid flow in an inward radial direction by its radial velocity component and accelerate the fluid flow in a second axial direction by its axial velocity component, the second axial direction being opposite to the first axial direction; and a third row of diffuser blades configured to receive inward radial fluid flow from the second row of diffuser blades and first accelerate the fluid flow in a vector away from the axis of rotation, then accelerate the fluid flow in a uniaxial direction, and then discharge the fluid flow from the diffuser stage in the first axial direction.

[0083] Example 15 is a centrifugal impeller stage configured to rotate around a rotation axis, the impeller stage having three separate rows of impeller blades, the first row of impeller blades configured to receive an inward radial fluid flow, accelerate the fluid flow first away from the rotation axis and then toward the rotation axis, and discharge the fluid flow outward radially to the second row of impeller blades, the second row of impeller blades configured to accelerate the fluid flow outward radially, the third row of impeller blades configured to receive an outward radial fluid flow from the second row of impeller blades, accelerate the fluid flow first inward radially toward the rotation axis, and then accelerate the fluid flow in the forward axial direction to discharge the fluid flow in the axial direction, centrifugal The machine includes an impeller stage and a diffuser stage around a rotation axis, the diffuser stage having two rows of diffuser blades, the first row of diffuser blades configured to receive fluid flow from the preceding impeller stage and accelerate the fluid flow first in the forward axial direction and then toward the rotation axis, and the second row of diffuser blades configured to accelerate the fluid flow in the inward radial direction and discharge the fluid flow from the diffuser stage to a subsequent impeller stage, wherein the fluid flow through the second row of impeller blades and the third row of impeller blades passes through a fluid channel bounded by the surface of the impeller stage on the first axial side and by the surface of the diffuser stage on the second axial side.

[0084] Embodiment 16 is a reversible pump turbine suitable for installation in a vertical well, comprising a multi-stage impeller-diffuser, a first impeller stage configured to rotate around a rotation axis, the first impeller stage having two separate rows of impeller blades, the first row of impeller blades configured to receive a fluid flow in the first axial direction, accelerate the fluid flow on a vector away from the rotation axis, and discharge the fluid flow outward radially to a second row of impeller blades, the second row of impeller blades receiving the outward radial fluid flow from the first row of impeller blades, first inward radially toward the rotation axis A first impeller stage configured to accelerate the fluid flow in a vector and then accelerate the fluid flow in a uniaxial direction, and a first diffuser stage around the axis of rotation, the first diffuser stage having two rows of diffuser blades, the first row of diffuser blades configured to receive the fluid flow from the impeller stage and first accelerate the fluid flow in a uniaxial direction and then accelerate the fluid flow in a vector toward the axis of rotation, the second row of diffuser blades receiving the inward radial fluid flow from the first row of diffuser blades and first accelerate the fluid flow in a vector away from the axis of rotation, then A first diffuser stage is configured to accelerate a fluid flow in one axial direction and then discharge the fluid flow from the first diffuser stage to the second impeller stage in the first axial direction, and a second impeller stage is configured to rotate around a rotation axis and has two rows of impeller blades, wherein the first row of impeller blades of the second impeller stage is configured to receive the fluid flow from the diffuser stage, accelerate the fluid flow on a vector away from the rotation axis, and discharge the fluid flow outward radially to the second row of impeller blades of the second impeller stage, and the second row of impeller blades of the second impeller stage A second impeller stage, configured to receive an outward radial fluid flow from a first row of blades, first accelerating the fluid flow in the inward radial direction along a vector toward the axis of rotation, and then accelerating the fluid flow in a uniaxial direction; and a second diffuser stage, located around the axis of rotation and having two rows of diffuser blades, wherein the first row of diffuser blades of the second diffuser stage is configured to receive a fluid flow from the second impeller stage, first accelerating the fluid flow in a uniaxial direction, and then accelerating the fluid flow along a vector toward the axis of rotation, and the second row of diffuser blades of the second diffuser stage isA reversible pump turbine includes a multistage impeller-diffuser having a second diffuser stage configured to receive an inward radial fluid flow from the first row of diffuser blades of the second diffuser stage, first accelerating the fluid flow in a vector away from the axis of rotation, then accelerating the fluid flow in a uniaxial direction, and then discharging the fluid flow from the second diffuser stage in a first axial direction; an annular passage radially surrounding the multistage impeller-diffuser; a manifold configured to receive the fluid flow discharged from the annular passage in a second axial direction and guide the fluid flow to the first impeller stage in a first axial direction, with the second axial direction being opposite to the first axial direction, and configured to receive the fluid flow discharged from the first impeller stage in a second axial direction and guide the fluid flow to the annular passage in a first axial direction in the pump mode of the reversible pump turbine; and a motor generator coupled to the multistage impeller-diffuser by an axis.

