Abstract: A diaphragm valve includes a first valve housing, a diaphragm, a drive member, and a second valve housing. The diaphragm has a second abutting surface opposed to a first abutting surface, and a sealing portion formed on a position surrounding a second abutting surface. The diaphragm has an elastic coupling portion that elastically deforms and couples the second abutting surface to the sealing portion to cause the second abutting surface to move to a side of the first valve housing with respect to the sealing portion. The elastic coupling portion has a concave curved surface having a curved surface shape that is concave to a side of the second valve housing. The second valve housing has a supporting portion having a second convex curved surface having a curved surface shape that is convex to a side of the elastic coupling portion on a position opposed to the concave curved surface.

Abstract: In a fluid control valve, a valve part houses a diaphragm in a valve body including a valve seat, first and second ports, and a drive part includes a piston dividing a piston chamber in a cylinder body into first and second chambers, and a rubber sealing member attached to the outer peripheral surface of the piston. A constriction is provided between the piston chamber and the surface of the cylinder body contacting the valve body. The cylinder body is formed with an exhaust port communicating with the first chamber, an operation port communicating with the second chamber, and a purge port communicating with a fluid non-contact chamber. The piston is formed with a flow path which enables communication between the first chamber and the fluid non-contact chamber. Accordingly, a temperature increase of the drive part can be restricted, and degradation of internal parts can be prevented.

Abstract: In a fluid control valve, a valve part houses a diaphragm in a valve body including a valve seat, first and second ports, and a drive part includes a piston dividing a piston chamber in a cylinder body into first and second chambers, and a rubber sealing member attached to the outer peripheral surface of the piston. A constriction is provided between the piston chamber and the surface of the cylinder body contacting the valve body. The cylinder body is formed with an exhaust port communicating with the first chamber, an operation port communicating with the second chamber, and a purge port communicating with a fluid non-contact chamber. The piston is formed with a flow path which enables communication between the first chamber and the fluid non-contact chamber. Accordingly, a temperature increase of the drive part can be restricted, and degradation of internal parts can be prevented.

Abstract: A flow control valve is provided in a manner to be capable of locking a position of a differential screw easily without displacing a position adjusted valve element body. The valve element body is brought into or out of contact with a valve seat provided between a first port and a second port, and is connected to an operation member. The operation member is movably inserted into a cover and urged to a direction toward the valve seat by an urging member. A position of the operation member is adjusted by a differential screw, and accordingly a position of the valve seat is adjusted. A rotation member for exerting a rotation force on the differential screw is slidably mounted in the cover along a moving direction of the operation member without rotating. A locking portion is provided in the rotation member to engage with the cover without rotating when the operation member is slid along its moving direction.

Abstract: A flow control valve is provided in a manner to be capable of locking a position of a differential screw easily without displacing a position adjusted valve element body. The valve element body is brought into or out of contact with a valve seat provided between a first port and a second port, and is connected to an operation member. The operation member is movably inserted into a cover and urged to a direction toward the valve seat by an urging member. A position of the operation member is adjusted by a differential screw, and accordingly a position of the valve seat is adjusted. A rotation member for exerting a rotation force on the differential screw is slidably mounted in the cover along a moving direction of the operation member without rotating. A locking portion is provided in the rotation member to engage with the cover without rotating when the operation member is slid along its moving direction.