When the coil is not energized the spring works on the disc keeping the gas passage closed. When the coil is powered the valve opens. When power is switched off the valve rapidly shuts.
Extra options: 1900.0020 = Ex-proof, explosion proof version 1900.0029 = IP65 enclosure rating 1900.0040 = IP65 with 1 meter cable 1900.0060 = IP65 with 1,5 meter cable