Heat exchanger clean-out plug assembly
A flue-gas to air heat exchanger having a flue-gas containing shell with a heat exchange surface, flue-gas inlet and outlet sections, and at least one tubular clean-out fitting is provided with a removable plug having an outer peripheral portion resiliently engageable with a section of the inner peripheral portion of the fitting adjacent the shell. The plug periphery is expanded into gas-tight sealing contact with the fitting inner periphery by means affording installation and removal without tools.
1 . In a flue-gas to air heat exchanger having a flue-gas containing shell with a heat exchange surface, said shell having flue-gas inlet and outlet sections and at least one tubular clean-out fitting having an inner peripheral portion of a predetermined length extending away from said shell to afford access to the interior of the shell for cleaning the shell interior, the improvement comprising:
a removable plug having an outer peripheral portion resiliently engageable with a section of the inner peripheral portion of said fitting adjacent said shell, and
means for expanding said plug section into gas-tight sealing contact with said fitting inner periphery.
2 . Apparatus according to claim 1 wherein said plug includes a resiliently deformable tubular body having opposite end surfaces, a distal disc engaging one of said body end surfaces and extending transverse to said fitting, a proximal disc engaging the other of said body end surfaces and extending transverse to said fitting, and means for urging said discs axially toward one another for peripherally expanding said tubular body into sealing engagement with the inner periphery of said fitting.
3 . Apparatus according to claim 2 wherein said proximal disc is larger than said distal disc and extends across the outer end of said fitting, and said tubular body is coextensive with a substantial portion of said predetermined length of said fitting.
4 . Apparatus according to claim 3 where said means for expanding said tubular body includes a rod extending axially through said proximal disc, and means adjacent said proximal disc for tensioning said rod axially and thereby effecting said expansion of said plug body.
5 . Apparatus according to claim 4 wherein said means for tensioning includes threads on said rod extending through said proximal disc, and a nut engageable with said threads and rotatable relative thereto in engagement with said proximal disc.
6 . Apparatus according to claim 5 including a hand grip carrying said nut to afford manual turning thereof.
7 . Apparatus according to claim 2 wherein said plug body is of heat-resistant elastomeric material.