Abstract: A system and method for rapidly and reliably sealing off a selected opening from the passage of smoke, noxious fumes, or contaminated air includes a powered clutch and viscous governor that provides a fail-safe mode of operation. A curtain is positioned in a housing adjacent to an upper limit of an opening such as a hoist access-way. The curtain is wrapped around a spindle that is connected to a spool via two cords. The curtain is held in the housing in a stored configuration by a powered clutch so that upon removal of power, either via a controller or by power loss, the clutch releases the spool allowing the cord to unwind lowering and thus deploying the curtain. A capacitor can be included to prevent inadvertent deployments due to momentary power loss. The speed at which the spool rotates, and correspondingly the curtain deploys, is limited by a viscous governor coupled to the spool.

Abstract: A system and method for rapidly and reliably sealing off a selected opening from the passage of smoke, noxious fumes, or contaminated air includes a powered clutch and viscous governor that provides a fail-safe mode of operation. A curtain is positioned in a housing adjacent to an upper limit of an opening such as a hoist access-way. The curtain is wrapped around a spindle that is connected to a spool via two cords. The curtain is held in the housing in a stored configuration by a powered clutch so that upon removal of power, either via a controller or by power loss, the clutch releases the spool allowing the cord to unwind lowering and thus deploying the curtain. A capacitor can be included to prevent inadvertent deployments due to momentary power loss. The speed at which the spool rotates, and correspondingly the curtain deploys, is limited by a viscous governor coupled to the spool.

Abstract: A system and method for rapidly and reliably sealing off a selected opening from the passage of smoke, noxious fumes, or contaminated air includes a powered clutch and viscous governor that provides a fail-safe mode of operation. A curtain is positioned in a housing adjacent to an upper limit of an opening such as a hoist access-way. The curtain is wrapped around a spindle that is connected to a spool via two cords. The curtain is held in the housing in a stored configuration by a powered clutch so that upon removal of power, either via a controller or by power loss, the clutch releases the spool allowing the cord to unwind lowering and thus deploying the curtain. A capacitor can be included to prevent inadvertent deployments due to momentary power loss. The speed at which the spool rotates, and correspondingly the curtain deploys, is limited by a viscous governor coupled to the spool.