Vortex suppression members, pumps and pumping equipment

Abstract

To provide a vortex suppression member capable of sufficiently suppressing the occurrence of underwater vortexes or air intake vortexes.SOLUTION: A vortex suppression member 12 which can be mounted to a bell mouth of a pump is provided, including 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 lower protrusion member 41 protruding from a lower end 30b of the circular-arc wall 30 to the inside of the circular-arc wall 30.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a vortex suppression member that suppresses the generation of vortices, a pump equipped with the vortex suppression member, and a pump facility equipped with a pump in a suction tank. [Background technology]

[0002] Conventionally, as shown in Figure 24, water 201, such as rainwater, flows into a suction tank 202 at a pumping station, is sucked 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 provided inside the suction tank 202, on the near side of the rear wall 205.

[0003] By operating pump 203, water 201 in suction tank 202 flows into pump 203 from suction port 208 and is sent to a downstream treatment facility through pump 203. When pump 203 is operating, a submerged vortex 211 and an air-sucking vortex 212 may occur in suction tank 202.

[0004] The underwater vortex 211 is a vortex generated from the bottom surface 206 or the side wall surface 204 of the suction tank 202, the pressure of which drops below the steam pressure and is sucked into the suction port 208. The air-sucking vortex 212 is a vortex generated from the water surface toward the suction port 208, which entrains air above the water surface and is sucked into the suction port 208.

[0005] If such underwater vortex 211 or air-sucking vortex 212 is sucked into the pump 203 through the suction port 208, there is a risk that severe vibrations and loud noises will occur during operation of the pump 203.

[0006] In order to suppress the occurrence of the underwater vortex 211 and the air-sucking vortex 212 as 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 be attached to the bell mouth 221 of the vertical pump 203, as shown in FIGS. 25 and 26.

[0007] The vortex suppression member 220 has a mounting flange 222 joined to the lower end of the bellmouth 221, an arc wall 223 that curves in an arc shape and extends downward from the mounting flange 222, and a flat baffle plate 224 provided between both end portions in the circumferential direction 227 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.

[0008] According to this, when the pump 203 is operating, the arc 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, F1' that are sucked into the suction port 208.

[0009] As a result, the velocity V1 of the flow F1 of the water 201 near the water surface slows down, 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.

[0010] Furthermore, flow F2 near bottom surface 206 of suction tank 202 approaches pump 203 from upstream side 214 and flows into suction port 208. At this time, water 201 just before flowing into suction port 208 collides with baffle plate 224, preventing the generation of a swirling flow and effectively suppressing the generation of underwater vortices.

[0011] Furthermore, as described above, the arcuate wall 223 of the vortex suppression member 220 provides resistance to the downward flow F1' that descends from behind the casing 226 along the rear wall surface 205, thereby increasing the flow F3 that descends from near the water surface on the front upstream side 214 of the casing 226 and is sucked into the suction port 208, and weakening the downward flow F1' that descends from behind the casing 226 along the rear wall surface 205, thereby suppressing the generation of an air-sucking vortex. This makes it possible to prevent the pump 1 from generating severe vibrations and loud noises during operation.

[0012] The vortex suppression member 220 as described above is described in, for example, Patent Document 1 listed below. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Patent Publication No. 2019-157808 Summary of the Invention [Problem to be solved by the invention]

[0014] However, in the above-described conventional type, the flow rate of the vertical shaft pump 203 during operation is set to a predetermined flow rate. However, for example, if the flow rate is increased beyond the predetermined flow rate and the vertical shaft 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.

[0015] An object of the present invention is to provide a vortex suppression member, a pump, and a pump facility that can sufficiently suppress the occurrence of underwater vortices and air-sucking vortices. [Means for solving the problem]

[0016] 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 shape extending downward from a part of the peripheral edge of the suction port of the bell mouth; a lower protruding member protruding from a lower end of the arc wall toward the inside of the arc wall, When viewed from the axial direction of the bell mouth, the arc wall is formed in a C shape, an opening communicating with the inside and outside of the arc wall is formed between both end portions of the arc wall in the circumferential direction; When viewed from the axial direction of the bell mouth, the lower protruding member is , C-shaped or fan-shaped, It extends to the area inside the suction port of the bell mouth.

