pump

Abstract

The present invention provides a pump that can suppress the increase in shaft power during shut-off operation when fluid flows back from the impeller inlet, and can suppress the generation of underwater vortices and air intake vortices and eliminate vortices when pumping water (when not in shut-off operation). [Solution] In this pump 100, the vortex suppression section 2 includes a central member 22 located in the center of the suction port when viewed from above, and a plurality of flow straightening partition plates 23 that have width in the vertical direction and connect a plurality of column members 21 and the central member 22.

Description

Technical Field

[0001] The present invention relates to a pump, and particularly to a pump provided with a vortex suppression portion.

Background Art

[0002] Conventionally, a pump provided with a vortex suppression portion has been known (see, for example, Patent Document 1).

[0003] In Patent Document 1, a pump disposed in a suction water tank and provided with a vortex suppression portion is disclosed. In Patent Document 1, the vortex suppression portion includes a suction bell having a suction port and a cross-shaped baffle plate positioned below the suction bell. In Patent Document 1, by operating the pump, the fluid in the suction water tank flows into the pump from the suction port of the suction bell. Further, in Patent Document 1, while the pump is operating, underwater vortices and air suction vortices are generated in the suction water tank, and when the underwater vortices and air suction vortices are sucked into the pump from the suction port, intense vibration and loud noise are generated during the operation of the pump, so the generation of vortices is suppressed by the baffle plate. Here, an underwater vortex is a vortex in which the pressure of the vortex flow drops below the vapor pressure from the bottom surface and side surface of the suction water tank in which the pump is disposed and is sucked into the suction port. Further, an air suction vortex is a vortex in which the vortex flow sucks air on the water surface (while entraining) and is sucked into the suction port from the water surface toward the suction port.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Although not disclosed in Patent Document 1 mentioned above, when a pump is shut off and operated in a shut-off state, the fluid flows backward towards the suction port while swirling. However, if a baffle plate is provided on the pump, the baffle plate acts as resistance and weakens the swirling, which can cause the shut-off shaft power to become excessively large. Therefore, there is a need to suppress the excessive increase in the shut-off shaft power.

[0006] This invention was made to solve the above-mentioned problems, and one of its objectives is to provide a pump that can suppress the increase in shaft power during shut-off operation when fluid flows back from the impeller inlet, and that can suppress the generation of underwater vortices and air intake vortices and eliminate vortices when pumping water (when not in shut-off operation). [Means for solving the problem]

[0007] To achieve the above objective, a pump in one aspect of this invention is a pump arranged in a suction tank and comprises: a suction port forming section having a suction port opening downward at its lower end; a pump casing in which an impeller is arranged and connected to the suction port forming section; and a vortex suppression section arranged below the suction port forming section, wherein the vortex suppression section includes a plurality of columnar members extending in the vertical direction and arranged along the lower end of the suction port forming section; a central member located in the center of the suction port in a top view; and a plurality of flow straightening partition plates arranged in the vertical direction and connecting the plurality of columnar members and the central member.

[0008] In a pump according to one aspect of this invention, as described above, the vortex suppression section includes a plurality of columnar members extending vertically and arranged along the lower end of the suction port forming section, and a plurality of flow-straightening partition plates arranged vertically and connecting the plurality of columnar members and the central member. As a result, fluid flows vertically along the flow-straightening partition plates, and the flow-straightening action can suppress the generation of underwater vortices from the bottom surface of the suction tank below the pump. In addition, by providing flow-straightening partition plates, if underwater vortices are generated laterally, they can be brought into contact with the flow-straightening partition plates and eliminated. Furthermore, by providing both columnar members and flow-straightening partition plates, if air intake vortices are generated from the water surface, the air intake vortices entering the suction port provided in the suction port forming section can be brought into contact with the columnar members and flow-straightening partition plates and eliminated. In addition, by providing a central member, flow-straightening partition plates are not provided in the central part, which suppresses an excessive amount of resistance to the swirling fluid during backflow and suppresses an increase in shutoff shaft power. As a result, it is possible to suppress the increase in shaft power during shut-off operation when fluid flows back from the impeller inlet, and to suppress the generation of underwater vortices and air intake vortices and eliminate vortices when pumping water (when not in shut-off operation).

[0009] In the pump according to the first aspect described above, preferably, the vortex suppression section is annular in top view and includes a plurality of annular plate members connected to each other by a column member. With this configuration, the flow from the side of the pump toward the center can be straightened by the annular plate members in the circumferential direction of the pump, thereby suppressing the generation of underwater vortices from the side walls on the sides and eliminating air intake vortices generated from the water surface by contact with them.

[0010] In the pump according to the first aspect described above, preferably, the central member protrudes upward toward the suction port, and the vertical width of the multiple flow-rectifying partition plates on the column member side is smaller than the protruding height of the central member when viewed from the side. With this configuration, the protruding central member allows the fluid to flow along the central member from below toward the suction port. Furthermore, because the vertical width of the multiple flow-rectifying partition plates on the column member side is smaller than the protruding height of the central member when viewed from the side, the portion that resists the swirling of the fluid in the event of backflow can be reduced, thereby suppressing an increase in shutoff shaft power.

[0011] In this case, preferably, the multiple flow-rectifying partition plates have, in a side view, a central partition portion connected to the central member, a column member-side partition portion smaller than the protruding height of the central member and located on the column member side, and an inclined portion that slopes downward toward the column member-side partition portion connecting the central partition portion and the column member-side partition portion. With this configuration, the vertical width of the flow-rectifying partition plate can be gradually reduced toward the column member side by the inclined portion. As a result, the generation of underwater vortices below the pump can be suppressed by the central partition portion, which has a large vertical width, while the portion that resists swirling can be reduced by the column member-side partition portion, which has a small vertical width.

[0012] In the pump according to the first aspect described above, preferably, the multiple flow-rectifying partition plates are arranged at predetermined angular intervals along the outer circumferential surface of the central member. With this configuration, since the multiple flow-rectifying partition plates are arranged at equal intervals, the fluid flowing from the bottom to the top of the pump can be rectified without bias, and the generation of underwater vortices at the bottom can be effectively suppressed.

[0013] In this case, preferably, the central member has a cylindrical shape. With this configuration, the fluid can flow from bottom to top through through holes formed inside the central member, thus reducing the portion that creates fluid resistance. Furthermore, because the central member has a cylindrical shape, it can be easily constructed by using a cylindrical member including a pipe, and the vortex suppression part can be made lighter.

