Abstract: A diaphragm valve having a diaphragm valve element including a valve element body movable into contact with a valve seat, a web portion extending outward from the valve element body, and a fixed portion formed at an outer peripheral edge of the web portion. The web portion includes a vertical portion vertically formed continuous with the valve element body, a horizontal portion horizontally formed continuous with the fixed portion, and a connecting portion of a circular arc shape (an upward protruding shape) in section to connect the vertical portion with the horizontal portion, thereby holding the vertical portion in constant contact with an outer surface of a backup.

Abstract: The present invention is made to prevent stress concentration on or around a boundary between a valve element body and a web portion of a diaphragm even in controlling supply of high-pressure fluid, thereby improving durability of the diaphragm. A diaphragm valve 1 of the present invention comprises a diaphragm valve element 20 including a valve element body 21 movable into contact with a valve seat 13, a web portion 22 extending outward from the valve element body 21, and a fixed portion 23 formed at an outer peripheral edge of the web portion 22. The web portion 22 includes a vertical portion 22a vertically formed continuous with the valve element body 21, a horizontal portion 22c horizontally formed continuous with the fixed portion 23, and a connecting portion 22b of a circular arc shape (an upward protruding shape) in section to connect the vertical portion 22a with the horizontal portion 22c, thereby holding the vertical portion 22a in constant contact with an outer surface of a backup 40.

Abstract: A chemical liquid control valve is provided with a barrier on an outer circumferential end portion of a protruding part (an outer circumferential bottom portion of a valve seat). The barrier is placed so that an angle between the center line of an outlet passage and the line extending between the center of a valve port and each end of the barrier. The barrier is designed to have a height relative to a contact surface of the valve seat with a valve element is substantially half of the travel distance of a diaphragm valve element.

Abstract: A chemical liquid control valve is provided with a barrier on an outer circumferential end portion of a protruding part (an outer circumferential bottom portion of a valve seat). The barrier is placed so that an angle between the center line of an outlet passage and the line extending between the center of a valve port and each end of the barrier. The barrier is designed to have a height relative to a contact surface of the valve seat with a valve element is substantially half of the travel distance of a diaphragm valve element.