Self regulating flow mixing limiter for building ventilation duct has flow regulating flap with propeller to vary effective flow

摘要

The self regulating flow mixing limiter for a building ventilation duct has a housing with a main axis supporting a closure flap (3) and a propeller (4). The flap and propeller are rotatable around their axes to vary the effective flow. There is a spiral or spring which operates against the torque of the propeller. An adjuster (10) is provided for the axis (12) at right angles to the main axis to provide a preload for the spiral or spring against the main axis.