empty and load changeover cock

例句：

1. 1. The engineer needs to change the empty and load changeover cock to ensure smooth operation of the machine.
   工程师需要更换空载转换开关，以确保机器的顺畅运行。
2. 2. During maintenance, the technician found that the empty and load changeover cock was faulty and needed replacement.
   在维护过程中，技术人员发现空载转换开关有故障，需要更换。
3. 3.The old factory had a large number of empty and load changeover cocks, which were used for various industrial processes.
   旧工厂拥有大量的空载转换开关，用于各种工业过程。