| 摘要 |
PROBLEM TO BE SOLVED: To provide a valve element of a diaphragm valve capable of responding even to a very low differential pressure of liquid, and capable of surely inhibiting the liquid from flowing back by preventing closing failure of a flow passage.SOLUTION: Valve elements 31 and 32 of this invention are valve elements of diaphragm valves 3 and 4 allowing fluid to pass through only in a prescribed direction in a flow passage, and include outer peripheral portions 35 and 36 compressed in the thickness direction and held by valve boxes 41 and 42 of diaphragm valves 3 and 4, center portions 33 and 34 having seating parts 33a and 34a elastically deformed in the thickness direction in response to a differential pressure of the fluid so that one surface side is put in close contact or in separation with/from valve seats 61 and 62 of the valve boxes 41 and 42, and intermediate portions 37 and 38 disposed between the outer peripheral portions 35 and 36 and the center portions 33 and 34 and having holes 39 and 40 through which the fluid can pass. A cross sectional shape of the intermediate portions 37 and 38 when being cut with a plane parallel to the radial direction and parallel to the thickness direction is formed to have at least one curved portion (or bent portion) 37a, 38a. |
