Non-return flap, for the gas/air flow channel from the fan blower to the gas burning surfaces in a multi-stage gas burner, is a thin blade mounted at one end with a seal around its circumference and tensed against the channel wall

摘要

The non-return flap, for the gas/air flow channel to burner surfaces, has a thin-walled metal blade flap (1) which can be shaped. Its shape structure and sealing (2) around it gives a pretension against the gas/air flow direction from the fan blower. The flap is fitted at a single mounting point (3), with a curvature from the mounting to the free end of the flap, to give the pretension.