Abstract: An air diffuser includes a mask plate spaced upstream from an orifice plate in a generally parallel relationship. The orifice plate includes openings in a first zone arranged in a non-linear pattern, inside a second zone arranged in a linear pattern. Both zones can be within a peripheral wall defining the spacing between the mask plate and the orifice plate. The mask plate has a large opening for air, with a footprint slightly larger than the first zone. The density and zone arrangement of the mask plate and the orifice plate results in a better umbrella pattern flow of air exiting the diffuser.

Abstract: An air diffuser includes a mask plate spaced upstream from an orifice plate in a generally parallel relationship. The orifice plate includes openings in a first zone arranged in a non-linear pattern, inside a second zone arranged in a linear pattern. Both zones can be within a peripheral wall defining the spacing between the mask plate and the orifice plate. The mask plate has a large opening for air, with a footprint slightly larger than the first zone. The density and zone arrangement of the mask plate and the orifice plate results in a better umbrella pattern flow of air exiting the diffuser.

Abstract: A sliding plate air damper allows control over air flow with the sliding plate having a range of positions which do not change the total area of the orifices through the damper. Openings through the fixed plate and the openings through the sliding plate can each make up about 70% of the active area of each plate. The slide plate can be slid to a position where its webbings divide each fixed plate opening into two orifices for air flow. The air flow can be controlled by selecting the slide position of the webbings from a most restrictive position in which the webbings are in the middle of fixed plate openings, through a range of positions where the orifice on one side of the webbing is larger than the orifice on the other side of the webbing, to a maximally opened position where the webbing on the slide plate overlies the webbing on the fixed plate.

Abstract: A sliding plate air damper allows control over air flow with the sliding plate having a range of positions which do not change the total area of the orifices through the damper. Openings through the fixed plate and the openings through the sliding plate can each make up about 70% of the active area of each plate. The slide plate can be slid to a position where its webbings divide each fixed plate opening into two orifices for air flow. The air flow can be controlled by selecting the slide position of the webbings from a most restrictive position in which the webbings are in the middle of fixed plate openings, through a range of positions where the orifice on one side of the webbing is larger than the orifice on the other side of the webbing, to a maximally opened position where the webbing on the slide plate overlies the webbing on the fixed plate.