| 摘要 |
PURPOSE:To prevent the liquid at the incoming pipe side from mixing with that at the valve chest side even in the event of leakage owing to intrusion of foreign matters by furnishing internal and external valve elements and an opening/ closing member solidly as in a single body at the inside edge of the valve stem. CONSTITUTION:When the valve stem 11 proceeds, the external and internal valve elements 12, 13 are placed on the external and internal valve seats 9, 10 and, at the same time, the returning part 14 retracts the opening/closing member 7 against the force applied by a repulsive machine 8, and the incoming pipe 2 is then put in closed position. If a leakage happens at this time owing to imperfect closing of the external or internal valve element 12, 13 caused by intrusion of foreign matters between the external valve element 12 and valve seat 9 or between the internal valve element 13 and valve seat 10, the leak liquid from the external valve element 12 flows down at the outside surface of the returning part 14 and opening/closing part 7 while the leak liquid from the internal valve element 13, at the inside surfaces of the returning part 14 and opening/closing member 7 individually to be exhausted from a drainage hole 4. |
