Frame-supported membrane for chimney

Claim 1

A frame-supported membrane structure for a chimney column, comprising: an upright, gas-tight tubular membrane made of thin, corrosion-resistant material, said membrane including a plurality of axially spaced, circumferentially extending corrugations for accommodating axial expansion and contraction of the membrane; a relatively open skeletal framework that generally coaxially surrounds the membrane throughout most of the height of the membrane; generally radially extending means mechanically hanging the membrane from the framework at a large plurality of axially and angularly distributed sites, these hanging means including means for accommodating radial expansion of the membrane from a datum disposition and for accommodating contraction thereof back to that datum position, but for restricting further substantial contraction, so as to restrain against any implosive force which may act on said membrane; basing means provided on said framework in a lower end region of said framework, this basing means being constructed and arranged, when resting on a fixed foundation, to provide substantially all of the necessary vertical support for the framework and membrane; said basing means comprising: a girder means extending perimetrically about the framework as a part thereof in the vicinity of the lower extent of the framework; a base having a plurality of upwardly facing shoulder surfaces provided thereon at angularly spaced sites generally in a common horizontal plane; a plurality of grillage bars fabricated into a grid having at least a generally central cell and a plurality of bar end portions extending laterally outwards in relation to said central cell; at least some of said bar end portions being supported upon respective ones of said shoulder surfaces of said base; and said girder means resting on said grid on said generally central cell.