When it comes to dampers, often manufacturers’ representatives get questions like “what is the best damper to buy for a duct system?”
And as is always the case in any specific application the answer is “it depends.”
In other words, it depends on what the damper needs to do. For instance, if you require tight shut off the best damper would be something like a butterfly, or a guillotine damper (also called a knife gate) that will have a good sealing edge to prevent or greatly reduce flue gases from bypassing around the contact surfaces.
If you are looking for a high degree of modulation then a louvre damper will provide this over a butterfly damper that often has more course modulation characteristics especially with hysteresis.
Not to mention, of course that everybody must work to a budget. By simplifying the mechanisms and the amount of metal along with reducing the amount and degree of fabrication will result in a lower cost. And here’s where a butterfly damper will have the advantage.
If there is a lot of particulate in the flue gas which ends up accumulating on the contact surfaces then a guillotine damper can be the best choice as it has the capacity to push through accumulated material.
Within the various choices of dampers there is a whole range of metallurgy and design features specifically implemented to look after the particular application, whether it is in oil and gas, mining and minerals or power.
Many engineered-to-order damper and expansion joint suppliers – such as Effox or Flextor, will be able to do computational fluid dynamics (CFD) calculations to determine whether material might get hung up, what pressure drops will occur through the ducting and dampers and expansion joints at various flow volumes, or where erosion could occur.
Well-designed systems that operate trouble-free are always a combination of a strong collaboration between the supplier, the consultant, and the end-user.
If you have any questions about dampers and expansion joints feel free to send an email to the address below.