Vortex generation suppression device, pump comprising vortex generation suppression device, and pump installation with pump provided in water suction tank

Abstract

To provide a vortex generation suppression device capable of effectively suppressing generation of an air suction vortex in a water suction tank during pump operation in the water suction tank.SOLUTION: A vortex generation suppression device 10 is provided on a casing 5 of a pump 100 installed in a water suction tank, and comprises a pair of first ridge parts 11 provided on an outer surface of the casing 5 so as to extend in a longitudinal direction of the casing 5. The pair of first ridge parts 11 face each other in a direction intersecting a flow direction of water in the water suction tank from an upstream side toward the casing 5, and are provided on the outer surface of the casing 5 at a narrowed portion where a distance between an outer peripheral surface of the casing 5 and a side wall surface 6 of the water suction tank T is narrowest or at a portion adjacent to the narrowed portion, and each first ridge part 11 has a plurality of recess parts 11b provided at a radial end part of the casing 5 along a longitudinal direction of the first ridge part.SELECTED DRAWING: Figure 1C

Description

[Technical field]

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

[0002] Conventionally, water such as rainwater flows into a suction tank of a pumping facility, is sucked up by a vertical pump, and is sent to a treatment facility downstream of the suction tank. A standard suction tank has a pair of side walls, a rear wall, and a bottom, and the pump is installed in front of the rear wall with its suction port facing downward.

[0003] When the pump is operated, water in the suction tank flows into the pump from the suction port and is sent through the pump to a downstream treatment facility. When the pump is operated, an air-suction vortex V1 and a submerged vortex V2 may be generated in the suction tank T, as shown in Figures 13A and 13B. Figure 13A is a vertical cross-sectional view of a conventional pump 900 and suction tank T. Figure 13B is a horizontal cross-sectional view of the same pump 900 and suction tank T.

[0004] When the water flow F1 from the upstream side of the suction tank T flows around the side surface of the pump 900 toward the rear wall surface 7, if the flow separates from the surface of the pump 900, the flow velocity distribution of the flow becomes uneven, and multiple vortices are generated downstream of the pump 900. The air suction vortex V1 is generated as this vortex grows, and is a vortex flow that flows from the water surface toward the suction port 5c. The air suction vortex V1 entrains air above the water surface and sucks it into the suction port 5c. The submerged vortex V2 is a vortex that is sucked into the suction port 5c when the pressure of the vortex generated from the bottom surface 8 or side wall surface 6 of the suction tank T drops below the steam pressure.

[0005] If the air suction vortex V1 and the submerged vortex V2 are drawn into the pump 900 through the water inlet 5c, there is a risk of violent vibration and loud noise occurring during pump operation. As a vortex suppression device for suppressing the generation of the air suction vortex V1 and the submerged vortex V2, a device as described in Patent Document 1 has been proposed. According to this device, a vortex suppression member is attached to the lower end of the bellmouth of the pump to suppress the generation of vortices. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2023-83628 A Summary of the Invention [Problem to be solved by the invention]

[0007] The vortex suppression device described in Patent Document 1 restricts the water flow from the rear wall surface to the pump's suction port by providing an obstacle at the bottom end of the pump facing the rear wall surface of the suction sump, thereby restricting the water flow from the upstream side to the rear wall surface, thereby preventing the generation of vortexes and the drawing of vortexes into the pump. However, in recent years, pumps have become larger and have larger capacities, and the amount of water drawn into the suction sump has increased, so there is a risk that the vortex suppression device described in Patent Document 1 will not be effective enough in suppressing vortex generation.

[0008] In other words, because the amount of water flowing from the upstream side of the suction tank toward the rear wall surface becomes large, even if the water flow to the suction port is restricted as described above, the water flow around the side of the pump will not be sufficiently controlled, and an air-sucking vortex may occur downstream of the pump.

[0009] If the flow around the sides of the pump is not well controlled and the flow separates from the outside of the pump, a low pressure area is formed near the back of the pump, and the pressure difference between the front and rear of the pump increases. This increases the force that the pump receives from the water flow, and the fluctuation of this force places a load on the pump casing.

[0010] The present invention has been made in consideration of the above problems, and has an object to effectively suppress the occurrence of air-suction vortexes in the suction sump during pump operation in the sump. [Means for solving the problem]

[0011] According to one aspect of the present invention, there is provided a pump installed in a suction tank, comprising: A vortex suppression device provided in a cylindrical casing that stands upright in a tank and is connected to a water intake port facing downward, a pair of first protrusions provided on an outer surface of the casing and extending in a longitudinal direction of the casing; The pair of first protrusions includes They face each other in a direction intersecting the direction of water flow from the upstream side of the suction tank toward the casing (hereinafter, the water flow direction), The nozzle is provided on the outer surface of the casing at a narrowed portion where the gap between the outer peripheral surface of the casing and the side wall surface of the water intake tank is narrowest or at a portion adjacent to the narrowed portion, Each of the first protrusions has a plurality of recesses formed at an end in the radial direction of the casing, the recesses being arranged along the longitudinal direction of the first protrusion.

[0012] According to this, the water flow crossing the first protrusion has a higher flow rate than the water flowing between the outer surface of the casing and the side wall due to the narrowing of the flow path cross-sectional area. In addition, the concave portion of the first protrusion and the convex portion formed by being sandwiched between the adjacent concave portions act as resistance to the water flow crossing the first protrusion. As a result, the flow along the surface of the casing is effectively disturbed and stirred, that is, turbulent. The vortex generation suppression device turbulizes the flow, shifting the separation position where the flow separates from the outer surface of the casing to the downstream side of the pump. Therefore, the generation of vortices due to the effect of flow separation is suppressed downstream of the pump, and as a result, the vortex generation suppression device suppresses the generation of air-suction vortices.

[0013] The vortex suppression device according to the second aspect of the present invention further includes a pair of second protrusions provided on an outer surface of the casing and extending in the longitudinal direction of the casing, The pair of second protrusions face each other in a direction intersecting the water flow direction and are provided downstream of the water flow with respect to the first protrusions, Each of the second protrusions has a plurality of recesses formed at an end in the radial direction of the casing, the recesses being arranged along the longitudinal direction of the second protrusion.

