JP2015206264A - vertical shaft pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vertical shaft pump capable of restricting not only occurrence of eddy flow just below a bell mouth while reducing both construction period and expenditure but also occurrence of eddy flow caused by striking a circulating flow in an inlet channel against a vortex breaker.SOLUTION: A vertical shaft pump 100 comprises a vortex breaker 20 installed at an upstream side of a bell mouth 4. The vortex breaker 20 comprises baffle side plates 21 having plates in parallel with a central axis CL of the bell mouth 4 and passing through the central axis CL; and vortex breaker structures 25 arranged at the outside ends in a radial direction with the central axis CL of the baffle side plates 21 being applied as a center to restrict occurrence of eddy flow due to striking of flow against the vortex breaker 20 and its peeling state.

Description

  The present invention relates to a vertical shaft pump, and more particularly, to a vertical shaft pump including a vortex preventing device attached to the upstream side of a bell mouth.

  For example, when using a vertical pump installed in the intake channel (hereinafter also simply referred to as “pump”), due to changes in the water level in the intake channel or changes in specifications such as an increase in flow rate (drainage) when the pump is updated, As a result of the change of the flow field in the intake channel, separation of the flow is born, and the suction vortex may be generated starting from the separation point of the flow. If such a vortex is sucked into the pump, it may cause troubles such as excessive vibration and performance degradation, and may cause damage to the pump.

  In order to prevent this vortex generation, for example, the level of the bottom plate of the intake channel is lowered so that the vortex that can be generated near the bottom plate of the intake channel does not easily reach the bell mouth that is the suction pipe. For example, a vortex prevention device having a baffle made of a cross-shaped plate or the like is attached under a bell mouth (see Patent Documents 1 and 2).

JP 2003-328978 A JP 2013-199940 A

  However, the technology for preventing the generation of vortices by lowering the level of the bottom of the intake channel increases the construction period and the construction cost for civil engineering work.

  On the other hand, the technique of preventing the generation of vortex by attaching a vortex preventing device having a baffle formed of a cross-shaped plate or the like under the bell mouth can suppress the swirling flow caused by suction immediately below the bell mouth. Thereby, generation | occurrence | production of the vortex just under bellmouth can be prevented, suppressing the period and expense of construction.

  However, if there is a large swirling flow in the entire intake channel due to the shape of the intake channel, etc., for example, if the specifications are changed when the pump is renewed, the flow field in the intake channel will change, and the intake channel will change. When the flow swirling in the road hits the vortex prevention device and is separated, the vortex prevention device itself may generate a vortex.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is not only the generation of vortices directly under the bell mouth, but also the flow swirling in the intake channel while suppressing the construction period and cost. It is an object of the present invention to provide a vertical shaft pump that can suppress the generation of vortices caused by hitting a vortex preventing device.

  In order to achieve the above-described object, the vertical pump according to the present invention includes a vortex preventing device attached to the upstream side of the bell mouth, and the vortex preventing device is parallel to the central axis of the bell mouth and the center. A first baffle including a plate passing through the shaft, and a vortex generated when the flow hits the vortex preventing device and is separated from a radially outer end centered on the central axis of the first baffle. And a vortex suppressing structure for suppressing.

  The vertical shaft pump according to the present invention includes a vortex preventing device attached to the upstream side of the bell mouth, and the vortex preventing device includes a plate parallel to the central axis of the bell mouth and passing through the central axis. 1 baffle, a plate-like second baffle attached to the opposite side of the first baffle from the bell mouth, and perpendicular to the central axis, and a surface of the second baffle on the bell mouth side. And a columnar structure that suppresses the generation of vortices caused by separation of the flow against the vortex prevention device.

  According to the present invention, while suppressing the construction period and cost, not only the generation of vortex directly under the bell mouth, but also the vertical shaft that can suppress the generation of vortex caused by the flow swirling in the intake channel hitting the vortex prevention device A pump can be provided.

