原理：它是一种直动和先导式相结合的原理，当入口与出口没有压差时，通电后，电磁力直接把先导小阀和主阀关闭件依次向上提起，阀门打开。当入口与出口达到启动压差时，通电后，电磁力先导小阀，主阀下腔压力上升，上腔压力下降，从而利用压差把主阀向上推开；断电时，先导阀利用弹簧力或介质压力推动关闭件，向下移动，使阀门关闭。
特点：在零压差或真空、高压时亦能可*动作，但功率较大，要求必须水平安装。
Z2S10A1-20B/ Z2S10A2-20B/ Z2S10A3-20B/
Z2S10B1-20B/ Z2S10B2-20B/ Z2S10B3-20B/
Z2S10-1-30B/ Z2S10-3-30B/ Z2S10A1-30B/ Z2S10A3-30B/
Z2S10B1-30B/ Z2S10B3-30B/
4WE10F31B/CG24N9Z5L 4WE10F31B/CW220-50N9Z5L
4WE10G31B/CG24N9Z5L 4WE10G31B/CW220-50N9Z5L
4WE10H31B/CG24N9Z5L 4WE10H31B/CW220-50N9Z5L
M-4SEW6D30B/420MG24N9K4 M-4SEW6D30B/630MG24N9K4
M-4SEW6Y30B/420MG24N9K4 M-4SEW6Y30B/630MG24N9K4
DB3U10H-1-30B/100W220-50NZ5L DB3U10H-1-30B/100G24NZ5L
DB3U10H-1-30B/315W220-50NZ5L DB3U10H-1-30B/315G24NZ5L
DB3U10H-2-30B/100W220-50NZ5L DB3U10H-2-30B/100G24NZ5L
HED4OH15B/50Z14L24S HED4OH15B/100Z14L24S HED4OH15B/350Z14L24S
HED4OH15B/50Z14L110S HED4OH15B/100Z14L110S HED4OH15B/350Z14L110S
HED4OH15B/50Z14L220S HED4OH15B/100Z14L220S HED4OH15B/350Z14L220S