vacuum indicator

例句：

1. 1.The vacuum indicator on the vacuum cleaner showsthat the room is completely free of dust.
   吸尘器上的真空指示器显示房间完全无灰尘。
2. 2. The engineer used a vacuum indicatorto measure the air pressure in the chamber.
   工程师使用真空指示器测量腔室中的气压。
3. 3. The vacuum indicator was an essentialtool for detecting leaks in thepipeline system.
   真空指示器是检测管道系统中泄漏的关键工具。