allow free flow with positive differential pressure.  With negative differential pressure, backflow is checked.  Pressure drop across the valve is a feature unique to .  They can be designed to operate in a few millimeters (inches) of water to several hundred kPa (psi), depending on valve size, geometry and compound characteristics.  are also designed to start functioning at specific opening and closing pressure ranges, depending on your specifications. Flange Connected Duckbill Check Valve(2"-96") Supply range is from 50mm to 2400mm

the Material can be Stainless Steel/Cast Iron/Forged Steel Rubber can be NR/NBR/EPDM/NEOPRENE for your option Cost-effective and Maintenance Free Backflow Prevention Automatically Most Professional Manufacturer From China.

 Features:

Easy installation with ring flange, drilling can be DIN/JIS/EN/ANSI, etc.

Reliable backflow prevention

       Lower head loss than conventional check valves

       100% elastomeric construction eliminates maintenance

Will not corrode, warp or freeze open or shut

1" -2" Cracking Pressure, Low Head loss

Custom built for each application based on pressure and flow conditions

Reliable and cost-effective alternative to flap-gate and other conventional check valves

       Maintenance-free operation with no mechanical components that can corrode or seize

       Will open with as little as 1" W.C.

       Quiet operation (non-slamming)

       Excellent corrosion and abrasion resistance

       Versatile construction for a wide range of applications

       Manufactured with an integral reinforced rubber flange provided with metal retaining rings for easy bolting directly to the pipe flange, tank wall or head wall

       Flanges drilled per standard ANSI B16.1/150 lb. pattern; other drilling patterns are available upon request Retaining ring available in galvanized, 304 stainless steel and 316 stainless steel

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