JP2007023938A - Vertical shaft pump and pump plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vertical shaft pump and a pump plant not easily operating under an air and water mixed condition even if water level drops and not generating large vibration. <P>SOLUTION: The vertical shaft pump is provided with an impeller 20 rotated by a rotary shaft 21 arranged in a vertical direction and sucking water in a water tank 1, a suction pipe 31 arranged in an upstream side of the impeller and forming a flow passage 90 making water flow toward the impeller, an outer casing 60 arranged outside of the suction pipe and forming a flow passage in which water flowing in the suction pipe flows, and an inner pipe arranged inside of the suction pipe and partitioning a flow passage of the suction pipe into an inside 92 of an inner tube and an outside 94 of the inner tube. The pump plant includes at least two vertical shaft pumps is provided with a plurality of the vertical shaft pumps and a water tank 1 having the plurality of the vertical shaft pump installed in, and has the impellers arranged at different height in the plurality of the vertical shaft pumps. <P>COPYRIGHT: (C)2007,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. 11, 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 can be performed even below the minimum operation level LWL of the suction water tank 111. There was a vertical pump 113 that allowed it to continue. 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 lowest operating water level LWL lower than the highest water level HWL, the amount of drainage is gradually reduced by the air flowing in through the holes 115, thereby avoiding a sudden pumping stop due to the lowering of the water level. Even when the water level rises from the water level below the mounting position of 112, the amount of drainage is reduced by the air flowing in through the hole 115 until the water level reaches the minimum operating water level LWL, thereby avoiding the sudden start of pumping. Yes. In such a vertical shaft pump, it is possible to prevent vibration due to the suction vortex being drawn from the suction pipe 14 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. Such a pump is started at a water level LLLWL lower than the lower end of the casing (see, for example, Patent Document 1).
Japanese Utility Model Publication No. 5-33752 (Fig. 1)

  However, in the above-described vertical shaft pump, when the water level becomes the lowest operating water level LWL and the air-water mixing operation is performed, water and air having different specific gravity are mixed and flowed in the vicinity of the impeller, so that the load is unloaded. There is a tendency to increase the vibration of the vertical shaft pump. In particular, when the water level drops and becomes close to the water level LLWL to which the air pipe is attached, high vibration may occur.

  Therefore, an object of the present invention is to provide a vertical shaft pump, a vertical pump system, and a vertical pump station that are unlikely to perform a gas-water mixing operation even when the water level is lowered and do not generate large vibrations.

  In order to achieve the above object, the vertical shaft pump according to the first aspect of the present invention is an impeller that sucks in water in the aquarium 1 by being rotated by a rotary shaft 21 arranged in a vertical direction, for example, as shown in FIG. 20; a suction pipe 31 that forms a flow path 90 that is arranged on the upstream side of the impeller 20 and flows water toward the impeller 20; and water that is arranged outside the suction pipe 31 and flows into the suction pipe 31 An outer casing 60 that forms a flow channel 96; an inner cylinder 50 that is disposed inside the suction pipe 31, and includes a flow path 90 of the suction pipe 31, an inner side 92 of the inner cylinder 50, and an outer side of the inner cylinder 50. And an inner cylinder 50 divided into 94.

With this configuration, when the water level drops and the suction pipe tries to suck water while entraining air while forming a vortex from the water surface, the flow of water flows into the suction pipe from the flow path formed by the outer casing. And components that flow around the outside of the outer casing and flow into the suction pipe. Then, the flow of the two components collides before flowing into the suction pipe, the vortex is disturbed, and the vortex disappears or becomes intermittent. For this reason, vibration due to vortices is less likely to occur.
When the water level further decreases and a backflow occurs in the suction pipe, the backflow flows along the inner wall of the suction pipe, so that it flows through the flow path between the suction pipe and the inner cylinder and flows out of the suction pipe. Therefore, the vortex generated when the suction pipe sucks water is disturbed, and the vortex is eliminated or made intermittent. For this reason, vibration due to vortices hardly occurs.

  Further, in the vertical pump according to claim 2, for example, as shown in FIG. 1, in the vertical pump 10 according to claim 1, the air pipe 40 opens inside the suction pipe 31 (45) and introduces air. May be provided.

