희박기체영역에서의 나선형 홈을 가진 원판형 드래그펌프의 배기속도에 관한 실험적 연구

An Experimental Study on Pumping Speed of Disk-Type Drag Pumps for Spiral Channels in Rarefied Gas Flows

Experimental investigations are performed for the rarefied gas flows in a disk-type drag pump (DTDP). The pump considered in this paper consists of grooved spiral channel on rotors and planar stators. The flow-metre method is adopted to calculate the pumping speed. Compression ratio and pumping speeds for the nitrogen gas are measured under the inlet pressure range of $0.001{\sim}4$ Torr. The maximum of compression ratio was about 3300 for three-stage DTDP, 1000 for two-stage and 100 for single-stage DTDP at zero throughput. The number of stage influences the pumping speed of DPDT