The Dri-Tech chamber comes pre-assembled, and it is only necessary to fill with a charge of desiccant medium. Granular Drierite™ is convenient because it has a built-in moisture-content indicator (blue to pink when saturated), but other media can be used (e.g. molecular sieve).
To fill, unlatch the lid and pour in sufficient desiccant medium to completely cover the Nafion tubing. This typically requires about ½ pound (455g) of medium. Be careful to remove any granules that may be on the rubber seal around the lid that might otherwise prevent the airtight seal.
When not in use, insert the tethered Luer plugs into the chamber connectors to prevent humid air from entering the tubing.
The Dri-Tech Desiccant Chamber system is used to remove water vapor from gas being measured with gas analyzers (MM-100 metabolic monitor, GEMINI O2 & CO2 monitor, Capstar-100 and Oxystar). It works by passing the gas sample through a Nafion™ membrane tubing contained in a sealed chamber filled with desiccant medium. The Nafion™ membrane selectively passes water molecules across a humidity gradient. The air in the chamber is extremely dry because of the desiccant, so water vapor is removed from the gas through a process of equilibration. The Dri-Tech desiccant/membrane system has the advantage of being low dead-space, so it does not contribute to sluggish analyzer response as occurs with a traditional desiccant-filled in-line tube. Maintenance is easy: simply replace the desiccant medium (indicating Drierite™ is supplied) when it becomes saturated.