Dry air/gases for analytical instruments

From NMR Wiki

Stream of dry gases (air or nitrogen) are used in the practice of NMR spectroscopy to regulate sample temperature.

Typically gas is cooled to some temperature that is lower then the desired sample temperature. Cooled gas is then passed through electric heater where it reaches the target temperature and then comes in contact with the sample.

Dew point of gas is an important parameter to consider. Dew point should be 20^oC below the lowest temperature anywhere in the path of the gas stream [1].

Contents 1 Dew point sensing 2 Dessicant dryers 3 Pressure Swing Adsorption dryers 4 Membrane dryers 5 Refrigeration dryers 6 Manufacturers 7 References

Dew point sensing

model	range	precision	notes
GE DewPro MMY30	-130oF to 500F (-90 to 10oC)	2oC	has digital display requires recalibration every 6 months for max accuracy, once a year for 5oC accuracy cost ~$2,700

Dessicant dryers

Pressure Swing Adsorption dryers

Hankison, Inc. HHL&HHS Series. Dessicant: activated alumina.

Membrane dryers

Refrigeration dryers

Manufacturers

Hankison, Inc. HHL&HHS Series. Dessicant: activated alumina.

References

1. Instruction manual for FTS XR401 Air-Jet crystal cooler [xr401]