JP2008064088A - Vertical shaft pump and pump plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vertical shaft pump and a pump plant stably operating even if water level lowers by more surely sucking air when the water level lowers or suited for precursory standby operation. <P>SOLUTION: The vertical shaft pump comprises a rotary shaft 21 vertically arranged and axially rotating, an impeller 20 rotating with the rotation of the rotary shaft, sucking and sending water upward, the impeller being disposed downstream of a lower end 23 of the rotary shaft, a suction pipe 31 disposed upstream of the impeller and letting water flow toward the impeller, an air pipe 40 connected at one end to the suction pipe and sucking air from the other end, a bearing 50 disposed upstream of the impeller and rotatably supporting the rotary shaft and a support member 60 interconnecting the suction pipe and the bearing, formed with a hollow portion communicating with the air pipe and formed with a hole 62 extending from an outer surface to the hollow portion. The pump plant includes at least two vertical shaft pumps in which the impellers are disposed at different levels. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vertical pump and a pump station, and more particularly, to a vertical pump and a pump station suitable for a prior standby operation.

Conventionally, as shown in FIG. 7, an impeller 112 is provided at the tip of a shaft arranged in the vertical direction, and the impeller 112 sucks air together with water, so that the operation is continued even below the minimum water level LWL of the suction water tank 111. There was a vertical pump 113 that made it possible. In the pump 113, the h ≒ ^v 2 / hole 115 of 2g intake passing through the position lower LLWL from the water level LWL to the upstream side of the suction pipe 114 from the impeller 112 provided, the mounting position of the impeller 112 in the bore 115 An air pipe 116 having the other end 116a that opens upward is attached. Here, v is the flow velocity of the water in that portion, and g is the acceleration of gravity. As a result, below the minimum water level LWL, the amount of drainage is gradually reduced by the air flowing in through the holes 115, thereby avoiding a sudden pumping stop due to a drop in the water level and lower than the installation position of the impeller 112. Even when the water level rises from the water level, the rapid start of pumping is avoided by reducing the amount of drainage with the air flowing in through the hole 115 until the water level reaches the lowest water level LWL. In such a vertical shaft pump, it is possible to prevent vibration due to the suction vortex being drawn from the suction pipe 114 when the water level is lowered.

In this way, for example, for rainwater drainage in large cities, the pump is started in advance according to rainfall information etc. regardless of the suction water level, and when the water level rises from the low water level, the total amount is increased while gradually increasing the water amount from the idle operation When the water level dropped from the high water level to the operation, it was possible to smoothly shift the operation from the full operation to the empty operation while gradually reducing the water amount. However, if the water level is lower than the minimum water level LWL and an attempt is made to intake air through the air pipe 116, a positive pressure is generated in the intake hole 115 due to the swirling flow below the impeller, and the water level becomes lower than LWL. In some cases, sufficient intake was not performed. In view of this, there has been proposed a vertical shaft pump in which the rotating shaft 117 of the impeller 112 is extended to the upstream side, a bearing that supports the lower end of the rotating shaft is provided, and a swirling flow is prevented by a support plate that connects the bearing and the pump casing. (See Patent Document 1).
Japanese Patent Laying-Open No. 2006-189016 (FIG. 1)

However, in the above-described vertical shaft pump, the swirling flow is not always completely prevented, and if the swirling flow remains, a positive pressure may be generated in the intake hole and sufficient intake may not be performed. .
Accordingly, the present invention provides a vertical shaft pump and a pump station that can perform intake even more reliably if the water level drops and can perform stable operation even if the water level drops, that is, suitable for the preceding standby operation. With the goal.

  In order to achieve the above object, the vertical pump according to the first aspect of the present invention includes, for example, a rotating shaft 21 that is arranged in the vertical direction and rotates around the axis as shown in FIG. An impeller 20 that rotates and sucks water and flows upward, the impeller 20 being disposed on the downstream side of the lower end 23 of the rotation shaft 21; disposed on the upstream side of the impeller 20, toward the impeller 20. A suction pipe 31 forming a flow path for flowing water; an air pipe 40 having one end connected to the suction pipe 31 and sucking air from the other end; disposed upstream of the impeller 20 and capable of rotating the rotary shaft 21 A supporting member 60 that connects the suction pipe 31 and the bearing 50, and has a hollow portion that communicates with the air pipe 40 and a hole 62 that extends from the outer surface to the hollow portion. With.

