Abstract: An electromagnetic valve for use for discharge of molten metal from a container comprises a body (1) providing a discharge passage (2, 3) surrounded by an electrical induction coil (4), the passage having a first portion (2) adjacent the container having a radius greater than that of a second portion (3) extending from the first portion to the discharge end of the passage, whereby the frequency of the electric current supplied to the coil (4) can be chosen independently of the passage discharge diameter.

Abstract: An electromagnetic valve for use for discharge of molten metal from a container, comprises a main body providing a discharge passage through which, in use, molten metal will flow; and electrical induction coil located about the passage; means to supply an alternating electric current to the coil whereby the coil provides an alternating magnetic field which induces electric currents in any molten metal in the passage; and a center member located in the passage, the arrangement being such that interaction between the magnetic field provided by the coil and the currents induced in the molten metal in the passage provides a force which as it is increased causes the flow rate of the molten metal through the valve to be reduced until the force is sufficient to urge the molten metal away from the wall of the passage until the molten metal is supported on the center member and the flow of molten metal is cut off.

Abstract: The invention relates to channel induction furnaces employed for melting metals.A channel is arranged to extend downwardly from a bath and to form a loop whereby molten metal in the bath can pass into the looped channel to form a closed electrically conducting loop. A laminated iron core passes through a coil and forms a closed magnetic circuit linked with the coil and channel. Consequently, alternating current applied to the coil induces currents to flow in the molten metal in the channel, which metal is therefore heated. The molten metal is contained in the channel within a refractory lined vessel. With application of the alternating current to the coil electromagnetic forces are produced which are directed away from the walls of a channel. Thus a squeezing action is applied to the metal which produces an increase in static pressure towards the center of the channel relative to that at the wall. This pressure fluctuates from zero to a maximum value at twice the frequency of the induced current.