[0085] Example 17 includes the reversible pump turbine described in Example 16, wherein each of the first impeller stage and the first diffuser stage has an outer diameter, and the outer diameter of the first impeller stage is not greater than the outer diameter of the first diffuser stage.

[0086] Example 18 includes the reversible pump turbine described in Example 17, wherein the outer diameter of the first impeller stage is substantially equal to the outer diameter of the first diffuser stage.

[0087] Embodiment 19 comprises a first impeller stage configured to rotate around a rotation axis, receive a fluid flow from a first axial direction, change the direction of the fluid flow through a toroidal fluid channel, and discharge the fluid flow to a first diffuser stage in a second axial direction opposite to the first axial direction; a second impeller stage configured to rotate around a rotation axis, the second impeller stage having two separate rows of impeller blades, the first row of impeller blades configured to receive a fluid flow in the second axial direction, accelerate the fluid flow in a vector toward the rotation axis, and then discharge the fluid flow from the first diffuser stage to a second impeller stage in a second axial direction; and the second row of impeller blades configured to rotate from the first row of impeller blades outward. The machine includes: a second impeller stage configured to receive a radially directed fluid flow and first accelerate the fluid flow in the inward radial direction along a vector toward the axis of rotation, and then accelerate the fluid flow in two axial directions; and a second diffuser stage around the axis of rotation, the second diffuser stage having two rows of second diffuser blades, the first row of the second diffuser blades configured to receive the fluid flow from the second impeller stage and first accelerate the fluid flow in the second axial direction, and then accelerate the fluid flow along a vector toward the axis of rotation, and the second row of the second diffuser blades configured to receive the radially directed fluid flow from the first row of the second diffuser blades and first accelerate the fluid flow along a vector away from the axis of rotation, and then accelerate the fluid flow in two axial directions, and then discharge the fluid flow from the second diffuser stage in the second axial direction.

[0088] Embodiment 20 includes the machine described in Embodiment 19, wherein the second row of diffuser blades of the second diffuser stage is configured to discharge fluid flow from the second diffuser stage to the third impeller stage in the second axial direction, the third impeller stage is configured to rotate around a rotation axis, the third impeller stage has two rows of impeller blades, the first row of impeller blades of the third impeller stage is configured to receive fluid flow from the second diffuser stage, accelerate the fluid flow in a vector away from the rotation axis, and discharge the fluid flow outward radially to the second row of impeller blades of the third impeller stage, the second row of impeller blades of the third impeller stage is configured to receive outward radial fluid flow from the first row of impeller blades of the third impeller stage, first accelerate the fluid flow in an inward radial direction in a vector toward the rotation axis, and then accelerate the fluid flow in two axial directions.

[0089] Embodiment 21 includes the machine described in Embodiment 20, wherein the machine further comprises a third diffuser stage around a rotation axis, the third diffuser stage having two rows of diffuser blades, the first row of diffuser blades of the third diffuser stage being configured to receive fluid flow from the third impeller stage and first accelerate the fluid flow in a second axial direction, and then accelerate the fluid flow in a vector toward the rotation axis, and the second row of diffuser blades of the third diffuser stage being configured to receive inward radial fluid flow from the first row of diffuser blades of the third diffuser stage and first accelerate the fluid flow in a vector away from the rotation axis, and then accelerate the fluid flow in a second axial direction, and then discharge the fluid flow from the third diffuser stage in a second axial direction.

