A duckbill check valve is a type of check valve that is often used to prevent backflow. It is a one-way, non-mechanical check valve that closes after a certain pressure has been applied. It is generally made of a flexible material, such as rubber, nylon, polypropylene or Kynar(r). However, the material of the valve can vary depending on the application.
Duckbill check valves are typically used in applications involving sewage, raw water, metering, dredging, or sewage interceptors. In sewage applications, they are usually installed in pipe systems that have a high pressure differential. They can also be used to remove suspended solids. A duckbill valve is usually designed with an undercut, which provides a larger sealing area. They can be fitted to various types of pipe, including metal, corrugated, steel, or PVC pipes.
Duckbill check valves are able to withstand organic contaminants, high temperatures, and pressure. They can be operated by hand without the need for power or assistance. They are also rust-resistant. A duckbill valve can work in deep waters, up to three meters. When used in the marine environment, it is recommended that the valve be made from Neoprene rubber, which will help stop barnacle growth.
There are many different duckbill check valves on the market. Some of them are made of a flexible material, while others are made of a metal, which can corrode. Some are a slip-on model, which is a good option for fitting on the headwall of a pipe. Some are flanged, which are available in different styles. Some are clamp-type, which are commonly found in municipal flooding, reservoirs, and sewage.
Some of the main features of duckbill check valves include their resistance to abrasive materials, such as mud or sand. These are particularly useful for wastewater treatment plants and sewer interceptors, because they can handle rough and abrasive conditions. Besides, their flaps protect against contamination from backflow.
There are two types of duckbill check valves: the duckbill check valves curved bill and the straight bill. The curved bill is a better choice for the prevention of backflow, because it provides about 50% more sealing surface. On the other hand, the straight bill model opens with minimal cracking pressure. The cracking pressure will depend on the materials and the hardness of the material.
In addition to the cracking pressure, the type of material the duckbill check valve is made from will affect its performance. It is important to choose a rubber duckbill check valve that can handle abrasive materials. It can also be a good idea to purchase a valve that is made from a fire-retardant elastomer.
When choosing a duckbill check valve, make sure that the flange is in the proper position. If it is not, the valve may rotate before fasteners are inserted. This could cause the valve to break or become damaged. It is also important that the flange is tightened properly. This is because the flange acts as a gasket between the mating flanges.