earticle

영어

The experimental results 01' the 2 stage Gifford-McMahon(GM) type pulse tube refrigerator (PTR) for cryopump are presented in this paper. The objectives of this study are to develop design technology of the integral type 2 stage PTR which rotary valve is directly connected to the hot end of the regenerator and acquire its improved performance. Design of the 2 stage PTR is conducted by FZKPTR(forschungs Zentrum Karlsruhe Pulse Tube Refrigerator) program for the design of pulse tube refrigerators. The fabricated PTR has U-type configuration and incorporates orifice valve, double-inlet valve and reservoir as phase control mechanism. Rotary valve is used to make pulsating pressure and is directly connected to inlet of lst stage regenerator. From experiments, cooling performance map and pressure waveform at each point were measured for different operating frequencies. Experimental results show the best cooling performance with 2 Hz operation in spite of small pressure amplitude. The lowest temperatures of the 2
stage PTR were 16.9 K at the second stage and 58.0 K at the first stage. The cooling capacities achieved were 14.4 W at 79 K, the first stage and 3.6 W at 29 K, the second stage.