JP2010249120A - Vortex prevention device and pump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vortex prevention device of a simple structure which can be easily attached to an existing pump device without deteriorating drain performances of a pump. <P>SOLUTION: The vortex prevention device 35 is attached to a suction pipe of the pump 10. The vortex prevention device 35 includes a plate shape horizontal overhang member 35a disposed at a radial direction outside of a suction port 11a of the suction pipe 11 and extending roughly horizontally. The horizontal overhang member 35a is disposed at a downstream side of the suction pipe 11 with respect to a flow direction of liquid. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a vortex prevention device used for a pump device that pumps water in a suction water tank connected to a river or the like, and a pump device including the vortex prevention device.

  At the suction port of the horizontal and vertical shaft pumps, a vortex may be generated on the free surface of the suction water tank as the water level decreases (the water surface becomes closer to the suction port). When the vortex is drawn into the pump, it becomes an air suction vortex and air enters the pump. As a result, abnormalities such as water drop and vibration are caused, and the pump is broken. Therefore, to prevent air from being sucked in, lower the bottom level of the suction tank, lower the position of the suction port of the pump, limit the water absorption level, and do not operate the pump below that level. Has traditionally been done. It has also been proposed to provide a vortex prevention device that covers the free surface of the suction water tank so as to prevent the generation of vortices (see Non-Patent Document 1, for example).

  As other vortex prevention measures, the suction bell mouth has a double structure (see Patent Document 1), a cylindrical member formed with a large number of holes is arranged around the pump suction pipe (see Patent Document 2), Various attempts have been made such as connecting a suction cylinder that opens horizontally to a suction port of a pump (see Patent Document 3).

  However, in the method of lowering the bottom level of the suction water tank, civil engineering costs and construction costs are expensive. In addition, when the existing pump station was refurbished, the construction period was longer, and it was practically impossible to perform rehabilitation work including civil works while operating the pump station.

  In the method of covering the surface of the suction water tank, a plate-like vortex preventing member for covering the water surface is necessary, and costs are increased. Furthermore, it is necessary to fasten the vortex preventing member to a suction water tank that is a civil engineering enclosure, which may cause a problem in civil engineering strength. In addition, there is a problem that dust flowing into the suction water tank gets entangled with the vortex prevention member, and that dust deposited on the bottom surface of the suction water tank is difficult to clean.

  Patent Documents 1 and 2 have a structure in which water flows into a small gap or hole. For this reason, debris such as branches, grass, cloth, etc. contained in river water or sewage, which is handled water in a normal pump station, gets entangled in the gaps and holes and closes these gaps or holes. If the gap or hole is blocked, the function of preventing vortices cannot be secured, and in the worst case, the suction function of the pump is also affected. As a result, satisfactory pump operation cannot be performed (rated drainage operation cannot be performed), which may cause inundation damage.

  In patent document 3, since it is the structure which covers a suction inlet with a cylinder, the suction head loss of a pump becomes large. That is, there is a problem that piping loss or efficiency reduction is caused and the drainage performance of the pump is lowered.

  In addition, it may be required to pump water at a low water level in the operation of the pump station. In this case, the suction port is lowered as much as possible to increase the distance between the water surface and the suction port (that is, the submerged depth of the suction port) so that the air suction vortex does not occur. However, when the suction port approaches the bottom plate of the suction water tank, there is a problem that an underwater vortex from the bottom plate or the side wall of the suction water tank is likely to be generated.

  In Non-Patent Document 1 and Patent Document 4, it is proposed to provide a structure such as a column or a block body on the bottom of the suction water tank in order to prevent such an underwater vortex. However, if the structure as described above is installed in the suction tank, which is a civil engineering enclosure, not only will the cost increase, but it will also be necessary to fasten it to the suction tank, resulting in problems in strength and construction conditions (costs and construction period). May occur. Furthermore, when handling poor quality water, sludge may accumulate on the bottom of the suction tank. As a result, there is a problem that the vortex prevention element installed on the bottom plate is buried and the vortex prevention function is not exhibited.

JP 2002-155898 A JP 2001-41200 A JP 2000-97199 A JP 03-156200 A

Published by the Japan Society of Mechanical Engineers, Japan Society of Mechanical Engineers Standards “Model Test Method for Pump Suction Water Tank”

  The present invention has been made in view of the above-described conventional problems, and is a vortex prevention device that has a simple structure, does not deteriorate the drainage performance of the pump, and can be easily attached to an existing pump device. The purpose is to provide. Moreover, an object of this invention is to provide the pump apparatus provided with this vortex prevention apparatus.

In order to solve the above-described problem, one aspect of the present invention is a vortex prevention device attached to a suction pipe of a pump, and is arranged on the radially outer side of the suction port of the suction pipe, and has a plate shape extending substantially horizontally. The horizontal overhang member is provided.
In a preferred aspect of the present invention, the horizontal projecting member is arranged on the downstream side of the suction pipe with respect to the flow direction of the liquid.
In a preferred aspect of the present invention, a plate-like vertical projecting member extending upward from an outer edge of the horizontal projecting member is further provided.
In a preferred aspect of the present invention, the vortex prevention device is composed of a plurality of segments that are equally divided in the circumferential direction of the suction port.

