Glove Boxes: The Effects Of Gas Permeation And Equilibrium

By Bob Applequist, Product Manager, Labconco Corporation

Controlled Atmosphere Glove Boxes are designed to contain an internal inert gas environment, purified to some level. How to achieve the gas purities requires understanding a few fundamental concerns related to the chemistry and physics of gases. Most often misunderstood, and/or overlooked, are the properties of gas permeation and equilibrium. Physics describes permeation as the movement or penetration of gas molecules through a solid substance. All solid materials (glass, plastics and steel) are permeable to some degree. This includes the material used in constructing glove boxes. A simple fact of physics is that a gas at a high concentration within an environment chamber will migrate or permeate through any solid material into another adjacent environment chamber containing a lower concentration of that gas. This is gas permeation which ultimately leads to gas equilibrium.