A check valve suitable for drainage outlets in coastal areas, focusing on preventing backflow as a check device, which can effectively prevent

Rainstorm Backflow: Hidden Threat and Scientific and Technological Defense Line in Urban Low lying Areas

Today, with frequent extreme weather, urban waterlogging caused by rainstorm has become a global problem. The phenomenon of drainage system backflow has become a "hidden killer" threatening urban safety due to its suddenness and destructiveness. During the extremely heavy rainstorm in Zhengzhou in 2021, a tragic case of an underground garage being completely submerged within 30 minutes due to pipeline backflow reminds us that we must face up to this urban governance problem.

1、 Formation Mechanism and Harm of rainstorm Backflow

When the rainfall intensity exceeds the design standard of urban drainage system (usually once every 10 years), the rainwater pipe network is in an overloaded state. Low lying areas form a hydraulic "basin effect" due to the disadvantage of elevation, and the water level difference inside and outside the pipeline creates a reverse pressure gradient. At this point, if the drainage outlet is lower than the water level of the receiving water body, a backflow phenomenon will occur, similar to the "siphon effect" that pushes the external water body back into the pipeline system.

The domino effect caused by this phenomenon is shocking: during a typhoon, a rainwater inspection well in a coastal city spewed out a 2-meter-high water column due to backflow; Water ingress into the basement substation equipment has caused widespread power outages in the urban area; The pathogens carried by the backflow of sewage have caused a concentrated outbreak of gastrointestinal diseases in the community. Statistics show that the economic losses caused by pipeline backflow in China exceed 5 billion yuan annually.

2、 Technological breakthrough of anti backflow device

The medium-sized built-in anti backflow device adopts the principle of fluid dynamics to construct an intelligent barrier. The built-in anti backflow device is mainly based on the interaction of its internal components and the flow characteristics of water. When the internal water level is higher than the external water level, the membrane flap opens positively under a smaller head pressure, allowing the internal sewage to be discharged into the external sewage interception pipe normally. When the water level of the external sewage interception pipe gradually rises above the internal water level, the valve body will seal in reverse to prevent sewage from flowing back into the interior of the villa. In addition, the built-in anti backflow device also has the characteristics of reverse back pressure and self elasticity to achieve reliable sealing, which can maintain the sealing effect under high water head pressure.

The built-in rubber adopts a pulse principle design, reducing water head loss by 80%; The self-cleaning structure can effectively prevent garbage from getting stuck; The modular design enables it to adapt to pipe diameters of different materials ranging from 100-2400mm. After the installation of a renovation project in an old urban area of Guangzhou, the number of backflow accidents decreased by 92% under the same rainfall conditions.

3、 The construction of a systematic defense system

Establishing a three-dimensional defense network requires multidimensional collaboration: in terms of spatial layout, a three-level system of "source stagnation infiltration process control end interception" should be formed; In terms of facility configuration, the combination of intelligent diversion wells, regulating tanks, and backflow preventers is used; At the operational management level, build a water level warning system based on the Internet of Things.

The operation and maintenance strategy should follow the concept of "preventive maintenance": conduct sealing tests every quarter, use pipeline robots to clean up sediment, and complete hydraulic system calibration before the flood season. The Public Utilities Board of Singapore maintains the reliability of the drainage system at over 99.8% through regular drills and intelligent monitoring.

Faced with the challenges brought by climate change, urban flood control has entered the era of precise prevention and control. The innovation of anti backflow technology not only requires upgrading of engineering hardware, but also deep integration with intelligent technologies such as digital twins and AI prediction. When each drainage node has the ability to autonomously perceive and make decisions, our city can truly build a resilient defense line against extreme weather. Behind this technological evolution is the wisdom of harmonious coexistence between humans and nature.