[0017] 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 from the upstream side of the pump, descends along the rear wall from behind the pump, and is then drawn into the suction port. As a result, the amount of water drawn into the suction port from the rear wall of the sump is less than the amount of water drawn into the suction port from the upstream side 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 of the pump and drawn into the suction port increases, while the flow descending along the rear wall from behind the pump weakens, thereby suppressing the generation of air-intake vortices.

[0018] Furthermore, the distance that some of the water in the suction sump travels, after descending from the water surface along the rear wall behind the pump, passing through the inside of the arc-shaped wall before being sucked into the suction port, is longer by a distance equivalent to the overhang width of the lower overhanging member, compared to when the lower overhanging member is not provided. This increases the resistance to water flowing from the rear wall of the suction sump through the inside of the arc-shaped wall of the vortex suppression member and into the suction port, further reducing the flow rate sucked into the suction port from the rear wall and further weakening the flow descending along the rear wall from behind the pump, thereby sufficiently suppressing the occurrence of air-intake vortices.

[0019] In the vortex suppression member according to the second aspect of the present invention, a partition wall that partitions the inside of the arc-shaped wall is provided on the arc-shaped wall, A cylindrical body is formed which is surrounded by an arc wall and a partition wall and is open on both the top and bottom sides.

[0020] The vortex suppression member in the third aspect of the present invention has a bottom plate facing the lower side of the suction port, which is attached to the partition wall, The bottom plate is disposed on the extension of the axis of the bell mouth.

[0021] According to this, since underwater vortices tend to occur near the extension of the axial center of the bell mouth, the occurrence of underwater vortices can be sufficiently suppressed by placing the bottom plate on the extension of the axial center of the bell mouth.

[0022] In the vortex suppression member according to the fourth aspect of the present invention, the upper end of the partition wall is located lower than the upper end of the arc wall.

[0023] This increases the flow rate flowing from the upstream side of the suction tank, passing over the partition wall and into the inside of the arc wall, thereby further weakening the flow flowing downward along the rear wall surface of the suction tank from behind the pump, thereby sufficiently suppressing the generation of air-sucking vortices.

[0024] The present invention provides a pump equipped with the vortex suppression member according to any one of the first to fourth aspects of the present invention, The vortex suppressor is attached to the bell mouth.

[0025] The present invention in a sixth aspect is a pump facility including the pump according to the fifth aspect 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. [Effects of the Invention]

[0026] As described above, according to the present invention, the occurrence of underwater vortices and air-sucking vortices can be sufficiently suppressed. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a side view of a pump according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a view taken along the arrow XX in FIG. [Figure 3] 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. [Figure 4] FIG. 2 is a view of the pump's vortex suppression member as viewed obliquely from above. [Figure 5] FIG. 2 is a view of the pump's vortex suppression member as viewed obliquely from below. [Figure 6] FIG. 2 is a plan view of the vortex suppression member of the pump according to the first embodiment. [Figure 7] 7 is a view taken along the arrow XX in FIG. 6. [Figure 8] FIG. 2 is a bottom view of the vortex suppression member of the pump according to the first embodiment. [Figure 9] 8 is a view taken along the arrow XX in FIG. 7. [Figure 10] 10A and 10B are diagrams showing the water flow and approach velocity distribution in the suction sump when the pump is operating. [Figure 11] 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 above. [Figure 12] FIG. 2 is a view of the pump's vortex suppression member as viewed obliquely from below. [Figure 13] FIG. 2 is a cross-sectional view of a vortex suppression member of the pump according to the first embodiment. [Figure 14] FIG. 10 is a diagram showing a vortex suppression member of a pump according to a third embodiment of the present invention, viewed obliquely from above. [Figure 15] FIG. 2 is a view of the pump's vortex suppression member as viewed obliquely from below. [Figure 16] FIG. 2 is a cross-sectional view of a vortex suppression member of the pump according to the first embodiment. [Figure 17] 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. [Figure 18] FIG. 2 is a view of the pump's vortex suppression member as viewed obliquely from below. [Figure 19] FIG. 2 is a plan view of the vortex suppression member of the pump according to the first embodiment. [Figure 20] 20 is a view taken along the arrow XX in FIG. 19. [Figure 21] FIG. 2 is a bottom view of the vortex suppression member of the pump according to the first embodiment. [Figure 22] FIG. 11 is a diagram showing a vortex suppression member of a pump according to a fifth embodiment of the present invention, viewed obliquely from below. [Figure 23] FIG. 2 is a cross-sectional view of a vortex suppression member of the pump according to the first embodiment. [Figure 24] FIG. 1 is a schematic diagram of a conventional pump and suction tank. [Figure 25]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. [Figure 26] FIG. 10 is a diagram of a conventional vortex suppression member viewed obliquely from below. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0029] (First embodiment) In the first embodiment, as shown in Figures 1 and 2, reference numeral 1 denotes a pump facility installed at a pumping station, and the pump facility 1 includes a water intake tank 2 and a pump 10 that sucks up water 3, such as rainwater, that has flowed into the water intake tank 2 and sends it to a downstream treatment facility.