It is a schematic longitudinal cross-sectional view of the vertical shaft pump which concerns on 1st Embodiment of this invention. 2A is an enlarged longitudinal sectional view showing the periphery of the vortex preventing device of the vertical shaft pump according to the first embodiment, and FIG. 2B is a sectional view taken along the line IIb-IIb in FIG. 2 (c) is a schematic perspective view of the vortex prevention device shown in FIG. 2 (a). 3A is an enlarged longitudinal sectional view showing the vicinity of the vortex preventing device of the vertical shaft pump according to the comparative example, FIG. 3B is a sectional view taken along line IIIb-IIIb in FIG. 3A, and FIG. c) is a schematic perspective view of the vortex prevention device shown in FIG. FIG. 4A is an enlarged longitudinal sectional view showing the periphery of the vortex prevention device of the vertical shaft pump according to the second embodiment, and FIG. 4B is a sectional view taken along line IVb-IVb in FIG. 4 (c) is a schematic perspective view of the vortex prevention device shown in FIG. 4 (a). FIG. 5A is an enlarged longitudinal sectional view showing the periphery of the vortex preventing device of the vertical shaft pump according to the third embodiment, and FIG. 5B is a sectional view taken along the line Vb-Vb in FIG. FIG. 5C is a schematic perspective view of the vortex prevention device shown in FIG. FIG. 6A is an enlarged longitudinal sectional view showing the periphery of the vortex preventing device of the vertical shaft pump according to the fourth embodiment, and FIG. 6B is a sectional view taken along line VIb-VIb in FIG. 6 (c) is a schematic perspective view of the vortex prevention device shown in FIG. 6 (a). It is an expanded longitudinal cross-sectional view which shows the vortex prevention device periphery of the vertical shaft pump which concerns on the modification of 4th Embodiment. It is an expanded longitudinal cross-sectional view which shows the vortex prevention apparatus periphery of the vertical shaft pump which concerns on the other modification of 4th Embodiment. FIG. 9A is an enlarged longitudinal sectional view showing the periphery of the vortex preventing device of the vertical shaft pump according to the fifth embodiment, and FIG. 9B is a sectional view taken along line IXb-IXb in FIG. 9 (c) is a schematic perspective view of the vortex prevention device shown in FIG. 9 (a).

Embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
Note that, in the drawings shown below, the same members or corresponding members are denoted by the same reference numerals, and redundant description is omitted as appropriate. In addition, the size and shape of the member may be schematically represented by being modified or exaggerated for convenience of explanation.

[First Embodiment]
First, a first embodiment of the present invention will be described with reference to FIG. 1 and FIG.
FIG. 1 is a schematic longitudinal sectional view of a vertical shaft pump 100 according to the first embodiment of the present invention.
As shown in FIG. 1, the vertical shaft pump 100 is installed in, for example, a water intake channel 1 of a drainage station, and includes a rotary shaft 2 along the vertical direction and an impeller (impeller) 3 attached to the lower end of the rotary shaft 2. A bell mouth (suction pipe) 4 disposed on the upstream side of the impeller 3, a casing liner 40 disposed on the shroud side of the impeller 3, and a casing 41 disposed on the downstream side of the impeller 3. I have. Here, in the vertical shaft pump 100, a mixed flow pump that discharges fluid in an oblique direction with respect to the rotary shaft 2 from the impeller 3 is used.

  The vertical shaft pump 100 is disposed on the downstream side of the impeller 3 and the rotary shaft 2 is inserted therethrough. The vertical shaft 100 is connected to a pumping pipe 5 that allows fluid to flow vertically upward, and to the downstream side of the pumping pipe 5. A discharge bend 6 that changes the flow of fluid sent from the horizontal direction in a horizontal direction, and a prime mover 7 such as a motor connected to the upper end of the rotary shaft 2 that protrudes above the discharge bend 6. A drain pipe 8 is connected to the downstream side of the discharge bend 6. The vertical pump 100 is installed in the intake channel 1 so that the flange 9 provided in the discharge bend 6 is supported by the pump installation floor 11 through the mounting hole 10 from the suction end side. .

