Phase shifters in a high frequency pulse tube cryocooler

The double-inlet and inertance tube as phase shifters; used in a high frequency miniature pulse tube cryocooler (PTC) are experimental investigated. For the double-inlet PTC, the optimum adjusting method of the orifice and secondary bypass is different from the traditional method. The experimental results show that the lowest temperature obtained by the optimum adjusting method is 1.5-5K lower than that by the traditional method at different charge pressures and operating frequencies. As phase shifters used in high frequency miniature PTC, inertance tubes can cause impedance unmatching phenomenon. When the phase angle that the pressure leads the volume velocity at the hot end of the PTC is large, the impedance at the hot end is small.