  With this configuration, the rotating shaft can be supported at two locations on the upstream side and the downstream side of the impeller, reducing the burden on each bearing and suppressing vibration caused by the rotation of the impeller. Driving is stable. This is particularly effective for non-water-filled bearings. Further, the rotating shaft can be supported in the vicinity of the lower end thereof, and the rotating shaft is lubricated even in the non-water supply operation, and the preceding standby operation is smoothly performed. Furthermore, when the water level drops and the air is sucked from the air pipe, the air is sucked into the suction pipe through the hole formed in the support member. Is called.

  Moreover, in the vertical shaft pump according to claim 2, for example, as shown in FIG. 3, in the vertical shaft pump according to claim 1, the cross-sectional shape of the support member 60 is flat.

  If comprised in this way, since the cross-sectional shape of a support member is flat, a support member has an effect | action as a baffle plate which prevents a turning flow, and a turning flow is prevented.

  Further, in the vertical shaft pump according to claim 3, for example, as shown in FIG. 1 and FIG. 4, in the vertical shaft pump 10 according to claim 1 or 2, the hole 62 formed in the support member 60 has a suction A plurality of arrays are arranged in a direction from the connection portion 64 with the pipe 31 to the connection portion 66 with the bearing 50. Here, the connection portion 66 with the bearing 50 includes a connection portion 66 with the bearing box 52 that houses the bearing 50 in addition to the case of directly connecting with the bearing 50. That is, the support member 60 may connect the suction pipe 31 and the bearing 50 via the bearing box 52 without directly connecting the suction pipe 31 and the bearing 50.

  If comprised in this way, since the air attracted | sucked from the air pipe will be disperse | distributed and mixed with water over the whole range of the flow-path cross section from a bearing to the inner surface of a suction pipe, it will become easy to become the gas-liquid mixed flow mixed uniformly.

  Further, in the vertical shaft pump according to claim 4, for example, as shown in FIG. 1, in the vertical shaft pump according to any one of claims 1 to 3, the hole 62 formed in the support member 60 is It is formed on the rotational direction side of the impeller 20.

  When configured in this manner, when the air level is lowered and air is sucked from the hole formed in the support member, the hole is located on the back pressure side with respect to the swirl flow in the support member, The intake air is surely taken in without being damaged by the swirl flow.

  Further, in the vertical pump according to claim 5, for example, as shown in FIGS. 1 and 5, the vertical pump is formed on the support member 60 in the vertical pump 10 according to any one of claims 1 to 3. The opening of the hole 62 is formed upward.

  With this configuration, when the air level is lowered and air is sucked from the hole formed in the support member, even if a swirling flow is generated, the hole is not affected by the positive pressure due to the swirling flow, and thus becomes a negative pressure. The intake air is not impaired by the swirl flow.

  Moreover, in the vertical shaft pump according to claim 6, for example, as shown in FIG. 1, in the vertical shaft pump according to any one of claims 1 to 5, the hole 62 formed in the support member 60 is It is formed at the lowest operating water level LLWL.

  With this configuration, when the water level drops and reaches the minimum water level, air is sucked from the hole through the hollow portion of the support member from the air pipe, and air suction from the suction pipe is suppressed. The problem of vibration and noise associated with air suction can be avoided. Here, “the hole formed in the support member is formed at the minimum operating water level” is only required to be substantially formed at the minimum operating water level, with a margin above the calculated minimum operating water level. It includes the case where it is formed.

  In order to achieve the above object, a pump station 101 according to the invention described in claim 7 includes a plurality of vertical shaft pumps 10 according to any one of claims 1 to 6 as shown in FIG. 6, for example. (10a, 10b, 10c); the plurality of vertical pumps 10 include at least two vertical pumps 10 in which the impellers 20 are arranged at different heights.

  If comprised in this way, since the vertical shaft pump from which the water level which begins to discharge water and finishes is different is provided, it can prevent performing excessive drainage and can also reduce the load with respect to a power supply device.

  According to the present invention, the vertical pump is a rotary shaft that is arranged in the vertical direction and rotates around the shaft, and an impeller that rotates by the rotation of the rotary shaft and sucks water to flow upward, downstream from the lower end of the rotary shaft. A disposed impeller, a suction pipe disposed upstream of the impeller to form a flow path for flowing water toward the impeller, an air pipe having one end connected to the suction pipe and sucking air from the other end, and the blade A bearing that is disposed upstream of the vehicle and rotatably supports the rotating shaft, and a support member that connects the suction pipe and the bearing, a hollow portion that communicates with the air pipe is formed, and a hole that extends from the outer surface to the hollow portion is formed Since it is provided with the formed support member, the rotation shaft can be supported at two locations on the upstream side and the downstream side of the impeller, reducing the burden on each bearing and suppressing vibration due to the rotation of the impeller, The operation of the vertical axis pump is stabilized. In addition, when the water level drops and the air is sucked from the air pipe, the air is sucked into the suction pipe through the hole formed in the support member. Is called. Therefore, if the water level is lowered, intake is performed more reliably, and stable operation can be performed even if the water level is lowered, that is, the vertical shaft pump is suitable for the preceding standby operation.

