The challenge for the vacuum pump is that it must have the ability to handle water vapor and often water droplets. As manufacturers also target the lowest pressures, the pumps are often operated with a closed gas ballast valve which can create water condensation inside the pumps.
Leybold offers several oil-sealed, two-stage TRIVAC rotary vane pumps for this market. However, due to high process robustness, more and more factories equip their production lines with the VARODRY, our air-cooled screw pump. This pump can handle emitted water and achieve low pressures even with closed gas ballasts.