Multistage Centrifugal Pump Electric Water Pump

The multi-stage pump is designed and optimized by computer, and the production company possesses technical strength, rich production experience and perfect testing methods, thus ensuring the stable and reliable quality of the product. Multi-stage pumps, horizontal, single suction multi-stage, segmented centrifugal pumps. They have the characteristics of high efficiency, wide performance range, safe and stable operation, low noise, long service life, and convenient installation and maintenance. They are used for transporting clear water or other liquids with physical and chemical properties similar to water. They can also be used for transporting hot water, oil, corrosive or abrasive media by changing the material of the flow passage components, the sealing form and adding a cooling system. The product follows the JB/T1051-93 standard "Form and Basic Parameters of Multi-stage Clear Water Centrifugal Pumps".
Structural analysis
The multi-stage pump mainly consists of four parts: stator, rotor, bearing and shaft seal:
1. The stator part of the multi-stage pump is mainly composed of the suction section, middle section, discharge section and guide vanes, and the sections are clamped together by tightening bolts to form the working chamber. For D-type pumps, they are generally horizontally sucked and vertically discharged; when used for water injection in oil fields, the pump inlet and outlet are all vertically upward. For DG-type multi-stage pumps, the outlet and inlet are both vertically upward.
2. The rotor part of the multi-stage pump is mainly composed of the shaft, impeller, balance disk and shaft sleeve. The axial force is balanced by the balance disk.
3. The bearing of the multi-stage pump mainly consists of bearing body, bearing and bearing cover, and the bearing is lubricated with grease or thin oil.
4. The shaft seal of the multi-stage pump adopts soft packing seal, which is mainly composed of the water seal water from the suction section and the sealing case on the tail cover, the packing, the water retaining ring, etc. For D-type pumps, the water seal water comes from the pressure water in the pump. For DG-type pumps, the water seal water comes from external water supply.
5. The rotation of the multi-stage pump. The pump is driven directly by the prime mover through an elastic coupling. From the perspective of the prime mover, the pump rotates clockwise. D and DG-type pumps are horizontal single suction multi-stage segmented centrifugal pumps. They are used for transporting clear water (containing impurities less than 1% and particle size less than 0.1mm) or other liquids with physical and chemical properties similar to water. D-type pumps are used for transporting media with a temperature less than 100℃, suitable for mine drainage, oil field water injection, factory and urban water supply and drainage in various occasions. Oil field water injection pumps are made of different materials according to the corrosiveness of the medium. DG-type pumps are used for transporting media with a temperature less than 120℃, suitable for various boiler feed water.

The basic structure of a multistage pump consists of the inlet section, outlet section, middle section, tail cover, impeller, pump body, pump shaft, bearings, sealing ring, stuffing box, etc.
1. The impeller is the core part of the multistage pump. It has a higher rotational speed and greater power. The blades on the impeller play a major role. Before assembly, the impeller must undergo static balance testing. The inner and outer surfaces of the impeller should be smooth to reduce water flow friction loss.
2. The inlet section, outlet section, and middle section are also called the pump casing. It serves as the main body of the multistage pump, providing support and fixation, and connecting with the bearing support bracket.
3. The function of the pump shaft is to connect the pump shaft with the motor through a coupling, transmitting the torque from the motor to the impeller. Therefore, it is the main component for transmitting mechanical energy.
4. Bearings are components that support the pump shaft and are made of rolling bearings or sliding bearings. Rolling bearings use butter as the lubricant and should be filled appropriately, generally 2/3 to 3/4 of the volume. Too much will cause overheating, while too little will result in noise and overheating and cause damage. Sliding bearings use transparent oil as the lubricant, and the oil level should be at the oil level line. Too much oil will seep out along the pump shaft and float away, while too little will cause the bearing to overheat and burn out, resulting in accidents. During the operation of the water pump, the temperature of the bearing is usually the highest at 85 degrees Celsius, generally operating at around 60 degrees Celsius. If it is too high, the cause should be investigated (whether there are impurities, whether the oil quality is black, whether water is entering), and it should be dealt with in time.
5. The sealing ring is also known as the leakage reduction ring. If the gap between the impeller inlet and the pump casing is too large, it will cause water in the high-pressure area of the pump to flow through this gap to the low-pressure area, affecting the water output and efficiency of the pump. If the gap is too small, it will cause friction between the impeller and the pump casing, resulting in wear. To increase the backflow resistance and reduce internal leakage, and to delay the service life of the impeller and pump casing, a sealing ring is installed at the joint between the inner edge of the pump casing and the outer edge of the impeller. The sealing gap should be maintained between 0.25 and 1.10 mm.
6. The stuffing box is mainly composed of packing, water seal ring, packing cylinder, packing cover, and water seal pipe. The main function of the stuffing box is to seal the gap between the pump casing and the pump shaft, preventing water from flowing out of the pump and air from entering the pump. It maintains the vacuum inside the pump. When the pump shaft and the packing rub against each other and generate heat, the water seal pipe will hold the water in the water seal ring to cool the packing. This ensures the normal operation of the pump. Therefore, during the routine inspection of the pump operation, the inspection of the stuffing box is particularly important. After about 600 hours of operation, the packing should be replaced.
7. Multistage pumps that can change the inlet and outlet directions

Multi-stage pumps are a type of centrifugal pumps, and they also obtain centrifugal force through the rotation of the impeller to convey materials. When the density of the gas reaches the working range of the mechanical vacuum pump, it will be extracted, thereby gradually achieving high vacuum.
Multi-stage pumps can be used in many industrial sectors such as petroleum, chemical industry, machinery, mining, light industry, medicine, and food. In many industrial production processes, such as vacuum filtration, vacuum water supply, vacuum feeding, vacuum evaporation, vacuum concentration, vacuum rehumidification, and vacuum degassing, multi-stage pumps are widely applied. They can remove flammable and explosive gases, and in addition, they can also remove dusty and water-containing gases. Therefore, the application of water ring pumps is increasing.