  The pump station includes a plurality of the above-described vertical shaft pumps, and the plurality of vertical shaft pumps include at least two vertical shaft pumps in which the impellers are arranged at different heights. A vertical shaft pump having a different water level is provided, so that excessive drainage can be prevented and the load on the power supply device can be reduced. That is, it becomes a pump station suitable for the advance standby operation.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or corresponding devices are denoted by the same reference numerals, and redundant description is omitted.

  First, with reference to FIG. 1, the vertical shaft pump which is the 1st Embodiment of this invention is demonstrated. FIG. 1A is a cross-sectional configuration diagram showing a cross section of a main part of the vertical shaft pump 10 and a configuration of an air pipe 40 that is a part of the vertical shaft pump 10 and related devices, and FIG. 1B is a bottom view. . The vertical shaft pump 10 is a pump for preceding standby operation. Advance standby operation, especially full-speed advance standby operation, starts the pump in advance before rainwater flows into the suction tank, starts draining as the water level rises, and operates at full speed without stopping the pump even if the water level falls It is to be. The vertical shaft pump 10 is disposed in a water tank 1 that is a suction water tank that primarily stores rainwater and the like, and discharges water stored in the water tank 1.

  The structure of the vertical shaft pump 10 will be described with reference to FIG. The vertical shaft pump 10 includes a pumping pipe casing (casing body) 33, a liner casing 32, and a suction pipe (suction bell) 31 arranged in the vertical direction from above. Each is fastened by horizontal flanges 37 and 36. These constitute a casing in a broad sense.

A rotating shaft 21 is arranged in the longitudinal direction (vertical direction) at the center of the casing. The vicinity of the lower end 23 of the rotating shaft 21 is rotatably supported by a bearing 50. An open impeller 20 is attached below the rotary shaft 21 and above the bearing 50. The impeller may be a closed type. The liner casing 32 accommodates the impeller 20 with a slight gap from the outer periphery of the impeller 20 (the tip of the open blade). The vertical shaft pump 10 is a mixed flow pump. A mixed flow pump is used when the discharge head is relatively large. A guide vane 35 is disposed on the discharge side of the impeller 20 and on the inner side of the casing body 33.
An axial flow pump (not shown) may be used as the pump for the preceding standby operation. The axial flow pump is suitable when the flow rate is relatively large with respect to the discharge head.

  The casing body 33 is configured to include a vertical tube body portion parallel to the rotation shaft 21, a bent tube portion bent in the horizontal direction above, and a horizontal tube portion connected to the bent tube portion. Has penetrated. The penetrating tip is connected to an electric motor (not shown) as a drive device that rotationally drives the rotary shaft 21. The electric motor may not be directly connected to the rotating shaft 21 but may be connected through a gear train, for example, so that the rotation speed can be adjusted. A seal 22c is disposed in the penetrating portion to prevent water leakage through the penetrating portion. In addition, it is preferable to dispose a bearing (not shown) between the seal 22c and the driving device because vibration due to the driving device is prevented. The rotary shaft 21 is supported at three points by a bearing 22a disposed in the vicinity of the impeller 20, a bearing 22b disposed between the bearing 22a and the seal 22c, and the bearing 50 described above. If a bearing (not shown) is disposed between the seal 22c and the drive device as described above, four-point support is provided. By supporting the rotating shaft 21 in this way, particularly by supporting the rotating shaft 21 on both sides of the impeller 20, the burden on each bearing can be reduced, so that the life of the bearing is extended and the maintenance period is extended. be able to. Furthermore, the vibration accompanying rotation of the rotating shaft 21 can be suppressed. A thrust bearing (not shown) supports a load in the vertical direction applied to the rotating shaft 21 (that is, the weight of the rotating body including the impeller 20 and the rotating shaft 21 and the fluid force applied to the impeller 20).

  A flange 39 for installation is attached to the casing main body 33, and the flange 39 is installed on the concrete floor 2 as an installation table. A flange 38 is attached to the horizontal pipe portion of the casing body 33, and is connected to the discharge pipe 34 by the flange 38. The discharge pipe 34 is a pipe for guiding rainwater to a river or the sea and discharging it.

