| 摘要 |
The invention relates to an annular building block (10) for a chimney stack, whose outer faces (12, 14, 16, 18) are configured to have a brick-type appearance and whose inner face (20) is substantially cylindrical. The aim of the invention is to provide annular building blocks that allow for an exact and rain-proof mounting even by inexperienced personnel. To this end, the top edge (22) of every outer face (14) is provided with a recess (24) and the bottom edge of every outer face (14) is provided with a projection (30) projecting from the lower side (28) so that when two annular building blocks (10) are placed one on top of the other, the recess (24) of the bottom annular building block (10) engages with the projection (30) of the top annular building block (10). |
