| 摘要 |
A prismatic mould of rectangular cross-section is used for making blocks, esp. very large blocks of an expanded plastics esp. polystyrene. The mould is desinged to withstand internal fluid (steam) pressure and is constituted of two parts which are permanently connected together by two hinge joints, one or both of which comprises an eccentric. Thus, rotation of these eccentrics enables the two parts to be moved apart sufficiently for the moulded block to be withdrawn from the mould. Pref., each part is an angle-section and they move relative to each other along a diagonal of the cross-section of the mould. Esp. in modern processes for the prodn. of very large expanded polystyrene blocks, where an initial steam pressure of 5-10 kp/cm2 is used. The arrangement enables the mould to ge safely kept closed against this pressure, while enabling it to be readily opened for the block to be subsequently removed, before contraction has taken place. |
