draft retarder

例句：

1. 1. The engineer designed a draft retarder to improve the efficiency of the machinery.
   工程师设计了一个草案减速器来提高机器的效率。
2. 2. The draft retarder was used to slow down the flow of water in the pipeline.
   草案减速器被用来减缓管道中水流的速度。
3. 3.The draft retarder was installed at the beginning of the pipeline to prevent any potential problems during operation.
   在管道的起始处安装了草案减速器，以防止运行过程中可能出现的问题。