JP4138213B2 - Standby operation pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a standby operation pump.
[0002]
[Prior art]
Buildings are densely populated in the city, and road pavement is also prevalent, so in heavy rain, rainwater flows into the drainage pump station without penetrating the ground. On the other hand, since the drainage pump of the drainage pump station driven by the engine requires time from the start to the completion of the start, if the drainage pump is started after the suction water level of the drainage pump station has risen, the drainage is not in time. For this reason, at the drainage pump station, the pump is started in the air at the same time as the precipitation, and a standby operation is performed to wait for the incoming water. Therefore, the pump will run idly in the atmosphere from when the pump is started until the water flows into the water absorption tank of the drainage pump station and the actual drainage is started.
[0003]
FIG. 4 is a schematic sectional view showing this type of conventional standby operation pump. As shown in the figure, this standby operation pump has an impeller casing 82 containing a discharge casing 81 and an impeller 87 and a suction bell mouth 84 attached to the lower part of the suspension casing 80, while the suspension pipe 80 is attached to the upper part of the suspension pipe 80. A curved discharge casing 85 is attached, and a shaft 86 installed inside these casings protrudes from the upper portion of the discharge casing 85 and is connected to driving means (not shown).
[0004]
Here, a guide vane 88 is fixed in the discharge casing 81, and a bearing casing 89 is attached to the center of the guide vane 88. A bearing (lower bearing) 91 of the shaft 86 is attached to a portion of the lower portion of the bearing casing 89 from which the shaft 86 projects. The bearing 91 is a water-lubricated bearing, and therefore, when idling, it slides dry and the temperature rises, and when rainwater flows in, it slides with water lubrication. A shaft sealing water portion 95 is provided at a portion of the shaft 86 that protrudes outward from the discharge casing 85 so as to prevent the pumped water from leaking out.
[0005]
The material of the bearing 91 is made of synthetic resin (for example, carbon fiber formed into a ring shape with synthetic resin). In the case of a normal water-lubricated bearing, ceramics are often used. However, in the case of ceramics, there is a risk of cracking due to intense heating when the dry operation is performed without water. For this reason, in the case of a standby operation pump, it is preferable to use a synthetic resin that can withstand both an idle operation and a water lubrication operation.
[0006]
However, the synthetic resin bearing 91 also has the following problems. FIG. 5 is an enlarged cross-sectional view of the main part showing the internal structure of the bearing casing 89. In the figure, during the pump drive, the head is higher in the upper part than in the lower part of the bearing casing 89. Therefore, in the bearing casing 89, due to this differential pressure, the gap a between the upper part of the bearing casing 89 and the shaft 86 is indicated by an arrow. As shown, a part of the water in the pumped water enters and a flow of water that flows downward from the bearing 91 is generated. The flow of water through the portion of the bearing 91 is necessary for the lubrication and cooling of the bearing. However, if the water to be pumped contains a slurry, a large amount of the slurry passes through the synthetic resin bearing 91, so that sliding wear occurs and its durability is hindered. There was a point. That is, the synthetic resin bearing 91 is convenient for idling, but is inconvenient for water lubrication with water containing a large amount of slurry.
[0007]
In order to prevent this inconvenience, as shown in FIG. 6, the protective tube 97 is extended so as to wrap the shaft 86 from the upper portion of the bearing casing 89 to the position of the shaft seal water portion 95, and water (fresh water) is supplied from the upper portion of the protective tube 97. It is also conceivable to supply and discharge from the portion of the bearing 91, thereby preventing the pumped water with slurry from entering the portion of the bearing 91.
[0008]
However, in this method, water supply equipment for supplying water and pipe connection work are required, and the installation is complicated.
[0009]
[Problems to be solved by the invention]
The present invention has been made in view of the above points, and its purpose is to prevent the bearing from being worn by slurry in the pumped water without providing a water supply facility or the like even if the bearing can be used for both dry and water lubrication. and to provide a standby operation pump which can be easily protected.
