JP2024082994A - pump - Google Patents

Abstract

[Problem] To provide a pump that can improve pump performance when minimum flow is executed. [Solution] A pump 10 includes a cylindrical water lifting pipe 21, an impeller 33 that can rotate around the axis A of the water lifting pipe 21, and a rotor 40 that is arranged below the impeller 33 of the water lifting pipe 21 and can rotate around the axis A. The rotor 40 has a plurality of blades 41 that protrude radially, and at least one upper end of the plurality of blades 41 protrudes into the water lifting pipe 21, and rotates following the pre-swirl flow RF of the water lifted below the impeller 33 caused by the rotation of the impeller 33. [Selected Figure] Figure 2

Description

The present invention relates to a pump.

Patent Document 1 discloses a pump in which a vortex suppressing member is arranged at the bottom end of the casing to suppress the generation of air suction vortices and underwater vortices. The vortex suppressing member has multiple rotating plates extending radially, and can rotate following the water flow sucked in from the suction port by the rotation of the impeller. The rotation of this vortex suppressing member destroys air suction vortices in which air on the water surface is sucked into the water flow extending from the water surface to the suction port, and underwater vortices in which gas (bubbles) due to cavitation is mixed into the water flow extending from the bottom of the suction tank to the suction port, suppressing the intrusion of gas into the casing. The direction in which the vortex suppressing member rotates depends on the pump discharge volume (i.e., the amount of suction into the casing) and the water flow in the suction tank (outside the casing), and this water flow depends on the shape and suction volume of the suction tank, regardless of the direction and speed of rotation of the impeller.

JP 2020-193604 A

In the pump of Patent Document 1, no consideration is given to pump performance. Therefore, when minimum flow (managed operation) is performed, in which the flow rate ratio to the optimal flow rate is lower than the maximum efficiency point, the shaft power increases and pump performance may decrease. Therefore, there is room for improvement in the pump performance when minimum flow is performed in the pump of Patent Document 1.

The objective of the present invention is to provide a pump that can improve pump performance when minimum flow is being executed.

The pumped water sucked into the pump casing by the rotation of the impeller is discharged while swirling in the circumferential direction around the axis of the pumping pipe. Of this swirling flow of pumped water, the pre-swirling flow below the impeller (upstream side) roughly swirls in the opposite direction to the rotation of the impeller when the flow rate ratio to the optimal flow rate is higher than the maximum efficiency point, swirls in the same direction as the rotation of the impeller when the flow rate ratio is lower than the maximum efficiency point, and does not occur (no swirling) when the flow rate ratio is near the maximum efficiency point. On the other hand, the theoretical head of the pump can be calculated using Euler's formula, and the faster the flow rate of the pre-swirling flow in the same direction as the rotation of the impeller, the lower the pump head and shaft power can be kept. The present invention was made based on such knowledge.

One aspect of the present invention provides a pump comprising a cylindrical water lift pipe extending vertically, an impeller disposed at the lower part of the water lift pipe and rotatable around the axis of the water lift pipe, and a rotor having a plurality of radially protruding blades, disposed below the impeller on the water lift pipe and rotatable around the axis, wherein the rotor has an upper end of at least one of the plurality of blades protruding into the water lift pipe and rotates following the pre-swirl flow of the water lifted below the impeller caused by the rotation of the impeller.

The pump is equipped with a rotor that has multiple blades below (upstream of) the impeller, at least one of which has an upper end protruding into the lift pipe, and rotates following the pre-swirling flow of the lift water caused by the rotation of the impeller. In other words, the rotor rotates due to the pre-swirling flow in the lift pipe, not the water flow in the suction tank. As a result, when the flow rate ratio to the optimal flow rate is higher than the maximum efficiency point, the rotor rotates in the opposite direction to the direction in which the impeller rotates due to the pre-swirling flow, and when the flow rate ratio is lower than the maximum efficiency point, the rotor rotates in the same direction as the impeller rotates due to the pre-swirling flow. When the flow rate ratio is near the maximum efficiency point, the rotor does not rotate due to the pre-swirling flow.

In this pump, when minimum flow is performed, where the flow rate is lower than the maximum efficiency point, the decrease in the speed of the pre-swirling flow can be suppressed compared to when non-rotatable vanes are arranged. As a result, the speed difference between the pre-swirling flow and the swirling flow above the impeller (downstream side) can be reduced, so that the shaft power at minimum flow can be reduced and the pump performance can be improved. In addition, the rotation of multiple vanes can destroy the air suction vortex in which air above the water surface is sucked into the water flow extending from the water surface to the suction port, and the underwater vortex in which gas (bubbles) due to cavitation are mixed into the water flow extending from the bottom of the suction tank to the suction port, suppressing the intrusion of gas into the lift pipe.

The pump of the present invention can improve pump performance when minimum flow is being performed.

1 is a cross-sectional view of a vertical pump according to a first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of part II in FIG. 1 . FIG. 2 is a bottom view of the vertical pump of FIG. 1 . IV-IV line end view of FIG. 1. 1 is a graph showing the relationship between the fluid force acting on the blade and the rotation speed of the blade. Graph showing changes in pump performance. FIG. 4 is a cross-sectional view similar to FIG. 2 of a vertical pump according to a second embodiment. FIG. 11 is a cross-sectional view similar to FIG. 2 of a vertical pump according to a third embodiment. FIG. 9 is a bottom view of the vertical pump of FIG. 8 . FIG. 11 is a cross-sectional view similar to FIG. 2 of a vertical pump according to a fourth embodiment. FIG. 11 is a cross-sectional view similar to FIG. 2 of a vertical pump according to a fifth embodiment. FIG. 12 is an enlarged cross-sectional view of part XII of FIG. 11 . FIG. 13 is a cross-sectional view similar to FIG. 2 of a vertical pump according to a sixth embodiment. FIG. 13 is a cross-sectional view similar to FIG. 2 of a vertical pump according to a seventh embodiment. FIG. 13 is a cross-sectional view similar to FIG. 2 of a vertical pump according to an eighth embodiment.

The following describes an embodiment of the present invention with reference to the drawings.

First Embodiment
Referring to FIG. 1, a vertical pump 10 according to a first embodiment of the present invention is fixed to an installation floor 1 of a drainage pumping station, and discharges rainwater, etc. that has flowed into a suction tank 2 below the installation floor 1 downstream.

The vertical shaft pump 10 includes a pump casing 20, a rotating shaft 30, an impeller 33, a motor 38, and a control unit (not shown), and the control unit can perform normal operation for the purpose of drainage and management operation for the purpose of not drainage. The management operation is performed for the purpose of maintaining the performance of the vertical shaft pump 10, for example, when normal operation is not performed for a long period of time. In this management operation, the motor 38 is rotated at a slower speed than during normal operation so that the discharge volume is minimized, and the impeller 33 is rotated at a lower speed than during normal operation. This management operation includes a minimum flow operation performed with the gate valve 6 interposed in the discharge pipe 5 in an open state, and a shutoff operation performed with the gate valve 6 in a closed state. For example, the gate valve 6 is a manual valve that can be manually switched between an open state and a closed state.

In the vertical pump 10 of this embodiment, in order to reduce the shaft power during minimum flow and improve pump performance, a rotor 40 that can be rotated by the pre-swirl flow RF in the pump casing 20 is provided below the impeller 33 of the pump casing 20. In addition, the rotation of this rotor 40 destroys the air suction vortex SV and the underwater vortex UV shown in Figure 2, suppressing the intrusion of gas into the pump casing 20.

The configuration of the pump casing 20, the rotating shaft 30, the impeller 33, the motor 38, and the rotating body 40 will be described in detail below.

Referring to FIG. 1, the pump casing 20 is generally cylindrical and includes a pumping pipe 21 disposed in the suction tank 2 and a discharge elbow 27 disposed on the installation floor 1.

The lift pipe 21 hangs down from the installation floor 1 into the suction tank 2 and extends vertically. The lift pipe 21 comprises a lift pipe body 22, a vane case 23, and a bell mouth 24, which are bolted together in this order from top to bottom.

The water lift pipe body 22 is a straight pipe, and the total length of the water lift pipe 21 can be changed by changing the total length or the number.

The vane case 23 is elliptical cylindrical and has a bearing casing 26 attached to its inside via multiple guide vanes 25.

Referring to FIG. 2, the bellmouth 24 is generally cylindrical and includes a joint 24a and a bellmouth body 24b that are integrally formed. The joint 24a is bolted to the vane case 23 and gradually reduces in diameter from the top end downward. The bellmouth body 24b is connected to the bottom end of the joint 24a and gradually widens downward. The bottom end of this bellmouth body 24b is an intake port 24c that draws in water from the suction tank 2, and is disposed at a set distance from the bottom 3 of the suction tank 2. However, the joint 24a and the bellmouth body 24b may be provided separately. In this case, the bellmouth body 24b is referred to as the bellmouth 24.

Referring to FIG. 1, the discharge elbow 27 is a bent pipe with an axis curved at 90 degrees. One end of the discharge elbow 27 is joined to the upper end of the lift pipe 21, and the other end of the discharge elbow 27 is joined to the discharge pipe 5. A base plate 28 is provided at the bottom of the discharge elbow 27 for fixing to the installation floor 1. However, the base plate 28 may also be provided at the top of the lift pipe main body 22.

The rotating shaft 30 passes through the discharge elbow 27 and is arranged along the axis A of the lift pipe 21, and is rotatably supported by an underwater bearing arranged inside the lift pipe 21. The lower end of the rotating shaft 30 passes through the bearing casing 26 and protrudes toward the suction port 24c.

Referring to FIG. 2, the impeller 33 is disposed below the bearing casing 26, which is the lower part of the lift pipe 21, and is attached to the rotating shaft 30. This impeller 33 includes a hub 34 for fastening to the rotating shaft 30, and a number of blades 35 protruding radially from the hub 34.

Referring to FIG. 1, the motor (drive source) 38 is mechanically connected to the upper end of the rotating shaft 30 located outside the pump casing 20. The motor 38 is electrically connected to a drive circuit (not shown), and a control unit electrically connected to this drive circuit causes the impeller 33 to rotate at a predetermined rotation speed around the axis A of the lift pipe 21 in the direction R shown by the arrow in FIG. 2 via the rotating shaft 30.

