AVS 45th International Symposium
    Vacuum Technology Division Tuesday Sessions
       Session VT-TuM

Paper VT-TuM8
Performance of a Peripheral Drag Pump

Tuesday, November 3, 1998, 10:40 am, Room 329

Session: Molecular Drag Pumping
Presenter: T. Ohbayashi, Osaka Vacuum, Ltd., Japan
Authors: T. Ohbayashi, Osaka Vacuum, Ltd., Japan
T. Sawada, Akita University, Japan
Correspondent: Click to Email
This is a theoretical and experimental study of a peripheral drag pump. It has a peripheral pumping channel and a gas inlet and outlet which are separated by a "stripper", this is similar to a Gaede's drag pump. In that type of pump, a pumping channel comprises an annular groove and a chamber wall. In the pump in this study, two pumping channels which work in parallel comprise a rotating disk and two annular stators. This modification keeps the leak small with a relatively large clearance between the rotor and the stator. The performance of the peripheral drag pump is determined by the flow through the pumping channel, the "carry back", the leak in the "stripper" region, and the leak in the clearance between the rotor and the stator. In the theoretical calculations, the flow through the pumping channel is evaluated as Poiseuille flow and Couette flow through rectangular channels and the flow in the stripper region and in the clearance are evaluated as Poiseuille flow and Couette flow between parallel plates. Experiments were carried out on the peripheral drag pump of a single stage in a pressure range of 3 - 1300 Pa for air and 9 - 1200 Pa for hydrogen. The theoretical predictions agreed with the experimental results.