Scroll pump (scroll compressor) is an oil-free vacuum pump used for obtaining #prevacuum with a level of 0.1 mbar. The #scrollpump is based on two scrolls, that are placed insede the working chamber. One of these scrolls is fixed and the other one mobile. Once the gas enters the system through the inlet, it gets carried to the outlet in the middle by the mobile orbiting scroll. This is possible due to the fact that during the mobile scrolls movement a wide gap is locally kept between the two scrolls and the gap moves to the middle, carrying the gas in it. As the volume of the gap decreases at the outlet, the gas is pushed out of the system. Due to wear the orbiting scroll needs to be replaced about twice a year.