  When the impeller 3 is rotated via the rotary shaft 2 by driving the prime mover 7, the water flowing in from the bell mouth 4 is increased in pressure, passes through the casing 41, the pumping pipe 5, the discharge bend 6, and the drain pipe 8. Is discharged to a water discharge channel (not shown). In FIG. 1, reference numeral 12 indicates the bottom plate of the intake channel 1.

  The vertical shaft pump 100 of the present embodiment includes a vortex prevention device 20 that is attached to the lower side (upstream side) of the bell mouth 4.

  2A is an enlarged longitudinal sectional view showing the periphery of the vortex preventing device 20 of the vertical shaft pump 100 according to the first embodiment, and FIG. 2B is a sectional view taken along the line IIb-IIb in FIG. FIG. 2 (c) is a schematic perspective view of the vortex prevention device 20 shown in FIG. 2 (a). Note that the vortex prevention device 20 in FIG. 2A is shown in a side view for easy understanding (the same applies to the following drawings).

  As shown in FIG. 2, the vortex prevention device 20 includes a baffle side plate 21 as a first baffle including a plate parallel to the central axis CL of the bell mouth 4, that is, parallel to the suction direction and passing through the central axis CL. Have. That is, the baffle side plate 21 forms a flat plate including the central axis CL. The central axis CL also serves as the central axis of the vortex prevention device 20. Here, the baffle side plate 21 is configured by a cross-shaped plate centered on the central axis CL.

  However, the baffle side plate 21 is not limited to the above-described configuration, and includes a plurality of (for example, three) plates that extend radially from the central axis CL and are arranged at equal angular intervals in the circumferential direction. It may be.

  Further, the vortex prevention device 20 has a baffle bottom plate 22 as a second baffle attached to the baffle side plate 21 on the opposite side to the bell mouth 4. The baffle bottom plate 22 has a circular plate shape perpendicular to the central axis CL.

  The baffle side plate 21 has a main body portion 211 located on the baffle bottom plate 22 side and a support portion 212 located on the bell mouth 4 side. The support portion 212 extends from the radially outer end centered on the central axis CL in the main body portion 211 toward the bell mouth 4 side. Here, the main body portion 211 and the support portion 212 are integrally formed. The lower end of the main body portion 211 of the baffle side plate 21 is fixed to the baffle bottom plate 22 by welding or the like, and the upper end of the support portion 212 of the baffle side plate 21 is fixed to the ring-shaped connecting ring 23 by welding or the like. .

  Then, the connecting ring 23 is fixed to the lower end portion of the bell mouth 4 by screw fastening or the like, so that the vortex preventing device 20 is attached under the bell mouth 4 (upstream side). However, the connection ring 23 may be omitted, and the upper end of the support portion 212 of the baffle side plate 21 may be directly fixed to the lower end portion of the bell mouth 4 by welding or the like.

  Further, the vortex preventing device 20 is provided at the radially outer end centering on the central axis CL of the baffle side plate 21 and the vortex suppressing structure 25 that suppresses the generation of vortices caused by separation of the flow against the vortex preventing device 20. have.

  In the first embodiment, the vortex suppressing structure 25 is a plate-like rib that is fixed to the radially outer end surface 213 around the central axis CL of the baffle side plate 21, and the flat surface of the rib is the baffle side plate. 21 is fixed to the baffle side plate 21 by welding or the like so as to abut on the end surface 213 of the baffle 21. The height dimension, the width dimension, and the thickness dimension in the direction parallel to the central axis CL of the vortex suppressing structure 25 can be appropriately changed. Moreover, although the vortex suppression structure 25 is comprised so that the baffle bottom plate 22 may be contacted here, it is not limited to this, You may isolate | separate via clearance. The vortex preventing device 20 having the vortex suppressing structure 25 has an outer diameter that is substantially the same as or slightly larger than the outer diameter of the bell mouth 4 and can be inserted through the mounting hole 10 provided in the pump installation floor 11. It is formed in a large size.

