Studies on the purification of helium gas using a vortex tube

摘要

The paper describes a novel application of a vortex tube for purification of helium gas. Experiments have been conducted using helium-oxygen mixtures of 8.5% oxygen impurity. The gas mixture at an optimum vortex inlet pressure of 0.7 MPa is cooled down by the enthalpy of evaporating liquid nitrogen and the cold end output of the vortex tube. Significant phase separation is achieved below a vortex inlet temperature of 92 K. The liquid phase thrown out through the conventional hot end adjusted to optimum throttle valve opening is nearly 100% oxygen. During a single pass of the mixture, the oxygen impurity could be reduced by 2% from the original value. This indicates the possibility of achieving lower impurity levels of helium gas by recirculating the gas-mixture through the system.