Regular Maintenance Of Pipeline Pumps - By Mastering These Steps, You'll Become An Expert!

Pump pipes are commonly used fluid transportation equipment in both industrial and civil sectors. Their stable operation relies on scientific and reasonable maintenance. The following details the maintenance methods of pump pipes from aspects such as daily inspection, regular maintenance, fault prevention, and handling of special situations:
I. Inspection and Maintenance during Daily Operations
Daily inspections are crucial for identifying problems promptly and preventing the expansion of faults. They should be conducted both during the operation of the pump and after it has been shut down.
Real-time monitoring during operation
Operating parameters: Through the dashboard or control system, monitor the inlet and outlet pressures, flow rate, current, voltage, etc. of the pump in real time to ensure they are within the rated range. If the pressure drops suddenly, it may be due to a blocked pipeline or a damaged impeller; if the current is too high, it may be caused by an overloaded motor or a bearing fault.
Sound and Vibration: A properly functioning pipeline pump should have no abnormal noises and steady vibration. If there is a "buzzing" sound, it might indicate a phase deficiency in the motor; a "frictional sound" could be due to the rubbing between the impeller and the pump casing; severe vibration could be caused by misalignment of the coupling, loose anchor bolts, or imbalance of the impeller.
Temperature: Touch the motor housing and bearing areas with your hand. The temperature should not exceed 60℃ (when the ambient temperature is 30℃). If it feels hot, it may be due to poor lubrication of the bearings, short circuit of the motor winding, or malfunction of the cooling fan.
Sealing condition: Check if there is any leakage at the mechanical seal or packing seal. The mechanical seal allows for a small amount of leakage (1-2 drops per minute), but if it leaks in a continuous stream, the machine needs to be shut down for maintenance; if the leakage of the packing seal is too large, the retaining ring can be tightened appropriately, but not too tightly, to avoid burning the packing.
II. Regular Maintenance (The maintenance cycle is determined based on the operating frequency, such as weekly, monthly, or quarterly)
Cleaning and appearance inspection
Clean the dust, oil stains and debris from the pump body and the surface of the motor to ensure good heat dissipation.
Check the sealing performance of the pump body and the connection flanges of the pipelines, for any cracks or corrosion; check if the bolts are loose and tighten them promptly if necessary.
2. Maintenance of the lubrication system
Bearings lubrication: Depending on the model of the pump, add or replace the lubricating oil/lubricating grease (such as calcium-based grease, mechanical oil) regularly. When adding, clean the oil injection port to prevent impurities from entering; the oil level should be maintained at 1/2 - 2/3 of the oil gauge, neither too much nor too little.
If lubricating oil is used, it is necessary to regularly check the quality of the oil. If it becomes emulsified, darkened, or contains impurities, it should be completely replaced and the oil chamber cleaned.
3. Inspection of impeller and flow channel
After the machine is shut down, open the pump cover and check if the impeller is worn, cracked or if the gap between the impeller flange is too large (the normal gap is generally 0.1-0.5mm. If it exceeds the standard, the impeller or the flange needs to be replaced).
Remove debris (such as sand and fibers) from the flow channel to prevent blockages that could lead to reduced flow or damage to the impeller.
4. Inspection of Motors and Electrical Systems
Check the insulation resistance of the motor windings (measured with a multimeter, the insulation resistance between phases and to ground should be ≥ 0.5 MΩ). If it is below the standard, it needs to be dried or repaired.
Check whether the connection terminals are loose or oxidized, and whether the wires are aged; ensure that the control switch and the protector are functioning properly to guarantee electrical safety.
5. Replacement of Sealing Parts
Mechanical seal: If there is excessive leakage, failure of the spring, or wear of the moving or static rings, the mechanical seal needs to be replaced as a whole. Also, be sure to keep the end faces clean and parallel during installation.
Packing seal: Replace the packing (such as asbestos rope, polytetrafluoroethylene packing) regularly. When replacing, it should be wound layer by layer, with the cut edges forming a 45° angle. The cut edges of adjacent layers should be offset by 120°. The tightness should be appropriate so that the leakage meets the standard.
III. Maintenance after Long-Term Shutdown
If the pipeline pump needs to be out of use for a long period of time (more than 1 month), the following protective measures should be taken:
Remove all the media from the pump and the pipelines. If the liquid being transported is corrosive, it should be thoroughly rinsed with clean water to prevent internal corrosion.
Remove the pump cover, dry the impeller, pump housing and other components, and apply anti-rust oil; add new lubricating grease to the bearings, and dry and seal the motor windings after they are cooled.
Close the inlet and outlet valves, take measures to protect the pump body from dust and moisture (such as covering it with plastic sheeting), and conduct regular inspections of the equipment condition.
IV. Common Fault Prevention and Handling
Fault phenomenon Possible cause Preventive and handling measures
Unable to start. Power failure, motor damage, impeller stuck. Check the power voltage and wiring; clean the impeller of debris; repair or replace the motor.
Insufficient flow, blocked pipeline, worn impeller, air leakage at the inlet. Clean the pipeline and the impeller; replace the impeller; inspect the inlet seal and remove the air.
Motor overheating, overload, bearing failure, poor heat dissipation. Reduce load; replace bearings; clean heat sinks and check fans.
Severe vibration: Misalignment of the coupling, unbalance of the impeller. Realign the coupling; correct or replace the impeller.
V. Maintenance Precautions
All maintenance operations must be carried out under the condition of equipment shutdown and power disconnection to ensure safety.
When disassembling and installing the components, make proper markings (such as the direction of the impeller and the position of the bolts) to avoid incorrect assembly.
When replacing the spare parts, select genuine parts that match the original model to ensure the stability of the pump's performance.
Establish a maintenance record ledger, documenting the time, content of each inspection and maintenance, as well as the handling of any faults, to provide a reference for subsequent maintenance.
Through the above systematic maintenance measures, the service life of the pipeline pump can be effectively prolonged, the downtime due to faults can be reduced, and its efficient and stable operation can be ensured.