Abstract: An air outlet through which air is supplied to the room of a building or the like which includes a plurality of blower elements arranged in at least one row, with each element being independently angularly adjustable to supply air within a range of definite blast directions. The length of each individual blower element is maximally approximately 12-25 times greater than the thickness of the outwardly flowing stream of supply air.

Abstract: In a filter box a first air flow generating unit drives air, containing solid impurities, through a filter disposed upstream of said unit. Without interrupting the drawing of impure air into the filter box, the filter is periodically cleaned by drawing auxiliary air through the clean side of the filter by a second air flow generating unit for dislodging and carrying away impurities accumulated on the work side of the filter. The drawing of impure air into the filter box is effected by the second air flow generating unit during the periodic cleaning operation.