  If comprised in this way, when a water level falls further, air will be introduce | transduced in a suction pipe through an air pipe, and a vertical shaft pump can be made to run idly. Therefore, the operation mode can be switched to the idle operation without causing vibration due to air entrainment.

  Moreover, in the vertical shaft pump according to claim 3, for example, as shown in FIG. 1, in the vertical shaft pump according to claim 2, an open / close valve 41 may be provided in the air pipe 40.

  If comprised in this way, when stopping discharge | emission of the water in the water tank in a vertical shaft pump, air can be introduce | transduced in a suction pipe through an air pipe by opening an on-off valve, and a vertical pump can be made to run idly. Therefore, the operation mode can be switched to the idle operation without causing vibration due to air entrainment.

  Further, in the vertical shaft pump according to claim 4, for example, as shown in FIG. 1, in the vertical shaft pump according to claim 3, the opening / closing means 42 for opening and closing the opening / closing valve 41; and the water level L in the water tank 1 is measured. A water level meter 71 for transmitting the water level signal i1; receiving the water level signal i1, and transmitting to the opening / closing means 42 a signal i2 for opening the on-off valve 41 when the water level L drops to a predetermined water level LLWL. The control device 70 may be provided.

  With this configuration, when the water level falls below a predetermined level and it is no longer necessary to drain the water in the tank with the vertical shaft pump, the control device automatically opens the on-off valve and enters the suction pipe through the air pipe. Air can be introduced to allow the vertical shaft pump to run idle. Therefore, it is possible to control the operation mode with high reliability.

  In order to achieve the object, for example, as shown in FIG. 10, the pump station 101 according to the invention according to claim 5 includes a plurality of vertical shafts according to any one of claims 1 to 4. Pumps 10a, 10b, 10c; and a water tank 1 in which a plurality of vertical shaft pumps 10a, 10b, 10c are installed; the plurality of vertical shaft pumps 10a, 10b, 10c have different heights of impellers 20a, 20b, 20c Includes at least two vertical shaft pumps 10a, 10b, 10c.

  If comprised in this way, since a water tank is equipped with the vertical shaft pump from which the water level which starts and finishes water discharge is different, excessive drainage can be prevented and the load with respect to a power supply device can also be reduced.

  According to the present invention, the vertical pump forms a suction pipe that forms a flow path for flowing water toward the impeller, and an outer casing that is disposed outside the suction pipe and forms a flow path for water flowing into the suction pipe. And an inner cylinder that is disposed inside the suction pipe, and includes an inner cylinder that divides the flow path of the suction pipe into an inner cylinder inner side and an inner cylinder outer side, so that even if the water level decreases It is possible to provide a vertical shaft pump that is less susceptible to vibration caused by vortices.

  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. 1 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 which is a part of the vertical shaft pump 10 and related devices. The vertical shaft pump 10 is a pump for preceding standby operation. Pre-standby operation, especially full-speed pre-standby operation, starts the pump in advance before rainwater flows into the suction tank, starts draining as the water level L (Level) rises, and does not stop the pump even if the water level drops Driving at full speed. 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 water pump 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 rotary shaft 21 is arranged in the longitudinal direction (vertical direction) at the center of the casing, and an open-type impeller 20 is attached to the lower end of the rotary shaft 21. 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. A bearing 22c and a seal (not shown) are disposed in the through portion. The rotating shaft is supported at three points by a bearing 22a and the bearing 22c disposed in the vicinity of the impeller 20, and a bearing 22b disposed between the two bearings. In addition, 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 for flowing water through the impeller. The suction pipe 31 is combined with the inner cylinder 50 and the outer casing 60 to have a triple pipe structure. That is, the inner cylinder 50 is arranged inside the suction pipe 31 with a gap from the inner wall of the suction pipe, and the outer casing 60 is arranged outside the suction pipe 31 with a gap from the outer wall of the suction pipe 31. Is placed.

  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. 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.

