| 摘要 |
<p>A nozzle valve nozzle suitable for use with gas assisted moulding apparatus. The nozzle valve has a body (30) which defines a passage (38) for plastic and includes a means for closing off the passage, which means may be a ball valve (39). The valve body (30) also defines a gas injection port (34) for the supply of gas under pressure to plastic supplied through the passage (38), and includes a means for isolating (40) the gas injection port (34) from the passage (38) and a means for activating the means for isolating (40) under the control of gas pressure. The means for isolating the gas injection port can be a spring loaded needle valve (40) arranged to open under gas pressure. A means for assisting the means for closing off the passage (38) can also be provided, in the form of a piston (32) arranged to close the ball valve (39) under the influence of gas pressure supplied via a further gas port (35).</p> |
