JP7730738B2 - Vortex suppression members, pumps and pumping equipment - Google Patents

Description

The present invention relates to a vortex suppression member that suppresses the generation of vortices, a pump equipped with a vortex suppression member, and a pump facility equipped with a pump in a suction tank.

Conventionally, as shown in Figure 27, water 201, such as rainwater, flows into a suction tank 202 at a pumping station, is then pumped up by a vertical pump 203, and sent from the suction tank 202 to a downstream treatment facility. A standard suction tank 202 has a pair of side walls, a rear wall 205, and a bottom 206, and the suction port 208 of the pump 203 is located inside the suction tank 202, in front of the rear wall 205.

When pump 203 is operated, water 201 in suction tank 202 flows into pump 203 from suction port 208 and is sent through pump 203 to a downstream treatment facility. When pump 203 is operating, a submerged vortex 211 and an air-suction vortex 212 may occur within suction tank 202.

The underwater vortex 211 is a vortex that occurs when the pressure of a vortex generated from the bottom surface 206 or side wall surface of the suction tank 202 drops below the steam pressure and is sucked into the suction port 208. The air-sucking vortex 212 is a vortex that occurs from the water surface toward the suction port 208, entraining air above the water surface and sucking it into the suction port 208.

If such underwater vortices 211 or air-suction vortices 212 are sucked into the pump 203 through the suction port 208, there is a risk of severe vibrations and loud noises occurring while the pump 203 is operating.

In order to suppress the occurrence of the underwater vortex 211 and air-suction vortex 212 described above, a common technique is to install a vortex prevention plate (not shown) on the rear wall surface 205 or bottom surface 206 of the suction sump 202. However, in addition to this technique, a vortex suppression member 220 may also be attached to the bell mouth 221 of the vertical pump 203, as shown in Figures 28 and 29.

The vortex suppression member 220 has a mounting flange 222 joined to the lower end of the bell mouth 221, an arc-shaped curved arc wall 223 extending downward from the mounting flange 222, and a flat baffle plate 224 provided between both circumferential ends of the arc wall 223. The arc wall 223 and the baffle plate 224 form a cylindrical body 225 that is open in both the upward and downward directions.

As a result, when the pump 203 is operating, the arcuate wall 223 of the vortex suppression member 220 passes beside the pump 203 from the upstream side near the water surface, descends from behind the pump 203 along the rear wall surface 205 of the suction tank 202, and then provides resistance to the flows F1 and F1' that are sucked into the suction port 208.

As a result, the velocity V1 of the flow F1 of the water 201 near the water surface slows, and the velocity of the downward flow F1' descending from behind the casing 226 along the rear wall surface 205 decreases, reducing the vorticity near the suction port 208 and suppressing the generation of underwater vortices.

Furthermore, flow F2 near the bottom surface 206 of the suction tank 202 approaches the pump 203 from the upstream side 214 and flows into the suction port 208. At this time, the water 201 just before flowing into the suction port 208 collides with the baffle plate 224, preventing the generation of a swirling flow and effectively suppressing the generation of underwater vortices.

In addition, as described above, the arcuate wall 223 of the vortex suppression member 220 acts as a resistance to the downward flow F1' that descends from behind the casing 226 along the rear wall surface 205, increasing the flow F3 that descends from near the water surface on the upstream side 214 of the casing 226 and is sucked into the suction port 208. This weakens the downward flow F1' that descends from behind the casing 226 along the rear wall surface 205, thereby suppressing the occurrence of air-sucking vortices. This prevents the pump 1 from generating severe vibrations and loud noises during operation.

The above-described vortex suppression member 220 is described, for example, in Patent Document 1 below.

Patent Publication No. 2019-157808

However, in the above-mentioned conventional type, the flow rate of the vertical pump 203 during operation is set to a predetermined flow rate. However, if the flow rate is increased beyond the predetermined flow rate and the vertical pump 203 is operated without changing its diameter, it becomes difficult to sufficiently suppress the occurrence of underwater vortices or air suction vortices, and there is a risk that underwater vortices or air suction vortices will occur.

The present invention aims to provide a vortex suppression member, pump, and pump equipment that can sufficiently suppress the occurrence of underwater vortices and air-sucking vortices.

