A turbo molecular pump comprises a pump body having a vacuum chamber, a gas inlet port and a gas outlet port. A rotor shaft is mounted in the pump body for undergoing rotation. A rotor vane section is disposed in the vacuum chamber and has rotor vanes connected to the rotor shaft for rotation therewith....http://www.google.com/patents/US6499973?utm_source=gb-gplus-sharePatent US6499973 - Turbo molecular pump
