rookklep

Rookklep is a term used in Dutch engineering to denote a flap or valve that controls the flow of combustion gases in chimneys and flues. The word combines rook, meaning smoke, and klep, meaning valve or flap. In many systems a rookklep is a simple hinged plate that sits inside the flue or throat and is designed to open when there is a positive draft from the fire and to close when wind or external pressure would push smoke back into the room.

Most rookkleppen are gravity-operated; heat from the fire helps keep the plate open, while cooler air or lack of heat allows the plate to close and restrict backflow. Some variants use springs, or automatic actuators and thermostats for homes with more complex ventilation needs. Materials commonly include steel or cast iron, chosen for durability and heat resistance.

Applications include residential fireplaces and wood stoves, as well as certain industrial flues and boilers. The device serves to reduce downdrafts, improve draft control, and limit backflow of smoke when winds or pressure changes affect the chimney. Variants range from simple manual dampers to more sophisticated automatic systems integrated with other flue controls.

Maintenance is straightforward but important: periodic cleaning to remove soot, inspection of hinges or seals, and verification that the damper opens and closes smoothly. A rookklep is most commonly encountered in traditional masonry chimneys and older heating installations, though modern flue systems may incorporate equivalent dampers under different names.

See also dampers, chimney damper, backdraft damper.