Cryogenic Liquid Cylinder Development

Abstract

The evolution of liquid cylinders has resulted in the present, durable, long lasting tough design. All cylinders are built to the DOT-4L code, with exacting specifications for materials, pressure, and capacities. They use superinsulation (a combination of aluminum foil and fiberglass paper) which will not support combustion.

The modern vessel configuration, (Figure 1) used with gas and liquids, has a complex construction consisting of: pressure building coil, pressure building regulator, vaporizer, pressure building valve, economizer regulator, liquid valve, vent valve, gas use valve, pressure gauge, relief valve, and rupture disk.

Non-Code design considerations include minimizing heat loss by minimizing radiation, conduction, and convection heat losses and constructing a neck tube strong enough to support the tank. Overriding all other concerns is that the tank must be designed to take abuse.

The cryogenic container design has development through three generations. As they evolved, these tanks have incorporated more and more elements that provided for safety and ruggedness. Examples of tanks from various major manufacturers and how they developed over the years are presented.