JP2000303987A - Dry pit type submerged electrically driven pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dry pit type submerged electrically driven pump capable of being so constituted as to be simple in structure, excellent in maintenability at low cost, and of being prevented from being degraded in pump efficiency. SOLUTION: A first water camber 10 is interposed between a spiral chamber 2 and an oil chamber 8, a second water chamber 11 is provided around the outer circumference of the oil chamber 8, the first water chamber 10 is communicated with the spiral chamber 2 by way of the small gap(g) of the inner circumferential surface of a liner ring 7, the first water chamber 10 is connected with the second water chamber 11 through a water channel 12, an air vent valve 13 is fitted to the upper end part of the second water chamber 11, and heat radiating fins 15 are stretched so as to be provided over the outer circumference of a motor frame 14 erected upward over an oil chamber 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for an out-of-tank submersible electric pump.

[0002]

2. Description of the Related Art It is well known that a radiating fin for air cooling is stretched around the outer periphery of a motor frame of a motor used in the air. However, in order to cool the heat generated during operation of the submersible electric pump at a low water level by the radiating fins, the effect cannot be produced unless an extremely large radiating surface area is secured. At present, the motor part of the submersible electric pump made on the assumption that it is immersed in water is not provided with radiating fins, and there is an oil chamber etc. between the spiral chamber and the motor part. Presence blocks heat conduction. Therefore, when the motor is used in an extremely low water level exposed to the air, the motor cooling action during operation is extremely reduced, and the motor protection device is frequently started and stopped by the operation of the motor protection device. In this case, a motor burnout accident may be caused.

As a measure to prevent the motor cooling action at the time of a low water level from being lowered, as shown in FIG.
4 is surrounded by an outer cover C, and an annularly surrounded water chamber 111 is communicated with the inside of the vortex chamber 102 of the pump,
In addition, there is one in which the upper part of the water chamber 111 is communicated with the pump suction port 103 by a circulation pipe P so as to absorb the heat generated by the motor by circulation circulation when the pump is driven. However, adopting such a large-scale and complicated structure has disadvantages in that the entire pump is increased in size, the manufacturing cost is increased, the maintainability is poor, and the pump efficiency is reduced due to circulation circulation.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cooling device for an out-of-tank type submersible electric pump which has a simple structure and a compact structure, is low in cost, has excellent maintainability, and does not lower the pump efficiency at all. It is in.

[0005]

In the cooling device for an out-of-tank type underwater electric pump according to the present invention, a first water chamber is provided between a volute chamber and an oil chamber, and a second water chamber is provided on the outer periphery of the oil chamber. The first water chamber is connected to the spiral chamber through a narrow gap in the inner peripheral surface of the liner ring, the first water chamber and the second water chamber are connected by a water passage, and the second water chamber is connected to the first water chamber. An air vent valve was attached to the upper end of the chamber, and radiation fins were provided on the outer periphery of the motor frame that was set up above the oil chamber.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments will be described below with reference to the drawings.

Reference numeral 1 denotes a pump casing, the inside of which is formed in a swirl chamber 2, which opens a suction port 3 on the lower surface and leads a discharge port 4 to one side. Reference numeral 5 denotes an impeller housed in the spiral chamber 2 mounted on the lower portion of the motor shaft 6. Reference numeral 7 denotes a liner ring fitted to the boss portion of the impeller 5, and an inner peripheral surface thereof and the boss. A gap g is formed between the outer peripheral surface and the outer peripheral surface. Reference numeral 8 denotes an oil chamber containing a lubricating oil of a shaft sealing device 9;
Reference numeral 0 denotes a first water chamber provided between the spiral chamber 2 and the oil chamber 8 and is in communication with the spiral chamber 2 through a gap g on the inner peripheral surface of the liner ring 7. A second water chamber 11 is provided around the outer periphery of the oil chamber 8 and communicates with the first water chamber 10 through a water passage 12. 13 is an air vent valve provided at the upper end of the second water chamber 11, and 14 is an oil chamber 8
Motor frame erected on the upper part of the motor, 15 ... 1
Reference numeral 5 denotes a radiation fin stretched around the outer periphery of the motor frame 14. A main part of each of the above members is made of a heat conductive material such as a metal.

[0008]

When the pump starts operating at a low water level at which the motor is exposed to the air, a part of the pumped water is removed by the action of the water pressure generated in the volute chamber 2 through the gap g on the inner peripheral surface of the liner ring 7. To flow into the first water chamber 10 and further into the water passage 12
To the second water chamber 11, and the air in the water chamber 11 is exhausted from the air bleed valve 13 to be full, so that the water level on the outer periphery of the pump (minimum operating water level LWL) The water cooling action by the pumping water filled in the water chamber 11 at a higher water level and the air cooling action by the radiation fins 15 on the outer periphery of the motor frame 14 are combined to perform effective pump cooling. When the pump stops and the water pressure in the volute 2 decreases, the air is sucked from the air release valve 13 and the pumped water that has absorbed the motor heat and has been heated falls down in the second water chamber 11 to reach the water level on the outer periphery of the pump. (Minimum operating water level L.
W. At the same level as in L), when the operation of the pump is started again, new pumped water is filled in the second water chamber 11 and used for absorbing motor heat. In this way, the pump is automatically replaced with a new pump every time the pump is started and stopped, so that the cooling effect is maintained without change from time to time.

[0009]

According to the cooling device for an out-of-tank type submersible electric pump according to the present invention, the cooling system using both the air-cooling type and the water-cooling type pumps the heat generated by the motor which cannot be completely cooled by the air-cooling action of the radiation fins. Since it is configured to complement with the use of water cooling, the radiating fins need only have a small surface area and the volume of the annular water chamber is small, so it can be constructed compactly and compactly, it can be manufactured at low cost, and it is easy to maintain And that the pump efficiency is not reduced.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of a main part of a submersible electric submersible pump provided with a cooling device of the present invention.

FIG. 2 is a vertical sectional side view of a main part of an external submersible electric pump provided with a conventional cooling device.

[Description of Signs] 2 Pump vortex chamber 7 Liner ring g Liner ring inner circumferential gap 8 Oil chamber 10 First water chamber 11 Second water chamber 12 Water passage 13 Air release valve 14 Motor frame 15 Radiation fin

Claims (1)

[Claims] 1. A first water chamber is provided between a spiral chamber and an oil chamber, a second water chamber is provided around an outer periphery of the oil chamber, and the first water chamber is provided on an inner peripheral surface of a liner ring. The first water chamber and the second water chamber are connected to each other by a water passage through the narrow chamber, and an air vent valve is provided at an upper end of the second water chamber.
A cooling device for an out-of-tank type submersible electric pump, characterized in that radiation fins are stretched around an outer periphery of a motor frame provided upright above an oil chamber.