pump

Abstract

To provide a pump using a valve which does not require a drive source, for enabling automatic opening / closing of the valve depending on an operating condition.SOLUTION: A pump 10 includes a pump casing 12, an impeller 16, and a bypass pipe 20 for allowing part of pumped water discharged through the pump casing 12 to flow out to the outside of the pump casing 12. In the bypass pipe 20, there are provided a flap valve 35 to be turnable from a closed state to an opened state when a pressure in the pump casing 12 is higher than a pressure in the bypass pipe 20, and an adjustment mechanism 50 for adjusting force to keep the flap valve 35 in the closed state.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a pump. [Background technology]

[0002] Patent Document 1 discloses a pump in which a bypass pipe is connected to the pump casing and an on-off valve is placed in the bypass pipe, and the on-off valve is opened during maintenance operation that is not intended for drainage, allowing a portion of the pumped water to be returned to the suction tank through the bypass pipe. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5063744 Summary of the Invention [Problem to be solved by the invention]

[0004] The pump of Patent Document 1 uses an electric butterfly valve as an on-off valve, which does not require a drive source, and does not take into consideration automatic opening and closing of the valve depending on the operating state.

[0005] An object of the present invention is to provide a pump that uses a valve that does not require a drive source and that can automatically open and close the valve depending on the operating state. [Means for solving the problem]

[0006] The present invention provides a pump pumping system comprising: a cylindrical pump casing partially disposed within a suction tank; an impeller rotatably disposed within the pump casing for discharging water from the suction tank; a bypass pipe disposed outside the pump casing, branching off from the pump casing downstream of the impeller, and for allowing a portion of the pumped water discharged through the pump casing to flow out of the pump casing; a flap valve having a rotating shaft rotatably supported on the bypass pipe, which is rotatable in a direction away from the pump casing from a closed state that blocks the outflow of the pumped water to an open state that allows the outflow of the pumped water when the pressure within the pump casing becomes higher than the pressure within the bypass pipe; and an adjustment mechanism attached to the rotating shaft for adjusting a force that maintains the flap valve in the closed state. At least one end of the rotary shaft penetrates the bypass pipe and protrudes to the outside, and an arm is provided at the one end of the rotary shaft, and the adjustment mechanism includes a biasing member that is connected to the arm and is constituted by a constant-load spiral spring that biases the flap valve to a closed position via the arm and the rotary shaft. Provide a pump.

[0007] A flap valve is attached to the bypass pipe, which can rotate from a closed state to an open state when the pressure inside the pump casing becomes higher than the pressure inside the bypass pipe. The pressure inside the bypass pipe is higher than the pressure inside the pump casing during normal operation for drainage purposes, and lower than the pressure inside the pump casing during maintenance operation for non-drainage purposes. Therefore, the flap valve is closed during normal operation and open during maintenance operation. The flap valve does not require a drive source to switch between the open and closed states, reducing the running costs of the pump equipment. Furthermore, the rotating shaft of the flap valve is equipped with an adjustment mechanism to adjust the force that keeps the flap valve closed, allowing the pressure difference (timing) at which the flap valve opens and closes to be adjusted. This allows the flap valve to automatically open and close reliably according to the operating conditions, switching to the closed state during normal operation and the open state during maintenance operation. [Effects of the Invention]

[0008] The pump of the present invention uses a valve that does not require a drive source, and can automatically open and close the valve depending on the operating state. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a pump according to an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged cross-sectional view of part II in FIG. [Figure 3] FIG. 3 is an enlarged cross-sectional view of part III in FIG. 2 . [Figure 4] FIG. 4 is an enlarged cross-sectional view of part IV in FIG. 2 . [Figure 5] Right side view of Figure 4. [Figure 6] Partial cross-sectional view of Figure 5. [Figure 7] FIG. 4 is a diagram showing the relationship between an arm, a weight, and a spiral spring. [Figure 8] FIG. 10 is a diagram showing the spring material in a non-connected state. [Figure 9] Graph showing the relationship between load and deflection of spring material. [Figure 10] FIG. [Figure 11] Graph showing changes in pump performance. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] Referring to FIG. 1, a vertical shaft pump (pump) 10 according to an embodiment of the present invention is fixed to an installation floor 1 of a drainage pumping station, and discharges rainwater and the like that has flowed into a suction tank 2 located below the installation floor 1 downstream.

[0012] The vertical pump 10 comprises a pump casing 12, a rotating shaft 15, an impeller 16, a motor 17, and a control unit 18, and is capable of performing normal operation for the purpose of draining water and maintenance operation for the purpose of not draining water using the control unit 18. Maintenance operation is performed for the purpose of maintaining the performance of the vertical pump 10 when normal operation has not been performed for a long period of time, and the motor 17 (impeller 16) is rotated at a slower speed (lower rotational frequency) than during normal operation to minimize the discharge volume. This maintenance operation includes mini-flow operation, which is performed with the gate valve 6 open, and shut-off operation, which is performed with the gate valve 6 closed.

