Suction Performance Degradation of Liquid Ring Vacuum Pumps due to Non-condensable Gas Degassing under Low Temperature and High Vacuum Conditions

This study investigates the causes of suction performance degradation in a liquid ring vacuum pump under low temperature and high vacuum conditions. The internal gas behavior was analyzed in response to changes in seal water temperature. The results demonstrate that in high vacuum regions below 1.0 inHga, suction performance decreases despite lower temperature due to the degassing of dissolved gases. This internal gas load effect was dominant particularly under low flow conditions, as evidenced by changes in dissolved oxygen(DO) levels. These findings indicate that internal degassing, alongside vapor pressure, is a critical factor in determining pump performance during high vacuum operation.