A refrigerated transport Dewar is a

refrigerated The term refrigeration refers to the process of removing heat from an enclosed space or substance for the purpose of lowering the temperature.International Dictionary of Refrigeration, http://dictionary.iifiir.org/search.phpASHRAE Terminology, ht ...

transport vessel with an insulated Dewar flask ( vacuum) design to carry

cryogenic In physics, cryogenics is the production and behaviour of materials at very low temperatures. The 13th IIR International Congress of Refrigeration (held in Washington DC in 1971) endorsed a universal definition of “cryogenics” and “cr ...

liquid A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. As such, it is one of the four fundamental states of matter (the others being solid, gas, a ...

. To prevent pressure build-up they are equipped with safety relief valves and/or

rupture disc A rupture disk, also known as a pressure safety disc, burst disc, bursting disc, or burst diaphragm, is a non-reclosing pressure relief safety device that, in most uses, protects a pressure vessel, equipment or system from overpressurization ...

s. The liquid can be withdrawn as a gas by passing liquid through an internal vaporizer or as a liquid under its own vapour pressure.

History

A non refrigerated air-transportable dewar for 750 liters of liquid hydrogen was developed by H.L. Johnston in ca. 1952.LIQUID HYDROGEN AS A PROPULSION FUEL,1945-1959
/ref> The heat flow to the liquid hydrogen shell was 4 watts, boil-off about 7.5 liters per day, or 1% of the rated capacity. They were equipped with valves,

instruments Instrument may refer to: Science and technology * Flight instruments, the devices used to measure the speed, altitude, and pertinent flight angles of various kinds of aircraft * Laboratory equipment, the measuring tools used in a scientific lab ...

, and a vacuum pump. The refrigerated transport dewar was based on a design by the Arthur D. Little Company and produced by the Cambridge Corporation using a closed cycle helium refrigerator, the 2000 liters of liquid hydrogen could be stored or transported indefinitely with no loss as long as the refrigerator was operated. It was placed on a 10.7-meter semi-trailer and weighed 18.1 metric tons, including a diesel generator for refrigerator operation away from electric power lines.

References

{{HydrogenDelivery Hydrogen infrastructure

History

See also

References