The operation process and precautions of single-stage centrifugal pump

 1. Operational process

 Prepare before starting  

Check the equipment: check whether the appearance of the pump body and motor is damaged, whether the anchor bolts are tight, and whether the coupling connection is good. Check whether the pump shaft rotates flexibly and whether there is any jamming.

Check lubrication and sealing: ensure that the lubricating oil level in the bearing box is within the normal range, the oil quality is good, and there is no deterioration and emulsification. Check that there are no leaks in the mechanical seal or packing seal and that the sealing gland is installed correctly.

Check the pipeline: confirm that the suction line and the discharge line are firmly connected, there is no leakage, and the valve is in the correct opening and closing state. The valves on the suction line should be fully open, and the valve on the discharge line should be closed.

Filling and pumping exhaust: Open the valve of the suction line, fill the pump with liquid, and open the exhaust valve on the pump body at the same time to drain the air in the pump until the liquid continues to flow out and then close the exhaust valve. For pumps that convey hot water or easily vaporized liquids, special attention should be paid to preventing vaporization during the pump filling process.

 2. Launch

Start the motor: Press the start button to start the motor. Observe whether the starting current and running current of the motor are within the normal range, listen to whether the running sound of the pump and motor is normal, and whether there is abnormal vibration and noise.

Slowly open the outlet valve: After the pump runs smoothly, gradually and slowly open the valve on the discharge pipeline, and observe the pressure, flow, current and other parameters of the pump at the same time to make it reach the normal working state. It is strictly forbidden to run the pump for a long time with the outlet valve closed, so as to avoid the temperature of the liquid in the pump rising and damaging the pump body.

3. Operational monitoring   

Parameter monitoring: Regularly observe the inlet and outlet pressure, flow, motor current, temperature and other parameters of the pump to ensure that these parameters operate within the specified range. If abnormal parameters are found, the cause should be analyzed in time and corresponding measures should be taken.

Equipment status checks: Frequently check the operation of pumps and motors, including vibration, noise, bearing temperature, and whether there are leaks in the seals. The bearing temperature should generally not exceed 70 °C, if the temperature is too high, it should be stopped in time for inspection.

Liquid level monitoring: For systems with liquid level requirements, it is necessary to pay close attention to the liquid level of the suction tank or pool to prevent the liquid level from being too low and causing the pump to be evacuated and affecting the normal operation of the pump.

4. Parking

Close the outlet valve: Gradually close the valve on the discharge line, and then press the stop button to stop the motor from running.

Close the inlet valve: Close the valve on the suction line to prevent the liquid from backflowing. For pumps that convey medium that is easy to crystallize and coagulate, the medium in the pump and pipeline should be drained in time after stopping to prevent blockage. -

Cleaning and maintenance: clean the pump body and surrounding environment to keep the equipment clean. According to the maintenance requirements of the equipment, the pump should be maintained regularly, such as replacing the lubricating oil, cleaning the filter, checking the seals, etc.

5. Precautions

5.1. Prevent cavitation: ensure that the installation height of the pump meets the requirements, avoid excessive resistance of the suction pipeline, and prevent the liquid from vaporizing at the inlet of the pump and causing cavitation. Cavitation can damage the impeller and pump body, reducing pump performance and life.

5.2. Avoid dry running: In any case, avoid dry running of the pump in a liquid-free state, otherwise it will cause damage to mechanical seals, bearings and other components due to lack of lubrication and cooling.

5.3. Control the operating parameters: operate in strict accordance with the rated parameters of the pump, and do not operate with overpressure, overflow and current, so as not to damage the equipment. If it is necessary to adjust the flow rate, reasonable adjustment methods should be adopted, such as changing the speed, adjusting the valve opening, etc., but care should be taken to avoid the pump running in an inefficient area.

5.4. Pay attention to the characteristics of the medium: understand the properties of the conveyed medium, such as temperature, viscosity, corrosiveness, particle size, etc., select the appropriate pump type and material according to the characteristics of the medium, and take corresponding protective measures. For corrosive media, corrosion-resistant materials should be used to manufacture the overflow parts of the pump; For media containing particles, care should be taken to prevent particles from wearing out the impeller and seals.

