Clean room head assembly

Claim 1

In a vertical-flow air diffuser plenum assembly having: a generally rectangular hood formed of a unitary piece of sheet material in a generally pyramidal rectangular shape and including an air supply opening at an apex thereof and an open bottom; means for connecting a source of air supply to said air supply opening in said hood; a deflector mounted in said hood beneath said air supply opening to at least partially deflect air entering said hood through said air supply opening in a lateral direction along the inside surface of said hood; a rectangular filter medium; means for mounting said rectangular filter medium beneath the said open bottom of said hood and in generally air-flow relationship therewith so that air entering said air supply opening passes through said filter medium; the improvement in said hood which comprises: the hood apex is formed by a substantially horizontal wall; and a plurality of smooth continuous horizontal, generally rectangular ridges extending 360 degrees around said hood between said apex and said bottom opening thereof, said ridges being spaced between the apex and bottom of said hood and shaped so as to deflect air flowing along said hood inside surface downwardly through said filter medium in a substantially uniform flow pattern thereacross.