Duckbill check valves are one-way check valves that prevent backflow in a piping system. These valves require no mechanical intervention to open or close – they operate by a pressure differential across them, allowing fluids to flow in one direction and then preventing them from flowing in the opposite direction.
The duckbill type is a very simple and robust design that is highly resistant to corrosion, fouling and wear. It also provides a smooth, leak-free operation that does not slam shut when closed. It is therefore an ideal valve for use in sewage treatment plants, stormwater outfalls, effluent discharge and flood control applications.
It is made from a fire-retardant elastomeric material that offers excellent resistance to biological contamination such as barnacles and algae. It can handle abrasive slurries and is non-silting, reducing maintenance costs.
When the difference between the forward and reverse water levels exceeds a certain threshold, the duckbill check valves valve automatically opens to stop backflow. Usually, the difference between the forward and reverse water levels only needs to exceed 10mm to open the valve. This prevents the occurrence of pressure loss and ensures that the valve is able to function in all environments, including extremes of temperature.
Moreover, this type of valve does not need any power source or manual operating assistance to operate, so it is an extremely cost-effective method of controlling back pressure. It is widely used in sewage treatment plants and other wastewater applications, as well as for controlling odors in residential areas.
They can be manufactured from a variety of materials, including medical and food-grade silicone, liquid silicone rubber (LSR) for healthcare or baby products like breast pump check valves and hydrocarbon-resistant fluorosilicone rubber (FVMQ) to handle a broad range of media and temperatures. They can be adapted for specific piping systems or applications and have various sealing types and styles, such as self-sealing, mechanical or flanged.
The main advantages of this type of valve are the following:
No clogging, jamming or failure to operate; high reliability and durability due to its robust, abrasive-resistant construction; easy installation in various environments without the need for mechanical assembly; no slam or noise when closed; and low maintenance requirements.
This type of valve can be produced with a variety of elastomer materials, such as medical and food-grade silicone, liquid silicone (LSR) for healthcare or baby products, Buna N & Nitrile Rubber, Neoprene / CR, and fluorosilicone rubber (FVMQ). They are available in all different shapes and sizes, making them an ideal choice for all kinds of applications.