  Another aspect of the present invention is a pump device that pumps up liquid in a suction water tank, the pump having a suction pipe disposed in the suction water tank, a drive source that drives the pump, and an attachment to the suction pipe The vortex prevention device includes a plate-like horizontal projecting member that is disposed radially outside the suction port of the suction pipe and extends substantially horizontally.

  Another aspect of the present invention is a vortex prevention device that is attached to a suction pipe of a pump, and includes a suction plate that projects downward from a suction port of the suction pipe.

In a preferred aspect of the present invention, the suction plate is larger than the diameter of the suction port.
In a preferred aspect of the present invention, the suction plate is connected to the suction port via a spacer, and the suction plate is separated from the suction port.
The preferable aspect of this invention is further equipped with the at least 1 fin arrange | positioned at the radial direction outer side of the said suction inlet, and the said fin is arrange | positioned substantially perpendicularly with respect to the flow direction of the liquid which flows through the inside of a suction water tank. Features.

Another aspect of the present invention is a vortex prevention device attached to a suction pipe of a pump, comprising at least one fin disposed radially outside a suction port of the suction pipe, wherein the fin is in a suction water tank. It is characterized by being arranged substantially perpendicularly to the flow direction of the liquid flowing through.
Another aspect of the present invention is a vortex prevention device attached to a suction pipe of a pump, comprising a partition plate that is disposed in the suction pipe and divides a flow path in the suction pipe into a plurality of flow paths. The plate is disposed substantially parallel to the suction pipe.

  According to the present invention, the vortex preventing device is provided compactly adjacent to the suction port of the pump, and there is almost no fluid (water head) loss. Occurrence can be prevented. In addition, since the vortex prevention device is installed in the suction pipe of the pump, it is not necessary to fasten the suction water tank and the reinforcement work of the suction water tank is unnecessary. Further, the vortex prevention device can be easily attached to and replaced with the pump, and it is not necessary to stop the operation of the pump device for a long period of time for the vortex prevention device to be attached or exchanged. Moreover, since generation | occurrence | production of an underwater vortex can be prevented, a suction position can be lowered | hung and a pump driving | operation at a low water level is attained.

It is a schematic diagram which shows the pump apparatus provided with the vortex prevention apparatus which concerns on the 1st Embodiment of this invention. It is the sectional view on the AA line of FIG. FIG. 3A is an enlarged view showing an example of the joint portion of the lower end portion of the suction pipe and the vortex prevention device, and FIG. 3B is another example of the joint portion of the lower end portion of the suction pipe and the vortex prevention device. It is an enlarged view shown. It is a figure which shows the example of the vortex prevention apparatus formed so that the perimeter of a suction inlet might be enclosed. It is a figure which shows the example of the vortex prevention apparatus formed so that the semicircle of a suction inlet might be enclosed. It is a figure which shows the Karman vortex which generate | occur | produces in the downstream of a suction pipe. It is a figure for demonstrating a mode that formation of an air suction vortex is prevented by a vortex prevention device. FIG. 8A is a plan view showing a vortex preventing device according to the second embodiment of the present invention, and FIG. 8B is a longitudinal sectional view of the vortex preventing device shown in FIG. 8A. . It is a figure which shows the flow of the water in the water at the time of a high water level. FIG. 6 shows preferred dimensions associated with the diameter of the suction pipe. It is a top view which shows the suction water tank used for experiment. FIG. 12A is a graph showing experimental results using a pump device not equipped with a vortex prevention device, and FIG. 12B is a graph showing experimental results using a pump device equipped with a vortex prevention device. is there. It is a figure which shows the example which made the horizontal overhang | projection member rectangular. It is a figure which shows the example which made the horizontal projecting member polygonal shape. Fig.15 (a) and FIG.15 (b) are figures which show the example which provided the reinforcement rib and the drain hole. It is a top view which shows the modification of the vortex prevention apparatus which concerns on 2nd Embodiment. It is a longitudinal cross-sectional view which shows the vortex prevention apparatus shown in FIG. It is a top view which shows the example which changed the attachment position of the vortex prevention device. It is a top view which shows the further modification of the vortex prevention apparatus which concerns on 2nd Embodiment. It is a top view which shows the example which changed the attachment position of the segment of a vortex prevention device. FIG. 21A is a side view showing a vortex preventing device according to the third embodiment of the present invention, and FIG. 21B is a view of the vortex preventing device shown in FIG. It is. It is a side view which shows the modification of the vortex prevention apparatus which concerns on 3rd Embodiment. It is a side view which shows the further modification of the vortex prevention apparatus which concerns on 3rd Embodiment. FIG. 24A to FIG. 24D are views of a further modification of the vortex prevention device according to the third embodiment as viewed from below. Fig.25 (a) is a side view which shows the further modification of the vortex prevention apparatus which concerns on the 3rd Embodiment of this invention, FIG.25 (b) shows the vortex prevention apparatus shown to Fig.25 (a). It is the figure seen from the lower part. FIG. 26 (a) is a side view showing a vortex prevention device according to the fourth embodiment of the present invention, and FIG. 26 (b) is a cross-sectional view taken along the line BB of FIG. 26 (c) is a view of the vortex prevention device shown in FIG. It is a top view which shows the modification of the vortex prevention apparatus which concerns on 4th Embodiment. It is a side view which shows the further modification of the vortex prevention apparatus which concerns on 4th Embodiment. It is a front view which shows the further modification of the vortex prevention apparatus which concerns on 4th Embodiment. It is a top view which shows the further modification of the vortex prevention apparatus which concerns on 4th Embodiment. FIG. 31A and FIG. 31B are diagrams showing an example in which the vortex prevention device according to the fourth embodiment and the vortex prevention device according to the third embodiment are combined. FIG. 32 (a) is a schematic view showing a pump device provided with the vortex prevention device according to the fifth embodiment of the present invention, and FIG. 32 (b) shows the vortex prevention device shown in FIG. 32 (a). It is a perspective view. It is a top view which shows the modification of the vortex prevention apparatus which concerns on 5th Embodiment. It is a side view which shows the further modification of the vortex prevention apparatus which concerns on 5th Embodiment. It is the figure which combined the vortex prevention device shown to Fig.21 (a), and the vortex prevention device shown to Fig.32 (a). It is the figure which combined the 1st vortex prevention device shown to Fig.25 (a), and the 2nd vortex prevention device shown to Fig.32 (a). It is the figure which combined the vortex prevention apparatus shown to Fig.8 (a) and FIG.8 (b), and the vortex prevention apparatus shown in FIG.24 (c).