[0013] In the vertical pump 10 of this embodiment, a bypass pipe 20 is branched off and connected to the pump casing 12, allowing a portion of the pumped water to flow out of the pump casing 12. A flap valve 35, which does not require a driving source, is attached to the bypass pipe 20, allowing a portion of the pumped water to flow out only during maintenance operation. An adjustment mechanism 50 is provided in the bypass pipe 20 to adjust the timing at which the flap valve 35 switches between open and closed states.

[0014] The configuration of the vertical pump 10 of this embodiment will be specifically described below.

[0015] Referring to Fig. 1, pump casing 12 is inserted into a through-hole formed in installation floor 1 and fixed to installation floor 1. Pump casing 12 includes a lifting pipe 13 arranged in suction tank 2 and a discharge elbow 14 arranged on installation floor 1. Lifting pipe 13 extends in the vertical direction and includes suction ports 13a arranged at intervals on the bottom 3 of suction tank 2. Discharge elbow 14 is a bent pipe whose axis is bent 90 degrees, and is connected to discharge pipe 5 equipped with gate valve 6 (which is normally closed in this embodiment and can be opened and closed manually).

[0016] The rotating shaft 15 passes through the discharge elbow 14 and is disposed along the axis A of the riser pipe 13. The rotating shaft 15 is rotatably supported by a bearing disposed inside the riser pipe 13.

[0017] The impeller 16 is attached to the lower end of the rotating shaft 15 so as to be located at the bottom inside the lifting pipe 13. The impeller 16 rotates integrally with the rotating shaft 15 and discharges water from the suction tank 2 through the inside of the pump casing 12.

[0018] The motor 17 is a drive source mechanically connected to the upper end of the rotary shaft 15 located outside the pump casing 12. The motor 17 is electrically connected to the control unit 18 via a drive circuit, and the control unit 18 controls the motor 17 to rotate the impeller 16 via the rotary shaft 15 at a predetermined rotation speed.

[0019] Control unit 18 is configured by a personal computer. However, control unit 18 may also be configured by a single or multiple microcomputers and other electronic devices. Control unit 18 determines whether to perform normal operation, maintenance operation, or operation shutdown based on the water level detection result, for example, from a water level sensor disposed in suction tank 2, and controls motor 17 so that rotating shaft 15 rotates at a rotation speed determined according to the operation to be performed. Control unit 18 stops rotation of motor 17 when operation is shutdown, rotates motor 17 at a constant speed to minimize discharge volume when performing maintenance operation, and rotates motor 17 at a constant speed higher than that when performing normal operation.

[0020] Continuing to refer to Figure 1, two bypass pipes 20 are provided at opposing positions outside the rise pipe 13. However, the number of bypass pipes 20 may be one, or three or more. Each bypass pipe 20 includes a horizontal pipe (first pipe) 21 branching off from the discharge elbow 14 downstream (above) of the impeller 16, and a vertical pipe (second pipe) 22 branching off from the horizontal pipe 21.

[0021] Referring to FIG. 2, the horizontal pipe 21 has an inner end 21a connected to the discharge elbow 14 and an outer end (end) 21b remote from the discharge elbow 14. The horizontal pipe 21 is a straight pipe extending in a direction perpendicular to the axis A of the pumping pipe 13 (see FIG. 1). The interior of the horizontal pipe 21 and the interior of the pump casing 12 are spatially connected, allowing a portion of the pumped water in the pump casing 12 to flow into the horizontal pipe 21. The inner diameter of the horizontal pipe 21 is smaller than the inner diameter of the pump casing 12 (e.g., by 30 to 40%). However, the extension direction of the horizontal pipe 21 does not have to be a perpendicular direction in the strict geometric sense, as long as the interior of the pump casing 12 can be seen through the opening of the inner end 21a when viewed from the opening of the outer end 21b. The horizontal pipe 21 may also be a curved pipe.

[0022] 3, horizontal pipe 21 has a cylindrical connection portion 21c that protrudes downward and connects to vertical pipe 22. Horizontal pipe 21 has a cylindrical portion 21d that protrudes upward at a position opposite connection portion 21c. Cylindrical portion 21d is covered with a transparent lid 24. This allows the interior of vertical pipe 22 to be seen through lid 24.

[0023] 3 and 6, the horizontal pipe 21 is provided with a bearing portion 21e, an insertion portion 21f, and a fixed valve seat 39 for mounting the flap valve 35. The specific configurations of these will be described in detail later.

