Patent ID: 7169039

Claim:
An air duct closure device to prevent a flow of air and foreign agents, comprising: a normally open air damper device including an inlet and an outlet, the air damper device being connected in-line in a respective portion of a duct in an air duct system; a rotatable sealing damper in the normally open air damper device, the sealing damper rotating from a normally open position to a closed position when the air duct closure device is activated and seal off, when the sealing damper in the normally open air damper device is in the closed position the air duct closure device and prevent air and foreign agents from flowing through the normally open air damper device and the air duct system; a normally closed air damper device including an inlet and an outlet, the air damper device being connected in parallel across a respective portion of the duct in the air duct system; and an over pressurization control device connected to the normally closed air damper.