Gravity operated leaf-type backdraft damper – leaf damper. It diff ers from conventional (single-blade) backdraft dampers by its low response time and lower standard minimum fl ow rate required for its opening. The blades of such dampers open under the action of air fl ow and automatically return to their original closed position when the air supply is stopped. It is especially important to use such a damper together with axial fans, which, as a rule, have a lower fl ow rate at the outlet compared to radial fans.

They are made only of rectangular cross-section in three main design versions:

• ТUL-1 – for operation on horizontal sections of the air duct (installed vertically);
• ТUL-2 – for operation on vertical sections of the air duct (installed horizontally) when the air fl ow moves from the bottom to top (air extract);
• ТUL-3 – for operation on vertical sections of the air duct (installed horizontally) when the air fl ow moves from top to bottom (air supply).

Design: