main relay valve

例句：

1. 1. The main relay valve is responsible for controlling the flow of electricity in the circuit.
   主继电器阀负责控制电路中电流的流动。
2. 2.Main relay valves are used to control the flow of gases and liquids in industrial processes.
   主继电器阀用于控制工业过程中气体和液体的流量。
3. 3.The main relay valve was replaced due to a faulty connection that caused a power outage.
   由于连接故障导致停电，主继电器阀被更换。