direct-fired coil furnace

例句：

1. 1. This direct-fired coil furnace is used for melting metals.
   这种直接燃烧的线圈炉用于熔化金属。
2. 2.The manufacturer of the direct-fired coil furnace has been praised for its efficiency.
   这种直接燃烧的线圈炉的制造商因其效率而受到赞扬。
3. 3.The direct-fired coil furnace is an important tool in the manufacturing process.
   这种直接燃烧的线圈炉是生产过程中的一个重要工具。