Maintenance Methods and Key Points for Coating Equipment Gear Metering Pumps

In industrial coating production, Coating Equipment Gear Metering Pumps play a vital role with their precise metering and stable delivery capabilities. However, even the most sophisticated and durable equipment cannot operate without scientific and standardized maintenance. Proper maintenance not only effectively extends the service life of the pump and reduces failure rates, but also ensures production continuity and the stability of product coating quality. The following systematically elaborates on the maintenance methods and core key points of Coating Equipment Gear Metering Pumps.

I. Preventive Maintenance During Daily Operation

Prevention is better than cure, and good daily operating habits are the first line of defense for maintenance.

1.  Pre-start Inspection: Conduct a brief inspection before each start-up. Confirm that the inlet and outlet pipeline valves are in the correct open/closed position, check whether all connection parts are tight, and look for signs of leakage. For newly installed pumps or those out of service for a long time, manually turn the pump shaft to check if rotation is smooth and free of jamming.

2.  Standardized Start-stop Operations: Before starting, ensure the pump cavity is fully filled with medium to avoid dry running. For high-viscosity coatings, preheat the pump body if necessary to reduce start-up load. Follow the principle of “start at low speed and accelerate gradually” during start-up. When shutting down, especially after transferring quick-drying or high-viscosity media, perform thorough cleaning immediately to prevent residual materials from solidifying inside the pump, which may cause gear seizure or damage.

3.  In-operation Monitoring: During pump operation, operators should monitor the equipment through listening, touching and observing. Listen for steady running sounds and check for abnormal impact or friction noise; touch the pump body to feel if the temperature rise is within the normal range (usually not exceeding 60–70℃); observe if the pressure gauge reading is stable and check for leakage at the sealing parts.

II. Regular Scheduled Maintenance

In addition to daily maintenance, formulating and implementing a strict regular maintenance plan is the key to ensuring the long-term stable operation of the equipment.

1.  Cleaning and Sanitization: This is the most frequent and important part of maintenance work. Select appropriate cleaning agents (such as solvents or special cleaning fluids) according to the properties of the transferred coating, and ensure all residues inside and outside the pump — especially in gear meshing areas and small flow channels — are completely removed. Avoid using hard objects like metal brushes to scrape precision mating surfaces during cleaning.

2.  Seal System Inspection and Replacement: Shaft seals (whether mechanical seals or magnetic seals) are one of the vulnerable parts of the pump. Regularly check the wear condition of the sealing components. For mechanical seals, if leakage exceeds the standard or the seal faces are severely worn, replace them in pairs. For magnetic seals, check the magnetic strength of the magnetic driver and whether the isolation sleeve has signs of wear or damage. Only use original factory or specified accessories for seal replacement, and ensure the installation direction and accuracy meet requirements.

3.  Clearance Inspection Between Gears and Pump Cavity: After long-term operation, wear will cause increased clearances between gear end faces and side plates, as well as between gear addendum circles and the pump body. This directly leads to increased internal leakage, reduced volumetric efficiency and decreased output flow of the pump. During major overhauls, use feeler gauges and other tools to accurately measure these key clearances. When the clearance value exceeds the maximum allowable limit specified by the manufacturer, consider replacing vulnerable parts such as gears or side plates to restore the pump’s original performance.

4.  Bearing Inspection and Lubrication: Check if the bearings supporting the gear shafts rotate smoothly and are free of looseness or abnormal noise. For bearings requiring external grease lubrication, regularly replenish the specified grade of grease in the correct amount. Avoid over-lubrication or under-lubrication, and prevent grease from contaminating the transferred medium.

III. Quick Diagnosis and Handling of Common Faults

l Insufficient Flow or Unstable Pressure: The primary cause is excessive clearance due to internal wear — inspect the gears and side plates. Secondary causes may include clogged inlet filters or air leakage in the suction pipeline — inspect and clean the filter, and tighten the connectors.

l Abnormal Noise or Vibration: Possible causes include air ingress into the pump (cavitation), medium viscosity far exceeding the pump’s design range, bearing damage, or solid impurities jamming the gear meshing faces. Troubleshoot air ingress points one by one, verify medium parameters, inspect bearings and clean the pump cavity.

l Leakage at Seals: For mechanical seals, leakage is mostly caused by end-of-life normal wear or seal face damage. For packing seals, it may be due to loose gland covers or worn packing. Stop the pump and replace the corresponding sealing components.

Summary

Systematic maintenance of Coating Equipment Gear Metering Pumps is a high-return investment. It requires users to establish a full-process management awareness covering daily operations and regular maintenance. With careful care, this “heart” of the coating system will surely provide long-lasting and strong power support for your stable production and superior product quality, with a longer service life, higher operational efficiency and lower failure rate.