Revolving (spinning) chimney cowls are designed to cure the problems caused by downdraught. The cowl spins, either when the wind blows, or when your appliance is burning well, when the heat on the underside of the cowl will make it spin.
Rotary/Spinning chimney cowls. Their heads are amazed by the wind in rotation. Inside the chimney vacuum arises (the stronger the wind, the bigger), which increases and stabilizes the string and prevents string reverse. They are very efficient. They can be used on ducts.
Our ship offers chimney spinning cowls in sizes from 130mm to 500mm in base diameter.