Alloy 20 Dual Plate Wafer Check Valve
High Performance • Durable • Leak Proof
Alloy 20 Dual Plate Wafer Check Valve Manufacturer in Africa for corrosion-resistant backflow prevention.
Technical Specifications
Key Features & Applications
Limited piping space can make a full-bodied check valve difficult to install, especially in chemical skids and pump discharge assemblies. An Alloy 20 dual plate wafer check valve fits between two flanges while providing spring-assisted protection against reverse flow. Its two-part disc responds faster than a heavy swing disc, and the Alloy 20 wetted construction suits many sulphuric acid and chloride-containing services. African Valve is a prominent Alloy 20 Dual Plate Wafer Check Valve Manufacturer and Supplier in Africa, serving Nigeria, Egypt, South Africa, Kenya and Ghana and exporting to the Middle East, Europe and other project locations. The disc is divided into two semicircular sections mounted on a common hinge. Forward flow opens both plates, compressing the torsion springs. When flow velocity begins to fall, stored spring force starts moving the plates toward the seat. The plates do not need to travel through a wide arc. Their lower weight and shorter stroke allow the valve to react before a large volume of fluid reverses direction. This is why dual plate check valves are frequently considered for pump systems where pressure surge is a concern. The valve must still be selected from actual flow data. Excessive line velocity can damage hinge components, while very low velocity may prevent the plates from reaching a stable open position. A wafer valve is centred between two mating flanges and held by through-bolts. No separate flange necks are built into the body. As a result, the valve is lighter and has a much shorter installation length than a flanged swing check valve. The surrounding pipeline must be correctly supported. A wafer body should not be used to pull misaligned flanges together or to carry external pipe loads. Gaskets and flange bores must also leave enough clearance for the plates to open without interference. ASTM A351 CN7M is normally used for cast Alloy 20 bodies and plates, while forged components can be supplied in ASTM A182 F20. The alloy was developed for corrosive chemical service and contains copper in addition to nickel, chromium and molybdenum. Spring and hinge materials require close attention because they are smaller stressed components. Depending on the fluid, they may be produced from Alloy 20 or another compatible nickel-based alloy. PTFE and reinforced PTFE seats are suitable for many clean chemical fluids. A metal-seated arrangement may be selected for higher temperature, abrasive particles or services where polymer degradation cannot be accepted. Size Range: DN40 to DN1200 The short body suits restricted equipment layouts. Lower disc mass improves closing response. Spring assistance limits delayed closure at falling flow. Alloy 20 withstands many acidic and chloride-bearing media. The open plates create a comparatively direct flow passage. Installation weight is lower than that of a conventional flanged valve. This design is used in sulphuric acid plants, fertilizer production, acid-transfer skids, solvent systems, pickling lines and chemical utility piping. It is also considered for corrosive pump discharge lines where reducing reverse-flow duration is more important than achieving the very lowest possible pressure drop. Inspection covers face parallelism, hinge-pin fit, plate clearance and spring movement. The body is hydrostatically tested before seat leakage is checked in the closed position. PMI can confirm Alloy 20 chemistry on pressure-retaining and wetted parts. MTCs, test certificates, inspection records and dimensional reports can be provided according to the approved project documentation schedule.Alloy 20 Dual Plate Wafer Check Valve Manufacturer and Supplier in Africa
How Do the Two Plates Close?
Wafer Installation Considerations
Selecting Alloy 20 Components
Technical Specifications
Pressure Ratings: Class 150 to Class 600; PN10 to PN100
Design Standards: API 594 and ASME B16.34
Testing Standard: API 598
End Connections: Wafer type between ASME B16.5 or EN flanges
Operation: Automatic, spring-assisted non-return actionPractical Advantages
Appropriate Process Duties
Testing and Documentation