In order to achieve the above object, the first invention provides a vortex suppression member that can be attached to a bell mouth of a pump, comprising:
an arc wall curved in an arc shape extending downward from a part of the peripheral edge of the suction port of the bell mouth;
a first partition wall and a second partition wall provided on the arc wall;
The first and second partition walls are arranged in parallel,
a cylindrical body is formed that is surrounded by the arc wall and the first partition wall and is open both in the upper and lower directions;
the upper ends of the first and second partition walls are lower than the upper end of the arc wall;
a bottom plate facing downward from the suction port is attached between the first partition wall and the second partition wall;
a bottom opening is formed between the arc wall and the bottom plate and between the first partition wall and the second partition wall;
A flow passage is formed through which the fluid flows from the bottom of the cylinder through the bottom opening into the cylinder and exits to the top of the cylinder .

According to this design, the vortex suppression member is attached to the bell mouth, and the pump is operated with the arc-shaped wall of the vortex suppression member facing the rear wall of the suction sump. This causes the arc-shaped wall to provide resistance to the flow (flow near the water surface) that passes beside the pump from the upstream side in front of the pump, descends along the rear wall from behind the pump, and is then sucked into the suction port. As a result, the amount of water sucked into the suction port from the rear wall of the suction sump is less than the amount of water sucked into the suction port from the upstream side in front of the sump. Because the arc-shaped wall provides resistance to the flow descending along the rear wall from behind the pump, the flow descending from near the water surface on the upstream side in front of the pump and sucked into the suction port increases, while the flow descending along the rear wall from behind the pump is weakened, thereby suppressing the generation of air-sucking vortices.

Furthermore, because the upper end of the partition wall is lower than the upper end of the arc wall, the flow rate from the upstream side in front of the pump, passing above the partition wall and flowing into the inside of the cylinder, increases, further weakening the flow that flows downward from behind the pump along the rear wall of the suction sump, thereby sufficiently suppressing the occurrence of air-sucking vortices.

In addition, the flow near the bottom of the suction tank approaches the pump from the upstream side and hits the partition wall, preventing the generation of swirling flow and suppressing the generation of underwater vortices.

The second invention is a vortex suppression member that can be attached to a bell mouth of a pump,
an arc wall curved in an arc shape extending downward from a part of the peripheral edge of the suction port of the bell mouth;
a first partition wall and a second partition wall provided on the arc wall;
The first and second partition walls are arranged in parallel,
a cylindrical body is formed that is surrounded by the arc wall and the first partition wall and is open both in the upper and lower directions;
the lower ends of the first and second partition walls are located above the lower end of the arc wall;
a bottom plate facing downward from the suction port is attached between the first partition wall and the second partition wall;
a bottom opening is formed between the arc wall and the bottom plate and between the first partition wall and the second partition wall;
A flow passage is formed through which the fluid flows from the bottom of the cylinder through the bottom opening into the cylinder and exits to the top of the cylinder .

As a result, because the lower end of the partition wall is higher than the lower end of the arc wall, the flow rate from the upstream side of the pump, passing below the partition wall and flowing into the inside of the cylinder, increases, further weakening the flow that flows downward from behind the pump along the rear wall of the suction tank, thereby sufficiently suppressing the occurrence of air-sucking vortices.

In addition, the flow near the bottom of the suction tank approaches the pump from the upstream side and hits the partition wall, preventing the generation of swirling flow and suppressing the generation of underwater vortices.

The third invention is a vortex suppression member that can be attached to a bell mouth of a pump,
an arc wall curved in an arc shape extending downward from a part of the peripheral edge of the suction port of the bell mouth;
a first partition wall and a second partition wall provided on the arc wall;
The first and second partition walls are arranged in parallel,
a cylindrical body is formed that is surrounded by the arc wall and the first partition wall and is open both in the upper and lower directions;
An opening or a notch that is open to both the inside and outside of the cylindrical body is formed in the first partition wall ,
a bottom plate facing downward from the suction port is attached between the first partition wall and the second partition wall;
a bottom opening is formed between the arc wall and the bottom plate and between the first partition wall and the second partition wall;
A flow passage is formed through which the fluid flows from the bottom of the cylinder through the bottom opening into the cylinder and exits to the top of the cylinder .

