envelope kiln

例句：

1. 1. The envelope kiln is used for the processing of paper products.
   信封窑用于纸制品的加工。
2. 2. The envelope kiln is an important tool for the production of paper and cardboard.
   信封窑是生产纸张和纸板的重要工具。
3. 3. The envelope kiln is a machine that uses heat to fuse together materials.
   信封窑是一种使用热能将材料粘合在一起的机器。