US Patent 7481412 Solenoid-operated cutoff valve for use with fuel cells

A solenoid-operated cutoff valve for use with fuel cells has a movable member disposed in a guide housing for displacement upon energization of a solenoid. When the movable member is displaced, a pilot valve is unseated from a pilot valve seat. A fluid in a communication chamber flows through a pilot passage into an output port. The communication chamber is divided into a first communication chamber and a second communication chamber by a diaphragm. Under a pressure difference developed between the first communication chamber and the second communication chamber, a main valve of a valve head is unseated from a valve seat of a valve housing, opening the solenoid-operated cutoff valve.