As a result, openings or cutouts that open to both the inside and outside of the cylinder are formed in the partition wall, increasing the flow rate from the upstream side in front of the pump through the openings or cutouts in the partition wall into the inside of the cylinder. This further weakens the flow that flows downward along the rear wall of the suction tank from behind the pump, thereby sufficiently suppressing the occurrence of air-sucking vortices.

In addition, the flow near the bottom of the suction tank approaches the pump from the upstream side and hits the partition wall, preventing the generation of swirling flow and suppressing the generation of underwater vortices.

In the vortex suppression member according to the fourth aspect of the present invention, the bottom plate is disposed on an extension of the axis of the bell mouth.

Accordingly, underwater vortices tend to occur near the extension of the bell mouth's axis, so by positioning the bottom plate on the extension of the bell mouth's axis, the occurrence of underwater vortices can be sufficiently suppressed.

The vortex suppression member in this fifth invention has a lower protruding member that protrudes inward toward the inside of the cylindrical body at the lower end of the arc wall.

As a result, the distance that some of the water in the suction tank travels from the water surface down along the rear wall behind the pump, then passes through the inside of the cylindrical body of the vortex suppression member before being sucked into the suction port is longer by a distance equivalent to the protrusion width of the lower protrusion member, compared to when the lower protrusion member is not provided. This increases the resistance to water flowing from the rear wall of the suction tank through the inside of the cylindrical body of the vortex suppression member to the suction port, further reducing the flow rate sucked into the suction port from the rear wall side and further weakening the flow descending along the rear wall from behind the pump, thereby sufficiently suppressing the occurrence of air-sucking vortices.

A sixth aspect of the present invention is a pump including the vortex suppression member according to any one of the first to fifth aspects,
The vortex suppressor is attached to the bell mouth.

The present invention provides a pump system including the pump according to the sixth invention in a water suction tank,
The suction port of the bell mouth is provided in the suction tank and is located on the front side of the rear wall of the suction tank.
The arcuate wall of the vortex suppressing member faces the rear wall surface of the suction sump.

As described above, the present invention can sufficiently suppress the occurrence of underwater vortices and air-sucking vortices.

1 is a side view of a pump according to a first embodiment of the present invention; 2 is a view taken along the line XX in FIG. 1. FIG. 2 is an enlarged cross-sectional view of a joint between a bell mouth and a vortex suppression member of the pump according to the first embodiment. FIG. 2 is a view of the pump's vortex suppression member as viewed obliquely from above. FIG. 2 is a view of the pump's vortex suppression member as viewed obliquely from below. FIG. 2 is a plan view of the vortex suppression member of the pump according to the first embodiment. 7 is a view taken along the line XX in FIG. 6. FIG. 2 is a bottom view of the vortex suppression member of the pump according to the first embodiment. 8 is a view taken along the line XX in FIG. 7. 10A and 10B are diagrams showing the water flow and approach velocity distribution in the suction sump when the pump is operating. FIG. 10 is a diagram of a vortex suppression member of a pump according to a second embodiment of the present invention, viewed obliquely from below. FIG. 2 is a cross-sectional view of a vortex suppression member of the pump according to the first embodiment. FIG. 11 is a diagram showing a vortex suppression member of a pump according to a third embodiment of the present invention, viewed obliquely from above. FIG. 2 is a view of the pump's vortex suppression member as viewed obliquely from below. FIG. 2 is a cross-sectional view of a vortex suppression member of the pump according to the first embodiment. FIG. 10 is a diagram showing a vortex suppression member of a pump according to a fourth embodiment of the present invention, viewed obliquely from above. FIG. 2 is a view of the pump's vortex suppression member as viewed obliquely from below. FIG. 2 is a cross-sectional view of a vortex suppression member of the pump according to the first embodiment. FIG. 13 is a diagram showing a vortex suppression member of a pump according to a fifth embodiment of the present invention, viewed obliquely from above. FIG. 2 is a view of the pump's vortex suppression member as viewed obliquely from below. FIG. 2 is a plan view of the vortex suppression member of the pump according to the first embodiment. 22 is a view taken along the arrows XX in FIG. 21. FIG. 2 is a bottom view of the vortex suppression member of the pump according to the first embodiment. FIG. 13 is a diagram showing a vortex suppression member of a pump according to a sixth embodiment of the present invention, viewed obliquely from below. FIG. 2 is a cross-sectional view of a vortex suppression member of the pump according to the first embodiment. FIG. 13 is a diagram showing a vortex suppression member of a pump according to a seventh embodiment of the present invention, viewed obliquely from below. FIG. 1 is a schematic diagram of a conventional pump and suction tank. FIG. 10 is a diagram showing the water flow and approach velocity distribution in the suction sump when a pump equipped with a conventional vortex suppressor is operating. FIG. 10 is a diagram of a conventional vortex suppression member viewed obliquely from below.

Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
In the first embodiment, as shown in FIGS. 1 and 2 , reference numeral 1 denotes a pump facility installed at a pumping station, and the pump facility 1 includes a suction tank 2 and a pump 10 that sucks up water 3, such as rainwater, that has flowed into the suction tank 2 and sends it to a downstream treatment facility.

The suction tank 2 is a standard flow rate open type, and has a pair of left and right side walls 5, a rear wall 7, and a bottom 8. Water 3 flows in from the upstream side 9, just before the pump 10.

The pump 10 is a vertical shaft pump and includes a pump body 11 and a vortex suppression member 12. The pump body 11 includes a casing 14 extending vertically, a rotatable main shaft 15 inserted into the casing 14, an impeller 16 that rotates together with the main shaft 15, and a rotary drive device 17 that rotates the main shaft 15.

The casing 14 has a straight lift pipe 19, a pump case 20 connected to the lower end of the lift pipe 19, a bell mouth 21 connected to the lower end of the pump case 20, and a discharge elbow 22 connected to the upper end of the lift pipe 19. As shown in Figures 1 and 3, the bell mouth 21 has a suction port 23 and a flange 24 at its lower end. The suction port 23 is located inside the suction tank 2, on the near side (upstream side) of the rear wall surface 7.

As shown in Figures 4 to 9, the vortex suppression member 12 is detachably attached to the lower end of the bellmouth 21 and includes an arc-shaped curved arc wall 30 extending downward from part of the periphery of the suction port 23 of the bellmouth 21, an annular mounting flange 31 (an example of a mounting member) attached to the upper end of the arc wall 30, two (or more) partition walls 32, 33 that separate the inside of the arc wall 30, a bottom plate 34 supported by the arc wall 30 via the partition walls 32, 33, and a lower overhang member 41 attached to the lower end of the arc wall 30.

As shown in Figures 1 and 2, the arc wall 30 faces the rear wall surface 7 of the suction tank 2. Also, as shown in Figure 3, the mounting flange 31 is detachably joined to the flange 24 of the bell mouth 21 by a plurality of bolts 36.

The partition walls 32, 33 are flat, parallel plates, and the first partition wall 32 is located between both ends of the arc wall 30 in the circumferential direction 37. This forms a cylindrical body 38 that is surrounded by the arc wall 30 and the first partition wall 32 and is open both above and below. The second partition wall 33 is located inside the cylindrical body 38 and attached to the arc wall 30.

As shown in Figure 7, the heights of the first and second partition walls 32, 33 are set so that the upper ends 32a, 33a of the first and second partition walls 32, 33 are lower than the upper end 30a of the arc wall 30, and the lower ends 32b, 33b of the first and second partition walls 32, 33 are at the same height as the lower end 30b of the arc wall 30.

The bottom plate 34 is a rectangular flat plate attached between the lower ends 32b, 33b of the first and second partition walls 32, 33, facing downward from the suction port 23 of the bell mouth 21 and positioned on an extension of the axis 40 of the bell mouth 21.

The lower protruding member 41 protrudes radially inward from the arc wall 30 (i.e., toward the inside of the cylindrical body 38) and is C-shaped when viewed from the axial direction (vertical direction) of the bell mouth 21.

When viewed from the axial direction of the bell mouth 21, the bottom plate 34 is located inside the contour of the suction port 23 of the bell mouth 21. Flow passages 42a, 42b, and 42c are formed that run from below the arc wall 30, passing between the arc wall 30 and the bottom plate 34, and out to above the arc wall 30.

The operation of the above configuration is explained below.

