| 摘要 |
PURPOSE:To improve the transmission efficiency of the high-frequency electric power necessary for melting a casting material by inscribing spiral grooves meeting the winding direction and winding pitch of a high-frequency coil on the outside circumferential surface of a cylindrical refractory vessel to be wound with the high-frequency coil. CONSTITUTION:A titled device is provided successively with a melting part 4 consisting of winding a high-frequency coil 2 on the outside circumference of a cylindrical refractory vessel 3 contg. a crucible 5 and a casting mold part 12 consisting of a projecting casting mold 11 molded integrally with a sprue 8 and a casting mold 9 by an investing material 10. Sprial grooves 17 meeting the winding direction and winding pitch of the coil 2 of such device are inscribed to the part on the outside circumference of said vessel 3 to be wound with the coil 2. The coil 2 is thus approached to the body to be heated in the crucible 5 while the mechanical strength of the vessel 3 is thoroughly maintained by which the coefft. of coupling between both is increased. The transmission efficiency of the high-frequency electric power necessary for melting the casting material is thus improved. |