Referring to FIG. 2, the rotation of the impeller 33 draws water from the suction tank 2 into the pump casing 20 through the suction port 24c. This pumped water is discharged downstream while swirling circumferentially around the axis A of the pumping pipe 21. Above the impeller 33 (downstream), the pumped water swirls in the same direction as the direction R in which the impeller 33 rotates. Below the impeller 33 (upstream), the swirling direction of the pumped water changes depending on the rotation speed of the impeller 33 driven by the motor 38. The swirling direction of this pre-swirling flow RF is as follows:

In the excessive flow rate region shown in FIG. 6, where the flow rate ratio Q/Qopt to the optimal flow rate Qopt is higher than the highest point of efficiency η (maximum efficiency point), the pre-swirling flow RF swirls in the opposite direction f1 to the direction R in which the impeller 33 rotates. In the partial flow rate region shown in FIG. 6, where the flow rate ratio Q/Qopt is lower than the maximum efficiency point, the pre-swirling flow RF swirls in the same direction f2 as the direction R in which the impeller 33 rotates. In the rated operation region (near the maximum efficiency point) between the excessive flow rate region and the partial flow rate region shown in FIG. 6, the pre-swirling flow RF does not occur (no swirl).

The rotor 40 is provided in the pump casing 20 so as to rotate around the axis A of the lift pipe 21 by the pre-swirling flow RF of the lifted water. Specifically, the rotor 40 has a plurality of radially protruding vanes 41, is disposed below the impeller 33 of the lift pipe 21, and rotates following the pre-swirling flow RF in the lift pipe 21. Referring to Figures 2 and 3, the rotor 40 of this embodiment has vanes 41 integrally provided on the inner bellmouth (inner cylinder member) 42, and is rotatably attached to a shaft 43 protruding downward from the impeller 33.

The shaft portion 43 is formed by an extension of the rotating shaft 30. With reference to Figures 2 and 4, the shaft portion 43 extends along the axis A of the lift pipe 21. The shaft portion 43 is rotatably supported by an underwater bearing 47 in a holder 48 provided in the bellmouth 24 via a guide vane 48a. A bolt shaft portion 43a is provided at the lower end of the shaft portion 43 to support the rotor 40 in cooperation with a support plate 45 and a nut 46, which will be described in detail later. However, the shaft portion 43 may be provided on the hub 34 of the impeller 33 as long as it extends along the axis A of the lift pipe 21. It is preferable that the guide vane 48a is inclined so as to promote a pre-swirling flow RF in the same direction f2 as the direction R in which the impeller 33 rotates.

Referring to Figures 2 and 3, the inner bellmouth 42 is generally conical and cylindrical, with an upper portion 42a of uniform diameter and a lower portion 42b that gradually widens as it moves downward from the upper portion 42a. A pair of underwater bearings 44 that slide against the shaft portion 43 are attached to the inside of the inner bellmouth 42, spaced apart from each other above and below. The upper underwater bearing 44 is attached inside the upper portion 42a, and the lower underwater bearing 44 is attached inside the lower portion 42b via a guide vane.

A disk-shaped support plate 45 larger than the underwater bearing 44 is disposed below the lower underwater bearing 44. The support plate 45 is positioned by a nut 46 screwed onto the bolt shaft portion 43a of the shaft portion 43. As a result, the entire rotating body 40 including the inner bellmouth 42 is placed on the support plate 45 and can rotate around the shaft portion 43.

The vanes 41 are arranged at equal intervals in the circumferential direction with respect to the inner bell mouth 42 and protrude radially outward from the inner bell mouth 42. In this embodiment, four vanes 41 are arranged at 90 degree intervals. However, it is sufficient that two or more vanes 41 are provided. Each vane 41 has a lower edge 41a, an outer edge 41b, a curved edge 41c, and an upper edge 41d.

The lower edge 41a is connected to the outer peripheral edge of the lower end of the inner bellmouth 42 and is inclined upward as it moves radially outward. The outer end of the lower edge 41a is located radially inward from the outer peripheral edge of the lower end of the bellmouth 24. The outer edge 41b is connected to the outer end of the lower edge 41a and is inclined radially outward as it moves upward so as to extend toward the outer peripheral portion of the lower end of the bellmouth 24 (suction port 24c). The curved edge 41c is connected to the upper end of the outer edge 41b and extends along the inner surface of the bellmouth 24. A uniform gap as small as possible is secured between the curved edge 41c and the inner surface of the bellmouth 24, within the range in which they do not interfere with each other due to the rotation of the rotor 43. The outer end of the upper edge 41d is connected to the upper end of the curved edge 41c, and the inner end of the upper edge 41d is connected to the upper part 42a of the inner bellmouth 42 within the bellmouth 24. In the slat 41 configured in this manner, the portion above the curved edge 41c protrudes into the bellmouth 24.

In the rotor 40 configured in this manner, the blade plate 41 has a portion that protrudes into the bell mouth 24, and this protruding portion receives the fluid force of the pre-swirling flow RF in the lift pipe 21, causing the blade plate 41 and the inner bell mouth 42 to rotate together. Here, in the suction tank 2 (outside the pump casing 20), a water flow occurs that depends on the shape of the suction tank 2 and the amount of suction from the suction port 24c, but the fluid force of this water flow is basically weaker than the fluid force of the pre-swirling flow RF in the lift pipe 21, so the rotor 40 rotates following the directions f1 and f2 of the pre-swirling flow RF. For example, the fluid force of the pre-swirling flow RF is a value equivalent to the fluid force acting on the fixed impeller shown in FIG. 5, and the fluid force of the water flow in the suction tank 2 is less than a value equivalent to the fluid force acting on the movable impeller shown in FIG. 5.