[0090] Example 22 includes the machine described in any one of Examples 19 to 21, wherein each of the second impeller stage and the second diffuser stage has an outer diameter, and the outer diameter of the second impeller stage is not greater than the outer diameter of the second diffuser stage.

[0091] Example 23 includes the machine described in Example 22, wherein the outer diameter of the second impeller stage is substantially equal to the outer diameter of the second diffuser stage.

[0092] *****

[0093] The contents of this document are presented for illustrative and explanatory purposes, but are not intended to be exhaustive or to be limited to the disclosure in the form provided. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of this disclosure. The forms of disclosure in this document have been selected and presented to illustrate the principles and practical applications of this disclosure and to enable those skilled in the art to understand this disclosure with various modifications suitable for the specific intended use.

[0094] Therefore, it should be understood that the disclosures herein include all possible combinations of the particular features referred to herein. For example, if a particular feature is disclosed in the context of a particular exemplary configuration, that feature may, wherever possible, also be used in the context of other exemplary configurations.

[0095] Furthermore, the described versions of the disclosed subject matter have many advantages that are described or that would be obvious to those skilled in the art. However, not all of these advantages or features are required in all versions of the disclosed apparatus, system, or method.

[0096] Furthermore, where this application refers to a method having two or more defined steps or operations, the defined steps or operations may be performed in any order or simultaneously, unless the context does not rule out such possibility.

[0097] The terms used herein are for illustrative purposes only and are not intended to limit the disclosure. Where used herein, the singular forms “a,” “an,” and “the” are intended to include the plural form unless the context clearly indicates otherwise. Where used herein, the terms “comprises” or “comprising” specify the presence of a described feature, integer, step, action, element, or component, but do not exclude the presence or addition of one or more other features, integers, steps, actions, elements, components, or groups thereof. Thus, for example, an article “comprises” or “comprising” components A, B, and C may contain only components A, B, and C, or it may contain components A, B, and C together with one or more other components.

[0098] It is understood that the subject matter may be embodied in many different forms and should not be construed as being limited to the exemplary configurations described herein. Rather, these exemplary configurations are provided to make the subject matter thorough and complete and to convey the disclosure to those skilled in the art. In fact, the subject matter is intended to cover substitutes, modifications, and equivalents of these exemplary configurations that fall within the scope and spirit of the subject matter described herein. Furthermore, specific details are provided in the detailed description of the subject matter to provide a complete understanding of the subject matter. However, it will be apparent to those skilled in the art that the subject matter may be carried out without such specific details.

Claims

1. It is a machine, A centrifugal impeller stage configured to rotate around a rotation axis, the impeller stage having two separate rows of impeller blades, the first row of impeller blades configured to receive a fluid flow in the first axial direction, accelerate the fluid flow in a vector away from the rotation axis, and discharge the fluid flow radially outward to a second row of impeller blades, the second row of impeller blades configured to receive the fluid flow radially outward from the first row of impeller blades, accelerate the fluid flow first in the radially inward direction in a vector toward the rotation axis, and then accelerate the fluid flow in the first axial direction, A diffuser stage around the rotation axis, wherein the diffuser stage has two rows of diffuser blades, the first row of diffuser blades is configured to receive the fluid flow from the impeller stage and first accelerate the fluid flow in the first axial direction, and then accelerate the fluid flow in a vector toward the rotation axis, and the second row of diffuser blades is configured to receive the inward radial fluid flow from the first row of diffuser blades and first accelerate the fluid flow in a vector away from the rotation axis, and then accelerate the fluid flow in the first axial direction, and then discharge the fluid flow from the diffuser stage in the first axial direction, A machine equipped with [the necessary components].

