| 摘要 |
<p>1,234,465. Moulding tubes. WAVIN N.V. 27 Aug., 1968 [1 Sept., 1967], No. 40919/68. Heading B5A. In a process for making a perforated fibre reinforced plastics tube, a former or mould surface 2 on a mandrel 1 having projections 3 is coated with fibres e.g. by winding, and then with a thermosetting resin but the tops of the projections are left uncovered so that when the former 2 is destroyed e.g. by melting or dissolving, the resulting pipe has perforations where the projections were. Centrifugal casting is suggested.</p> |
