Maglok.. Magnetic Closure Device for Butterfly Dampers

Maglok® is a patented device which eliminates the annoying banging of butterfly shutters on ‘HC’, ‘SS’ and some New Generation* style vertical discharge axial roof ventilators. It also helps protect against rain ingress due to stack effect or wind action that may cause the shutters to lift open when the fan is not running.

• Provides positive closure on various butterfly shutters.
• Compact size and has no moving parts.
• Is unaffected by heat and moisture.

Ideal for installations in high wind areas or on buildings where the internal pressure, or stack effect causes the shutters to open when the fan is not running.

Maglok-2 and Maglok-5 utilise a specially selected rare earth magnet that is three and half times more powerful than ferrite. The housings are constructed from corrosion resistant aluminium, incorporate stainless steel adjustment screws and have long life corrosion protected striker plates.

There are 2 models in the range: -

• Maglok-2: 1-2 kg range
• Maglok-5: 3-5 kg range

The holding force of both Magloks is fully adjustable within their load range

Depending on what holding force is selected, protection can be provided to the same integrity as the roof structure according to the requirements of AS/NZS 1170.2:2011 - Structural design actions Part 2: Wind actions.

Generally speaking the maximum holding force available should govern selection.

The appropriate Maglok® can be selected from the graphs which show the minimum stall pressure which must be generated by the fan to open the butterfly shutters and the approximate wind speed a fan would be protected against.
The wind speed can be determined from a detailed study of the individual installation in accordance with AS1170.2.

Check the selected fan curve to ensure its pressure capacity is in excess of the stall pressure required. Between them, the Maglok-2 and -5 can be adjusted infinitely to provide any force from 1 to 5 kg providing a wide range of choice of stall pressures and wind loadings.

For fans of 800mm diameter either the Maglok-2 or -5 can be selected.

If the fan selected is less than 1000mm diameter and does not have sufficient stall pressure to overcome the 1kg loading, a Maglok® may not be a possible solution.

Simply nominate the Maglok® model determined from the selection process and order accordingly.

* Please call our sales representative to confirm suitability for use on the New Generation Axial roof units.