[0010]
[Means for Solving the Problems]
Standby operation pump according to the present invention for solving the above problems, installation an impeller installed in the casing of the bearing of the shaft for rotating the lower part of the bearing casing provided to surround the shaft in the impeller upward In the standby operation pump having the structure as described above, slurry inflow suppressing means for suppressing the intrusion of slurry into the bearing casing is provided at the upper portion of the bearing casing, and the slurry inflow suppressing means is provided so as to surround the periphery of the shaft. Slurry intruding into the bearing casing together with water from between the shaft and the bearing casing by installing the slurry inflow restraint seal from above and below and in contact with the outer peripheral surface of the shaft so that some water can flow. The structure is limited in quantity .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing an example of a pump using the first embodiment of the present invention. As shown in the figure, this pump has a discharge casing 15 and an impeller casing 20 containing an impeller 21 and a suction bell mouth 25 attached to the lower part of the suspension pipe 10 and is curved on the suspension pipe 10. The upper part of the shaft 11 installed with the discharge casings 30 installed and standing inside these casings protrudes outward from the curved upper side surface of the discharge casing 30 and is supported by an upper radial bearing and a thrust bearing (not shown). Thus, it is connected to driving means comprising a diesel engine, a gas turbine, etc. (not shown) via a speed reducer (not shown). A shaft seal water portion 70 is provided at a portion where the shaft 11 protrudes from the upper portion of the discharge casing 30 so that the pumped water does not leak outside. Reference numeral 75 denotes an intermediate bearing that supports the shaft 11 at an intermediate portion. The intermediate bearing 75 is provided at one or a plurality of locations as necessary.
[0013]
Here, on the upper portion of the impeller 21, a bearing casing 40 that is substantially cylindrical and formed in a shape that smoothes the flow of water is attached so as to cover the shaft 11, and the shaft 11 below the bearing casing 40 is attached. A bearing (underwater bearing) 43 that pivotally supports the shaft 11 in the radial direction is attached to a portion protruding from the shaft. The bearing casing 40 itself is fixed to the inner peripheral surface of the discharge casing 15 by guide vanes 45.
[0014]
FIG. 2 is an enlarged cross-sectional view of the main part showing the internal structure of the bearing casing 40. As shown in the figure, a cylindrical bearing 43 is installed in a portion of the lower surface of the bearing casing 40 through which the shaft 11 passes. In this embodiment, the bearing 43 is formed by forming a PEEK (polyetheretherketone) material into a cylindrical shape with carbon fibers built in, but other materials (for example, other synthetic resin materials, ceramics, etc.) You may comprise by structure. In short, any submersible bearing that can be used in both dry and water-lubricated states is acceptable.
[0015]
An underwater bearing sleeve 55 is fixed to the outer periphery of the shaft 11 side on which the bearing 43 slides, and the bearing 43 is fixed to the bearing casing 40 side via a protective ring 51 and a rubber elastic member 53.
[0016]
On the other hand, a slurry inflow suppression seal (slurry inflow suppression means) 60 is attached to a portion of the upper surface of the bearing casing 40 through which the shaft 11 passes. This slurry inflow suppression seal 60 is not a seal having a structure that completely seals between the bearing casing 40 and the shaft 11 but a seal that allows a certain amount of water to flow therethrough.
[0017]
If the shaft 11 is rotationally driven by driving the drive means (not shown) of the standby operation pump configured as described above, the water in the water absorption tank is sucked from the suction bell mouth 25 by the impeller 21 and is discharged into the discharge casing 30. The water is pumped up and drained to a predetermined place.
[0018]
At this time, since the upper head of the bearing casing 40 is higher than the lower head, a part of the water in the pumped water gradually passes from the portion of the slurry inflow suppression seal 60 into the bearing casing 40 as shown by the dotted line in FIG. Although intruding and flowing out from the bearing 43 portion, the amount of water and slurry to infiltrate is considerably smaller than in the case of the conventional example shown in FIG. The bearing 43 is not worn (or less).
[0019]
On the other hand, when a small amount of water flows in the bearing casing 40, heat generated from the bearing 43 can be easily released to the outside. In addition, air accumulation in the bearing casing 40 can be prevented.
