To obtain a 2-port vacuum valve having improved functionality that can freely adjust a valve opening according to usage conditions or the like.
First and second pistons 15 and 32 are accommodated in a piston chamber 2a in a cylinder 2. The first piston 15 is linked to a main valve member 14 for opening/closing a main channel 6. The second piston 32 is linked to a second rod 42 having a stopper 43 whose position can be freely adjusted. Pressure fluid is supplied to a second pressure chamber 40 for allowing the second piston 32 to advance to a position where the stopper 43 comes into contact with a contacting section 39b. In that state, the pressure fluid is supplied to a first pressure chamber 29 for stroking the first piston 15 to a position for coming into contact with the second piston 32, thus opening the valve of a main valve member 14 by stroke X in the first piston 15.
Masahiko Goto
Hayashi Naoki