Check valves are essential plumbing components used to prevent reverse flow in pipes. They come in various designs suited to different applications. Three common types are dual plate, wafer double door, and dual disc check valves.
Dual Plate Check Valve
Dual plates check valves feature two flat plates or disc seals that move independently. When fluid flows forward, the plates separate to allow passage. In reverse flow, the plates shut tightly against each other to block flow.
They are compact in design and can be installed directly into pipelines similar to wafer check valves. Dual plate valves work well in thin piping configurations where space is limited. Applications include cooling systems, compressed air, and petrochemical processes.
Wafer Double Door Check Valve
As the name suggests, wafer double door check valves have a “wafer” style body that can be sandwiched between pipeline flanges. Inside are two hinged door panels that pivot open in forward flow and close to seal against each other in reverse flow.
The double door arrangement on these valves provide positive shut-off compared to single door designs. They are ideal for more viscous or dense fluids like slurries, mild acids, and oils. The flanged ends make them compatible with most piping systems too.
Dual Disc Check Valves
Dual disc check valves contain two circular disc seals that open and close against each other. Each disc is attached to an independent pivot stem so they move independently. This design allows smooth operation with bidirectional flexing and sealing.
Dual disc check valves excel in vibratory or pulsating fluid flow applications like hydroelectric plants or pumping stations. Their resilient disc seals suited for sealing complex fluid mixtures too. These valves are also self-relieving to prevent pressure buildup.
In summary, dual plate, wafer double door, and dual disc check valves showcase variations in design that differentiate their installation compatibility and fluid handling capabilities. Choosing the right valve type depends on the application requirements.