| 摘要 |
810,710. Electric heating resistor. METALS & CONTROLS CORPORATION. April 12, 1957 [May 21, 1956], No. 12075/57. Class 39(3) [Also in Group XXXVI] A heating resistor 10 preferably a coiled rod is of metal is welded at 15 to a terminal plate 13 of a different metal, and all the exposed surfaces of the resistor is uniformly oxidized while at least a part of the terminal plate is non-oxidized. The resistor may be an alloy comprising 60 per cent of nickel, 16 per cent of chronium, the remainder being iron or 35 per cent of nickel, 18.5 per cent of chrominal and the remaiinder iron. The terminal plates 13 may be of nickel or "Monel" (Registered Trade Mark) or an alloy of 60 per cent nickel and the remainder copper and may have bonded to its lower surface a contact plate of a precious metal e.g. silver, the exposed surface of which is non-oxidized. The bonded assembly is heated in a gas which uniformly oxidizes the resistor but leaves the terminal unoxidized e.g. cracked city gas comprising 5-7 per cent carbon monoxide, 2 per cent carbon dioxide, 5-7 per cent hydrogen the remainder being water vapour. At 1550-1600‹F. the gas acts as oxidizing atmosphere for the resistor but as a reducing atmosphere for the terminal. U.S.A. Specification 2,501,156 is referred to. |