When the pump 10 is operated, the impeller 16 (see Figure 1) rotates, and water 3 in the suction tank 2 is sucked into the casing 14 through the suction port 23 of the bellmouth 21 and sent to the downstream treatment facility through the discharge elbow 22. As shown in Figure 10, the arcuate wall 30 of the vortex suppression member 12 acts as a resistance to the flows F1 and F1', slowing the velocity V1 of the flow F1 of water 3 near the water surface and reducing the velocity of the downward flow F1' descending from behind the casing 14 along the rear wall surface 7. This reduces the vorticity near the suction port 23 and suppresses the generation of underwater vortices.

Furthermore, the flow F2 near the bottom surface 8 of the suction tank 2 approaches the pump 10 from the upstream side 9 and flows into the suction port 23. However, just before flowing into the suction port 23, the water 3 collides with at least one of the first and second partition walls 32, 33, preventing the generation of a swirling flow and more effectively suppressing the generation of underwater vortices.

Furthermore, since underwater vortices tend to occur near the extension of the axis 40 of the bell mouth 21, the generation of underwater vortices can be sufficiently suppressed by positioning the bottom plate 34 on the extension of the axis 40 of the bell mouth 21.

Furthermore, as described above, the arcuate wall 30 of the vortex suppression member 12 acts as a resistance to the downward flow F1', increasing the flow F3 that descends from near the water surface on the upstream side 9 of the casing 14 and is sucked into the suction port 23, as shown in Figure 10. This weakens the downward flow F1' that descends along the rear wall surface 7 from behind the casing 14, thereby suppressing the generation of air-sucking vortices.

Furthermore, a portion of the water 3 in the suction sump 2 flows downward from the water surface along the rear wall 7 behind the pump 10, and then, as shown in Figures 4 and 5, passes through the inside of the cylindrical body 38 of the vortex suppression member 12 (i.e., through the flow passages 42a, 42b, and 42c) and is sucked into the suction port 23 of the bellmouth 21. At this time, as shown in Figure 7, the distance the water flows through the flow passage 42a and into the suction port 23 is longer by a distance equivalent to the overhang width W of the lower overhang member 41 in the radial direction of the arcuate wall 30 than when the lower overhang member 41 is not provided (see Figure 12 of the second embodiment, described below). This increases the resistance of the water 3 as it flows from the rear wall 7 through the inside of the cylindrical body 38 and into the suction port 23, further reducing the flow rate sucked into the suction port 23 from the rear wall 7. This further weakens the downward flow F1' that flows downward along the rear wall 7 from behind the pump 10, further suppressing the occurrence of air-intake vortices.

Furthermore, as shown in FIG. 7, the upper ends 32a, 33a of the first and second partition walls 32, 33 of the vortex suppression member 12 are located lower than the upper end 30a of the arc wall 30. This increases the flow rate from the upstream side 9 in front of the pump 10, passing above the first or second partition wall 32, 33 and flowing into the inside of the tubular body 38. This further weakens the downward flow F1' that descends from behind the pump 10 along the rear wall surface 7 of the suction sump 2. This sufficiently suppresses the occurrence of air-suction vortices.

In addition, when some of the water 3 in the suction tank 2 flows from below the arc-shaped wall 30 of the vortex suppression member 12 through the flow passages 42a, 42b, and 42c into the suction port 23 of the pump 10, it passes from bottom to top between the arc-shaped wall 30 and the bottom plate 34. This prevents the bottom of the suction port 23 of the pump 10 from being covered too much by the bottom plate 34 of the vortex suppression member 12, which would result in excessive pressure loss (i.e., reduced pump efficiency), or prevents the local flow velocity on the upstream side 9 in front of the vortex suppression member 12 from increasing too much, causing vortices to be generated in other locations.

As a result, even when the pump 10 is operated at a flow rate greater than the specified flow rate without changing its diameter, the occurrence of underwater vortices and air-suction vortices can be sufficiently suppressed, preventing the pump 10 from generating severe vibrations or loud noises during operation.

Second Embodiment
In the first embodiment described above, as shown in FIG. 7, a lower protruding member 41 is provided at the lower end of the arc wall 30, but in the second embodiment, as shown in FIGS. 11 and 12, a lower protruding member 41 is not provided.

This provides the same effects and benefits as the first embodiment described above.

