Closed Loop Delivery System

A closed loop liquid nitrogen piping system was designed specifically for Molecular Beam Epitaxy (MBE) by Vacuum Barrier. The system is fully automated, safe and completely reliable. It consists or vacuum jacketed piping from an outside bulk storage tank to a liquid/vapor phase separator.

Two phase flow of liquid nitrogen enters the phase separator. Gas is vented to the atmosphere, leaving a volume of pure, gas-free liquid nitrogen at -320° F. The liquid is gravity fed to the cryoshroud through a triaxial feed line. The liquid nitrogen is slightly sub-cooled at the lower end of the piping due to the hydrostatic head of liquid. As the liquid enters the cryoshroud and picks up heat the density changes and the lighter liquid nitrogen is returned to the above liquid level in the phase separator. Gas is vented off and the liquid is re-used.