Other

Jeff Shea

Douglas C Williams

Michael S Cork

A fume exhaust duct joint, a clamping collar for clamping two cylindrical dual-laminate duct sections joined by an internal slip collar, and a method for assembling the joint. A first embodiment of the clamping collar has two clamp portions each including a metal outer skin spot-welded to a metal inner skin. The inner skins have bifurcated protrusions whose bifurcations penetrate the duct section outer surfaces when the collar is tightened, and, optionally, two circumferential beads of fire retardant caulking. The inner skins and slip collar are bonded to duct section surfaces using a putty-like sealant including a settable admixture of curing agent and novolac epoxy resin. A second embodiment of the clamping collar, preferred for duct sections 3-inches in diameter or smaller, has a single circumferential clamp portion.

Fume duct joint with clamping collar

Sealant compositions for sealing the circumferential joint between pairs of dual-laiminate fume duct sections, and a joint sealing method enabling strong bonding between the sealant and phenolic/glass and vinyl ester surfaces without sanding mating surfaces. A first preferred sealant consists of a resin including by weight: 20.0% Epon 862 novolac epoxy resin; 30.0% SU-2.5 Epon novolac epoxy resin; 20.0% Heloxy 48; 19.5% Epon 826 bisphenol A resin; 10.0% Heloxy 505; and 0.5% silane, and a hardener including: two cycloaliphatic amines, 94.0%; and an aromatic tertiary amine, 6.0%. A second preferred sealant consists of a resin including by weight: 39.5% aromatic epoxide resin; 40.0% Heloxy 48; 20.0% SU-2.5 Epon novolac epoxy resin; and 0.5% silane, and a hardener including: two cycloaliphatic amines, 94.0%; an aromatic tertiary amine, 5.5%; and an amino silane, 0.5%.

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San Francisco, CA, United States of America

Jeff Shea