Specifically, in the excessive flow rate region shown in FIG. 6, the rotor 40 rotates in a direction f1 opposite to the direction R in which the impeller 33 rotates due to the pre-swirl flow RF. In the partial flow rate region shown in FIG. 6, the rotor 40 rotates in a direction f2, which is the same as the direction R in which the impeller 33 rotates due to the pre-swirl flow RF. In the rated operation region between the excessive flow rate region and the partial flow rate region shown in FIG. 6, the pre-swirl flow RF does not occur, so the rotor 40 does not rotate or rotates following the water flow in the suction tank 2.

The fluid force acting on the blade 41 due to the pre-swirl flow RF is shown in Figure 5. In Figure 5, the vertical axis is the fluid force F, and the horizontal axis is Δn, which is obtained by the following formula:

ｎ１：予旋回流の単位時間当たりの回転数
ｎ２：羽根板の単位時間当たりの回転数

n1: Number of revolutions per unit time of the pre-swirling flow n2: Number of revolutions per unit time of the blade

5, the fluid force F acting on the blade plate 41 increases as the difference Δn (rotational speed difference) between the circumferential rotation speed n1 of the pre-swirling flow RF and the circumferential rotation speed n2 of the blade plate 41 increases. When the blade plate is fixed, that is, when the blade plate is non-rotatable, the rotation speed n2 of the blade plate 41 is 0 (zero), so the fluid force F acting on the blade plate 41 is the highest. On the other hand, when the blade plate 41 is rotatable (movable) by the pre-swirling flow RF as in this embodiment, the fluid force F acting on the blade plate 41 can be released, so that the fluid force F acting on the blade plate 41 is significantly reduced compared to the fixed type. Therefore, the rigidity required for the movable blade plate 41 is lower than that required for the fixed blade plate. Therefore, since the rotor 40 including the blade plate 41 can be manufactured from industrial plastics, etc., the weight of the rotor 40 can be reduced, and as a result, the rotation speed n2 of the rotor 40 by the pre-swirling flow RF can also be increased. In addition, because the flow resistance of the pumped water caused by the rotor 40 can be reduced below the impeller 33 (the inlet side), the flow rate of the pre-swirling flow RF can be significantly faster than when a fixed blade plate is used.

On the other hand, the theoretical head Hth of the vertical pump 10 can be calculated using the following Euler formula:

ｇ：重力加速度
Ｕ_１：インペラ入口側の周速
Ｕ_２：インペラ出口側の周速
Ｃ_ｕ１：インペラ入口側の揚水の周方向の流速
Ｃ_ｕ２：インペラ出口側の揚水の周方向の流速

g: Gravitational acceleration _U1 : Peripheral speed at the impeller inlet side _U2 : Peripheral speed at the impeller outlet side _Cu1 : Peripheral flow velocity of the pumped water at the impeller inlet side _Cu2 : Peripheral flow velocity of the pumped water at the impeller outlet side

In the formula 2, the peripheral speed _U1 on the inlet side of the impeller 33 is the same as the peripheral speed _U2 on the outlet side. As is clear from the formula 2, the pump head Hth and the shaft power are suppressed lower as the flow velocity C _u1 of the pre-swirl flow RF in the same direction f2 as the direction R in which the impeller 33 rotates becomes faster. In the case of a fixed blade plate, the flow velocity C _u1 of the pre-swirl flow RF is reduced by flow resistance and approaches 0 (zero), so that the pump head Hth and the shaft power become high and the pump performance is reduced when the minimum flow is performed in the partial flow rate region shown in FIG. 6. On the other hand, in the case where the blade plate 41 can be rotated by the pre-swirl flow RF as in this embodiment, the reduction in the flow velocity C _u1 of the pre-swirl flow RF is suppressed by the following of the rotor 40, so that the pump head Hth and the shaft power become low and the pump performance is improved.

Fig. 6 is a graph showing changes in pump performance of the vertical pump 10. In Fig. 6, the vertical axis is the ratio H/Hopt of the head H to the optimum head Hopt, and the horizontal axis is the ratio Q/Qopt of the flow rate Q to the optimum flow rate Qopt. In Fig. 6, the thin line "C _u1 = 0" indicates the pump head H in the case of a fixed blade plate, and the thick line "+C _u1 " indicates the pump head H in the case of a movable blade plate 41.

In FIG. 6, although it depends on the specific speed, the region where the flow rate ratio Q/Qopt is less than about 70% is the partial flow rate region, the region where the flow rate ratio Q/Qopt is about 120% or more is the excessive flow rate region, and the range between these is the rated operation region. In normal operation, the motor 38 is controlled so that it is in the rated operation region or the excessive flow rate region, and in managed operation, the motor 38 is controlled so that it is in the partial flow rate region.

Referring to FIG. 6, in the case of the fixed blades shown by the thin lines, when operating in the partial flow range, as the flow rate ratio Q/Qopt decreases, the head ratio H/Hopt increases, so the pump head Hth and shaft power increase, and the pump performance decreases. In the case of the movable blades 41 shown by the thick lines, when operating in the partial flow range, as the flow rate ratio Q/Qopt decreases, the head ratio H/Hopt increases, but it is found to be significantly lower than in the case of the fixed blades. Therefore, when using a rotor 40 equipped with movable blades 41 as in this embodiment, the pump head Hth and shaft power can be lowered compared to when using fixed blades, and the pump performance can be improved.

