GB446322A - Improvements in or relating to extrusion presses with electrically heated receivers for the production of metallic tubes and rods - Google Patents

Abstract

446,322. Heating by electric induction. TRIGGS, W. W., 57. Lincoln's Inn Fields, London.-(Schloemann Akt.-Ges. ; 13, Steinstrasse, D³sseldorf, Germany) Sept. 13, 1935, No. 25436. [Class 39 (iii)] The receiver of a press for the extrusion of metal is heated by eddy currents induced by current of ordinary mains frequency, such as 50 cycles per second, flowing in a coil arranged coaxially with the bore. A receiver comprises sleeves 1, 2, Fig. 1, of steel having a high permeability, which are assembled by shrinking, a casing 5 providing a space for the heating coil 4. The coil comprises two coaxial layers of flattened copper tubes, separated by bars 6 with a mica coating. Distance pieces of asbestos slate are notched to engage the bars 6, and metallic segments engage further notches in the distance pieces and space turns of the two layers at the same level. The layers are arranged in parallel electrically, the inlet and outlet for cooling water being at the same potential so that they may both be earthed. In a modification, the casing is prevented from heating by laminated magnetic material and a conducting sleeve between the coil and casing. In a further modification, the heating coil comprises rods 22, Fig. 4, in the body of the receiver, the end connections being embedded in grooves 24. Copper tubes 4 may be coated with chromium to reflect heat from the surrounding members.