Abstract: A module for providing a work area in which one or several people can perform tasks requiring ultra-high efficiency air filtration. The work area is bounded above by a filter module through which a vertical laminar flow of air occurs from one or more HEPA filters. From the perimeter of the module flows a curtain of air in an enclosing and substantially parallel relationship to the laminar flow air to extend the laminar air zone to the floor. The air curtain also passes through a HEPA filter prior to discharge. The angular direction of the air curtain is adjustably controlled by a unique nozzle structure so that when the air curtain contacts the floor turbulence is substantially eliminated and a sweeping action away from the work area is effected. Separate blower systems supply air for the laminar flow air and the enclosing air curtain at differential velocities.

Abstract: An improved filter holding device for an air filter that forms a chamber around the periphery of the air filter. A vacuum is created within the chamber to carry any unfiltered air to the upstream side of the filter and thus prevent any air from bypassing the filter and contaminating a clean room.