Heavy duty, round throttles are intended for cutting-off (using a round shutter) of ventilation ducts at the uper deck, in case the height of ventilation ducts above the deck is low. The position of throttle’s shutter is controlled with manual actuating device (manual knob, lever).

For remote control, valves with electric, compressed air or hydraulic servo-motors can be supplied. Throttles are adjusted to sizes of ventilation ducts of diameters of ø 150÷1250.