The daily maintenance of vertical stainless steel long-shaft pumps is crucial for maintaining their good operating condition and extending their service life. Through regular maintenance and inspections, potential issues can be detected in a timely manner, and effective measures can be taken to resolve them, preventing the occurrence of faults and ensuring the stable operation of industrial circulating water systems. The specific methods and frequency of daily maintenance are as follows:
- Conduct a visual inspection of the pump every day to check for leaks, damage, or deformation in the pump body, pipelines, valves, and other components.
- Check if the pump’s operating sound is normal. If there is abnormal noise or vibration, stop the pump immediately to investigate the cause.
- Monitor parameters such as the pump’s inlet and outlet pressure, flow rate, and current, and compare them with normal operating data to determine if the pump is running properly. Generally, the pump’s operating parameters are required to fluctuate within the rated range—for example, the flow rate fluctuation should not exceed ±5%, and the pressure fluctuation should not exceed ±10%.
- Inspect the pump’s bearings every week, and measure the bearing temperature and vibration value. The bearing temperature should generally not exceed the ambient temperature by 35℃, and the maximum temperature must not exceed 80℃. The vibration value should comply with relevant standards; typically, at a rotational speed of 1800 r/min, the effective value of vibration velocity should not exceed 4.5 mm/s.
- Check the lubrication condition of the bearings to ensure the oil level of the lubricating oil is normal and the oil quality is good. If the lubricating oil is found to be deteriorated or contaminated, replace it promptly.
- Inspect the pump’s sealing device every month to check for leaks at the seal. For mechanical seals, the leakage rate should generally not exceed 5 drops per minute. If excessive leakage is found, check the wear of the sealing surface, the elasticity of the sealing spring, and the correctness of the seal installation, and replace the seal if necessary.
- Inspect the wear condition of the pump’s impeller and pump body. If any components are severely worn, repair or replace them in a timely manner.
- Clean the pump’s inlet and outlet pipelines every quarter to remove dirt, impurities, and sediments inside the pipelines, ensuring unobstructed flow.
- At the same time, check if the pipeline supports and hangers are secure. If they are loose or damaged, repair them promptly.
- Perform a comprehensive overhaul of the pump every year, including disassembling the pump body, inspecting all components for wear, corrosion, and damage, and replacing severely worn parts.
- Realign the pump’s shafting and adjust the gap and concentricity of the coupling.
- Inspect and maintain the motor, including cleaning the interior of the motor, checking the insulation condition of the windings, and replacing the brushes.
Common Faults and Troubleshooting
During the operation of vertical stainless steel long-shaft pumps, some common faults may occur and need to be resolved promptly:
① Insufficient Flow or No Water Discharge
- Possible causes: Blockages by debris on the suction side or outlet side (e.g., blockages in the filter screen, impeller, guide vane body, discharge pipe, or valve system).
Solution: Stop the pump to clean these components and remove the blockages.
- Possible causes: Excessive wear of the seal ring, leading to increased internal leakage of the pump and affecting flow.
Solution: Replace the seal ring.
- Other causes: Impeller damage, incorrect rotation direction, low voltage, or insufficient submergence depth (resulting in air suction).
Solutions: Replace the impeller, correct the rotation direction, measure the voltage and frequency to inspect the motor, or increase the suction water level, respectively.
② Abnormal Vibration and Noise
- Possible causes: Low suction water level or excessively open outlet gate valve, leading to pump cavitation.
Solution: Increase the suction water level or reduce the opening of the outlet gate valve.
- Possible causes: Imbalance of the impeller.
Solution: Correct the static balance of the impeller.
- Possible causes: Excessive deviation in the concentricity of the shaft (causing additional stress during pump operation and leading to vibration).
Solution: Correct the concentricity of the shaft and straighten the shaft.
- Possible causes: Loose anchor bolts (resulting in unstable pump operation and vibration/noise).
Solution: Tighten the anchor bolts.
- Possible causes: Worn or damaged bearings.
Solution: Replace the bearings.
③ Excessively High Bearing Temperature
- Possible causes: Poor lubrication (e.g., insufficient, deteriorated, or contaminated lubricating oil).
Solution: Replenish or replace the lubricating oil promptly.
- Possible causes: Improper bearing assembly (e.g., excessively small or large clearance).
Solution: Readjust the assembly clearance of the bearings.
- Possible causes: Excessive pump load (e.g., excessively high flow rate or head, increasing the pressure on the bearings).
Solution: Adjust the flow rate and head to reduce the load.