2. The machine according to claim 1, wherein the impeller stage is a first impeller stage, the second row of diffuser blades is configured to discharge the fluid flow from the diffuser stage to the second impeller stage in the first axial direction, the second impeller stage is configured to rotate around the axis of rotation, the second impeller stage has two rows of impeller blades, the first row of impeller blades of the second impeller stage is configured to receive the fluid flow from the diffuser stage, accelerate the fluid flow on a vector away from the axis of rotation, and discharge the fluid flow in the outward radial direction to the second row of impeller blades of the second impeller stage, the second row of impeller blades of the second impeller stage is configured to receive the outward radial fluid flow from the first row of impeller blades of the second impeller stage, first accelerate the fluid flow in the inward radial direction on a vector toward the axis of rotation, and then accelerate the fluid flow in the first axial direction.

3. The machine according to claim 2, wherein the diffuser stage is a first diffuser stage, and the machine further comprises a second diffuser stage around the axis of rotation, the second diffuser stage having two rows of diffuser blades, the first row of diffuser blades of the second diffuser stage configured to receive the fluid flow from the second impeller stage, first accelerating the fluid flow in the first axial direction, and then accelerating the fluid flow in a vector toward the axis of rotation, and the second row of diffuser blades of the second diffuser stage configured to receive the inward radial fluid flow from the first row of diffuser blades of the second diffuser stage, first accelerating the fluid flow in a vector away from the axis of rotation, and then accelerating the fluid flow in the first axial direction, and then discharging the fluid flow from the second diffuser stage in the first axial direction.

4. The machine according to claim 1, wherein each of the impeller stage and the diffuser stage has an outer diameter, and the outer diameter of the impeller stage is not greater than the outer diameter of the diffuser stage.

5. The machine according to claim 4, wherein the outer diameter of the impeller stage is substantially equal to the outer diameter of the diffuser stage.

6. A centrifugal impeller for machinery, The first row of impeller blades is shaped and positioned to receive a fluid flow in the first axial direction, accelerate the fluid flow away from the rotation axis of the impeller, and discharge the fluid flow radially outward toward the second row of impeller blades, The second row of impeller blades is shaped and positioned to receive the outward radial fluid flow from the first row of impeller blades, first accelerating the fluid flow in the inward radial direction along a vector toward the axis of rotation, and then accelerating the fluid flow in the direction of the first axis, A centrifugal impeller equipped with this feature.

7. A diffuser for machinery, A first row of diffuser blades, which are shaped and arranged to receive a fluid flow in the first axial direction, accelerate the fluid flow in the first axial direction, and then accelerate the fluid flow along a vector toward the axis of rotation, The second row of diffuser blades is shaped and positioned to receive the inward radial fluid flow from the first row of diffuser blades, first accelerating the fluid flow in a vector away from the axis of rotation, then accelerating the fluid flow in the direction of the first axis, and then discharge the fluid flow from the diffuser stage in the direction of the first axis, A diffuser equipped with this feature.

8. It is a machine, A centrifugal impeller stage configured to rotate around a rotation axis, the impeller stage having three separate rows of impeller blades, the first row of impeller blades configured to receive a fluid flow in the first axial direction, accelerate the fluid flow on a vector away from the rotation axis, and discharge the fluid flow radially outward to a second row of impeller blades, the second row of impeller blades configured to accelerate the fluid flow radially outward by an impeller radial velocity component and accelerate the fluid flow in the second axial direction by an impeller axial velocity component, the second axial direction being opposite to the first axial direction, and the third row of impeller blades configured to receive the fluid flow radially outward from the second row of impeller blades, first accelerate the fluid flow radially inward on a vector toward the rotation axis, and then accelerate the fluid flow in the first axial direction, A diffuser stage around the rotation axis, wherein the diffuser stage has three rows of diffuser blades, the first row of diffuser blades is configured to receive the fluid flow from the impeller stage and first accelerate the fluid flow in the first axial direction, and then accelerate the fluid flow in a vector toward the rotation axis, the second row of diffuser blades is configured to accelerate the fluid flow in the inward radial direction by the diffuser radial velocity component and in the second axial direction by the diffuser axial velocity component, and the third row of diffuser blades is configured to receive the inward radial fluid flow from the second row of diffuser blades and first accelerate the fluid flow in a vector away from the rotation axis, and then accelerate the fluid flow in the first axial direction, and then discharge the fluid flow from the diffuser stage in the first axial direction, A machine equipped with [the necessary components].

