The multi-stage pump is a type of centrifugal submersible pump that has a connecting rod that joins the inlet, exit, and center parts of the pump together. The resulting water pressure can be very significant and is dependent on the rotation of the wheel in order to get the requisite centrifugal force in order to retrieve the material. It is pushed out as the gas density reaches the operational range of the mechanical vacuum pump; this allows for the progressive achievement of a high vacuum. Because the multistage pump utilizes a variable volume centrifugal pump design in order to produce suction, pressure, and exhaust, it can be referred to as a variable volume centrifugal pump. An input section, an exit section, an intermediate section, a back cover, an impeller, a pump body, a pump shaft, a bearing, a sealing ring, a stuffing box, and other components make up the fundamental framework of the multistage pump. 
- The multistage pump's rotating part, known as the impeller, is at its heart.
- Both its speed and its output are extremely high.
- The blades of the turbine are an essential component.
- Before it can be assembled, the wheel needs to be put through a static balance test.
- To cut down on the friction loss caused by the flow of water, both the inner and outer surfaces of the fan need to be smooth.
- The pump body, which is also referred to as the inlet section, the output section, and the middle part, is the primary body of the multistage pump.
- Participate in the support and the fastening, and maintain communication with the support so that the bearing can be installed.
- Because the pump shaft is the primary component that is responsible for transmitting mechanical energy, its primary role is to link the motor to the coupling and to convey torque from the motor to the impeller.
- The bearing is a sleeved component that is attached to the pump shaft and has the purpose of providing support for the pump shaft.
- There are two different kinds of bearings: standard bearings and other varieties.
- Grease is used as a lubricant to ensure that bearings are properly grouted. Typically, 2/3 to 3/4 of the volume is too large to generate heat, but 1/3 to 1/2 of the amount will generate both noise and heat.
- For ordinary bearings, the recommended lubricant is clear oil; thus, you should fill the bearing up to the indicated level.
- When there is an absurd amount of oil, it will leak along the pump shaft and slide down; when there is an inadequate amount of oil, the bearing may overheat and burn, which can lead to accidents.
- Bearing temperatures can reach 85 degrees while the pump is operating, which is significantly higher than the average operating temperature of roughly 60 degrees.
- If it is high, investigate the potential causes (such as whether there are pollutants in the oil or whether it has leaked into the water) and begin treatment as soon as possible.
- The sealing ring, also known as the leakage reducing ring, is another name for this component. Because of the size of the gap that exists between the inlet of the impeller and the pump body, water from the high-pressure area of the pump is able to flow into the low-pressure area of the pump through this gap.
- This has the effect of diminishing the efficiency of the pump and affecting the water outlet.
- When the clearance is too tight, the friction that occurs between the pump body and the impeller will produce wear on the pump.
- A sealing ring is installed at the junction of the inner edge of the pump casing and the bracket outside the wheel.
- This is done in order to increase the resistance to backflow, reduce internal leakage, and prolong the life of the impeller and pump cover.
- The gap between the sealing ring and the bracket outside the wheel should be between 0.25 and 1.10 millimeters.
- The stuffing box is primarily made up of packaging, a water-sealing ring, a packing tube, a stuffing box, and a water-sealing tube.
- The primary purpose of the packing box is to close off the space between the pump body and the pump shaft, thereby preventing the water inside the pump from leaking out and air from the surrounding environment from getting inside the pump.
- Always ensure that the vacuum cleaner is inside the pump! In situations when heat is produced as a result of friction between the pump shaft and the packing, the seal will flow water through the sealing ring to cool the packing. Ensure that the pump is operating normally at all times.
- As a result, during the journey inspection of the pump function, the special focus ought to be directed toward verifying the packing box.
- After 600 hours of continuous operation, the packing needs to be changed.
- The multistage pump has a switch that allows it to alternate between suction and discharge.
If we want to categorize the multistage pump, we can do it like the following. There are many different series of multistage pumps, which, based on their outward presentation, can be categorized as either vertical multistage pumps or horizontal multistage pumps. 
It is possible to categorize it as a stainless-steel multistage pump, an LG-type multistage pump, or a D-type multistage pump, depending on the material it was constructed. The primary distinction between a multistage pump and a single-stage pump is the number of stages.
- A pump is considered to have multiple pumps if it has two or more impellers, and the peak head on such a pump can be greater than 125 meters.
- A single-stage pump is a pump that only has one impeller and can provide a head of 125 meters at its highest capacity.
The multistage pump series includes the LG type multistage pump, the DL type vertical multistage pump, the D type multistage pump, and the MD type multistage pump.