  The inner cylinder 50 is disposed on the inner side of the suction pipe 31 and forms a first flow path 92 on the inner side, and on the outer side, a space having a substantially uniform gap with the suction pipe 31, that is, a second It is a substantially cylindrical member that forms the flow path 94. Here, the substantially cylindrical shape includes a shape in which the lower end expands in accordance with the shape of the suction pipe 31, and even if the cross section is polygonal, the first flow path 92, the first flow direction from all directions. 2 includes a shape in which the wall of the inner cylinder is distributed at a distance from the uniform central axis (extension line of the rotating shaft 21) to the extent that water is sucked into the second flow path 94. The inner cylinder 50 is fixed to the suction pipe 31 by a rib 51 disposed between the suction pipe 31 and the inner cylinder 50. The rib 51 is a flat plate whose surface is perpendicular to the circumferential direction of the inner cylinder 50, and is joined to the suction pipe 31 and the inner cylinder 50 on the downstream side from the portion where the diameter of the suction pipe 31 and the inner cylinder 50 is increased. . The suction pipe 31 and the inner cylinder 50 may be joined at a location where the diameter is increased, but if the suction pipe 31 and the inner cylinder 50 are joined at a downstream side from the location where the diameter is increased, a rib 51 having a simple shape such as a rectangle or a trapezoid. It is possible to fix with. Alternatively, if the ribs 51 are provided up to the upstream diameter increasing portion, the bonding strength is improved. A plurality of ribs 51 are arranged at equal intervals, for example, 4 to 8 ribs.

  As shown in the partial cross-sectional view of FIG. 2, the inner cylinder 50 may be supported by the support bases 53 and 54 from the bottom of the water tank 1 without being fixed to the suction pipe 31 by the ribs. The support bases 53 and 54 are composed of several pillars 53 or plates held by a base 54 installed at the bottom of the water tank. In the case of a cylindrical plate, a large number of holes are formed to ensure a flow path through which water flows. The lower portion of the cylinder 50 is supported by support bases 53 and 54. The method of supporting the cylinder 50 is not limited to the above, and may be supported by other methods. The cylinder 50 is disposed at a predetermined position of the suction pipe 31 and a flow path of water sucked into the cylinder 50 is secured. It may be supported in any way.

  The outer casing 60 is a member that covers the outer periphery of the suction pipe 31 and forms a space having a substantially uniform gap with the suction pipe 31, that is, a third flow path 96. It is preferable that the lower end (or outer edge) of the outer casing 60 has substantially the same diameter as the lower end (outer edge) of the suction pipe 31 or a slightly larger diameter. The slightly larger diameter means a range in which a vortex passes if the water surface is lowered and a vortex from the water surface is formed when the suction pipe 31 sucks water. The outer casing 60 is fixed to the suction pipe by a rib 61 disposed between the suction pipe 31 and the outer casing 60. The rib 61 is a flat plate whose surface is perpendicular to the circumferential direction of the suction pipe 31. A plurality of ribs 61, for example, 4 to 8 ribs 61 are arranged at equal intervals.

  An air pipe 40 is connected to the inner cylinder 50 and has an opening 45 at a height A3 on the inner surface of the inner cylinder 50. The air pipe 40 penetrates the suction pipe 31, and also penetrates the outer casing 60 depending on the shape of the outer casing 60. An opening 46 is provided in the atmosphere. That is, the opening 45 on the inner surface of the inner cylinder 50 communicates with the opening 46 in the atmosphere. The opening 46 in the atmosphere does not necessarily have to be above the floor 2 and may be above the water level LLWL that stops the suction of the vertical shaft pump 10 described later. The opening 46 is preferably above the LWL. Further, if the opening 46 is disposed above the water surface in the water tank 1 below the floor 2, it is preferable that no strange odor is released onto the floor 2 even if the water is dirty water. The air pipe 40 is provided with an on-off valve 41 and can block communication between the opening 45 on the inner surface of the inner cylinder 50 and the opening 46 in the atmosphere. The on-off valve 41 may be of any type as long as it can seal the air flow, such as a gate valve or a needle valve. The on-off valve 41 is preferably disposed outside the water tank 1 because it is easier to operate and maintain. In FIG. 1, the vertical shaft pump 10 is illustrated as having one air pipe 40, but the number of the air pipes 40 may be two or more. It is suitable because it is sent in.

