ICEC/ICMC 2014 Conference

Small scale helium liquefaction system using a two stage GM cryocooler

Not scheduled

1h 45m

Poster presentation (105min)

Speaker

Prof. Srinivasan Kasthurirengan (CCT, Indian institute of Science, Bangalore 560012, India.)

Description

`enter code here`There are a number of applications which require liquid helium for its functioning and some of them are MRI systems, NMR, SQUIDs and other R&D works at cryogenic temperatures. However, in most cases, the above requirement of helium is to be met from liquefaction systems which are quite big, which require considerable efforts to operate and maintain them. Compact small scale liquefaction systems serve quite useful in such cases and such systems have been developed based on two stage Cryocoolers such as GM, Pulse Tube and JT systems. The above systems also turn out to be quite useful for recondensation of helium gas evaporating from cryostats of MRI, NMR, SQUIDs etc. We present here the development of a small scale helium liquefaction system using a commercial two stage GM Cryocooler, which delivers a cooling power of ~ 1.5W @ 4.2 K in its second stage cold head, along with a cooling power of ~ 30 W @ 35K in the first stage, to serve as the radiation shield. In this system, a small copper helium pot is mounted on the second stage cold head, into which the helium gas gets liquefied. The incoming helium gas is initially precooled by the heat exchanger mounted on the first stage. Subsequently, it is cooled in a specially designed heat exchanger mounted on the second stage. This cold helium gas gets liquefied and enters the liquid helium pot. As of now, this liquefaction procedure is a batch process, but can be easily modified for continuous liquid helium production. The paper presents the details of the experimental setup and the preliminary experimental results.