JPH11159491A - Pull-out vertical pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vertical pump capable of preventing vibration generated during intake operation, reducing a pump load on a pump installing floor and reducing a construction cost on site, like a suction type preceding waiting operation pump. SOLUTION: In a pull-out vertical pump housed inside a feed water tank and provided with a suction bell-mouth 3 and a suction casing 4, a pump hydraulic unit comprising an impeller 1, a casing liner 2, a guide vane casing 5, a discharge diffuser 6 and a pump shaft 9 is configured to be freely drawn upward in the axial direction of the pump from the discharge casing 7 containing the pump hydraulic unit therein, wherein the suction bell-mouth 3, the suction casing 4 and the discharge casing 7 are fixed to the feed water tank.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical shaft pump installed in a water absorption tank, and more particularly to a vertical shaft pump applicable to, for example, a preceding standby operation pump for draining water during rainfall.

[0002]

2. Description of the Related Art With the recent urbanization, the amount of rainwater flowing into a drainage pumping station has rapidly increased due to an increase in rainwater impervious area. For this reason, in the case of rainfall, a preliminary standby operation type vertical shaft pump that predicts the amount of water flowing into the pump station and the arrival time in advance and operates the pump from a state where the pump suction tank water level is lower than a specified water level has been put to practical use.

Conventionally, this type of vertical pump is disclosed in Japanese Patent Application Laid-Open No. 63-906.
As described in Japanese Patent Publication No. 97, when the water level at the time of submersion of the pump is lower than this, the impeller is set at a position slightly higher than a specific pump specific portion corresponding to the lowest water level (LWL) at which air is sucked. In some cases, when the water level becomes lower than the water level corresponding to the minimum water level, a vacuum break occurs to make the wheel idle, and the water is dropped to prevent the drainage operation.

As another conventional vertical shaft pump, as described in Japanese Utility Model Application Laid-Open No. 63-150097, an impeller is located at a position lower than the water level of a water absorption tank, and an external pump is provided near an inlet of the impeller. It is known that a through-hole is provided to connect to a pipe, and the through-hole is connected to a pipe, and the other end of the pipe is provided with an opening near a level where the impeller in the water absorption tank is submerged.

Further, as another example, there is one described in Japanese Patent Application Laid-Open No. 4-103895. This is because the vertical shaft pump may generate vibration during the preliminary standby operation of the pump, and a damper is attached to the bell mouth to prevent the vibration.

[0006]

In the above prior art, no consideration is given to the following points.

That is, the pump may vibrate during the intake operation in the preliminary standby operation or during the operation near the pumping stop water level. This is because the gaseous mixed water flows in the pump in a non-uniform manner due to the water level and flow rate of the water absorption tank, and the fluid imbalance force acting on the impeller increases, causing vibration to the pump. JP-A-63-90697 published and Japanese Utility Model 63-150
It is generally difficult to avoid such vibrations in the technology disclosed in Japanese Patent No. 097. As a countermeasure against this,
In Japanese Patent No. 103895, a heavy damper is attached to a suction bell mouth to suppress vibration generated in a pump. However, since the damping body increases the weight of the pump body with heavy parts,
It increases pump manufacturing costs, increases the floor load at the pump installation site of the pump station, and impairs workability in transportation and assembly.

On the other hand, when the pump is removed from the pump well for repair or inspection of the inside of the pump, it is necessary to pull up the entire pump from the water absorption tank in the conventional vertical shaft pump. Since the entire pump is raised, the number of work steps is large, and there is a problem that the cost required for removal is large.

It is an object of the present invention to provide a vertical shaft pump which facilitates removal of the pump for repair and inspection of the pump, suppresses vibration generated in the preceding standby pump, and reduces the floor load on the pump. Aim.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a pull-out type vertical shaft pump having a suction bell mouth and a suction casing, which is installed in a water absorption tank, and has an impeller, a casing liner, a guide blade casing, a discharge diffuser and a pump. A pump hydraulic part having a shaft is structured so as to be able to be drawn out from a pump discharge casing storing the pump hydraulic part upward in the pump axial direction, and the suction bell mouth, the suction casing and the discharge casing are fixed to a water suction tank. Achieved by

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a vertical pump, and FIG.
FIG. In the figure, an impeller 1 has a pump shaft 9.
The casing liner 2 is attached to the guide vane casing 5 outside the impeller 1. Downstream of the guide blade casing 5, a discharge diffuser 6 for recovering the pressure of the discharge flow from the guide blade is attached. The pump shaft 9 includes a submerged bearing 11 and an upper thrust bearing 12.
Supported by The pump shaft 9 is connected to a prime mover (not shown) via a shaft coupling 13. The thrust bearing 12 and the shaft sealing device 14 are housed in a bearing bracket 15. The protection tube 10 of the pump shaft 9 is a bearing bracket 15
And the discharge diffuser 6 and the guide blade casing 5. A rotating body composed of the impeller 1 and the pump shaft 9, a pump shaft protection tube 10, bearings 11, 1
The rotating body support portion including the bearing 2 and the bearing bracket 15, the casing liner 2, the guide blade casing 5, and the discharge diffuser 6 are integrally combined (hereinafter, this integrated portion is referred to as a pull-out portion), and have a cylindrical shape. Is separated from the discharge casing 7 of FIG. The discharge casing 7 is supported on the upper wall 19a of the water absorption tank 19 by a base 22 and a support 23 provided at a necessary position on the circumference. The discharge casing 7 is provided with a discharge port 7c in a direction perpendicular to the pump shaft 9, and a discharge pipe (not shown) is connected to the discharge port 7c.

