What Maintenance Measures Can Extend The Service Life Of Centrifugal Pumps?

Nov 10, 2025

 

1. Introduction

 

Centrifugal pump is a fluid conveying equipment widely used in industrial, agricultural, municipal and other fields. It has the advantages of simple structure, convenient operation, and high efficiency. However, in the long-term operation of centrifugal pumps, their performance will gradually decline and their service life will be shortened due to various factors such as wear, corrosion, and cavitation. Therefore, taking effective maintenance measures is crucial for extending the service life of centrifugal pumps.

2, Daily maintenance measures

(1) Regular inspection

 

Visual inspection

 

Every day, the centrifugal pump should be visually inspected to see if there are any leaks, deformations, cracks, or other issues with the pump body. Check if the inlet and outlet flanges, sealing parts, bolts, and other connecting parts of the pump are tightened. If there is any looseness, tighten them in a timely manner. At the same time, check whether there is corrosion on the surface of the pump body, and if corrosion is found, it should be treated in a timely manner.

 

Run parameter check

 

Regularly check the operating parameters of centrifugal pumps, including flow rate, head, current, voltage, etc. Flow and head can be measured by instruments installed on pipelines, while current and voltage can be monitored by electric meters. Compare the measurement results with the rated parameters of the pump. If significant deviations are found, the cause should be promptly identified and adjusted. For example, if the flow rate is lower than the rated flow rate, it may be caused by impeller blockage, inlet pipe blockage, or seal ring wear.

 

(2) Lubrication maintenance

 

Identification of lubrication parts

 

The bearings of centrifugal pumps are the parts that require special lubrication. The lubrication parts of different types of centrifugal pumps may vary. Generally speaking, the bearing box of a horizontal centrifugal pump is equipped with bearings, and the main shaft bearings of a vertical centrifugal pump also require lubrication. In addition, some centrifugal pump couplings and other parts may also require lubrication.

 

Selection and replacement of lubricants

 

Select the appropriate lubricant based on the working conditions and bearing type of the centrifugal pump. For high-speed running bearings, lubricating oil is generally used; For low-speed heavy-duty bearings, lubricating grease can be used. The viscosity of lubricating oil should be selected according to the working temperature, and lubricating oil with higher viscosity should be selected when the temperature is high.

 

 

The penetration of lubricating grease should be selected according to the working load of the bearing and the ambient temperature. Regularly replace lubricants, with a general replacement cycle of 3-6 months for lubricating oil and 6-12 months for lubricating grease. When replacing lubricants, the old lubricant should be cleaned first before adding new lubricant.

 

(3) Sealing maintenance

 

Sealing type and inspection

 

The seals of centrifugal pumps are divided into two types: mechanical seals and packing seals. For mechanical seals, regular checks should be conducted on the wear of the sealing end face, the fit of the dynamic and static rings, and the integrity of the sealing ring. During inspection, it is possible to determine if the seal is functioning properly by observing if there is any leakage at the sealing point. For packing sealing, the tightness and wear of the packing should be checked. Loose packing can cause leakage, while tight packing can increase shaft friction and affect pump efficiency.

 

Seal replacement

 

When the dynamic and static rings of the mechanical seal are severely worn, the sealing ring is damaged, or the packing is worn to a certain extent, the seal should be replaced in a timely manner. When replacing the mechanical seal, choose the same type of seal as the original seal and install it according to the correct installation steps. When replacing the packing, suitable packing materials should be selected, such as graphite packing, flexible graphite packing, etc., and installed according to the specified packing pressure.

 

3, Regular maintenance measures

 

(1) Disassembly inspection

 

Dismantling cycle

 

According to the operating time and working conditions of the centrifugal pump, it is generally necessary to disassemble and inspect the centrifugal pump every 1-2 years of operation or after a cumulative operation of 2000-4000 hours. For centrifugal pumps with harsh working conditions and long operating times, the disassembly inspection cycle should be appropriately shortened.

 

Disassembly inspection content

 

During disassembly inspection, the wear of components such as impellers, pump shafts, bearings, and sealing rings should be carefully checked. The wear of impellers mainly manifests as blade erosion, corrosion, and cavitation pits. The wear of the pump shaft mainly occurs at the neck of the shaft, which may cause changes in the concentricity of the shaft. The wear of bearings can affect the rotational accuracy and stability of the pump. The wear of the sealing ring can lead to an increase in leakage. For severely worn components, they should be repaired or replaced in a timely manner.

 

(2) Component repair and replacement

 

Impeller repair

 

If the wear of the impeller is light, repair methods such as welding and repair can be used. Before welding, the impeller should be preheated, and after welding, insulation and slow cooling treatment should be carried out to prevent cracking of the impeller. If the wear of the impeller is severe, such as a large area of blade damage or deformation, a new impeller should be replaced. When replacing the impeller, choose the same model as the original impeller and ensure the installation accuracy of the impeller.

 

Pump shaft repair and replacement

 

For slight wear of the pump shaft, methods such as chrome plating and spraying can be used for repair. If the pump shaft is bent or deformed, it should be straightened. When the pump shaft is severely worn or cracked, a new pump shaft should be replaced. When replacing the pump shaft, it should be ensured that the material, size, and accuracy of the pump shaft are the same as the original pump shaft.

