STUDY ON AN INNOVATIVE VIBRATION-CANCELLATION METHOD FOR A PULSE TUBE CRYOCOOLER

研究了一种消除脉冲管制冷机冷段振动的创新方法。采用直径为20mm，长度为200mm的不锈钢细管制作了脉冲管制冷机模型。通过对模型冷冻机冷级振动的测量，验证了该方法的有效性。一个模型制冷机是由在同一冷段上的多对管道组成的。当给定的工作气体向这些对提供适当的相移时，可以消除冷阶段的振动。我们制作了单管、两对管和三对管的脉冲管制冷机模型。与单管模型相比，六管模型在没有额外隔振结构的情况下减少了98%的振动。然后，我们还制作了500张不锈钢网# 100的蓄热器，并将这些部件安装在细管内部，实现了脉冲管制冷机。对具有两组管和蓄热器的自消振脉冲管制冷机进行了制冷功率验证。采用GM型氦气压缩机、数字反相信号产生电路和电磁换向阀，将冷级冷却至最低温度168 K。在这种情况下，模型显示振动减少了约70%。由于该方法中两组脉冲管制冷机的对称性是至关重要的，任何不对称配置都会影响有效减振。

An innovative method for canceling the vibration at the cold stage of a pulse tube cryocooler has been investigated. A thin stainless tube of 20 mm in diameter and 200 mm in length was used to fabricate a model pulse tube cryocooler. The vibration of the cold stage of model cryocooler was measured for proving a method of this innovative vibration cancellation. A model cryocooler consists of multi-pairs of pipes on the same cold stage. When a presented working gas is supplied with a proper phase shift to those pairs, the vibration of the cold stage can be cancelled. We made models of the pulse tube cryocooler with a single pipe, two pairs of pipes and three pairs of pipes. Compared with the single-pipe model, the six-pipe model shows about a 98% reduction of vibration without any additional structure for vibration isolation.Then, we also made the regenerators with 500 sheets of stainless mesh # 100, and set up those components inside of the thin tube to realize the pulse tube cryocooler. The self-vibration canceling pulse tube cryocooler with two set of tube and regenerator was operated to verify cooling power. The cold stage was cooled down to 168 K as the lowest temperature by using a GM type helium compressor, digital circuits for anti-phase signal generation and the solenoid valves for pressure swing. In this condition, the model showed about a 70 % reduction of vibration. As the symmetry of two sets of pulse tube cryocooler is essential in this method, any asymmetric configuration could affect on effective vibration reduction.