Chimney cowl is a device, which, in a dynamic way, uses force of the wind to increase chimney draught and have different operating principles, purposes and performances. They are mounted on the top of chimney ducts. Their purpose is to prevent the chimney from downwind, rainwater and bird nesting, but most of all they are designed to generate chimney draught using force of the wind.Chimney Cowl are divided into the following groups:
Self-adjusting chimney cowls - are devices, which, in a dynamic way, use force of the wind to increase chimney draught. The cap always places itself in the opposite direction to the wind no matter of its strength or direction. They can be mounted on ventilation ducts, smoke and gases.
Static cowls - they use the kinetic energy of the wind to generate a vacuum in the chimney. They do not change their position relative to the blowing of air. They are used at the ends of ventilation ducts and flue gas.
Rotary chimney cowls - are devices, which, in a dynamic way, use force of the wind to increase chimney draught. The turbine always rotates in the same direction no matter of the wind strength or its direction. They are to be mounted on gravitation based ventilation chimney duct endings.