JP2023083627A - Vortex suppression member, pump and pumping equipment - Google Patents

Abstract

To provide a vortex suppression member capable of sufficiently suppressing the occurrence of underwater vortexes or air suction vortexes.SOLUTION: A vortex suppression member 12 which can be mounted to a bell mouth of a pump includes a circular-arc wall 30 extending from a part of the peripheral edge of a suction port of the bell mouth to the lower side while being curved in a circular-arc shape, and a bottom plate 34 supported by the circular-arc wall 30 and opposed to the lower side of the suction port, wherein the bottom plate 34 is arranged on the extension of an axial center 40 of the bell mouth and formed with a distribution path 42a passing through the lower side of the circular-arc wall 30 to the upper side of the circular-arc wall 30 while running between the circular-arc wall 30 and the bottom plate 34.SELECTED DRAWING: Figure 7

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vortex suppressing member that suppresses the generation of vortices, a pump provided with the vortex suppressing member, and a pump facility including the pump in a suction tank.

Conventionally, as shown in FIG. 24, water 201 such as rainwater flows into a water sump 202 of a pumping station, is sucked up by a vertical shaft pump 203, and is sent from the water sump 202 to a downstream treatment facility. A standard suction tank 202 has a pair of side walls, a rear wall surface 205 and a bottom surface 206 , and a suction port 208 of the pump 203 is provided in the suction tank 202 and on the front side of the rear wall surface 205 .

By operating the pump 203, the water 201 in the suction tank 202 flows into the pump 203 from the suction port 208, passes through the pump 203, and is sent to the downstream treatment facility. During operation of the pump 203 , an underwater vortex 211 and an air intake vortex 212 may be generated in the suction tank 202 .

The underwater vortex 211 is a vortex generated from the bottom surface 206 or the side wall surface of the suction tank 202 and is sucked into the suction port 208 when the pressure of the vortex flow drops below the vapor pressure. The air-sucking vortex 212 is a vortex generated from the water surface toward the suction port 208 and entrains air on the water surface to be sucked into the suction port 208 .

If such underwater vortex 211 or air suction vortex 212 is sucked into the pump 203 through the suction port 208, there is a possibility that the pump 203 may generate violent vibrations and loud noises during operation.

In order to suppress the occurrence of the underwater vortex 211 and the air-sucking vortex 212 as described above, there is a general technique of installing an eddy current prevention plate (not shown) on the rear wall surface 205 and the bottom surface 206 of the suction tank 202. In addition to such a technique, for example, as shown in FIGS.

The vortex suppression member 220 includes a mounting flange 222 joined to the lower end of the bell mouth 221 , an arc wall 223 extending downward from the mounting flange 222 and curved in an arc shape, and between both ends of the arc wall 223 in the circumferential direction 227 . A flat baffle plate 224 is provided. The circular arc wall 223 and the baffle plate 224 form a cylindrical body 225 that is open in both vertical directions.

According to this, when the pump 203 is in operation, the circular arc wall 223 of the vortex suppressing member 220 passes the side of the pump 203 from the upstream side near the water surface, and the rear wall surface 205 of the suction tank 202 from behind the pump 203. After descending along , it becomes a resistance to the flows F1, F1' 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 down, the velocity of the downward flow F1' descending along the rear wall surface 205 from behind the casing 226 of the pump 203 decreases, and the velocity near the suction port 208 decreases. Since the vorticity is reduced, the generation of underwater vortices is suppressed.

Further, the flow F2 near the bottom surface 206 of the suction tank 202 approaches the pump 203 from the front upstream side 214 and flows into the suction port 208. At this time, the water 201 immediately before flowing into the suction port 208 collides with the baffle plate 224. Thus, the generation of swirling flow is prevented, and the generation of underwater vortices is effectively suppressed.

