Meissner coils come in many shapes and sizes and often are made to fit within a certain space in a vacuum chamber. Between 1x10^-3 Torr to 1x10^-8 Torr the major residual gas in a vacuum chamber is typically water vapor. Meissner coils are an inexpensive method to rapidly remove the water vapor. They can reduce the pump down time as much as 75% eliminating the need for the other expensive vacuum pumps.

Meissner coils consist of a tube which is used to flow a cold liquid or gas and a large surface area. Often the coil is brazed to a shroud or backing plate. Other times fins are attached to the coils.

The lower the temperature the lower the water vapor pressure. For example, to reach a pressure of 1x10^-2 Torr, the average cryo-surface temperature needed is -96°F(-71°C). Whereas, to reach a pressure of 1x10^-7 Torr, an average cryo-surface termperature of -201°F(130°C) is needed.

Technical Data