By controlling and preventing backflow, check valves prevent discharges from wastewater treatment plants from contaminating clean water supplies. When correctly specified and functioning correctly, check valves can also help prevent flooding and standing water, ensure water flows in the correct direction and prevent potentially harmful phenomena such as water hammer. In addition, check valves are widely used to control odors. They protect residential and commercial spaces against the backflow of methane and hydrogen sulphide gases from, for example, sewers and wet wells. By providing reliable backflow prevention, check valves have saved millions in potential damage to homes, offices and vegetation.
However, some types of check valves are vulnerable to failure and wear due to their design or can become clogged with debris. For example, some check valves are vulnerable to corrosion. Similar problems can affect ball and spring check valves, where corrosion causes the valve port to malfunction. Some types of check valves can also get stuck with debris. In addition, corrosive liquids or abrasive materials such as suspended solids can cause valve or swing check valves to fail, seize, or malfunction. As a result, backflow and other associated problems such as water hammer occur. Water can also accumulate at the bottom of some types of check valves, leading to the presence of standing water. It is also true that maintenance of certain types of check valves can be expensive and difficult.
While some check valve designs are prone to corrosion, fouling and erosion, the duckbill type is made of robust rubber or other elastomeric material. As the name suggests, the duckbill valve is a flexible one-piece sleeve in the shape of a duckbill that disintegrates at the cracking pressure and closes again below this threshold. Any reverse differential pressure closes the valve tightly, preventing backflow. Duckbill check valves are ideal for stormwater applications as they are non-mechanical, require no maintenance and do not slam when closed. They are also resistant to organic contaminants such as algae and barnacles and have no problem disposing of suspended solids entrained streams, such as abrasive slurries. Suitably specified and manufactured from a suitable elastomer, check valves are also resistant to corrosive materials and are fire safe. For example, duckbill check valves contain nothing to rust or corrode and can be made from the ANSI/NSF-61 material suitable for drinking water. Such check valves will not warp and operate over a wide temperature range. Due to their extremely simple design and robust construction, rubber check valves also require no maintenance and exhibit significant service life in the range of 35 to 50 years. This is much longer than the typical 5-10 year mechanical check valves. In addition, the duckbill check valve has a low slope design that keeps the drain close to the floor and is designed to burst open just a few inches from the head. This allows complete drainage through the valve and eliminates any standing water issues.
Rubber duckbill check valves can be installed on pre-existing pipelines or other infrastructure and are often used to replace existing valves that have proved inadequate. View the product page.