[0014] In the configuration described above, where the central member has a cylindrical shape, the central member further includes a lid that closes the opening at the top of the central member. With this configuration, the inclusion of the lid can suppress the pump from sucking in underwater vortices generated below.

[0015] In the configuration described above, the central member is provided with a cover portion that closes the opening at the top of the central member. Preferably, in a top view, the diameter of the central member is 10% to 50% of the impeller inlet diameter. With this configuration, by keeping the size of the central member within a certain range, it is possible to prevent it from becoming a resistance to rotation during shut-off operation (backflow), thereby suppressing an increase in shut-off shaft power and preventing increased resistance when fluid flows into the impeller during pumping (when not in shut-off operation). In addition, by keeping the diameter of the central member within a certain range, fluid can flow in from below, so the effect of the flow straightening partition plate can be maintained without excessively reducing the suction performance. Therefore, it is possible to suppress the generation of underwater vortices while the cover portion suppresses the suction of underwater vortices generated below the pump.

[0016] In the pump according to the first aspect described above, preferably, the vortex suppression section is provided on a plurality of column members and further includes a plurality of flow-straightening ribs that protrude from each of the plurality of column members toward the central member and extend along the vertical direction. With this configuration, by providing flow-straightening ribs that extend along the vertical direction, the fluid flowing in from the side can be straightened over a wide area in the vertical direction, thereby effectively suppressing the generation of underwater vortices and air intake vortices from the water surface on the side of the pump. In addition, underwater vortices and air intake vortices entering the pump intake from the side can be eliminated by bringing them into contact with the flow-straightening ribs or column members.

[0017] In the configuration in which the vortex suppression section includes a plurality of annular plate members, preferably, an inflow suppression plate is further included, positioned downstream of the annular plate member on the side facing the side of the suction tank, so as to cover the gap between the annular plate members in the vertical direction. With this configuration, by covering the gap of the downstream annular plate member with a plurality of inflow suppression plates, the flow that circulates downstream of the pump is reduced, and air intake vortices generated from the water surface downstream of the suction tank and underwater vortices generated downstream can be suppressed. Furthermore, if an air intake vortex occurs, it can be eliminated by contact with the inflow suppression plate. Moreover, by providing the inflow suppression plate, air intake vortices from the side can be guided by the inflow flow to the annular plate member in the gap between the inflow suppression plates, so that the air intake vortex can be eliminated by contact with the annular plate member, and the generation of underwater vortices can be suppressed by the rectification of the flow by the annular plate member.

[0018] In the configuration in which the vortex suppression section includes a plurality of annular plate members, preferably, the uppermost of the plurality of annular plate members is attached to the suction port forming section and has a vortex suppression wall portion that is provided on at least a part of the outer circumference located on the downstream side in the direction of fluid flow inside the suction water tank and protrudes upward from the outer circumference. With this configuration, the air suction vortex generated on the downstream side of the suction water tank can be eliminated by bringing it into contact with the vortex suppression wall portion.

[0019] In the pump according to the above first aspect, preferably, it further includes a plate-like member attached to the outer peripheral surface and extending in the vertical direction, and the lower end portion of the plate-like member is located above the upper end portion of the vortex suppression portion. With this configuration, the air suction vortex generated above the vortex suppression portion can be brought into contact with the plate-like member and eliminated.

Effects of the Invention

[0020] According to the present invention, it is possible to suppress an increase in the axial power during cut-off operation when fluid flows backward from the impeller inlet as described above, and it is possible to provide a pump capable of suppressing the generation of underwater vortices and air suction vortices and eliminating the vortices when pumping water (when it is not a cut-off operation).

Brief Description of the Drawings

[0021] [Figure 1] It is a schematic diagram showing the overall configuration of the pump according to the first embodiment. [Figure 2] It is a front view of the vortex suppression portion according to the first embodiment. [Figure 3] It is a top view of the vortex suppression portion according to the first embodiment. [Figure 4] It is a perspective view of the vortex suppression portion according to the first embodiment. [Figure 5] It is a graph showing the relationship between the flow rate, the total head, and the pump efficiency in the pump with a vortex suppression portion of the present invention and the pump without a vortex suppression portion of the comparative example. [Figure 6] It is a graph showing the relationship between the flow rate and the cut-off axial power in the pump with a vortex suppression portion of the present invention and the pump without a vortex suppression portion of the comparative example. <00――――095>It is a schematic diagram showing the overall configuration of the pumps according to the second and third embodiments. [Figure 8] It is a side view of the vortex suppression portion according to the second embodiment. [Figure 9] It is a cross-sectional view taken along line IX-IX of FIG. 8. [Figure 10] It is a perspective view of the vortex suppression portion according to the second embodiment. [Figure 11] This is a side view of the vortex suppression unit according to the third embodiment. [Figure 12] This is a perspective view of the vortex suppression unit according to the third embodiment. [Figure 13] This is a schematic diagram showing the overall configuration of the pump according to the fourth embodiment. [Figure 14] This is a perspective view of the vortex suppression section using a modified example. [Figure 15] This is a perspective view of another vortex suppression section with modified examples. [Modes for carrying out the invention]

[0022] The embodiments will be described below with reference to the drawings.

[0023] [First Embodiment] (Pump configuration) The pump of the first embodiment will be described with reference to Figures 1 to 4.

[0024] The pump 100 shown in Figure 1 comprises a pump body 1 and a vortex suppression unit 2. The pump 100 of the first embodiment is a vertical-axis mixed-flow pump in which the rotation axis α of the rotating shaft 12 that rotates the impeller 11 extends in the vertical direction. The pump 100 of the first embodiment is a water pump that is placed in a suction tank 50 and pumps up fluid L. The pump 100 is installed near at least one of the multiple sides W of the suction tank 50. When the fluid L is pumped up by the pump 100, it flows from the side where the fluid is supplied to the suction tank 50 (upstream side) to the pump 100 side (downstream side). The fluid L is, for example, water. Here, in the drawing, the upper side is the Z1 side, the lower side is the Z2 side, and the vertical direction is the Z direction. The radial direction intersecting the Z direction is the R direction.