The vertical pump 10 configured in this manner has the following features:

The vertical pump 10 is provided with a rotor 40 that has a plurality of vanes 41 whose upper ends protrude into the lift pipe 21 below (upstream) the impeller 33 and rotates following the pre-swirl flow RF caused by the rotation of the impeller 33. In other words, the rotor 40 rotates not by the water flow in the suction tank 2 but by the pre-swirl flow RF in the lift pipe 21. As a result, when the flow rate ratio Q/Qopt shown in FIG. 6 is higher than the maximum efficiency point, the rotor 40 rotates in the opposite direction f1 to the direction R in which the impeller 33 rotates due to the pre-swirl flow RF, and when the flow rate ratio Q/Qopt shown in FIG. 6 is lower than the maximum efficiency point, the rotor 40 rotates in the same direction f2 as the direction R in which the impeller 33 rotates due to the pre-swirl flow RF, and when the flow rate ratio Q/Qopt shown in FIG. 6 is near the maximum efficiency point, there is no rotation due to the pre-swirl flow RF.

As a result, when the minimum flow shown in FIG. 6 is executed, where the flow rate ratio Q/Qopt is lower than the maximum efficiency point, the speed decrease of the pre-swirling flow RF below the impeller 33 can be suppressed compared to the case where a non-rotatable vane is arranged. As a result, the speed difference between the pre-swirling flow RF and the swirling flow above (downstream) the impeller 33 can be reduced, so that the shaft power can be reduced when the minimum flow is executed, and the pump performance can be improved. In addition, the rotation of the multiple vanes 41 can destroy the air suction vortex SV in which air on the water surface is sucked into the water flow extending from the water surface to the suction port 24c shown in FIG. 2, and the underwater vortex UV in which gas (bubbles) due to cavitation are mixed into the water flow extending from the bottom 3 of the suction tank 2 to the suction port 24c, and the intrusion of gas into the lift pipe 21 can be suppressed.

The upper end of the blade plate 41 protrudes into the bell mouth 24 at the lower end of the lift pipe 21. This allows the rotor 40, which has multiple blade plates 41, to rotate reliably due to the pre-swirl flow RF below the impeller 33.

A shaft portion 43 protrudes from the impeller 33, the rotor 40 has an inner bell mouth 42 rotatably attached to the shaft portion 43, and the vane plates 41 protrude outward from the inner bell mouth 42. This allows the rotor 40, which has multiple vane plates 41, to rotate reliably by the pre-swirling flow RF below the impeller 33. In addition, because the conical cylindrical inner bell mouth 42 is arranged inside the conical cylindrical bell mouth 24, the water in the suction tank 2 can be smoothly sucked into the lift pipe 21.

Other embodiments and various modified examples of the present invention will be described below, but in these descriptions, points that are not specifically mentioned are the same as those in the first embodiment. In the drawings referred to below, elements that are the same as those in the first embodiment are given the same reference numerals.

Second Embodiment
7, the vertical pump 10 of the second embodiment differs from the vertical pump 10 of the first embodiment in that the rotor 40 is configured using a straight sleeve (inner cylindrical member) 50 instead of the inner bellmouth 42 shown in Fig. 2. In other words, the rotor 40 of the second embodiment is an example in which a plurality of vanes 41 are rotatably arranged on the lifting pipe 21.

Similar to the first embodiment shown in FIG. 2, the vanes 41 are provided at equal intervals in the circumferential direction with respect to the sleeve 50 and protrude radially outward from the sleeve 50. Each vane 41 has a lower edge 41a, an outer edge 41b, a curved edge 41c, and an upper edge 41d, and the portion above the curved edge 41c protrudes into the bellmouth 24.

In the rotor 40 of the second embodiment, as in the first embodiment shown in FIG. 2, the blade plate 41 has a portion that protrudes into the bell mouth 24. Therefore, the blade plate 41 and the sleeve 50 can rotate together due to the pre-swirl flow RF generated in the lift pipe 21. Therefore, the same action and effect as in the first embodiment can be obtained.

Third Embodiment
8 and 9, the vertical pump 10 of the third embodiment differs from the vertical pump 10 of the first embodiment in that a shaft portion 43 is provided on a retaining member 55 joined to the lower end of the bell mouth 24, and a rotor 40 is rotatably disposed on this shaft portion 43.

The holding member 55 is provided to rotatably position the rotating body 40. The holding member 55 is frame-shaped and includes a base 55a, multiple frame members 55c, and a joint frame 55g.

The base 55a is disk-shaped and is disposed on the axis A of the water lift pipe 21. The base 55a is provided with a mounting hole 55b that penetrates in the vertical direction in order to attach the shaft 43. For example, the shaft 43 can be positioned on the base 55a so that it cannot rotate by passing the lower end of the shaft 43 through the mounting hole 55b and inserting a key that has penetrated the base 55a into the shaft 43.

The multiple frame members 55c are provided at equal intervals in the circumferential direction with respect to the base 55a and protrude radially outward from the base 55a. A sufficient space is provided between adjacent frame members 55c in the circumferential direction so as not to impede the flow of water in the water intake tank 2. In this embodiment, four frame members 55c are provided at 90 degree intervals. However, the number of frame members 55c may be three or five or more.

Each frame member 55c has a lower portion 55d and a side portion 55e. The lower portion 55d extends along the lower edge 41a of the rotor 40 in a direction perpendicular to the axis A of the lift pipe 21. The side portion 55e is connected to the outer end of the lower portion 55d and extends along the outer edge 41b of the rotor 40 toward the outer periphery of the lower end of the bellmouth 24. Adjacent frame members 55c in the circumferential direction are connected via an annular continuous portion 55f.