Embodiments of the present invention will be described below with reference to the drawings.
In addition, although embodiment described below is related with a horizontal-axis pump, this invention is not limited to this example, It can be used also for a vertical-axis pump and a submersible pump.

  FIG. 1 is a schematic view showing a pump device provided with a vortex preventing device according to a first embodiment of the present invention. As shown in FIG. 1, the pump device includes a pump 10 that transfers water from the suction water tank 1 to the discharge water tank 2 and a drive source 15 that drives the pump 10. The pump 10 communicates the pump casing 10a, an impeller (not shown) accommodated in the pump casing 10a, the suction pipe 11 that communicates the pump casing 10a and the suction water tank 1, and the pump casing 10a and the discharge water tank 2. And a discharge pipe 12. The discharge pipe 12 is provided with a discharge valve 13.

  The impeller is connected to a speed reducer (power transmission device) 18 via a rotating shaft 16, and the speed reducer 18 is connected to a drive source 15. As the drive source 15, a motor, a diesel engine, a gas turbine engine, or the like is used. The pump 10 is a so-called horizontal axis pump in which the rotary shaft 16 extends in the horizontal direction.

  The suction pipe 11 extends vertically, and a suction port 11 a formed at the lower end thereof is located in the water in the suction water tank 1. The lower end of the suction pipe 11 is configured as a bell mouth. The impeller of the pump 10 is arranged above the water surface in the suction water tank 1, and the pump casing 10 a is installed on the installation floor 20 constituting the upper part of the suction water tank 1 via a gantry 21. The downstream side portion of the suction pipe 11 is a curved pipe portion, whereby the suction pipe 11 and the pump casing 10a are smoothly connected. The discharge pipe 12 has a discharge port 12 a that opens in the discharge water tank 2. The discharge port 12 a is located at a position lower than the impeller of the pump 10. The discharge port 12a is provided with a flap valve 22 for preventing a reverse flow of the water transferred to the discharge water tank 2.

  As can be seen from FIG. 1, the suction pipe 11, the pump casing 10a, and the discharge pipe 12 form a siphon-type passage as a whole. A full water detector 30 having an electrode rod inside is provided in the upper part of the pump casing 10a, and the full water detector 30 detects whether the pump casing 10a is filled with water. Further, the inside of the pump casing 10 a communicates with the vacuum pump 31 via the full water detector 30.

  When starting the pump device, first, the vacuum pump 31 evacuates the inside of the pump casing 10a to form a negative pressure, and the water level in the suction pipe 11 is raised. When the full water detector 30 detects that the inside of the pump casing 10a is filled with water, the impeller is rotated by the drive source 15, the discharge valve 13 is opened, and thereby water is pumped up from the suction water tank 1. It is transferred to the discharge water tank 2.

  A vortex prevention device 35 according to this embodiment is attached to the lower end of the suction pipe 11. The vortex prevention device 35 includes a plate-like horizontal projecting member 35a that is disposed on the radially outer side of the suction port 11a and extends substantially horizontally from the suction port 11a. The horizontal projecting member 35a is fixed to the lower end of the suction pipe 11 so as to surround the suction port 11a. 2 is a cross-sectional view taken along line AA in FIG. As shown in FIG. 2, the vortex prevention device 35 has a fan-like shape as a whole and has an arcuate outer edge. The location where the vortex prevention device 35 is attached is downstream of the suction pipe 11 with respect to the flow of water. The vortex prevention device 35 is fixed to the suction pipe 11 by a fastener (not shown) such as a bolt or welding. The horizontal projecting member 35a may not be completely horizontal, and may be slightly inclined in consideration of drainage or the like.

