Our patent also covers reversing operation of ceiling fans!
In commercial buildings, there is the customer requirement for individual projects that the devices heat in the ceiling area
aspirate and press through skylights / RWA openings to the outside. The special version of the turbulators
is switchable between conveying direction downwards (gentle turbulator operation) and conveying direction upwards.
Extraction in the roof area and vertical-strong blowing upwards.
The speed and air flow are infinitely adjustable via 0-10 V signal in both conveying directions. This can be a
under the roof located "warming bell" are better pressed outward.

Heat recovery in winter
Ventilation in summer eg.
in the morning + in the morning
Outside air entry via
open skylights / RWA`s

Extraction of the heat bell /
Support the existing
thermal buoyancy +
Escape over open
Skylights + RWA`s im

Summer after-work
Ideal in salesrooms

Normally motor drives are running up with full motor-power when starting-up a ventilator, the negative side effects are that vee-belts can't be instantly accelerated from zero to full-transmission operation, the vee-belts get shifting and are causing a squeaky noise.

Besides the acoustic disturbance a decreased vee-belt life-span is also resulting from wearing and tearing. To avoid those appearances we have developed the Doll Smooth-startup-up devices for equipment of new systems ex works and after-market equipment of existing Doll-systems.