| 摘要 |
PURPOSE:To prevent reverse flow of foul water by providing a reverse flow preventive chamber switching valve closing when passing water pressure is applied to a reverse flow preventive chamber and opening when it is eliminated among the atmosphere connection port of a branch water passage, a water storage hopper and the chamber. CONSTITUTION:A branch water passage 8 branched from a reverse flow preventive chamber 5 and connected to the suction side of a circulation pump 7 of a circulating circuit 2 is formed, and a water storage hopper 9 capable of storing water in the chamber 5, and an atmosphere connection port 10 for connecting the hopper 9 and the passage 8 to the atmosphere are provided. A reverse flow preventive chamber switching valve 11 closing when passing water pressure is applied to the chamber 5 and opening when it is eliminated is provided among the port 10 of the passage 8, the hopper 9 and the chamber 5, and a drain switching valve 12 is provided at the drain side of the hopper 9 of the passage 8. Thus, even if the valve is defective, it can prevent foul water from reversely flowing to the upstream side. |