The joining frame 55g is provided to join the retaining member 55 to the lower end of the bell mouth 24. The joining frame 55g is made of an annular plate with a diameter corresponding to the outer periphery of the lower end of the bell mouth 24, and is joined to the upper end of each of the multiple frame members 55c. This joining frame 55g has multiple bolt holes 55h for joining to the bell mouth 24, spaced at equal intervals in the circumferential direction.

The shaft portion 43 is separate from the rotating shaft 30, and is inserted into the mounting hole 55b of the holding member 55 so as to extend upward along the axis A of the water lift pipe 21, and is attached to the base portion 55a so as not to rotate. The lower and upper ends of the shaft portion 43 are each provided with a bolt shaft portion 43a for rotatably supporting the rotating body 40.

The rotor 40 has a configuration in which multiple vane plates 41 are provided on the outer periphery of the inner bell mouth 42, similar to the first embodiment shown in FIG. 2. In other words, the rotor 40 of the third embodiment is an example in which multiple vane plates 41 and the inner bell mouth 42 are rotatably arranged on the lift pipe 21. However, the rotor 40 of the third embodiment may have multiple vane plates 41 provided on the outer periphery of the sleeve 50, similar to the second embodiment shown in FIG. 7, and the multiple vane plates 41 may be rotatably arranged on the lift pipe 21.

The inner bellmouth 42 is rotatably attached to the shaft 43 via an underwater bearing 44. Support plates 45 are arranged at the lower and upper ends of the inner bellmouth 42, and these support plates 45 are positioned by nuts 46 screwed onto the bolt shaft 43a of the shaft 43. The blade 41 has a lower edge 41a, an outer edge 41b, a curved edge 41c, and an upper edge 41d, and the part above the curved edge 41c protrudes into the bellmouth 24.

The rotor 40 of the third embodiment is attached to a fixed shaft portion 43 provided on a retaining member 55, unlike the rotor 40 of the first embodiment. On the other hand, in this rotor 40, like the rotor 40 of the first embodiment, the blade plate 41 has a portion that protrudes into the bellmouth 24. Therefore, the blade plate 41 and the inner bellmouth 42 can rotate together due to the pre-swirl flow RF generated in the lift pipe 21. Therefore, the same action and effect as the first embodiment can be obtained.

Fourth Embodiment
Referring to Figure 10, the vertical pump 10 of the fourth embodiment differs from the third embodiment in that the shaft portion 43 is rotatably disposed on the base 55a of the retaining member 55, and the rotor 40 rotates integrally with the shaft portion 43.

The underwater bearing 44 is attached to the mounting hole 55b provided in the base 55a of the retaining member 55. As in the first embodiment shown in FIG. 2, a holder 48 is provided in the bellmouth 24 via a guide vane 48a, and the underwater bearing 47 is attached in this holder 48.

The rotor 40 has a configuration in which multiple vanes 41 are provided on the outer periphery of the inner bell mouth 42, similar to the first embodiment shown in FIG. 2. In other words, the rotor 40 of the fourth embodiment is an example in which multiple vanes 41, the inner bell mouth 42, and the shaft 43 are rotatably arranged on the lift pipe 21. However, the rotor 40 of the fourth embodiment may have multiple vanes 41 provided on the outer periphery of the sleeve 50, similar to the second embodiment shown in FIG. 7, and may be configured so that the multiple vanes 41 can rotate together with the shaft 43 on the lift pipe 21, or the multiple vanes 41 may be directly protruded from the shaft 43.

The upper part 42a of the inner bell mouth 42 and the shaft part 43 each have a through hole that penetrates in the radial direction, and a key 60 is inserted into these through holes. By attaching this key 60, the rotor 40 and the shaft part 43 can rotate together.

A circular support part 61 is provided integrally within the inner bell mouth 42 via a number of ribs 62. The rotating body 40 is disposed within the retaining member 55 by placing this support part 61 on the base part 55a. The support part 61 is preferably formed of a metal plate. When the rotating body 40 is molded from industrial plastic as in this embodiment, the metal support part 61 is provided integrally by insert molding. When the rotating body 40 is formed from metal, the support part 61 is provided integrally by joining.

The lower end of the shaft 43 is rotatably supported by an underwater bearing 44 arranged in the holding member 55, and the upper end of the shaft 43 is rotatably supported by an underwater bearing 47 arranged in the holder 48. The lower end of the shaft 43 penetrates the support portion 61 and the base 55a of the holding member 55, protruding downward. A support plate 45 is arranged on the lower end side of the shaft 43, and a nut 46 is screwed onto the bolt shaft 43a.

In the rotor 40 of the fourth embodiment, as in the first embodiment shown in FIG. 2, the blade plate 41 has a portion that protrudes into the bell mouth 24. Therefore, the blade plate 41 and the inner bell mouth 42 can rotate together due to the pre-swirl flow RF generated in the lift pipe 21. Therefore, the same action and effect as in the first embodiment can be obtained.

Fifth Embodiment
11 and 12 , the vertical pump 10 of the fifth embodiment differs from the first embodiment in that the rotor 40 is rotatably disposed on the lift pipe 21 by a support member 65 provided on the bellmouth 24 and a support portion 66 provided on the rotor 40, without employing a shaft portion 43. However, the support member 65 may be provided on the rotor 40, and the support portion 66 may be provided on the bellmouth 24.