  The vortex prevention device 35 is attached to the lower end portion of the suction pipe 11, and the joint location is not particularly limited. For example, as shown in FIG. 3A, the vortex prevention device 35 may be fixed to the upper surface of the flange formed at the lower end of the suction pipe 11, or as shown in FIG. The vortex prevention device 35 may be fixed to the outer peripheral surface. In FIG. 3A and FIG. 3B, the vortex prevention device 35 is represented by a cross section.

  The vortex prevention device 35 has a shape surrounding at least a part of the suction port 11a. The range in which the vortex prevention device 35 surrounds the suction port 11a may be the entire circumference of the suction port 11a, and is preferably less than or equal to a half circumference of the suction port 11a. 4 shows an example of the vortex prevention device 35 formed so as to surround the entire circumference of the suction port 11a, and FIG. 5 shows an example of the vortex prevention device 35 formed so as to surround the half circumference of the suction port 11a. FIG. As shown in FIG. 2, when θ is an angle formed by two lines connecting both end portions of the horizontal projecting member 35a of the vortex preventing device 35 and the center of the suction port 11a, the angle θ is 120 ° or more and 180 ° or less. It is preferable that

  As shown in FIG. 6, the air suction vortex is generated by developing a Karman vortex that is generated when the flow of water forming the free surface is divided by the suction pipe 11. Therefore, the Karman vortex is generated on the downstream side of the suction pipe 11. The Karman vortex is caused to flow downstream by the flow of water. Therefore, it is preferable that the vortex prevention device 35 is disposed on the downstream side with respect to the suction pipe 11.

In general, vortices are more likely to occur as the free surface of the water flowing through the suction tank 1 becomes gentler. The free surface state of water is represented by the Froude number, and this Froude number can be obtained by the following equation.
Fluid number (Fr) = v / (gh) ^1/2 (1)
However, v represents the flow velocity of water, g represents acceleration of gravity, and h represents water depth.
As the Froude number approaches 1, the water surface undulates, and as the Froude number approaches 0, the water surface becomes calmer. As can be seen from the equation (1), the fluid number approaches 0 as the water level increases.

  FIG. 7 is a view for explaining a state in which formation of the air suction vortex is prevented by the vortex prevention device 35. As shown in FIG. 7, the horizontal projecting member 35a of the vortex preventing device 35 can make the apparent water depth h 'at the low water level shallower than the actual water depth h (h' <h). Therefore, the free surface of the water flowing through the suction water tank 1 can be disturbed and the fluid number can be increased. Furthermore, even when a vortex is generated, the presence of the horizontal projecting member 35a on the path of the vortex can prevent growth from a Karman vortex to an air suction vortex. Thus, the horizontal overhanging member 35a can effectively prevent the air suction vortex particularly when the water level is low. Therefore, even if the flow velocity in the suction water tank 1 is the same, operation at a lower water level is possible. Therefore, the water level of the river can be lowered as much as possible in preparation for heavy rain, and the river can be prevented from overflowing.

  Thus, by providing the vortex preventing device 35 adjacent to the suction port 11a, it is possible to prevent the generation of the air suction vortex without performing civil engineering work such as digging the bottom plate of the suction water tank 1. The vortex preventing device 35 does not disturb the flow of water flowing into the suction port 11a, and does not impair the pump performance. Moreover, since the vortex prevention apparatus 35 which concerns on this embodiment is attached to the suction pipe 11, the fastening to the suction water tank 1 is unnecessary and the reinforcement construction of the suction water tank 1 is unnecessary. Furthermore, the vortex prevention device 35 can be easily attached to and replaced with the suction pipe 11, and the operation of the pump device need not be stopped for a long period of time for the vortex prevention device 35 to be attached or exchanged.

  FIG. 8A is a plan view showing a vortex prevention device 35 according to the second embodiment of the present invention, and FIG. 8B is a longitudinal sectional view of the vortex prevention device 35 shown in FIG. It is. The vortex prevention device 35 according to the present embodiment further includes a vertical overhang member 35b extending upward from the outer edge of the horizontal overhang member 35a. The horizontal projecting member 35a and the vertical projecting member 35b are integrally formed.

  When the water level in the suction tank 1 is high, the free surface of water is relatively gentle. Furthermore, since the actual head is lowered, the flow rate of water transferred by the pump 10 is increased due to the pump characteristics. Therefore, when the water level becomes high to some extent, vortices may be easily generated. The vertical projecting member 35b effectively prevents the formation of an air suction vortex when the water level is high. FIG. 9 is a diagram illustrating a flow of water in water at a high water level. As shown in FIG. 9, a stagnation portion is generated around the upper end of the vertical projecting member 35 b as surrounded by a dotted line. This stagnation part disturbs the flow of water in the course of the vortex and prevents the vortex from reaching the suction port 11a. Therefore, by providing the vertical projecting member 35b, it is possible to effectively prevent formation of an air suction vortex at a high water level.

