JP3623099B2 - underwater pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a submersible pump, and more particularly, to a submersible pump suitable for pumping up sewage installed in a manhole or a sewage relay pump station.
[0002]
[Prior art]
As shown in FIG. 2, this type of submersible pump generally includes a pump casing 1, a prime mover 2, an impeller 3, a mechanical seal 4, and an elastic seal ring 5.
[0003]
The pump casing 1 has a suction port 6 facing downward at the bottom, a suction bell mouth 7 is attached to the suction port 6, and the upper part is closed by a casing cover 8. 6 and a suction bell mouth 7 are formed, and a spiral chamber 9 having a vertical axis is formed, and a discharge passage 10 communicating with the spiral chamber 9 is formed at a side portion. The discharge passage 10 communicates with the pumped water pipe 17 through the discharge bent pipe 11.
[0004]
The prime mover 2 is a submersible motor and is liquid-tightly mounted on a prime mover frame 12 that is placed and connected to the casing cover 8. Further, the output shaft 13 of the prime mover 2 extends through the through hole 14 provided in the casing cover 8 in the vertical direction and extends into the pump casing 1, and the impeller 3 fixed to the tip end of the output shaft 13 is connected to the pump casing 1. It is housed in a rotatable manner.
[0005]
A mechanical seal accommodating portion 15 is provided between the casing cover 8 and the prime mover frame 12, and the mechanical seal 4 surrounding the output shaft 13 is accommodated in the mechanical seal accommodating portion 15, and the mechanical seal 4 moves into the prime mover frame 12. Prevents water intrusion.
[0006]
On the other hand, an elastic seal ring 5 formed of an elastic material such as rubber is interposed in an annular space 16 between the inner periphery of the vertical through hole 14 provided in the casing cover 8 and the outer periphery of the boss portion 3A of the impeller 3. The sealing action of the elastic seal ring 5 prevents the solid matter mixed in the sewage and entering the pump casing 1 from entering the mechanical seal housing portion 15 to protect the mechanical seal 4.
[0007]
In this type of submersible pump, the pump stop water level LWL is set to a low position corresponding to the lower end of the suction bell mouth 7 in order to prevent accumulation of scum generated in a manhole or a sewage relay pump station. The operation is often continued until the suction water tank 18 is almost empty. However, by adopting an operation method in which the pump stop water level LWL is set at such a low position, air enters the pump casing 1 through the suction bell mouth 7 and the suction port 6 when the pump is stopped. Even if the water level rises to the operation start water level HWL, a part of the air that has entered enters an air-lock state in which air remains in the impeller housing portion above the spiral chamber 9 in the pump casing 1, and enters the pump casing 1. The inflow of water is hindered, and an idle operation in which water cannot be pumped at the time of restart at the operation start water level HWL is generated. For this reason, in the conventional submersible pump, an air vent hole 19 is provided in the pump casing 1 or the casing cover 8, and air is discharged from the air vent hole 19 so that pumping is not possible when restarting at the operation start water level HWL. Devised to avoid driving.
[0008]
However, in the configuration in which air is discharged from the air vent hole 19 provided in the pump casing 1 or the casing cover 12, the air vent hole 19 is blocked by solid matter mixed into the sewage and entering the pump casing 1. There is a possibility of causing an idle operation that is lost and cannot be pumped at the time of restart at the operation start water level HWL.
[0009]
The occurrence of such inconvenience can be solved by causing a part of the lower end side of the impeller 3 to protrude into the spiral chamber 9 as shown in FIG. That is, even if the water level rises to the operation start water level HWL in FIG. 2 and air remains in the impeller housing portion above the spiral chamber 9 in the pump casing 1, the blades are added to the water existing in the spiral chamber 9. Since a part of the lower end side of the car 3 is immersed, water can be pumped. However, in such a configuration, the passing particle diameter D1 of the spiral chamber 9 is smaller than the diameter D of the suction port 6 and the discharge passage 10, and the solid matter passing through the suction port 6 is between the impeller 3 and the pump casing 1. It ’s boring.
[0010]
[Problems to be solved by the invention]
That is, in the conventional submersible pump, if the air vent hole is blocked by solid matter mixed into the sewage and entering the pump casing, the function of discharging the air that has entered the pump casing is lost, and pumping is not performed when the pump is restarted. There is a risk of causing an impossible idling. Further, in the submersible pump configured to eliminate such inconvenience, the passing particle diameter of the spiral chamber is smaller than the diameter of the suction port and the discharge passage, and the solid matter passing through the suction port is separated from the impeller. It will be pinched between pump casings.
Therefore, the present invention can start pumping even if the air vent hole is blocked by solid matter that has entered the pump casing, and ensures a large passage particle size comparable to the diameter of the suction port and the discharge passage, It aims to provide a submersible pump that can be operated.