  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 L 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, it is a water level below which air starts to be sucked in from the lower end of the suction pipe 31. In the present embodiment, the suction pipe 31 is combined with the inner cylinder 50 and the outer casing 60 to form a triple pipe structure, but the LWL does not include the inner cylinder 50 and the outer casing 60 but includes only the suction pipe 31. In addition, it is a water level that forms a vortex from the surface of the water and starts to suck air. However, the 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. Normally, there is a water level LLWL that stops suction of water from the vertical shaft pump 10 at a position lower than the suction start water level SLWL. Below the water level LLWL, there are a water level A1 at the lower end (opening) of the suction pipe 31 and a water level A2 at the lower end (opening) of the inner cylinder 50.

  Next, the operation of the vertical shaft pump 10 will be described with reference to FIG. First, the vertical shaft pump 10 is started in a state where the water level is lower than A2. 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 A2. This is the start of the preceding standby operation. At this time, the on-off valve 41 is closed.

  The water level L in the water tank rises due to the inflow of rainwater and exceeds the lower end water level A2 of the suction bell. Even if the water level exceeds the water level A1 or exceeds the water level LLWL, water is not yet sucked up. The impeller 20 is idling. When the water level L further rises and reaches the water level SLWL, the impeller 20 starts to suck water. When water suction starts, the distance between the water surface and the lower end of the suction pipe 31 is short, and a vortex tends to be formed from the water surface. That is, the suction pipe 31 tries to suck in water while entraining air by a vortex from the water surface.

  However, as shown in the partial cross-sectional view around the suction pipe 31 in FIG. 3, the vertical pump 10 is provided with the outer casing 60, so that water sucked into the suction pipe 31 is water that flows outside the outer casing 60. 82 and water 84 flowing through the third flow path 96, and collide near the lower end of the suction pipe 31. Therefore, even if a vortex is formed, it disappears or becomes an intermittent vortex. Therefore, the vibration of the vertical pump 10 caused by the entrainment of air for the vortex is suppressed.

  Furthermore, the water level rises to a water level between the water level LWL and the water level HWL, and the pump 10 continues the steady operation. Thereafter, the water level L is lowered due to the drainage of the pump 10, and when the water level LWL falls below the water level LWL, for example, the distance between the water surface and the lower end of the suction pipe 31 is shortened. Try to. However, as described above, even if a vortex is formed, it disappears or becomes an intermittent vortex. Therefore, the vibration of the vertical pump 10 caused by the entrainment of air for the vortex is suppressed.

  As shown in the partial cross-sectional view around the suction pipe 31 in FIG. 4A, the rib 63 may be extended upward along the suction pipe 31. When such a rib 63 is provided, the effect | action which rectifies the water 84 which flows through the 3rd flow path 96 increases, and the effect which suppresses generation | occurrence | production of a vortex increases.

  Alternatively, as shown in the partial cross-sectional view around the suction pipe 31 in FIG. 4B, the outer casing 65 is not made to have a substantially uniform gap with the suction pipe 31, but the outer casing 65 is connected to the suction pipe 31. You may form in the shape of a horizontal disk arrange | positioned outside. By providing the outer casing 65, a third flow path 96 is formed between the inner edge of the outer casing 65 and the outer periphery of the suction pipe 31, and water from the upper side (that is, vortex is mainly sucked into the suction pipe 31). The generated water is divided into water 82 that flows outside the outer casing 65 and water 84 that flows through the third flow path 96, and collides near the lower end of the suction pipe 31. Therefore, even if a vortex is formed, it disappears or becomes an intermittent vortex. Therefore, the vibration of the vertical pump 10 caused by the entrainment of air for the vortex is suppressed.

  Returning to FIG. 1, the description of the operation of the vertical shaft pump 10 will be continued. When the water level L further decreases, a back flow occurs in the vertical shaft pump 10. That is, not all the water is sent to the discharge side by the impeller 20, but a part of the water flows down to the upstream side.

