Use of internal heating to ensure the heating tube working without air oxidation, thus to lengthen the service life of heating element. PID intelligent control and precious metal sensor to timely show the temperature in the furnace, thus to actuate precise temperature control. Use of high quality stainless steel tin pot to feature high temperature resistance, quick temperature rise, long service life, economy of electric power and easy operation. Technical parameter: Type: ZB1510D, ZB2015D, ZB2520D, ZB3025D, ZB3530D Range of Temperature control: Normal temperature~500+-1% Dimension of tin trough: 150*00*70mm, 200*150*70mm, 250*200*70mm, 300*250*70mm, 350*300*70mm Weight of tin: 7.5Kg, 15Kg 25Kg 38Kg 53Kg Power: 700W, 1000W, 1400W, 1700W, 2100W Power supply: AC220V+-10%50Hz Dimension: 370*160*140mm, 420*210*140mm, 470*260*140mm, 520*310*140mm, 520*410*140mm