(Third embodiment)
In the first embodiment described above, the bottom plate 34 and the lower overhanging member 41 are separate as shown in Figures 7 and 8, but in the third embodiment, the bottom plate 34 and the lower overhanging member 41 are connected together as a single unit as shown in Figures 13 to 15. The lower overhanging member 41 is formed in a fan shape when viewed from the axial direction (vertical direction) of the bell mouth 21. The fan-shaped area surrounded by the lower end of the arc wall 30 and the lower end of the second partition wall 33 is closed off by the lower overhanging member 41.

In addition, the upper ends 32a, 33a of the first and second partition walls 32, 33 are each lower than the upper end 30a of the arc wall 30, and the lower ends 32b, 33b of the first and second partition walls 32, 33 are each at the same height as the lower end 30b of the arc wall 30.

Flow passages 42b and 42c are formed that run from below the arc wall 30 through the gap between the arc wall 30 and the bottom plate 34 and out to above the arc wall 30.

As a result, because the flow passage 42a shown in Figure 4 of the first embodiment is closed by the lower overhanging member 41, some of the water 3 in the suction sump 2 flows downward from the water surface along the rear wall surface 7 behind the pump 10, and then passes through flow passages 42b and 42c as shown in Figures 13 to 15, rather than through the flow passage 42a of the vortex suppression member 12, before being sucked into the suction port 23 of the bellmouth 21. Therefore, the distance traveled by the flow passing through the inside of the cylindrical body 38 before being sucked into the suction port 23 is longer by a distance equivalent to the overhang width W of the lower overhanging member 41 in the front-to-rear direction, compared to when the lower overhanging member 41 is not provided (see Figure 12 of the second embodiment described above).

This increases the resistance when the water 3 flows from the rear wall surface 7 through the inside of the cylindrical body 38 into the suction port 23, further reducing the flow rate sucked into the suction port 23 from the rear wall surface 7. This further weakens the downward flow F1' that flows from behind the pump 10 down along the rear wall surface 7, further suppressing the occurrence of an air-sucking vortex.

Furthermore, as with the first embodiment described above, the generation of underwater vortices is further suppressed.

(Fourth embodiment)
16 to 18, in the fourth embodiment, the lower ends 32b and 33b of the first and second partition walls 32 and 33 are respectively located higher than the lower end 30b of the arc wall 30. Furthermore, the upper ends 32a and 33a of the first and second partition walls 32 and 33 are respectively located at approximately the same height as the upper end 30a of the arc wall 30.

Flow passages 42a, 42b, and 42c are formed that run from below the arc wall 30 through the gap between the arc wall 30 and the bottom plate 34 to above the arc wall 30. The bottom plate 34 is also located higher than the lower protruding member 41.

As a result, because the lower ends 32b, 33b of the first and second partition walls 32, 33 are located higher than the lower end 30b of the arc wall 30, the flow rate flowing from the upstream side 9 in front of the pump 10, passing below the first or second partition wall 32, 33 and into the inside of the tubular body 38, increases, and the downward flow F1' that flows from behind the pump 10 and along the rear wall surface 7 of the suction tank 2 is further weakened accordingly. This sufficiently suppresses the occurrence of air-suction vortices.

Furthermore, a portion of the water 3 in the suction sump 2 flows downward from the water surface along the rear wall 7 behind the pump 10, then passes through the flow passages 42a, 42b, and 42c of the vortex suppression member 12 and is sucked into the suction port 23 of the bellmouth 21. As shown in FIG. 18, the distance traveled by the water 3 through the flow passage 42a before being sucked into the suction port 23 is longer by a distance equivalent to the extension width W of the lower extension member 41 in the front-to-rear direction than when the lower extension member 41 is not provided (see FIG. 12 of the second embodiment described above). This increases the resistance of the water 3 as it flows from the rear wall 7 through the inside of the cylindrical body 38 and into the suction port 23, further reducing the flow rate sucked into the suction port 23 from the rear wall 7. This further weakens the downward flow F1' that flows downward along the rear wall 7 from behind the pump 10, further suppressing the occurrence of air-sucking vortices.

Fifth Embodiment
19 to 23, in the fifth embodiment, one (single) partition wall 60 is provided on the arc wall 30 to separate the inside of the arc wall 30. This forms a cylinder 38 that is surrounded by the arc wall 30 and the partition wall 60 and is open both above and below.