[0025] The pump body 1 extends vertically. The pump body 1 has a suction port forming section 10 at its lower end. The suction port forming section 10 has an opening at its lower end that opens downwards. The suction port forming section 10 is annular when viewed from above. The suction port forming section 10 is configured to allow fluid L to flow in from below.

[0026] The pump body 1 is provided with a discharge port 14 at the top, to which a discharge pipe is attached. By connecting the discharge pipe to the discharge port 14 and establishing communication, the fluid L that flows in from the suction port of the suction port forming section 10 is discharged to the outside. The discharge pipe is also provided with an adjustment part such as a valve. When the adjustment part is in the open position, the fluid L is discharged from the pump 100. When the pump 100 is not in use, the adjustment part is closed.

[0027] The pump body 1 includes a pump casing 1a that houses an impeller 11. Inside the pump 100, there is a flow path through which a fluid L flows from the suction port to the discharge port 14. The impeller 11 is located within the flow path and is configured to rotate to draw the fluid L into the pump 100 from the suction port and direct the fluid L toward the discharge port 14. The center of the suction port coincides with the rotation center of the impeller 11 in the vertical direction and is located on the rotation axis α. The pump casing 1a and the suction port forming section 10 are fixed together, for example, by bolting or welding.

[0028] The impeller 11 is fixed below the rotating shaft 12, which extends in the vertical direction. The upper end of the rotating shaft 12 is connected to the drive unit 13, and the lower end of the rotating shaft 12 is connected to the impeller 11. The impeller 11 is configured to rotate as the rotating shaft 12 rotates due to the drive unit 13. The impeller 11 has a plurality of blades 11a. The drive unit 13 can be, for example, a motor or an engine. The drive unit may also be configured to include a reduction gear or the like.

[0029] The vortex suppression section 2 is located below the intake port forming section 10. More specifically, the vortex suppression section 2 is attached to the lower end of the intake port forming section 10. Fluid L flows into the vortex suppression section 2 from below and from the side.

[0030] As shown in Figure 2, the vortex suppression section 2 includes a column member 21, a central member 22, a plurality of flow straightening partition plates 23, an annular plate member 24, and flow straightening rib sections 25.

[0031] As shown in Figures 3 and 4, the column member 21 is configured to extend in the vertical direction. The column member 21 is configured to connect a plurality of annular plate members 24 arranged along the vertical direction. Specifically, the column member 21 is attached to the lower surface of the annular plate member 24 located at the uppermost end and the upper surface of the annular plate member 24 located at the lowermost end, and is configured to contact from the radial direction a recess 24a provided in the annular plate member 24 located between the uppermost and lowermost annular plate member 24, which is recessed from the radially inner to the radially outer. (It is fitted into the recess 24a). Multiple column members 21 are arranged along the circumferential direction of the annular plate member 24. For example, the multiple column members 21 are arranged at equal angular intervals of 45 degrees in the circumferential direction when viewed from above. That is, for example, eight column members 21 are provided. A fluid L flows through the gaps in the circumferential direction between the multiple column members 21 arranged along the circumferential direction. For example, the column member 21 has an annular shape when viewed from above. As another example, the column member 21 has a polygonal shape when viewed from above. The column member 21 is arranged along the lower end of the suction port forming section 10 that forms the suction port. Multiple column members 21 are arranged vertically along the lower end of the suction port forming section 10. The column members 21 may be arranged along the Z direction, or they may be inclined with respect to the Z direction. Also, the column members 21 are arranged so as not to protrude downward from the lowest annular plate member 24. The diameter d4 of the column member 21 is formed to be, for example, 0.08 times or more and 0.125 times or less the impeller inlet diameter d1 (diameter of the impeller inlet). The impeller inlet diameter d1 refers to the diameter of the portion enclosed by the pump casing 1a (impeller inlet) at the position where the fluid L flowing in from the suction port contacts the lower end of the impeller 11.

[0032] As shown in Figures 1 and 2, the suction port forming section 10 is, for example, a bell mouth. The suction port formed by the suction port forming section 10 is formed in a so-called bell mouth shape, with the diameter increasing towards the bottom.

[0033] As shown in Figure 1, the central member 22 is cylindrical in shape. The central member 22 is located in the center of the suction port when viewed from above. The central member 22 is also located in the center of the annular plate member 24 when viewed from above. The center includes the center and its periphery. For example, the center of the suction port and the center of the annular plate member 24 overlap when viewed from above. If multiple annular plate members 24 are arranged along the vertical direction, the central member 22 is located at least on the annular plate member 24 furthest from the suction port (located at the bottom). The central member 22 is formed, for example, by a pipe.

[0034] As shown in Figures 1 and 2, the central member 22 is configured to protrude upward toward the intake port. In a top view, the diameter (outer diameter) d3 of the central member 22 is preferably 10% to 50% (0.1 to 0.5 times) the impeller inlet diameter d1, and more preferably 0.15 to 0.3 times.

[0035] The outer diameter (diameter) d2 of the suction port forming section 10 is formed to be, for example, 1.5 times or more and 2.2 times or less the impeller inlet diameter d1. Each column member 21 is arranged at equal intervals along the suction diameter of the suction port (suction port forming section 10).

[0036] As shown in Figure 2, in the first embodiment, the central member 22 is fitted with a cover portion 22a that closes the upper opening. The cover portion 22a is positioned so as not to protrude vertically from the end of the central member 22 that forms the opening. In the first embodiment, the cover portion 22a is provided to close the entire opening. In another example, the cover portion 22a is provided to close a part of the opening.

[0037] As shown in Figure 4, the multiple flow-rectifying partition plates 23 are arranged in the vertical direction. The multiple flow-rectifying partition plates 23 are configured to connect the multiple column members 21 and the central member 22. The multiple flow-rectifying partition plates 23 are configured to rectify the flow of fluid L flowing in from below. In detail, the fluid L is rectified as it flows vertically along the multiple flow-rectifying partition plates 23. The multiple flow-rectifying partition plates 23 are not provided in the central portion. The multiple flow-rectifying partition plates 23 are connected to the outer circumferential surface of the central member 22 from the side. The multiple flow-rectifying partition plates 23 are arranged at predetermined angular intervals along the outer circumferential surface of the central member 22. As an example, eight flow-rectifying partition plates 23 are provided, and the predetermined angular interval is 45 degrees, which is 360 degrees divided by 8. In short, the multiple flow-rectifying partition plates 23 extend radially from the central member 22 when viewed from above. Each of the multiple flow-rectifying partition plates 23 is positioned in the circumferential direction at a location corresponding to the column member 21.

