Description

Gastec P-3 Permeation Tube Ammonia generating calibration gas with a permeation tube.

A permeation tube is a fluoro resin tube that contains high-grade liquefied gas. When the tube is exposed to a certain temperature, liquefied gas penetrates the tube wall by osmosis in time-increments enabling a specific quantity of gas to be retained in the tube.

Consequently, a carrier gas flowing at a constant speed (for calibration purposes) can be continuously generated by keeping the tube at a fixed temperature and infusing a constant quantity of dilution gas.

This method is highly reliable because the concentration of the calibration gas is determined by calculating the decrease in weight of the permeation tube and the quantity of dilution gas. This dynamic method also enables highly reactive gases such as chlorine, hydrogen sulfide or ammonia to be generated.