[0024] Referring to FIG. 1 , the vertical pipe 22 is a straight pipe and extends along the lifting pipe 13. The vertical pipe 22 has an upper end (first end) 22a connected to the connecting portion 21c of the horizontal pipe 21, and a lower end (second end) 22b disposed in the suction tank 2. The interior of the vertical pipe 22 is spatially connected to the interior of the horizontal pipe 21, and has a total length that allows water that has flowed into the horizontal pipe 21 to flow out from the lower end 22b to the bottom 3 of the suction tank 2. However, the vertical pipe 22 may have any length as long as it is able to allow water to flow out into the suction tank 2, or it may be a curved pipe. The diameter of the vertical pipe 22 may be different from the diameter of the horizontal pipe 21 as long as it allows water to flow out into the suction tank 2.

[0025] An endless ring-shaped pipe 23 surrounding the rise pipe 13 is connected to the lower ends 22b of the two vertical pipes 22. The ring-shaped pipe 23 is annular about the axis A of the rise pipe 13, and is disposed between the suction port 13a and the impeller 16. A plurality of nozzles 23a that discharge water toward the bottom 3 of the suction tank 2 are provided at intervals in the circumferential direction on the ring-shaped pipe 23. This allows the water discharged from the nozzles 23a to scrape up sludge on the bottom 3 of the suction tank 2 and to be discharged together with the water in the suction tank 2. Note that the vertical pipes 22 may not be provided with ring-shaped pipes 23, and the nozzles 23a may be provided at the lower ends 22b of the vertical pipes 22, or the lower ends 22b of the vertical pipes 22 may be open inside the suction tank 2.

[0026] 3 and 5, the outer end 21b of the horizontal pipe 21 is closed by an end plate 25 to which an openable and closable door 26 is attached.

[0027] End plate 25 is a metal ring having an opening 25a. End plate 25 is attached liquid-tight to outer end 21b of horizontal pipe 21, and opening 25a is formed so that its center coincides with the axis of horizontal pipe 21. End plate 25 is provided with bolt holes (not shown) for fastening door 26 in a closed state, and a retaining portion 28 for holding door 26 in an open state. Retaining portion 28 is made of a plate attached below opening 25a and extends along installation floor 1 (see Figure 1).

[0028] Door 26 is a disk-shaped member with a diameter larger than the diameter of opening 25a, and when closed, the gap between door 26 and end plate 25 is sealed by a sealing member (not shown). Door 26 is made of a transparent plate with translucency, and the inside of horizontal piping 21 can be seen from the outside through opening 25a. Therefore, the open / closed state of flap valve 35 can be easily confirmed through door 26 during both normal operation and maintenance operation. Furthermore, during maintenance operation, the return state of a portion of the pumped water can be easily confirmed through door 26. However, as long as only the portion of door 26 corresponding to opening 25a is translucent, the other portions may be opaque and not translucent.

[0029] A hinge 27 is attached to the lower end of the door 26, and a pair of eyebolts (fastening members) 29 are attached circumferentially spaced apart on the upper side opposite the hinge 27. As shown most clearly in FIG. 3, the hinge 27 is attached to a holder 28. When the hinge 27 abuts against the holder 28, the door 26 is held in an open position (open position) so that it extends along the axis of the horizontal pipe 21. This allows the door 26 to be used as a support for inserting a measuring instrument such as an endoscope during inspection inside the pump casing 12. The eyebolt 29 is attached to the door 26 via a bracket 30. The door 26 is maintained in the closed state by rotating the door 26 from the open position to the closed position and tightening the eyebolt 29 into the bolt hole.

[0030] 1, the flap valve 35 opens and closes based on the difference between the pressure P in the discharge elbow 14, the pressure Pd outside the flap valve 35 in the bypass pipe 20 outside the discharge elbow 14 (hereinafter referred to as the "pressure in the horizontal pipe 21"), and the pressure Ps in the suction tank 2. Referring to FIGS. 3 and 6, the flap valve 35 includes a valve element 36 having a rotating shaft 37, and a fixed valve seat 39 provided in the horizontal pipe 21.

[0031] The valve element 36 can rotate integrally with a horizontally extending rotary shaft 37 via an arm. The rotary shaft 37 is inserted into an insertion portion 21f formed in the horizontal pipe 21 and supported by a bearing portion 21e. The bearing portion 21e and the insertion portion 21f are provided at an upper portion of the horizontal pipe 21, closer to the inner end 21a than the connection portion 21c. The bearing portion 21e is a recess recessed radially outward from the internal space of the horizontal pipe 21. The insertion portion 21f is provided on the opposite side of the axis of the horizontal pipe 21 from the bearing portion 21e and is a hole penetrating from the internal space of the horizontal pipe 21 to the outside. A seal member 40 is attached to the insertion portion 21f to seal the rotary shaft 37. The portion of the rotary shaft 37 protruding from the insertion portion 21f is supported by a bearing member 42 equipped with a ball bearing 41.