[0038] Each of the multiple rectifying partition plates 23 has a central partition portion 23a, a column member side partition portion 23b, and an inclined portion 23c. The central partition portion 23a is located on the central member 22 side and is configured to connect to the central member 22. The column member side partition portion 23b is located on the column member 21 side of the central partition portion 23a. In other words, it is located radially outward. The inclined portion 23c is configured to connect the radially inward central partition portion 23a and the radially outward column member side partition portion 23b. Furthermore, the inclined portion 23c is configured to incline downward from the central partition portion 23a toward the column member side partition portion 23b (radially outward).

[0039] The multiple flow-rectifying partition plates 23 are formed so that the vertical width on the column member side (width h2 of the column member side partition portion 23b) is smaller than the protruding height of the central member 22. The vertical width h2 of the column member side partition portion 23b (see Figure 2) is formed to be smaller than the height h1 of the central side partition portion 23a (see Figure 2) in a side view. The height h1 of the central side partition portion 23a is set, for example, to 0.12 times or more and 0.3 times or less the impeller inlet diameter d1. The height h2 of the column member side partition portion 23b is set, for example, to 0.12 times or more and 0.18 times or less the impeller inlet diameter d1. Because the vertical length of the column member side partition portion 23b is smaller than that of the central member 22, when the discharge side of the pump is closed and shut off, it does not create resistance and does not excessively weaken the swirling of the backflowing fluid. The height h1 of the central partition portion 23a is the same as the sum of the protruding height of the central member 22 and the vertical thickness of the lid portion 22a. The distance h7 from the upper end surface of the central partition portion 23a to the lowest end of the impeller 11 is, for example, 0.9 times or more the impeller inlet diameter d1. Also, the radial length r2 from the center of the central member 22 to the boundary between the central partition portion 23a and the inclined portion 23c is, for example, 0.1 times or more and 0.35 times or less the impeller inlet diameter d1. As another example, if the diameter of the central member 22 is 50% of the impeller inlet diameter, the central partition portion 23a may not be provided, in which case the radial length r2 from the center of the central member 22 to the boundary between the central partition portion 23a and the inclined portion 23c is 0.

[0040] Furthermore, the distance h3 from the lowest end of the impeller 11 to the lowest end of the suction port forming section 10 is formed to be, for example, 0.75 times or less the impeller inlet diameter d1. Also, the distance h4 from the lowest end of the suction port forming section 10 to the bottom surface of the suction water tank 50 is formed to be, for example, 0.7 times or more the impeller inlet diameter d1.

[0041] As shown in Figures 3 and 4, the annular plate member 24 is annular in top view. Annular includes cases where it is circular in top view and cases where it is not circular in top view. In the first embodiment, the annular plate member 24 is a circular annular shape in top view. Multiple annular plate members 24 are arranged in a vertical direction. In the first embodiment, there are three annular plate members 24. A circumferential gap is formed between the multiple annular plate members 24 arranged in a vertical direction. The circumferential gap is further partitioned by the column member 21. The uppermost annular plate member 24 of the multiple annular plate members 24 is connected to the suction port forming section 10. Furthermore, an opening provided in the uppermost annular plate member 24 communicates with the opening of the suction port forming section 10. The annular plate member 24 is configured to rectify the fluid L flowing in from the side. Specifically, the fluid L is rectified as it flows along the annular plate member 24. The lowest annular plate member 24, which faces the bottom surface of the suction tank 50 where the pump 100 is located, is positioned at a predetermined distance h6 from the bottom surface of the suction tank 50 where the pump 100 is located. The predetermined distance h6 is, for example, 0.6 times or less the impeller inlet diameter d1 (see Figure 1). The distance h5 from the upper end surface of the uppermost annular plate member 24 to the lower end surface of the lowest annular plate member 24 is set, for example, to 0.4 times or more and 1 time or less the impeller inlet diameter d1.

[0042] The flow-rectifying rib portion 25 is provided on each of the multiple column members 21. The distance (radial length) r1 from the center of the central member 22 to the inner circumferential surface of the flow-rectifying rib portion 25 is, for example, 0.55 times the impeller inlet diameter d1. The flow-rectifying rib portion 25 is configured to protrude from each of the multiple column members 21 toward the central member 22. The flow-rectifying rib portion 25 is configured to extend vertically, similar to the column members 21. By flowing fluid L along the flow-rectifying rib portion 25, the fluid L flowing in from the side is rectified over a wide area in the vertical direction to suppress the generation of vortices, and any generated vortices are eliminated by contact. The flow-rectifying rib portion 25 is connected to the upper surface of the end of the flow-rectifying partition plate 23 on the column member 21 side. As an example, the flow-rectifying rib portion 25 and the flow-rectifying partition plate 23 are formed as separate components. As another example, the flow-rectifying rib section 25 and the flow-rectifying partition plate 23 are formed as a single unit. Near the impeller inlet radius d1 / 2, the reverse flow swirling speed is large. Therefore, if the flow-rectifying rib section 25 is positioned inside the impeller inlet radius d1 / 2, the distance r1 from the center of the central member 22 to the inner surface of the flow-rectifying rib section 25 becomes a resistance that weakens the flow swirling speed. Also, the wider the flow-rectifying rib section 25, the greater the resistance (swirling stopper). Therefore, by setting the radial length r1 from the center of the central member 22 to the inner surface of the flow-rectifying rib section 25 and preventing the radial width from becoming too large, the swirling is not excessively weakened, and thus the shut-off shaft power does not increase.

[0043] The vortex suppression unit 2 is used to rectify the fluid L to suppress the generation of vortices and to eliminate any vortices that have been generated by contact. The vortices include underwater vortices that are generated below the pump 100 and in the water, and air intake vortices that are generated to the side of the pump 100 and from the water surface, and that entrain air.