[0030] 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, and water 3 flows in from an upstream side 9 in front of a pump 10.

[0031] Pump 10 is a vertical shaft pump and includes a pump body 11 and a vortex suppression member 12. Pump body 11 includes a casing 14 extending vertically, a rotatable main shaft 15 inserted into casing 14, an impeller 16 that rotates together with main shaft 15, and a rotary drive device 17 that rotates main shaft 15.

[0032] The casing 14 has a straight rise pipe 19, a pump case 20 connected to the lower end of the rise 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 rise 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 provided in the suction tank 2, and is located on the near side (upstream side) of the rear wall surface 7.

[0033] As shown in Figures 4 to 9, the vortex suppression member 12 is detachably attached to the lower end of the bell mouth 21, and has an arc wall 30 that is curved in an arc shape and extends downward from a part of the peripheral edge of the suction port 23 of the bell mouth 21, an annular mounting flange 31 (an example of a mounting member) provided at 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 that is supported by the arc wall 30 via the partition walls 32, 33, and a lower protruding member 41 that protrudes from the lower end of the arc wall 30 toward the inside of the arc wall 30.

[0034] 1 and 2, the arc wall 30 faces the rear wall surface 7 of the suction sump 2. Furthermore, as shown in FIG. 3, the mounting flange 31 is detachably joined to the flange 24 of the bell mouth 21 by a plurality of bolts 36.

[0035] The partition walls 32, 33 are flat plate-like members arranged in parallel, and of these, the first partition wall 32 is provided between both end portions 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 provided inside the cylindrical body 38.

[0036] 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.

[0037] 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, and is positioned opposite the lower side of the suction port 23 of the bell mouth 21 and on an extension of the axis 40 of the bell mouth 21.

[0038] As shown in FIGS. 6 and 8, the lower protruding member 41 protrudes inward in the radial direction of the arc wall 30, and is formed in a C-shape when viewed from the axial direction of the bell mouth 21 (vertical direction).

[0039] Furthermore, when viewed from the axial direction of the bell mouth 21, the bottom plate 34 is located inside the outline of the suction port 23 of the bell mouth 21. Flow passages 42a, 42b, 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.

[0040] The operation of the above configuration will now be described.

[0041] When the pump 10 is operated, the impeller 16 (see FIG. 1) rotates, and water 3 in the suction tank 2 is sucked into the casing 14 through the suction port 23 of the bell mouth 21 and sent to the downstream treatment facility through the discharge elbow 22 (see FIG. 1). At this time, as shown in FIG. 10, the arc wall 30 of the vortex suppression member 12 acts as resistance to the flows F1 and F1', slowing down the velocity V1 of the flow F1 of the water 3 near the water surface and reducing the velocity of the downward flow F1' that descends 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.

[0042] 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. At this time, the water 3 just before flowing into the suction port 23 collides with at least one of the first and second partition walls 32, 33, thereby preventing the generation of a swirling flow and more effectively suppressing the generation of underwater vortices.