[0032] 3, the surface of the valve element 36 that faces the discharge elbow 14 in the closed state is provided with an annular movable valve seat 38. In the horizontal pipe 21, below the bearing portion 21e and the insertion portion 21f and on the discharge elbow 14 side of the valve element 36 in the closed state, an annular fixed valve seat 39 is provided. When the valve element 36 rotates away from the discharge elbow 14 (valve opening), the movable valve seat 38 moves away from the fixed valve seat 39, and when the valve element 36 rotates toward the discharge elbow 14 (valve closing), the movable valve seat 38 is pressed against the fixed valve seat 39.

[0033] During normal operation, the pressure P in the discharge elbow 14 is lower than the pressure Pd in the horizontal pipe 21 and the pressure Ps in the water suction tank 2 (P < Pd ≦ Ps). As a result, the flap valve 35 rotates to the closed position shown by the solid line in Fig. 3, and the movable valve seat 38 is pressed against the fixed valve seat 39 to block the pumping water from flowing from the discharge elbow 14 into the horizontal pipe 21 (closed state). During the control operation, especially during the cut-off operation and the mini-flow operation, the pressure P in the discharge elbow 14 is higher than the pressure Pd in the horizontal pipe 21 and the pressure Ps in the water suction tank 2 (P > Pd ≧ Ps). As a result, the flap valve 35 rotates to the open position side shown by the dashed line in Fig. 3 so that the movable valve seat 38 separates from the fixed valve seat 39, allowing a part of the pumped water in the discharge elbow 14 to flow in (open state). The open state means not only the state of rotating to the open position shown by the dashed line in Fig. 3, but also the state where the movable valve seat 38 of the flap valve 35 is separated from the fixed valve seat 39 and the pumped water in the discharge elbow 14 can flow in. The opening angle of the flap valve 35, which is the valve opening degree, varies depending on the difference between the pressure P in the discharge elbow 14 and the pressure Pd in the horizontal pipe 21.

[0034] Referring to Figs. 4 and 6, the adjustment mechanism 50 is provided to adjust the force for maintaining the flap valve 35 in the closed state, and is attached to the portion of the rotary shaft 37 that protrudes externally from the horizontal pipe 21 through the insertion portion 21f. The adjustment mechanism 50 includes an arm 51 attached to the rotary shaft 37, a spring 52 and a weight 56 attached to the arm 51. Further, a damper 57 is attached to the arm 51.

[0035] The arm 51 is attached to the outer end of the rotary shaft 37 and is a rod body extending away from the rotary shaft 37. The arm 51 has a first portion 51a protruding to the right from the rotary shaft 37 in FIG. 4 and a second portion 51b protruding to the left from the rotary shaft 37 in FIG. 4. The arm 51 extends horizontally when the flap valve 35 is in the closed position, and can rotate the flap valve 35 to the open position by manually operating the arm 51 counterclockwise in FIG. 4. When the flap valve 35 is in the closed position, the flap valve 35 abuts against the fixed valve seat 39, and therefore the arm 51 cannot be operated clockwise in FIG. 4. When the arm 51 is opened and released, the weight of the flap valve 35, the weight of the arm 51, the biasing force of the spiral spring 52, and the weight of the weight 56 ​​cause the flap valve 35 to rotate to the closed position.

[0036] 4 and 7, the power spring 52 is connected to the first portion 51a of the arm 51 via the weight 56, and is a biasing member that biases the flap valve 35 to the closed position via the arm 51 and the rotary shaft 37. The power spring 52 is of a constant load type, and includes a strip-shaped spring material 53 mechanically connected to the weight 56, and a winding member 54 that winds up the spring material 53 so that it can be unwound.

[0037] 8, spring material 53 has tip portion 53a on the tip side and linear portion 53b on the base end side connected to tip portion 53a. Tip portion 53a of spring material 53 has connection hole 53c for connection to weight 56. Referring to FIG. 9, at tip portion 53a, the relationship between the load (returning force) and the unwound length is nonlinear (initial deflection e). Therefore, when the unwound length from winding member 54 falls within the range of tip portion 53a, the load increases as unwinding from winding member 54 progresses. At linear portion 53b, the relationship between the load and the unwound length is linear (constant). Therefore, once the unwound length from winding member 54 reaches linear portion 53b, the load remains constant even if unwinding from winding member 54 progresses further. If the diameter of winding portion 54a, which will be described later, increases, the length of tip portion 53a (the portion where initial deflection e occurs) also increases. For example, if the diameter of the winding portion 54a is 100 mm, the length of the tip portion 53a is approximately 30 mm to 330 mm. However, the length of the tip portion 53a (the portion where the initial deflection e occurs) can vary depending on the shape and material of the spring material 53.