[0044] The vortex suppression section 2 is configured to suppress the generation of vortices by straightening the fluid flowing in from below using a flow straightening partition plate 23. Specifically, the fluid L is straightened by flowing vertically along the flow straightening partition plate 23 and the central member 22, thereby suppressing underwater vortices. The flow straightening effect of the flow straightening partition plate 23 is greatest in the central partition portion 23a, which has the greatest vertical height, followed by the inclined portion 23c and the column member side partition portion 23b, in that order. However, even though the flow straightening effect for vortex suppression decreases in the inclined portion 23c and the column member side partition portion 23b, the vortex suppression effect is maintained. On the other hand, when the shut-off operation is performed, and the fluid flows backward while swirling toward the intake, the swirling speed of the backward flow is weaker towards the center of the impeller and is strongest near the impeller inlet. Therefore, the flow straightening partition plate 23 can avoid excessively weakening the swirling. In addition, the annular plate member 24 provides little resistance to the swirling during backward flow and complements the flow straightening effect of the column member side partition portion 23b, thus maintaining the effect of suppressing underwater vortices.

[0045] Furthermore, the vortex suppression section 2 can straighten the flow from the side of the pump 100 toward the center using the annular plate member 24, thereby suppressing the generation of air intake vortices originating from the water surface and eliminating any generated air intake vortices by contact with them. Because the annular plate member 24 can straighten the flow from the side of the pump 100 toward the center, it can suppress the generation of underwater vortices from the side walls on the sides, and the underwater vortices generated below the vortex suppression section 2 are eliminated when they come into contact with (collide with) the annular plate member 24. The flow straightening rib section 25 protrudes from the column member 21 toward the center, so it can straighten the fluid L coming from the side. Therefore, the flow straightening rib section 25 can also suppress the generation of underwater vortices and air intake vortices on the sides. In addition, the vortex suppression section 2 is configured to eliminate vortices when underwater vortices and air intake vortices generated on the sides come into contact with the flow straightening partition plate 23 and the flow straightening rib section 25.

[0046] The vortex suppression section 2 is configured to prevent excessive stopping of the swirling of the fluid L during backflow. Backflow occurs, for example, when the adjustment section provided at the discharge port for discharging the fluid L is closed, preventing the fluid L from being discharged from the pump 100, and the impeller 11 rotates to cause this backflow. When pumping water (not in shut-off operation), the vortex suppression effect is enhanced if the overall vertical height of the flow straightening partition plate 23 is the same as the vertical protrusion height of the central member 22. However, this increases the resistance to weakening the swirling during backflow that occurs in shut-off operation, thus increasing the shut-off shaft power. Therefore, the vertical height of the flow straightening partition plate 23 is adjusted to reduce the portion that acts as resistance to weakening the swirling. In this case, the larger the diameter of the central member 22 (the larger the ratio of the size of the central member 22 to the impeller inlet diameter), the smaller the proportion of the central partition section 23a. For example, if the diameter of the central member 22 is 50% of the impeller inlet diameter, the central partition portion 23a may not be provided, and the inclined portion 23c may be connected to the central member 22. This prevents an excessive amount of resistance that weakens the rotation, and thus suppresses an increase in the shut-off shaft power.

[0047] Figure 5 is a graph showing the relationship between total head, flow rate, and pump efficiency. In Figure 5, total head and pump efficiency are plotted on the vertical axis, and flow rate is plotted on the horizontal axis. In Figure 5, the black-filled triangles represent the relationship between total head and flow rate in the pump 100 equipped with the vortex suppression unit 2 of the present invention (with vortex suppression unit), while the white-outlined triangles represent the relationship between total head and flow rate in the comparative example pump without the vortex suppression unit (without vortex suppression unit). The black-filled circles represent the relationship between flow rate and pump efficiency in the pump 100 equipped with the vortex suppression unit 2 of the present invention (with vortex suppression unit), while the white-outlined circles represent the relationship between flow rate and pump efficiency in the comparative example pump without the vortex suppression unit (without vortex suppression unit). Regarding pump efficiency, there was almost no difference between the pump with and without the vortex suppression unit. Furthermore, in the flow rate range near the point of maximum efficiency, the total head did not change even when the vortex suppression unit of the present invention was provided, compared to when it was not provided.

[0048] Figure 6 is a graph showing the relationship between flow rate and shaft power. In Figure 6, shaft power is plotted on the vertical axis and flow rate is plotted on the horizontal axis. The black square graph shows the relationship between flow rate and shaft power in a pump 100 equipped with the vortex suppression unit 2 of the present invention (with vortex suppression unit), while the white square graph shows the relationship between flow rate and shaft power in a comparative example pump without the vortex suppression unit (without vortex suppression unit). As shown in Figure 6, the shut-off shaft power (shaft power at the flow rate of 0) hardly changed between the pump with and without the vortex suppression unit. Furthermore, while the shut-off shaft power may increase when a conventional vortex suppression unit is installed, in the case of the vortex suppression unit of the present invention, there was no increase in the shut-off shaft power and the maximum shaft power did not increase. From the above, it was found that even when the vortex suppression unit 2 of the present invention is installed in the pump 100, there is no significant change in the efficiency of the pump 100 and the shut-off shaft power does not increase.

[0049] (Effects of the first embodiment) In the first embodiment, the following effects can be obtained.

[0050] In the first embodiment, as described above, the vortex suppression unit 2 includes a plurality of column members 21 that extend vertically and are arranged along the lower end of the suction port forming unit 10, and a plurality of flow straightening partition plates 23 that are arranged vertically and connect the plurality of column members 21 and the central member 22. As a result, fluid flows vertically along the flow straightening partition plates 23, and the generation of underwater vortices from the bottom surface of the suction tank 50 below the pump can be suppressed by the flow straightening effect. In addition, by providing the flow straightening partition plates 23, if an underwater vortex is generated to the side, the underwater vortex can be brought into contact with the flow straightening partition plates 23 and eliminated. Furthermore, by providing both the column members 21 and the flow straightening partition plates 23, if an air intake vortex is generated from the water surface, the air intake vortex entering the suction port provided in the suction port forming unit 10 can be brought into contact with the column members 21 and the flow straightening partition plates 23 and eliminated. Furthermore, by providing the central member 22, a flow-rectifying partition plate 23 is not provided in the central part, thus suppressing an excessive amount of resistance to the swirling fluid during reverse flow and suppressing an increase in shutoff shaft power. As a result, it is possible to suppress the increase in shaft power during shutoff operation when fluid flows back from the impeller inlet, and to suppress the generation of underwater vortices and air intake vortices and eliminate vortices when pumping water (when not in shutoff operation).