[0043] Furthermore, since underwater vortices tend to occur near the extension of the axis 40 of the bell mouth 21, by positioning the bottom plate 34 on the extension of the axis 40 of the bell mouth 21, the occurrence of underwater vortices can be sufficiently suppressed.

[0044] Furthermore, as described above, the arcuate wall 30 of the vortex suppression member 12 acts as a resistance to the downward flow F1', and as a result, as shown in Figure 10, 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 increases, and the downward flow F1' that descends from behind the casing 14 along the rear wall surface 7 weakens, thereby suppressing the generation of an air-sucking vortex.

[0045] Furthermore, a portion of the water 3 in the sump 2 flows downward from the water surface along the rear wall surface 7 behind the pump 10, and then passes through the flow passages 42a, 42b, and 42c of the vortex suppression member 12 to be sucked into the suction port 23 of the bell mouth 21. At this time, as shown in FIG. 7, the distance that the water travels through the flow passage 42a to be sucked into the suction port 23 is longer than in the case where the lower protruding member 41 is not provided by a distance equivalent to the protruding width W of the lower protruding member 41 in the radial direction of the arc wall 30.

[0046] This increases the resistance when water 3 flows from the rear wall surface 7 side through the inside of the arc wall 30 (i.e., 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' that flows down along the rear wall surface 7 from behind the pump 10, thereby further suppressing the occurrence of an air-sucking vortex.

[0047] 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-shaped wall 30, so the flow rate of water flowing from the front upstream side 9 of the suction sump 2, passing above the first or second partition wall 32, 33, into the inside of the arc-shaped wall 30 increases, and the downward flow F1' that flows down from behind the pump 10 along the rear wall surface 7 of the suction sump 2 is further weakened accordingly. This sufficiently suppresses the generation of air-sucking vortices.

[0048] Furthermore, 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, 42c and 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 plate 34 of the vortex suppression member 12 from covering too much of the area below the suction port 23 of the pump 10, which would result in excessive pressure loss (i.e., a decrease in 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, which would result in the generation of vortices in other locations.

[0049] As a result, even if the flow rate is increased beyond a predetermined value without changing the diameter of the pump 10, the occurrence of underwater vortices and air-suction vortices can be sufficiently suppressed, and the occurrence of severe vibrations and loud noises from the pump 10 during operation can be prevented.

[0050] (Second 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 second embodiment, the bottom plate 34 and the lower overhanging member 41 are integrally connected as shown in Figures 11 to 13. 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 30b of the arc wall 30 and the lower end 33b of the second partition wall 33 is closed by the lower overhanging member 41.

[0051] In addition, the upper ends 32a, 33a of the first and second partition walls 32, 33 are respectively 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 respectively at the same height as the lower end 30b of the arc wall 30.

[0052] Flow passages 42b and 42c are formed that extend from below the arc wall 30 through between the arc wall 30 and the bottom plate 34 to above the arc wall 30.

[0053] According to this, since the flow passage 42a shown in FIG. 7 of the first embodiment is closed by the lower protruding member 41, a part of the water 3 in the suction tank 2 flows down from the water surface along the rear wall surface 7 behind the pump 10, and then is sucked into the suction port 23 of the bell mouth 21 through the flow passages 42b and 42c as shown in FIGS. 11 to 13, rather than through the flow passage 42a.

[0054] In this case, as shown in Figure 13, the distance the air travels through the flow passages 42b and 42c before being sucked into the suction port 23 is longer than when the lower extension member 41 is not provided by a distance equivalent to the extension width W of the lower extension member 41 in the front-to-rear direction.

[0055] This increases the resistance when water 3 flows from the rear wall surface 7 side through the inside of the arc wall 30 (i.e., 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' that flows down along the rear wall surface 7 from behind the pump 10, thereby further suppressing the occurrence of an air-sucking vortex.

[0056] Furthermore, similar to the first embodiment described above, the generation of underwater vortices is further suppressed.