[0038] 7 and 8, the winding member 54 is a bobbin capable of spirally winding the spring material 53, and includes a mounting flange 54b at one end of a cylindrical winding portion 54a for mounting to the horizontal pipe 21. The center C1 of the winding portion 54a and the center C2 of the mounting flange 54b are eccentric to each other. The mounting flange 54b has a plurality of (four in this embodiment) mounting holes 54c formed at intervals (equally spaced 90 degrees apart in this embodiment) around the center C2.

[0039] 7 and 10, the mounting portion 55 is provided to protrude from the outer surface of the horizontal pipe 21. However, the mounting portion 55 may be provided on the pump casing 12 or the installation floor 1, as long as it is a fixed, rigid body. The mounting portion 55 has a plurality of bolt holes 55a corresponding to the mounting holes 54c, spaced apart around the center C3. Because the center C1 of the winding portion 54a and the center C2 of the mounting flange 54b are eccentric, changing the attitude (position) of the winding portion 54a relative to the mounting portion 55 changes the position of the center C1 of the winding portion 54a relative to the mounting portion 55 and the length of the spring material 53 unwound from the winding portion 54a. This changes the load applied to the arm 51 by the spiral spring 52 via the weight 56 ​​in the clockwise direction in FIG. 4, i.e., the load in the direction that closes the flap valve 35, thereby adjusting the pressure difference (timing) at which the flap valve 35 switches from a closed state to an open state.

[0040] 10, when the winding member 54 is attached in a position where the center C1 of the winding portion 54a is located above the center C3 of the attachment portion 55, the unwound length of the spring material 53 is the shortest, and the biasing force of the spiral spring 52 on the flap valve 35 is the smallest (first attachment state). When the winding member 54 is attached in a position where the center C1 of the winding portion 54a is located to the right of the center C3 of the attachment portion 55, as shown by the dashed dotted line in FIG. 10, the unwound length of the spring material 53 is longer than in the first attachment state, and the biasing force of the spiral spring 52 on the flap valve 35 is greater than in the first attachment state (second attachment state). 10, when the winding member 54 is attached in a position where the center C1 of the winding portion 54a is located below the center C3 of the attachment portion 55, the unwound length of the spring material 53 is the longest, and the biasing force of the spiral spring 52 on the flap valve 35 is the greatest (third attachment state). When the spring material 53 is unwound in this third attachment state, the unwound portion becomes the linear portion 53b, and the biasing force becomes constant. In this way, in this embodiment, a constant-load spiral spring 52 is used as the biasing member, but the biasing force on the flap valve 35 can be finely adjusted within the range of the initial deflection by changing the attachment state.

[0041] 4 and 7, the weight 56 ​​is disk-shaped and is detachably attached to the first portion 51a of the arm 51 in Fig. 4. The weight 56 ​​applies a load to the arm 51 in a clockwise direction, that is, a load in a direction that closes the flap valve 35. A plurality of weights 56 with different weights are provided, and by replacing the weights 56 with weights of different weights, the pressure difference (timing) at which the flap valve 35 switches from a closed state to an open state can be adjusted.

[0042] The weight 56 ​​has an insertion hole 56a through which the arm 51 can be inserted, and is held by a well-known holding mechanism (not shown) so that it cannot fall off the arm 51. By changing the attachment position of the weight 56 ​​relative to the arm 51, that is, by changing the distance from the rotation shaft 37, the load on the flap valve 35 can be adjusted even with the same weight 56. The weight 56 ​​also has a screw hole (connection portion) 56b for mechanically connecting the spring material 53.

[0043] 4, the damper 57 has an upper end attached to the second portion 51b of the arm 51, which is the side opposite the weight 56, and a lower end attached to the horizontal pipe 21, and damps the vibration and amplitude of the flap valve 35 caused by opening and closing. The damper 57 in this embodiment is a damping member with adjustable damping force. However, the lower end of the damper 57 may be attached to the pump casing 12 or the installation floor 1, as long as it is a fixed rigid body. The damping member may be configured to provide Coulomb damping due to dynamic friction resistance, to provide viscous damping due to viscous resistance, or may be an elastic member. Any configuration can be used as long as it can damp the vibration of the flap valve 35 without interfering with the opening and closing of the flap valve 35.