[0051] In the first embodiment, as described above, the vortex suppression section 2 is annular in top view and includes a plurality of annular plate members 24 connected to each other by a column member 21. As a result, in the circumferential direction of the pump 100, the flow from the side of the pump 100 toward the center can be straightened by the annular plate members 24, thereby suppressing the generation of underwater vortices from the side walls on the sides and eliminating air intake vortices that originate from the water surface.

[0052] In the first embodiment, as described above, the central member 22 protrudes upward toward the intake port, and the vertical width of the multiple flow-rectifying partition plates 23 on the column member 21 side is smaller than the protruding height of the central member 22 when viewed from the side. As a result, the protruding central member 22 allows the fluid to flow along the central member 22 from below toward the intake port. Furthermore, because the vertical width of the multiple flow-rectifying partition plates 23 on the column member 21 side is smaller than the protruding height of the central member 22 when viewed from the side, the portion that resists fluid swirling in the event of reverse flow can be reduced, thereby suppressing an increase in shutoff shaft power.

[0053] In the first embodiment, as described above, the multiple flow-rectifying partition plates 23, in a side view, have a central partition portion 23a connected to the central member 22, a column member-side partition portion 23b that is smaller than the protruding height of the central member 22 and located on the column member 21 side, and an inclined portion 23c that connects the central partition portion 23a and the column member-side partition portion 23b and slopes downward toward the column member-side partition portion 23b. As a result, the inclined portion 23c makes it possible to gradually reduce the vertical width of the flow-rectifying partition plate 23 toward the column member 21 side. Therefore, the central partition portion 23a, which has a large vertical width, suppresses the generation of underwater vortices below the pump 100, while the column member-side partition portion 23b, which has a small vertical width, reduces the portion that resists swirling.

[0054] In the first embodiment, as described above, the multiple flow-rectifying partition plates 23 are arranged at predetermined angular intervals along the outer circumferential surface of the central member 22. As a result, since the multiple flow-rectifying partition plates 23 are arranged at equal intervals, the fluid flowing from below to above the pump 100 can be rectified without bias, effectively suppressing the generation of underwater vortices below.

[0055] In the first embodiment, as described above, the central member 22 has a cylindrical shape. This allows the fluid L to flow from bottom to top through through holes formed inside the central member 22, thereby reducing the portion that resists the fluid L. Furthermore, because the central member 22 has a cylindrical shape, it can be easily constructed by using a cylindrical member including a pipe, and the vortex suppression section 2 can be made lighter.

[0056] In the first embodiment, as described above, the central member 22 is further provided with a cover portion 22a that closes the opening above the central member 22. By providing the cover portion 22a, it is possible to suppress the pump from sucking in underwater vortices generated below.

[0057] In the first embodiment, as described above, the diameter of the central member 22 in a top view is 10% to 50% of the impeller inlet diameter. By keeping the size of the central member 22 within a certain range, it is possible to prevent it from becoming a resistance to rotation during shut-off operation (backflow), thereby suppressing an increase in shut-off shaft power and preventing increased resistance when fluid flows into the impeller 11 during pumping (when not in shut-off operation). In addition, by keeping the diameter of the central member 22 within a certain range, fluid can flow in from below, so the effect of the flow straightening partition plate 23 can be maintained without excessively reducing the suction performance. Therefore, it is possible to suppress the generation of underwater vortices while suppressing the suction of underwater vortices generated below the pump 100 by the lid portion 22a.

[0058] In the first embodiment, as described above, the vortex suppression section 2 is provided on a plurality of column members 21 and further includes a plurality of flow-straightening rib sections 25 that protrude from each of the plurality of column members 21 toward the central member 22 and extend along the vertical direction. As a result, by providing flow-straightening rib sections 25 that extend along the vertical direction, the fluid flowing in from the side can be straightened over a wide area in the vertical direction, thereby effectively suppressing the generation of underwater vortices and air intake vortices from the water surface on the side of the pump. Furthermore, underwater vortices and air intake vortices entering the pump intake from the side can be eliminated by bringing them into contact with the flow-straightening rib sections 25 or the column members 21.

[0059] [Second Embodiment] Next, the configuration of the pump 200 according to the second embodiment of the present invention will be described with reference to Figures 7 to 10. Unlike the first embodiment, in the second embodiment, the vortex suppression unit 2 includes a plurality of inflow suppression plates 26.

[0060] As shown in Figure 7, in the second embodiment, the central member 22 does not have a lid. Therefore, the central member 22 has a through hole that extends in the vertical direction. The through hole also serves as a flow path for the fluid L.

[0061] As shown in Figures 8, 9, and 10, the multiple inflow suppression plates 26 are configured to extend along the vertical direction. The multiple inflow suppression plates 26 are plate members arranged along the circumferential direction of the annular plate member 24 in a top view. The multiple inflow suppression plates 26 are configured to suppress the flow of fluid L from the side. The multiple inflow suppression plates 26 are arranged to cover more than half of the circumferential gap S between the multiple annular plate members 24 arranged side by side in the vertical direction. More specifically, they are configured to cover the circumferential gap S between the portions of the multiple annular plate members 24 located on the downstream side in the direction in which the fluid L flows. Here, the portions of the multiple annular plate members 24 located on the downstream side in the direction in which the fluid L flows refer to the portions provided on the downstream side in the fluid flow direction of the suction tank 50. The multiple inflow suppression plates 26 are provided in each of the multiple gaps S partitioned by the multiple annular plate members 24 and the multiple column members 21. In other words, each inflow-restricting plate 26 is positioned between two circumferentially adjacent column members 21 and two vertically adjacent annular plate members 24. Both circumferential ends of the inflow-restricting plate 26 are connected to the two circumferentially adjacent column members 21. A gap S is provided between both circumferential ends of the inflow-restricting plate 26 and the two vertically adjacent annular plate members 24.

[0062] The inflow suppression plate 26 is positioned to cover more than half of the area of ​​the circumferential gap S between the multiple annular plate members 24 arranged in a vertical direction. Preferably, the inflow suppression plate 26 is positioned to cover 70% to less than 100% of the area of ​​the circumferential gap S between the multiple annular plate members 24 arranged in a vertical direction. Multiple inflow suppression plates 26 cover more than 70% of the area of ​​each of the multiple gaps S partitioned by the multiple annular plate members 24 and the multiple column members 21.

