Products

Overview

Dual plate check valves (commonly designated as Dual Plate Wafer Non-Return Valves or Butterfly Check Valves) are compact, spring-loaded automatic non-return valves engineered to deliver rapid, non-slam reverse flow prevention in space- and weight-critical industrial piping systems. Unlike conventional swing check valves whose single heavy disc hangs from a top hinge, dual plate check valves utilize two semicircular D-shaped plates pivoted along a central vertical/horizontal hinge pin.

Independent torsion springs mounted on the central hinge pin exert continuous closing torque on each plate. When forward flow begins to decelerate, the spring force snaps both plates closed against the central seal rib before line flow can reverse. This spring-assisted dynamic response virtually eliminates water hammer, reverse flow surging, and acoustic slamming.

Gute Valve manufactures dual plate check valves in strict accordance with API 594, ASME B16.34, API 6D, and DIN EN 12334. Available in Wafer, Lug, Solid Lug, and Double Flanged body styles across sizes from NPS 2″ to 48″ (DN50 to DN1200) and pressure ratings from Class 150 to Class 2500 (PN16 to PN420), our valves feature an advanced Retainerless Body Architecture that eliminates through-wall pin retention holes, guaranteeing 100% fugitive emission containment on offshore platforms, chemical process plants, and marine cooling water loops.

Technical Summary

Engineering Advantages

• Extreme Space & Weight Savings (Up to 80% Lighter): The compact wafer body face-to-face dimensions per API 594 are only a fraction of equivalent flanged swing check valves. Weight savings of 60% to 80% drastically lower piping structural load, simplify crane handling, and make dual plate valves the undisputed standard on offshore FPSO topsides and marine skids.
• Retainerless Body Design (100% Fugitive Emission Prevention): Conventional dual plate check valves secure hinge and stop pins through drilled holes in the valve body sealed with threaded plugs. Gute Valve utilizes a retainerless architecture with internal blind bushings and locking plates, eliminating all external body penetrations and fugitive emission pathways.
• Dynamic Non-Slam Spring-Assisted Closure: Dual independent Inconel X-750 torsion springs drive each plate to seat instantaneously as forward velocity approaches zero, cutting reverse velocity to near zero and eliminating the water hammer shock that destroys pumps.
• Low Cracking Pressure & Smooth Plate Action: Precision plate balancing and frictionless PTFE-lined stainless bushings allow plates to crack open under minimal forward pressure differential (< 0.05 bar), maximizing flow efficiency.
• Zero Plate Rubbing (Extended Sealing Life): The plate heel lifts off the seat first during opening, preventing frictional dragging of the seating face across the seat ring and ensuring long-lasting seal integrity.

Typical Applications

• Offshore Oil & Gas Platforms, Drilling Rigs & FPSO Topsides Modules
• High-Capacity Cooling Water Circulation Loops & Desalination Skids
• Petrochemical Refineries & Hydrocarbon Transfer Manifolds
• Water & Wastewater Treatment, Potable Water Pumping Stations
• District Cooling & HVAC Chilled Water Circulation Mains
• Shipbuilding, Marine Ballast Systems & Engine Room Utilities
• Chemical Processing Acid & Caustic Transfer Skids

Dual Plate Check Valve Engineering Selection Guide

Engineers specifying API 594 dual plate check valves should evaluate body pattern styles, spring metallurgy, and sealing interfaces:

• Body Style Selection (Wafer vs. Lug vs. Double Flanged):
  • Wafer Pattern: Lightest weight and lowest cost; clamped between pipeline flanges with long stud bolts. Recommended for general process lines where down-pipe dismantling is not required.
  • Lug & Solid Lug Pattern: Features threaded bolt holes matching pipe flanges, allowing downstream pipe dead-end service and removal of downstream spools without draining upstream headers.
  • Double Flanged Pattern: Required by offshore and pipeline specifications where long through-bolts are prohibited due to fire-exposure thermal expansion or structural bending stresses.
• Retainerless vs. Retained Pin Architecture: Always specify Retainerless Construction for flammable hydrocarbons, lethal chemicals, sour gas (H2S), and high-pressure duties to comply with modern fugitive emission environmental mandates.
• Seat Selection (Resilient vs. Metal-to-Metal):
  • Resilient Seats (EPDM, Viton, NBR, PTFE): Recommended for ambient water, air, and clean chemicals up to 150°C requiring EN 12266-1 Rate A bubble-tight shut-off.
  • Metal Seats (Integral or Stellite 6 Overlay): Mandatory for high temperatures (> 150°C up to 400°C), abrasive fluids, steam, and hydrocarbon services requiring API 607 fire-safe performance.
• Piping Orientation: Suitable for both horizontal and vertical pipelines with upward flow. For vertical flow upward, specify heavy-duty springs to assist downward plate return.

Material & Trim Options

• Body Materials: ASTM A216 WCB, ASTM A352 LCB/LCC, ASTM A351 CF8 (304), CF8M (316), CF3M (316L), ASTM A995 4A (Duplex 2205) / 5A (Super Duplex 2507), Aluminium Bronze (ASTM B148 C95800 for seawater).
• Plates: ASTM A351 CF8M, CF3M, Duplex 2205, Super Duplex 2507, Monel, Inconel 625, Hastelloy C276.
• Torsion Springs: Inconel X-750 (Standard for high-fatigue cycle life and thermal stability up to 400°C), Inconel 718, or 316 Stainless Steel.
• Hinge & Stop Pins: Hardened ASTM A276 316, 17-4PH, or Inconel 718.

Frequently Asked Questions

1. Why are dual plate wafer check valves preferred over conventional swing check valves on offshore platforms?

Weight and space constraints dominate offshore FPSO and platform design. An NPS 12″ Class 300 dual plate wafer check valve weighs approximately 45 kg and has a face-to-face length of 73 mm, whereas an equivalent flanged swing check valve weighs over 280 kg and spans 698 mm. Dual plate valves reduce structural deck load by up to 80% while fitting into tight piping racks.

2. What is a “Retainerless” dual plate check valve, and why is it important for safety?

In standard dual plate valves, the hinge and stop pins penetrate the outer valve body and are sealed with threaded external plugs. High pipeline pressures, vibration, and thermal cycling can loosen these plugs, creating catastrophic external leaks. A retainerless design inserts the pins from the bore opening, locking them internally with blind clips and plates—eliminating all body penetrations and achieving zero external leakage.

3. How do the independent torsion springs protect pumps from water hammer?

In a dual plate valve, each plate has an independent spring that exerts continuous closing force. When forward fluid flow begins to slow down, the spring drives the lightweight plates closed before the flow completely reverses. Closing at zero reverse velocity prevents the dynamic pressure surge (water hammer) that damages pumps and pipes.

4. Can dual plate check valves be installed in vertical piping lines?

Yes, provided the flow direction is vertically upward. The dual torsion springs close the plates reliably regardless of gravity. However, dual plate check valves must never be installed in vertical lines with downward flow, as gravity would prevent proper plate closure.

5. What is the allowable leakage rate for dual plate check valves under API 598 testing?

Dual plate check valves fitted with resilient elastomeric seats (Viton, EPDM, NBR) achieve zero bubbles (Rate A per ISO 5208 / EN 12266-1) during API 598 low-pressure gas testing. Metal-seated valves (Stellite 6 or 316SS) are tested under high-pressure liquid closure per API 598, with allowable leakage strictly compliant with standard metal seat tolerances.