[0014] According to this, the second ridge portion is located downstream of the pump where the separation position has been shifted by the first ridge portion. The second ridge portion re-turbulizes the flow downstream of the pump in the same manner as the first ridge portion. As a result, the vortex suppression device can effectively suppress the generation of air-suction vortexes by shifting the separation position further downstream of the pump.

[0015] The vortex suppression device according to the third aspect of the present invention further includes a pair of third protrusions provided on an outer surface of the casing and extending in the longitudinal direction of the casing, the pair of third protrusions are opposed to each other in a direction intersecting with the water flow direction and are provided upstream of the water flow relative to the first protrusions; Each of the third protrusions has a plurality of recesses formed at an end in the radial direction of the casing, the recesses being arranged along the longitudinal direction of the third protrusion.

[0016] According to this, the third ridge portion promotes turbulence of the flow at the first and second ridge portions by preliminarily disturbing the flow upstream of the first and second ridge portions. As a result, the vortex suppression device can effectively suppress the generation of air-suction vortices by shifting the separation position downstream of the pump.

[0017] The vortex generation suppression device according to the fourth aspect of the present invention further comprises a pair of obstruction portions provided on the outside of the casing and extending along an outer peripheral surface of the casing, The pair of obstruction portions are provided on the outer side of an outer surface of the casing at least downstream from the narrowed portion, and are provided below the first protrusion portion, Each obstacle portion has a flow passage portion that penetrates between the casing and the obstacle portion, and is provided at an incline in the vertical direction with respect to the water flow direction.

[0018] According to this, the water flow crossing the obstacle flows along the underside of the obstacle and is divided into the outside of the obstacle and the flow section inside the obstacle. At that time, the water flow has a larger water flow velocity than the water flow between the outer surface of the casing and the side wall due to the narrowing of the flow path cross-sectional area, and the obstacle acts as a resistance to the flow, effectively turbulentizing the water flow that has passed through the obstacle. As a result, the vortex generation suppression device can effectively suppress the generation of air-suction vortexes by shifting the separation position downstream of the pump.

[0019] A pump according to a fifth aspect of the present invention is a pump including a vortex suppression device provided in a casing, A vortex suppression device is provided on the casing.

[0020] According to this, the pump's vortex suppression device turbulently changes the flow along the surface of the casing, shifting the separation position downstream of the pump. This suppresses the generation of vortices due to the effect of flow separation downstream of the pump, and as a result, the pump suppresses the generation of air-suction vortices.

[0021] A pump facility according to a sixth aspect of the present invention is a pump facility including a pump having a vortex suppression device in a suction tank, The pump is installed in front of the rear wall of the suction tank, A part of the water flow from the upstream side toward the rear wall surface in the suction sump flows to the rear side of the pump through a flow passage formed between the side wall surface of the suction sump and the outer circumferential surface of the pump casing.

[0022] According to this, the pump vortex suppression device installed in the suction tank of the pump equipment turbulently changes the flow along the surface of the casing, shifting the separation position to the downstream side of the pump. This suppresses the generation of vortices due to the effect of flow separation downstream of the pump, and as a result, the pump equipment suppresses the generation of air-suction vortices in the suction tank.

[0023] The pump equipment according to the seventh aspect of the present invention is a pump equipment including a plurality of pumps in a water suction tank, Of the multiple pumps, the pump closest to the side wall of the suction sump has a vortex suppression device.

[0024] According to this, the reverse water flow from the rear wall surface along each side wall surface, across the first protrusions, toward the upstream side of the pump has a higher flow velocity than in other parts of the suction tank, and the concave and convex portions of the first protrusions effectively turbulize the flow, shifting the separation position upstream of the pump. As a result, the pump equipment suppresses the occurrence of air-sucking vortexes in the vicinity of the pump close to each side wall surface. Effect of the Invention

[0025] According to the present invention, it is possible to effectively suppress the occurrence of air-suction vortexes in the suction sump during pump operation in the suction sump. [Brief description of the drawings]

[0026] [Figure 1A] 1 is a vertical sectional view of a pump facility including a vertical pump having a vortex suppression device according to a first embodiment of the present invention. [Figure 1B] FIG. 1B is a cross-sectional view taken along line AA in FIG. 1A. [Figure 1C] FIG. 1B is a longitudinal cross-sectional view taken along line BB in FIG. 1A. [Figure 2A] 1B is an enlarged view of a main portion of FIG. 1A, showing the state of water flow in the vicinity of the vortex generation suppression device; FIG. [Figure 2B] 2B is a cross-sectional view taken along line CC in FIG. 2A, showing the state of water flow in the vicinity of the vortex suppression device. FIG. [Diagram 3] 4 is a cross-sectional view showing the state of water flow around a pump equipped with the vortex suppression device and a conventional pump. FIG. [Figure 4] FIG. 11 is a front view of a pump having a modified example of the vortex suppression device. [Figure 5A] FIG. 5 is a vertical sectional view of a pump facility including a pump having a vortex suppression device according to a second embodiment of the present invention. [Figure 5B] FIG. 5B is a cross-sectional view taken along line DD in FIG. 5A. [Figure 6] 4 is a cross-sectional view showing the state of water flow around a pump equipped with the vortex suppression device and a conventional pump. FIG. [Figure 7A] FIG. 11 is a vertical sectional view of a pump facility including a pump having a vortex suppression device according to a third embodiment of the present invention. [Figure 7B] FIG. 7B is a cross-sectional view taken along line EE of FIG. 7A. [Figure 7C] FIG. 7B is a longitudinal cross-sectional view taken along line FF in FIG. 7A. [Figure 8] FIG. 2 is a perspective view of a pump having the vortex suppression device, as viewed from the downstream side of the water flow and obliquely from above. [Figure 9] FIG. 2 is a perspective view of a pump having the vortex suppression device as viewed obliquely from below. [Figure 10] 4 is a vertical cross-sectional view showing the state of water flow around a pump equipped with the vortex suppression device. FIG. [Figure 11] FIG. 11 is a cross-sectional view taken along line GG in FIG. 10, showing the state of water flow around a pump equipped with the vortex suppression device and a conventional pump. [Figure 12A] FIG. 2 is a cross-sectional view of a pump installation with multiple pumps, showing an operating condition in which all pumps are running. [Figure 12B] FIG. 2 is a cross-sectional view of the pump equipment, showing an operating state in which some pumps are out of operation. [Figure 13A] FIG. 11 is a vertical cross-sectional view showing a conventional pump and water suction tank. [Figure 13B] FIG. 1 is a cross-sectional view showing a conventional pump and a water suction tank. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, a pipe connection device according to an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are given the same reference numerals and the description will not be repeated. In the following description, terms indicating positions or directions such as "upper", "lower", "horizontal" and "vertical" may be used. These terms are used for convenience to facilitate understanding of the embodiment, and are not limited to positions or directions when actually implemented.

