Stainless steel is a reasonable and cost-effective metal that provides a good degree of catalytic ability. In fancy talk that means that it lowers the activation energy for a chemical process to take place which, in this case, is dissolved air coming out of the water (AKA coming out of solution), like carbon dioxide bubbles come out of pop (but for a different reason) once opened.
There are other metals that provide more significant catalytic properties, such as platinum which is used in a car’s catalytic converter for example. But these other alloys / exotic metals cost significantly more and are often costlier to work with.
In this sense, typical stainless steels of 304 & 316 provide a good cost balance between performance, durability, and cost. Stainless steel provides a better catalytic ability than carbon steel and copper, and has the advantage of being more resistance to rust or other oxidation on its surface. Carbon steel rusts making its surface not effective and copper develops a green oxidation film on it further reducing its ability to provide catalytic ability.
If you have ever put your tongue on stainless steel, it produces a very small tingle effect, that is a very, very small electrical current that gets generated on the surface of the metal in question. It is this ability of stainless steels and other similar metals to provide a very electrical current on their surface that helps to draw the dissolved oxygen out of solution (water).
The Aar-O-Vent®, in ADDITION to the catalytic property of stainless steel, ALSO draws the air out of solution by creating low-pressure areas/volumes. In these low-pressure regions, the dissolved air has an AFFINITY to come out of solution.
So, for the Aar-O-Vent®, you have two driving forces to bring the air out of solution:
a) catalytic surface of the stainless steel (this is a chemical effect)
b) the geometry of the unit (this creates low-pressure regions)
Independent Lab Test Results
Dirt Elimination Air Elimination