Mark W Dittmer
Architects at Cypress St, Aullville, MO

4498373, Feb 12, 1985

Apr 18, 1983

6/485746

Willard W. Dittmer - Higginsville MO
Mark W. Dittmer - Higginsville MO

F24F 7007

98 331

In negative pressure ventilating system wherein atmospheric air is introduced along the walls of a building adjacent the roof, insulated, hinged valves provided within the associated airways rise automatically from their lower, fully closed position by the pressure of the incoming air as the inside pressure is reduced to below atmospheric. The bottoms of the valves and the surfaces upon which they rest, when closed by gravity, are contoured to reduce resistance to free air flow in the airways. A smooth, uninterrupted change of directional flow is effected by streamlining both the valves and the opposed surfaces, virtually eliminating air turbulence from the inlets to the discharge ends of the air ducts. By elimination of abrupt changes in the direction of flow the incoming air is properly controlled. The air is gradually directed along the airways downwardly and inwardly away from the ceiling and the adjacent wall such as to provide proper air distribution within the building regardless of variances in the rate of air flow.