[0028] [Vortex suppression device] First embodiment The configuration of a vortex generation suppression device 10 according to a first embodiment of the present invention will be described with reference to Figures 1A, 1B, and 1C. Figure 1A is a vertical cross-sectional view of a pump facility including a vertical pump 100 having a vortex generation suppression device 10 according to the first embodiment of the present invention. Figure 1B is a cross-sectional view taken along line AA in Figure 1A. Figure 1C is a vertical cross-sectional view taken along line BB in Figure 1A.

[0029] 1A, 1B, and 1C, a pump facility 1 includes a suction tank T and a vertical pump 100 provided in the suction tank T and having a vortex suppression device 10.

[0030] The suction tank T has a pair of side walls 6, a rear wall 7, and a bottom surface 8. In the suction tank T, a water flow F1 is generated from the upstream side toward the rear wall 7. Hereinafter, the direction of the water flow F1 from the upstream side toward the rear wall 7 in the suction tank T will be referred to as the water flow direction. The pump 100 is provided in front of the rear wall 7 and sandwiched between the pair of side walls 6. The pump 100 has a cylindrical casing 5 standing upright in the suction tank T and a bell mouth 5b connected to a lower part of the casing 5. The bell mouth 5b has a water intake port 5c facing the bottom surface 8. In this embodiment, the outer diameter of the bell mouth 5b becomes larger relative to the outer diameter of the casing 5 toward the lower part of the bell mouth 5b, but the shape of the bell mouth 5b is not limited to this embodiment.

[0031] Although not shown, pump 100 has a rotatable main shaft inserted into casing 5, an impeller that rotates together with the main shaft, and a rotary drive device that rotates the main shaft.

[0032] Specifically, the vortex suppression device 10 is a pair of long plate-shaped first protrusions 11 provided on the outer surface of the casing 5 of the pump 100, extending in the longitudinal direction (up-down direction) of the casing 5. The pair of first protrusions 11 are provided on the outer surface of the casing 5 facing each other in a direction perpendicular to the water flow direction when viewed from above the pump 100. The pair of first protrusions 11 are arranged along the radial direction of the casing 5, and one end in the width direction is connected to the outer surface of the casing 5.

[0033] The pair of first protrusions 11 are provided on the outer surface of the casing 5 at narrowed portions where the distance between the outer circumferential surface of the casing 5 and each of the side wall surfaces 6, 6 of the water absorption tank T is the narrowest. That is, as shown in Fig. 1A and Fig. 1B, the pair of first protrusions 11 are provided on the outer surface of the casing 5 across the diameter of the casing 5 in a direction perpendicular to the water flow direction.

[0034] The pair of first protrusions 11 have a plurality of recesses 11b and protrusions 11c at ends in the radial direction of the casing 5 along the longitudinal direction of the first protrusions 11. The recesses 11b are formed, for example, by penetrating the first protrusions 11 in a rectangular shape in the thickness direction of the first protrusions 11, and the penetrated portions open in the radial direction of the casing 5. The protrusions 11c are formed as portions of the first protrusions 11 that are not penetrated. The shape of the recesses 11b is not limited to this embodiment, and the first protrusions 11 may be configured to be penetrated in the thickness direction of the first protrusions 11 in a semicircular or triangular shape, for example, and the penetrated portions open in the radial direction of the casing 5.

[0035] The recesses 11b and the protrusions 11c are alternately arranged at a predetermined interval on the first protrusion 11. There is no restriction on the number of recesses 11b and protrusions 11c, but they are appropriately set in consideration of the outer diameter of the casing 5, the axial length, the water depth, the water flow speed, etc.

[0036] Next, the state of the water flow F1 in the vicinity of the vortex generation suppression device 10 will be described with reference to Figures 2A and 2B. Figure 2A is an enlarged view of a main part of Figure 1A, and shows the state of the water flow F1 in the vicinity of the vortex generation suppression device 10. Figure 2B is a cross-sectional view taken along line CC in Figure 2A, and shows the state of the water flow F1 in the vicinity of the vortex generation suppression device 10.

[0037] The first protrusions 11 are portions whose shape does not follow the flow of the water flow F1 and therefore provide resistance to the flow. In particular, corners 11e formed by providing the recesses 11b and the protrusions 11c provide resistance to the flow.

[0038] 2A and 2B, the first protrusion 11 has a plurality of recesses 11b and protrusions 11c, and thus has a plurality of corners 11e formed in the recesses 11b and protrusions 11c along the longitudinal direction of the first protrusion 11. The corners 11e may be formed of an R portion having a certain curvature (this is also true in other embodiments described later).

[0039] As shown in Figures 2A and 2B, the water flow F1 passing through these corners 11e is effectively disturbed and stirred as a result of each corner 11e acting as a resistance to the flow (F11 in the figures).

[0040] Next, the state of the water flow F1 around the pump 100 equipped with the first protrusion portion 11 and the conventional pump 900 will be compared and described with reference to Fig. 3. Fig. 3 is a cross-sectional view showing the state of the water flow F1 around the pump 100 equipped with the vortex suppression device 10 and the conventional pump 900.

[0041] 3 shows the state of the water flow F1 around the conventional pump 900, and the lower diagram of FIG. 3 shows the state of the water flow F1 around the pump 100 equipped with the vortex suppression device 10. As shown in FIG.