[0063] In the second embodiment, the vortex suppression unit 202 reduces the flow that circulates downstream of the pump 200 by covering the gap in the downstream annular plate member 24 with a plurality of inflow suppression plates 26, thereby suppressing air intake vortices generated from the water surface of the downstream suction tank 50 and underwater vortices generated downstream and below. Furthermore, if an air intake vortex occurs, it can be eliminated by contact with the inflow suppression plate 26. In addition, because the inflow suppression plates 26 are provided, air intake vortices from the side can be guided by the inflow flow to the annular plate member 24 in the gap between the inflow suppression plates, thereby eliminating the air intake vortex with the annular plate member 24.

[0064] The other configurations of the second embodiment are the same as those of the first embodiment described above.

[0065] (Effects of the second embodiment)

[0066] In the second embodiment, the same effects can be obtained from the same configuration as in the first embodiment, and the following effects can be obtained from a configuration different from that of the first embodiment.

[0067] In the second embodiment, as described above, an inflow suppression plate 26 is further included, which is positioned downstream of the annular plate member 24 on the side facing the side W of the suction tank 50, so as to cover the gap between the annular plate members 24 in the vertical direction. By covering the gap of the downstream annular plate member 24 with multiple inflow suppression plates 26, the flow that circulates downstream of the pump 200 is reduced, and air intake vortices generated from the water surface downstream of the suction tank 50 and underwater vortices generated downstream and below can be suppressed. Furthermore, if an air intake vortex occurs, it can be eliminated by contact with the inflow suppression plate 26. Moreover, by providing the inflow suppression plate 26, air intake vortices from the side can be guided by the inflow flow to the annular plate member 24 in the gap between the inflow suppression plates, so that the air intake vortex can be eliminated by the annular plate member 24 and the generation of underwater vortices can be suppressed by the rectification of the flow by the annular plate member 24.

[0068] [Third Embodiment] Next, the configuration of the pump 300 according to the third embodiment of the present invention will be described with reference to Figures 11 and 12. Unlike the second embodiment, in the third embodiment, the plurality of annular plate members 24 include vortex suppression wall portions 27 instead of inflow suppression plates.

[0069] As shown in Figures 11 and 12, the vortex suppression wall portion 27 is provided on the uppermost annular plate member 24 among the multiple annular plate members 24. The vortex suppression wall portion 27 is provided along the outer circumference of the uppermost annular plate member 24. The vortex suppression wall portion 27 is configured to project upward at an angle from the outer circumference of the annular plate member 24. The vortex suppression wall portion 27 is provided on at least a portion of the outer circumference of the annular plate member 24 that is located downstream in the direction of fluid flow inside the suction tank 50. Specifically, it is provided in a range of 50% or less of the outer circumference of the annular plate member 24. As a specific example, the vortex suppression wall portion 27 is provided in an angular range of approximately 180 degrees centered on the central member 22 when viewed from above. The direction in which the vortex suppression wall portion 27 inclins is radially away from the suction port. Note that Figures 11 and 12 show an example where there are five annular plate members 24.

[0070] The vortex suppression unit 302 of the third embodiment is equipped with a vortex suppression wall 27, which allows air intake vortices generated from the water surface to come into contact with the vortex suppression wall 27 from below and be eliminated.

[0071] The other configurations of the third embodiment are the same as those of the second embodiment described above.

[0072] (Effects of the third embodiment)

[0073] In the third embodiment, the same effects can be obtained from the same configuration as in the second embodiment, and the following effects can be obtained from different configurations.

[0074] In the third embodiment, as described above, the vortex suppression section 302 has an uppermost annular plate member 24 among the plurality of annular plate members 24 attached to the suction port forming section 10, and has a vortex suppression wall portion 27 provided on at least a part of the outer circumference located downstream in the direction of fluid flow inside the suction water tank 50, which inclins upward from the outer circumference. This makes it possible to eliminate air suction vortices generated from the water surface of the suction water tank 50 downstream by bringing them into contact with the vortex suppression wall portion 27.

[0075] [Fourth Embodiment] Next, with reference to Figure 13, the configuration of the pump 400 according to the fourth embodiment of the present invention will be described. Unlike the first embodiment, in the fourth embodiment, a plate-shaped member 4 is attached to the pump 400.

[0076] The plate-shaped member 4 is configured to extend in the vertical direction. When viewed from above, the plate-shaped member 4 has an L-shape. The plate-shaped member 4 is attached to the outer circumferential surface of the pump 400. The lower end of the plate-shaped member 4 is located above the lower end of the pump casing 1a. The upper end of the plate-shaped member 4 is located below the upper end of the pump 400. Multiple plate-shaped members 4 are attached to the pump 400. At least the lower end of the plate-shaped member 4 needs to be located below the water level of the fluid stored in the suction tank 50. For example, the lower end of the plate-shaped member 4 may be located at the lower end of the pump casing 1a, or near the fastening portion between the pump casing 1a and the suction port forming portion 10.

[0077] In the fourth embodiment, the vortex suppression unit 402 suppresses the generation of vortices and eliminates any generated air intake vortices before they reach the vortex suppression unit 402. Specifically, it destroys the vortex flow before it becomes an air intake vortex to suppress the generation of air intake vortices, and eliminates the air intake vortices by having them come into contact with the plate-shaped member 4.

[0078] The other configurations of the fourth embodiment are the same as those of the first embodiment described above.

[0079] (Effects of the fourth embodiment) In the fourth embodiment, as described above, the same effects can be obtained from the same configuration as in the first embodiment. Furthermore, the following effects can be obtained from a configuration different from that of the first embodiment.

[0080] In the fourth embodiment, as described above, a plate-shaped member 4 is further provided that is attached to the outer circumferential surface and extends in the vertical direction, and the lower end of the plate-shaped member 4 is located above the upper end of the vortex suppression section 402. This allows vortices generated above the vortex suppression section 2 and air intake vortices generated from the water surface to come into contact with the plate-shaped member 4 and be eliminated.

[0081] (modified version) It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims rather than by the description of the embodiments above, and further includes all modifications (exceptions) within the meaning and scope equivalent to the claims.