[0057] (Third embodiment) In the second embodiment described above, as shown in Fig. 13, the bottom plate 34 is provided at the same height as the lower protruding member 41, but in the third embodiment, as shown in Figs. 14 to 16, the bottom plate 34 is provided at a higher position than the lower protruding member 41. In addition, the upper ends 32a and 33a of the first and second partition walls 32 and 33 are each at approximately the same height as the upper end 30a of the arc-shaped wall 30. Furthermore, the lower ends 32b and 33b of the first and second partition walls 32 and 33 are each higher than the lower end 30b of the arc-shaped wall 30.

[0058] In addition, flow passages 42a, 42b, and 42c are formed that pass from below the arc wall 30 through between the arc wall 30 and the bottom plate 34 and exit above the arc wall 30.

[0059] According to this configuration, a portion 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 the flow passages 42a, 42b, and 42c of the vortex suppression member 12 before being sucked into the suction port 23 of the bell mouth 21. At this time, as shown in Fig. 16, the distance that the water flows through the flow passage 42a before being sucked into the suction port 23 is longer by a distance corresponding to the overhang width W of the lower overhang member 41 in the front-to-rear direction than when the lower overhang member 41 is not provided. This increases the resistance when the water 3 flows from the rear wall surface 7 side through the inside of the arcuate wall 30 (i.e., the inside of the cylindrical body 38) into the suction port 23, further reducing the flow rate of the water 3 sucked into the suction port 23 from the rear wall surface 7 side. This further weakens the downward flow F1' that flows downward along the rear wall surface 7 from behind the pump 10, thereby further suppressing the generation of an air-intake vortex.

[0060] Furthermore, 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-shaped wall 30, the flow rate of water flowing from the upstream side 9 of the suction sump 2, passing below the first or second partition wall 32, 33, into the inside of the arc-shaped wall 30 increases, and the downward flow F1' that flows down from behind the pump 10 along the rear wall surface 7 of the suction sump 2 is further weakened accordingly. This sufficiently suppresses the generation of an air-sucking vortex.

[0061] In each of the above first to third embodiments, as shown in Figures 7, 13, and 16, 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, or the lower ends 32b, 33b of the first and second partition walls 32, 33 are higher than the lower end 30b of the arc wall 30, but the upper ends 32a, 33a of the first and second partition walls 32, 33 may be 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 may be at the same height as the lower end 30b of the arc wall 30.

[0062] (Fourth embodiment) 17 to 21 , in the fourth embodiment, one (single) partition wall 60 that separates the inside of the arc wall 30 is provided on the arc wall 30. The bottom plate 34 is a generally 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 a lower end 60b of the partition wall 60.

[0063] 20, the bottom plate 34 is located at a higher position than the lower overhanging member 41. 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. The lower end 60b of the partition wall 60 is located higher than the lower end 30b of the arc wall 30. This forms a cylindrical body 38 that is surrounded by the arc wall 30 and the partition wall 60 and is open on both the top and bottom sides.

[0064] A flow passage 42 is formed that passes from below the arc wall 30 between the arc wall 30 and the bottom plate 34 and leads to above the arc wall 30.

[0065] 20, the distance that water 3 in suction sump 2 travels from the water surface down along rear wall surface 7 behind pump 10 through flow passage 42 to be sucked into suction port 23 of bell mouth 21 is longer by a distance equivalent to the overhang width W of lower overhang member 41 in the front-to-rear direction, compared to when lower overhang member 41 is not provided. This increases the resistance of water 3 when it flows from the rear wall surface 7 side through the inside of arcuate wall 30 (i.e., the inside of cylindrical body 38) into suction port 23, further reducing the flow rate sucked into suction port 23 from the rear wall surface 7 side and further weakening downward flow F1' that flows down along rear wall surface 7 from behind pump 10, thereby further suppressing the occurrence of an air-sucking vortex.

[0066] Furthermore, the flow rate flowing from the upstream side 9 of the suction sump 2 to the inside of the arc-shaped wall 30, passing below the bottom plate 34 and below the partition wall 60, increases, and the downward flow F1' flowing down from behind the pump 10 along the rear wall surface 7 of the suction sump 2 is further weakened accordingly. This sufficiently suppresses the generation of an air-sucking vortex.