  This backflow will be described with reference to a QH curve representing the characteristics of the pump shown in FIG. FIG. 5 is a graph showing the performance of the full-speed advance standby operation pump, with the vertical axis indicating the total lift H (%) and the horizontal axis indicating the discharge amount Q (%). In FIG. 5, curve A represents a flow rate-lift (QH) curve, curve B represents a resistance curve at the planned lift (straight line C), and curve D represents a resistance curve at the maximum actual lift (straight line E). . The state of curve D is when the discharge pressure is high.

  In the advanced standby operation pump for rainwater drainage, the height of drainage to the river or sea to be drained generally does not change much. However, at least the water level in the water tank 1 changes from A2 or lower to HWL. Although FIG. 1 shows a case where the height difference between A2 and HWL is not so large, the casing body 33 can actually be made longer and may exceed, for example, 10 m. In such a preceding standby operation pump, when the water level L becomes low, the resistance curve becomes a curve D. That is, in the preceding standby operation pump as described above, since there is a head difference of 10 m between the planned head and the maximum actual head, an operation state in which the flow rate is inevitably small as indicated by the point B occurs.

  The point A in the figure indicates the operating point at the planned actual head. At this time, the water in the suction pipe 31 flows uniformly toward the impeller 20 in the axial direction. Point B in the figure indicates the operating point at the maximum actual head, which is an operating point on the small water volume side with respect to the maximum efficiency point. In the operation of this small amount of water, a reverse flow is generated in the impeller 20. Since the reverse flow has a swirling component that rotates in the rotational direction of the impeller 20, the reverse flow is generated in the outer periphery of the suction pipe 31, that is, in the vicinity of the inner wall of the suction pipe 31. When the operation is performed in a range where the water level L is low, such a backflow is generated, and when the head becomes large, the backflow becomes so large that it cannot be ignored.

  As shown in the partial cross-sectional view around the suction pipe 31 in FIG. 6, the backward flow 86 having the swirl component is guided to the second flow path 94 when flowing backward in the suction pipe 31. Therefore, when the reverse flow 86 passes through the second flow path 94, the rib 51 is prevented from moving in the swirl direction, and as a reverse flow 88 having no swirl component, the suction pipe 31 passes through the second flow path 94. It flows out. Increasing the length of the rib 51 to the location where the suction pipe 31 and the inner cylinder 50 are expanded increases the effect of suppressing the swirling component of the backflow 86 in addition to increasing the bonding strength. Since the back flow 88 flowing out from the second flow path 94 does not have a swirl component, when the inner cylinder 50 sucks water, the back flow 88 disturbs the flow field around the inner cylinder 50 and vortices are less likely to occur. .

  In addition, as shown in FIG. 7, the ribs 52 that support the inner cylinder 50 may be disposed obliquely along the direction in which the backflow 89 flows instead of being perpendicular to the circumferential direction of the inner cylinder 50. FIG. 7A is a partial cross-sectional view around the suction pipe 31, and FIG. 7B is a perspective view of the rib 52 and the inner cylinder 50 as viewed in the X direction shown in FIG. By arranging the ribs along the flow of the back flow 89 in this way, the flow rate of the back flow 89 is not reduced and flows out from the second flow path 94 while maintaining the flow rate. The power that disturbs the field increases. Therefore, the generation of vortices can be suppressed. As shown in FIG. 2, the same effect can be obtained even when no rib is provided.

  Even when the inner cylinder 50 sucks in water and tries to suck in water while entraining air by a vortex from the water surface, the water 82 flowing outside the outer casing 60 and the water flowing in the third flow path 96 are also shown. 84 collides with the backflow 88 flowing out from the second flow path 94. Therefore, even if a vortex is formed, it disappears or becomes an intermittent vortex. Therefore, the vibration of the vertical pump 10 caused by the entrainment of air for the vortex is suppressed.