[0082] For example, in the first to fourth embodiments described above, an example was shown where the pump is a vertical-axis mixed-flow pump, but the present invention is not limited thereto. In the present invention, the pump may be a horizontal-axis pump in which the rotation axis of the impeller extends laterally, or it may be a pump other than a mixed-flow pump, such as a centrifugal pump, a volute pump, or an axial-flow pump.

[0083] Furthermore, while the first to fourth embodiments described above show an example where the pump is a water pump located in a suction tank, the present invention is not limited to this. In the present invention, the pump may be a submersible pump located in water and integrated with a drive unit such as a motor. Alternatively, the pump may be a column pump in which a pipe is located in a suction tank, the pump is housed within the pipe, and the pipe and pump are not fixed together.

[0084] Furthermore, while the first to fourth embodiments described above show examples in which a flow-straightening rib portion is provided on the column member, the present invention is not limited thereto. In the present invention, as shown in the modified example of the vortex suppression portion 602 in Figure 14, the flow-straightening rib portion may not be provided on the column member.

[0085] Furthermore, in the first to fourth embodiments described above, the vertical width of the multiple flow-rectifying partition plates on the column member side was shown to be smaller than the protruding height of the central member in a side view, but the present invention is not limited to this. In the present invention, as shown in the modified example vortex suppression section 702 in Figure 15, the central member does not protrude, and the vertical height of the central member and the vertical height of the flow-rectifying partition plates may be the same.

[0086] Furthermore, although the first to fourth embodiments described above show an example in which eight rectifying partition plates are provided, the present invention is not limited thereto. In the present invention, there may be two or more rectifying partition plates.

[0087] Furthermore, while the first, second, and fourth embodiments described above show an example where there are three annular plate members, and the third embodiment shows an example where there are five annular plate members, the present invention is not limited thereto. In the present invention, the number of annular plate members is not particularly limited as long as there are two or more.

[0088] Furthermore, although the first to fourth embodiments described above show an example in which the annular plate member is circular, the present invention is not limited thereto. In the present invention, the annular plate member may be an annular shape that is elliptical when viewed from above.

[0089] Furthermore, although the first embodiment described above shows an example in which a lid portion is provided on the central member, the present invention is not limited to this. In the present invention, the central member does not need to be provided with a lid portion. Also, in the first embodiment, the central member may be cylindrical in shape.

[0090] Furthermore, although the second to fourth embodiments described above show examples in which the central member is not provided with a lid, the present invention is not limited thereto. In the present invention, the central member may be provided with a lid.

[0091] Furthermore, although the second to fourth embodiments described above show an example in which the central member is cylindrical, the present invention is not limited thereto. In the present invention, the central member may be cylindrical in shape, or it may be polygonal in shape when viewed from above.

[0092] Furthermore, although the fourth embodiment described above shows an example where the plate-like member is L-shaped when viewed from above, the present invention is not limited to this. In the present invention, the plate-like member may be rectangular or arc-shaped when viewed from above. Also, in the fourth embodiment, the suction port forming portion may be provided with reinforcing ribs.

[0093] Furthermore, although the fourth embodiment described above shows an example in which multiple plate-shaped members are attached, the present invention is not limited thereto. In the present invention, only one plate-shaped member may be attached.

[0094] Furthermore, although the second to fourth embodiments described above are each described as pumps with independent configurations, pumps with configurations combining these embodiments may also be used. [Explanation of Symbols]

[0095] 1a Pump casing 2, 202, 302, 402 Vortex suppressor 4 Plate-shaped member 10 Inlet 11 Impeller 21 Column members 22 Central Member 22a Lid 23. Rectifying partition plate 23a Central partition section 23b Column member side partition section 23c Slope section 24 Annular plate member 25. Rib section for rectification 26 Inflow suppression plate 27 Vortex suppression wall 50 Suction tank 100, 200, 300, 400, 500 pumps

Claims

1. A pump placed in a suction tank, A suction port forming section is provided at the lower end, with a suction port that opens downwards, A pump casing in which an impeller is located and connected to the suction port forming section, It comprises a vortex suppression section located below the suction port forming section, The pump includes a plurality of columnar members that extend vertically and are arranged along the lower end of the suction port forming portion, a central member located in the center of the suction port in a top view, and a plurality of flow-rectifying partition plates that are arranged vertically and connect the plurality of columnar members and the central member.

2. The pump according to claim 1, wherein the vortex suppression section is annular in top view and includes a plurality of annular plate members connected to each other by the plurality of column members.

3. The pump according to claim 1, wherein the central member protrudes upward toward the suction port, and the plurality of flow-rectifying partition plates are formed such that the vertical width on the column member side is smaller than the protruding height of the central member.

4. The pump according to claim 3, wherein the plurality of flow-rectifying partition plates, in a side view, have a central partition portion connected to the central member, a column member-side partition portion smaller than the protruding height of the central member and located on the column member side, and an inclined portion that inclines downward toward the column member-side partition portion connecting the central partition portion and the column member-side partition portion.

5. The pump according to claim 1, wherein the plurality of flow-rectifying partition plates are arranged at predetermined angular intervals along the outer circumferential surface of the central member.

6. The pump according to claim 5, wherein the central member has a cylindrical shape.

7. The pump according to claim 6, wherein the central member further comprises a lid portion that closes the opening above the central member.

8. The pump according to claim 7, wherein, in a top view, the diameter of the central member is 10% or more and 50% or less of the impeller inlet diameter.

9. The pump according to claim 1, wherein the vortex suppression portion is provided on the plurality of column members and further includes a plurality of flow-straightening rib portions that protrude from each of the plurality of column members toward the central member and extend in the vertical direction.

10. The pump according to claim 2, wherein the vortex suppression portion further includes an inflow suppression plate positioned downstream of the annular plate member on the side facing the side of the suction tank, so as to cover the gap between the annular plate members in the vertical direction.

11. The pump according to claim 2, wherein the uppermost of the plurality of annular plate members is attached to the suction port forming portion and has a vortex suppression wall portion provided on at least a part of the outer circumference of the annular plate member located on the downstream side when the fluid flows laterally, and which inclins upward from the outer circumference.

12. It further comprises a plate-shaped member attached to the outer surface and extending in the vertical direction, The pump according to claim 1, wherein the lower end of the plate-shaped member is located above the upper end of the vortex suppression portion.

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