JP3058365B2 - Vertical pump - Google Patents

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, and more particularly to a vertical shaft pump suitable for, for example, a preliminary standby operation of a rainwater drainage pump station.

[0002]

2. Description of the Related Art In recent years, due to an increase in a rainwater impervious area due to an increase in the pavement rate of roads, a sudden inflow of rainwater into a rainwater drainage pumping station called an urban flood has become a problem.
For this reason, in order to prepare for a sudden rise in the water level of the pump pit during rainfall, a precedence standby operation pump that operates the pump from a state where the water level of the pump pit is lower than the specified water level has been put to practical use. Examples of the technology relating to such a preceding standby operation pump include those described in Japanese Utility Model Laid-Open No. Sho 62-28097 and Japanese Utility Model Laid-Open No. Sho 63-150097.

[0003]

SUMMARY OF THE INVENTION In order to start the operation of the vertical stand-by vertical pump before the pump pit reaches the pumpable water level, it is necessary to operate the pump in a state where there is no water in the pump. Is done. That is, since the pump is idled in the atmosphere, there is no supply of water for assisting lubrication to the bearing portion. For this reason, a water supply device for supplying water to the bearing portion has been provided, or a ceramic bearing using a material operable in a state of no water supply without water has been employed.

However, providing a water supply device has a problem that the equipment becomes complicated. In addition, there is a problem that the application of the ceramic bearing that can be operated without water supply is limited by the load applied to the sliding surface and the peripheral speed of the sliding portion, and in some cases, the application is not possible. In addition, when the water level of the pump pit rises and the pump enters a stirring operation state while sucking air, the fluid force is more likely to be unbalanced than in the idling state in the atmosphere, and the vibration caused by the unbalance is caused. There was a problem that occurs.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and it is possible to expand the application of a waterless bearing during idling operation in a waterless state.
It is an object of the present invention to provide a vertical shaft pump for a preliminary standby operation that can ensure reliability and at the same time reduce vibration.

[0006]

Means for Solving the Problems To achieve the above object, a first aspect of the invention relates to a vertical shaft pump of the present invention, wherein a main shaft for rotating an impeller is supported by a bearing fixed by a casing, Has a bell mouth as the suction side casing,
In a vertical shaft pump in which an intake hole is provided in a casing below an impeller and an intake pipe is connected to the intake hole, a shaft relatively thinner than a shaft diameter of a main shaft of the pump below the tip of the impeller boss. An auxiliary shaft having a diameter extending concentrically with the main shaft, a water-supply-free bearing supporting the auxiliary shaft is provided near a lower end in a bell mouth, and a gap between the main shaft and the bearing supporting the main shaft is provided. Is relatively larger than the gap between the auxiliary shaft and a bearing that supports the auxiliary shaft.

In a second aspect of the vertical shaft pump according to the present invention, a main shaft for rotating the impeller is supported by a bearing fixed by a casing, and a bell mouth is provided as a suction side casing. In a vertical shaft pump having an intake hole provided in a casing below and having an intake pipe connected to the intake hole, a shaft diameter relatively smaller than the shaft diameter of the main shaft of the pump is provided below the tip of the impeller boss. The auxiliary shaft is provided to extend concentrically with the main shaft, and a waterless operable bearing that supports the auxiliary shaft is provided outside the lower end of the bell mouth, and a gap between the main shaft and the bearing that supports the main shaft, The gap is relatively larger than the gap between the auxiliary shaft and a bearing that supports the auxiliary shaft. Further, the support portion for supporting the bearing of the auxiliary shaft on the bell mouth is configured as a rectifying plate for rectifying the flow flowing from the bell mouth to the impeller.

[0008]

The function of the above technical means is as follows. Since the auxiliary shaft and auxiliary shaft bearing installed below the impeller boss are relatively thinner than the main shaft, the peripheral speed of the auxiliary shaft bearing sliding surface is lower than that of the main shaft bearing sliding surface. Has become. Thereby, even when a waterless bearing cannot be applied at the peripheral speed of the shaft diameter of the main shaft, a waterless bearing can be applied as the auxiliary bearing.

When the water level in the pump pit is lower than that of the bellmouth, the fluid force is unbalanced in the idling state in the atmosphere during the preparatory standby operation. Load is small. On the other hand, at this time, in the bearing of the main shaft, there is no contact between the sliding surfaces because the clearance between the shaft and the bearing is large. That is, in the idling state in the atmosphere, the auxiliary shaft bearing acts as a bearing of the pump, and does not act as a bearing on the main shaft bearing.
Therefore, the reliability of the bearing at the time of idling at a low water level in which the bearing is in a water-free state is improved.

