Turbo Pumps

LEYBOLD turbomolecular pumps produce a clean high or ultrahigh vacuum. They can be easily operated and provide excellent reliability. Pressures down to 10-10 mbar (0.75 x 10-10 Torr) can be reached in combination with adequately dimensioned roughing pumps.

LEYBOLD is one of the world’s leading manufacturer of turbomolecular pumps. Consequently, the TURBOVAC pumps are successfully used in many applications.

Below are listed the most popular models of Leybold turbo pumps, along with the appropriate frequency converters and cables. Please inquire about additional sizes and configurations.

Principles of Operation

The turbomolecular pump is a bladed turbine that compresses gases. By the momentum transfer from the rapidly rotating rotor blades to the gas molecules the non-directed thermal motion of the molecules is changed to a directed motion. Hence, the pumpingprocess ina turbomolecular pump results from the directed motion of the gas molecules from the inlet flange to the forevacuum port. In the molecular flow range- i.e. at pressures below 10-3 mbar (0.75 x 10-3 Torr) - the mean free path of the gas molecules is larger than the spacing between rotor and stator blades (typically some tenths of a millimeter). Consequently, the molecules collide primarily with the rotor blades with the result that the pumping process is highly efficient. In the laminar flow range- i.e. at pressures higher than 10-1 mbar (0.75 x 10-1 Torr) - the situation is completely different. The action of the rotor is diminished by the frequent collisions between the molecules. Therefore, a turbomolecular pump is not capable of pumping gases against atmospheric pressure and has to be backed by an adequate fore-vacuum pump. To create the directed motion of the gas molecules mentioned above the tips of the rotor blades have to move with supersonic velocity. Hence, a high rotational speed of the rotor is required. In case of LEYBOLD turbomolecular pumps the rotor speeds vary from about 36,000 rpm for large rotor diameters (e.g. TURBOVAC 1000, Å 20 cm (7.87 in.)) to 72,000 rpm for small rotor diameters (e.g. TURBOVAC 50, Å 6 cm (2.36 in.)