Multi-stage pump can be used in many industrial sectors such as petroleum, chemical industry, machinery, mining, light industry, medicine and food. One of the advantages of multi-stage pump is that it has a high pressure lifting capacity. As each series can increase the pressure of the fluid, multi-stage pump can reach a higher output pressure, so as to meet the needs of specific industries or processes. In addition, multi-stage pump can also provide a relatively stable pressure output, pressure fluctuations during fluid delivery are reduced. BelowHunan Sanchang Pump Co., Ltd.To introduce what is called multi-stage pump, multi-stage pump basic structure.

What is a multi-stage pump?

Multi-stage pump is a commonly used industrial equipment for conveying liquid or gas. It has multiple stages, each stage is equipped with one or more impellers. Multi-stage pumps are usually composed of a main pump and multiple auxiliary pumps. It works in a cascade manner. Its working principle is to pressurize the liquid or gas step by step through the action of impellers at all levels, and finally deliver it to the required location.

The multi-stage pump is a centrifugal pump combined with the water inlet and outlet section and the middle section through a pull rod. Its output water pressure can be very large, and it also relies on the rotation of the impeller to obtain centrifugal force, so that the material is pumped out when the gas density reaches the working range of the mechanical vacuum pump, thus gradually obtaining a high vacuum. The multi-stage pump realizes suction, compression and exhaust by the change of the volume of the pump chamber, therefore, it is a centrifugal pump with variable volume.

Basic structure of multistage pump

The basic structure of the multi-stage pump is composed of the inlet section, the outlet section, the middle section, the tail cover, the impeller, the pump body, the pump shaft, the bearing, the seal ring, the stuffing box and other components.

1. The impeller is the core part of the multi-stage pump. Its speed is higher than the force, and the blades on the impeller play a major role. The impeller must pass a static balance experiment before assembly. The inner and outer surfaces of the impeller are required to be smooth to reduce the friction loss of the water flow.

2. The inlet section, outlet section and middle section are also called pump casing, which is the main body of multi-stage pump. It plays a supporting and fixing role and is connected with the bracket for installing the bearing.

3. The function of the pump shaft is to connect the coupling with the motor to transmit the torque of the motor to the impeller, so it is the main component for transmitting mechanical energy.

4. The bearing is a component that is sleeved on the pump shaft to support the pump shaft. There are two kinds of rolling bearings and sliding bearings. Rolling bearings use butter as lubricant to add oil. Generally, 2/3~3/4 of the volume is too much, which will generate heat, too little noise and heat. Sliding bearings use transparent oil as lubricant, and add oil to the oil level line. Too much oil will seep out and drift along the pump shaft, and too little bearing will overheat and burn out to cause accidents. During the operation of the pump, the temperature of the bearing is as high as 85 degrees and generally runs at about 60 degrees. If it is too high, the cause (whether there are impurities, whether the oil is black, whether there is water) should be found and treated in time.

5. The sealing ring is also called leakage reduction ring. The gap between the impeller inlet and the pump casing is too large, which will cause the water in the high-pressure area of the pump to flow to the low-pressure area through this gap, which will affect the water output of the pump and reduce the efficiency. If the gap is too small, it will cause friction and wear between the impeller and the pump casing. In order to increase the backflow resistance to reduce internal leakage, delay the service life of the impeller and the pump casing, the inner edge of the pump casing and the impeller is equipped with a sealing ring, and the sealing gap is maintained between 0.25~1.10mm.

6. The stuffing box is mainly composed of packing, water seal ring, packing cylinder, packing gland and water seal pipe. The function of the stuffing box is mainly to close the gap between the pump casing and the pump shaft, so that the water in the pump does not flow to the outside or the outside air enters the pump. Always maintain the vacuum in the pump! When the pump shaft and packing friction to generate heat, it is necessary to rely on the water seal pipe to the water seal ring to cool the packing! Maintain the normal operation of the pump. Therefore, special attention should be paid to the inspection of the stuffing box during the operation of the pump, and the packing should be replaced after about 600 hours of operation.

Multistage pumps are widely used in many fields. For example, it is often used in water treatment systems to provide high-pressure water, feed water equipment and meet the needs of specific processes. In addition, multi-stage pumps are also widely used in petroleum, chemical, electric power and other fields, used to transport fuel, lubricating oil, acid and alkali and other media.

When choosing a multi-stage pump, many factors need to be considered. The first is the nature and requirements of the transport medium. Different media have different requirements on the material and sealing requirements of the pump, and it is necessary to select the appropriate pump type and material. The second is the need to consider the flow and pressure of the delivery. Determine the number of stages and power required for the multistage pump according to actual needs. In addition, pump reliability, ease of maintenance and economy need to be considered.

In short, the multi-stage pump is an important industrial equipment with high pressure lifting capacity and stable pressure output characteristics. It has a wide range of applications in many fields and can meet the needs of various media transportation. Choosing the right multi-stage pump needs to consider a variety of factors to meet the requirements of a specific process or industrial process.