Patent ID: 6983565

Claim:
A closure system for comprising: a doorframe mounted in a wall and defining an entry between a cold space on one side of the wall and a warm space on the other side of the wall; a movable door panel having a periphery and selectably disposable against the doorframe to at least partially block the entry when in a closed position, the door panel substantially unobstructing the entry when in an open position; a sealing member positioned between and attached to a selected one of the doorframe and the door panel periphery and operatively configured to form an air seal with the other of the doorframe and the door panel periphery when the door panel is in the closed position; and a frost control system to prevent ice forming on the sealing member, comprising: an air passage communicating between the cold space and a doorframe port attached to the doorframe proximate to the periphery of the movable door panel when in the closed position, an air heater in the air passage to warm air from the cold space; and an air channel defined internal to the movable door panel proximate to the periphery and including an inlet port communicating with the doorframe port to receive warmed air therefrom; an air mover in communication with the air passage to move the warmed air through the air passage to the air channel of the door panel.