Concrete-sheathed layered fireplace chimney building block - with single-unit sheath and flue duct, and intervening cutouts

摘要

The building block element comprises a tubular sheath made of concrete, a smoke ducting section inside this made of a fireproof mass, and an insulating wall, at an interval between these, made of fire -resistant inorganic material. The tubular sheath (2) forms a single shaped unit with the tubular smoke duct (3); in the cross-over area between them there is a series of cutouts (7), firstly to import sufficient rigidity for transport, and secondly to make it possible for the cross-over area to rupture when the chimney is assembled, as a result of the unequal coefficients of expansion of the two tubular sections. The intervening spaces between these and the insulating wall (4) may be filled with vermiculite or similar material.