In addition, as described above, the arc wall 223 of the vortex suppressing member 220 acts as a resistance against the downward flow F1' that descends along the rear wall surface 205 from behind the casing 226. Since the flow F3 that descends and is sucked into the suction port 208 increases, and the downward flow F1' that descends along the rear wall surface 205 from behind the casing 226 weakens, the occurrence of air suction vortices is also suppressed. As a result, it is possible to prevent the pump 1 from generating violent vibrations and loud noises during operation.

Incidentally, the vortex suppressing member 220 as described above is described in, for example, Patent Document 1 below.

JP 2019-157808

However, in the above-described conventional type, the flow rate during operation of the vertical shaft pump 203 is set to a predetermined flow rate. It becomes difficult to sufficiently suppress the generation of air-sucking vortices, and there is a risk that underwater eddies and air-sucking vortices may occur.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vortex suppressing member, a pump, and pumping equipment that can sufficiently suppress the generation of underwater vortices and air entrainment 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,
an arc wall curved in an arc extending downward from a part of the periphery of the suction port of the bell mouth;
a bottom plate supported by the arc wall and facing downward to the suction port;
The bottom plate is arranged on the extension line of the axis of the bell mouth,
A flow path is formed from below the arcuate wall to above the arcuate wall through between the arcuate wall and the bottom plate.

According to this, the vortex suppressing member is attached to the bell mouth, and the pump is operated with the arc wall of the vortex suppressing member opposed to the rear wall surface of the suction tank. As a result, the arc wall acts as a resistance to the flow (flow near the surface of the water) that passes through the side of the pump from the front upstream side, descends along the rear wall surface from behind the pump, and is sucked into the suction port. Therefore, the amount of water sucked into the suction port from the rear wall surface side of the suction tank becomes smaller than the amount of water sucked into the suction port from the front upstream side of the suction tank. In this way, the arc wall acts as a resistance against the flow that descends from behind the pump along the rear wall surface, so that the flow that descends from near the water surface on the upstream side of the pump and is sucked into the suction port increases. Since the flow that descends along the rear wall surface from behind weakens, the generation of air entrainment vortices is suppressed.

In addition, since underwater vortices tend to occur near the extension of the axis of the bell mouth, the generation of underwater vortices can be sufficiently suppressed by arranging the bottom plate on the extension of the axis of the bell mouth.

Further, when part of the water in the suction tank flows from below the arcuate wall of the vortex suppressing member through the flow path into the suction port of the pump, it passes between the arcuate wall and the bottom plate from bottom to top. This prevents the bottom plate of the vortex suppressing member from covering the lower part of the suction port of the pump with the bottom plate of the vortex suppressing member, resulting in an excessive pressure loss (that is, reducing the pump efficiency). It is possible to prevent the occurrence of vortices in other places due to excessive flow velocity.

In the vortex suppressing member in the second aspect of the present invention, a partition wall that partitions the inside of the arc wall is provided on the arc wall,
The bottom plate is attached to the partition wall.

According to this, the flow near the bottom of the suction sump approaches the pump from the front upstream side and flows into the suction port of the bell mouth. generation is prevented, and the generation of underwater eddies is sufficiently suppressed.

The vortex suppressing member in the third aspect of the present invention is one in which the upper end of the partition wall is lower than the upper end of the arc wall.

According to this, the amount of flow flowing from the upstream side of the suction sump to the inside of the arc wall through the upper part of the partition wall increases, so the flow that descends from behind the pump along the rear wall surface of the suction sump further increases. weakening, which sufficiently suppresses the generation of air entrainment vortices.

In the vortex suppressing member of the fourth aspect of the present invention, the bottom plate is located inside the suction port when viewed from the axial direction of the bellmouth.

The vortex suppressing member in the fifth aspect of the present invention has a bottom plate attached to the arcuate wall.

The vortex suppressing member according to the sixth aspect of the present invention is provided with a lower projecting member projecting toward the inside of the arcuate wall at the lower end of the arcuate wall.

