JP3647956B2 - Vertical shaft pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vertical shaft pump, and more particularly to a ceramic bearing lubrication and cooling device for a vertical shaft pump in which a lower end portion of an impeller shaft is supported by a ceramic bearing.
[0002]
[Prior art]
Conventionally, vertical shaft pumps have been widely used in rainwater drainage stations.
By the way, a ceramic bearing tends to be used for the impeller side bearing of this vertical shaft pump.
On the other hand, in recent years, drainage stations in urban areas have a rapid inflow of rainwater into the rainwater drainage station due to local heavy rain due to heat islands and a decline in rainwater absorption capacity due to asphalt on roads. It tends to be large.
In order to cope with this, a so-called pre-standby operation, in which the pump is made to wait in advance in an operating state in anticipation of rainfall, is increasing.
However, during the preceding standby operation, since the amount of rainwater flowing into the water tank is small, the dry operation will be performed for a long time. However, if this dry operation becomes longer, the ceramic bearing will be damaged by heat generation. It is necessary to supply lubricating water to the ceramic bearing from the outside during operation.
For this reason, there have been proposed a method of supplying lubricating water directly to the ceramic bearing from the outside and a method of supplying water to a part of the ceramic bearing device of the pump and supplying the lubricating water therefrom.
[0003]
[Problems to be solved by the invention]
However, in the former method, since an external water supply pipe is required, the maintenance thereof is necessary, and in the latter method, there is a risk that the amount of water cannot be increased so much that there is a risk of lack of lubricating water.
It is an object of the present invention to provide a vertical pump that lubricates and cools a ceramic bearing with this water storage by making the protective tube function as a water storage tank, focusing on the fact that the volume of the protective tube is large in the vertical shaft pump. .
[0004]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a vertical shaft pump in which a lower end portion of an impeller shaft is supported by a ceramic bearing provided in a vane casing, and the vane casing and the impeller shaft pass through an impeller shaft extending above the vane casing. A protection pipe provided between the bent part of the pumping pipe and a pumping water inlet provided on the upper part of the protection pipe, and a shaft sealing device provided below the ceramic bearing of the vane casing. A chamber formed between the apparatus and the ceramic bearing is communicated with a lower portion of the pumped water inlet by a circulation pipe, and a liquid circulation mechanism is provided on the impeller shaft in the protection pipe.
A strainer may be provided at the pumped water inlet.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a vertical shaft of the present invention, wherein 1 is a pumping pipe having an upper part bent, 4 is an impeller shaft having an upper end penetrating a bent portion 2 of the pumping pipe 1 and an impeller 5 at a lower end. The upper end is supported by a bearing 6 and the lower end is supported by a ceramic bearing 8 provided on the vane casing 3 of the pumped-up pipe 1. As shown in FIG. 3, the ceramic bearing 8 is provided with a large number of holes H for passing lubricating water, as in the ceramic bearing 11 described below.
Moreover, the part exposed to the pumping path P of the impeller shaft 4 is in the protective pipe 10 provided between the bent portion 2 of the vane casing 3 and the pumping pipe 1, and damage due to foreign matters in the pumped water is prevented. . In addition, the intermediate part with the impeller shaft 4 is supported by a ceramic bearing 11 provided at substantially the center of the protective tube 10.
[0006]
On the other hand, a pumping water inlet 12 made up of a large number of small holes is provided in the upper part of the protective tube 10, and a shaft such as a mechanical seal or a ground packing device is provided between the lower end inner wall of the vane casing 3 and the impeller shaft 4. A sealing device 9 is provided, and a chamber 13 formed by the ceramic bearing 8 and the shaft sealing device 9 and a portion below the pumped water inlet 12 are communicated by a circulation pipe 14. Further, the impeller shaft 4 slightly above the ceramic bearing 8 is provided with an impeller 15 which is one of liquid circulation mechanisms for moving the water in the protective tube 10 downward by the rotation of the impeller shaft 4. In addition, 7 is a shaft seal device.
[0007]
Since the vertical shaft pump according to the present invention has the above-described configuration, first, circulating water is supplied into the protective tube 10 by some external water injection device or the like. Alternatively, this water supply may be automatically performed by actually pumping the pump.
[0008]
As described above, since a large amount of lubricating water is stored in the protective tube 10, the ceramic bearings 8 and 11 are always immersed in the lubricating water even when the dry operation based on the preceding standby operation is performed after a long time. In addition, since the lubricating water in the protective tube 10 is circulated by the impeller 15 via the circulation pipe 14 and cooled during that time, the ceramic bearings 8 and 11 are not burned out. Further, during the pump operation, water in the protective tube 10 is forcibly distributed by the impeller 14, so that foreign matters such as sand do not accumulate near the ceramic bearing 8, and abnormal wear of the ceramic bearing 8 and the impeller shaft 4 is caused. Will prevent. When the pumping operation is started, the lubricating water reduced so far is automatically replenished from the pumping water inlet 12.
[0009]
In the above embodiment, the impeller 15 is used as the liquid circulation mechanism, but a screw pump or the like may be used. Further, the pumping water inlet 12 may have a large diameter, and a strainer 16 may be provided on the pumping water inlet 12 to prevent foreign matter from entering the protective tube 10.
[0010]
【The invention's effect】
As is apparent from the above description, according to the present invention, the protective tube is used as the lubricating water reservoir without any special water reservoir, and the configuration is simple, and the volume of the reservoir is large. Moreover, since the ceramic bearings of all the pumps are in a water-immersed state, the ceramic bearings are not damaged even if the standby operation is started after a long period of time. In addition, even if evaporation, a small amount of leakage, etc. occur during the operation stop period, the amount of stored water is sufficient, so there is no risk of running out of lubricating water. Furthermore, since the circulating water is forced to circulate during the pump operation, foreign matters such as sand are prevented from accumulating on the ceramic bearing portion, and the bearing is less damaged.
Further, by providing a strainer at the pumping water inlet provided at the upper part of the protective tube, foreign matter can be prevented from entering, and damage to the ceramic bearing and the rotating body can be reduced.
[Brief description of the drawings]
FIG. 1 is a schematic view of a vertical shaft pump according to the present invention.
FIG. 2 is a partially enlarged view of FIG.
FIG. 3 is a cross-sectional view of a ceramic bearing.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Pumping pipe, 2 ... Bending part, 3 ... Vane casing, 4 ... Impeller shaft, 5 ... Impeller, 8 ... Ceramic bearing, 9 ... Shaft seal device, 10 ... Protection pipe, 12 ... Pumping water inlet, 13 ... Chamber, 14 ... circulation pipe, 15 ... liquid circulation mechanism, 16 ... strainer.

Claims (2)

In a vertical shaft pump that supports a lower end portion of an impeller shaft by a ceramic bearing provided in a vane casing, an impeller shaft extending above the vane casing is provided between the vane casing and a bent portion of a pumping pipe through which the impeller shaft passes. A chamber formed between the shaft seal device and the ceramic bearing, which is protected by a protective tube and provided with a pumping water inlet at the top of the protective tube, and a shaft seal device is provided below the ceramic bearing of the vane casing. And a lower portion of the pumped water inlet through a circulation pipe, and a liquid circulation mechanism is provided on the impeller shaft in the protective pipe. The vertical shaft pump according to claim 1, wherein a strainer is provided at the pumping water inlet.

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