[0042] In the upper diagram of Fig. 3, in the case of the conventional pump 900, as described above, the water flow F1 separates from the surface of the pump 900 as it crosses the pump 900, which causes the flow velocity distribution of the flow to become uneven, generating multiple vortices F19 downstream of the pump 900, and these vortices F19 grow to generate air-suction vortices V1. Note that "separation" is a phenomenon in which a fluid is unable to flow along an object due to the influence of the viscosity of the fluid, the shape of the object, etc., and the fluid flow separates from the surface of the object. When a flow separates from an object, a low-pressure area accompanied by a backflow or vortex is formed downstream of the object.

[0043] In a pump 100 equipped with a vortex suppression device 10 shown in the lower diagram of Figure 3, the first protrusion portion 11 is provided on the outer surface of the casing 5 at a portion where the flow path cross-sectional area formed between the outer peripheral surface of the casing 5 and each side wall surface 6, 6 of the suction tank is most narrowed from the upstream side to the downstream side, and as a result, the speed of the water flow F1 crossing the first protrusion portion 11 is greater than the water flow F1 crossing a conventional pump 900.

[0044] Furthermore, before the flow separates and generates a vortex F19 as shown in the upper diagram of Fig. 3, the first protrusions 11 are provided in the flow, and as a result, the water flow F1 crossing the first protrusions 11 has a high flow rate as described above, and the corners 11e (see Figs. 2A and 2B) formed on the recesses 11b and protrusions 11c in particular provide resistance to the flow, effectively disrupting and stirring the flow (F11 in the lower diagram of Fig. 3). In other words, the vortex generation suppression device 10 transitions the water flow F1 from a laminar flow to a turbulent flow.

[0045] Generally, a flow transitions from laminar to turbulent, that is, becomes turbulent, making it difficult for the flow to separate from the surface of an object. Such control of flow separation by turbulence is commonly performed. For example, a golf ball's dimples make the flow on the ball surface turbulent by providing multiple recesses on the ball surface, and shift the separation position where the flow separates from the ball surface downstream of the ball. When a flow separates from the surface of an object, a low-pressure area is formed on the rear back surface of the object, and the pressure difference between the front and back surfaces of the object becomes resistance in the flow of the object. In other words, by shifting the separation position downstream using dimples, the golf ball can reduce resistance in the flow.

[0046] The vortex generation suppression device 10 also applies turbulence to control flow separation as described above, and by turbulising the flow along the surface of the casing 5, the separation position is shifted downstream of the pump 100. This suppresses the generation of vortices due to the effect of flow separation downstream of the pump 100 (F16 in the figure), and as a result, the vortex generation suppression device 10 suppresses the generation of an air-suction vortex V1.

[0047] In addition, by shifting the separation position downstream of the pump 100, the low pressure area generated on the back surface of the pump 100 is reduced, and the pressure difference between the front surface and the back surface of the pump 100 is reduced, thereby reducing the force that the pump 100 receives from the water flow F1. As a result, the vortex suppression device 10 can reduce the load on the casing 5 of the pump 100.

[0048] The vortex suppression device 10 does not necessarily have to have a pair of first protrusions 11, and may be configured so as to be arranged on only one side of the pump 100 when viewed from the water flow direction. Also, in this embodiment, the recessed portion 11b and the protruding portion 11c are provided only in a portion of the casing 5 where the outer diameter is constant, but they may be provided extending in the longitudinal direction up to the lower end of the bellmouth 5b at the bottom of the casing 5.

[0049] Furthermore, in this embodiment, the outer diameter of the casing 5 excluding the bell mouth 5b is constant, but as shown in FIG. 4, the outer diameter of the casing 105 excluding the bell mouth 5b may be configured to change depending on the axial position of the pump 100d. FIG. 4 is a front view of a pump 100d having a modified example 10d of the vortex generation suppression device 10. In this case, the first protrusions 11 are configured of first protrusions 11, 11 having the same widthwise length regardless of the change in the outer diameter of the casing 105 in which the first protrusions 11 are provided, so that the widths D1, D2 between the ends in the radial direction of the casing 105 may be configured to vary with the change in the outer diameter of the casing 105. By using the same first protrusions 11 even if the outer diameter of the casing 105 is different, the vortex generation suppression device 10d can effectively suppress the generation of air suction vortices while having the cost advantage of sharing members.

[0050] Second embodiment Next, a vortex generation suppression device 20 according to a second embodiment of the present invention will be described with reference to Figures 5A and 5B. Figure 5A is a vertical cross-sectional view of a pump facility 2 including a pump 200 having a vortex generation suppression device 20 according to the second embodiment of the present invention. Figure 5B is a horizontal cross-sectional view taken along line DD in Figure 5A.

[0051] As shown in Figures 5A and 5B, the vortex generation suppression device 20, in addition to the first protrusion portion 11, further includes a pair of long plate-shaped second protrusion portions 12 and a pair of third protrusion portions 13 that are provided on the outer surface of the casing 5 and extend in the longitudinal direction of the casing 5.

[0052] The pair of second protrusions 12 face each other in a direction perpendicular to the water flow direction, and are provided downstream of the water flow F1 from the pair of first protrusions 11. The pair of third protrusions 13 face each other in a direction intersecting the water flow direction, and are provided upstream of the water flow F1 from the pair of first protrusions 11.

[0053] Similar to the first ridge portions 11, the pair of second ridge portions 12 and the pair of third ridge portions 13 are disposed along the radial direction of the casing 5, and one end in the width direction is connected to the casing 5. That is, the first ridge portions 11, the second ridge portions 12, and the third ridge portions 13 are provided radially on the outer surface of the casing 5, as shown in Fig. 5B.

[0054] In this embodiment, the pair of second ridges 12 are provided on the outer surface of the casing 5 at positions obtained by rotating each of the first ridges 11 in the water flow direction around the pump axis z from the position where the first ridges 11 are provided, as viewed from above the pump 200. Similarly, the pair of third ridges 13 are provided on the outer surface of the casing 5 at positions obtained by rotating each of the first ridges 11 in the opposite direction to the water flow direction, a predetermined angle, for example, 45°, from the position where the first ridges 11 are provided. However, the second ridges 12 and the third ridges 13 may be configured so that the predetermined angle is an angle other than 45°, for example, 20°, 30°, etc., depending on the conditions of the water flow F1, etc.