According to this, part of the water in the suction sump descends from the water surface along the rear wall surface behind the pump, passes through the arc wall of the vortex suppressing member, and is sucked into the suction port for a distance of: Compared to the case where the lower projecting member is not provided, the distance corresponding to the projecting width of the lower projecting member is extra. This increases the resistance when water flows from the rear wall side of the suction tank to the suction port through the inner side of the arcuate wall of the vortex suppressing member, further reducing the flow rate of water sucked into the suction port from the rear wall side. Since the flow descending along the rear wall surface from behind is further weakened, the generation of the air entrainment vortex is sufficiently suppressed.

A seventh invention is a pump comprising the vortex suppressing member according to any one of the first to sixth inventions,
A vortex suppression member is attached to the bellmouth.

An eighth invention is a pump facility comprising the pump according to the seventh invention in a 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 surface of the suction tank,
The arcuate wall of the vortex suppressing member faces the rear wall surface of the water suction tank.

As described above, according to the present invention, it is possible to sufficiently suppress the generation of underwater vortices and air entrainment vortices.

It is a side view of a pump in a 1st embodiment of the present invention. FIG. 2 is a view taken along line XX in FIG. 1; Fig. 3 is an enlarged cross-sectional view of a joint portion between a bell mouth and a vortex suppressing member of the pump; It is a figure when the vortex suppressing member of the pump is seen obliquely from above. It is a figure when the vortex suppressing member of the pump is seen obliquely from below. It is a top view of the vortex suppressing member of the same pump. FIG. 7 is a view taken along line XX in FIG. 6; It is a bottom view of the vortex suppressing member of the same pump. FIG. 8 is a view taken along line XX in FIG. 7; FIG. 10 is a diagram showing a water flow and an approaching flow velocity distribution in the suction sump when the pump is in operation. It is a figure when the vortex suppression member of the pump in the 2nd Embodiment of this invention is seen from the diagonally downward direction. Fig. 3 is a cross-sectional view of a vortex suppressing member of the pump; It is a figure when the vortex suppression member of the pump in the 3rd Embodiment of this invention is seen from diagonally above. It is a figure when the vortex suppressing member of the pump is seen obliquely from below. Fig. 3 is a cross-sectional view of a vortex suppressing member of the pump; It is a figure when the vortex suppression member of the pump in the 4th Embodiment of this invention is seen from diagonally above. It is a figure when the vortex suppressing member of the pump is seen obliquely from below. Fig. 3 is a cross-sectional view of a vortex suppressing member of the pump; It is a figure when the vortex suppression member of the pump in the 5th Embodiment of this invention is seen from diagonally above. It is a figure when the vortex suppressing member of the pump is seen obliquely from below. It is a top view of the vortex suppressing member of the same pump. FIG. 22 is a view taken along line XX in FIG. 21; It is a bottom view of the vortex suppressing member of the same pump. 1 is a schematic diagram of a conventional pump and a suction sump; FIG. FIG. 10 is a diagram showing the water flow and the approaching flow velocity distribution in the suction sump when the pump provided with the conventional vortex suppressing member is in operation; It is a figure when the conventional vortex suppression member is seen obliquely from below.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
In the first embodiment, as shown in FIGS. 1 and 2, 1 is a pump facility installed at a pumping station. and a pump 10 for drawing up water 3 and sending it to a downstream treatment facility.

The water intake sump 2 is of 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 of the pump 10.

The pump 10 is a vertical shaft pump and has a pump body 11 and a vortex suppressing member 12 . The pump body 11 has a vertically extending casing 14 , a rotatable main shaft 15 inserted through 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 . ing.

The casing 14 includes a straight pumping pipe 19 , a pump case 20 connected to the lower end of the pumping pipe 19 , a bell mouth 21 connected to the lower end of the pump case 20 , and a discharge port connected to the upper end of the pumping pipe 19 . an elbow 22; As shown in FIGS. 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 provided in the water suction tank 2 and is located on the front side (upstream side) of the rear wall surface 7 .