Next, the operation of the vertical shaft pump 100 configured as described above will be described.
As shown in FIG. 1, when the water level of the suction target water in the intake channel 1 exceeds the lower end of the bell mouth 4 (see the water level L1 in FIG. 1) and the bell mouth 4 is sufficiently submerged, the vertical shaft pump 100 is When the impeller 3 is started, water is sucked in from the bell mouth 4 by the rotation of the impeller 3, is pressurized, passes through the pumping pipe 5, is discharged to the drain pipe 8 through the discharge bend 6.

  Here, when water is sucked from the bell mouth 4 by the rotation of the impeller 3, if there is no vortex prevention device 20, the swirl flow caused by the sucking directly under the bell mouth 4 is the bottom plate 12 immediately below the bell mouth 4. Can occur on top. However, according to the present embodiment, the swirl flow due to the suction immediately below the bell mouth 4 is suppressed by the baffle side plate 21 formed of the cross-shaped plate of the vortex preventing device 20, and the generation of the vortex just below the bell mouth 4. Can be prevented.

Next, with reference to FIGS. 2 and 3, the operation of the vortex prevention device 20 in the case where there is a flow 13 that largely swirls in the entire intake channel 1 due to the shape of the intake channel 1 and the like will be described.
In such a case, for example, when the specifications of the vertical shaft pump 100 are updated, the flow field in the intake channel 1 changes, and the flow 13 swirling in the intake channel 1 hits the vortex prevention device 20. There is.

  3A is an enlarged longitudinal sectional view showing the periphery of the vortex preventing device 30 of the vertical shaft pump 200 according to the comparative example, and FIG. 3B is a sectional view taken along line IIIb-IIIb in FIG. 3 (c) is a schematic perspective view of the vortex prevention device 30 shown in FIG. 3 (a). The vortex preventing device 30 of the vertical pump 200 according to the comparative example is different from the vortex preventing device 20 of the vertical pump 100 according to the present embodiment in that it does not have the vortex suppressing structure 25 shown in FIG. Since other configurations are the same, description thereof is omitted.

  As shown in FIG. 3B, in the comparative example, the flow 13 swirling in the intake channel 1 hits the end surface 213 of the baffle side plate 21 of the vortex prevention device 30 and peels off, so that the vortex prevention device 30 itself. Vortex 14 is generated.

  On the other hand, as shown in FIG. 2 (b), in the first embodiment, the flow 13 swirling in the intake channel 1 does not hit the end surface 213 of the baffle side plate 21 of the vortex prevention device 20, and the end surface Since the direction of the flow is changed along the surface of the vortex suppressing structure 25 that is a plate-like rib fixed to 213, the generation of vortices can be suppressed.

  Moreover, for example, civil engineering work for preventing the generation of vortices such as lowering the level of the bottom 12 of the intake channel 1 is unnecessary, and the pump can be applied to the bell mouth of an existing pump. It is possible to reduce the construction period and construction cost when remodeling or updating equipment.

  As described above, the vertical shaft pump 100 according to the present embodiment includes the vortex preventing device 20 attached to the upstream side of the bell mouth 4, and the vortex preventing device 20 is parallel to the central axis CL of the bell mouth 4, and A baffle side plate 21 having a plate passing through the central axis CL and a radially outer end centered on the central axis CL of the baffle side plate 21 are provided to suppress the generation of vortices due to the flow hitting the vortex prevention device 20 and peeling. And a vortex suppressing structure 25.

