Corrosion-Resistant Swing Check Valve — Wafer Type, WCB Body with PFA Lining, Horizontal and Vertical

The corrosion-resistant wafer-type swing check valve is the most versatile retention component for extreme corrosive fluids. Unlike gravity-actuated ball check valves, which require mandatory vertical installation, the wafer swing check functions correctly in horizontal and vertical pipelines with upward flow. Its wafer design — without its own flanges, installed directly between pipeline flanges — makes it the most compact and lightweight in the family of corrosion-resistant check valves, occupying minimal axial space in the line. The body and disc are made of WCB with a continuous PFA lining — no metal surface is exposed to the fluid. The swing-type disc opens with the fluid flow in the correct direction and automatically closes when the flow stops or attempts to reverse, without a spring or external mechanism — only the disc's weight and fluid backpressure generate the closure.

Wafer Swing vs. Corrosion-Resistant Ball Check — When to Choose Each

Both valves handle extreme corrosive fluids with PFA lining but have critical operational differences:

Criterion	PFA Wafer Swing Check ← This product	PFA Ball Check (flanged)
Horizontal installation	✅ Yes — first choice	❌ No — vertical upward only
Vertical upward installation	✅ Yes	✅ Yes — mandatory
Connection format	✅ Wafer — between flanges, no body of its own	Flanged — with its own flanges
Axial space required	✅ Minimum — compact wafer design	Greater — flanged body with ASME face-to-face
Closing mechanism	Swing disc — closes by weight and backpressure	PTFE ball — drops by gravity
Closing speed	Fast — disc pivots on a hinge	✅ Immediate — ball drops instantly
Particle tolerance	Medium — particles can prevent disc closure	✅ Greater — floating ball tolerates fine solids
Crystallizing fluids	⚠️ Crystals can adhere to the disc seat	✅ Greater — self-cleaning rotating ball

Operating Principle — Springless Swing

The disc of the swing check valve is articulated on a hinge at the top of the body. It operates in two states: * Flow in correct direction — open disc: Fluid pressure pushes the disc backward, rotating it on the hinge to the open position. The disc remains open as long as the flow maintains its direction and speed — without any active component to keep it open. * Stopped flow or backpressure — closed disc: When flow stops or backpressure is generated, the disc falls by its own weight, and backpressure pushes it back against the body seat, sealing the passage. Closure is silent and without abrupt impact — closing speed is modulated by the disc's weight and hinge geometry. Springless: The absence of a spring eliminates the component most susceptible to corrosion and fatigue in conventional check valves. In aggressive fluids that would attack a metallic stainless steel spring in weeks or months, the springless swing check provides significantly longer service life.

Wafer Construction — Installation Advantages

The wafer format is the same concept as the wafer butterfly valve: the valve is installed compressed between two pipeline flanges, secured by the flange connection bolts. It has no own flanges — the valve body is the connecting element. Specific advantages in aggressive chemical installations: * Minimum axial space: The wafer's face-to-face dimension is the shortest of all check valve types — ideal for installations with limited space between equipment. * Lighter weight: Without its own flanges, the wafer weighs significantly less than the equivalent flanged check valve — an advantage in elevated installations or in structures with load limitations. * Fewer flanged connections: By installing between existing pipeline flanges, it does not add additional connections to the line — each flanged connection in an aggressive acid line is a potential leak point. * Lower installation cost: No own flanges to bolt — the wafer is installed in minutes between pipeline flanges with existing bolts.

Valve Components

No.	Component	Material	Fluid Contact
1	Body	A216 WCB + PFA lining	✅ Yes — PFA lined
2	Disc	A216 WCB + PFA lining	✅ Yes — PFA lined
3	Lining material	PFA	✅ Continuous chemical barrier
4	Bolt	A193 B7	No

PFA-lined body and disc — no metallic surface exposed to the fluid in any open or closed position.

Technical Specifications

• Type: Wafer swing check valve — installation between flanges
• Design Standard: ASME B16.34
• Face to face: ASME B16.10
• Flanges: Class 150LB
• Inspection and Testing: API 598
• Body Material: A216 WCB + PFA lining
• Disc Material: A216 WCB + PFA lining
• Internal Lining: PFA
• Bolts: A193 B7
• Nominal diameters in stock: ½", ¾", 1", 1¼", 1½", 2", 2½", 3", 4"
• Diameters on request: 5", 6", 8", 10", 12", 14"
• Working Pressure: PN16 (232 psi / 16 bar)
• Working Temperature: -20 °C to +200 °C — verify concentration and temperature of specific fluid
• Installation: Horizontal or vertical with upward flow
• Closure: By disc weight and backpressure — springless
• Vacuum Capacity: Up to 0.1 mbar according to pressure-temperature curve

Pressure-Temperature Curve

Temperature	Approx. max pressure (PFA)
-20 °C to +50 °C	~15–16 bar
100 °C	~12–13 bar
150 °C	~6–7 bar
180 °C	~6 bar
200 °C	~6 bar

Approximate values according to datasheet curve. Verify official curve for final design.

Chemical Compatibility

• ✅ Hydrochloric acid HCl — any concentration
• ✅ Nitric acid HNO₃ — including concentrated
• ✅ Hydrofluoric acid HF — any concentration
• ✅ Liquid chlorine Cl₂
• ✅ Sulfuric acid H₂SO₄ — including concentrated
• ✅ Sodium hypochlorite NaClO
• ✅ Concentrated alkalis (NaOH, KOH)
• ✅ Aggressive organic solvents
• ✅ High-purity fluids — no metallic leaching
• ⚠️ Fluids with solid particles: PFA ball check is more suitable — particles can prevent tight closure of the swing disc
• ⚠️ Always verify specific process concentration and temperature

Main Applications

• Reflux prevention in horizontal acid lines: The most frequent application and the main differentiator compared to the ball check. Any horizontal process line with HF, H₂SO₄, HCl, HNO₃ or ClO₂ requiring retention without reflux — the PFA wafer swing check is the first choice due to its compatibility with horizontal installation.
• Pump protection in corrosive lines: Installed at the discharge of pumps handling corrosive fluids, the swing check prevents aggressive acid from returning to the pump when it stops — protecting the pump's seals and internal components from return water hammer.
• Chemical and petrochemical industry: Retention in transport, dosing, and recirculation lines for mineral acids, strong alkalis, and aggressive solvents. The wafer format minimizes the number of flanged connections in the line — critical in acid installations where each joint is a potential leak point.
• Mining — acid leaching and SX-EW: Retention in H₂SO₄ leaching circuits and in copper electrodeposition electrolyte lines. The wafer format is especially valued in these installations where space between equipment is limited and the weight of components in metal structures is relevant.
• Water treatment — aggressive reagent dosing: Retention in dosing lines for liquid chlorine, concentrated hypochlorite, and pH adjustment acids. Horizontal installation is possible — an advantage in plants where dosing lines run in horizontal collectors.
• Pharmaceutical and semiconductors: Prevention of cross-contamination between aggressive process fluid lines. PFA does not release extractables into the fluid — essential in high-purity processes where metallic contamination is unacceptable.
• Protection and safety circuits: Prevention of unwanted mixing between two incompatible reagent lines — if both lines converge at one point, the corrosion-resistant check valve in each line ensures that no reagent can flow back into the incompatible reagent line.

For the complete range of corrosion-resistant valves, see PFA corrosion-resistant valve category →

 

Technical Data Sheet