  The suction pipe 31 is positioned below the tip of the impeller 20 and forms a flow path 90 through which water flows through the impeller 20. The suction pipe 31 has an opening end that is expanded in a bell shape at the lower end, that is, upstream of the flow of water, sucks water in the water tank 1 from the opening end, and feeds it toward the impeller 20. Because of its shape, it is sometimes called a suction bell. By expanding the opening end, the flow velocity at the opening end of the suction pipe 31 when sucking in the water in the water tank 1 is lowered and vibrations are less likely to occur. However, the diameter is not necessarily expanded, for example, a cylindrical shape with a uniform diameter It may be.

  An air pipe 40 is connected to the outside of the suction pipe 31. The air pipe 40 communicates with an air flow path 44 formed inside the suction pipe 31. The air pipe 40 has an end 41 that is the other end opened to the atmosphere, and guides air from the atmosphere to the air flow path 44. The end 41 of the air tube 40 that is open to the atmosphere is preferably turned downward by a U-shaped tube as shown in FIG. In FIG. 1, the end 41 is located above the floor 2, but may be located in the water tank 1 below the floor 2. As will be described later, when the water level becomes the lowest water level LWL and air is sucked into the suction pipe 31 through the air pipe 40, the end portion 41 only needs to be exposed to the atmosphere. The number of air pipes 40 may be one, but a plurality of air pipes, for example, four, is preferable because air sucked from the air pipe 40 can easily flow into the air flow path 44.

  The air flow path 44 is an annular space formed inside the suction pipe 31 and is a flow path for dispersing the air sucked from the air pipe 40 in the circumferential direction inside the suction pipe 31. In the cross-sectional view of FIG. 1A, the air flow path 44 is shown as being open inward, but the inner side is also sealed except for a portion communicating with a support member 60 described later. The air flow path 44 may not be provided, and the air pipe 40 may be connected to each of the plurality of support members 60.

  A bearing 50 is disposed inside the suction pipe 31. The bearing 50 is housed in a bearing box 52 and fixedly supported by the bearing box 52. The height at which the bearing 50 is disposed is in the vicinity of the minimum operating water level LLWL. The minimum operating water level LLWL will be described later in detail.

  The bearing box 52 is supported by the support member 60. The support member 60 fixes the bearing box 52 at a predetermined position by connecting the inner surface of the suction pipe 31 and the bearing box 52. The bearing 50 is not necessarily housed in the bearing housing 52, and the bearing 50 and the support member 60 may be directly connected. In any case, the support member 60 is included in the concept of connecting the bearing 50 and the suction pipe 31. In FIG. 1B, the bearing housing 52 is fixedly supported by four support members 60. However, the number of the support members 60 is not limited to four, and may be one, two, three, or Five or more may be sufficient. A single cantilever beam is easy to deform and difficult to fix, but the structure is simple. Increasing the number can fix more firmly, and gas-liquid mixing is performed more uniformly when air is sucked from the holes 62 of the support member 60 as will be described later. However, if the number is too large, the structure becomes complicated, the flow area of the cross section becomes narrow, and water hardly flows. In general, therefore, three or four are appropriate from the viewpoint of strength and structure simplification.

  The support member 60 is formed in a hollow shape, and the hollow portion communicates with the air flow path 44. That is, the air guided to the air flow path 44 through the air pipe 40 reaches the hollow portion of the support member 60. A hole 62 is formed in the support member 60 from the outer surface to the hollow portion. Therefore, the air sucked from the air pipe 40 is guided to the water flow path 90 in the suction pipe 31 through the hole 62.

  Here, the relationship between the structure of the vertical pump 10 in the height direction and the water level will be described. The water level HWL is the highest water level of the water tank 1. The water level will not rise any further. Below that is the lowest water level LWL. This is a value peculiar to the pump. If the water level falls below this level, some problem occurs and the pump cannot continue to operate. Typically, below this level, the water starts to be sucked from the lower end of the suction pipe 31 in a vortex shape, causing vibrations and noises, so that the operation cannot be continued. However, the minimum water level LWL may be determined under conditions other than the spiral air suction.

  Below the lowest water level LWL is the suction start water level SLWL of the impeller 20. This water level corresponds to the water level at the tip of the impeller 20. This is because when the water level rises from a low water level and the impeller 20 comes into contact with water, the air-water stirring is started and water is discharged soon. That is, the impeller 20 is installed below the lowest water level LWL. Usually, the lowest operating water level LLWL of the vertical pump 10 is at a position lower than the suction start water level SLWL. Below the minimum operating water level LLWL, there is a water level A1 at the lower end (opening) of the suction pipe 31.

