| 摘要 |
PURPOSE: A preheater for metal material is provided to prevent the variation of preheating temperature, thereby improving a preheating efficiency without damage to the metal material. CONSTITUTION: A preheater for metal material includes a preheating case(110), a first sheath heater, a second sheath heater, a first thermocouple, a second thermocouple, and a controller. The preheating case on a roller(11) transferring the metal material(10) forms a preheating space. The first and the second preheater respectively preheat the upper and the lower side of the metal material. The first and the second thermocouple respectively detect the variations of preheating temperatures by the first and the second sheath heater. The controller receives the detecting signals of the first and the second thermocouple, and then separately turns on/off the first and the second sheath heater in order to identically maintain temperatures at the upper and the lower part inside the preheating case. |
