Controlled magnesium melt process, system and components therefor

摘要

Apparatus for a fully automated magnesium melt system. Raw magnesium ingots are moved through and controllably heated in a preheater chamber before they are introduced into a melt cell. A probe monitors the metal level and a control unit causes ingot charging as determined by a process level set point or temperature overshoot. There are two zones of heating in the melt cell with each zone supplied by its own 3 phase zero cross fired silicon controlled rectifier and firing board which is gated by a gating signal. This controls how much the SCR's are allowed to conduct. The amount of error between the metal bath set point and the actual metal bath temperature automatically determines how much of the 4-20 mA gating signal is required to maintain the set metal bath temperature. Liquid magnesium is transferred from the melt cell to a die cast machine by a siphon transfer tube which has two sets of electrical heating elements. A programmable logic controller, with suitable programming, controls the temperature at all times of the molten magnesium and preheating of the ingots. This PLC and other monitoring or remotely located computers provide complete process control and information.