[0055] Similarly to the first protrusion 11, the second protrusion 12 and the third protrusion 13 are provided with a plurality of recesses 12b, 13b and protrusions 12c, 13c at the radial end of the casing 5 along the longitudinal direction of the second protrusion 12 and the third protrusion 13. That is, similar to the first protrusion 11, the second protrusion 12 and the third protrusion 13 have a plurality of corners (reference numbers omitted) formed by the recesses 12b, 13b and the protrusions 12c, 13c. In this embodiment, the first protrusion 11, the second protrusion 12 and the third protrusion 13 are formed using the same material. That is, the arrangement of the recesses 12b, 13b and the protrusions 12c, 13c in the second protrusion 12 and the third protrusion 13 is the same as the arrangement of the recesses 11b and the protrusions 11c in the first protrusion 11.

[0056] Next, the state of the water flow F1 around the pump 200 equipped with the vortex generation suppression device 20 and the conventional pump 900 will be compared and explained with reference to Fig. 6. Fig. 6 is a cross-sectional view showing the state of the water flow F1 around the pump 200 equipped with the vortex generation suppression device 20 and the conventional pump 900. The upper diagram of Fig. 6 shows the state of the water flow F1 around the conventional pump 900, and the lower diagram of Fig. 6 shows the state of the water flow F1 around the pump 200 equipped with the vortex generation suppression device 20.

[0057] As can be seen from the upper diagram of Figure 6, in the conventional pump 900, an air-suction vortex V1 occurs downstream of the pump 900, as described above. In contrast, in the case of a pump 200 equipped with a vortex generation suppression device 20 shown in the lower diagram of Figure 6, the water flow F1 passing through the first protrusion 11 is disturbed and agitated, as described above (F11 in the diagram).

[0058] The second protrusion 12 is provided at the above-mentioned position, and is therefore located downstream of the pump 200 where the separation position has been shifted by the first protrusion 11. Like the first protrusion 11, the second protrusion 12, particularly the corners (reference numerals omitted) of the second protrusion 12, create flow resistance downstream of the pump 200 where the separation position has been shifted, effectively disrupting the flow and making it turbulent again (F12 in the figure). As a result, the vortex generation suppression device 20 can effectively suppress the generation of the air suction vortex V1 by further shifting the separation position downstream of the pump 200 (F17 in the figure).

[0059] Similar to the first ridge portions 11 and the second ridge portions 12, the third ridge portions 13 also effectively disrupt the flow (F13 in the figure) by providing resistance to the flow, particularly at corners (reference numbers omitted) of the third ridge portions 13. The third ridge portions 13 are provided upstream of the first ridge portions 11 and the second ridge portions 12, thereby disrupting and stirring the flow before the water flow F1 passes through the first ridge portions 11 and the second ridge portions 12.

[0060] In other words, the third ridge 13 disturbs the flow in advance upstream of the first ridge 11 and the second ridge 12, thereby promoting the turbulence of the flow in the first ridge 11 and the second ridge 12 located downstream. As a result, the vortex suppression device 20 can effectively suppress the generation of the air-suction vortex V1 by shifting the separation position further downstream of the pump 200 (F17 in the figure).

[0061] As described above, by shifting the separation position downstream of the pump 200, the low-pressure area generated at the rear surface of the pump 200 is reduced, and the pressure difference between the front and rear surfaces of the pump 200 is reduced, thereby reducing the force that the pump 200 receives from the water flow F1. As a result, the vortex suppression device 20 can reduce the load on the casing 5 of the pump 200.

[0062] In addition, since the second ridge portion 12 and the third ridge portion 13 are arranged downstream and upstream of the first ridge portion 11, respectively, the flow path cross-sectional area in the portion where they are arranged is larger than the flow path cross-sectional area in the portion where the first ridge portion 11 is arranged. As a result, the speed of the water flow F1 near the second ridge portion 12 and the third ridge portion 13 is smaller than the flow of the water flow F1 near the first ridge portion 11. Therefore, the effect of the second ridge portion 12 and the third ridge portion 13 in disturbing the flow is smaller than that of the first ridge portion 11. In other words, the second ridge portion 12 and the third ridge portion 13 auxiliary disturb the water flow F1 passing through the first ridge portion 11.

[0063] As described above, the vortex generation suppression device 20, which further includes the second ridge portions 12 and the third ridge portions 13, is more effective at disrupting the water flow F1 than the vortex generation suppression device 10 which includes only the first ridge portions 11. As a result, the vortex generation suppression device 20 can effectively suppress the generation of air suction vortex V1 downstream of the pump 200.

[0064] In this embodiment, the vortex generation suppression device 20 is configured to have both the second ridge portions 12 and the third ridge portions 13, but the vortex generation suppression device 20 may be configured to have only one of the second ridge portions 12 and the third ridge portions 13. Similarly to the first ridge portions 11 of the vortex generation suppression device 10, the vortex generation suppression device 20 may be configured so that the second ridge portions 12 and the third ridge portions 13 are not arranged in pairs, but are arranged only on one side of the pump 200 when viewed from the water flow direction.

[0065] Third embodiment Next, a vortex generation suppression device 30 according to a third embodiment of the present invention will be described with reference to Figs. 7A to 7C, 8 and 9. Fig. 7A is a vertical cross-sectional view of a pump facility 3 including a pump 300 having a vortex generation suppression device 30 according to a third embodiment of the present invention. Fig. 7B is a horizontal cross-sectional view taken along line EE in Fig. 7A. Fig. 7C is a vertical cross-sectional view taken along line FF in Fig. 7A. Fig. 8 is a perspective view of the pump 300 as viewed from the downstream side of the water flow and obliquely from above. Fig. 9 is a perspective view of the pump 300 as viewed from below.

[0066] 7A to 7C, 8 and 9, the vortex generation suppression device 30 further includes, in addition to the vortex generation suppression device 20 according to the second embodiment, an annular flange 5d arranged above the bellmouth 305b on the outer surface of the casing 305, a pair of first obstacles 14 provided below the flange 5d and outside the bellmouth 305b, and a second obstacle 17 provided below the water intake 5c. In this embodiment, the outer diameter and inner diameter of the bellmouth 305b are once smaller than the outer diameter of the casing 305 downward from the connection part with the flange 5d, and then become larger toward the water intake 5c after passing the "throat" where the outer diameter is smallest. However, the form of the bellmouth 305b is not limited to this embodiment, and may be configured using the bellmouth 5b according to the first or second embodiment, for example.