[0020]
FIG. 3 is a schematic sectional view showing an example of a pump using a reference example of the present invention. In this reference example , the same parts as those in the embodiment shown in FIG. This pump is different from the pump shown in FIG. 1 in that, instead of attaching the slurry inflow suppressing seal 60, a cylindrical pumping water introduction pipe 65 is extended from the upper part of the bearing casing 40 so as to wrap the shaft 11, and the shaft sealing is performed. This is the point where the water part 70 is reached. Therefore, the upper end portion of the pumped water introduction pipe 65 is sealed by the shaft seal water portion 70. In other words, the shaft seal water portion 70 that seals the shaft 11 also serves as a seal for the pumped water introduction pipe 65. The shaft seal water portion 70 is not a seal that completely seals, but is composed of a shaft seal water portion having a structure through which a small amount of water passes.
[0021]
If the shaft 11 is rotationally driven by driving the drive means (not shown) of the standby operation pump configured as described above, the water in the water absorption tank is sucked from the suction bell mouth 25 by the impeller 21 and is discharged into the discharge casing 30. The water is pumped and drained to a predetermined place.
[0022]
At this time, since the water pressure of the pumped water is higher than the atmospheric pressure, a part of the pumped water enters the bearing casing 40 from the bearing 43 part, and further enters the pumped water introduction pipe 65 to enter the shaft seal water part 70. As a result, the entire interior of the bearing casing 40 and the pumped water introduction pipe 65 is filled with pumped water.
[0023]
As described above, since the seal of the shaft seal water portion 70 is not a seal that completely seals, the water filling the inside of the bearing casing 40 and the pumped water introduction pipe 65 gradually leaks from the shaft seal water portion 70 to the outside. New water gradually enters from the portion 43, so that the bearing 43 can be cooled and lubricated, and air can be prevented from accumulating. However, since the amount of water passing through the bearing 43 is small as in the first embodiment, the bearing 43 is not worn (or less) by the slurry entering with the water. That is, the wear amount of the bearing 43 can be reduced.
[0024]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible. Note that any shape, structure, or material not directly described in the specification and drawings is within the scope of the technical idea of the present invention as long as the effects and advantages of the present invention are exhibited.
[0025]
For example, in the above embodiment, only one bearing (radial bearing) 43 is installed in the bearing casing 40. However, depending on the configuration of the pump, other bearings (radial bearing and / or thrust bearing) may be provided in the bearing casing 40 in addition to the bearing 43. ) May be installed. Needless to say, various modifications can be made to the shape and structure of the pump.
[0026]
【The invention's effect】
As described above in detail, according to the present invention, even a bearing that can be used for both dry and water lubrication can be easily protected from abrasion due to slurry in the pumped water without providing water supply facilities. It has the excellent effect that it can be done (the amount of wear can be reduced).
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing an example of a pump using a first embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of a main part showing an internal structure of a bearing casing 40. FIG.
FIG. 3 is a schematic cross-sectional view showing an example of a pump using a reference example of the present invention.
FIG. 4 is a schematic sectional view showing a conventional standby operation pump.
5 is an enlarged cross-sectional view of a main part showing an internal structure of a bearing casing 89. FIG.
FIG. 6 is a schematic sectional view showing another standby operation pump.
[Explanation of symbols]
10 Suspension pipe 11 Shaft 15 Discharge casing 20 Impeller casing 21 Impeller 25 Suction bell mouth 30 Discharge casing 40 Bearing casing 43 Bearing 45 Guide vane 51 Protective ring 53 Elastic member 55 Underwater bearing sleeve 60 Slurry inflow suppression seal (Slurry inflow suppression seal) means)
65 Pumped water introduction pipe 70 Shaft seal water section

Claims (1)

In a standby operation pump having a structure in which a shaft bearing for rotationally driving an impeller installed in a casing is installed at a lower portion of a bearing casing provided so as to surround the shaft above the impeller,
A slurry inflow suppressing means is provided at the top of the bearing casing to prevent slurry from entering the bearing casing.
The slurry inflow suppression means is installed by sandwiching a slurry inflow suppression seal provided so as to surround the periphery of the shaft from above and below and in contact with the outer peripheral surface of the shaft to such an extent that some water can circulate. A standby operation pump characterized in that it has a structure that limits the amount of slurry flowing into the bearing casing together with water from between the casings.

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