[0044] Fig. 11 is a graph showing changes in pump performance of the vertical pump 10 of this embodiment. In Fig. 11, the horizontal axis is the ratio Q / Qopt of the flow rate Q to the optimum flow rate Qopt, and the vertical axis is the ratio H / Hopt of the head H to the optimum head Hopt. Although it depends on the specific speed, in Fig. 11, the region where Q / Qopt is less than approximately 70% is the partial flow rate region, the region where Q / Qopt is approximately 120% or more is the excessive flow rate region, and the range between these is the rated operation region. In normal operation, the motor 17 is controlled so that the pump is in the rated operation region or the excessive flow rate region, and in managed operation, the motor 17 is controlled so that the pump is in the partial flow rate region.

[0045] 11, Qb1 indicates the pump head H when the opening and closing timing of the flap valve 35 is adjusted only by the spiral spring 52. Qb2 indicates the pump head H when the opening and closing timing of the flap valve 35 is adjusted only by the weight 56. Qb3 indicates the pump head H when the opening and closing timing of the flap valve 35 is adjusted only by a general coil spring (not shown). The closing forces of all flap valves 35 using the spiral spring 52, the weight 56, and the coil spring are the same.

[0046] Referring to FIG. 11, when the pump is operated in the excessive flow rate range, the pump head H is lower than when the pump is operated in the partial flow rate range. Therefore, the pressure P in the discharge elbow 14 shown in FIG. 1 is lower than the pressure Pd in ​​the horizontal pipe 21 and the pressure Ps in the suction sump 2. As a result, the flap valve 35 is closed, and no pumped water is returned to the suction sump 2 through the bypass pipe 20. However, because the discharge flow rate Q increases, an air-sucking vortex may occur in the suction sump 2, where the water level drops due to drainage. However, in this embodiment, the vertical pipe 22 of the bypass pipe 20, which is arranged around the lifting pipe 13 as shown in FIG. 1, can suppress the occurrence of an air-sucking vortex. Therefore, the vertical pump 10 of this embodiment is capable of draining water in the excessive flow rate range during normal operation. During normal operation in the rated operating range, the discharge flow rate Q is lower than when the pump is operated in the excessive flow rate range, but stable drainage is possible.

[0047] When the pump is operated in the partial flow rate range, the pump head H is higher than when the pump is operated in the excessive flow rate range, and the pressure P in the discharge elbow 14 shown in FIG. 1 is higher than the pressure Pd in ​​the horizontal pipe 21 and the pressure Ps in the suction sump 2. As a result, when the pressure reaches or exceeds the return flow start head Hb, the flap valve 35 opens, and a portion of the pumped water is returned to the suction sump 2 through the bypass pipe 20. This causes a portion of the pumped water to be discharged through the bypass pipe 20 near the suction port 13a, thereby scooping up sludge at the bottom 3 of the suction sump 2 and discharging it using the vertical pump 10. This allows the interior of the suction sump 2 to be cleaned. Furthermore, without return flow through the bypass pipe 20, a backflow occurs at the inlet (suction port 13a side) of the impeller 16, which can cause cavitation and vibration. However, in this embodiment, a portion of the pumped water is returned through the bypass pipe 20, thereby suppressing backflow at the impeller 16. Therefore, in the vertical pump 10 of this embodiment, the operation of the impeller 16 from the partial flow rate region to the shutoff point is reduced, so the operating range in the small flow rate region can be expanded.

[0048] Referring to Qb3 in Figure 11, it can be seen that when a coil spring is used, the closing force (biasing force) of the coil spring increases in proportion to the opening degree even when the flap valve 35 is open, making it difficult to ensure the bypass flow rate. Referring to Qb1 in Figure 11, it can be seen that when a constant-load spiral spring 52 is used, the closing force (biasing force) becomes constant regardless of the opening degree after the flap valve 35 opens, making it easy to ensure the bypass flow rate. It can also be seen that by changing to a spiral spring 52 or coil spring with a different biasing force and changing to a weight 56 ​​with a different weight, it is possible to adjust the bypass start head Hb, and thereby adjust the bypass head Hb and bypass discharge rate Qb.

[0049] On the other hand, when inspecting the inside of the pump casing 12 of the vertical pump 10 of this embodiment, the motor 17 is stopped to stop operation. Then, as shown in FIG. 3, the eyebolt 29 is operated to open the door 26, and the arm 51 is operated to manually open the flap valve 35. In this state, a measuring device such as an endoscope is inserted into the pump casing 12 through the opening 25a, using the open flap valve 35 as a support. If the measuring device is unstable during insertion, a support base 60 with a U-shaped cross section can be placed on the door 26 as a dedicated guide jig (see FIG. 3). This allows for accurate inspection of the inside of the pump casing 12. Furthermore, by fixing the arm 51 with a rod or chain (not shown) and holding the flap valve 35 in an open position, the efficiency of inspection work using the measuring device can be improved.

[0050] The vertical pump 10 configured in this manner has the following features.

