The structural type of stainless steel submersible electric pump is a unit that tightly integrates the pump and motor into a whole and works together in the submersible. Generally, stainless steel submersible electric pumps can be divided into two main structural forms: upper pump and lower pump, based on the relative position of the pump and motor. The submersible pump structure has the pump on top and the motor below. This structure is beneficial for reducing the radial size of the pump, so it is mostly used for submersible pumps and small submersible pumps in wells. In the structure of submersible pumps, wet submersible motors are usually used.
The inner cavity of the stainless steel submersible pump motor is filled with clean water, transformer oil or spindle oil, and its stator coil is wound with oil resistant and water-resistant enameled wire to strengthen insulation. The rotor runs immersed in liquid, and the outside of the motor is submerged in water, with good cooling conditions. Wet motor bearings can be made of engineering plastic bearings or rolling bearings. The shaft extension end and bearing are sealed with skeleton oil seals or mechanical seals. The stainless steel submersible pump seal only serves to prevent sludge and dirty water, and its structure is simple. Wet submersible pumps have solved the sealing problems of electromagnetic and bearing parts, and have been widely promoted and applied earlier. However, the water friction loss between the stator and rotor of wet motors is relatively large, which is proportional to the fifth power of the rotor outer diameter.
Therefore, it is usually slender to reduce friction losses and improve motor efficiency.
The stainless steel submersible pump located below the motor is called a submersible pump under the pump, which is divided into two types: internal and external.
The liquid conveyed by the submersible pump with built-in pump first passes through the annular channel surrounding the motor, cools the motor, and then flows out from the pump pressure outlet. This type of pump does not have to worry about the temperature rise of the motor even when it is close to the suction tank, so its application range is increasingly expanding. The external submersible pump directly discharges the liquid from the pressure chamber or guide vane outlet behind the impeller, and the motor is cooled by the pumped liquid. Due to the fact that the stainless steel submersible pump structure can work in shallow liquids, it is often used as the main structural form of submersible pumps, especially large-diameter submersible pumps, in working faces.
