During the operation of industrial vacuum equipment, many enterprises encounter issues where a vacuum pump fails to generate a vacuum or cannot reach its rated ultimate vacuum level. Substandard vacuum levels directly affect production processes and reduce product yield. To help users quickly troubleshoot and perform basic repairs, this article outlines ten common causes of insufficient vacuum levels, along with targeted solutions that are both practical and easy to understand.
1. Leaks in the intake piping or connection points: Pipeline leaks are the primary reason for failing to achieve the desired vacuum level; external air continuously seeps in, preventing the vacuum from reaching the target depth. Carefully inspect the piping for leaks and address them precisely. In an emergency, vacuum-grade sealing putty can be used to temporarily plug the leak.
2. High temperature of the pumped gas: If high-temperature gas enters the pump chamber, the internal saturated vapor pressure increases, which diminishes the pump's suction capacity. It is recommended to install a cooling device on the intake line to lower the gas temperature and ensure stable pumping efficiency.
3. Insufficient oil level or incorrect oil type: An inadequate amount of vacuum pump oil or the use of the wrong type of oil can compromise sealing and lubrication. Ensure the oil is topped up using the correct, specified grade of vacuum pump oil; never substitute it with standard mechanical oil.
4. Deterioration or contamination of vacuum pump oil: Over time, oil can become contaminated with moisture, dust, or other impurities, leading to cloudiness, emulsification, or carbonization—all of which significantly degrade sealing performance. It is recommended to drain the old oil completely and replace it with fresh, original-manufacturer-specified vacuum pump oil.
5. Low oil temperature due to a cold environment: In cold environments—such as workshops during winter—the oil may become overly viscous and lose its fluidity, which can temporarily impair the vacuum pump's performance. Allow the equipment to run unloaded for half an hour to warm up; once the oil temperature has risen, normal vacuum performance should be restored.
6. Damaged or leaking exhaust valve plates: Exhaust valve plates that have aged or cracked can cause gas backflow, preventing the vacuum from being maintained. The pump housing must be disassembled to replace the exhaust valve plates, thereby restoring the one-way sealing function of the exhaust system.
7. Damaged rubber sealing gaskets in the piping: Rubber gaskets at intake ports or flanges may age, harden, or deform over time, creating gaps that lead to leaks. Simply replace these gaskets with new ones to restore the integrity of the seals.
8. Presence of condensable vapors in the gas: Water vapor or organic solvent vapors entering the pump can cause the oil to emulsify and limit the achievable vacuum. Consider installing a gas ballast valve or a vapor trap to filter and condense these vapors before they enter the pump.
9. Excessive internal clearances due to component wear: Long-term operation can cause wear on the rotary vanes, rotor, and pump chamber, leading to larger internal clearances and reduced compression efficiency. The unit should be disassembled for inspection; worn components must be replaced, and internal clearances must be recalibrated during reassembly.
10. Incorrect selection of vacuum measurement instruments: Using the wrong type of instrument can result in inaccurate readings. Industry standards recommend using a compression vacuum gauge (based on partial pressure) for assessment; alternatively, an electronic vacuum gauge can be used in conjunction to evaluate the true vacuum level based on total pressure.
