High viscosity liquid transfer pumps are key equipment in industries such as chemical, petroleum, food, and coatings, and their stable operation directly affects production efficiency and product quality. Due to the viscosity, easy solidification or corrosiveness of the conveying medium, standardized daily cleaning, regular maintenance and timely replacement of vulnerable parts are the cornerstone to ensure its long service life and high efficiency performance. This article will systematically provide you with a set of practical operation and maintenance suggestions.
1、 Daily cleaning: eliminate residues and prevent problems before they occur
Daily cleaning is the primary step in preventing the solidification, crystallization, or cross contamination of the medium inside the pump, and should be strictly followed every time the machine is stopped or the conveying medium is replaced.
1. Rinse principle: Follow the principle of "empty first, rinse later". After shutdown, first open the outlet pipeline and try to drain the residual medium in the pump chamber and pipeline as much as possible. For easily curable media, this step needs to be completed quickly.
2. Selection of cleaning agents:
Universal type: For most media, use a solvent compatible with the next production material (such as warm water, hot water, alcohol, diluent, etc.) for cyclic flushing.
Specialized type: For stubborn residues such as paint and resin, specialized cleaning agents or high-temperature steam should be used. Be sure to refer to the Material Safety Data Sheet (MSDS) to select appropriate and safe cleaning agents.
3. Cleaning process:
Forward and backward flushing: Inject cleaning agent into the inlet of the pump and discharge it from the outlet for forward circulation flushing. For stubborn blockages, the "backwash" method can be used, which involves injecting cleaning agent from the outlet and discharging it from the inlet to flush out dead corners.
Circulation and soaking: Let the cleaning agent circulate in the pump and pipeline system for 10-15 minutes. For severe scaling, the outlet valve can be closed and the cleaning agent can be soaked in the pump chamber for a period of time to soften the residue before circulation.
Blow drying: After cleaning, use dry and clean compressed air to blow the pump chamber and pipelines, remove residual cleaning agents and moisture, and prevent rust or reaction with the next conveying medium.
2、 Regular maintenance: System inspection to maintain optimal condition
In addition to daily cleaning, regular systematic maintenance can effectively detect and eliminate potential faults.
1. Daily/weekly check:
Running status: Listen to the pump for any abnormal noise or vibration during operation.
Sealing performance: Check for signs of leakage in the mechanical seal or packing box. For single end mechanical seals, slight leakage may be due to normal lubrication and cooling, but the formation of dripping should be cautious.
Temperature rise: Touch the pump body to check for overheating. High temperatures may be caused by poor lubrication, component wear, or motor failure.
2. Monthly/Quarterly Maintenance:
Tightening and lubrication: Check and tighten the anchor bolts and pipeline connections. According to the manufacturer's requirements, add or replace lubricating grease (oil) to the bearing housing to ensure good lubrication of the bearings.
Motor maintenance: Check if the motor current is within the rated range, clean the dust on the motor cooling fan and housing.
Safety valve/relief valve: Check if the safety valve is functioning properly and ensure that it can reliably open at the set pressure.
3、 Suggested replacement cycle for vulnerable parts: key to predictive maintenance
The lifespan of vulnerable parts is affected by various factors such as medium characteristics, working pressure, and operating time. The following is a general recommended cycle, and actual replacement needs to be adjusted according to specific working conditions.
1. Seals (mechanical seals/packing seals):
Suggested cycle: 3-12 months. This is one of the most critical vulnerable parts.
Signal replacement: Continuous leakage, significant decrease in pump efficiency, or increased noise during operation. For the transportation of highly corrosive or particulate media, the cycle should be shortened. It is recommended to keep a set of spare seals on hand for emergency use.
2. Rotor and stator (core components of screw pump):
Suggested cycle: 6-18 months. The clearance between the rotor and stator is the key to ensuring the self-priming capacity and flow rate of the pump.
Signal replacement: significant decrease in flow rate, unstable pressure, loss of self-priming ability, or abnormal increase in operating current. When wear causes excessive clearance, the rotor and stator must be replaced in pairs.
3. Valve group and sealing ring (gear pump, plunger pump, etc.):
Safety valve/relief valve: Check its performance 12-24 months or after each system pressure calibration.
Import and export valve discs/ball valves: 6-12 months, check for wear and sealing.
O-ring/gasket: Replace it together with each major overhaul or replacement of core components, and it is not recommended to reuse it.
4. Bearings:
Suggested cycle: 12-24 months.
Signal replacement: Abnormal temperature rise, increased operating noise or vibration in the bearing area. Good lubrication is a way to extend the life of bearings.