| 摘要 |
PURPOSE: A sewer backflow preventive device is provided to automatically prevent the backflow of sewer by pushing and closing a door with the flow of water using the principle of heart valves. CONSTITUTION: A sewer backflow preventive device comprises a door (10), a support shaft (11), a rubber packing (12), and a main shaft (20). The door is open to allow water to flow down to a drain in case of rain. Water is filled up from the bottom to close the door by allowing the water to flow backward when the amount of water increases. The backflow water is prevented by preventing the door from being open unless the amount of water flowing to the bottom is greater than the amount of water filled up from the bottom or a pressing force becomes stronger. |
