Stadium Black Hole Ventilator Set BM720

'The Original Black Hole Ventilator' Comprising;

• Double rustic red louvred airbrick, cavity liner with cavity drip and anti-draught baffles extension piece and white inner grille.
• Invertible for high or low fitting.
• Expands to fit solid or cavity walls 290 mm to 390 mm
• Rated Input - Max 21kW (71,500 Btu/h

The Benefits of a 'Black Hole®'

• Stops wind blasting in - the air flow within the duct is slowed down by the change of direction and by the vortices formed, reducing draughts to a minimum.
• Stops light showing through - the occupier cannot see through the ventilator and is less likely to be worried that insects and vermin may enter the house through it.
• Stops light shining out - night flying insects like moths, crane flies and mosquitoes are not attracted in.
• Absorbs outside noise - reduces the penetration of traffic noise. The internal construction works as a sound baffle.
• Allows air to be pulled through by the appliance when it is operating.
• Safety - with draught and light annoyance problems eliminated, the occupier will not be tempted to block off the vent.

The 'Black Hole®' Magic Explained

As outside wind pressure increases, a normal ventilator lets more air through causing annoying draughts.

Inside the Stadium 'Black Hole®' Ventilator vortices are formed behind the internal blades as the incoming air is forced to change direction. The gap that the air is able to pass through narrows. As wind pressure increases, the vortices grow, so reducing the total air flow, finally tumbling and slowing to a trickle, thereby cutting down annoying draughts.

However, when the heating appliance is operating, air is drawn through the vent and actually speeds up within the constricted air flow between the vortices, thus maintaining the correct amount of air into the room or compartment to allow the fuel to burn efficiently and flue gases to escape.

When the appliance is not working, incoming air is reduced to a minimum, even on windy days. The actual physical difference is that of air blown or drawn. The energy of the blown air (wind) is quickly dissipated by the restriction of the internal shape and the vortices, while the drawn air will flow smoothly round the vortices.