| 摘要 |
586,386. Dielectric heating. BRITISH INSULATED CABLES, Ltd., PACKER, J. L., and STEWARD, H. M. Jan. 17, 1944, No. 2872/46. Divided out of 586,158. [Class 39 (iii)] [Also in Group V] In an extrusion machine having a head 8 disposed transversely of the barrel .12, the head includes a high frequency heating device comprising a pair of electrodes, one, 14 being formed by or carried on the wall of the head and surrounding the other 21, which is formed by or carried on a central member supported from the wall of the head. The high tension electrode may be the outer one, but as shown is the inner one and is formed by a metal sleeve 21 supported on an insulating liner built up of ceramic (rutile) rings 25 surrounding a core tube part 18a which is centred by screws 20. The electrode is fed by a coaxial cable 40 which passes through the core tube 18. The earthed electrode is the wall 14, which may be faced with heat-resisting insulating material in which heat is generated to prevent chilling of plastic material as it flows past the earthed electrode. The head may be fitted with a steam jacket. The electricity supply may be controlled by the starting member for the motor which drives the machine, the heat being switched on 15 seconds before the motor moves and switched off 15 seconds after the motor stops. A wire to be coated travels through the tube 18. Specification 586,158 is referred to. According to the Provisional Specification the machine may make tubes. |