Here, the hole 62 of the support member 60 is disposed at the height of the minimum operating water level LLWL. The lowest operating water level LLWL is a position lower than the lowest water level LWL by h≈v ² / 2g. Here, v is the flow velocity of water at that position, and g is the weight acceleration. That is, since the pressure is lowered by the amount of velocity head according to Bernoulli's theorem due to the flow of water, the pressure is zero (atmospheric pressure) at the position where the head becomes equal to the velocity head at the lowest water level LWL. This position is defined as the minimum operating water level LLWL. If it does in this way, when a water level will become below the lowest water level LWL, it will become a negative pressure in the position of the lowest operating water level LLWL. Therefore, since the hole 62 arranged at the lowest operating water level LLWL has a negative pressure and communicates with the atmosphere through the hollow portion of the support member 60, the air flow path 44, and the air pipe 40, the hole 62 starts from the end 41 of the air pipe 40. Air is sucked into the suction pipe 31. By sucking air from the hole 62, air is not sucked in from the lower end of the suction pipe 31, and problems such as vibration and noise do not occur, and the operation can be continued as it is. Strictly speaking, the upper end of the hole 62 is set to the minimum operating water level LLWL. However, since the flow velocity is actually not constant, the hole 62 is generally disposed slightly above the calculated minimum operating water level LLWL. Also in this case, the hole 62 is disposed substantially at the lowest operating water level LLWL. In addition, the hole 62 should just be arrange | positioned above the minimum operating water level LLWL. As a result, air suction starts before the water level drops to the lowest water level LWL, but the problem of sucking air in a spiral shape from the tip of the suction pipe 31 and causing vibration or the like can be prevented more reliably. However, it is not preferable to dispose too much above because water cannot be sucked at a low water level. In the following description, it is assumed that the hole 62 is disposed at the lowest operating water level LLWL.

  When the water level drops to the minimum operating water level LLWL, the air pipe 41, the air passage 44, and the hole 62 through the hollow part of the support member 60 are opened to the atmosphere through the air pipe tip 41, and the space in the suction pipe 31 is opened. The vacuum breaks and the water in the suction pipe 31 falls. That is, when the water level is lowered to the height at which the hole 62 is formed, the vertical shaft pump 10 stops pumping.

  Next, the operation of the vertical shaft pump 10 will be described with reference to FIG. First, the vertical pump 10 is started in a state where the water level is lower than the water level A1 at the lower end (opening) of the suction pipe 31. For example, when there is rainfall information indicating that heavy rain has fallen upstream of the river, it is predicted that the water level will suddenly rise after a certain time. In such a case, the vertical pump 10 for the preliminary standby operation is started in a state where the water level is lower than A1. This is the start of the preceding standby operation.

  The water level in the water tank 1 rises due to the inflow of rainwater, and exceeds the lower end water level A1 of the suction bell. Even if the water level exceeds the water level A1 or exceeds the minimum operating water level LLWL, water is not yet sucked up. The impeller 20 is idling. When the water level further rises and reaches the suction start water level SLWL, the impeller 20 starts to suck water. At this time, since the air is also sucked into the suction pipe 31 from the hole 62 through the air pipe 40, the air flow path 44, and the hollow portion of the support member 60, it is not the operation of discharging the total water amount of the vertical pump 10. That is, the vertical shaft pump 10 is in the air / water mixing operation. When the water level further rises, the amount of intake air gradually decreases and the amount of water increases instead. Eventually, when the water level rises to the lowest water level LWL, the intake air amount becomes zero, and the total water amount of the vertical shaft pump 10 is discharged. That is, the steady operation is started.

  Furthermore, the water level rises to a water level between the lowest water level LWL and the highest water level HWL, and the pump 10 continues the steady operation. Thereafter, when the water level is lowered due to the drainage of the pump 10 and falls below the minimum water level LWL, air starts to be sucked into the suction pipe 31 from the hole 62 through the hollow portions of the air pipe 40, the air flow path 44 and the support member 60. That is, the air / water mixing operation is started again. As the water level falls, the amount of intake air increases and the amount of water decreases instead. When the water level further decreases and reaches the minimum operating water level LLWL, the suction of water is finished, and the impeller 20 enters an idling state in which it is operated in the air. That is, the vertical shaft pump 10 is in an air lock state in which no water is sucked.