  FIG. 10 shows preferred dimensions associated with the diameter of the suction pipe. As shown in FIG. 10, the diameter of the suction pipe 11 is represented by the symbol d. When the distance between the center of the suction pipe 11 and the rear wall of the suction water tank 1 is 1.5d or more, the distance from the center of the suction pipe 11 to the outer edge of the horizontal projecting member 35a is 1.25d or more. Is preferred. The height of the vertical projecting member 35b is preferably 0.4 d or more. The distance between the suction port 11a and the bottom of the suction water tank 1 is preferably 0.5d or more, and is generally in the range of 0.75d to 1.0d. When these preferable dimensions are set, the minimum water level of the suction water tank 1 in which the pump device can be operated can be lowered by 0.5 d or more as compared with the conventional pump device. When the distance between the center of the suction pipe 11 and the rear wall of the suction water tank 1 is less than 1.5d, the distance from the center of the suction pipe 11 to the outer edge of the horizontal projecting member 35a is less than 1.25d. can do. However, from the viewpoint of preventing the air suction vortex, the distance from the center of the suction pipe 11 to the outer edge of the horizontal projecting member 35a is preferably 1.25d or more. However, if the required dimensions cannot be secured, the “distance from the center of the suction pipe 11 to the rear wall” and the “distance from the center of the suction pipe 11 to the outer edge of the horizontal overhanging member 35a” may be substantially equal. Good.

  The vortex prevention device 35 according to the present embodiment has a horizontal overhang member 35a and a vertical overhang member 35b, and can perform stable pump operation over a wide range from a low water level to a high water level. Here, the experimental result using the pump apparatus provided with the vortex prevention apparatus 35 which concerns on this embodiment is demonstrated. FIG. 11 is a plan view showing the suction water tank used in this experiment. The distance between the center of the suction pipe 11 and the rear wall of the suction water tank 1 was 1.5d, and the width of the suction water tank 1 was 3d. The distance from the lower end of the suction pipe 11 to the water surface is S, and the submerged depth S / d and flow rate (%) of the pump (based on the conventional pump station design method dimensions, the proximity of the suction water tank at S / d = 1.7 o'clock) And the flow rate at which the flow velocity V becomes 0.25 m / s was taken as 100%). The experimental results are shown in FIGS. 12 (a) and 12 (b).

  FIG. 12A is a graph showing experimental results using a pump device that does not include a vortex prevention device, and FIG. 12B shows an experiment using a pump device that includes the vortex prevention device according to the present embodiment. It is a graph which shows a result. In FIG. 12A and FIG. 12B, symbol A1 represents a region where no air suction vortex was generated, and symbols A2 and A3 represent regions where the air suction vortex was confirmed. From this experimental result, it can be seen that the pump device provided with the vortex prevention device 35 can perform stable pump operation in a wide water level range as compared with the pump device not provided with the vortex prevention device.

  An angle formed by two lines connecting the both ends of the horizontal projecting member 35a and the center of the suction pipe 11 is θ1, and an angle formed by two lines connecting the both ends of the vertical projecting member 35b and the center of the suction pipe 11 is formed. Assuming that θ2, the angle θ1 is preferably not less than the angle θ2, the angle θ1 is preferably not less than 120 ° and not more than 360 °, and the angle θ2 is preferably not less than 120 °.

  The horizontal projecting member 35a may be rectangular or polygonal. FIG. 13 shows an example in which the horizontal projecting member 35a is rectangular, and FIG. 14 shows an example in which the horizontal projecting member 35a is polygonal. According to these examples, although the weight is slightly increased as compared with the fan-shaped horizontal projecting member 35a, machining is facilitated. Further, as shown in FIGS. 15 (a) and 15 (b), a plurality of reinforcing ribs 35c connecting the horizontal projecting member 35a and the vertical projecting member 35b are provided on the upper surface of the vortex preventing device 35 in order to ensure strength. Or you may provide in a lower surface. Furthermore, a drain hole 35d for preventing accumulated water may be provided in at least one of the horizontal projecting member 35a and the vertical projecting member 35b.

  16 is a plan view showing a modification of the vortex preventing device according to the second embodiment, and FIG. 17 is a longitudinal sectional view showing the vortex preventing device shown in FIG. As shown in FIGS. 16 and 17, a plurality of through holes 38 are formed at the lower end of the suction pipe 11 so as to surround the suction port 11a. These through holes 38 are arranged at equal intervals along the entire circumference of the suction port 11a. On the other hand, a plurality of through holes (not shown) are also formed at positions corresponding to the through holes 38 in the inner edge of the horizontal overhanging member 35 a of the vortex preventing device 35. The vortex prevention device 35 is detachably attached to the suction pipe 11 by a plurality of bolts 40 inserted into the through hole 38 of the suction pipe 11 and the through hole of the horizontal projecting member 35a.

  According to such a configuration, the position of the vortex prevention device 35 can be changed according to the flow direction of the water in the suction water tank 1. Therefore, as shown in FIG. 18, the vortex prevention device 35 can be easily adjusted and attached on site according to the situation of the installation site so as to be located on the downstream side of the suction pipe 11 with respect to the flow of water. Needless to say, this modification can also be applied to the first embodiment.

  FIG. 19 is a plan view showing a further modification of the vortex prevention device according to the second embodiment. The basic configuration is the same as the example shown in FIG. 16, but in this example, the vortex prevention device 35 is divided into a plurality of segments 35A. More specifically, the vortex prevention device 35 is equally divided in the circumferential direction of the suction port 11a. Each segment 35A of the vortex prevention device 35 is detachably attached to the suction port 11a by a bolt 40, as in the example of FIG.

