Air diffusers for use with light troffers

Claim 1

AN AIR DIFFUSER COMPRISING WALL MEANS DEFINING A NARROW, REGULAR TRAPEZOIDAL AIR PASSAGE, SAID WALL MEANS INCLUDING CLOSELY SPACED OPPOSED, REGULAR TRAPEZOIDAL SIDE WALLS DEFINING THE SIDES OF SAID TRAPEZOIDAL AIR PASSAGE AND SLOPING END WALLS JOINING THE SLOPING EDGES OF SAID TRAPEZOIDAL WALLS, AN ELONGATED NARROW FLANGE LONG THE LONGEST EDGE OF ONE OF SAID SIDE WALLS AND EXTENDING TOWARD BUT TERMINATING SHORT OF THE CORRESPONDING LONGEST EDGE OF THE OTHER OF SAID SIDE WALLS AND DEFINING THE SPACE THEREBETWEEN A LONG, NARROW, DOWNSTREAM, AIR DISCHARGE SLOT IN THE BASE OF SAID TRAPEZOIDAL PASSAGE, PASSAGE MEANS FOR SUPPLYING AIR TO THE UPSTREAM PORTION OF SAID TRAPEZOIDAL PASSAGE, ELONGATED, AIR-DIRECTING MEANS IN SAID TRAPEZOIDAL AIR PASSAGE ADAPTED TO DIRECT THE AIR STREAM FLOWING THERETHROUGH TOWARD THE UPSTREAM SIDE OF SAID FLANGE SUBSTANTIALLY ALONG THE ENTIRE LENGTH THEREOF MEANS PIVOTALLY MOUNTING SAID AIR-DIRECTING MEANS ON THE OTHER SIDE WALL, AND SAID TRAPEZOIDAL SIDE WALLS CONVERGING TOWARD EACH OTHER FROM SAID PASSAGE MEANS IN THE DOWNSTREAM DIRECTION TOWARD SAID SLOT.