[0011]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the submersible pump according to the present invention has a suction port opened downward at the bottom, the top is closed by a casing cover, and the interior communicates with the suction port in the vertical direction. A pump casing in which a spiral chamber having an axis is formed and a discharge passage communicating with the spiral chamber is formed in a side portion; a prime mover that is liquid-tightly installed in a prime mover frame connected to the casing cover; It includes an output shaft of the engine extending in the pump casing through the vertical through hole provided on the casing cover, and an impeller rotatably accommodated this is fixed to the output shaft in the pump casing and in water pump is, as the gradient decreases towards the lower end of the impeller to the output shaft, causes the臨出a portion of lower end side in the swirl chamber, the swirl It is characterized in that the bottom from the outer peripheral side is formed by the inclined surface inclined slope downward toward the suction port.
[0012]
According to the present invention, the lower end of the impeller is inclined downward toward the output shaft so that a portion of the lower end side protrudes into the spiral chamber and the bottom surface of the spiral chamber is directed from the outer peripheral side toward the suction port. By forming the inclined surface inclined downward, the passing particle diameter of the spiral chamber can be enlarged.
Further, in the present invention, the passage particle diameter of the flow path formed by the lower end of the impeller and the bottom surface of the spiral chamber is expanded to the diameter of the suction port, so that the solid matter passing through the suction port is discharged. It is possible to pass to the exit.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an enlarged sectional view showing a main part of one embodiment of the present invention. The overall structure of the submersible pump to which the present invention is applied is not different from the conventional example described in FIG. 2 and FIG. explain. In FIG. 1, the lower end of the impeller 3 is inclined downward toward the output shaft 13 so that a part of the lower end side protrudes into the spiral chamber 9, and the bottom surface of the spiral chamber 9 extends from the outer peripheral side to the upper end of the suction port 6. It is formed by the inclined surface 9A inclined downward.
[0014]
With such a configuration, even if the water level rises to the operation start water level HWL in FIG. 2 and air remains in the impeller housing portion above the spiral chamber 9 in the pump casing 1, the lower end of the impeller 3 is moved. Since a part of the lower end side is projected to the spiral chamber 9 as a downward slope toward the output shaft 13, a part of the lower end side of the impeller 3 is immersed in the water present in the spiral chamber 9. It will be. For this reason, water can be pumped by rotating the impeller 3. In addition, since the bottom surface of the spiral chamber 9 is formed by the inclined surface 9A inclined downward from the outer peripheral side toward the upper end of the suction port 6, the passage particle diameter D1 of the spiral chamber 9 is set to the suction port 6 and the discharge passage. It is possible to expand up to 100% of 10 apertures D. For this reason, it becomes possible to let the solid substance which passed the suction inlet 6 pass to the discharge outlet 10. FIG.
[0015]
【The invention's effect】
As described above, according to the present invention, the lower end of the impeller is inclined downward toward the output shaft so that a part of the lower end side protrudes into the spiral chamber and the bottom surface of the spiral chamber is sucked from the outer peripheral side. Since it is formed by the inclined surface inclined downward toward the mouth, the passing particle diameter of the spiral chamber can be expanded to 100% of the diameter of the suction port and the discharge passage. Thereby, it becomes possible to let the solid substance which passed the suction inlet pass to a discharge outlet.
[Brief description of the drawings]
FIG. 1 is an enlarged sectional view showing a main part of an embodiment of the present invention.
FIG. 2 is an overall configuration diagram showing an example of a conventional submersible pump.
FIG. 3 is a partial configuration diagram showing another example of a conventional submersible pump.
[Explanation of symbols]
Reference Signs List 1 pump casing 2 prime mover 3 impeller 5 elastic seal ring 6 suction port 8 casing cover 9 spiral chamber 9A inclined surface 10 discharge passage 12 prime mover frame 13 output shaft

Claims (2)

A downward suction port is opened at the bottom, the top is closed by a casing cover, a spiral chamber having an axis in the vertical direction is formed in the interior, and the spiral chamber is formed on the side. A pump casing formed with a discharge passage communicating with the casing, a prime mover that is liquid-tightly installed in a prime mover frame connected to the casing cover, and a pump casing that passes through a vertical through hole provided in the casing cover. an output shaft of the prime mover extending within, the submersible pump that includes an impeller which is rotatably housed the fixed to the output shaft in the pump casing, the output shaft of the lower end of the impeller as the slope down toward the inclined part of the lower side together to臨出the swirl chamber, the gradient decreases towards the inlet to the bottom of the swirl chamber from the outer peripheral side Water pump, characterized in that formed by the inclined surfaces that. The submersible pump according to claim 1, wherein a passage particle diameter of a flow path formed by a lower end of the impeller and a bottom surface of the spiral chamber is expanded to a diameter of a suction port.

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