Patent ID: 8152131

Claim:
A wafer-shaped pilot-type valve that uses a pilot valve to control a driving force required for actuating a main valve to open and close the main valve, comprising: a valve box enclosing said main valve, said valve box being sandwiched between pipe flanges tightened to each other with bolts and nuts, a pair of said bolts being disposed in adjacent but circumferentially spaced-apart relationship with one another to define an interval therebetween, said valve box being flangeless at its connection end portions for connection with said pipe flanges and having an inlet and an outlet for a pressurized fluid; and a cover flange neck extended upward from said valve box, said cover flange neck defining a space for allowing passage of a pressurized fluid therethrough and only a valve stem passes through said space along with the pressurized fluid, said valve stem coupling said main valve with a driving portion for controlling the opening of said main valve in accordance with a variation in pressure fed from said pilot valve, wherein said cover flange neck has side walls and is constricted only at sites on the respective side walls disposed immediately adjacent said bolts of said pair of bolts so as to have a first width smaller than the interval between said bolts which interval will differ depending on a kind of said pipe flanges selected in accordance with a size of said valve so that said cover flange neck can be passed through the interval between said bolts of said pair of bolts extended between said pipe flanges and located adjacent to each other along circumferences of said pipe flanges, said cover flange neck having a second width defined in a direction parallel to a direction in which said bolts extend between the pipe flanges, the second width being greater than the first width.