The Permeation Loop consists of permeation membrane tubing encapsulated in a trap-heated glass tube. When sample liquid is pumped through the permeation tubing, the dissolved gases therein selectively permeate through the heated membrane into the surrounding extraction chamber, which is plumbed as the loop of a 10-port gas sampling valve.
The Permeation Loop Accessory includes the permeation trap, two peristaltic pumps, two solenoid valves and a standards preparation sparge head. By reconnecting a few tubing lines, the DGA Permeation Loop Accessory can be configured to prepare dissolved gas standards. A Tedlar bag, or other container, filled with gas standard is connected to the standard pump. The standards preparation vessel is filled with sample liquid, such as water or transformer oil. The standard pump bubbles gas standard into the standards preparation vessel, equilibrating the liquid over time to a known concentration.