| 摘要 |
A filter for use in a concrete press mould comprises a fabric (19) knit or woven at least in part from hydrophobic, eg PVC or polypropylene, having a fabric density which permits the passage of water therethrough but prohibits the passage of particulate material. The fabric may be bounded around its periphery with at least one continuous imperforate band formed by fushion of the yarns. The filter may comprise a perforated plate (14) and a sponge layer (41), e.g. of foamed plastics. A preferred fabric is warp knitted with the use of a fall plate to produce floats on the face of the fabric. Flat yarn may be used. <IMAGE> |