[0067] The pair of first obstacle portions 14 are plate-like bodies whose longitudinal direction extends along the outer peripheral surface of the casing 305 when viewed from above the pump 300, and are provided on the outside of the outer surface of the casing 305 at least downstream from the narrowed portion.

[0068] In detail, the pair of first obstacle parts 14 are connected to the lower surface of the flange 5d at their upstream end in the longitudinal direction, facing each other in a direction perpendicular to the water flow direction in a top view of the pump 300. The pair of first obstacle parts 14 are connected to the outer surface of the bell mouth 305b at a position rotated in the water flow direction by a predetermined angle, for example, 45°, from the position where each end is disposed about the pump axis z in a top view of the pump 300. At that time, each first obstacle part 14 is connected to the lower surface of the flange 5d and the outer surface of the bell mouth 305b so as to have a flow part 15 penetrating between the bell mouth 305b and each first obstacle part 14.

[0069] As described above, the pair of first obstacle portions 14 have one and the other longitudinal ends connected to the underside of the flange 5d and the outer surface of the bell mouth 305b, and are configured so that, as shown in FIG. 7A, the approximate inclination angle θ with respect to the horizontal plane in a side view of the pump 300 is inclined downward at a predetermined inclination angle, for example, 45°.

[0070] 7A, in particular, in the lower part of the pump 300, in addition to the water flow F1 flowing from the upstream side of the suction tank T toward the rear wall surface 7, there is a water flow F2 flowing from above the pump 300 downward toward the suction port 5c. These water flows F1 and F2 join together to form a water flow F3 (hereinafter referred to as the oblique water flow F3) flowing diagonally downward to the right in FIG. 7A. The oblique water flow F3, like the water flow F1, also causes the generation of an air-sucking vortex.

[0071] The applicants have experimentally confirmed that the oblique water flow F3 is a flow that is inclined downward at approximately 45° with respect to the water flow direction. Therefore, by providing the pair of first obstacle portions 14 on the outside of the bellmouth 305b of the casing 305 as described above, the oblique water flow F3 can flow along the lower surface of the first obstacle portion 14. As shown in FIG. 8 in particular, the oblique water flow F3 flows along the lower surface of the first obstacle portion 14 and is diverted toward the outside of the first obstacle portion 14 and the flow portion 15 on the inside of the first obstacle portion 14.

[0072] As shown particularly in Figures 7C and 9, the second obstacle section 17 has a cylindrical member 18 whose axial direction extends toward the pump axis, four obstacle plates 19 provided on the outer surface of the cylindrical member 18 and whose upper ends are provided on the inner surface of the bellmouth 305b, and a bearing section 18b provided on the inside of the cylindrical member 18.

[0073] In a top view of the pump 300, the four obstacle plates 19 have their inner ends connected to the outer surface of the cylindrical member 18, extend in a cross shape in the radial direction of the cylindrical member 18, and have their upper ends connected to the inner surface of the bell mouth 305b. At this time, the upper ends of the obstacle plates 19 extend and are connected to the vicinity of the throat portion 5e of the bell mouth 305b. The bearing portion 18b is typically a bearing, and is provided inside the upper portion of the cylindrical member 18 to rotatably support the lower end of the main shaft S of the pump 300.

[0074] Next, the state of the water flow F3 around the vortex generation suppression device 30 will be described with reference to Figures 10 and 11. Figure 10 is a vertical cross-sectional view showing the state of the water flow F3 around the pump 300 equipped with the vortex generation suppression device 30. Figure 11 is a horizontal cross-sectional view taken along line GG in Figure 10, showing a comparison of the state of the water flow F3 around the pump 300 equipped with the vortex generation suppression device 30 and the conventional pump 900. The upper diagram in Figure 11 shows the state of the water flow F3 around the conventional pump 900, and the lower diagram in Figure 11 shows the state of the water flow F3 around the pump 300 equipped with the vortex generation suppression device 30.

[0075] 10 and 11, the oblique water flow F3 flows along the lower surface of the first obstacle portion 14 and branches off toward the outside of the first obstacle portion 14 and the flow section 15 inside the first obstacle portion 14. At that time, the corners 14e formed in the first obstacle portion 14, in particular the corners 14e, act as resistance to the flow, and the oblique water flow F3 is effectively disturbed and agitated downstream of the first obstacle portion 14 (F14, F15 in the figures).

[0076] 11, in the conventional pump 900, as described above, an air-suction vortex V1 is generated downstream of the pump 900. In contrast, in the case of a pump 300 equipped with a vortex generation suppression device 30 shown in the lower diagram of Fig. 11, the first obstacle portion 14 is provided in the flow path of the oblique water flow F3, so that the flow path cross-sectional area formed between the outer surface of the bellmouth 305b and each of the side wall surfaces 6, 6 is narrowed from the upstream side to the downstream side, and the speed of the water flow F3 crossing the first obstacle portion 14 is greater than that of the water flow F3 crossing the conventional pump 900.

[0077] 11, before the flow separates and a vortex F19 is generated, the first obstacle 14 is provided in the flow, so that the water flow F3 crossing the first obstacle 14 is diverted toward the outside of the first obstacle 14 and the circulating portion 15 as described above, and coupled with the fact that the flow velocity is high, the corner 11e in particular acts as a resistance to the flow, effectively disturbing and stirring the flow (F14, F15 in the figure). As a result, the vortex generation suppression device 30 effectively turbulently converts the oblique water flow F3 to a turbulent flow and shifts the separation position downstream of the pump 300, and as a result, the generation of the air suction vortex V1 can be effectively suppressed (F18 in the figure).