  Therefore, according to the present embodiment, whilst not only the generation of the vortex directly under the bell mouth 4 but also the vortex caused by the flow 13 swirling in the intake channel 1 hitting the vortex prevention device 20 while suppressing the construction period and cost. It is possible to provide the vertical shaft pump 100 that can suppress the occurrence of the above.

[Second Embodiment]
Next, with reference to FIG. 4, the second embodiment of the present invention will be described with a focus on differences from the first embodiment described above, and description of common points will be omitted as appropriate.
FIG. 4A is an enlarged longitudinal sectional view showing the periphery of the vortex preventing device 20a of the vertical shaft pump 100a according to the second embodiment, and FIG. 4B is a sectional view taken along line IVb-IVb in FIG. FIG. 4 (c) is a schematic perspective view of the vortex prevention device 20a shown in FIG. 4 (a).

The second embodiment is different from the first embodiment in that the vortex prevention device 20a has a vortex suppression structure 25a.
In the second embodiment, the vortex suppressing structure 25 a is a columnar body that is fixed to a radially outer end surface 213 centered on the central axis CL of the baffle side plate 21, and the side surface of the columnar body is the end surface of the baffle side plate 21. It is fixed to the baffle side plate 21 by welding or the like so as to come into contact with 213. The height dimension, the diameter dimension, and the thickness dimension in the direction parallel to the center axis CL of the vortex suppressing structure 25a can be changed as appropriate. Moreover, although the vortex suppression structure 25a is comprised so that the baffle bottom plate 22 may be contacted here, it is not limited to this, You may isolate.

  As shown in FIG. 4B, in the second embodiment, the flow 13 swirling in the intake channel 1 is fixed to the end surface 213 without hitting the end surface 213 of the baffle side plate 21 of the vortex preventing device 20a. Since the direction of the flow is changed along the surface of the vortex suppressing structure 25a that is a columnar body, the generation of vortices can be suppressed.

Therefore, according to the second embodiment, the same effects as those of the first embodiment can be obtained.
In addition, although the vortex suppression structure 25a which is a columnar body has a cylindrical shape (cylindrical shape) in FIG. 4, it is not limited thereto, and for example, a triangular prism, a quadrangular column, a cone, a triangular pyramid, and a quadrangular pyramid. It may also be hollow or solid.

[Third Embodiment]
Next, with reference to FIG. 5, the third embodiment of the present invention will be described with a focus on differences from the first embodiment described above, and description of common points will be omitted as appropriate.
FIG. 5A is an enlarged longitudinal sectional view showing the periphery of the vortex preventing device 20b of the vertical shaft pump 100b according to the third embodiment, and FIG. 5B is a sectional view taken along the line Vb-Vb in FIG. FIG. 5 (c) is a schematic perspective view of the vortex prevention device 20b shown in FIG. 5 (a).

The third embodiment is different from the first embodiment in that the vortex prevention device 20b has a vortex suppression structure 25b.
In the third embodiment, the vortex suppressing structure 25 b is a curved curved surface portion formed at the radially outer end centered on the central axis CL of the baffle side plate 21. As shown in FIG. 5B, the bending direction of the curved surface portion needs to be formed along the direction of the flow 13 after investigating the direction of the flow 13 that swirls in the intake channel 1. .

As shown in FIG.5 (b), in 3rd Embodiment, the flow 13 which swirls the inside of the intake channel 1 is the curved surface part formed in the edge part of the radial direction outer side of the baffle side plate 21 of the vortex prevention apparatus 20b. Since it flows along the surface of the vortex suppressing structure 25b and is rectified, the generation of vortices can be suppressed.
Therefore, according to the third embodiment, the same operational effects as those of the first embodiment can be obtained.