The bottom plate 34 is a roughly rectangular flat plate, with both short edges 34a of the bottom plate 34 attached to the inside of the arc wall 30, and one long edge 34b of the bottom plate 34 attached to the lower end 60b of the partition wall 60.

The bottom plate 34 is located at a higher position than the lower protruding member 41. Furthermore, the upper end 60a of the partition wall 60 is at approximately the same height as the upper end 30a of the arc wall 30. Furthermore, the lower end 60b of the partition wall 60 is located higher than the lower end 30b of the arc wall 30.

A flow passage 42 is formed that runs from below the arc wall 30, passing between the arc wall 30 and the bottom plate 34, and out to above the arc wall 30.

As a result, because the lower end 60b of the partition wall 60 is positioned higher than the lower end 30b of the arc wall 30, the flow rate flowing from the upstream side 9 of the suction tank 2, below the bottom plate 34 and below the partition wall 60, into the inside of the cylindrical body 38 increases, further weakening the downward flow F1' that flows from behind the pump 10 along the rear wall surface 7 of the suction tank 2. This sufficiently suppresses the occurrence of air-suction vortices.

Furthermore, as shown in Figure 22, after a portion of the water 3 in the suction sump 2 descends from the water surface along the rear wall surface 7 behind the pump 10, the distance it travels through the flow passage 42 of the vortex suppression member 12 before being sucked into the suction port 23 of the bellmouth 21 is longer by a distance equivalent to the protrusion width W of the lower protrusion member 41 in the front-to-rear direction compared to when the lower protrusion member 41 is not provided (see Figure 12 of the second embodiment described above). This increases the resistance when the water 3 flows from the rear wall surface 7 side through the inside of the cylindrical body 38 into the suction port 23, further reducing the flow rate sucked into the suction port 23 from the rear wall surface 7 side, and further weakening the downward flow F1' descending along the rear wall surface 7 from behind the pump 10, further suppressing the occurrence of air-sucking vortices.

(Sixth embodiment)
24 and 25 , in the sixth embodiment, the upper ends 32a, 33a of the first and second partition walls 32, 33 are each substantially flush with the upper end 30a of the arc-shaped wall 30, and the lower ends 32b, 33b of the first and second partition walls 32, 33 are each flush with the lower end 30b of the arc-shaped wall 30. In addition, the first and second partition walls 32, 33 are each formed with an opening 61 that opens to both the inside and outside of the cylindrical body 38.

This increases the flow rate flowing from the upstream side 9 of the pump 10 through the openings 61 in the first and second partition walls 32, 33 into the inside of the cylindrical body 38, further weakening the downward flow F1' that flows from behind the pump 10 along the rear wall surface 7 of the suction tank 2. This effectively suppresses the occurrence of air-sucking vortices.

In the sixth embodiment described above, openings 61 are formed in the first and second partition walls 32, 33, respectively, but they may also be formed in only the first partition wall 32.

Seventh Embodiment
In the sixth embodiment described above, as shown in FIG. 24, openings 61 are formed in the first and second partition walls 32, 33. However, in the seventh embodiment, instead of the openings 61, notches 62 are formed in the first and second partition walls 32, 33 as shown in FIG. 26.

This increases the flow rate from the upstream side 9 of the suction tank 2 through the notches 62 in the first and second partition walls 32, 33 into the inside of the cylindrical body 38, further weakening the downward flow F1' that descends from behind the pump 10 along the rear wall surface 7 of the suction tank 2. This effectively suppresses the occurrence of air-sucking vortices.

In the seventh embodiment described above, the notch 62 is formed in each of the first and second partition walls 32, 33, but it may also be formed only in the first partition wall 32.

In each of the above embodiments, as shown in FIG. 3, the vortex suppression member 12 is detachably attached to the lower end of the bellmouth 21 using bolts 36. However, the vortex suppression member 12 may also be integrally attached to the lower end of the bellmouth 21 by welding or the like. In this case, the mounting flange 31 may not be provided on the arc wall 30 of the vortex suppression member 12, and the upper end of the arc wall 30 of the vortex suppression member 12 may be welded to the lower end of the bellmouth 21.

In each of the above embodiments, the bottom plate 34 is rectangular, but the shape of the bottom plate 34 may also be circular, oval, or any other polygonal shape other than a square.

