Backflow Preventer Valve

Backflow preventer valve is a dedicated safety pipeline device that stops contaminated, unclean medium from flowing backward into clean water supply systems. Unlike ordinary check valves that only block general reverse flow, this product meets strict cross-contamination protection codes and provides dual-stage anti-backflow protection for drinking water and municipal water supply networks.

Its internal structure usually contains two independent one-way check assemblies plus a relief discharge zone between them. When water flows normally in the forward direction, water pressure pushes both internal check discs open to maintain smooth water delivery. If downstream pressure rises higher than upstream pressure due to water cut-off, pipeline pressure fluctuation or pump shutdown, the first downstream check will close rapidly. If tiny leakage occurs on the first sealing unit, the intermediate pressure chamber will trigger the relief port to drain excess pressure, while the second upstream check valve forms a second safety barrier to completely isolate polluted downstream fluid from clean upstream drinking water. This double-block and discharge design achieves a higher safety level than single check valves.

Most backflow preventers are constructed with ductile iron or stainless steel bodies, fitted with food-grade EPDM rubber seals that comply with drinking water contact standards. Standard connection types include flange, threaded and grooved ends to fit building domestic water, fire water and municipal pipeline construction. The whole device is factory pressure-tested to guarantee zero cross-contamination risk under rated working pressure PN10 and PN16.

Ordinary single check valves can only resist simple backflow caused by static water pressure, but they cannot prevent back-siphonage and back-pressure pollution risks. Backflow preventer valves solve this hidden danger through dual check structure and automatic pressure relief. It avoids hazardous substances such as industrial wastewater, fire-fighting additive liquid, irrigation chemical water or domestic sewage flowing back into clean tap water pipelines, which directly complies with national water supply safety and public health regulations.

Installation requirements are standardized and clear. It must be mounted horizontally with the relief drain facing downward for smooth pressure release, and a sufficient maintenance space should be reserved below the drain outlet. Regular inspection and cleaning are simple: users can disassemble the front cover to clear sediment, replace worn sealing discs and test the relief function without cutting off large pipeline sections for long periods.

Applicable media are mainly clean drinking water, domestic tap water and low-corrosion fire water. It is widely installed at key separation nodes where clean water connects to non-potable fluid pipelines.

Core Advantages

Double check plus intermediate relief structure, dual anti-backflow protection far safer than common single check valves

Automatically drains reverse pressure through the relief port to eliminate back-siphonage pollution risks

Food-grade internal sealing materials, safe for contact with drinking water supply systems

Effectively isolates contaminated downstream fluid to protect municipal clean water networks

Compact integrated design, easy on-site inspection, disassembly and routine maintenance

Multiple connection modes compatible with residential, commercial and municipal water piping standards

Main Application Scenarios

Connection points between domestic tap water and fire sprinkler systems, water supply pipelines for landscape irrigation, building water intake main pipes, factory equipment cleaning water branches, swimming pool water supply lines, commercial catering water supply nodes and municipal secondary water supply pump station outlets.