As shown in FIGS. 4 to 9, the vortex suppression member 12 is detachably attached to the lower end of the bell mouth 21 and has an arcuate shape extending downward from a portion of the peripheral edge of the suction port 23 of the bell mouth 21. A curved arc wall 30, an annular mounting flange 31 (an example of a mounting member) provided at the upper end of the arc wall 30, and two (a plurality of) partition walls 32 partitioning the inside of the arc wall 30, 33 and a bottom plate 34 supported by the arc wall 30 via partition walls 32 and 33 .

As shown in FIGS. 1 and 2 , the arcuate wall 30 faces the rear wall surface 7 of the water suction tank 2 . Further, as shown in FIG. 3, the mounting flange 31 is detachably joined to the flange 24 of the bell mouth 21 with a plurality of bolts 36. As shown in FIG.

Both partition walls 32 and 33 are plate-like members arranged in parallel. Thereby, a cylindrical body 38 surrounded by the arc wall 30 and the first partition wall 32 and open in both upper and lower directions is formed. Also, the second partition wall 33 is provided inside the cylindrical body 38 .

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

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, faces the suction port 23 of the bell mouth 21 below, and It is arranged on an extension line of the core 40 .

A lower end portion 30b of the arc wall 30 is provided with a lower projecting member 41 that projects inward in the radial direction of the arc wall 30 . The lower projecting member 41 is formed in a C shape when viewed from the axial direction (vertical 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 when viewed from the axial direction of the bell mouth 21 . Circulation passages 42 a , 42 b , 42 c are formed that extend from below the arc wall 30 to above the arc wall 30 through between the arc wall 30 and the bottom plate 34 .

The operation of the above configuration will be described below.

When the pump 10 is operated, the impeller 16 (see FIG. 1) rotates, and the water 3 in the suction tank 2 is sucked into the casing 14 through the suction port 23 of the bellmouth 21 and through the discharge elbow 22. It is sent to a downstream treatment facility. At this time, as shown in FIG. 10, the arc wall 30 of the vortex suppressing member 12 acts as a resistance against the flows F1 and F1', so that the velocity V1 of the flow F1 of the water 3 near the water surface slows down, and The speed of the descending flow F1' descending along the rear wall surface 7 decreases. This reduces the vorticity in the vicinity of the suction port 23 and suppresses the generation of underwater vortices.

The flow F2 near the bottom surface 8 of the suction tank 2 approaches the pump 10 from the front upstream side 9 and flows into the suction port 23. At this time, the water 3 immediately before flowing into the suction port 23 flows into the first and second partitions. By colliding with at least one of the walls 32 and 33, generation of a swirling flow is prevented, and generation of an underwater vortex is more effectively suppressed.

Furthermore, since underwater vortices are likely to occur near the extension of the axis 40 of the bell mouth 21, the bottom plate 34 is arranged on the extension of the axis 40 of the bell mouth 21 to sufficiently suppress the generation of underwater vortices. be able to.

Further, as described above, the circular arc wall 30 of the vortex suppressing member 12 acts as a resistance to the downward flow F1', and as shown in FIG. Since the flow F3 sucked into the casing 14 increases and the descending flow F1' descending along the rear wall surface 7 from behind the casing 14 weakens, the generation of the air sucking vortex is also suppressed.

Further, as shown in FIG. 7, the upper ends 32a, 33a of the first and second partition walls 32, 33 of the vortex suppressing member 12 are positioned lower than the upper end 30a of the arcuate wall 30. The amount of flow flowing from the front upstream side 9 to the inside of the arcuate wall 30 through above the first or second partition walls 32 and 33 increases, and the amount flows from behind the pump 10 along the rear wall surface 7 of the suction tank 2. The descending downward flow F1' weakens further. This sufficiently suppresses the generation of air entrainment vortices.

