What Are the Spinning Discs on the Roof of Vans? (Solved)

Ever been behind a van and seen a spinning grey or black disc and wondered what they are and what they do?

I wondered that too, so I found the answer.

Those spinning discs on van roofs are called “Flettner vents”, they are utilised while transporting animals or food. Because the back of vans do not have windows, it is necessary to find another method of circulating fresh air, it also removes any smell.

Essentially, they draw out the air from the back of the van through this vent.

Since 1931, Flettner Ventilator has been a major manufacturer of spinning air vents for vans.

Whenever a Flettner roof vent is mounted on a vehicle's roof and air is moving around it, either as a result of the vehicle's movement or as a result of the wind itself, the Flettner roof vent will spin and ventilate the vehicle.

Sometimes, there may be another brand of roof vent used but it will be based on the same principle.

Two or more different vents may be used in conjunction with each other.