The support member 65 is a ring made of metal or ceramics, and is attached to the outer periphery of the lower end of the bellmouth 24. The support member 65 is preferably composed of a number of divided bodies obtained by dividing the ring in the circumferential direction. The support member 65 is provided with an attachment groove 65a for attachment to the bellmouth 24. The support member 65 is also provided with a rail portion 65b that protrudes downward and has an L-shaped cross section.

The support portion 66 is an annular plate provided at the upper end of the outer edge 41b of each of the plurality of blades 41, and is rotatably supported by the support member 65. The outer periphery of the support portion 66 protrudes radially outward from the blade 41 and is fitted into the rail portion 65b of the support member 65. However, the support portion 66 is not limited to an annular plate, and may be a fan-shaped plate provided for each blade 41. The support portion 66 is preferably formed of a metal or ceramic plate. When the rotor 40 is molded from industrial plastic as in this embodiment, the metal or ceramic support portion 66 is integrally provided by insert molding. When the rotor 40 is formed from metal, the metal support portion 66 is integrally provided by joining.

The rotor 40 has a configuration in which multiple vane plates 41 are provided on the outer periphery of the inner bell mouth 42, similar to the first embodiment shown in FIG. 2. In other words, the rotor 40 of the fourth embodiment is an example in which multiple vane plates 41 and the inner bell mouth 42 are rotatably arranged on the lift pipe 21. The rotor 40 is rotatably attached to the lift pipe 21 by arranging the support portion 66 on the rail portion 65b.

In the rotor 40 of the fifth embodiment, as in the first embodiment shown in FIG. 2, the blade plate 41 has a portion that protrudes into the bellmouth 24. Therefore, the blade plate 41 and the inner bellmouth 42 can rotate together due to the pre-swirl flow RF generated in the lift pipe 21. Therefore, the same action and effect as in the first embodiment can be obtained.

Sixth Embodiment
13, the vertical pump 10 of the sixth embodiment differs from the fifth embodiment in that the inner bellmouth 42 shown in Fig. 12 is not provided on the rotor 40. The rotor 40 of the sixth embodiment is also not provided with the sleeve 50 shown in Fig. 7. In other words, the rotor 40 of the sixth embodiment is an example in which only the plurality of vane plates 41 are rotatably disposed on the rise pipe 21. The plurality of vane plates 41 are connected to each other on the axis A of the rise pipe 21.

In the sixth embodiment of the rotor 40, as in the first embodiment shown in FIG. 2, the blade plate 41 has a portion that protrudes into the bellmouth 24. Therefore, the blade plate 41 can be rotated by the pre-swirl flow RF generated in the lift pipe 21. Therefore, the same action and effect as in the first embodiment can be obtained.

Seventh Embodiment
With reference to FIG. 14 , the vertical pump 10 of the seventh embodiment differs from the first embodiment in that the joint portion 24 a and the bellmouth body 24 b of the bellmouth 24 are configured as separate bodies, and the bellmouth body 24 b is made rotatable integrally with the rotating body 40.

The bellmouth body 24b gradually widens from top to bottom, is joined to the blade plate 41, and is located below the joint 24a. A uniform gap as small as possible is maintained between the bellmouth body 24b and the joint 24a, within the range where they do not interfere with each other due to the rotation of the rotor 43.

The rotor 40 is an integral structure of the vane plate 41, the inner bellmouth 42, and the bellmouth body 24b, and is rotatably attached to a shaft 43 that protrudes downward from the impeller 33. The upper part of the inner bellmouth 42 protrudes into the bellmouth body 24b (the lift pipe 21) and is surrounded by the bellmouth body 24b.

The vanes 41 are arranged at equal intervals in the circumferential direction and extend in the radial direction, and are integrally attached to the inner bellmouth 42 and the bellmouth body 24b by joining. The vanes 41 have a lower edge 41a, an outer edge 41b, a curved edge 41c, and an upper edge 41d. Of these, the bellmouth body 24b is joined to the curved edge 41c. The upper edge 41d is located within the bellmouth body 24b.

In the seventh embodiment configured in this manner, as in the first embodiment shown in FIG. 2, the rotation of the impeller 33 causes water in the suction tank 2 to be sucked into the pump casing 20 through the suction port 24c of the bellmouth body 24b. Then, below (upstream of) the impeller 33, a pre-swirling flow RF is generated with directions f1 and f2 according to the rotation speed of the impeller 33 by the motor 38. This pre-swirling flow RF is generated not only within the joint 24a but also within the bellmouth body 24b.

In the seventh embodiment of the rotor 40, the vane plate 41 has a portion that protrudes into the bellmouth body 24b. Therefore, the vane plate 41, the inner bellmouth 42, and the bellmouth body 24b can rotate together due to the pre-swirling flow RF generated in the lift pipe 21. Therefore, the same action and effect as in the first embodiment can be obtained. Moreover, in the seventh embodiment, since the bellmouth body 24b can also rotate together with the vane plate 41, the air suction vortex SV generated in the suction tank 2 can be eliminated by the turbulence T that can occur in the outer part of the bellmouth body 24b.

Eighth embodiment
15, the vertical pump 10 of the eighth embodiment differs from the vertical pump 10 of the seventh embodiment in that the rotor 40 is configured using a straight tube-shaped sleeve 50 instead of the inner bellmouth 42 shown in Fig. 14. In other words, the rotor 40 of the eighth embodiment is an example in which a plurality of vanes 41 and a bellmouth body 24b are rotatably arranged on the rise pipe 21.

