Maintenance and troubleshooting of ceramic vacuum pumps

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Maintenance and Care (I) Maintenance 1. When the pump is stored, the inlet and outlet should be covered with covers. 2. If the pump is not used for an extended period of time, the coupling should be rotated regularly. 3. Pumps that operate 24 hours a day should be stopped every 15 days or so to flush the internal parts of the pump with water. 4. Regularly check (at least once a month) the condition of the seals and gaskets. 5. Replace the grease in the bearing housing after every 2,000 hours of operation. Clean the bearings at least once a year and replace all the lubricating oil; the amount of grease applied should fill 2/3 of the space available, as too much grease is not advisable. 6. After the pump has been in operation for one year, it should be completely disassembled for inspection. Special attention should be paid to the wear at the radial gap between the impeller and the distributor plate; if any abnormal wear is detected, it should be replaced promptly. (II) Installation and Disassembly of the Pump: Users should be aware of the “ceramic” nature of ceramic water ring vacuum pumps; avoid hitting or impacting the pump during disassembly to prevent damage to the ceramic components inside it. Handle the removed parts carefully, and make sure not to damage the roughness of the sealing surfaces. The disassembly of the pump should be carried out in the following order: 1. Disconnect all pipes connected to the pump. 2. Remove the connecting bolts on the coupling, lift the pump off its base, and move it to a suitable location for disassembly. 3. Remove the main shaft coupling on the pump. After completing the above tasks, refer to Figure 2. 4. Remove the bearing end caps at both ends of the pump, then loosen the round nuts that compress the bearings as well as the sleeve nuts at both ends of the shaft. 5. Use bolts to pull out the bearing sleeve on the bearing housing together with the bearing; under no circumstances use a hammer to strike it. 6. Loosen the bolts connecting the bearing housings to the side covers, and remove the two bearing housings at each end. 7. Disassemble the components at the shaft seal area (if performing maintenance or replacing the shaft seal, this is the only step required). 8. Loosen the connecting bolts between the side cover and the pump body. Be careful to loosen them in a diagonal pattern for even tension. Use the removal holes on the side cover to push the side covers away from each other; at this point, use the lifting screws to carefully move the side covers out of place. 9. Loosen the 3 screws on the valve plate, and use the removal holes on the valve plate to detach it. 10. Once the above tasks are completed, the shaft along with the impeller can be removed from the pump body. 11. Loosen the round nut and remove the shaft sleeve; at this point, the impeller can be separated from the shaft. During disassembly, all shims should be removed carefully; those that have become damaged should be replaced with ones of the same thickness and material during reassembly. 12. The assembly sequence of the pump is the reverse of its disassembly sequence. Faults and Solutions
Fault | Cause | Solution
Low vacuum level | Insufficient air supply | 1. Air leakage in the piping system 2. Leakage at the pump shaft seal | 1) Check if the mechanical seal is damaged 2) Blockage in the sealing water pipe or packing ring 3. Overheating of the liquid ring 4. Insufficient water supply 5. Low pump speed 6. The distribution plate is installed incorrectly | 1. Tighten the bolts or replace the gaskets 2) A) Replace the mechanical seal B) Clean the water pipe 3. Lower the water temperature or ambient temperature 4. Increase the water supply 5. If the power voltage is low, increase it 6. Recheck and reinstall the distribution plate
Abnormal noises | 1. Debris inside the pump 2. Broken impeller blades | 1. Stop the pump and remove the debris 2. Replace the impeller
Bearing overheating | 1. Insufficient or excessive lubricant 2. Poor quality of the lubricant 3. Debris inside the bearing 4. Incorrect installation of the bearing | 1. Adjust the amount of lubricant 2. Replace the lubricant 3. Clean the bearing with kerosene 4. Reinstall the bearing
Overheating at the shaft seal | 1. The mechanical seal is too tight | 1. Loosen the mechanical seal slightly
Pump body overheating | 1. Too little water supply 2. Excessively high water temperature 3. Excessively high temperature of the gas being pumped | 1. Increase the water supply 2. Lower the temperature of the water being used 3. Reduce gas humidity
Vibration | 1. Large imbalance in the impeller 2. Excessive misalignment between the pump coupling and the motor coupling 3. Damaged elastic elements in the coupling components 4. Loose foundation bolts 5. Damaged bearings 6. Cavitation | Adjust balance, correct coupling alignment, replace elastic elements, tighten foundation bolts, replace bearings, open the vacuum control valve on the suction pipeline
Difficult starting or high starting current | 1. Mechanical seal too tight 2. Misalignment of the bearings 3. Damaged bearings 4. Rust formation inside the pump after long periods of inactivity | Loosen the mechanical seal slightly, readjust or replace it, replace the bearings, rotate the impeller several times by hand or using special tools