進口蒸汽電磁閥是由副閥和主閥兩大部件構成的先導式二次開閥的電磁閥。是靠副閥的啟閉來控制主閥的通斷。根據斷電時所處開關狀態的不同，可分為常閉電磁閥和常開電磁閥。
Steam electromagnetic valve is made by the Deputy valve and main valve consisting of two parts guide type two opening valve electromagnetic valve. On the side the valves open and close to the main control valve on-off. According to the power which the switch state is different, can be divided into normally closed solenoid valve and the normally open solenoid
進口蒸汽常閉電磁閥在斷電常位時，副閥口封閉，主閥呈斷路，當電訊號進入導閥線圈時，活動鐵芯受電磁力作用吸上打開副閥口，主閥閥杯內壓力迅速消失，介質壓力將主閥閥杯托上，開啟主閥口，工作介質硬可流通。但當電訊號消失時，活動鐵芯復位，封閉住副閥口，工作介質自平衡孔進入閥杯內，當壓力趨于平衡時，靠主閥彈簧、閥杯自重及介質壓力使閥杯下移，嚴密封住主閥口，閥又呈關閉狀態。
Inlet steam normally closed solenoid valve in power often position, vice valve closed, the main valve is open, when the electrical signal into the pilot valve coil, core activities by electromagnetic force sucking on open side valve, the main valve pressure in the cup quickly disappeared, medium pressure of the main valve cup holder, open the main valve port, the working medium hard negotiable. But when the signal disappears, the movable iron core reset, vice valve closed, the working medium self balancing hole into the valve cup, when the pressure is balanced, rely on the main valve spring, valve cup weight and medium pressure causes the valve cup downward, tight seal main valve port, valve was closed.
進口蒸汽常開電磁閥在斷電常位時，由彈簧作用，副閥口打開，主閥流通。當電訊號進入副閥線圈時，活動鐵芯受電磁作用吸下，副閥口封閉，工作介質經平衡孔進入閥杯內，當壓力趨于平衡時，靠主閥彈簧、閥杯自重及介質壓力使閥杯下移，嚴密封主閥口，閥門呈關閉狀態。當主閥斷電時，電磁力消失，副閥打開，主閥杯內壓力迅速消失，介質壓力將主閥閥杯托上，開啟主閥口，介質流通，閥呈開啟狀態。
Steam electromagnetic valve in power down often when, by spring action, the Deputy valve port opened, the main valve flow. When the signal into the auxiliary valve coil, core activities by electromagnetism suction, vice valve closed, working medium through the balance hole into the valve cup, when the pressure is balanced, rely on the main valve spring, valve cup weight and medium pressure causes the valve cup downward, tightly sealed and the main valve port, valve is closed state. When the main valve is powered off, the electromagnetic force disappears, the Deputy valve is opened, the main valve pressure in the cup quickly disappeared, medium pressure of the main valve cup holder, open the main valve port, medium circulation, valve is in an open state.
