Super Duplex Dual Plate Check Valve

Compact seawater and brine systems often need reverse-flow protection where space and installed weight are limited. A wafer dual plate valve fits between pipeline flanges and uses spring-assisted plates for a short closing movement. African Valve is a prominent Super Duplex Dual Plate Check Valve Manufacturer in Africa, supplying South Africa, Nigeria, Egypt, Angola, other African countries and international projects.

Super Duplex Pressure Parts

The body and plates may use ASTM A995 Grade 5A, while the pin, springs and retainers use F53, F55 or another compatible Super Duplex grade. Material selection should cover every wetted part. A lower-alloy spring or pin can corrode before the body shows visible damage.
Super Duplex provides high strength and a strong resistance margin against chloride pitting, crevice corrosion and stress-corrosion cracking. Correct heat treatment, ferrite balance and fabrication control remain necessary.

Seat and Spring Selection

Metal seats are used where temperature, solids or repeated cycling make a soft seat unsuitable. PTFE or resilient seating may provide tighter shutoff in clean seawater and chemical service.
Spring torque affects cracking pressure, pressure drop and closure. For vertical upward flow, the spring arrangement should be selected for the valve position. A valve installed horizontally may require a different spring package from one installed vertically.

Technical Specifications

Size Range: DN50 to DN1200
Pressure Ratings: ASME Class 150 to Class 600
Design Standards: API 594 and ASME B16.34 where applicable
Testing Standard: API 598
End Connections: Wafer, installed between mating flanges
Operation: Automatic, flow actuated
Body Material: ASTM A995 Grade 5A or compatible Super Duplex grade
Plate Design: Dual spring-assisted plates
Seat Options: Metal, PTFE or resilient seat
Installation: Horizontal or vertical upward flow when approved

Flow Performance and Installation

The valve should be selected from operating flow data. If it is oversized, the plates may remain partly open and flutter, increasing spring fatigue, hinge wear and seat impact. Manufacturer pressure-loss data should be reviewed at normal and minimum flow.
Accurate centring between flanges is essential. Misalignment can restrict plate movement or load the body unevenly. The adjoining pipe bore must also provide enough clearance for the plate edges and hinge assembly. Flange faces should remain parallel so the wafer body is not distorted during bolt tightening.

Compact Check Valve Supply

African Valve supplies Super Duplex dual plate wafer check valves for marine and process projects across Africa. The RFQ should include fluid chemistry, flow rate, minimum velocity, pressure, temperature, orientation, flange standard, cracking pressure and seat requirement.