[0067] (Fifth embodiment) In the first embodiment described above, the vortex suppression member 12 has the arc wall 30, the mounting flange 31, the partition walls 32 and 33, the bottom plate 34, and the lower protruding member 41. However, in the fifth embodiment, as shown in FIGS. 22 and 23 , the vortex suppression member 12 does not have the partition walls 32 and 33 or the bottom plate 34, but only has the arc wall 30, the mounting flange 31, and the lower protruding member 41.

[0068] The lower protruding member 41 is formed in a fan shape when viewed from the axial direction (vertical direction) of the bell mouth 21, and is provided over the entire area inside the lower end portion 30b of the arc-shaped wall 30, and has an arc-shaped outer peripheral edge 41a and a linear outer peripheral edge 41b. The outer peripheral edge 41b of the lower protruding member 41 is located between both end portions of the arc-shaped wall 30 in the circumferential direction 37.

[0069] As a result, a portion 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 from the outside to the inside of the arc-shaped wall 30 and flows into the suction port 23 of the bell mouth 21. At this time, as shown in Fig. 23 , the distance the water flows from the outside to the inside of the arc-shaped wall 30 until it is sucked into the suction port 23 is longer by a distance corresponding to the overhang width W of the lower overhang member 41 in the front-to-rear direction, compared to when the lower overhang member 41 is not provided. This increases the resistance of the water 3 when it flows from the rear wall surface 7 side through the inside of the arc-shaped wall 30 and into the suction port 23, further reducing the flow rate sucked into the suction port 23 from the rear wall surface 7 side. This further weakens the downward flow F1' that flows downward along the rear wall surface 7 from behind the pump 10, thereby further suppressing the generation of an air-intake vortex.

[0070] 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 bell mouth 21 using bolts 36, but the vortex suppression member 12 may also be attached integrally to the lower end of the bell mouth 21 by welding or the like. In this case, the attachment flange 31 may not be provided on the arc-shaped wall 30 of the vortex suppression member 12, and the upper end of the arc-shaped wall 30 of the vortex suppression member 12 may be welded to the lower end of the bell mouth 21.

[0071] In the above-described embodiments, the bottom plate 34 is rectangular, but the shape of the bottom plate 34 may be circular, elliptical, or any other polygonal shape other than a square.

[0072] In each of the above embodiments, the bottom plate 34 is located at the same position as the lower end 30b of the arc wall 30 or at a position above the lower end 30b, but it may also be located at a position below the lower end 30b. [Explanation of symbols]

[0073] 1. Pump equipment 2 Water absorption tank 7 Rear wall 10 Pump 12 Vortex suppression member 21 Bellmouth 23 Intake port 30 Arc Wall 30a Upper end of arc wall 32,33 Partition wall 32a, 33a Upper end of partition wall 34 Bottom plate 38 Cylinder 40 axis 41 Lower extension member

Claims

1. 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 lower protruding member protruding from a lower end of the arc wall toward the inside of the arc wall, When viewed from the axial direction of the bell mouth, the arc wall is formed in a C shape, an opening communicating with the inside and outside of the arc wall is formed between both end portions of the arc wall in the circumferential direction; A vortex suppression member characterized in that, when viewed from the axial direction of the bell mouth, the lower protruding member is formed in a C-shape or a fan-shape and protrudes to an area inside the suction port of the bell mouth.

2. a partition wall is provided in the arc wall to separate the inside of the arc wall; 2. The vortex suppression member according to claim 1, wherein a cylindrical body is formed, the cylindrical body being surrounded by the arc wall and the partition wall and being open both in the upper and lower directions.

3. A bottom plate facing the lower part of the suction port is attached to the partition wall, 3. The vortex suppression member according to claim 2, wherein the bottom plate is disposed on an extension of the axis of the bell mouth.

4. 4. The vortex suppression member according to claim 2 or 3, wherein an upper end of the partition wall is located lower than an upper end of the arc wall.

5. A pump equipped with the vortex suppression member according to any one of claims 1 to 4, A pump characterized in that a vortex suppressing member is attached to a bell mouth.

6. A pump facility provided with the pump according to claim 5 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.

Images