US Patent 7174734 Refrigerator damper with PTC heater actuation

A damper in a refrigeration system having a first compartment and a second compartment connectable through a passageway is provided. The damper comprises a damper door, a temperature responsive unit, and a heating element. The damper door is moveable between an open position and a closed position. The temperature responsive unit is operatively coupled to the damper door. The heating element is coupled to one end of the temperature responsive unit to conductively heat the temperature responsive unit when activated. The temperature responsive unit expands to move the damper door to the open position in response to conductive heating from the heating element.