A Transfer Line for Liquefied Gases

A transfer line is a pipeline used to convey very cold fluids from one place to another. The transfer line described in this paper was specially designed for use with liquid hydrogen but could easily be used to transfer other cold fluids such as liquid nitrogen, air or helium. It is installed in the NBS-AEC Cryogenic Engineering Laboratory’s liquid hydrogen plant to transfer liquid hydrogen from the liquefiers to the storage and transport dewars. Special emphasis is placed on features which contribute to lower heat leak, simplicity and reliability. The primary design consideration is to reduce heat transfer from the warm ambient atmosphere to the liquid. In our application, high vacuum is used as the insulation in the annulus between the two concentric tubes with the cold fluid flowing through the center tube.