n.预热器
The filament drive included a trailing weight and a preheater. 长丝体的传动部分包括一个拖拉重锤和一个预热器。
By analyzing the failure cause of boiler air preheater, the measure of preventing it from failure was discussed. 摘要通过对锅炉空气预热器失效原因的分析，提出了一些防止空气预热器失效的技术措施。
