| 摘要 |
A gas injector comprises a tube connected with a source of pressurized gas, and designed to open out at one end into the cavity of an injection mould of plastic material to provide for the swelling of this plastic material and the making of a hollow part. The one end of the tube forms a seat for a sealing valve having a rod which extends inside the tube and is spring-actuated to effect closure of the valve. The rod is also subject to the action of means in the form of an electromagnet which includes a solenoid to bring about the opening of the valve against the spring. The plunger of the electromagnet is within a cavity associated with the tube while the coil of the electromagnet is outside the cavity.
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