纵观国内外电磁阀，到目前为止，从动作方式上可分为三大类即：直动式、反冲式、先导式，而从阀瓣结构和材料上的不同以及原理上的区别反冲式又可分为：膜片式反冲电磁阀、活塞式反冲电磁阀；先导式又可分为：先导式膜片电磁阀、先导式活塞电磁阀；从阀座及密封材料上分又可分为：软密封电磁阀、钢性密封电磁阀、半钢性密封电磁阀。
1、直动式电磁阀
原理：常闭型直动式电磁阀通电时，电磁线圈产生电磁吸力把阀芯提起，使关闭件离远开阀座密封副打开；断电时，电磁力消失，靠弹簧力把关闭元件压在阀座上阀门关闭。（常开型与此相反）
特点：在真空、负压、零压差时能正常工作，DN50以下可任意安装，但电磁头体积较大。如我公司引进HERION公司技术生产的直动电磁阀可用于1.33×10-4 Mpa真空。
2、分步直动电磁阀
原理：它的原理是一种直动和先导相结合，通电时，电磁阀先将辅阀打开，主阀下腔压力大于上腔压力而利用压差及电磁阀的同时作用把阀门开启；断电时，辅阀利用弹簧力或介质压力推动关闭件，向下移动便阀门关闭。
特点：在零压差或高压时也能可靠工作，但功率及体积较大，要求竖直安装。
3、先导式电磁阀
原理：通电时，电磁力驱动先导阀打开先导阀，主阀上腔压力迅速下降，在主阀上下腔内形成压差，依靠介质压力推动主阀关闭件上移，阀门开启；断电时，弹簧力把先导阀关闭，入口介质压力通过先导孔迅速进入主阀上腔在上腔内形成压差，从而使主阀关闭。
特点：体积小，功率低，但介质压差范围受限，必须满足压差条件。
The electromagnetic valve, so far, from the way of action can be divided into three categories: direct acting, recoil, pilot type, and the difference from the recoil valve structure and different materials, the principle can be divided into: diaphragm type electromagnetic valve, piston recoil recoil power magnetic valve; pilot type can be divided into: the leading diaphragm solenoid valve, pilot type solenoid valve piston; from the valve seat and the sealing material points can be divided into: soft sealing solenoid valve, solenoid valve, steel seal semi steel sealing electromagnetic valve.
1, direct acting solenoid valve
Principle: normally closed type direct acting solenoid valve is energized, the electromagnetic coil of electromagnetic force to close off the valve lift, away from the valve seat sealing side open; power, the electromagnetic force disappears, by the spring force to close the pressure to close the valve on the valve element. (normally open)
Features: in the vacuum, negative pressure, zero pressure difference can work normally, DN50 can be installed at any time, but the larger electromagnetic head. Such as the introduction of our company HERION technology production of direct acting solenoid valve can be used for 1.33 x 10-4 Mpa vacuum.
2, step by step solenoid valve
Principle: it is the principle of a direct acting and pilot combination, energized, solenoid valve to open the auxiliary valve, main valve chamber pressure is greater than the chamber pressure and the pressure difference and the electromagnetic valve and the valve open; power, the auxiliary valve with a spring or to medium pressure to promote the closure of parts. Then close the valve to move downward.
Features: zero pressure or high pressure can also work reliably, but the power and volume of large, vertical installation requirements.
3, pilot solenoid valve
Principle: power, the electromagnetic force to drive the pilot valve to open the pilot valve, main valve cavity pressure decreases rapidly, the formation of pressure on the main valve cavity, rely on medium pressure to promote the closure of parts of the main valve moves up, valve opening; power, the spring force of the pilot valve closed, medium pressure entrance main valve cavity the pressure in the upper chamber quickly enters through the pilot hole, so that the main valve closed.
Features: small size, low power, but the medium pressure range is limited, must meet the pressure differential conditions.