Guillotine dampers can be manufactured in round, square and rectangular configurations or in any combination of the three.Guillotine frames are constructed from a combination of heavy structural channel, structural shapes, and plate. Certain Guillotine configurations require the use of heavy formed channel. Formed channel is typically required for split body configurations or if an uncommon flange to flange dimension is specified.
Standard material for construction is A-36 steel, but any weldable alloy can be provided. A-36 Guillotine blades are supplied as standard. For high temperature or very corrosive applications, the blade can be provided in corten, 387GR11, or some grade of stainless alloy. The leading edge of the blade is beveled to allow the blade to shear through any build-up of material that may accumulate in the seat area.
Mader designs the blade to keep deflection to an absolute minimum. On applications where size, temperature, and pressure dictates a blade thickness of 1-1/4″ or greater, Mader recommends the use of an anti-deflection bar. An anti-deflection bar(s) will allow the use of a thinner blade. Another option would be to utilize a sandwich blade design. With a sandwich blade design the use of two thinner plates with gusseting between can provide a lighter, stronger blade design for larger, high pressure service applications.
Mader recommends the use of bonnets on high temperature or positive pressure applications. Bonnets will provide less thermal shock when bringing a cold blade into a hot duct on high temperature services. Bonnets will also eliminate any gas leakage to the atmosphere on positive pressure systems. Bonnets can be supplied with either one side or both sides removable. With a negative pressure system, bonnets are not required unless leakage of outside atmospheric air is prohibited.
Guillotine dampers can be provided with a refractory lined housing and an alloy blade to permit high temperature service and still utilize a carbon steel frame.