  As shown in the partial cross-sectional view around the suction pipe 31 in FIG. 8, the lower end of the inner cylinder 55 may be formed as the same height as the lower end of the suction pipe 31 or may be shorter and higher than the lower end of the suction pipe 31. The lower end of the inner cylinder 55 may be formed on the (downstream side). Even in such a configuration, the inner cylinder 55 caused by the backflows 88 and 89 disturbs the flow field to suck water and suppresses the generation of the vortex, and the backflow 88 flowing out from the second flow path 94 is also generated. By colliding with the water 82 flowing outside the outer casing 60 and the water 84 flowing through the third flow path 96, the vortex is eliminated or intermittent, and the vertical pump 10 generated by the entrainment of air for the vortex. The effect of suppressing the vibration is obtained.

Returning to FIG. 1, the description of the operation of the vertical shaft pump 10 will be continued. Further, when the water level L becomes low and near the water level LLWL, the suction of water is stopped. For this purpose, air is introduced into the inner cylinder 50 through the air pipe 40 by opening the on-off valve 41. Pressure at the position of the opening 45 of the inner surface of the inner cylinder ^{50, (L-A3) - (} v 2 / 2g); L = level, A3 = height of the opening 45, v = velocity, at g = gravitational acceleration Yes, if the difference between the water level L and the height A3 of the opening 45 is reduced, a negative pressure is obtained. Therefore, it is preferable that the height A3 of the opening 45 in the inner tube 50 of the air pipe 60 is set equal to or above the water level LLWL. When the pressure at the position of the opening 45 becomes a negative pressure, the on-off valve 41 is opened, whereby air flows into the inner cylinder 50 from the opening 45. If there is a swirl component in the water flow, a positive pressure is generated due to the centrifugal force due to the swirl component, and it becomes difficult for air to flow in. However, as described with reference to FIG. Since it is guided to the flow path 94, there is no swirl component in the first flow path 92 inside the inner cylinder 50. When air flows into the inner cylinder 50, the inside of the suction pipe 31 is filled with air, the suction of water disappears, and the impeller 20 enters an idle operation state in which it is operated in the air. That is, the pump 10 is in an air lock state in which no water is sucked.

  Alternatively, the opening 45 may be formed not inside the inner cylinder 50 but inside the suction pipe 31. At that time, as described above, because of the centrifugal force due to the swirling component of the reverse flow, the pressure at the opening position is unlikely to become negative pressure, so it is preferable to increase the installation height A3 of the opening. In any case, the installation position A3 of the opening is installed below (upstream) from the SLWL.

  As shown in FIG. 9, in the vertical shaft pump 12, the air pipe 40 may not include an on-off valve. Since air flows in when the opening 45 becomes negative pressure, the impeller 20 is in an idling state in which it is operated in the air. That is, the pump 10 is in an air lock state in which no water is sucked. In this case, the opening 46 of the air pipe 40 only needs to be above the water level LLWL. However, since water is also sucked through the air pipe 40, particularly when the water is sewage, in order to avoid clogging with dust or the like. It is preferable to set it above HWL. Moreover, if it arrange | positions in the water tank 1 below the floor 2, a strange odor will not be discharge | released on the floor 2, but it is suitable.

  In this way, the impeller 20 continues the idling state in the air. When it continues to rain, the operation is continued, the water level L rises again, and the pump 10 starts to suck water when it reaches the water level SLWL as described above. In this manner, the preceding standby operation pump 10 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.

  Next, the vertical shaft pump 100 will be described with reference to FIG. The vertical shaft pump 100 includes an actuator 42 as a means for opening and closing the on-off valve 41, a water level meter 71 for measuring the water level L, and a control device 70 for controlling opening and closing of the on-off valve based on the water level L. It is a vertical shaft pump provided.

  The water level meter 71 measures the water level and transmits a water level signal i1 indicating the measured water level. In the vertical shaft pump 100 of FIG. 1, the water level signal i1 is transmitted through the cable 72, but the water level signal i1 may be a radio signal. The water level signal i1 transmitted from the water level gauge 71 is received by the control device 70.