9. The machine according to claim 8, wherein each of the impeller stage and the diffuser stage has an outer diameter, and the outer diameter of the impeller stage is not greater than the outer diameter of the diffuser stage.

10. The machine according to claim 9, wherein the outer diameter of the impeller stage is substantially equal to the outer diameter of the diffuser stage.

11. The impeller stage is the first impeller stage, and the second row of diffuser blades is configured to discharge the fluid flow from the diffuser stage to a second impeller stage which is configured to rotate around the rotation axis in the first axial direction, and the second impeller stage is The first row of impeller blades of the second impeller stage is configured to receive the fluid flow in the first axial direction, accelerate the fluid flow on a vector away from the axis of rotation, and discharge the fluid flow in an outward radial direction to the second row of impeller blades of the second impeller stage, The second row of impeller blades of the second impeller stage is configured to accelerate the fluid flow in the outward radial direction by the impeller radial velocity component of the second impeller stage, and to accelerate the fluid flow in the second axial direction by the impeller axial velocity component of the second impeller stage, The third row of impeller blades of the second impeller stage is configured to receive the outward radial fluid flow from the second row of impeller blades of the second impeller stage, first accelerating the fluid flow in the inward radial direction along a vector toward the axis of rotation, and then accelerating the fluid flow in the first axial direction, The machine according to claim 8, comprising:

12. The diffuser stage is a first diffuser stage, and the machine further comprises a second diffuser stage around the rotating shaft, the second diffuser stage is The first row of diffuser blades of the second diffuser stage is configured to receive the fluid flow from the second impeller stage, first accelerate the fluid flow in the first axial direction, and then accelerate the fluid flow in a vector toward the rotation axis, A second row of diffuser blades of the second diffuser stage, configured to accelerate the fluid flow in the inward radial direction by the diffuser radial velocity component of the second diffuser stage, and to accelerate the fluid flow in the second axial direction by the diffuser axial velocity component of the second diffuser stage; and a third row of diffuser blades of the second diffuser stage, configured to receive the inward radial fluid flow from the second row of diffuser blades of the second diffuser stage, first accelerating the fluid flow on a vector away from the axis of rotation, then accelerating the fluid flow in the first axial direction, and then discharging the fluid flow from the diffuser stage in the first axial direction; The machine according to claim 11, comprising:

13. A centrifugal impeller for machinery, A first row of impeller blades is configured to receive a fluid flow in the first axial direction, accelerate the fluid flow on a vector away from the rotation axis of the impeller, and discharge the fluid flow in an outward radial direction to a second row of impeller blades, The impeller blades are configured such that the fluid flow is accelerated in the outward radial direction by the impeller radial velocity component, and the fluid flow is accelerated in the second axial direction by the impeller axial velocity component, wherein the second axial direction is opposite to the first axial direction, and the second row of impeller blades A third row of impeller blades is configured to receive the outward radial fluid flow from the second row of impeller blades, first accelerating the fluid flow in the inward radial direction along a vector toward the axis of rotation, and then accelerating the fluid flow in the first axial direction, A centrifugal impeller equipped with this feature.

14. A diffuser for machinery, A first row of diffuser blades is configured to receive the fluid flow from the impeller stage, first accelerate the fluid flow in the first axial direction, and then accelerate the fluid flow in a vector toward the rotation axis of the diffuser, The diffuser is configured to accelerate the fluid flow in the inward radial direction by the diffuser radial velocity component, and to accelerate the fluid flow in the second axial direction by the diffuser axial velocity component, wherein the second axial direction is opposite to the first axial direction, and comprises a second row of diffuser blades. A third row of diffuser blades is configured to receive the inward radial fluid flow from the second row of diffuser blades, first accelerate the fluid flow in a vector away from the axis of rotation, then accelerate the fluid flow in the first axial direction, and then discharge the fluid flow from the diffuser stage in the first axial direction, A diffuser equipped with this feature.