[0051] A flap valve 35 is attached to the bypass pipe 20, which can be rotated from a closed state to an open state when the pressure P inside the pump casing 12 becomes higher than the pressure Pd inside the bypass pipe 20. The pressure Pd inside the bypass pipe 20 becomes higher than the pressure P inside the pump casing 12 during normal operation for the purpose of drainage, and becomes lower than the pressure P inside the pump casing 12 during maintenance operation which is not intended for drainage. Therefore, the flap valve 35 is closed during normal operation and open during maintenance operation. The flap valve 35 does not require a drive source to switch between the open and closed states, which reduces the running costs of the pump equipment.

[0052] An adjustment mechanism 50 for adjusting the force that keeps the flap valve 35 closed is attached to the rotating shaft 37 of the flap valve 35, making it possible to adjust the pressure difference (timing) at which the flap valve 35 opens and closes. Therefore, the flap valve 35 can be reliably and automatically opened and closed according to the operating state, so that it switches to the closed state during normal operation and to the open state during maintenance operation.

[0053] An arm 51 is attached to the outer end of the rotating shaft 37 of the flap valve 35 that protrudes from the bypass pipe 20. Therefore, the flap valve 35 can be opened and closed manually by operating the arm 51. Therefore, a measuring instrument can be inserted from the horizontal pipe 21 to inspect the inside of the pump casing 12.

[0054] The adjustment mechanism 50 includes a spiral spring 52 that biases the flap valve 35 to the closed position via the arm 51 and the rotary shaft 37. Therefore, by using a spiral spring 52 with an appropriate biasing force, the timing at which the flap valve 35 opens and closes can be reliably adjusted. This allows the flap valve 35 to be reliably opened and closed automatically according to the operating conditions.

[0055] Because a constant-load spiral spring 52 is used, when a predetermined pressure difference is reached between the inside of the pump casing 12 and the inside of the bypass pipe 20 and the closed flap valve 35 switches to an open state, the opening angle of the flap valve 35, which is the valve opening degree, is maintained constant. Therefore, the amount of pumped water flowing out of the pump casing 12 can be maintained and secured constant during maintenance operation.

[0056] An attachment portion 55 for attaching the winding member 54 is provided on any one of the bypass pipe 20, the pump casing 12, or the installation floor 1 so that the unwinding length of the spring material 53 from the winding member 54 varies. The constant-load spiral spring 52 has an initial deflection, and the biasing force (load) gradually increases within the range of this initial deflection. Therefore, the pressure difference (timing) at which the flap valve 35 rotates can be adjusted by changing the position of the winding member 54 attached to the attachment portion 55. Therefore, the flap valve 35 can be automatically opened and closed reliably according to the operating state.

[0057] The adjustment mechanism 50 includes a weight 56 ​​that is detachably attached to the arm 51. Therefore, by using a weight 56 ​​of an appropriate weight, the timing at which the flap valve 35 opens and closes can be reliably adjusted. Therefore, the flap valve 35 can be reliably opened and closed automatically according to the operating conditions.

[0058] A damper 57 is attached to the arm 51 to dampen the vibration of the flap valve 35. This makes it possible to prevent chattering that occurs when the flap valve 35 opens and closes.

[0059] The bypass pipe 20 comprises a horizontal pipe 21 connected to the pump casing 12 and a vertical pipe 22 for discharging the outflowing pumped water into the suction tank 2. During normal operation, the flap valve 35 is switched to a closed state, which prevents the bypass pipe 20 from affecting the drainage water passing through the pump casing 12, allowing the water in the suction tank 2 to be efficiently discharged. Furthermore, the vertical pipe 22 arranged inside the suction tank 2 prevents the occurrence of air-sucking vortices that can occur inside the suction tank 2 during normal operation. During maintenance operation, the flap valve 35 is switched to an open state, which allows a portion of the pumped water to be returned to the suction tank 2 through the bypass pipe 20, allowing the area around the pump casing 12 to be cleaned (maintenance).

[0060] The end of the horizontal pipe 21 is closed by a door 26 that can be opened and closed. Therefore, by opening the door 26 and setting the flap valve 35 to the open state, it is possible to insert a measuring device such as an endoscope to inspect the inside of the pump casing 12. Since no pumping pressure is applied to the door 26 during normal operation, the durability required for the sealing structure of the door 26 can be reduced.

[0061] Because at least a portion of the door 26 is translucent, the open / closed state of the flap valve 35 can be easily confirmed through the door 26 during both normal operation and maintenance operation. In addition, during maintenance operation, the return state of a portion of the pumped water can be easily confirmed through the door 26.

[0062] A holding portion 28 is provided to hold the door 26 in an open position so as to extend along the axis of the horizontal pipe 21. This allows the door 26 to be used as a support base when inserting a measuring instrument from the horizontal pipe 21 of the bypass pipe 20 into the pump casing 12, thereby improving workability during inspection.