  According to this example, the overall width of the vortex preventing device 35, that is, the angle θ in FIG. 2 can be changed according to the number of the segments 35A installed. In addition, as shown in FIG. 20, when there are a plurality of water flow directions, the segments 35A can be spaced apart from each other corresponding to the respective water flow directions. Needless to say, this modification can also be applied to the first embodiment. In addition, these embodiments are basically installed and connected to the suction port 11 so as not to affect the civil engineering frame. However, if there is no problem such as civil engineering strength, it may be configured by fastening to the civil engineering frame. Good.

  FIG. 21A is a side view showing a vortex preventing device according to the third embodiment of the present invention, and FIG. 21B is a view of the vortex preventing device shown in FIG. It is. As shown in FIGS. 21A and 21B, this vortex prevention device includes a base ring 49 fixed to the lower end of the suction pipe 11, and a suction plate 50 fixed to the lower surface of the base ring 49. have. The suction plate 50 projects downward from the suction port 11a in a substantially vertical direction, and extends along the radial direction of the suction port 11a. The length L from one end of the suction plate 50 to the other end is set to be larger than the diameter D of the suction port 11a. The water flowing into the suction port 11a is divided by the suction plate 50.

  The suction plate 50 is composed of a plurality of plate members extending radially outward from the center of the suction port 11a, and has a cross shape as a whole. A plurality of through holes (not shown) are formed in the base ring 49 at substantially equal intervals in the circumferential direction. The vortex preventing device is detachably attached to the lower end of the suction pipe 11 by a bolt 53 inserted into these through holes. Therefore, the direction of the suction plate 50 can be changed according to the flow of water flowing through the suction water tank 1. The base ring 49 may be fixed to the suction pipe 11 by welding. Further, the base ring 49 may be omitted, and the suction plate 50 may be directly fixed to the lower end of the suction pipe 11 by welding or the like.

  According to the vortex prevention device provided with such a suction plate 50, it is possible to suppress underwater vortices generated between the suction port 11 a and the bottom of the suction water tank 1. This underwater vortex is formed by the development of a swirling flow between the suction port 11 a and the bottom plate of the suction water tank 1, and is generated when the suction port 11 a is located near the bottom plate of the suction water tank 1. It's easy to do. The vortex prevention device of the present embodiment can effectively prevent the generation of the underwater vortex by causing the suction plate 50 to eliminate the swirling flow that causes the underwater vortex. Therefore, the suction port 11a can be arranged at a lower position than the conventional structure, and pumping at a low water level is possible. Moreover, since this vortex prevention device does not need to be fixed to the suction water tank 1 that is a civil engineering enclosure and can be attached to an existing pump device, it can be a low-cost and highly reliable pump device. Furthermore, since this vortex prevention device is not buried in the sludge etc. which accumulates on the bottom board of the suction water tank 1, the vortex prevention function can be exhibited permanently.

  From the viewpoint of preventing the underwater vortex, the suction plate 50 needs to have a certain height. Specifically, the height H of the suction plate 50 is preferably 0.1 d or more, where d is the inner diameter of the suction pipe 11. For example, the height H of the suction plate 50 is preferably set to 30 cm or more so that dust (particularly string-like dust) existing in water does not get tangled. Further, as shown in FIG. 22, the height of the plurality of plate members constituting the suction plate 50 may be different from each other. As shown in FIG. 23, the end of the suction plate 50 may protrude radially outward from the lower end of the suction pipe 11.

  The suction plate 50 of the present embodiment has a cross shape, but the present invention is not limited to this shape. For example, as shown in FIGS. 24 (a) to 24 (d), the shape of the suction plate 50 is I type (FIG. 24 (a)), minus type (FIG. 24 (b)), Y type (FIG. 24). (A)), T type (FIG. 24D) may be used. In any of these examples, the suction plate 50 extends in the radial direction through the center of the suction port 11a. Usually, the underwater vortex generated from the bottom of the suction tank 1 often enters the pump through the center of the suction port 11a. Since the suction plate 50 according to the present embodiment has a shape that passes through the center of the suction port 11a, it is possible to effectively prevent the growth of the underwater vortex and further to obstruct the course of the underwater vortex. .

  It is also possible to prepare a plurality of vortex prevention devices having suction plates 50 having different heights H and / or lengths L, and to select the vortex prevention devices according to the operation status at the installation site of the pump device. Moreover, depending on the suction water tank 1, underwater vortex may be generated not only from the bottom plate but also from the side wall. In such a case, it is preferable to arrange the suction plate 50 so as to obstruct the swirling flow generated from the side wall. For example, as shown in FIGS. 24 (b) to 24 (d), it is preferable to install a suction plate 50 having a facing surface against the flow of water.

  Fig.25 (a) is a side view which shows the modification of the vortex prevention apparatus which concerns on the 3rd Embodiment of this invention, FIG.25 (b) shows the vortex prevention apparatus shown to Fig.25 (a) from the downward direction. FIG. In this modification, the suction plate 50 is connected to the lower end of the suction pipe 11 via a spacer 55. More specifically, each end of the suction plate 50 is connected to the base ring 49 via the spacer 55. When viewed from the lateral direction, the suction plate 50 is separated from the suction port 11 a, and a gap W is formed in the vertical direction between the suction plate 50 and the base ring 49. Also in this example, the base ring 49 may be omitted and the spacer 55 may be directly fixed to the lower end of the suction pipe 11. The shape of the spacer 55 is not particularly limited, and for example, a rod-like or plate-like member is used.

