Solenoid valves are electromechanically operated on/off devices used to control the flow of fluids. A valve plug is held in place by a spring. When the solenoid is energized, the current moves through the coil generating an electromagnetic force that opposes the spring, causing the plug to change position. When the power is switched off, the spring returns the plug to its former position. Some solenoid valves require differential pressure and must be designed to handle the demanding applications of industrial process control. As a worldwide leader in the design and manufacture of solenoid valves, ASCO Valves offer fast and safe switching, high reliability, long service life, low control power and compact design.