Self adjusting chimney cowls
Self-adjusting chimney cowls are mounted on a rotating mechanism, set up under the direction of the wind, shielding the flue outlet. On the leeward side of a vacuum is created, which strengthens the chimney draft. They can be mounted on ventilation ducts, smoke and gases. They are more efficient than fixed epiphysis. They are characterized by the most fanciful shapes of all the epiphysis (like eg. The plume or sail).