PRESSURE CHAMBER TYPE VALVE

PROBLEM TO BE SOLVED: To discharge fluid in a pressure chamber by simple operation, to reduce size, and to reduce the number of part items by arranging a functional part for discharging the fluid in the pressure chamber to the secondary side by manual operation in a main valve element. SOLUTION: Since a pilot hole 4a is blocked up by valve seat packing 10, pressure of a pressure chamber 6 commnicated with a primary side passage 1 is kept under primary pressure by a bleeding hole 3b. A diaphragm valve element 5 is pressed to a seat surface 11a of a valve seat part 11 by differental pressure between this pressure chamber 6 and a secondary side passage 7, and the primary side passage 1 and the secondary side passage 7 are cut off to be put in a water stop state. When pulling up a plunger 9 and the valve seat packing 10 by carrying an electric current to a solenoid valve A, the pilot hole 4a is opened, and the pressure chamber 6 and the secondary side passage communicate with each other, so that pressure of the pressure chamber 6 suddenly drops. Thus, the diaphragm valve element 5 is pushed up in the direction for separating from the seat surface 11a, and the primary side passage 1 and the secondary side passage 7 communicate with each other to deliver water.