| 摘要 |
<p>The hollow body (3) intended to contain gases or liquids, is manufactured by using cores (1) intended to form cavities, which, after hardening, are removed by washing with a solvent or burnt during the hardening process. The cores (1) have recesses (2) providing, after stripping of the hollow body (3), special inner profiles, for example bars or support ribs. The cold workable and hardenable material of the hollow body (3) may be concrete or ceramic. In the first case, the core (1) is preferably comprised of polystyrene foam and in the second case the core (1) is also comprised of cellulose pulp, for example cardboard pulp.</p> |