Further, as shown in FIG. 10, part of the water 3 in the suction tank 2 descends from the water surface along the rear wall surface 7 behind the pump 10, and then, as shown in FIGS. The air is sucked into the suction port 23 of the bell mouth 21 through the twelve flow paths 42a, 42b, and 42c. At this time, as shown in FIG. The flow distance is equivalent to the overhang width W of the lower overhang member 41 in the radial direction of the arc wall 30 compared to the case where the lower overhang member 41 is not provided (see FIG. 12 of a second embodiment described later). extra long by the distance to

This increases the resistance when the water 3 flows from the rear wall surface 7 side to the suction port 23 through the inside of the arc wall 30 (that is, the inside of the cylindrical body 38), and is sucked into the suction port 23 from the rear wall surface 7 side. Since the flow rate is further reduced and the downward flow F1' (see FIG. 10) descending along the rear wall surface 7 from behind the pump 10 is further weakened, the generation of the air intake vortex is further suppressed.

Further, when part of the water 3 in the suction tank 2 flows from below the arcuate wall 30 of the vortex suppressing member 12 through the flow passages 42a, 42b, and 42c into the suction port 23 of the pump 10, the arcuate wall 30 and the bottom plate 34 from bottom to top. As a result, it is possible to prevent the bottom plate 34 of the vortex suppressing member 12 from covering the suction port 23 of the pump 10 with the bottom plate 34 of the vortex suppressing member 12, thereby preventing the pressure loss from becoming excessive (that is, reducing the pump efficiency). It is possible to prevent the local flow velocity on the upstream side 9 from excessively increasing and generating a vortex at another location.

As a result, for example, even when the pump 10 is operated with a flow rate greater than a predetermined flow rate without changing the diameter of the pump 10, it is possible to sufficiently suppress the occurrence of underwater vortices and air-sucking vortices. It is possible to prevent violent vibrations and loud noises from occurring.

(Second embodiment)
In the first embodiment described above, the lower projecting member 41 is provided at the lower end of the arcuate wall 30 as shown in FIG. 7, but in the second embodiment, as shown in FIGS. , the lower projecting member 41 is not provided.

According to this, the same actions and effects as those of the first embodiment described above can be obtained.

(Third Embodiment)
In the first embodiment described above, the bottom plate 34 and the lower projecting member 41 are separated as shown in FIGS. 7 and 8, but in the third embodiment, as shown in FIGS. In addition, the bottom plate 34 and the lower projecting member 41 are integrally connected. The lower projecting member 41 is formed in a sector shape when viewed from the axial direction (vertical direction) of the bell mouth 21 . A fan-shaped region surrounded by the lower end portion 30b of the arc wall 30 and the lower end portion 33b of the second partition wall 33 is closed by the lower projecting member 41. As shown in FIG.

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

Circulation passages 42b and 42c are formed from below the arcuate wall 30 to above the arcuate wall 30 through between the arcuate wall 30 and the bottom plate 34 .

According to this, since the flow passage 42a shown in FIG. 4 of the first embodiment is closed by the lower projecting member 41, part of the water 3 in the suction tank 2 flows from the water surface to the rear of the pump 10. After descending along the rear wall surface 7, the air is sucked into the suction port 23 of the bell mouth 21 through the flow passages 42b and 42c instead of the flow passage 42a of the vortex suppressing member 12 as shown in FIGS. At this time, as shown in FIG. 15, the distance of the flow through the flow passages 42b and 42c until it is sucked into the suction port 23 is the same as in the case where the lower projecting member 41 is not provided (as in the above-described second embodiment). 12), it is extra long by a distance corresponding to the extension width W of the lower extension member 41 in the front-rear direction.

This increases the resistance when the water 3 flows into the suction port 23 from the rear wall surface 7 side through the arc wall 30 (that is, the cylindrical body 38), and is drawn into the suction port 23 from the rear wall surface 7 side. The amount of air drawn in is further reduced, and the downward flow F1' (see FIG. 10) descending along the rear wall surface 7 from behind the pump 10 is further weakened, thereby further suppressing the occurrence of the air intake vortex.

In addition, as in the first embodiment described above, the generation of underwater vortices is further suppressed.

