Introduction To Several Maintenance Methods For Submersible Pumps

There are several types of submersible pumps. The wire insulation in the motor can be oil-cooled, water-cooled or dry-type. Before using a submersible pump, it is necessary to read the manual first. Do not make any mistakes. If it is not used for a long time, the impeller must be turned before use. Otherwise, it may get stuck due to long-term inactivity and burn out the insulation. Before starting the pump, the suction pipe and the pump must be filled with liquid. After starting the pump, the impeller rotates at high speed. The liquid in it rotates together with the blades. Under the action of centrifugal force, it flies away from the impeller and is ejected outward. The ejected liquid gradually slows down in the diffusion chamber of the pump casing and gradually increases in pressure. Then it flows out from the pump outlet and the discharge pipe. At this time, due to the liquid being thrown to the surrounding area, a vacuum low-pressure area without air or liquid is formed at the center of the impeller. The liquid in the liquid pool flows into the pump through the suction pipe under the action of atmospheric pressure. The liquid is continuously sucked up from the liquid pool and continuously flows out through the discharge pipe. In China's irrigation areas, another type of pump that is widely used is the submersible electric pump. The submersible electric pump integrates the motor and the pump into one unit and works underwater at a depth below the water surface. Types of submersible electric pumps: 1. According to the usage occasion, the types of submersible electric pumps can be classified as: (1) Surface operation submersible electric pump. It is used to lift water from shallow wells, ditches, ponds, rivers, and lakes. It is convenient to move. The pump part is mostly a vertical single-stage pump. (2) Deep well submersible pump. It is used to lift water from deep wells. The lifting height is large. The pump part is generally a vertical multi-stage pump. 2. According to the waterproofing methods of the motors, the types of submersible pumps are classified as follows: (1) Dry submersible pumps. At the shaft extension end of the motor, mechanical seals or air cushion seals are used to achieve a tight seal to prevent water from entering the motor cavity and maintaining the interior dry. However, due to the limitations of the sealing structure, the depth of submersion underwater cannot be too large, such as stainless steel submersible pumps. (2) Semi-dry submersible pumps. The stator and rotor of the motor are separated by a shielding cover, so that the stator is sealed and isolated from water, while the rotor operates in water. Due to the existence of the shielding cover, the air gap increases, affecting the motor's efficiency. Currently, it is rarely used. (3) Oil-filled submersible pumps. The motor cavity is filled with insulating oil to prevent water and moisture from invading the motor windings and to provide insulation, cooling, and lubrication functions. The insulating oil of the motor can be pressurized. To prevent oil leakage and water infiltration, a sealing device is still required at the shaft extension end. When the sealing fails, it will cause water pollution, so it is not suitable for extracting domestic water. In addition, the rotor of the motor rotates in oil, resulting in high resistance and low motor efficiency. (4) Wet submersible pumps. The stator winding of the motor uses waterproof insulated wires. The motor is filled with pure water, and the rotor operates in water, providing better heat dissipation performance. This type of pump has higher requirements for materials and stricter requirements for the rust prevention of components. In recent years, the number of submersible pumps used in rural areas has increased. To reduce accidents during use, it is necessary to strengthen regular maintenance and upkeep. 1. Regularly inspect the sealing components. For the various sealing components of the submersible pump, such as oiling screws, rubber sealing rings, and oil-filled electric pump's sealing box, a check should be conducted before each use. Loose ones should be tightened promptly, and those with loose seals should be replaced immediately to ensure safety. 2. Replace the engine oil every 500 hours after oil-immersed electric pumps are used. The engine chamber's engine oil should be replaced once a year. The replaced oil should be clean No. 5 or No. 10 engine oil. For wet electric pumps, lithium-based lubricating grease should be replaced once every 2,000 hours of operation. 3. Prevent rusting. When the submersible pump is not in use, it should be wiped clean and placed in a ventilated and dry place. If the surface of the electric pump is damaged and has lost its paint, the rust should be removed promptly, and anti-rust paint should be applied for protection. 4. Conduct comprehensive maintenance of the submersible pump. Generally, a comprehensive maintenance should be carried out once every two years. For worn components and those with poor sealing performance, they can be repaired if possible, and all components that cannot be repaired should be replaced. It is not advisable to use them勉强, as this may cause serious consequences.