Structural system:1) The concrete made of special composite steel plate does not pollute the magnesium liquid, has anti-corrosion structure inside, and has long service life.2) 1.2888 material manufacturing material pot and other spare parts, long service life3) Using a radiant tube or other heating method, the heater can be quickly replaced4) Stainless steel casing and panel, corrosion resistant, high temperature resistant5) Imported thermocouple, accurate temperature control and high service life6) Temperature control static ± 1 ° C, dynamic ± 3 ° C7) Preheater adopts clamping mechanism to make liquid level control stable and accurate feeding (patent: ZL201420137471.2)8) Preheating machine has low energy consumption and good preheating effect