(Fourth embodiment)
In the third embodiment described above, the bottom plate 34 is provided at the same height as the lower projecting member 41 as shown in FIG. 15, but in the fourth embodiment, as shown in FIGS. Moreover, the bottom plate 34 is provided at a position higher than the lower projecting member 41 . Upper ends 32a and 33a of the first and second partition walls 32 and 33 are approximately the same height as the upper end 30a of the arc wall 30, respectively. Furthermore, lower ends 32b and 33b of the first and second partition walls 32 and 33 are higher than the lower end 30b of the arc wall 30, respectively.

Circulation passages 42 a , 42 b , 42 c extending from below the arc wall 30 to above the arc wall 30 through between the arc wall 30 and the bottom plate 34 are formed.

According to this, part of the water 3 in the suction tank 2 descends from the water surface along the rear wall surface 7 behind the pump 10, and then passes through the flow passages 42a, 42b, 42c of the vortex suppressing member 12 to reach the bell mouth 21. At this time, as shown in FIG. 18, the distance of the flow through the flow passage 42a until it is sucked into the suction port 23 is the same as in the case where the lower projecting member 41 is not provided ( 12 of the second embodiment described above), the distance corresponding to the extension width W of the lower extension member 41 in the front-rear direction is extra. This increases the resistance when the water 3 flows into the suction port 23 from the rear wall surface 7 side through the arc wall 30 (that is, the cylindrical body 38), and is drawn into the suction port 23 from the rear wall surface 7 side. The amount of air drawn in is further reduced, and the downward flow F1' (see FIG. 10) descending along the rear wall surface 7 from behind the pump 10 is further weakened, thereby further suppressing the occurrence of the air intake vortex.

18, since the lower ends 32b, 33b of the first and second partition walls 32, 33 are located above the lower end 30b of the arcuate wall 30, the water from the upstream side 9 of the suction tank 2 The amount of flow flowing inside the arcuate wall 30 (that is, inside the cylindrical body 38) through the lower side of the first or second partition walls 32, 33 increases, and the rear wall surface 7 of the suction tank 2 from behind the pump 10 increases accordingly. The descending flow F1' (see FIG. 10) descending along is further weakened. This sufficiently suppresses the generation of air entrainment vortices.

In each of the first to fourth embodiments, as shown in FIGS. 7, 12, and 15, the upper ends 32a and 33a of the first and second partition walls 32 and 33 are separated from the upper end 30a of the arcuate wall 30. As shown in FIGS. Alternatively, as shown in FIG. 18, the lower ends 32b and 33b of the first and second partition walls 32 and 33 are positioned higher than the lower end 30b of the arc wall 30, but the first and second The upper ends 32a, 33a of the second partition walls 32, 33 are at the same height as 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 positioned at the lower end of the arc wall 30. It may have the same height as the portion 30b.

(Fifth embodiment)
In the fifth embodiment, as shown in FIGS. 19 to 23, the arcuate wall 30 is provided with one (single) partition wall 60 that partitions the inside of the arcuate wall 30 . The bottom plate 34 is a substantially rectangular flat plate, and both short side edges 34a of the bottom plate 34 are attached to the inside of the arc wall 30, and one long side edge 34b of the bottom plate 34 is attached to the lower end 60b of the partition wall 60. ing.

As shown in FIG. 22 , the bottom plate 34 is provided at a position higher than the lower projecting member 41 . Also, the upper end portion 60a of the partition wall 60 is substantially the same height as the upper end portion 30a of the arc wall 30. As shown in FIG. Furthermore, the lower end portion 60b of the partition wall 60 is higher than the lower end portion 30b of the arc wall 30. As shown in FIG. As a result, a tubular body 38 surrounded by the arc wall 30 and the partition wall 60 and open in both upper and lower directions is formed.

A flow path 42 is formed from below the arc wall 30 to above the arc wall 30 through between the arc wall 30 and the bottom plate 34 .

According to this, since underwater vortices are likely to occur near the extension of the axis 40 of the bell mouth 21, the bottom plate 34 is placed on the extension of the axis 40 of the bell mouth 21 to sufficiently prevent the generation of underwater vortices. can be suppressed.