[Fourth Embodiment]
Next, with reference to FIG. 6, the fourth embodiment of the present invention will be described with a focus on differences from the first embodiment described above, and description of common points will be omitted as appropriate.
6A is an enlarged longitudinal sectional view showing the periphery of the vortex preventing device 20c of the vertical shaft pump 100c according to the fourth embodiment, and FIG. 6B is a sectional view taken along the line VIb-VIb of FIG. 6A. FIG. 6 (c) is a schematic perspective view of the vortex prevention device 20c shown in FIG. 6 (a).

The fourth embodiment is different from the first embodiment in that the vortex prevention device 20c has a vortex suppression structure 25c.
In the fourth embodiment, the vortex suppressing structure 25 c is a notch formed at the radially outer end centered on the central axis CL of the baffle side plate 21. The size, shape, and number of the vortex suppressing structure 25c can be changed as appropriate.

As shown in FIGS. 6B and 6C, in the fourth embodiment, the flow 13 swirling in the intake channel 1 is the end surface 213 on the radially outer side of the baffle side plate 21 of the vortex preventing device 20c. Since various flows such as a flow that is bent upon hitting and a flow that has passed through the vortex suppression structure 25c that is a notch intersect and cancel each other, the generation of vortices can be suppressed.
Therefore, according to the fourth embodiment, the same operational effects as those of the first embodiment can be obtained.
In addition, although the vortex suppressing structure 25c which is a notch has a circular shape (semi-circular shape) in FIG. 6, it is not limited thereto, and may have an elliptical shape, a quadrangular shape, a triangular shape, or a trapezoidal shape, for example. . Further, the vortex suppressing structure 25c is preferably formed in the vicinity of the baffle bottom plate 22. In this way, vortices that can be generated from the baffle bottom plate 22 can be suppressed.

FIG. 7 is an enlarged vertical cross-sectional view showing the periphery of the vortex preventing device 20d of the vertical shaft pump 100d according to the modification of the fourth embodiment. FIG. 8 is an enlarged longitudinal sectional view showing the periphery of the vortex preventing device 20e of the vertical shaft pump 100e according to another modification of the fourth embodiment.
The vortex suppressing structure 25c of the fourth embodiment shown in FIG. 6 is a notch formed at the radially outer end centering on the central axis CL of the baffle side plate 21, whereas it is shown in FIGS. The vortex suppression structures 25d and 25e according to the modification are through holes.
Such a modification can also provide the same operational effects as the fourth embodiment.
The vortex suppression structure 25d has a circular shape in FIG. 7 and the vortex suppression structure 25e has a trapezoidal shape in FIG. 8, but the shape of the through hole is not limited to these, and may be, for example, an ellipse, a rectangle, or a triangle. May be present.

[Fifth Embodiment]
Next, with reference to FIG. 9, the fifth embodiment of the present invention will be described with a focus on differences from the first embodiment described above, and description of common points will be omitted as appropriate.
9A is an enlarged longitudinal sectional view showing the periphery of the vortex preventing device 20f of the vertical shaft pump 100f according to the fifth embodiment, and FIG. 9B is a sectional view taken along the line IXb-IXb in FIG. 9A. FIG. 9C is a schematic perspective view of the vortex preventing device 20f shown in FIG. 9A.

  The fifth embodiment is different from the first embodiment in that the vortex preventing device 20f has a columnar structure 25f that suppresses the generation of vortices caused by the flow striking the vortex preventing device 20f and separating. The columnar structure 25f is erected on the surface of the baffle bottom plate 22 on the bell mouth 4 side. Here, the columnar structure 25f is close to the end surface 213 of the baffle side plate 21 on the baffle bottom plate 22 and between two adjacent plates of the baffle side plate 21. It is erected near the center of.

  In the fifth embodiment, the columnar structure 25f has the bottom surface of the columnar structure 25f fixed to the surface of the baffle bottom plate 22 by welding or the like. The height dimension, the diameter dimension, and the thickness dimension in the direction parallel to the central axis CL of the columnar structure 25f can be appropriately changed.