[0010] When the water level in the pump pit rises and the vertical shaft pump is in a stirring operation while sucking air, water is supplied to the auxiliary shaft bearing and the main shaft bearing, so that the water is no longer supplied. Further, vibration occurs due to the imbalance of the fluid force in the mixed state of water and air, but both the main shaft bearing and the auxiliary shaft bearing act as bearings, and the vibration is suppressed. That is, when the auxiliary shaft and the auxiliary shaft bearing are not installed as in the related art, the impeller is supported on one side on the back side of the impeller, which is a so-called cantilever state. Vibration is easy to come out,
In the present invention, by installing the auxiliary shaft and the auxiliary shaft bearing, the impeller is supported on both the front surface and the rear surface, and the vibration is suppressed.

When the water level in the pump pit further rises and the vertical shaft pump is in a draining operation state of only water, the same operation as in the stirring operation state is performed. Further, if the support structure of the auxiliary shaft bearing is a rectifying plate, the flow of water sucked from the bell mouth can be stabilized, and vibration can be reduced.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. [Embodiment 1] FIG. 1 is a sectional view showing a ball portion of a vertical shaft pump for a preliminary standby operation according to an embodiment of the present invention. As shown in FIG. 1, a boss 1a of the impeller 1 is fitted, and a main shaft 8 driven by a motor (not shown) provided on an upper portion.
Is supported by a main shaft bearing 9 fixed to the inner wall side of the pump casing 4 via a main shaft bearing stay 7. Below the casing liner 2 of the pump casing 4 containing the impeller 1, a bell mouth 3 is connected as a suction side casing.

The boss 1a of the impeller 1 is concentric with the main shaft 8.
An auxiliary shaft 10 extends downward from the distal end. The auxiliary shaft 10 is supported by an auxiliary shaft bearing 11 fixed to the inner wall of the bell mouth 3 via an auxiliary shaft bearing stay 12.
An intake hole 5 is opened near the lower part of the impeller 1 (the bell mouth 3 in the example of FIG. 1), and an intake pipe 6 indicated by a dashed line is connected to the intake hole 5. Is provided with an intake air amount adjusting valve, and constitutes a flow control device.

The diameter of the auxiliary shaft 10 is smaller than that of the main shaft 8 to such an extent that there is no problem in strength. Auxiliary shaft bearing 11
Is a bearing that can be operated without water supply, such as a ceramic bearing, for example. Further, the gap between the main shaft bearing 9 and the main shaft 8 is such that the sliding surface is in contact with the whirling that occurs when the pump idles in the atmosphere while the auxiliary shaft 10 is supported by the auxiliary shaft bearing 11. It is set not to be. The operation of the vertical stand-by pump for standby operation will be described below.

When it is predicted that rapid rainwater flows into the drainage pump station due to rainfall, the vertical shaft pump shown in FIG. 1 is at a lower water level than the drainage start water level Ld, and the water level of the pump pit is still at the lower end of the bell mouth 3. , Start idling of the pump in the atmosphere. At this time, the auxiliary shaft bearing 11 is in a non-water-supplied state. However, since the bearing is basically a bearing capable of water-free operation and the shaft diameter of the auxiliary shaft 10 is smaller than the shaft diameter of the main shaft 8, the auxiliary shaft bearing 11 is not supplied with water. Since the peripheral speed of the sliding portion of the bearing 11 is low and the operation is performed in the air, the load on the auxiliary shaft bearing 11 due to the unbalance of the fluid force is small. . On the other hand, in the main shaft bearing 9, since the gap between the main shaft 8 and the main shaft 8 is set large as described above, there is no contact of the sliding surface, the main shaft bearing 9 does not function as a bearing, and the auxiliary shaft bearing 11 functions as a bearing. Then, the idling state can be continued.

When the water level in the pump pit rises and the vertical pump enters the agitating operation state while sucking air from the intake hole 5 through the intake pipe 6, a small amount of water is pumped in a mixed state of air and water, and Are the auxiliary shaft bearing 11 and the main shaft bearing 9
Both are in a water supply state and act as bearings.
Thereafter, when the water level further rises and reaches the drainage start water level Ld, a normal water only drainage operation state is established, and the bearing is supplied with water. In the stirring operation state and the normal drainage state, the imbalance of the fluid force is greater than in the idling state in the air, but the main bearing 9 suppresses the runout due to the imbalance. Further, since the auxiliary shaft 10 is provided, the vibration is restricted, and an effect of suppressing the vibration as compared with the case where the auxiliary shaft 10 is not provided can be expected.

Conversely, considering the case where the water level falls from the water level where the pump pit is in a normal drainage state,
Up to the drainage stop water level Ls, the auxiliary shaft bearing 11 and the main shaft bearing 9 support rotation in a water supply state. When the water level reaches the drain stop water level Ls, the pump is not drained, and the main shaft bearing 9 is in a non-water supply state. However, since the impeller 1 is already idling in the air, the influence of the imbalance of the fluid force is not affected. Since the bearing is small and the runout is small, there is no contact of the sliding surface of the spindle bearing 9. At this time, the main shaft bearing 9 does not act as a bearing. The auxiliary shaft bearing 11 is still in the water and can continue to idle without any trouble, and then continues to idle until it further falls to the prescribed shutdown water level.