15. It is a machine, A centrifugal impeller stage configured to rotate around a rotation axis, the impeller stage having three separate rows of impeller blades, the first row of impeller blades configured to receive an inward radial fluid flow, accelerate the fluid flow first away from the rotation axis and then toward the rotation axis, and discharge the fluid flow outward radially to a second row of impeller blades, the second row of impeller blades configured to accelerate the fluid flow outward radially, and the third row of impeller blades configured to receive the outward radial fluid flow from the second row of impeller blades, accelerate the fluid flow first toward the rotation axis in the inward radial direction, and then accelerate the fluid flow in the forward axial direction and discharge the fluid flow axially, A diffuser stage around the rotation axis, the diffuser stage having two rows of diffuser blades, the first row of diffuser blades configured to receive the fluid flow from the preceding impeller stage, first accelerating the fluid flow in the forward axial direction, and then accelerating the fluid flow toward the rotation axis, the second row of diffuser blades configured to accelerate the fluid flow in the inward radial direction and discharge the fluid flow from the diffuser stage to the subsequent impeller stage, the fluid flow passing through the second row and the third row of impeller blades passing through a fluid channel bounded by the surface of the impeller stage on the first axial side and by the surface of the diffuser stage on the second axial side, A machine equipped with [the necessary components].

16. A reversible pump turbine suitable for installation in vertical wells, It is a multi-stage impeller diffuser, A first impeller stage configured to rotate around a rotation axis, the first impeller stage having two separate rows of impeller blades, the first row of impeller blades configured to receive a fluid flow in a first axial direction, accelerate the fluid flow in a vector away from the rotation axis, and discharge the fluid flow radially outward to a second row of impeller blades, the second row of impeller blades configured to receive the fluid flow radially outward from the first row of impeller blades, accelerate the fluid flow first in a radially inward direction in a vector toward the rotation axis, and then accelerate the fluid flow in the first axial direction, A first diffuser stage around the rotation axis, the first diffuser stage having two rows of diffuser blades, the first row of diffuser blades configured to receive the fluid flow from the impeller stage, first accelerating the fluid flow in the first axial direction, and then accelerating the fluid flow in a vector toward the rotation axis, and the second row of diffuser blades configured to receive the inward radial fluid flow from the first row of diffuser blades, first accelerating the fluid flow in a vector away from the rotation axis, and then accelerating the fluid flow in the first axial direction, and then discharging the fluid flow from the first diffuser stage to the second impeller stage in the first axial direction, The second impeller stage is configured to rotate around the rotation axis and has two rows of impeller blades, wherein the first row of impeller blades of the second impeller stage is configured to receive the fluid flow from the diffuser stage, accelerate the fluid flow in a vector away from the rotation axis, and discharge the fluid flow in the outward radial direction to the second row of impeller blades of the second impeller stage, wherein the second row of impeller blades of the second impeller stage is configured to receive the outward radial fluid flow from the first row of impeller blades of the second impeller stage, accelerate the fluid flow first in the inward radial direction in a vector toward the rotation axis, and then accelerate the fluid flow in the first axial direction, A second diffuser stage having two diffuser blade rows, located around the rotation axis, wherein the first row of diffuser blades of the second diffuser stage is configured to receive the fluid flow from the second impeller stage, first accelerating the fluid flow in the first axial direction, and then accelerating the fluid flow in a vector toward the rotation axis, and the second row of diffuser blades of the second diffuser stage is configured to receive the inward radial fluid flow from the first row of diffuser blades of the second diffuser stage, first accelerating the fluid flow in a vector away from the rotation axis, and then accelerating the fluid flow in the first axial direction, and then discharging the fluid flow from the second diffuser stage in the first axial direction, A multi-stage impeller diffuser having, An annular passage surrounding the multi-stage impeller diffuser in the radial direction, In the pump mode of the reversible pump turbine, a manifold is configured to receive the fluid flow discharged from the annular passage in the second axial direction, the second axial direction being opposite to the first axial direction, and to guide the fluid flow to the first impeller stage in the first axial direction; and in the turbine mode of the reversible pump turbine, a manifold is configured to receive the fluid flow discharged from the first impeller stage in the second axial direction and to guide the fluid flow to the annular passage in the first axial direction. A motor generator coupled to the multi-stage impeller diffuser by an axis, A reversible pump turbine equipped with a reversible pump turbine.