[0078] Although not shown, the second obstacle portion 17 is provided in the middle of the flow path of the water flowing into the intake port 5c, and the obstacle plate 19 acts as a resistance to the water flow, weakening the force of the water flow. As a result, the second obstacle portion 17 suppresses the generation of underwater vortexes, particularly in the lower part of the pump 300. At that time, the inner end of the obstacle plate 19 is connected to the outer surface of the cylindrical member 18, so that the stress concentration at the connection part can be reduced more than if the inner ends of the obstacle plates 19 were connected to each other. In addition, the upper end of the obstacle plate 19 extends to the vicinity of the throat portion 5e of the bell mouth 305b and has a sufficient connection length, so that the stress applied to the connection part can be reduced. As a result, the second obstacle portion 17 can effectively suppress the generation of underwater vortexes while maintaining sufficient mechanical strength.

[0079] In addition, the vortex generation suppression device 30 may be configured to further include a flange 5d, a pair of first obstacle portions 14, and a second obstacle portion 17 in addition to the vortex generation suppression device 10 of the first embodiment described above.

[0080] As described above, the vortex generation suppression device 30 effectively disturbs and agitates the water flow F1 in the upper part of the suction tank T mainly by the first ridge portion 11, the second ridge portion 12, and the third ridge portion 13, and effectively disturbs and agitates the water flow F3 in the lower part of the suction tank T by the first obstacle portion 14, thereby effectively suppressing the generation of the air-sucking vortex V1. Furthermore, the vortex generation suppression device 30 weakens the water flow sucked into the suction port 5c by the second obstacle portion 17, thereby effectively suppressing the generation of the underwater vortex V2.

[0081] [Pumping equipment with multiple pumps] Next, pump equipment 4 equipped with a plurality of pumps 401-404 in a suction tank will be described with reference to Fig. 12A and Fig. 12B. Fig. 12A is a cross-sectional view of pump equipment 4 equipped with a plurality of pumps 401-404, illustrating an operating state in which all of pumps 401-404 are in operation. Fig. 12B is a cross-sectional view of pump equipment 4, illustrating an operating state in which some of pumps 401 are out of operation.

[0082] 12A and 12B, the pump equipment 4 has a suction tank T and a plurality of pumps 401-404 arranged side by side in front of a rear wall surface 7 of the suction tank T. In this embodiment, the plurality of pumps 401-404 is configured with four pumps, but the plurality of pumps may be configured with a number other than four. Of the plurality of pumps 401-404, the two pumps 401, 404 close to a pair of side wall surfaces 6, 6 are pumps 200 equipped with the vortex suppression device 20 according to the second embodiment.

[0083] The pump facility 1 is configured to be capable of selectively operating each of the multiple pumps 401-404 to operate or stop the operation depending on the situation at the water intake site. As an example of the operating situation, Fig. 12A shows an operating situation in which all the pumps 401-404 are operating, and Fig. 12B shows an operating situation in which the pump 401 located at the left end of the water intake tank T among the multiple pumps 401-404 is in an operation stopped state, and the other pumps 402-403 are operating.

[0084] When the operating conditions of the multiple pumps 401-404 in the pump equipment 4 differ, the amount of water sucked by the pump equipment 4 as a whole differs, and therefore the velocity distribution of the water flow from the upstream side of the suction tank T toward the rear wall surface 7 differs. Specifically, in the operating condition shown in Fig. 12A in which all the pumps 401-404 are operating, the flow velocity of the water flow F6 is small near each side wall surface 6 due to friction with each side wall surface 6, and the flow velocity increases as the water moves away from each side wall surface 6, reaching a maximum near the center of the width of the suction tank T. In other words, the velocity of the water flow F6 is distributed almost symmetrically in the left-right direction of the suction tank T.

[0085] At this time, the water flow F6 from the upstream side of the suction tank T collides with the rear wall surface 7, and then a part of it branches off to the left and right to become water flows F61 flowing toward each side wall surface 6. Then, the water flow F61 flowing toward each side wall surface 6 collides with each side wall surface 6 and then turns around to the upstream side of the suction tank T. That is, in the pump equipment 4 having the multiple pumps 401-404, since the flow of the water flow F6 toward the rear wall surface 7 is large, a backflow F62 is generated that turns around from the rear wall surface 7 to the upstream side of the suction tank T. This backflow F62 generates an air-suction vortex V1 upstream of the pumps 401 and 404 close to each side wall surface 6.

[0086] The pumps 401, 404 close to each side wall surface 6 are equipped with the vortex generation suppression device 20 according to the second embodiment in this embodiment, but may be configured to be equipped with the vortex generation suppression device 10 according to the first embodiment or the vortex generation suppression device 30 according to the third embodiment.

[0087] As described above, the first protrusions 11 face each other in a direction intersecting the water flow direction from the upstream side toward the casing 5 inside the suction tank T, and are provided at a narrowed portion on the outer surface of the casing 5 where the distance between the outer circumferential surface of the casing 5 and the side wall surface 6 of the suction tank T is the narrowest. By providing the first protrusions 11 in this way, the first protrusions 11 in each of the pumps 401, 404 face each other in a direction intersecting the direction of the backflow F62 flowing from the rear wall surface 7 to the upstream side of the pumps 401, 404, and are provided at a narrowed portion on the outer surface of the casing 5 where the distance between the outer circumferential surface of the casing 5 and the adjacent side wall surface 6 is the narrowest.

[0088] As a result, the flow velocity of the backflow F62 passing through the first protrusions 11 close to each side wall surface 6 increases within the flow of the backflow F62, and the flow is effectively disturbed and stirred by the corners 11e (see FIGS. 2A and 2B) of the first protrusions 11. As a result, the pump equipment 4 suppresses the generation of air-suction vortexes V1 upstream of the pumps 401, 404 close to each side wall surface 6 by shifting the separation position of the first protrusions 11 to the upstream side of the pumps 401, 404.

[0089] 12B, in an operating state in which pump 401 at the left end of suction tank T is stopped, no suction flow is generated by pump 401. As a result, the flow velocity of water flow F7 from the upstream side of suction tank T is reduced near each side wall surface 6 due to friction with each side wall surface 6 as described above, and the flow velocity near the left side wall surface 6 is minimized because pump 401 facing the left side wall surface 6 is stopped. The flow velocity of water flow F7 increases with increasing distance from each side wall surface 6, and the flow velocity is maximized on the right side of suction tank T rather than the center because pumps 402 to 404 on the right side of suction tank T are operating.