In each of the above embodiments, the bottom plate 34 is located at the same position as or above the lower end 30b of the arc wall 30, but it may also be located below the lower end 30b.

In each of the above embodiments, the partition walls 32, 33, and 60 are in a vertical position when the vortex suppression member 12 is attached to the pump 10, but the partition walls 32, 33, and 60 may be inclined in whole or in part so as to guide the flow from the upstream side 9 of the suction tank 2 to the suction port 23 of the pump 10.

In the above embodiments, the partition walls 32, 33, and 60 are flat, but they may have curved or bent portions in whole or in part.

DESCRIPTION OF SYMBOLS 1 Pump equipment 2 Suction tank 7 Rear wall surface 10 Pump 12 Vortex suppression member 21 Bell mouth 23 Suction port 30 Arc wall 30a Upper end portion of arc wall 30b Lower end portion of arc wall 32, 33 Partition wall 32a, 33a Upper end portion of partition wall 32b, 33b Lower end portion of partition wall 34 Bottom plate 38 Cylinder 40 Axis center 41 Lower protruding member 60 Partition wall 60a Upper end portion of partition wall 60b Lower end portion of partition wall 61 Opening 52 Notch

Claims (7)

A vortex suppression member attachable to a bell mouth of a pump, comprising:
an arc wall curved in an arc shape extending downward from a part of the peripheral edge of the suction port of the bell mouth;
a first partition wall and a second partition wall provided on the arc wall;
The first and second partition walls are arranged in parallel,
a cylindrical body is formed that is surrounded by the arc wall and the first partition wall and is open both in the upper and lower directions;
the upper ends of the first and second partition walls are lower than the upper end of the arc wall;
a bottom plate facing downward from the suction port is attached between the first partition wall and the second partition wall;
a bottom opening is formed between the arc wall and the bottom plate and between the first partition wall and the second partition wall;
A vortex suppression member characterized in that a flow passage is formed through which air flows into the cylinder from below through a bottom opening and exits above the cylinder . A vortex suppression member attachable to a bell mouth of a pump, comprising:
an arc wall curved in an arc shape extending downward from a part of the peripheral edge of the suction port of the bell mouth;
a first partition wall and a second partition wall provided on the arc wall;
The first and second partition walls are arranged in parallel,
a cylindrical body is formed that is surrounded by the arc wall and the first partition wall and is open both in the upper and lower directions;
the lower ends of the first and second partition walls are located above the lower end of the arc wall;
a bottom plate facing downward from the suction port is attached between the first partition wall and the second partition wall;
a bottom opening is formed between the arc wall and the bottom plate and between the first partition wall and the second partition wall;
A vortex suppression member characterized in that a flow passage is formed through which air flows into the cylinder from below through a bottom opening and exits above the cylinder . A vortex suppression member attachable to a bell mouth of a pump, comprising:
an arc wall curved in an arc shape extending downward from a part of the peripheral edge of the suction port of the bell mouth;
a first partition wall and a second partition wall provided on the arc wall;
The first and second partition walls are arranged in parallel,
a cylindrical body is formed that is surrounded by the arc wall and the first partition wall and is open both in the upper and lower directions;
An opening or a notch that is open to both the inside and outside of the cylindrical body is formed in the first partition wall ,
a bottom plate facing downward from the suction port is attached between the first partition wall and the second partition wall;
a bottom opening is formed between the arc wall and the bottom plate and between the first partition wall and the second partition wall;
A vortex suppression member characterized in that a flow passage is formed through which air flows into the cylinder from below through a bottom opening and exits above the cylinder . 4. The vortex suppression member according to claim 1, wherein the bottom plate is disposed on an extension of the axis of the bell mouth. A vortex suppression member according to any one of claims 1 to 4, characterized in that a lower protruding member that protrudes inward toward the cylindrical body is provided at the lower end of the arc wall. A pump equipped with the vortex suppression member according to any one of claims 1 to 5,
A pump characterized in that a vortex suppressing member is attached to a bell mouth. A pump facility provided with the pump according to claim 6 in a water suction tank,
The suction port of the bell mouth is provided in the suction tank and is located on the front side of the rear wall of the suction tank.
A pump facility characterized in that the arc-shaped wall of the vortex suppressing member faces a rear wall surface of the suction tank.