Abstract: A backdraft damper for permitting a flow of air in an outflow direction and preventing the flow of air in a backdraft direction, including a frame having a transverse opening allowing the passage of air through the frame; a plurality of blades, each blade extending across the frame and mounted to the frame about a central portion by pivot members, for rotation between an open position in which the blade allows air to flow through the frame and a closed position in which the blade blocks air from flowing through the frame, the plurality of blades including one or more first blades arranged to rotate in a first direction from the closed position to the open position; one or more second blades arranged to rotate in a second direction opposite to the first direction from the closed position to the open position; the backdraft damper further including a linkage between the one or more first blades and the one or more second blades to cause the first and second blades to together rotate between the closed and open

Abstract: A backdraft damper for permitting a flow of air in an outflow direction and preventing the flow of air in a backdraft direction, including a frame having a transverse opening allowing the passage of air through the frame; a plurality of blades, each blade extending across the frame and mounted to the frame about a central portion by pivot members, for rotation between an open position in which the blade allows air to flow through the frame and a closed position in which the blade blocks air from flowing through the frame, the plurality of blades including one or more first blades arranged to rotate in a first direction from the closed position to the open position; one or more second blades arranged to rotate in a second direction opposite to the first direction from the closed position to the open position; the backdraft damper further including a linkage between the one or more first blades and the one or more second blades to cause the first and second blades to together rotate between the closed and open

Abstract: A backdraft damper for permitting a flow of air in an outflow direction and preventing the flow of air in a backdraft direction, including a frame having a transverse opening allowing the passage of air through the frame; a plurality of blades, each blade extending across the frame and mounted to the frame about a central portion by pivot members, for rotation between an open position in which the blade allows air to flow through the frame and a closed position in which the blade blocks air from flowing through the frame, the plurality of blades including one or more first blades arranged to rotate in a first direction from the closed position to the open position; one or more second blades arranged to rotate in a second direction opposite to the first direction from the closed position to the open position; the backdraft damper further including a linkage between the one or more first blades and the one or more second blades to cause the first and second blades to together rotate between the closed and open

Abstract: A backdraft damper for permitting a flow of air in an outflow direction and preventing the flow of air in a backdraft direction has a frame provided with a transverse opening allowing the passage of air through the frame. One or more blades extend across the frame and are mounted to the frame about a central portion by pivot members, for rotation between open and closed positions.

Abstract: A damper comprises a generally rectangular frame extending between opposed open faces and defining an airflow region. One or more damper blades comprises a substantially air-impermeable vane pivotally mounted between the sides of the frame and pivotable between an open position and a closed position. In the closed position an edge of the adjacent blade abuts a blade stop surface formed along each end, such that in the closed position one edge of the blade adjacent to each end of the frame extends into a recess and abuts the blade stop surface, to prevent air from flowing between the blade and the end of the frame. In the preferred embodiments the blade stop surfaces are integrally formed in each end panel.

Abstract: A damper comprises a generally rectangular frame extending between opposed open faces and defining an airflow region. One or more damper blades comprises a substantially air-impermeable vane pivotally mounted between the sides of the frame and pivotable between an open position and a closed position. In the closed position an edge of the adjacent blade abuts a blade stop surface formed along each end, such that in the closed position one edge of the blade adjacent to each end of the frame extends into a recess and abuts the blade stop surface, to prevent air from flowing between the blade and the end of the frame. In the preferred embodiments the blade stop surfaces are integrally formed in each end panel.

Abstract: A backdraft damper for permitting a flow of air in an outflow direction and preventing the flow of air in a backdraft direction, including a frame having a transverse opening allowing the passage of air through the frame; a plurality of blades, each blade extending across the frame and mounted to the frame about a central portion by pivot members, for rotation between an open position in which the blade allows air to flow through the frame and a closed position in which the blade blocks air from flowing through the frame, the plurality of blades including one or more first blades arranged to rotate in a first direction from the closed position to the open position; one or more second blades arranged to rotate in a second direction opposite to the first direction from the closed position to the open position; the backdraft damper further including a linkage between the one or more first blades and the one or more second blades to cause the first and second blades to together rotate between the closed and open

Abstract: A backdraft damper for permitting a flow of air in an outflow direction and preventing the flow of air in a backdraft direction has a frame provided with a transverse opening allowing the passage of air through the frame. One or more blades extend across the frame and are mounted to the frame about a central portion by pivot members, for rotation between open and closed positions.

Abstract: A damper comprises a generally rectangular frame extending between opposed open faces and defining an airflow region. One or more damper blades comprises a substantially air-impermeable vane pivotally mounted between the sides of the frame and pivotable between an open position and a closed position. In the closed position an edge of the adjacent blade abuts a blade stop surface formed along each end, such that in the closed position one edge of the blade adjacent to each end of the frame extends into a recess and abuts the blade stop surface, to prevent air from flowing between the blade and the end of the frame. In the preferred embodiments the blade stop surfaces are integrally formed in each end panel.