Guillotine Isolators

Simplex – fitted to the periphery of the blade is a series of flexible metallic looped and leaf-spring sealing elements. These seals are constructed of austenitic stainless steel or high nickel alloys, depending on the operating conditions. They are designed to seal against both continuous landing bars in the duct framework of the isolator and to provide a sealing margin of at least 30 mm. The metallic seals alone, give a sealing efficiency of 99.95% or better, on cross-sectional area.
Duplex – 100% tightness, required to ensure complete safety for maintenance personnel working in an isolated section, is attained by creating, with a small fan, an air barrier in the inter space between the two sealing surfaces. The pressure zone, set at approximately 50 mm. H2o above the expected duct pressure, does not pump them up. This sealing arrangement has the additional advantage that it provides an automatic venting arrangement if there is a sudden pressure surge. Thus if the first sealing surface pushed off, the second, nearest the isolated section, is pressed even tighter against its landing surface and the gases are vented to atmosphere through the fan.