Also, as shown in FIG. 22, after part of the water 3 in the suction tank 2 descends from the water surface along the rear wall surface 7 behind the pump 10, it passes through the flow passage 42 and enters the suction port 23 of the bell mouth 21. The distance of the flow until it is sucked in corresponds to the projecting width W of the lower projecting member 41 in the front-rear direction, compared to the case where the lower projecting member 41 is not provided (see FIG. 12 of the above-described second embodiment). extra long by the distance to This increases the resistance when the water 3 flows into the suction port 23 from the rear wall surface 7 side through the arc wall 30 (that is, the cylindrical body 38), and is drawn into the suction port 23 from the rear wall surface 7 side. The amount of air drawn in is further reduced, and the downward flow F1' (see FIG. 10) descending along the rear wall surface 7 from behind the pump 10 is further weakened, thereby further suppressing the occurrence of the air intake vortex.

In addition, the flow rate from the front upstream side 9 of the suction tank 2 to the inside of the arcuate wall 30 (that is, the inside of the cylindrical body 38) through the bottom plate 34 and the partition wall 60 is increased. A downward flow F1' (see FIG. 10) descending along the rear wall surface 7 of the water suction sump 2 from behind is further weakened. This sufficiently suppresses the generation of air entrainment vortices.

In each of the above-described embodiments, as shown in FIG. 3, the vortex suppressing member 12 is detachably attached to the lower end of the bell mouth 21 using the bolt 36. 21 may be integrally attached to the lower end. In this case, the arcuate wall 30 of the vortex suppressing member 12 may not be provided with the mounting flange 31 and the upper end 30a of the arcuate wall 30 may be welded to the lower end of the bell mouth 21 .

In each of the above embodiments, the bottom plate 34 has a rectangular shape, but the shape of the bottom plate 34 may be a circle, an ellipse, a polygon other than a square, or the like.

In each of the above-described embodiments, the bottom plate 34 is provided at the same position as the lower end 30b of the circular arc wall 30 or at a position above the lower end 30b, but is provided at a lower position than the lower end 30b. may

1 pump equipment 2 suction tank 7 rear wall surface 10 pump 12 vortex suppressing member 21 bell mouth 23 suction port 30 arc wall 30a arc wall upper end portions 32, 33 partition walls 32a, 33a partition wall upper end portion 34 bottom plate 40 axis 41 lower portion Projecting members 42, 42a, 42b, 42c Flow path

Claims (8)

A vortex suppression member attachable to a bell mouth of a pump, comprising:
an arc wall curved in an arc extending downward from a part of the periphery of the suction port of the bell mouth;
a bottom plate supported by the arc wall and facing downward to the suction port;
The bottom plate is arranged on the extension line of the axis of the bell mouth,
A vortex suppressing member, characterized in that a flow path is formed from below the arcuate wall to above the arcuate wall through between the arcuate wall and the bottom plate. A partition wall that partitions the inside of the arc wall is provided in the arc wall,
The vortex suppressing member of claim 1, wherein the bottom plate is attached to the partition wall. 3. A vortex suppressing member according to claim 2, wherein the upper end of the partition wall is lower than the upper end of the arcuate wall. 4. The vortex suppressing member according to any one of claims 1 to 3, wherein the bottom plate is located inside the suction port when viewed from the axial direction of the bell mouth. A vortex suppressing member according to any one of claims 1 to 3, wherein the bottom plate is attached to the arcuate wall. 6. The vortex suppressing member according to any one of claims 1 to 5, wherein a lower end portion of the arcuate wall is provided with a lower projecting member projecting inwardly of the arcuate wall. A pump comprising the vortex suppressing member according to any one of claims 1 to 6,
A pump, wherein a vortex suppressing member is attached to the bellmouth. A pump facility comprising the pump according to claim 7 in a 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 surface of the suction tank,
A pump facility characterized in that an arcuate wall of the vortex suppressing member faces a rear wall surface of the suction sump.

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