Abstract: Devices in burners, for examples oil burners, with a feed tube (12) and a burner retainer (13,15) inserted into the same. The air stream in the feed tube is made to be affected by a retarding shield (20) positioned ahead of the burner retainer (13,15) and having a central aperture for the flame and a substantially circularly surrounding gap (18) between the retarding shield (20) and the inner periphery of the feed tube, and by a flange (19) extending rectangularly inwards from said inner periphery and which is positioned in spaced relation to the retarding shield in the direction of flow of the air.