Wafer Check Valve -> Dual-plate Wafer Check Valve
Dual-plate check valves are are bonnetless and mounted between pipe flanges (wafer style). In this case, the valve includes two spring loaded half-moon shaped discs that rotate about their shaft. The actual designs of these valves vary between design models and manufacturers. Most have multiple flat seats. The dual-plate Check Valve disc has short rotational disc travel and responds quickly to flow stoppage or reversal, thus the potential for moderate water hammer does exist. It is somewhat better than the Swing Check Valve at minimizing potential water hammer, but with a much higher pressure drop.
Depending on the design, maintenance effort ranges from relatively simple to difficult. All dual-plate check valves must be removed from the line to perform maintenance due to the bonnetless design. The dual-plate Check Valve also results in a higher pressure drop when compared to a Tilting Disc Check Valve of the same size.
Sizes: 2" - 48" or DN50 - DN1200
Pressure Rating: Class150 - Class1500 or PN16 - PN250
Material of Valve Body: WCB, LCB, WC6, WC9, C5, CF8, CF3, CF3M, CF8M, etc.
Features of Dual-plate Wafer Check Valve:
One Piece Body Design
Inline Double Plate
Spring-loaded Disc for Quick Closure
Wafer End Standard, Flanged Ends Available
Applicable Standards of Dual-plate Wafer Check Valve:
Design & Manufacture: API 6D, API 594
Face to Face: API 6D, ASME B16.10, EN 558
Connection End: ASME B16.5, EN 1092, JIS B2220
Test and Inspection: API 6D, EN 12266, API 598