  The control device 70 determines whether the on-off valve 41 is opened or closed based on the water level signal i1. The control device 70 may be a large computer as a control device that also controls the operation of other devices, or may be a personal computer or a microcomputer that controls only the operation of the vertical shaft pump 10. The control device 70 controls the on-off valve 41 so that it opens only when the vertical pump 10 is discharging water and the water level L is lowered to the water level LLWL, and is closed in other cases. Therefore, it is preferable that the control device 70 obtains information on the operating state of the vertical shaft pump 10. The information on the operating state may be obtained as the discharge amount of the vertical shaft pump 10, or may be obtained as a history of opening / closing of the on-off valve 41 and the water level L, or may be obtained from other information. The opening / closing of the opening / closing valve 41 determined by the control device 70 is transmitted to the actuator 42 as an opening / closing signal i2. In the vertical shaft pump 100 of FIG. 1, the open / close signal i2 is transmitted through the cable 73, but the open / close signal i2 may be a radio signal. The opening / closing signal i <b> 2 transmitted from the control device 70 is received by the actuator 42.

  The actuator 42 opens and closes the opening / closing valve 41 in accordance with the opening / closing signal i2. The actuator 42 may be a solenoid, a motor, or other power.

  In FIG. 1, the control device 70 is illustrated as being provided separately from the water level gauge 71 or the actuator 42, but the control device 70 may be provided as a part of the water level gauge 71 or a part of the actuator 42. You may comprise as. If comprised in this way, transmission / reception of the water level signal i1 or the opening / closing signal i2 will become easy.

  In the vertical shaft pump 100, the inflow of air into the vertical shaft pump 10 by opening and closing of the on-off valve 41, that is, switching to the idle operation is automatically performed based on the water level L, so that the reliability of operation mode control is improved, In addition, the labor of the operator can be reduced.

  Next, with reference to the block diagram of FIG. 10, the pump station 101 which is the 2nd Embodiment of this invention is demonstrated. In the pump station 101, three vertical shaft pumps 10 a, 10 b, and 10 c are installed on a common floor 2 of one water tank 1. The lengths of the pump pipe casings 33a, 33b, 33c and the rotary shafts 21a, 21b, 21c of the three vertical shaft pumps 10a, 10b, 10c are different, and the impellers 20a, 20b, 20c are arranged at different heights. Yes. Therefore, as described with reference to FIG. 1, the water level LWL, SLWL, LLWL, A1, A2 and the opening height A3 of the inner surface of the inner cylinder of the air pipe, which are specific to each vertical pump 10a, 10b, 10c. Are different. About another structure, each vertical pump 10a, 10b, 10c may be the same structure.

  As described above, by providing the three vertical shaft pumps 10a, 10b, and 10c, the pump station 101 performs the following operation. When the water increases, the lowest vertical shaft pump 10a of the impeller 20a first starts operation. If the increase in water continues even after discharging by the vertical pump 10a, the impeller 20b starts to operate the next lower vertical pump 10b. If the increase in water continues even after discharging by the vertical pumps 10a and 10b, the operation of the vertical pump 10c with the high impeller 20c is started. Further, at the time of water reduction, if the water level L becomes the water level LLWL (see FIG. 1) of the vertical pump 10c with the high impeller 20c, the vertical pump 10c is set to the idle operation, and if water reduction continues, the vertical pump 10c You may stop idling. When the water level is further reduced and the water level L reaches the water level LLWL of the vertical pump 10b with the next highest impeller 20b, the vertical pump 10b is idled. If the water level continues to decline, the vertical pump 10b is idled. You may stop. If the water level is further reduced and the water level L becomes the water level LLWL of the vertical pump 10a with the impeller 20a being low, the vertical pump 10a is idled. If the water level continues to be reduced, the idle pump of the vertical pump 10a is stopped. Also good.

  As described above, according to the water level L, the operation of the three vertical pumps 10a, 10b, and 10c can be started and ended sequentially in the pump station 101. To prevent the water level in the water tank 1 from fluctuating up and down, and the load on the power supply equipment can be reduced.

  The pump station 101 includes three vertical shaft pumps 10a, 10b, and 10c, but the number of vertical pumps is not limited to three. Moreover, it is not necessary for the height of the impellers of all the vertical shafts to be different, and a plurality of vertical shaft pumps having impellers at the same height and vertical pumps having impellers having different heights may be provided. . Although the pump pipe casing and the rotary shaft have been described as having different lengths, the height of the impeller can be changed by changing the height (floor height) of the vertical shaft pump having the same length of the pump pipe casing and the rotary shaft. It is possible to install a plurality of vertical pumps by changing the length. Moreover, in FIG. 10, although the lower end of the suction pipe is shown as having a different height, it may be configured to have the same height.

