| 摘要 |
Apparatus for producing a cement sheet, including a rotatable mould into which a cement mix is fed to form a soft, centrifugally moulded cylinder, which is then removed from the mould, divided longitudinally, and laid out flat to harden. The mould is initially fitted with a flexible liner of metal, rubber or plastics. The soft cement cylinder is removed by means of a mandrel inserted into the cylinder while in the mould. During removal from the mould, the cement cylinder is held onto the mandrel either by vacuum applied to perforations in the wall of the mandrel, or by connecting together the edges of the liner which surrounds the cylinder while it is removed from the mould on the mandrel. The longitudinal division in the cement cylinder may be formed by a longitudinal inwardly projecting member within the mould or forming part of the liner, or by slitting the cylinder on the mandrel after its removal from the mould. The apparatus is particularly useful for producing small quantities of asbestos cement sheets with special laminations or surface effects. Apparatus in accordance with the invention may be used for producing sheets of flowable hardenable material other than cement.
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