5.5. Regular maintenance: Formulate a detailed maintenance plan, regularly inspect, clean, lubricate, fasten and other maintenance work on the pump, find and deal with potential problems in time, and prolong the service life of the pump. At the same time, it is necessary to do a good job in the operation and maintenance records of the equipment, so as to analyze the operation status of the equipment and the cause of failure.

5.6. Safe operation: During the operation, strictly abide by the safety operation procedures and wear the necessary personal protective equipment. When the pump is running, it is strictly forbidden to carry out maintenance and adjustment work, if maintenance is required, the power supply must be cut off first, and the "no closing" sign must be hung to ensure the safety of maintenance personnel.

Single-stage centrifugal pumps have the advantages of simple structure, reliable performance, wide flow and head range, etc., and have a wide range of applications in many fields, the following are some practical application cases:

1. Agricultural irrigation

Case background: A large farm in the North China Plain planted a large number of wheat, corn and other crops. Precipitation is unevenly distributed in the region, with large seasonal variations, so reliable irrigation systems are needed to keep crops growing.

Solution: The farm chose a single-stage centrifugal pump as the core equipment of the irrigation system. The pump is installed near an irrigation source (e.g., river, well), and the water is introduced into the pump through a suction line, which is then transported to the irrigation channel or sprinkler irrigation system in the field through the discharge line.

Application effect: The single-stage centrifugal pump has a large flow rate and can meet the irrigation needs of a large area of farmland. The head can be selected according to the topography and irrigation requirements of the farm, ensuring that the water can reach the individual fields smoothly. The stable operation of the pump ensures that the crops can get sufficient water in the dry season, and improves the yield and quality of the crops.

2. Urban water supply

Case background: The water supply system of a medium-sized city needs to transport water from the reservoir to various areas of the city to meet the water needs of residents, industrial production and public facilities.

Solution: Multiple single-stage centrifugal pumps were installed in the pumping station of the reservoir, which were operated in parallel or series to meet the needs of different water consumption. These pumps pump water out of the reservoir, treat it at a water treatment plant, and then deliver it to individual users through the city's water supply network.

Application effect: The single-stage centrifugal pump has stable operation, low maintenance cost, and can operate continuously for a long time, ensuring the reliability of urban water supply. Its efficient performance also helps to reduce water supply costs while meeting the city's growing water demand.

3. Industrial field

Case Background: A chemical plant needs to transport a variety of chemical raw materials and finished products, which have different characteristics, such as corrosiveness, high viscosity, etc.

Solution: According to the characteristics of different media, the chemical plant selected single-stage centrifugal pumps of different materials. For corrosive media, pumps made of corrosion-resistant materials such as stainless steel or fluoroplastics are used; For high-viscosity media, a single-stage centrifugal pump with a large impeller and low speed is selected to improve the pumping capacity of the pump.

Application effect: The material selection of the single-stage centrifugal pump is flexible, and it can adapt to the transportation requirements of various chemical media. Through proper selection and configuration, these pumps play an important role in the production process of chemical plants, ensuring the continuity and stability of production, while reducing safety accidents and environmental pollution caused by problems such as media leakage.

4. Sewage treatment

Case Background: A municipal wastewater treatment plant needs to transport sewage from a collection tank to a treatment facility for purification, and then discharge or reuse the treated water.

Solution: The wastewater treatment plant uses a single-stage centrifugal pump to transport the wastewater. In order to prevent impurities in the sewage from clogging the pump body, a grid and filter are installed at the inlet of the pump. At the same time, in order to adapt to the characteristics of sewage, the impeller and casing of the pump are made of wear-resistant and corrosion-resistant materials.

Application effect: The single-stage centrifugal pump works well in the sewage treatment plant and can effectively transport sewage containing impurities and pollutants. Its stable performance ensures the normal operation of the sewage treatment process, helps to improve the efficiency of sewage treatment and reduces environmental pollution. The treated water meets the discharge standards, and part of the water is reused in areas such as urban greening and industrial cooling, realizing the recycling of water resources.