flat sealing ring

例句：

1. 1. The flat sealing ring is used to ensure the tightness of the joint.
   这个平密封环用来确保接头的紧密性。
2. 2. The flat sealing ring was designed to prevent leaks in the pipeline system.
   这个平密封环被设计来防止管道系统中的泄漏。
3. 3.The engineer carefully inspected the flat sealing ring before installing it.
   工程师在安装之前仔细检查了平密封环。