  Thus, by separating the suction plate 50 from the suction port 11a, it is possible to reduce the head loss at the suction port 11a. That is, the suction water level can be lowered without affecting the pump performance. Furthermore, by providing the gap W, a dust passage passage is ensured, so that a highly reliable pump device free from clogging with dust is obtained. Here, from the viewpoint of preventing blockage by dust, the gap W is preferably 0.1 d or more (where d represents the inner diameter of the suction pipe 11).

  FIG. 26 (a) is a side view showing a vortex prevention device according to the fourth embodiment of the present invention, and FIG. 26 (b) is a cross-sectional view taken along the line BB of FIG. 26 (c) is a view of the vortex prevention device shown in FIG. In this example, the suction plate 50 is not provided, and two fins 58 are attached to the outer peripheral surface of the suction pipe 11 instead.

  The fin 58 is located on the radially outer side of the suction port 11a and is disposed symmetrically with respect to the center of the suction port 11a. These fins 58 are disposed substantially perpendicular to the flow direction of the water flowing in the suction water tank 1. Further, the fins 58 are disposed in proximity to both side walls of the suction water tank 1. With such an arrangement, the water flowing in the suction water tank 1 collides with the fins 58 and is guided to the side wall to form a flow that obstructs the swirling flow generated on the side wall. Therefore, the swirling flow generated on the side wall is suppressed by the water flow guided by the fins 58, and the water flow vortex generated from the side wall can be effectively prevented.

  In the present embodiment, two fins 58 are provided, but one fin may be provided, or three or more fins may be provided. For example, one fin may be provided only on the side where the swirl flow is generated. FIG. 27 shows an example in which three fins are provided. In this example, in addition to the two fins 58 described above, a third fin 58 is disposed close to the rear wall of the suction water tank 1. Thus, by providing a fin also on the rear wall side, the flow of water on the rear wall can be changed, and an underwater vortex generated from the rear wall can be prevented. The number of fins is preferably determined according to the shape of the suction water tank 1.

  As shown in FIG. 28, the fins 58 may be slightly inclined with respect to the vertical direction. The angle α of the fin 58 with respect to the vertical direction can be appropriately determined according to the shape of the suction water tank 1. Moreover, as shown in FIG. 29, it is good also as a shape which protrudes the fin 58 below from the suction inlet 11a. If comprised in this way, not only the swirling flow from a side wall but the swirling flow from a bottom board can be suppressed. Furthermore, as shown in FIG. 30, the fins 58 may be slightly inclined from the direction perpendicular to the water flow in the suction water tank 1. This inclination angle β can be appropriately determined according to the generation position of the swirling flow on the side wall. The fins 58 according to this embodiment may be combined with the vortex prevention device according to the third embodiment. For example, as shown in FIG. 31A, the fins 58 may be attached to the end portions of the suction plate 50, and as shown in FIG. 31B, the fins 58 may be attached to the spacers 55.

  FIG. 32 (a) is a schematic view showing a pump device provided with the vortex prevention device according to the fifth embodiment of the present invention, and FIG. 32 (b) shows the vortex prevention device shown in FIG. 32 (a). It is a perspective view. The vortex prevention device according to the present embodiment is disposed inside the suction pipe 11. As shown in FIG. 32 (b), this vortex prevention device is composed of a plurality of partition plates 60 that divide the flow path in the suction pipe 11 into a plurality of flow paths. The partition plate 60 is disposed along the longitudinal direction of the suction pipe 11 (that is, substantially parallel to the suction pipe 11). In the example shown in FIG. 32A, the partition plate 60 extends in the vertical direction and has a cross-shaped cross section. Therefore, in this example, the flow path in the suction pipe 11 is divided into four flow paths.

  According to the vortex prevention device according to the present embodiment, the following effects can be obtained. That is, even if an underwater vortex enters the suction pipe 11, the underwater vortex can be eliminated by the partition plate 60 before reaching the impeller of the pump. That is, the energy of the swirl flow is divided by the partition plate 60, and these energy are reduced by the friction loss of the flow path. As a result, the underwater vortex can be eliminated before reaching the impeller.

  As in FIGS. 24A to 24D, the cross-sectional shape of the partition plate 60 is I type (FIG. 24A), minus type (FIG. 24B), and Y type (FIG. 24). 24 (a)) or T-type (FIG. 24 (d)). In any shape, the shape and arrangement of the partition plate 60 are determined so as to pass through the central axis of the suction pipe 11. Usually, the underwater vortex generated from the bottom of the suction water tank 1 is generated on the central axis of the suction pipe 11 and often enters the pump through the center of the suction port 11a. Since the partition plate 60 according to the present embodiment has a shape that passes through the central axis of the suction pipe 11, it is possible to effectively prevent the growth of the underwater vortex and further obstruct the course of the underwater vortex. it can.

