Abstract: This invention is an improved vent for a roofing system comprising: a flange having spacers defining an air channel between the roof system and the flange; a flange opening in fluid communication with the roofing system; a tube carried by the flange; a lower valve disposed in a fluid flow path between the roof system and the tube; an external extension assembly extending outward from the tube; a distal opening included in the external extension assembly configured to draw fluid from the roof system through the tube out the distal opening due to an efflux of external fluid across the distal opening; and, a check valve in fluid communications with the external extension assembly, wherein the check valve and the lower valve open when fluid is drawn from the roof system through the tube and out the distal opening.

Abstract: A housing for a ventilation arrangement, with a profiled rod providing a radial extension in each corner, with a pivotted guide vane extending between the rod and the remainder of the housing. In normal wind conditions this radial extension guides air into or out of the housing. In very high wind conditions the guide vane can however pivot and/or flex to release any excessive pressure caused by the high wind.

Abstract: A set of methods and apparatus for efficiently pressurizing and ventilating an air-supported greenhouse or other structure requiring pressurization and ventilation. A method for efficiently pressurizing and ventilating an air-supported structure comprises directing any external wind flow and external wind pressure into mechanical flow means, such as a fan, or fans in parallel, operating in the intake direction, and into the internal space of the air-supported structure and out of the internal space of the air-supported structure through internal pressure regulating exhaust means, whereby the internal space of the structure will be ventilated and pressurized with the assistance of any external wind and the reliability of mechanical flow means (fans).

Abstract: A damper for allowing some degree of air flow (winter ventilation) through a roof mounted, conduit to aid in preventing the growth of black mold in an attic while aiding in heat retention during colder periods of the year. The low profile damper is comprised of a housing having a plurality of louvers pivotably mounted therein. A linkage strip interconnects the louvers together whereby a bimetal coil move the louvers in unison between their open and closed positions in response to temperature. The damper includes an air flow selector means that allows a “selected” closed position to be selected at which a predetermine volume of air is allowed to flow through the damper.

Abstract: A method and apparatus adjusts an opening in the flow of exhaust to ensure a constant velocity of the exhaust.