What are the key points for chemical process pump maintenance?

Daily (10 minutes at shift change)

1. Check the liquid level: The tank liquid level should be ≥30% to prevent dry grinding. If the liquid level drops suddenly, check for leaks first.

2. Listen for sounds: No metal friction or cavitation noise. Immediately reduce the load if any abnormality occurs.

3. Feel the temperature: Bearing seat ≤70°C, mechanical seal gland ≤60°C; if hot, cool with water first.

4. Check for leaks: Mechanical seal, flange, and hose. If visible leakage is >3 drops/minute, address it.

5. Record the pressure: Compare the outlet pressure with the previous day's pressure. If the fluctuation is >±5%, check the filter or valve opening.

Weekly

6. Turn the motor: Turn off the power and manually turn the coupling 2–3 turns until there is no binding.

7. Tighten the bolts: Retighten the base, flange, and motor terminals diagonally.

8. Clean the filter: Disassemble and clean the suction filter to remove all coal slime, crystals, and fibers. 9. Add oil/grease: Fill the bearing housing and gearbox oil level to 2/3; for mechanical seals with oil cups, add 2 drops daily.
10. Test insulation: Motor-to-ground ≥0.5 MΩ. If below, dry or repair.
Monthly
11. Change flushing fluid: Refresh the mechanical seal flushing tank (Plan 32/54) every 500 hours or monthly to prevent crystallization and blockage.
12. Calibrate safety valves: Increase pressure to the set value, and ensure smooth opening and closing, without sticking.
13. Check seals: Magnetic pump isolation sleeves, diaphragm pump diaphragms, and screw pump bushings. Replace immediately if cracks ≥1 mm.
14. Clean coolers: If scale thickness >1 mm, circulate 5% citric acid for 2 hours to prevent overheating.
Quarterly
15. Dynamic balancing: Dynamically balance the impeller and rotor, ensuring vibration ≤4.5 mm/s. Any exceeding the standard should be returned to the factory. 16. Material Inspection: PMI testing is performed in a chloride ion environment to confirm that there is no mixing of 316L/2205/C276.
17. Standby Switchover: The primary and secondary pumps are alternately operated for 30 minutes to prevent seizure from prolonged idle time.
Annually
18. Overhaul: Every 4000 hours of operation or once a year, the impeller, sleeve, seal, and bearings are disassembled and inspected. All wearing parts are replaced, and the pump is re-balanced and subjected to a hydrostatic test.