JP2588987Y2 - Dry type submersible motor 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 dry submersible motor pump employing an electric motor as a rotary drive source for an impeller.

[0002]

2. Description of the Related Art Submersible motor pumps employing an electric motor as a rotary drive source for an impeller can be broadly classified into three types: a water seal type, an oil seal type, and a dry type. In these submersible motor pumps, the water-sealed type pump is filled with water around the motor coil and the rotor of the electric motor, and the oil-sealed type pump is filled with oil around the motor coil and the rotor. An air layer or space is formed around the coil and the rotor, and has essentially the same structure as a land motor.
For this reason, the heat generated by the rotor of the electric motor, which is a heat source, is such that water or oil is in contact with the rotor portion and is radiated to the outside with good heat transfer in a water seal type or an oil seal type. Since the air layer is around the rotor and the rotor, it can be said that the heat insulation function of the air layer makes it easy to store heat inside the motor.
Particularly in a high-power motor, not only does the rotor temperature tend to be too high, but also the rotating shaft of the motor has a large shaft diameter, so the amount of heat stored inside the rotating shaft increases accordingly. The tendency for the temperature to rise too high is further promoted.

[0003]

[Problems to be solved by the invention] As described above, conventionally,
The dry-type submersible motor pump has a problem that the rotor temperature and the rotating shaft temperature of the electric motor may be excessively increased. In particular, such a tendency is remarkable in a dry-type submersible motor pump using a high-output electric motor.

[0004] In view of this, the inventor of the present application has designed a dry-type submersible motor pump with the intention of effectively radiating heat generated in the rotor of the electric motor to the outside to suppress a rise in the rotor temperature and heat storage in the rotating shaft. As a result of intensive research, the present inventors have found out that the required strength of the rotating shaft can be satisfied even if the rotating shaft is hollow, and used this fact to complete the present invention.

That is, in the present invention, a hollow shaft is used as a rotating shaft, and the air in the internal space of the housing in which the electric motor is installed is allowed to flow naturally or forcibly through the internal passage of the hollow shaft. An object of the present invention is to provide a dry-type submersible motor pump capable of suppressing heat generation in a rotor and heat storage in a rotating shaft by having a function as a heat medium or a cooling medium.

[0006]

According to the dry submersible motor pump of the present invention, an electric motor is installed in a space surrounded by a housing provided in a pumping passage, and an impeller is connected to a rotating shaft of the electric motor. In a dry-type submersible motor pump in which water sucked by the rotation of the impeller is discharged through the pumping passage, the rotating shaft is a hollow shaft, and internal passages of the hollow shaft are provided on both sides of the electric motor. The housing is open at a position facing the internal space of the housing, and a return passage communicating with the internal space on both sides sandwiching the electric motor is formed in the housing.

[0007]

In this configuration, when the electric motor is operated, the water sucked by the rotation of the impeller rises in the pumping passage. On the other hand, the rotary shaft of the electric motor, that is, the hollow shaft, is open at a position where the internal passage faces the internal space of the housing provided on both sides of the electric motor. A ventilation action is performed in which air in the space flows through the internal passage of the hollow shaft. Heat generated by the motor (heat generated by the rotor)
And the hollow shaft, that is, the rotating shaft is cooled. Further, the air convected in the internal passage of the hollow shaft by the ventilation action is cooled by the water flowing through the pumping passage when passing through the return passage of the housing after passing out of the internal space of the housing.

[0008]

1 is a sectional view showing a main part of a dry type submersible motor pump according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a column, and an internal space of the column 1 is a pumping channel 2.

Reference numeral 3 denotes a pump main body. In this embodiment, the pump main body 3 includes a housing 4 assembled in a substantially vertical cylindrical shape, and an electric motor 6 installed in a part of a space 5 surrounded by the housing 4. And an impeller 8 connected to the rotating shaft 7 of the electric motor 6. The electric motor 6 has the rotating shaft 7, a rotor 9 to which the rotating shaft 7 is fixed, and a coil 10 as a stator provided around the rotor 9, which are surrounded by a cylindrical frame 11. Have been.

The housing 4 includes a frame 11, a cylindrical lid 13 connected to an upper end of the frame 11 via an upper partition 12, and an upper lid 14 closing an upper end opening of the lid 13. And a pump casing 16 connected to a lower end of the frame 11 via a lower partition wall 15. Then, the suction casing 1 is inserted into the pump casing 16.
8 and the pump casing 16
Is provided with a guide vane 17. The impeller 8 is provided on a boss 19, and the boss 19 is
0 is attached. The rotating shaft 7 is rotatably supported by a bearing 21 provided on the upper partition 12 and a bearing 22 provided on the lower partition 15. Also,
The rotating shaft 7 is also supported by a mechanical seal 23 provided on the pump casing 16. 5a, 5b,
5c is a space secured above and below the electric motor 6 inside the frame 11 and the lid 13 and 14a is a cable insertion port.

The housing 4 of the pump body 3 is provided in the water pumping passage 2 inside the column 1, and in this state, the pump casing 1 extends from the lower end of the column 1.
6 and the suction casing 18 are projected.

