| 摘要 |
PURPOSE:To perform automatic emergency interruption and recovery of flow path reliably by forming permanent magnet rings for holding a ball valve seat while surrounding the outside of valve seat slidably in axial direction. CONSTITUTION:A ball valve body 5 made of ferromagnetic material is contained idly in a valve chamber 11 and normally energized toward upstream side through a resilient member 6. Upon current flow through an electromagnetic circuit 10 under abnormal state, magnetic field is formed in the electromagnetic coil 9 to move the ball valve body 5 toward the valve seat 12 and to hold in a valve seat through attraction of permanent magnet 7 while pressure contacting. In order to recover to such state as to flow the fluid again upon termination of abnormal state, the permanent magnet 7 is slided to the downstream side. Here, the ball valve body 5 is separated from the valve seat 12 through said resilient member 6 and left idling on the bottom of valve chamber 11 thus to flow the fluid. |