17. The reversible pump turbine according to claim 16, wherein each of the first impeller stage and the first diffuser stage has an outer diameter, and the outer diameter of the first impeller stage is not greater than the outer diameter of the first diffuser stage.

18. The reversible pump turbine according to claim 17, wherein the outer diameter of the first impeller stage is substantially equal to the outer diameter of the first diffuser stage.

19. It is a machine, A first impeller stage is configured to rotate around a rotation axis, receive a fluid flow from a first axial direction, change the direction of the fluid flow through a toroidal fluid channel, and discharge the fluid flow to a first diffuser stage in a second axial direction opposite to the first axial direction, The first diffuser stage is configured to receive the fluid flow from the first impeller stage, accelerate the fluid flow in a vector toward the rotation axis, and then discharge the fluid flow from the first diffuser stage to the second impeller stage in the direction of the second axial direction, A second impeller stage configured to rotate around the rotation axis, the second impeller stage having two separate rows of impeller blades, the first row of impeller blades configured to receive the fluid flow in the second axial direction, accelerate the fluid flow in a vector away from the rotation axis, and discharge the fluid flow radially outward to the second row of impeller blades, the second row of impeller blades configured to receive the fluid flow radially outward from the first row of impeller blades, accelerate the fluid flow first in a radially inward direction toward the rotation axis, and then accelerate the fluid flow in the second axial direction, A second diffuser stage around the rotation axis, the second diffuser stage having two rows of second diffuser blades, the first row of the second diffuser blades configured to receive the fluid flow from the second impeller stage, first accelerating the fluid flow in the second axial direction, and then accelerating the fluid flow in a vector toward the rotation axis, the second row of the second diffuser blades configured to receive the inward radial fluid flow from the first row of the second diffuser blades, first accelerating the fluid flow in a vector away from the rotation axis, and then accelerating the fluid flow in the second axial direction, and then discharging the fluid flow from the second diffuser stage in the second axial direction, A machine equipped with [the necessary components].

20. The machine according to claim 19, wherein the second row of diffuser blades of the second diffuser stage is configured to discharge the fluid flow from the second diffuser stage to the third impeller stage in the second axial direction, the third impeller stage is configured to rotate around the axis of rotation, the third impeller stage has two rows of impeller blades, the first row of impeller blades of the third impeller stage is configured to receive the fluid flow from the second diffuser stage, accelerate the fluid flow in a vector away from the axis of rotation, and discharge the fluid flow in the outward radial direction to the second row of impeller blades of the third impeller stage, the second row of impeller blades of the third impeller stage is configured to receive the outward radial fluid flow from the first row of impeller blades of the third impeller stage, first accelerate the fluid flow in the inward radial direction in a vector toward the axis of rotation, and then accelerate the fluid flow in the second axial direction.

21. The machine according to claim 20, further comprising a third diffuser stage around the rotation axis, the third diffuser stage having two rows of diffuser blades, the first row of diffuser blades of the third diffuser stage being configured to receive the fluid flow from the third impeller stage, first accelerating the fluid flow in the second axial direction, and then accelerating the fluid flow in a vector toward the rotation axis, the second row of diffuser blades of the third diffuser stage being configured to receive the inward radial fluid flow from the first row of diffuser blades of the third diffuser stage, first accelerating the fluid flow in a vector away from the rotation axis, and then accelerating the fluid flow in the second axial direction, and then discharging the fluid flow from the third diffuser stage in the second axial direction.

22. The machine according to claim 19, wherein each of the second impeller stage and the second diffuser stage has an outer diameter, and the outer diameter of the second impeller stage is not greater than the outer diameter of the second diffuser stage.

23. The machine according to claim 22, wherein the outer diameter of the second impeller stage is substantially equal to the outer diameter of the second diffuser stage.

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