  In this way, the impeller 20 continues the idling state in the air. When the rain continues, the operation is continued as it is, the water level rises again, and the vertical pump 10 starts to suck in water when it reaches the suction start water level SLWL as described above. In this way, the vertical shaft pump 10 for the preliminary standby operation can continue operation between the idle operation and the operation of the total water amount regardless of the water level of the water tank 1. The transition between the idle operation and the total water amount operation is smoothly performed because the vertical shaft pump 10 sucks air together from the hole 62 of the support member 60.

  Next, the support member 60 will be described in detail with reference to FIGS. 2A and 2B are diagrams for explaining typical examples of the cross-sectional shape of the support member 60, where FIG. 2A is a circular cross-sectional shape, FIG. 2B is an elliptical cross-sectional shape, FIG. 2C is a rectangular (rectangular) cross-sectional shape, and FIG. Shows a rounded rectangular cross-sectional shape. The cross-sectional shape of the support member 60 is arbitrary, but if it is circular as shown in (a), it is easy to manufacture, and a commercially available pipe can be used when the suction pipe 31 has a steel plate welded structure. When the flat shape is used as in (b) to (d), an action as a baffle plate for preventing the swirling flow caused by the rotation of the impeller 20 is obtained. Further, when the support member 60 has an elliptical cross-sectional shape as shown in (b), since there are no corners, the flow of water around the support member 60 becomes smooth. When the support member 60 has a rectangular cross-sectional shape as shown in FIG. When the support member 60 has a rounded rectangular cross-sectional shape as shown in (d), it is easy to manufacture, especially when cast together with the suction pipe 31, and there is no corner, so that the water flow around the support member 60 flows. Smooth. Typically, a rounded rectangular cross-sectional shape shown in (d) is used.

  Here, with reference to FIG. 3, the effect | action as a baffle plate of the supporting member 60 is demonstrated. FIG. 3 is a diagram for explaining the positional relationship with the flow of water when the support member 60 having a rectangular cross-sectional shape is used. 3A shows a case where the flat direction of the support member 60 is vertical, and FIG. 3B shows a case where the support member 60 is inclined at an angle α from the horizontal plane. In the figure, thick arrows indicate the direction of water flow when the flow rate is high, and thin arrows indicate the direction of water flow when the flow rate is low. That is, when the flow rate is small, the influence of the swirl flow appears strongly, and the horizontal component becomes significant in the water flow direction.

  In addition, the flat direction of the support member 60 is, for example, a cross-section of a support member having a flat cross-sectional shape such as an elliptical cross-sectional shape shown in FIG. 2B or a rectangular cross-sectional shape shown in FIG. The direction of the longest diameter. When the support member has a twisted cross-sectional shape, the longest diameter in the cross section is taken as an average direction.

  When the support member 60 is installed with the flat direction vertical as shown in FIG. 3A, the resistance to water flow is small when the flow rate is large, but the swirl flow (horizontal flow) when the flow rate is small. It acts as a baffle plate that prevents swirling flow. As shown in FIG. 3B, the flat direction may be inclined. FIG. 3B is inclined so that the angle formed by the flow direction of water when the flow rate is small and the flat direction (indicated by the alternate long and short dash line in the figure) is large. When the flat direction is inclined in this way, the resistance to the swirl flow is further increased. However, you may incline in the reverse direction to FIG.3 (b). That is, you may make it incline so that the angle of the flow direction of water when there is little flow volume and the flat direction may become small. In this case, the swirl flow is gently reduced. Typically, the angle α is 90 degrees (vertical).

  As described above, by causing the support member 60 to act as a baffle plate and preventing the swirling flow, an increase in the flow velocity due to the swirling flow, that is, generation of positive pressure can be prevented. Therefore, air can be reliably sucked into the suction pipe 31 from the hole 62 through the hollow portions of the air pipe 40, the air flow path 44, and the support member 60.

  FIG. 4 is a diagram illustrating an example of the hole 62 formed in the support member 60. 4A shows an example in which one circular hole 62 is formed in one support member 60, FIG. 4B shows an example in which four circular holes 62 are formed side by side in one support member 60, and FIG. Represents an example in which a slit-like hole 62 is formed. The number of the holes 62 may be one, but if a plurality of small holes 62 are arranged in the direction from the connection part 64 of the support member 60 to the suction pipe 31 to the connection part 66 to the bearing housing 52, air is sucked in. Since the liquid 31 is dispersed and sucked, the gas-liquid mixing is uniform, which is preferable. The shape of the hole 62 is arbitrary, but is typically circular because it is easy to form. The size of the hole 62 is determined according to the amount of air to be sucked and the number of holes 62. However, if the hole 62 is made extremely small, the surface tension when sucking air into water is increased, which is not preferable.

