Enclosure for maintaining a controlled atmosphere around a work station

摘要

An enclosure enveloping a work area with a controlled gaseous atmosphere. It is particularly useful as a welding enclosure for welding metals in a total atmosphere of inert gas. The enclosure consists of a basal portion which rests on a table or work bench of similar dimensions and geometry. A short lower portion is preferably of somewhat smaller horizontal cross section than an attached much larger upper portion. A gas diffusion ring is located inside about midway between the top and bottom. There is a recloseable gas tight opening in or adjacent the top for introducing workpieces and a one way vent valve at or adjacent the highest point on the top. When ready for introducing the workpiece the hood drapes neatly and uniformly around the workbench and the gas diffusion ring is enclosed at the lowest part of the draped portion. Argon is the inert gas of preference. When it is introduced it displaces any remaining air ahead of it and ultimately out the vent valve. Because of its construction the hood may be purged of any remaining air and ready for use within minutes with a minimum waste of inert gas.