VENTS VDO series

• The fans are used for extraction of smoke in case of fire and removal of hot air outside.

• The fans are also used for general ventilation systems.

• The fans are rated for permanent operation at ambient air temperatures from -60 °C up to +50 °C (depends on climatic category, see the Designation key).
• The fans are able to operate 2 hours at the temperatures +300 °C and +400 °C.

• The fans with a fire resistance class of 200 °C/2 hours can be produced on request.
• The characteristics of the 200 °C/2 hours fans are completely identical to 300 °C/2 hours fans.

• The fan consists of a casing, an impeller and a motor.
• The metal casing with rolled flanges helps achieve outstanding rigidity and minimum clearances between the casing and the blades.
• There is an inspection hatch in the casing for easy maintenance.

• All the casing components are powder coated for improved protection against the environmental effects.
• The weight of the fans may differ from the one stated in the catalogue and depends on the components used (motor, terminal box, etc.).

• The fans are equipped with three-phase (400 V/50 Hz) motors.
• Motor ingress protection rating is IP55.
• Depending on the model, the fans have single- or double-speed modifications.

• The single-speed models are equipped with 2-, 4- or 6-pole motors.
• The double-speed models are equipped with 2/4-, 4/6- or 4/8-pole motors.

• Depending on the size and the required air capacity the fans are equipped with impellers with 4, 5, 6, 7, 8, 9 or 12 blades angled from 20° to 50° to ensure precise matching of fans with the operating point.
• The specially designed impeller blades ensure high efficiency of the fan while keeping noise well under control.

• The impellers are dynamically balanced.
• Low weight and low moment of the impeller inertia help reduce the fan start-up time.
• The fan blades are made of cast aluminium.

• The fans can be mounted on any flat surface or directly into a ventilation duct.
• The units are suitable for both horizontal and vertical configurations.

• Installation in the air duct requires flanges to attach the fan to the ductwork.
• To attach the fan to the floor, the wall or the ceiling use the O-VO carriers (not included as standard, should be purchased separately).

Fan installation with no upstream ducting

• Axial fans without upstream ducting must be equipped with the VK-VO inlet cone to improve the air flow parameters.

Fan installation into an air duct system:

• To ensure a uniform air flow the fan should be preceded by a straight duct section with a cross-section area equal to half of that of the fan.
• The length of the duct section should be 3 ÷ 4 D (D is the inner diameter of the fan).
• The length of the straight duct section downstream of the fan should be 1.5 ÷ 2 D.
• Reduction of the recommended duct length values results in a drop of the fan pressure and performance.
• To reduce noise and vibration use the VVGF flexible joints.

Fan installation with no downstream ducting:

• If the axial fan is a terminal device of the ventilation system (i.e. there is no downstream ducting) the unit must be equipped with a diffuser to reduce the air flow velocity and the fan dynamic pressure.
• Reduction of the air discharge velocity results in a significant reduction of shock losses which are proportional to the square of velocity decrement.
• The fan should not be equipped with a downstream contractor.

Installation near bends:

• To install the fan directly downstream of a bend (elbow) use a curved section with a large bending radius or an array of internal guide vanes.

Changing diameter installation:

When changing from a smaller diameter to a larger one use a connector diffuser with the maximum opening angle of 12°.

Obstructed space installation:

• To ensure normal operation of the fan in an obstructed space make sure to provide for a sufficient distance between the inlet and outlet flanges and the floor, walls, bulky equipment and obstacles.