  The hole 62 may be formed in a slit shape in a direction from the connection portion 64 of the support member 60 to the suction pipe 31 to the connection portion 66 to the bearing housing 52. In this case, air is dispersed and sucked into the suction pipe 31. Therefore, the gas-liquid mixing is uniform and preferable. The hole 62 is preferably formed above the support member 60 as shown in FIG. By forming upward, the air flowing above the hollow portion of the support member 60 is sucked from the hole 62 when sucking air, and it becomes easy to suck air.

  Further, as shown in FIG. 3, the hole 62 is preferably formed in the downstream direction of the swirling flow of the support member 60. That is, as shown in FIG. 1B, it is formed on the side of the impeller 20 in the rotational direction (arrow direction in the figure). By forming in this way, even if the influence of the swirling flow appears when the flow rate is small, the hole 62 is positioned on the back pressure side of the support member 60, and it is reliably not affected by the positive pressure due to the swirling flow. It becomes possible to inhale. It should be noted that while the flow rate is large, there is almost no influence of the swirling flow, so the hole 62 is not positioned on the back pressure side and does not inhale more than necessary.

  Further, as shown in FIG. 5, the hole 62 may be formed (upward) on the upper surface of the support member 60. FIGS. 5A and 5B are diagrams for explaining a modification of the orientation of the hole 62 formed in the support member 60. FIG. 5A shows the support member 60 having a circular cross section, FIG. 5B shows the support member 60 having an elliptic cross section, (C) shows an example in which a hole (62) is formed upward with respect to the support member 60 having a rectangular (rectangular) cross-sectional shape, and (d) shows a support member 60 with a rounded rectangular cross-sectional shape. Also in FIG. 5, a thick arrow indicates the direction of water flow when the flow rate is high, and a thin arrow indicates the direction of water flow when the flow rate is low. In FIG. 5, the upper part of the drawing corresponds to the actual vertical upper part. As shown in FIG. 5, even if the hole 62 is formed upward with respect to the support member 60 (downstream of the water flow when the flow rate is high), the flow level is low (the water level in the water tank 1 is the lowest). When the water level LWL or lower), the hole 62 becomes negative pressure, and air can be sucked into the suction pipe 31 from the end 41 of the air pipe 40. Further, when the hole 62 is formed upward with respect to the support member 60, particularly when the suction pipe 31 and the support member 60 are integrally formed (for example, the suction pipe 31 and the support member 60 are cast together. When the hole 62 is formed in the support member 60. Note that “the hole 62 is formed upward with respect to the support member 60” is typically a state in which a normal passing through the centroid of the hole 62 in the plan view is a vertical direction. The normal line has an angle with respect to the vertical direction to such an extent that the negative pressure of the hole 62 can be maintained when the water level in 1 is below the minimum water level LWL (to the extent that air can be sucked into the suction pipe 31). It may be in a state.

  As described so far, the rotating shaft 21 is extended to the lower part (upstream side) of the impeller 20, the end 23 thereof is supported by the bearing 50, and the bearing 50 is fixed by the support member 60 (the bearing box 52 is fixed). In the vertical shaft pump 10 in which the hollow portion of the support member 60 communicates with the air pipe 40 and the hole 62 for supplying air into the suction pipe 31 is formed, the rotary shaft 21 or the impeller 20 can rotate stably, and air can be reliably sucked from the hole 62 during operation at a low water level below the minimum water level LWL, thereby avoiding noise and vibration problems. In addition, since the support member 60 also serves as a member for supplying air, the number of members can be reduced, manufacturing complexity and production costs can be reduced, and the flow of water is disposed in the pumping water flow path by the vertical shaft pump 10. The obstructing member can be reduced.

  As shown in FIG. 6, a plurality of the preceding standby operation pumps as described above are usually installed in the machine. FIG. 6 is a partial cross-sectional view illustrating a pump station 101 including three vertical shaft pumps 10 described so far. In the pump station 101, three vertical shaft pumps 10a, 10b, and 10c are installed on the common floor 2. In such a pump station 101, a plurality of vertical shaft pumps 10 are used so as to operate a necessary number according to the amount of incoming water or as a spare.

