External installation type submersible electric pup :
1.Typical structure of external electric submersible pump
The upper part of the submersible electric pump is a vertical cage type asynchronous motor, and the stator structure, the rotor structure and the end cover structure are similar to the common vertical induction motor. In the stator and end cover, the mouth of the mating surface with O shaped rubber sealing ring, cable from the upper cover eduction sealed with a rubber washer is pressed down, the submersible motor shaft extension end is provided with a single mechanical seal or mechanical seal. The shaft of the pump type submersible pump is extended, and a rubber oil seal is arranged on the outer side of the mechanical seal. When the submersible pump submerged operation, the composite sealing structure can effectively prevent internal and external sewage or solid impurities into the motor, so as to ensure the normal working condition of stator winding and bearings and other parts of the electric submersible pump. The lower part of the submersible pump for the pump, comprising a pump body, impeller, pump cover, strainer and pipe joints and other parts. The upper end cover of the submersible electric pump is provided with a heat protector, and the heat element is close to the upper end of the stator winding of the submersible electric pump, and the current element is connected in series with the stator winding. When the phase interruption due to various causes of overload or power submersible pump operation, thermal protector can automatically cut off the power connection of the stator winding, the submersible pump to immediately stop operation, protection of electric submersible pump is not caused by overload or power off phase fault and damage.
2.External installation of submersible electric pump cooling
External mounted electric submersible pump is running, the water from the water flows into the impeller, the pump flow through to the pipe joint, and then from the water outlet pipe. In the whole process of drainage submersible pump pumping water did not go through the motor base surface. That is to say, the structure of the external installation type submersible electric pump can not be used for cooling water discharged from the water, and can only use the water in the surrounding environment of the submersible pump to carry out cooling. That is to say, the structure cannot exterior type submersible pump using its discharged water for cooling, cooling can only use the submersible pump in the surrounding environment of water But when the submersible pump drainage process, the upper part of the motor casing above the water, the motor is in the air cooling condition, heat dissipation conditions greatly deteriorated. In order to improve the dry cooling conditions external type submersible pump, submersible pump power is often larger frame made of jacket type, will be part of the liquid pump outlet into the frame clip cooling motor set. When the electric submersible pump is used for a large area, the motor casing is often exposed to water, and the cooling effect of the dry type submersible electric pump adopting the jacket type structure is better. Because of this jacket type dry type submersible electric pump seat clamp sleeve type in small cooling water, its cooling effect is slightly worse than the dry type built-in type submersible pump.