 

Bearing replacement

 

When the bearing wears out to a certain extent, a new bearing should be replaced. When replacing bearings, choose bearings of the same model as the original bearings and install them according to the correct installation steps. When installing bearings, pay attention to the cleanliness and lubrication of the bearings to avoid impurities entering the interior of the bearings.

 

(3) Rust prevention and anti-corrosion treatment

 

Rust prevention treatment

 

During the disassembly inspection of centrifugal pumps, rust prevention treatment should be carried out on metal components such as the pump body, impeller, and pump shaft. For components that are temporarily not installed, they should be coated with anti rust oil or anti rust paint. For components that have already rusted, rust removal treatment should be carried out first, followed by rust prevention treatment. The rust removal methods can include manual rust removal, mechanical rust removal, or chemical rust removal.

 

Anti-corrosion treatment

 

For centrifugal pumps working in corrosive media, anti-corrosion treatment should be carried out. Methods such as lining, coating, or using corrosion-resistant materials to manufacture pump components can be used for corrosion prevention. For example, in centrifugal pumps that transport corrosive media such as acids and alkalis, rubber lining or fiberglass lining can be used to protect the pump body. For components such as impellers and pump shafts, corrosion-resistant materials such as stainless steel or alloy steel can be used for manufacturing.

 

4, Operating environment maintenance

 

(1) Temperature control

 

Cooling system maintenance

 

For centrifugal pumps operating in high-temperature environments, it is important to ensure that the cooling system is functioning properly. Regularly check whether the cooling water pipeline is unobstructed and whether the cooling water flow is normal. If the cooling water pipeline is blocked or the cooling water flow is insufficient, the pipeline should be cleaned or the cooling water system adjusted in a timely manner.

 

 

At the same time, it is necessary to check the heat transfer efficiency of the cooler. If scaling or a decrease in heat transfer efficiency is found in the cooler, it should be cleaned or replaced in a timely manner.

 

Thermal insulation measures

 

Centrifugal pumps working in cold environments should be insulated. Insulation materials can be used to wrap the pump body to prevent the liquid inside the pump from freezing. At the same time, the integrity of the insulation layer should be checked, and if any damage is found, it should be repaired in a timely manner.

 

(2) Humidity control

 

Moisture prevention measures

 

Centrifugal pumps working in humid environments should take moisture-proof measures. A moisture-proof layer can be installed around the pump body to prevent moisture from entering the pump body. At the same time, it is necessary to regularly check the moisture resistance of the pump body. If condensation is found on the surface of the pump body, it should be dried in a timely manner.

 

Well-ventilated

 

Ensure good ventilation around the centrifugal pump and avoid excessive temperature or humidity around the pump body. Good ventilation can lower the temperature of the pump body and reduce the occurrence of corrosion. Meanwhile, ventilation can also prevent the accumulation of harmful gases around the pump body, protecting the health of the pump body and operators.

 

5, Operating standards

 

(1) Start and Stop

 

Pre-start check

 

Before starting the centrifugal pump, a comprehensive inspection should be conducted. The inspection includes checking whether the connections of various components of the pump body are tight, whether the lubrication system is normal, whether the sealing is good, and whether the inlet and outlet valves are in the correct on/off state. At the same time, it is necessary to check whether the pump shaft rotates flexibly by turning the wheel. If the pump shaft is found to be unresponsive or stuck, the cause should be identified and the fault should be eliminated in a timely manner.

 

Start operation

 

When starting the centrifugal pump, the inlet valve should be opened first to fill the pump body with liquid, and then the motor should be started. During the start-up process, pay attention to observing the operation of the pump, such as whether the current, pressure, vibration, etc. are normal. If any abnormal situation is found, the machine should be stopped immediately for inspection.

 

Parking operation

 

When parking, the outlet valve should be closed first, and then the motor should be stopped. After the pump body stops rotating, close the inlet valve. For centrifugal pumps that have been out of service for a long time, the liquid inside the pump body should be emptied and necessary maintenance should be carried out.

 

(2) Monitoring during operation

 

Flow and head monitoring

 

During the operation of centrifugal pumps, changes in flow rate and head should be closely monitored. If abnormal fluctuations in flow or head are found, the operating parameters of the pump should be adjusted or the operating condition of the pump should be checked in a timely manner. For example, if the flow suddenly decreases, it may be caused by blockage of the inlet pipeline, wear of the impeller, or wear of the sealing ring.

 

Vibration and noise monitoring

 

Vibration and noise are important indicators of the operating status of centrifugal pumps. During normal operation of a centrifugal pump, vibration and noise should be kept within a certain range.

 

 

If there is excessive vibration or noise, it may be caused by pump shaft imbalance, bearing wear, impeller imbalance, or cavitation. Immediate shutdown inspection should be carried out to identify the cause and take appropriate measures.

 

6, Conclusion

 

Extending the service life of centrifugal pumps requires starting from multiple aspects such as daily maintenance, regular upkeep, environmental maintenance, and operating standards. By strictly implementing various maintenance measures, problems that arise during the operation of centrifugal pumps can be detected and solved in a timely manner, ensuring the normal operation of centrifugal pumps, improving their work efficiency and service life, saving production costs for enterprises, and increasing economic benefits. At the same time, it also helps to reduce the frequency of equipment maintenance and replacement, and minimize the impact on the environment.