  As shown in FIG. 9 (b), in the fifth embodiment, the flow 13 swirling in the intake channel 1 hits the end surface 213 of the baffle side plate 21 of the vortex preventing device 20a to generate vortex, By entering the vicinity of the center on the baffle bottom plate 22, a vortex may be generated. However, since the swirling energy of these vortices is interrupted and lost by the columnar structure 25f, the generation of vortices can be suppressed as a result.

Therefore, according to the fifth embodiment, the same operational effects as those of the first embodiment can be obtained.
Note that the columnar structure 25f has a cylindrical shape in FIG. 9, but is not limited thereto, and may have, for example, a triangular prism, a quadrangular prism, a cone, a triangular pyramid, a quadrangular pyramid, It may be hollow or solid.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to above-described embodiment, Various modifications are included. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. Further, a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  For example, in the first to fourth embodiments, the baffle bottom plate 22 is not always necessary and can be omitted. Further, the vortex suppression structures 25, 25a to 25e and the columnar structure 25f described above can be implemented in appropriate combination.

  In the above-described embodiment, the vertical pump according to the present invention is applied to a mixed flow pump in which the flow discharged from the impeller 3 is in a conical plane with the rotary shaft 2 as an axis. The present invention is not limited, and the present invention can also be applied to an axial flow pump in which the flow discharged from the impeller 3 is in a cylindrical surface concentric with the rotary shaft 2.

4 Bellmouth 20, 20a to 20f Eddy prevention device 21 Baffle side plate (first baffle)
22 Baffle bottom plate (second baffle)
25, 25a-25e Vortex suppression structure 25f Columnar structure 100, 100a-100f Vertical shaft pump 213 End face CL Central axis

Claims (8)

Equipped with a vortex prevention device attached to the upstream side of the bell mouth,
The vortex prevention device is
A first baffle comprising a plate parallel to and passing through the central axis of the bell mouth;
A vortex-suppressing structure that is provided at a radially outer end centered on the central axis of the first baffle, and that suppresses the generation of vortices caused by separation of the flow against the vortex prevention device;
A vertical shaft pump comprising:   The said vortex suppression structure contains the plate-shaped rib which a surface contacts and is fixed to the end surface of the radial direction centering | focusing on the said central axis of the said 1st baffle. Vertical shaft pump.   2. The vertical shaft pump according to claim 1, wherein the vortex suppressing structure includes a columnar body having a side surface in contact with and fixed to a radially outer end surface centering on the central axis of the first baffle. .   2. The vertical shaft pump according to claim 1, wherein the vortex suppressing structure includes a curved surface portion formed at an end portion on a radially outer side centering on the central axis of the first baffle.   5. The vortex suppressing structure includes a notch or a through hole formed at a radially outer end centered on the central axis of the first baffle. The vertical shaft pump according to claim 1. A plate-like second baffle mounted on the opposite side of the first baffle from the bell mouth and perpendicular to the central axis;
A columnar structure that is erected on the surface of the second baffle on the bell mouth side and that suppresses the generation of vortices caused by separation of the flow against the vortex prevention device;
The vertical shaft pump according to any one of claims 1 to 4, wherein the vertical shaft pump is provided. A plate-like second baffle mounted on the opposite side of the first baffle from the bell mouth and perpendicular to the central axis;
A columnar structure that is erected on the surface of the second baffle on the bell mouth side and that suppresses the generation of vortices caused by separation of the flow against the vortex prevention device;
The vertical shaft pump according to claim 5, wherein Equipped with a vortex prevention device attached to the upstream side of the bell mouth,
The vortex prevention device is
A first baffle comprising a plate parallel to and passing through the central axis of the bell mouth;
A plate-like second baffle mounted on the opposite side of the first baffle from the bell mouth and perpendicular to the central axis;
A columnar structure that is erected on the surface of the second baffle on the bell mouth side and that suppresses the generation of vortices caused by separation of the flow against the vortex prevention device;
A vertical shaft pump comprising:

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