Professionals in the water pump industry often encounter a common scenario: pumps manufactured during the same period may require frequent repairs for customers in certain locations, while those in other areas operate flawlessly—sometimes for decades—without any issues. Setting aside potential variations in manufacturing quality, proper daily maintenance and care play a crucial role. Although water pump structures are not overly complex, they are prone to problems if operated for extended periods without maintenance. Today, the experts at Shanghai Shenyin Pump will briefly outline how to effectively perform daily maintenance and repairs. These practices help extend the pump's service life, reduce costs for customers, and enhance the company's reputation.
Types of Daily Maintenance and Repair
Post-Failure Repair (Reactive Maintenance)
A strategy where repairs are performed only after a significant malfunction occurs; the damaged equipment or component is removed for repair or replacement.
Characteristics:
① High repair costs and time-consuming; disrupts normal production.
② Requires stocking a wide range of spare parts and employing additional maintenance personnel to handle repairs.
Routine Maintenance
Maintenance performed on-site at scheduled intervals to repair or replace equipment before major failures occur.
① Maintenance costs are lower than those associated with post-failure repairs.
② Improper scheduling of maintenance intervals can lead to unnecessary, excessive maintenance.
Condition Monitoring
Maintenance implemented based on the actual operating status of the water supply equipment, determined by monitoring results.
Decisions regarding repair or maintenance are based on specific anomalies such as mechanical vibration, bearing temperature, or abnormal operating noise.
If a selected parameter reaches a predetermined critical threshold, the equipment is shut down for inspection and repair to prevent more serious failures.
① Clear maintenance objectives; high production efficiency.
② Requires investment in testing equipment and personnel training.
Standard Daily Maintenance Procedures
Daily Inspection Tasks
① Check if the pump discharge pressure is normal.
② Monitor the pump for abnormal noise, vibration, and bearing temperature during operation.
③ Inspect the pump casing and auxiliary piping for leaks.
④ Check the coupling guard for looseness.
⑤ Check lubricating oil levels and seal cooling water flow.
⑥ Keep the equipment clean.
⑦ Report any abnormalities to the dispatch/control center.
Monthly Maintenance Procedures
① Define the monthly maintenance tasks. ② Perform statistical analysis on machinery and pump condition monitoring data to analyze operational trends.
③ Maintain accurate maintenance and repair records.
Quarterly Maintenance Procedures
① Check the alignment of the pump and motor; axial misalignment must be less than 0.05 mm, and angular misalignment must be less than 0.05 mm.
② Compile quarterly equipment operational data and analyze operational trends.
③ Prepare equipment failure analysis reports.
④ Measure pump casing thickness.
Annual Maintenance Procedures
① Confirm the execution of annual preventive maintenance for centrifugal pumps.
② Perform scheduled maintenance based on quarterly equipment condition data:
③ Dismantle the pump for inspection; visually inspect the pump casing for corrosion and mechanical damage, and determine whether to repair or replace it based on the extent of the damage;
④ Inspect wear rings for corrosion and wear, and measure clearances; replace if clearances are excessive;
⑤ Inspect the pump shaft and key for corrosion, wear, and deformation;
⑥ Inspect bearings; check the inner and outer races as well as the rolling elements for signs of metal fatigue;
⑦ Inspect the impeller for corrosion, wear, and signs of cavitation;
⑧ Inspect the lock nut and carefully examine the threads;
⑨ Replace the mechanical seal; inspect the shaft sleeve and replace it if the fit clearance is excessive or the surface is worn.
Maintenance of bearing grease
① Bearing re-lubrication should be performed during scheduled equipment shutdowns and carried out at regular intervals.
② Remove old grease and wipe the grease nipple clean before adding new grease.
③ After cleaning, replenish with fresh grease of the same type.
④ Grease fill level in the housing: 1/3 to 2/3 of the capacity.
Maintenance of oil-lubricated bearings
1. Lubricating oil inspection: 1) Regularly check the oil level and oil quality.
2) Lubricating oil inspection:
If the sample appears cloudy or hazy, the oil has emulsified.
If the sample has darkened in color or thickened, it may indicate that the oil has begun to carbonize. 2. Lubricating oil replacement: Replacement requirements: Flush the oil circuit with fresh lubricating oil. When replacing the oil, ensure the new oil is of the same type as the old oil and fill to the required level. Strict adherence to three-stage filtration is mandatory.
Replacement cycle: For oil-bath lubrication systems, if the oil temperature is below 60°C and the oil is uncontaminated, a once-yearly oil change is sufficient. If the oil temperature is between 60°C and 100°C, the oil must be changed four times a year.