Nafion tubing is a highly selective, semi-permeable membrane to water vapor. If gases inside Nafion tubing are wetter than gases surrounding the tubing, drying will occur. If the surrounding gases are wetter, humidification will occur. In normal use, a portion of Nafion tubing is used as a portion of the tube between a gas sample stream and a sensor. If the sample stream is much wetter than ambient air (such as breath samples), the sample falls to ambient humidity. If the sample stream inside is much drier than ambient air (such as calibration cylinder gases), the sample rises to ambient humidity.
Because Nafion uses sulfur ions to selectively transport water molecules out of the tubing, it is not gas permeable. Therefore, Nafion can be used successfully to dry virtually any gas. Naphion is also recommended to be used with water traps & hydrophobic filters that are included with all sampling devices. Install the tubing after the filters for optimum performance & protection of the sensor.
Caution: While Nafion can remove virtually any humidity from a gas sample, filling it with liquid water will result in the loss of the ability to remove water vapor. Normally, drying the tubing completely will restore functionality.
Read about Nafion tubing from the manufacturer’s website.