Sewage system: rubber duckbill check valve applied in sewage system to prevent flood and waste water from flowing backward into sewer and basement.

Drain-off system: rubber duckbill check valve applied in drain-off system to prevent flood from flowing backward when water level go up.

Dyke discharge: when rocky beach discharge, the biggest problem that flap valve face is stone and rubbish blocking, using a rubber duckbill check valve can perfectly solve this problem.

Airport and highway water draining: rubber duckbill check valve applied in airport and highway to drain water in large amount, efficiently prevent flowing backward.

Cesspool discharge: rubber duckbill check valve can prevent waste water from flowing into another working place. In untreated waste water, rubber duckbill check valve will not be influenced by plastic, branch or silk fabrics.

Smell blocking out: the rubber check valve can prevent the smell of waste water or smelt fluid, and it can drain water at any time.

Sewer drainage: in rainy season, rubber duckbill check valve can prevent waste water flowing from city inland river to street.

Aerating system: rubber duckbill check valve is the ideal choice for municipal administration and factory aerating system.

Pump station system: rubber check valve applies to large drainage pumping station, efficiently prevent backflow when water pump stop operation.