valve closure

例句：

1. 1. The valve was closed to prevent the leakage.
   为了防止泄漏，阀门被关闭了。
2. 2.The valve is used to control the flow of gases.
   阀门用于控制气体的流动。
3. 3. The valve closure system ensures that the valve remains open until it is manually opened.
   阀门关闭系统确保阀门在手动打开之前保持开启状态。