HomeValve ComparisonsSwing Check Valve vs Dual-Plate Check Valve

Valve Comparison Guide

Swing Check Valve vs Dual-Plate Check Valve — Which Non-Return Valve?

Swing check valve vs dual-plate (wafer) check valve: pressure drop, slam risk, installation and standards compared. Choose the right non-return valve for pipelines, pumps and compressors.

Overview

Swing Check Valve

A swing check valve uses a hinged disc that swings open with forward flow and closes by gravity and reverse flow pressure. It is the simplest and most economical check valve design, suitable for moderate flow velocities in liquid and gas service.

DN50–DN900, Class 150–600, A216 WCB / A351 CF8M, API 6D / ASME B16.34

Dual-Plate Check Valve

A dual-plate (or double-disc, wafer) check valve uses two spring-loaded half-discs that open in the centre. Spring assist ensures rapid, controlled closure before flow reversal, minimising slam and water hammer. Compact wafer design fits between flanges.

DN50–DN600, Class 150–1500, A216 WCB / A351 CF8M / A182 F51, API 6D

Pros & Cons

Swing Check Valve

Low forward pressure drop in fully open position
Simple, robust design — low maintenance
Full bore — disc swings fully out of flow path
Low cost for large bore applications
Suitable for both horizontal and vertical (up-flow) installation
Slam risk — disc can slam shut on flow reversal (water hammer)
Not suitable for pulsating or rapidly reversing flow
Large physical size — long face-to-face dimension
Slow closure — not ideal for pump discharge without surge dampening
Not suitable for vertical downward flow installation

Dual-Plate Check Valve

Very compact — wafer body, short face-to-face
Lightweight — 5–10× lighter than swing check at same bore
Spring-assisted closure — minimal slam and water hammer
Suitable for high-velocity, pulsating, and vertical service
API 6D certified for pipeline service
Works in any orientation — horizontal, vertical, or inclined
Higher pressure drop than swing check (discs and spring in flow path)
Not full bore — spring and hinge bar create turbulence
Slurries and viscous fluids can foul the spring mechanism
More complex — higher maintenance at very large bore

Swing Check Valve vs Dual-Plate Check Valve — Specification Comparison

ParameterSwing Check ValveDual-Plate Check Valve
DesignSingle hinged discTwo spring-loaded half-discs
BoreFull bore — disc clears flow pathReduced bore — discs and spring in flow
Pressure DropLower (full bore, fully open)Slightly higher (spring and hinge bar)
Slam / Water HammerHigh risk — disc free to slamMinimal — spring ensures gentle controlled closure
WeightHeavy — long body, swing mechanismVery light — wafer body, no extended swing arm
Face-to-FaceLong (ASME B16.10)Very short (wafer — between flanges)
InstallationHorizontal or vertical (up-flow only)Any orientation
Slurry / Dirty FluidsBetter — simple hinge, no spring to foulSpring may foul with slurries
CostLower at large bore (DN300+)Lower at small-medium bore (DN50–DN200)
StandardsAPI 6D, BS 1868, ASME B16.34API 6D, API 594, ASME B16.34

When to Use Each

Use Swing Check Valve when:

Gravity-flow or low-pulsation liquid systems
Water distribution and irrigation mains
General purpose pump discharge (low water hammer risk)
Large bore applications where cost is critical
Horizontal pipelines with low flow reversal velocity

Use Dual-Plate Check Valve when:

Oil & gas pipeline service (API 6D) — compact and lightweight
Pump and compressor discharge — spring prevents slam
Vertical upward or downward pipeline installation
High-velocity service where water hammer is a concern
Offshore platforms — weight and space are premium

Decision Guide

Use a dual-plate check valve for oil & gas pipelines (API 6D), pump and compressor discharge where water hammer is a concern, offshore or weight-critical installations, and vertical pipeline configurations. Use a swing check valve for large bore (DN400+) gravity-flow or low-pulsation liquid systems where cost is the priority and water hammer is not a concern.

Frequently Asked Questions

Which check valve is better for pump discharge?
Dual-plate check valves are preferred for pump discharge because spring-assisted closure prevents the sudden flow reversal that causes slam (water hammer) when a pump trips. This is especially critical for high-head pumps and multiple pump installations. Swing check valves on pump discharge can cause significant pressure surge unless a slow-closing (weighted disc or dashpot-assisted) design is used.
Can a dual-plate check valve be installed vertically?
Yes — dual-plate check valves with springs can be installed in any orientation: horizontal, vertical upward, or vertical downward flow. Swing check valves can only be installed in horizontal or vertical upward flow configurations. Vertical downward installation of a swing check valve prevents gravity-assisted closing and will not work.
What does API 6D mean for check valves?
API 6D is the American Petroleum Institute standard for pipeline valves including check valves. API 6D check valves must comply with specific pressure-temperature ratings, leakage testing (API 598), materials, and dimensions. For mainline oil & gas pipeline service, API 6D certification is typically required. Both swing and dual-plate designs are available in API 6D versions.

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