On the other hand, an inner lower end 7b of the discharge casing 7, which is a fixed portion, is provided with a mounting seat 7b having a concave conical surface having a lower apex. As shown in the detailed cross-sectional view of FIG. 3, a convex conical surface 2a fitted to the conical mounting seat 7b is formed outside the casing liner 2 at the lower end of the pull-out portion. The conical surface 2a and the conical seat 7b of the casing liner 2 are automatically aligned with the center of the casing liner 2 and the center of the discharge casing 7 by the weight of the pull-out portion.
1 seals the water between both sides. Therefore, the pressure water in the discharge casing does not leak to the suction casing side.

A suction casing 4 and a suction bell mouth 3 below the suction casing 4 are attached to a lower end outside the discharge casing 7 by a flange joint. Two suction pipes 8a and 8b are attached to the side surface of the suction casing 4 so that air can be sucked into the suction pipe from outside through the suction holes 16a and 16b. Above each of the intake pipes 8a and 8b, an intake air amount adjusting valve 17 is provided, and an intake port 18 is installed at a position higher than the highest water level (HWL) in the water absorption tank, and these constitute a flow control device. I have. Intake holes 16a, 16b
Is provided at a position which is not sucked through the intake holes 16a and 16b at the conventional lowest water level, that is, at the lowest water level (WL1) below which the air is sucked from the suction bell mouth. Further, rectifying plates 20a, 20b, 20c, and 20d arranged radially are provided between the lower surface of the suction bell mouth of the pump and the bottom surface 19c of the suction tank so that the pump load can be applied to the bottom surface 19C of the strong absorption tank.
And the flow flowing into the pump suction casing 4 is rectified.

Now, the inflow of rainwater into the water absorption tank 19 starts, and when the water level reaches LW1, pumping starts from the pump. Further, even if the amount of water flowing into the water absorption tank 19 increases and the water level rises to WL4, pumping continues smoothly. Next, when the amount of inflow into the suction tank decreases and the water level starts to decrease, when the water level reaches WL1, suction from the suction holes 16a and 16b to the pump is started. Further, as the water level decreases, the amount of intake air increases, and when the water level reaches a certain water level WL3, the pump becomes unable to pump water, and the impeller 1 is in an idle state in which the upper part of the impeller is full of water but the lower side has no water. Thereafter, the water level rises again and the water level becomes W
When the pump reaches L2, the pump again performs the suction operation, and when the inflow is larger than the pumping amount, the water level continues to rise, and WL
When it reaches 1, the intake is stopped, and the operation shifts to the normal pumping operation.

As described above, in this embodiment, even when the water level in the water absorption tank 19 is low, the flow rate is automatically adjusted by sucking into the pump through the intake holes 16a and 16b, and the preceding standby operation is performed. In the intake operation state during the preceding standby operation, for example, when the flow rate is small and the intake air amount is large, the distribution of bubbles in the impeller 1 becomes uneven, and the flow of water in the impeller 1 becomes uneven, and the impeller 1 1 generates a fluid unbalance force,
May cause vibration to the pump. However, in the pump of the present embodiment shown in FIG. 1, the suction bell mouth 3 and the bottom surface 19c of the water absorption tank are firmly connected to the straightening plates 20a, 20b, 20c, 20c.
Since it is connected by d, it is possible to prevent the vibration that may occur during the above-described intake operation, and to perform a quiet and stable intake operation. Furthermore, the above-mentioned flow straightening plates 20a, 20b, 20c, and 20d enhance the circumferential uniformity of the flow to the suction casing 4, suppress the generation of the suction vortex, and make the flow at the impeller inlet uniform. For,
This results in improved pump efficiency. On the other hand, since the pump body is divided into a fixed portion centering on the discharge casing 7 and a pull-out portion centering on the pump hydraulic portion, the pump casing is fixed when the pump is inspected or repaired. Only the pull-out part can be pulled out, and workability is extremely improved. Therefore, it is possible to solve the problem of the occurrence of vibration, which was conventionally a bottleneck during the preliminary standby operation, and at the same time, it is possible to greatly reduce the pump load acting on the pump installation floor 19a. Construction costs can be reduced.

Next, a second embodiment is shown in FIG. In the present embodiment, a support member 20e for connecting the suction bell mass 3 of the pump shown in FIG.
~ Several places. The support member 20e is fixed to the outer peripheral surface of the bellmass 3 and the side wall 19b by bolts. Since the pump and the water absorption tank wall 19b are firmly connected to each other by the support member 20e, even if a large unbalance force is generated in the impeller 1, the generation of vibration is suppressed and a quiet operation becomes possible.