[0063] The present invention is not limited to the configuration of the above embodiment, and various modifications are possible.

[0064] For example, a tension spring may be used as the biasing member instead of the spiral spring 52. The biasing member may also be directly connected to the first portion 51a of the arm 51.

[0065] A plurality of mounting portions 55 may be provided at intervals in the vertical direction on horizontal pipe 21, so that the length of spring material 53 unwound from winding member 54 can be varied without changing the position of winding member 54 of spiral spring 52. In other words, mounting portion 55 can be changed as needed as long as it is configured to change the length of spring material 53 unwound from winding member 54.

[0066] A pipe for discharging a portion of the pumped water to a location other than the suction tank 2 may be connected to the bypass pipe 20. In this case, the bypass pipe 20 may be configured with only the horizontal pipe 21, without the vertical pipe 22 and the annular pipe 23. The vertical pipe 22 may be open at the top of the suction tank 2 without extending to the vicinity of the lower end of the pump casing 12.

[0067] The pump may be of any type as long as it has a cylindrical pump casing and an impeller for discharging water, and is configured to be switchable between normal operation and controlled operation. [Explanation of symbols]

[0068] 1 Installation floor 2 Water absorption tank 3 bottom 5 Discharge pipe 6. Gate valve 10 Vertical pump (pump) 12 Pump casing 13. Lifting pipe 13a Intake port 14 Discharge elbow 15 Rotation axis 16 impeller 17 Motor 18 Control Unit 20 Bypass pipe 21 Side piping (1st piping) 21a Inner end 21b Outer end 21c Connection 21d Cylinder part 21e Bearing section 21f Insertion part 22 Vertical piping (second piping) 22a Upper end (1st end) 22b Lower end (2nd end) 23 Circular piping (third piping) 23a Nozzle 24 Lid 25 Mounting plate 25a opening 26 Door 27 Hinge 28 Holding part 29 Eyebolt 30 Bracket 35 Flap valve 36 Valve body 37 Rotation axis 38 Movable valve seat 39 Fixed valve seat 40 sealing material 41 Ball bearings 42 Bearing material 50 Adjustment mechanism 51 Arm 51a Part 1 51b Part 2 52 Power spring (biasing member) 53 Spring material 53a Tip 53b Linear part 53c Connection hole 54 Winding member 54a Winding section 54b Mounting flange 54c Mounting hole 55 Mounting part 55a bolt hole 56 Weight 56a Insertion hole 56b screw hole 57 Damper (damping material) 60 Support stand

Claims

1. a cylindrical pump casing partially disposed within the suction tank; an impeller rotatably disposed within the pump casing for discharging water from the suction tank; a bypass pipe arranged outside the pump casing, branched and connected to the pump casing downstream of the impeller, for allowing a portion of the pumped water discharged through the pump casing to flow out of the pump casing; a flap valve having a rotating shaft rotatably supported on the bypass pipe, and which is rotatable in a direction away from the pump casing from a closed state in which the outflow of the pumped water is blocked to an open state in which the outflow of the pumped water is allowed when the pressure in the pump casing becomes higher than the pressure in the bypass pipe; an adjustment mechanism attached to the rotary shaft for adjusting the force that maintains the flap valve in the closed state; Equipped with At least one end of the rotating shaft penetrates the bypass pipe and protrudes to the outside, an arm is provided at the one end of the rotation shaft, The adjustment mechanism includes a biasing member formed by a constant-load spiral spring connected to the arm and biasing the flap valve to a closed position via the arm and the rotating shaft.

2. the power spring includes a strip-shaped spring material connected to the arm and a winding member that winds up the spring material so that the spring material can be unwound, any one of the bypass pipe, the pump casing, and an installation floor to which the pump casing is fixed includes an attachment portion for attaching the winding member; The mounting portion is changeable to a plurality of mounting states having different unwinding lengths of the spring material from the winding member.

2. The pump of claim 1.

3. The pump of claim 1 or 2, wherein the adjustment mechanism comprises a weight removably attached to the arm.

4. 3. The pump according to claim 1, wherein a damping member is attached to the arm to damp vibration of the flap valve.

5. The bypass pipe is a first pipe extending in a direction intersecting the pump casing; a second pipe having a first end branched and connected to the first pipe and a second end disposed within the suction tank, for discharging the outflowing pumped water into the suction tank; Equipped with The pump according to claim 1 or 2, wherein the flap valve is disposed in the first pipe between the first end of the second pipe and the pump casing.

6. The pump according to claim 5 , wherein an end of the first pipe opposite to the pump casing is closed by a door having at least a portion that is translucent and that can be opened and closed.

Images