  As shown in FIG. 33, the partition plate 60 may protrude downward from the suction port 11a. Thus, the swirling flow from the bottom plate can be suppressed by positioning the lower end of the partition plate 60 below the suction port 11a. Further, as shown in FIG. 34, one or a plurality of convex portions 61 may be provided on the inner peripheral surface of the suction pipe 11 in order to change the flow of water in the suction pipe 11. Such a convex part can further reduce the energy of the swirling flow and more reliably prevent the entry of the underwater vortex.

  The vortex prevention device according to the present embodiment can be appropriately combined with the vortex prevention devices according to the third and fourth embodiments described above. For example, FIG. 35 is a diagram in which the first vortex prevention device (suction plate 50) shown in FIG. 21 (a) and the second vortex prevention device (partition plate 60) shown in FIG. 32 (a) are combined. FIG. 36 is a diagram in which the first vortex prevention device (suction plate 50) shown in FIG. 25 (a) and the second vortex prevention device (partition plate 60) shown in FIG. 32 (a) are combined. is there.

  Further, the first or second embodiment for preventing the air suction vortex, the third embodiment for preventing the underwater vortex, and / or the fourth embodiment, and / or the fifth embodiment are combined. Also good. For example, as shown in FIG. 37, the vortex prevention device shown in FIGS. 8 (a) and 8 (b) can be combined with the vortex prevention device shown in FIG. 24 (c). By adopting such a combination, air suction vortex and underwater vortex can be effectively prevented.

  The embodiment described above is described for the purpose of enabling the person having ordinary knowledge in the technical field to which the present invention belongs to implement the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Therefore, the present invention should not be limited to the described embodiments, but should be the widest scope according to the technical idea defined by the claims.

DESCRIPTION OF SYMBOLS 1 Suction water tank 2 Discharge water tank 10 Pump 10a Pump casing 11 Suction pipe 11a Suction port 12 Discharge pipe 13 Discharge valve 15 Drive source 16 Rotating shaft 18 Reduction gear 20 Installation floor 21 Base 22 Flap valve 30 Full detector 31 Vacuum pump 35 Vortex prevention Device 35a Horizontal projecting member 35b Vertical projecting member 35c Reinforcement rib 35d Drain hole 38 Through hole 40 Bolt 50 Suction plate 58 Fin 60 Partition plate

Claims (16)

A vortex prevention device attached to a suction pipe of a pump,
A vortex prevention device comprising a plate-like horizontal projecting member that is disposed radially outside the suction port of the suction pipe and extends substantially horizontally.   The vortex prevention device according to claim 1, wherein the horizontal projecting member is disposed on the downstream side of the suction pipe with respect to a liquid flow direction.   The vortex prevention device according to claim 1, further comprising a plate-like vertical projecting member extending upward from an outer edge of the horizontal projecting member.   The vortex prevention device according to claim 1, wherein the vortex prevention device includes a plurality of segments that are equally divided in a circumferential direction of the suction port. A pump device for pumping the liquid in the suction water tank,
A pump having a suction pipe disposed in the suction water tank;
A drive source for driving the pump;
A vortex prevention device attached to the suction pipe,
The pump device according to claim 1, wherein the vortex preventing device includes a plate-like horizontal projecting member that is disposed radially outside the suction port of the suction pipe and extends substantially horizontally.   The pump device according to claim 5, wherein the horizontal projecting member is disposed on the downstream side of the suction pipe with respect to the flow direction of the liquid.   The pump device according to claim 5, wherein the vortex preventing device further includes a plate-like vertical projecting member extending upward from an outer edge of the horizontal projecting member. A plurality of first through holes are formed at the lower end of the suction pipe so as to surround the suction port,
A plurality of second through holes are formed at positions corresponding to the first through holes on the inner edge of the horizontal projecting member,
The pump device according to claim 5, wherein the vortex prevention device is detachably attached to the suction pipe by a fastening member inserted into the first through hole and the second through hole. .   The pump device according to claim 5, wherein the vortex prevention device includes a plurality of segments that are equally divided in a circumferential direction of the suction port. A vortex prevention device attached to a suction pipe of a pump,
A vortex prevention device comprising a suction plate extending downward from a suction port of the suction pipe.   The vortex prevention device according to claim 10, wherein the suction plate is larger than a diameter of the suction port. The suction plate is connected to the suction port via a spacer,
The vortex prevention device according to claim 10, wherein the suction plate is separated from the suction port. And further comprising at least one fin disposed on a radially outer side of the suction port,
The vortex preventing device according to any one of claims 10 to 12, wherein the fins are disposed substantially perpendicular to a flow direction of the liquid flowing in the suction water tank. A vortex prevention device attached to a suction pipe of a pump,
Comprising at least one fin disposed radially outside the suction port of the suction pipe;
The vortex preventing device according to claim 1, wherein the fin is disposed substantially perpendicular to a flow direction of the liquid flowing in the suction water tank. A vortex prevention device attached to a suction pipe of a pump,
A partition plate arranged in the suction pipe and dividing the flow path in the suction pipe into a plurality of flow paths;
The vortex prevention device according to claim 1, wherein the partition plate is disposed substantially parallel to the suction pipe. A pump device for pumping the liquid in the suction water tank,
A pump having a suction pipe disposed in the suction water tank;
A drive source for driving the pump;
A pump device comprising the vortex preventing device according to any one of claims 11 to 15.

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