FIG. 5 shows a third embodiment. In this embodiment, the support of the suction bellmass 3, the suction casing 4, the side surfaces of the discharge casing 7, and the water absorbing tank wall surface 19b, which are fixed bodies of the pump shown in FIG. doing. In this case, the second
In the same manner as in the embodiment, it is possible to suppress the vibration of the pump which may be generated during the intake operation and the like, and to rectify the flow in the gap between the pump and the water absorption tank 19, thereby to make the air suction vortex or the underwater vortex. Can also be prevented from occurring. as a result,
More quiet and stable operation is possible.

Further, when replacing a pump at an old pumping station where the floor load is set low, it is possible to replace the pump with a pump having a larger own weight than a conventional pump.

It is apparent from the above description that the present invention can be applied not only to the preceding standby pump but also to a general vertical pump.

[0021]

According to the present invention, the following effects can be obtained. (1) Because of the pull-out type, workability such as installation and disassembly of the pump is improved.

(2) Since the suction bell mouth, the suction casing, and the discharge casing can be firmly fixed to the water suction tank and the pump floor, vibration of the pump which may occur during the suction operation can be suppressed.

(3) If a radial straightening plate is provided between the suction bell mouth and the bottom surface of the water absorbing tank, the straightening plate bears the pump load, so that the floor load of the pump can be reduced. As a result, a larger pump can be installed when the construction cost of the pump station is reduced or when the pump at the pump station is renewed. Further, the rectifying action of the rectifying plate can suppress the generation of the suction vortex and improve the efficiency of the pump.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.

FIG. 2 is a view as seen from an arrow A of the embodiment of FIG. 1;

FIG. 3 is a detailed longitudinal sectional view showing a fitting portion of a fixed portion and a pull-out portion of the pump according to the embodiment of the present invention.

FIG. 4 is a longitudinal sectional view showing a second embodiment of the present invention.

FIG. 5 is a longitudinal sectional view showing a third embodiment of the present invention.

[Explanation of symbols]

1: impeller, 2: casing liner, 3: suction bell mouth, 4: suction casing, 5: guide blade casing,
6: discharge diffuser, 7: discharge casing, 8: intake pipe, 9: pump shaft, 10: pump shaft protection tube, 11: underwater bearing, 12: thrust bearing, 13: shaft coupling, 14: shaft sealing device, 15: Bearing bracket, 16: intake hole, 17: intake amount control valve, 18: intake port, 19: water absorption tank, 20a, 2
0b, 20c, 20d, 20e, 20f: support material, 2
1: round rubber packing, 22: base, 23: support.

Claims (6)

[Claims] 1. A pull-out vertical shaft pump having a suction bell mouth and a suction casing installed in a water absorption tank, comprising an impeller, a casing liner, a guide blade casing,
A pump hydraulic part including a discharge diffuser and a pump shaft is configured to be able to be drawn out from a pump discharge casing storing the pump hydraulic part to an upper part in a pump shaft direction, and the suction bell mouth, the suction casing and the discharge casing are provided in a water absorption tank. A pull-out vertical pump characterized by being fixed. 2. A pull-out type vertical pump according to claim 1, wherein a straightening plate is radially arranged and fixed between a lower surface of the suction bell mouth and a bottom surface of the water absorption tank. . 3. A pull-out type vertical pump according to claim 1, wherein one of the suction bell mouth and the suction casing is connected to a side wall of the water absorption tank or a bottom surface of the water absorption tank by a support material. . 4. A pull-out type vertical shaft pump according to claim 1, wherein the plane of the supporting member is within a plane formed by the pump shaft and a surface perpendicular to a side wall surface opposite to the inflow side of the water absorption tank with respect to the pump. A pull-out type vertical pump characterized by providing a support material as described above. 5. The pull-out type vertical shaft pump according to claim 1, wherein an outer periphery of a casing liner at a lower end of the pump hydraulic portion is formed in a conical surface, and a conical seat is formed on an inner periphery of a lower end of the discharge casing. A pull-out type vertical shaft pump characterized in that a conical surface and a conical seat on the inner periphery of the lower end of the discharge casing are fitted together by the weight of the hydraulic part of the pump to obtain centering and water sealing functions of the pump. 6. A pull-out vertical shaft pump having a suction bell mouth and a suction casing installed in a water absorption tank, comprising: an impeller, a casing liner, a guide blade casing;
A pump hydraulic part including a discharge diffuser and a pump shaft is configured to be able to be drawn out from a pump discharge casing storing the pump hydraulic part to an upper part in a pump shaft direction, and the suction bell mouth, the suction casing and the discharge casing are provided in a water absorption tank. The pump is fixed, and a pump impeller provided below a position corresponding to a minimum water level at which water is sucked from a suction bell mouth of the pump casing when the water level during the operation of the pump is lower than the pump impeller; And a suction pipe connecting one end to the suction hole and opening the other end to the atmosphere at a level higher than the maximum water level of the pump suction tank. A pull-out type vertical shaft pump characterized by the above-mentioned.