| 摘要 |
431,333. Coiling. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Zabel, W. P. ; 2060, Hanover Road, Cleveland Heights, Ohio, U.S.A.) Dec. 29, 1933, No. 36612. Convention date, Dec. 31, 1932. [Class 83 (iv)] [See also Groups XI and II] In a method of making coiled-coil filaments a filament wire is wound around a primary mandrel which is considerably less refractory than the filament, and the coil with its mandrel is then wound around a refractory secondary mandrel, the coiled structure thus formed being then heated to nearly a white heat to remove a considerable part of the strains in the primary coil, after which the primary mandrel is removed and the coiled coil on the secondary mandrel heated to approximately 2800‹ C., the secondary mandrel being removed finally. After the removal of the primary mandrel the filament is heated to a red heat, then to 2250‹ C. in approximately fifteen seconds, and then to 2800‹ C. in approximately a further thirty seconds. In the example a tungsten wire is first coiled around a steel mandrel, this coil next being wound around a secondary mandrel 12, Fig. 3, of tungsten wire. As shown, the secondary coil comprises a series of spaced segments 13 with an extra long space between consecutive groups of segments, each group constituting a filament. The primary coil 10 is secured, preferably by welding, to the secondary mandrel 12 at two points 15, 16 about half an inch apart between two groups of segments 13, 14, the welds being of nickel or other metal which does not dissolve in hydrochloric acid or strong alkalies. After welding, the coil is heated to a white heat, or about 1100‹ C., in an electric furnace in the presence of hydrogen, the mandrel 12 being either passed through the furnace, or the individual groups being first separated by cutting the mandrel between the welds 15, 16 before placing them in the furnace. The steel mandrel is next dissolved out in a hydrochloric acid solution, and the ends of the coil and mandrel assembly are clipped within the jaws 18, 19, Fig. 4, of a fixed terminal clip 17 on a hollow tube 30, and similar jaws 20, 21 on a clip 20 adjustably mounted on a hollow tube 43. The clips and coil assembly are enclosed in a hydrogen bottle 53 which has its open end sealed by a compressed rubber tube 58 within an annular groove 57 in a mounting-plate 31, a water jacket 64 being provided around the bottle 53. Terminal clips 51, 52 are secured on the tubes 30, 43 which conduct current to the mandrel 12 and coil 10. The tubes 30, 43 are cooled by circulating water therethrough. To compensate for expansion and contraction of the mandrel 12 the clip 20 is supported on a pair of bolts 47 which are secured in a block 48 and pass through a block 49 clamped on the tube 43, with coil springs 50 surrounding the bolts between the blocks 48, 49. |
