direct-seal valve

例句：

1. 1.The new direct-seal valve has greatly improved the efficiency of the system.
   新型直接密封阀大大提高了系统的工作效率。
2. 2. The engineer carefully inspected the direct-seal valve before installing it.
   工程师在安装之前仔细检查了直接密封阀。
3. 3. The valve was designed to prevent leaks and ensure safe operation of the machinery.
   该阀门设计用来防止泄漏，确保机器的安全运行。