Patent ID: 7806136

Claim:
A wafer-type direct-acting valve comprising: a driving section operating when it senses a primary pressure or a secondary pressure of a pressure fluid; a valve body communicating with the driving section to open and close a flow path through which the pressure fluid can pass; and a valve box which defines the flow path and is sandwiched between pipe flanges which are tightened together by bolts extending between said pipe flanges and nuts, connecting end portions of the valve box having an inlet and an outlet into and from the flow path respectively which permit said pressure fluid to flow therethrough, which said connecting end portions are respectively positioned in cooperation with said pipe flanges, each of the connecting end portions being formed to have a smaller diameter than that of the pipe flange in cooperation therewith, wherein the valve box further includes a cover flange neck extending upward from the valve box and having opposite side walls which define a space through which the pressure fluid can pass and which only receives a valve bar extending through said space connecting the driving section to the valve body, said side walls being disposed directly adjacent to corresponding ones of said bolts, and the side walls of the cover flange neck corresponding to the respective adjacent bolts are constricted in such a manner to define a narrow neck dimension of said cover flange neck that is narrower than a bolt interval between the adjacent bolts, wherein the bolt interval varies depending on the kind of pipe flanges being used in accordance with the size of the valve and the narrow neck dimension is formed such that the cover flange neck can be interposed between the bolts located between the pipe flanges in accordance with the bolt interval, which said bolts are adjacent to each other on a circumference of the pipe flanges, and wherein said cover flange neck has a wide neck dimension defined in a direction parallel to a direction in which the bolts extend between the pipe flanges, the wide neck dimension being greater than the narrow neck dimension.