Next, a hollow shaft is used as the rotary shaft 7 as shown in the drawing, and an internal passage 7a is opened at the upper end of the hollow shaft at a position facing the space 5c inside the cover fitting 13. 7b. Further, the internal passage 7a has an opening 7c in the peripheral surface thereof in the middle part of the hollow shaft, that is, the rotating shaft 7, and this opening 7c faces the space 5b inside the frame 11 secured below the electric motor 6. I have. On the other hand, the frame 11 constituting the housing 4 is formed with a return passage 24 which communicates the spaces 5a, 5b on both sides of the electric motor 6.

Here, the rotating shaft 7 composed of a hollow shaft is mounted on the bearing 2.
Even if it is an integral shaft in which the entire length from the upper end supported by 1 to the lower end connected to the boss 19 is integrally formed, a halfway point in the axial direction is a split shaft connected by spline coupling or the like. There may be.

In the dry-type submersible motor pump described above, when the electric motor 6 is driven, the rotating shaft 7 rotates with the rotor 9 and the impeller 8 rotates with the rotating shaft 7. For this reason, after the water sucked from the suction casing 18 is rectified by the guide vanes 17 of the pump casing 16,
The water flows upward through the water pumping channel 2 and is discharged from a discharge port (not shown).

During the operation of the pump, the air in the space 5c inside the cover fitting 13 and the space 5b inside the frame 11 secured below the electric motor 6 is supplied to the rotary shaft 7, that is, the internal passage 7a of the hollow shaft. At the same time, the air in the upper space 5a and the lower space 5b of the electric motor 6 circulates in the return passage 24, and the air flows in the lower space 5b of the electric motor 6, the hollow internal passage 7a, and the upper lid 13. Convection flows through the internal space 5c, the space 5a above the electric motor 6, and the return passage 24. Therefore, heat generated by the electric motor (heat generated by the rotor) and the hollow shaft, that is, the rotating shaft, are cooled by the ventilation effect when air convections through the internal passage 7a of the hollow shaft. Further, the air that has convected through the internal passage 7a of the hollow shaft by the ventilation action is cooled by the water flowing through the water pumping passage 2 when passing through the return passage 24, and is then subjected to the ventilation action again.

Here, as shown in FIG. 2, a curved passage 25a of an L-shaped short pipe 25 is communicated with an opening 7c of an internal passage 7a of a rotary shaft 7, that is, a hollow shaft, and an opening of the curved passage 25a. If the rotation shaft 25 rotates in the rotation direction R of the rotation shaft 7, the rotation of the rotation shaft 7
The air is forcibly taken into the internal passage 7a from the internal passage 7a through the curved passage 25a, so that the solid arrow a shown in FIGS.
As described above, forced air is blown by convection of air, and a more efficient cooling action is exhibited. In FIG. 1, the flow of water flowing through the water pumping channel 2 is indicated by a white arrow b.

The amount of heat removed from the rotor 9 and the cooling effect of the rotary shaft 7 vary depending on the amount of air (air flow) convection through the internal passage 7a of the rotary shaft 7, that is, the hollow shaft, and the air flow forms the internal passage 7a. It depends on the diameter of the hole. From this, it is possible to set the ventilation amount that can perform effective cooling by appropriately determining the diameter (hole diameter) of the hole forming the internal passage 7a.

[0018]

According to the present invention, the heat generated by the motor (heat generated by the rotor) constitutes the rotating shaft even in a dry-type submersible motor pump in which the air around the coils and the rotor of the motor is an air layer. The hollow shaft is taken away by the convection of the air passing through the internal passage, and at the same time, the rotating shaft is cooled by the ventilation, and the air exiting the internal passage is cooled by the water flowing through the pumping passage while passing through the return passage. After that, it will again convect the internal passage,
This prevents the rotor temperature of the electric motor from rising too high and prevents the heat from being stored in the rotating shaft, which not only helps to improve the safety of the pump during operation, but also uses a rotating shaft with a large shaft diameter. There is an effect that it is possible to manufacture a dry type submersible motor pump having a large output motor.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of a dry-type submersible motor pump according to an embodiment of the present invention.

FIG. 2 is a horizontal cross-sectional view of a main part of a case in which forced ventilation is enabled in the dry type submersible motor pump according to the embodiment of the present invention.

[Explanation of symbols]

 2 Pumping path 4 Housing 5a, 5b, 5c Space on both sides sandwiching motor 6 Motor 7 Rotating shaft 7a Internal passage of hollow shaft 7b, 7c Opening of internal passage 8 Impeller 24 Return passage

──────────────────────────────────────────────────続 き Continued on the front page (56) References JP-B-36-20928 (JP, B1) (58) Fields investigated (Int. Cl. ⁶ , DB name) F04D 13/08 F04D 29/04 F04D 29 / 58

Claims (1)

(57) [Scope of request for utility model registration] An electric motor is installed in a space surrounded by a housing provided in a pumping passage, an impeller is connected to a rotating shaft of the electric motor, and the water sucked by the rotation of the impeller is pumped by the pump. In the dry type submersible motor pump discharged through a passage, the rotary shaft is a hollow shaft, and the internal passage of the hollow shaft opens at a position facing the internal space of the housing provided on both sides sandwiching the electric motor. And a return passage communicating with the internal space on both sides of the electric motor in the housing.