Casting apparatus and method.

摘要

Casting apparatus comprising a dispenser (4,5) defining a dispensing chamber (21) of variable volume receiving molten metal (3) in use, a valve (8) having a housing (23) defining a valve chamber (24) and a passageway (7) communicating between the valve chamber and the dispensing chamber, the valve further defining an inlet port (8a) communicating with a supply (2) of molten metal and further defining an outlet port (8c) communicating with a die (9), a valve member (8d) located in the valve chamber, actuating means (26) selectively operable to move the valve member into a first position closing the inlet port and a second position closing the outlet port whereby in the first position the valve connects the dispensing chamber with the die for casting metal and in the second position the valve connects the dispensing chamber with the supply of molten metal for recharging the dispensing chamber, the valve including first and second annular seats (41,42) surrounding the inlet and outlet ports respectively and engageable by respective first and second annular sealing surfaces (47,48) of the valve member in the first and second positions respectively and wherein the actuating means comprises a stem (25) fixed to the valve member, a linear actuator (27) operable to provide reciprocating axial movement of the stem and rotating means (15) operable during axial movement of the stem to rotate the stem so as to vary the relative contact position of the respective seat and sealing surfaces. The apparatus is useful in casting low melting point alloys to provide cores for moulding hollow articles in plastics materials.