  The lengths of the water pump casing 33 and the rotary shaft 21 of the plurality of vertical shaft pumps 10 are different, and the heights of the impeller 20 and the suction pipe 31 are different. That is, the lowest water level LWL, the suction start water level SLWL, and the lowest operating water level LLWL of each of the vertical pumps 10a, 10b, and 10c are different. That is, the pumping of each vertical shaft pump 10 is performed with a time difference. For example, at the time of water increase, the vertical pump 10a at the lowest position first starts pumping, and the other vertical pumps 10b and 10c sequentially pump the water. Therefore, it is possible to prevent the water level in the water tank 1 from fluctuating excessively more than the amount of incoming water, and to reduce the load on the power supply equipment.

  Note that the number of vertical pumps 10 provided in the pump station is not limited to three, and an appropriate number of vertical pumps 10 are provided according to the amount of pumped water or the like. In addition, by using a plurality of vertical pumps 10 having the same structure in the lengths of the water pump casing 33 and the rotary shaft 21, the minimum water level LWL, the suction start water level SLWL, and the minimum operating water level LLWL are made different by changing the installation height. It may be.

It is a figure explaining the vertical shaft pump as a 1st embodiment of the present invention, (a) is a section lineblock diagram, and (b) is a bottom view. It is sectional drawing explaining the typical example of the cross-sectional shape of a supporting member, (a) is circular cross-sectional shape, (b) is elliptical cross-sectional shape, (c) is a rectangular (rectangular) cross-sectional shape, (d) is a rounded rectangle A cross-sectional shape is shown. It is a figure explaining the positional relationship of the flow of water and a supporting member, (a) represents the case where the flat direction of the supporting member is made perpendicular, and (b) represents the case where it inclines. It is a figure explaining the example of the hole formed in a supporting member, (a) is an example in which one circular hole is formed in one supporting member, (b) is four circular holes in one supporting member. (C) represents an example in which slit-shaped holes are formed. It is sectional drawing explaining the modification of direction of the hole formed in a supporting member, (a) is a supporting member of circular cross-sectional shape, (b) is a supporting member of elliptical cross-sectional shape, (c) is a rectangle ( (Drawing) shows the example by which the hole was formed in the upper part with respect to the support member of a rectangle section shape with a round (rectangular) section shape. It is a fragmentary sectional view explaining a pump station provided with three vertical shaft pumps. It is sectional drawing explaining the structure of the conventional vertical shaft pump.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water tank 2 Floor 10, 10a, 10b, 10c Vertical shaft pump 20 Impeller 21 Rotating shaft 22a, 22b Bearing 22c Seal 23 Lower end 31 of rotating shaft Suction pipe 32 Liner casing 33 Lifting pipe casing (casing main body)
34 Discharge piping 35 Guide vanes 36 to 39 Flange 40 Air pipe 41 End (other end)
44 Air flow path 50 Bearing 52 Bearing box 60 Support member 62 Hole 64 Connection part with suction pipe 66 Connection part with bearing (box) 90 Flow path 101 Pumping station A1 Water level HWL at the lower end (opening part) of the suction pipe Highest water level LLWL Minimum operating water level LWL Minimum water level SLWL Suction start water level

Claims (7)

A rotation axis arranged vertically and rotating around an axis;
An impeller that is rotated by rotation of the rotating shaft, sucks water and flows upward, and is disposed downstream of the lower end of the rotating shaft;
A suction pipe disposed on the upstream side of the impeller and forming a flow path for flowing the water toward the impeller;
An air pipe having one end connected to the suction pipe and sucking air from the other end;
A bearing disposed upstream of the impeller and rotatably supporting the rotating shaft;
A support member for connecting the suction pipe and the bearing, the support member having a hollow portion communicating with the air pipe and having a hole extending from the outer surface to the hollow portion;
Vertical shaft pump. A cross-sectional shape of the support member is flat;
The vertical shaft pump according to claim 1. A plurality of holes formed in the support member are arranged in a direction from a connection portion with the suction pipe to a connection portion with the bearing;
The vertical shaft pump according to claim 1 or 2. The hole formed in the support member is formed on the rotational direction side of the impeller;
The vertical shaft pump according to any one of claims 1 to 3. The hole formed in the support member has an opening formed upward;
The vertical shaft pump according to any one of claims 1 to 3. The holes formed in the support member were formed at the lowest operating water level;
The vertical shaft pump according to any one of claims 1 to 5. A plurality of vertical shaft pumps according to any one of claims 1 to 6;
The plurality of vertical pumps includes at least two vertical pumps in which the impellers are arranged at different heights;
Pump station.

Images