vacuumjacketed

Vacuumjacketed refers to equipment that uses a vacuum as the insulating medium between an inner container and an outer jacket. This double-walled construction minimizes heat transfer from the surroundings to the contents, allowing cryogenic or temperature-controlled fluids to be stored or transported with reduced energy input. The term is commonly used to describe vacuum-jacketed vessels and piping in industrial and laboratory settings.

Construction and principle: A vacuumjacketed vessel consists of an inner vessel that holds the process fluid and an outer shell that provides structural support and protection. The space between the walls is evacuated to a low pressure, creating an insulating annulus. Heat transfer by convection and conduction is greatly reduced in a vacuum; in many designs, multilayer insulation or reflective foils further limit radiant heat transfer. Support structures are designed to be thermally broken to minimize heat paths between the walls.

Applications: Vacuumjacketed equipment is widely used for cryogenic storage and transfer, including dewars for liquids such as nitrogen, oxygen, helium, and argon, as well as liquified natural gas (LNG) systems. Vacuum jacketing is also employed in laboratory cryostats and in long runs of cryogenic piping to keep boil-off rates low and maintain stable temperatures over distance.

Maintenance and considerations: Maintaining vacuum integrity is essential; vacuum loss increases heat gain and boil-off. Periodic checks, vacuum re-evacuation, and leak testing are common. While vacuum jacketing provides superior insulation, it comes with higher manufacturing and maintenance costs compared to simple insulated designs.