Abstract: This invention pertains to a dual seal system for preventing cross-contamination of the bearing compartments from the process cavity, and the process cavity from the bearing compartment, within a Roots blower. The seal system comprises a inner floating seal having a diameter slightly larger than the shaft so that there is a clearance between the shaft and the seal and a face seal embraced at an outer end of the shaft in fixed communication with the shaft and adapted for rotation. A fluid inlet passage is disposed between the floating seal and the face seal, and permits fluid to be introduced to the seals and in the case of the floating seal pass through the clearance space between the floating seal and shaft and then into the Roots blower cavity.