Abstract: An annular exhaust gas passage 2 and an airtight retention member 3 for keeping the inside of a crucible induction furnace 1 airtight are installed on the top of the furnace 1, and an exhaust system under atmospheric pressure is connected to a valve 4 via an air duct that penetrates the airtight retention member 3. In addition, a sealing cover 7 that has a valve 8, which can be opened and closed, is used to keep the inside of the furnace airtight, while a system under reduced pressure is connected to the valve 8. These two systems constitute the entire exhaust system.

Abstract: A furnace in the invention includes an induction melting furnace housed in an air-tight container which can be pressurized to the desired level of maximum allowable pressure and can be vacuum evacuated to a desired level of pressure; a vacuum melting furnace cover having a vacuum evacuating pipe; and a pressure pouring furnace cover, which has a pressure piping to impress the pouring pressure controlled by a pouring pressure control device onto the inside of the furnace and has a pouring siphon, which has its lower end opened to the bottom part within the induction melting furnace and has its upper end connected to a pouring chamber having a pouring nozzle, penetrated therethrough.

Abstract: In a fast-melting induction furnace, an elevationally movable pressing cover 4 suppresses the swell of molten metal 3 inside a crucible 2 on which a coil 1 is wound. The pressing cover 4 has a lower surface which is made concave. An upper half part of the motion of the molten metal 3 caused by electromagnetic force is made in conformity with the concave shape of the lower surface 5, so that the dangerous blowout of molten metal through a gap 8 is effectively prevented. Accordingly, the fast melting by the supply of high electric power can be performed. The lower surface 5 may be shaped as a cylindrical surface, a paraboloidal surface of revolution, a partial spherical surface, or the like, or may be shaped like a runner bucket of a Pelton turbine which has a slightly projecting center portion.

Abstract: A crucible induction furnace is disclosed which is provided with a preventive measure against low melting point metals and having a crucible refractory within an induction coil in a barrel container, in which the crucible induction furnace comprises a coil protection member located between the crucible refractory and the induction coil and which includes at least one air-permeating portion. An air supply pipe is in communication with the air-permeating portion for supplying pressurized air to the crucible refractory. The air permeating portion is disposed to distribute pressurized air having a higher pressure adjacent to the bottom portion of the crucible refractory than to the upper portion of the crucible refractory.

Abstract: An apparatus for heating molten metal including a ladle provided with a refractory heat insulating material and first core members arranged in pairs and attached to the outer circumference of the ladle. A tray capable of mounting said ladle carries second cores with magnetic pole portions at both ends of said cores as to face the ladle mounted first cores. A coil is provided for exciting the second cores. The first cores and magnetic pole portions of second cores are located at the outer circumferential portion of the ladle to face each other radially in a manner to facilitate placement and removal of the ladle to and from the tray. Position sensors are provided to ensure positional accuracy of the first ladle carried cores and the poles of the second cores. The coils are physically and thermally protected from ladle heat by appropriate shock absorbing and thermal insulating provisions. Thermal protection of the cores can be further enhanced by cooling embodiments.

Abstract: An apparatus for heating molten metal including a ladle provided with a refractory heat insulating material and first core members arranged in pairs and attached to the outside of the ladle. A tray capable of mounting said ladle carries second cores with magnetic pole portions at both ends of said so as to face the ladle mounted first cores. A coil if provided for exciting the second cores. The first cores and magnetic pole portions of second cores are located at the outer circumferential portion of the ladle to face each other radially in a manner to facilitate placement and removal of the ladle to and from the tray. Position sensors and means are provided to ensure positional accuracy of the first ladle carried cores and the poles of the second cores. Also the coil are physically and thermally protected from ladle heat by appropriate shock absorbing and thermal insulating provisions. Thermal protection of the cores further enhanced by cooling embodiments.

Abstract: A method is provided for manufacturing a clad tube comprising a metallic tube coated on the interior surface with a thermally deformable coating material, comprising:(a) coaxially positioning the metallic tube within a cylindrically formed induction coil;(b) coaxially positioning a tube of the coating material within the metallic tube;(c) applying a current to the induction coil such that the induction coil serves as a heater and heats the metallic tube which in turn radiantly heats the tube of coating material to a temperature sufficient to make the coating material deformable; and(d) applying pressure on the interior of the tube of coating material such that the softened tube of coating material deforms to contact and fuse with the interior surface of the metallic tube to form a clad tube. The coating material can be, for example, glass or a thermally deformable resin. Optionally, a magnetic tube can be inserted into the interior of the tube of coating material.

Abstract: An induction furnace in which a graphite crucible is encompassed by a spaced thermal insulating sheath. The annular space therebetween is sealed and a coil is circumferentially mounted about the sheath. The crucible thus constructed is placed on a furnace bed which is provided with a conduit for discharging the molten metal therein.