  When the vertical pump 100 described above is used in a pump station, a plurality of vertical pumps 100 may each be provided with a control device. However, as shown in FIG. The water level signal i1 may be received, and the opening / closing valves 41a, 41b, 41c of all the vertical shaft pumps may be controlled. If comprised in this way, the number of control apparatuses can be reduced.

It is a section lineblock diagram explaining a vertical shaft pump as a 1st embodiment of the present invention. It is a fragmentary sectional view around the suction pipe of a vertical shaft explaining the modification of an inner cylinder. It is a fragmentary sectional view around the suction pipe of a vertical shaft explaining the flow of water around an outer casing. It is a fragmentary sectional view around the suction pipe of a vertical shaft pump explaining the modification of an outer casing. (A) is the modification which extended | stretched the rib, (b) is the modification which formed the outer casing in the shape of a horizontal disk. It is a QH curve explaining the characteristic of a vertical shaft pump. It is a fragmentary sectional view around the suction pipe of a vertical shaft explaining the flow of the backflow from a vertical pump. It is a figure explaining the rib modification which supports an inner cylinder, (a) is a fragmentary sectional view around the suction pipe of a vertical shaft pump, (b) is a partial side view seen from the arrow X in (a) which shows a rib and an inner cylinder. It is. It is a fragmentary sectional view around the suction pipe of a vertical shaft explaining the modification of an inner cylinder. It is a section lineblock diagram explaining a modification of a vertical shaft pump as a 1st embodiment of the present invention. It is a block diagram explaining the structure of the pump station as the 2nd Embodiment of this invention. It is sectional drawing explaining the structure of the conventional vertical shaft pump.

Explanation of symbols

1 Water tank 2 Floor 10, 10a to 10c, 12, 100 Vertical shaft pump 20, 20a to 20e Impeller 21, 21a to 21e Rotary shaft 22a, 22b, 22c Bearing 31, 31a, 31d, 31e Suction pipe 32 Liner casing 33, 33a , 33b, 33c Pumping pipe casing (casing body)
34 Discharge piping 35 Guide vanes 36-39 Flange 40, 40a Air pipe 41, 41a-41c Open / close valve 42, 42a Actuator (open / close means)
45, 46 Opening 50, 55 Inner cylinder 51, 52 Rib 60, 65 Outer casing 61, 63, 66 Rib 70, 75 Controller 71 Water level gauge 82, 84 Water flow 86 Back flow 88, 89 Back flow 90 due to swirl Flow path 92 First flow path 94 Second flow path 96 Third flow path 101 Pump machine field i1 Water level signal i2 Open / close signal (signal for opening the open / close valve)
L water level

Claims (5)

An impeller that is rotated by a rotating shaft arranged in the vertical direction and sucks water in the water tank;
A suction pipe disposed on the upstream side of the impeller and forming a flow path for flowing the water toward the impeller;
An outer casing which is disposed outside the suction pipe and forms a flow path through which water flowing into the suction pipe flows;
An inner cylinder disposed inside the suction pipe, the inner cylinder separating the flow path of the suction pipe into an inner side of the inner cylinder and an outer side of the inner cylinder;
Vertical shaft pump. An air pipe that opens inside the suction pipe and introduces air;
The vertical shaft pump according to claim 1. An open / close valve is disposed in the air pipe;
The vertical shaft pump according to claim 2. Opening and closing means for opening and closing the opening and closing valve;
A water level meter that measures the water level in the water tank and transmits a water level signal;
A control device that receives the water level signal and transmits a signal for opening the on-off valve to the on-off means when the water level falls to a predetermined water level;
The vertical shaft pump according to claim 3. A plurality of vertical pumps according to any one of claims 1 to 4;
A water tank in which the plurality of vertical shaft pumps are installed;
The plurality of vertical pumps includes at least two vertical pumps in which the impellers are arranged at different heights;
Pump station.

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