[0090] 12A, the water flow F7 from the upstream side of the suction tank T collides with the rear wall surface 7, and therefore a part of the water flow F7 branches to the left and right to become water flows F71 toward each side wall surface 6. Here, since no suction flow is generated around the pump 401 that is not in operation, the vicinity of the pump 401 becomes a water stop area SA. As a result, a part of the water flow F71 that has flowed around behind the pump 402 becomes a water flow F73 that passes between the pumps 401 and 402 and flows toward the upstream side of the pump 402, instead of flowing toward the left side wall surface 6. This water flow F73 generates an air suction vortex V11 upstream of the pump 402.

[0091] In order to effectively suppress the generation of this air suction vortex V11, it is necessary to effectively disturb the water flow F73 that affects the generation of the air suction vortex V11. To achieve this, a vortex generation suppression device that is provided in accordance with the flow of the water flow F73 is required. In other words, in order to effectively suppress the generation of the air suction vortex V11, a vortex generation suppression device other than the vortex generation suppression device 20 that is provided in accordance with the flow of the water flow F7 from the upstream side is required.

[0092] On the other hand, in the vicinity of the pump 404 close to the right side wall surface 6, a reverse water flow F72 is generated that flows from the rear wall surface 7 along the side wall surface 6 to the upstream side of the pump 404, as in the case shown in Fig. 12A. As a result, an air-suction vortex V1 is generated upstream of the pump 404. The vortex suppression device 20 provided in the pump 404 effectively suppresses the generation of this air-suction vortex V1 as described above.

[0093] In other words, when a plurality of pumps 401-404 are arranged in the suction tank T, the velocity distribution of the water flow in the suction tank T changes each time depending on the operating conditions of the pumps, making it difficult to effectively suppress the air suction vortex V1 generated near the pumps 402, 403 inside the suction tank T. Meanwhile, in the vicinity of each side wall surface 6, the flow along the side wall surface 6 becomes the mainstream. By providing the vortex generation suppression device 20 according to the present invention to the pumps 401, 404 close to each side wall surface 6, the pump equipment 4 can effectively suppress the generation of the air suction vortex V1 upstream of the pumps 401, 404 close to the side wall surface 6. Therefore, even when the operating conditions of each of the plurality of pumps 401-404 are different, the pump equipment 4 can effectively suppress the generation of the air suction vortex V1 at least near the pumps 401, 404 close to each side wall surface 6.

[0094] The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to the above embodiments, and can be implemented in various forms without departing from the spirit of the present invention. The drawings are mainly schematic illustrations of each component for ease of understanding, and the thickness, length, number, spacing, etc. of each component shown in the drawings are different from the actual ones due to the convenience of drawing. In addition, the material, shape, dimensions, etc. of each component shown in the above embodiments are merely examples and are not particularly limited, and various modifications are possible within a range that does not substantially deviate from the configuration of the present invention. [Explanation of symbols]

[0095] T water absorption tank F1 water flow 1. Pump equipment 5 Casing 5b Bellmouth 5c Water intake 5d flange 6 Side wall 7 Rear wall 8 Bottom 10. Vortex suppression device 11 First protrusion 11b Recess 11c Convex part 11e Corner 12 Second protrusion 13 Third protrusion 14 First Obstacle Section 15 Distribution Department 17 2nd Obstacle Section 100 Pump 900 Conventional pump V1 Air-suction vortex V2 Underwater Vortex

Claims

1. In a pump installed in a suction tank, A vortex suppression device provided in a cylindrical casing that stands upright in a tank and is connected to a water intake port facing downward, a pair of first protrusions provided on an outer surface of the casing and extending in a longitudinal direction of the casing; The pair of first protrusions includes They face each other in a direction intersecting the direction of water flow from the upstream side of the suction tank toward the casing (hereinafter, water flow direction), The nozzle is provided on the outer surface of the casing at a narrowed portion where the gap between the outer peripheral surface of the casing and the side wall surface of the water intake tank is narrowest or at a portion adjacent to the narrowed portion, Each of the first protrusions has a plurality of recesses formed at a radial end of the casing along the longitudinal direction of the first protrusion. A vortex generation suppression device characterized by:

2. A pair of second protrusions are provided on the outer surface of the casing and extend in the longitudinal direction of the casing, the pair of second protrusions are opposed to each other in a direction intersecting with the water flow direction and are provided downstream of the water flow with respect to the first protrusions, Each of the second protrusions has a plurality of recesses formed at a radial end of the casing along the longitudinal direction of the second protrusion.

2. The vortex suppression device according to claim 1.

3. a pair of third protrusions provided on an outer surface of the casing and extending in the longitudinal direction of the casing; the pair of third protrusions are opposed to each other in a direction intersecting with the water flow direction and are provided upstream of the water flow relative to the first protrusions, Each of the third protrusions has a plurality of recesses formed at a radial end of the casing along the longitudinal direction of the third protrusion.

3. The vortex suppression device according to claim 2.

4. The housing further includes a pair of obstacles disposed on the outside of the housing and extending along an outer peripheral surface of the housing; The pair of obstruction portions are provided on the outer side of an outer surface of the casing at least downstream from the narrowed portion, and are provided below the first protrusion portion, Each obstacle has a flow passage that penetrates between the casing and the obstacle, and is provided at an incline in the vertical direction with respect to the water flow direction. The vortex suppression device according to any one of claims 1 to 3.

5. A pump equipped with the vortex generation suppression device according to any one of claims 1 to 3, A vortex suppression device is provided on the casing. A pump characterized by:

6. A pump facility including the pump according to claim 5 in a water suction tank, The pump is installed in front of the rear wall of the suction tank, A part of the water flow from the upstream side toward the rear wall surface in the suction tank flows to the rear side of the pump through a flow passage formed between the side wall surface of the suction tank and the outer circumferential surface of the pump casing. A pump installation comprising:

7. A pump facility having a plurality of pumps in a suction tank, Among the plurality of pumps, a pump close to a side wall of the suction tank is a pump equipped with the vortex suppression device according to any one of claims 1 to 3. A pump installation comprising:

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