[Embodiment 2] FIG. 2 is a sectional view showing a ball portion of a vertical shaft pump for preceding standby operation according to another embodiment of the present invention. In the figure, components having the same reference numerals as those in FIG. 1 are the same as those in the previous embodiment, and the description thereof will be omitted. In the embodiment shown in FIG. 2, an auxiliary shaft 10A having a shaft diameter relatively smaller than the shaft diameter of the main shaft 8 of the pump is provided below the tip of the impeller boss 1a so as to extend concentrically with the main shaft 8, An auxiliary shaft bearing 11A that supports the auxiliary shaft 10A and can be operated without water supply is provided outside the lower end of the bell mouth 3.
The auxiliary shaft bearing 11A is fixed to the outer end of the bell mouth 3 via an auxiliary shaft bearing stay 12A. According to the embodiment of FIG. 2, the same effects as those of the embodiment of FIG.
The auxiliary shaft bearing 11A has an effect unique to the present embodiment that it can increase the chances of being immersed in water and reduce the non-water supply operation state.

[Embodiment 3] FIG. 3 is a sectional view showing a ball portion of a vertical shaft pump for a preliminary standby operation according to still another embodiment of the present invention. In the figure, components having the same reference numerals as those in FIG. 1 are the same as those in the previous embodiment, and the description thereof will be omitted. The embodiment of FIG. 3 is different from the embodiment of FIG. 1 in that the auxiliary shaft bearing stay is configured as a rectifying plate 13 to rectify the flow of water sucked from the bell mouth 3 and to reduce the generation of vibration due to turbulence of the flow. It is to suppress. According to the embodiment of FIG. 3, the same effect as that of the embodiment of FIG. 1 can be obtained. In addition, the auxiliary shaft bearing stay 12A rectifies the flow of water sucked from the bell mouth 3 to suppress the generation of vibration. There are effects specific to the embodiment.

[0020]

As described above in detail, according to the present invention, it is possible to expand the application of the waterless bearing in the idling operation in the waterless state, to secure the reliability, and at the same time to ensure the vibration reduction. It is possible to provide a vertical shaft pump for a preliminary standby operation that can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a ball portion of a vertical shaft pump for preceding standby operation according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a ball portion of a vertical shaft pump for preceding standby operation according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a ball portion of a vertical stand-by pump for vertical standby operation according to still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Impeller 1a Boss 2 Casing liner 3 Bell mouth 4 Pump casing 5 Intake hole 6 Intake pipe 8 Main shaft 9 Main shaft bearing 10, 10A Auxiliary shaft 11, 11A Auxiliary shaft bearing 12, 12A Auxiliary shaft bearing stay 13 Rectifier plate

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A 1-1141393 (JP, U) JP-A 1-130094 (JP, U) JP-63-150097 (JP, U) JP-63 121798 (JP, U) Japanese Utility Model 62-28097 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04D 13/00 F04D 15/00

Claims (3)

(57) [Claims] 1. A main shaft for rotating an impeller is supported by a bearing fixed by a casing, a bell mouth is provided as a suction side casing, an intake hole is provided in a casing below the impeller, and an intake hole is provided in the intake hole. In a vertical shaft pump having a pipe connected thereto, an auxiliary shaft having a shaft diameter relatively smaller than the shaft diameter of the main shaft of the pump is provided below the tip of the impeller boss so as to extend concentrically with the main shaft, and the auxiliary shaft is provided. A water-supply-free bearing that supports the shaft is provided near the lower end in the bell mouth, and a gap between the main shaft and the bearing that supports the main shaft is larger than a gap between the auxiliary shaft and the bearing that supports the auxiliary shaft. Vertical pump characterized in that it is also relatively large. 2. A main shaft for rotating an impeller is supported by a bearing fixed by a casing, a bell mouth is provided as a suction side casing, an intake hole is provided in a casing below the impeller, and an intake hole is provided in the intake hole. In a vertical shaft pump having a pipe connected thereto, an auxiliary shaft having a shaft diameter relatively smaller than the shaft diameter of the main shaft of the pump is provided below the tip of the impeller boss so as to extend concentrically with the main shaft, and the auxiliary shaft is provided. A waterless operable bearing that supports the shaft is provided outside the lower end of the bell mouth, and a gap between the main shaft and the bearing that supports the main shaft is larger than a gap between the auxiliary shaft and the bearing that supports the auxiliary shaft. A vertical pump characterized by being relatively large. 3. A rectifying plate for rectifying a flow flowing from the bell mouth to the impeller, wherein the supporting portion for supporting the bearing of the auxiliary shaft on the bell mouth is configured. Any vertical pump.