The vanes 41 are arranged at equal intervals in the circumferential direction and are integrally provided between the sleeve 50 and the bellmouth body 24b by joining. Each vane 41 has a lower edge 41a, an outer edge 41b, a curved edge 41c, and an upper edge 41d, and the bellmouth body 24b is joined to the curved edge 41c. The upper edge 41d is located within the bellmouth body 24b.

In the rotor 40 of the eighth embodiment, as in the seventh embodiment, the blade plate 41 has a portion that protrudes into the bellmouth body 24b. Therefore, the blade plate 41 and the sleeve 50 can rotate together due to the pre-swirl flow RF generated in the lift pipe 21. Therefore, the same action and effect as in the seventh embodiment can be obtained.

The present invention is not limited to the configuration of the above embodiment, and various modifications are possible.

For example, in the first embodiment shown in FIG. 2 to the eighth embodiment shown in FIG. 15, the upper end of only one of the vane plates 41 may protrude into the bellmouth body 24b.

In the seventh embodiment shown in FIG. 14, as in the fifth embodiment shown in FIG. 11, a support member 65 may be provided at the lower end of the joint 24a, and a support part 66 may be provided at the upper end of the bellmouth body 24b (bellmouth 24), so that the vane plates 41, the inner bellmouth 42, and the bellmouth body 24b can rotate together. In this case, as in the sixth embodiment shown in FIG. 13, the vane plates 41 and the bellmouth 24 can rotate together without providing either the inner bellmouth 42 or the sleeve 50.

The pump may be a submersible motor pump with a motor disposed inside the lift pipe, and may have a configuration in which an impeller is rotatably disposed at the bottom of the lift pipe.

1 Installation floor 2 Suction tank 3 Bottom 5 Discharge pipe 6 Gate valve 10 Vertical pump (pump)
20 Pump casing 21 Lifting pipe 22 Lifting pipe body 23 Vane case 24 Bell mouth 24a Joint 24b Bell mouth body (bell mouth)
24c Suction port 25 Guide vane 26 Bearing casing 27 Discharge elbow 28 Base plate 30 Rotating shaft 33 Impeller 34 Hub 35 Blade 38 Motor 40 Rotating body 41 Blade plate 41a Lower edge 41b Outer edge 41c Curved edge 41d Upper edge 42 Inner bell mouth (inner cylinder member)
42a Upper portion 42b Lower portion 43 Shaft portion 43a Bolt shaft portion 44 Underwater bearing 45 Support plate 46 Nut 47 Underwater bearing 48 Holder 48a Guide vane 50 Sleeve (inner cylinder member)
55 Holding member 55a Base 55b Mounting hole 55c Frame material 55d Lower portion 55e Side portion 55f Continuous portion 55g Joint frame 55h Bolt hole 60 Key 61 Support portion 62 Rib 65 Support member 65a Mounting groove 65b Rail portion 66 Support portion RF Pre-swirl flow SV Air suction vortex UV Underwater vortex T Turbulence A Axis of lift pipe

Claims (9)

A cylindrical lift pipe extending vertically;
an impeller disposed in a lower portion of the water lift pipe and rotatable around an axis of the water lift pipe;
a rotor having a plurality of radially protruding blades, disposed below the impeller of the water lifting pipe, and rotatable about the axis;
The rotating body has an upper end of at least one of the plurality of blades protruding into the lifting pipe, and rotates in response to a pre-swirl flow of the pumped water below the impeller caused by the rotation of the impeller. The lift pipe has a conical bell mouth joined to a lower end thereof,
The pump according to claim 1 , wherein an upper end of at least one of the plurality of vanes protrudes into the bellmouth. A shaft portion protruding downward from the impeller,
The rotating body has a cylindrical inner cylinder member rotatably attached to the shaft portion,
The plurality of blades protrude outward from the inner tube member.
3. The pump of claim 2. a frame-shaped retaining member having a plurality of frame members extending in a radial direction of the bell mouth and joined to a lower end of the bell mouth;
a shaft portion provided on the holding member so as to extend upward along the axis,
The rotating body has a cylindrical inner cylinder member rotatably attached to the shaft portion,
The plurality of blades protrude outward from the inner tube member.
3. The pump of claim 2. A support member provided on one of the bell mouth and the rotor;
The pump according to claim 2 , further comprising: a support portion provided on the other of the bell mouth and the rotor, the support portion being rotatably supported by the support member. The rotor has a conical cylindrical inner bell mouth extending along the axis,
The plurality of slats protrude outwardly from the inner bell mouth.
6. The pump of claim 5. A shaft portion protruding downward from the impeller,
The lift pipe has a conical bell mouth disposed at a lower end thereof,
the rotor has a cylindrical inner cylinder member rotatably attached to the shaft portion such that at least an upper portion of the inner cylinder member is located within the bell mouth,
The plurality of vanes are provided between the inner cylinder member and the bell mouth such that upper ends of the vanes protrude into the bell mouth,
The rotating body is rotatable integrally with the bell mouth.
2. The pump of claim 1. The pump according to any one of claims 3, 4, and 7, wherein the inner cylinder member is a conical inner bell mouth. The pump according to any one of claims 3, 4, and 7, wherein the inner cylinder member is a straight sleeve.

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