| 摘要 |
751,706. Induction heating. HERBERT, Ltd., A. Oct; 29, 1954, No. 31263/54. Class 39(3). A moulding machine for plasticising a thermoplastic or a thermosetting material, which is subsequently to be moulded, includes a heating cylinder 11 secured to a fitting 14 and covered by a refractory insulating layer 16 around which bare induction coils 17 and 18 are wound. Plastic material is supplied to the cylinder and is forced therefrom by a ram (not shown), through a nozzle 15 into a mould. During its travel the material is first heated by the coil 17 having a high heat output and then heated to a lesser extent by the coil 18. The coils are of naked nickel and are held in position by insulated metal bars 19 secured to the cylinder by screws extending between adjacent coil turns. An insulated spiral induction coil 23 heats the flange 12 of the cylinder to which one of its ends is secured and earthed by a plate 23a and screws 28. The flange is connected to a lead 27 of a transformer. The one ends of the coils 17 and 18 are earthed to the cylinder by connections 17a, 18a and the opposite ends of the coils 17 and 23 are connected to a common socket 31 connected to a transformer supply lead 32. The other end of the coil 18 is connected to a separate transformer tapping through a socket 34. Alternatively two transformers may be used, one supplying coils 17 and 23 and the other the coil 18. Thermocouples may control the treatment temperature by actuating switches which select the primary. transformer tappings. Lagging 36 surrounds the cylinder and coils. |
