Wafer Dual Disc Check Valve

Wafer (Lug) Dual Disc Check Valve is a compact, lightweight check valve designed to prevent backflow in pipelines. The “wafer” design means it is sandwiched between two flanges without having its own flanged ends, saving space and weight. It uses two spring-loaded discs that pivot on a hinge pin to allow forward flow and close on reverse flow.
It is essentially a wafer version of a dual plate (tilting disc) check valve.

1.Structure of Wafer dual Disc Check Valve

The main components of a wafer dual plate check valve:
Body – Usually made of carbon steel, stainless steel, or alloy steel; wafer type means it has no extended flanges.
Hinge Pin – Central pin on which the two semicircular discs rotate.
Discs (Plates) – Two pivoting plates that swing open with forward flow and close when flow reverses.
Springs – Assist the discs in closing quickly.
Seat – Sealing surface in the valve body to prevent backflow.
Hinge Arms – Connect the discs to the hinge pin.
Flow Direction Arrow – Marked on the body to ensure correct installation between flanges.
Wafer style allows installation between standard flanges (ANSI, DIN, JIS) with a short face-to-face length.

2. Standards of Wafer dual Plate Check Valve

Wafer dual plate check valves typically conform to:
API 594 – Check valve design standard.
API 6D – Pipeline valves.
ASME B16.34 – Valve pressure/temperature ratings.
ASME B16.10 – Face-to-face dimensions.
ISO 9001 – Quality certification.
BS 1868 / EN 12334 – European standards for check valves.
Size range: 2" – 48"
Pressure rating: Class 150 – 2500 (ANSI/ASME B16.34)

3. Features of Wafer dual Plate Check Valve

Compact and lightweight – Fits between flanges without extended body.
Low pressure drop – Minimal obstruction to flow.
Quick closure – Spring-assisted discs reduce water hammer.
Bidirectional spring assist – Works well at low flow.
Easy installation – Simply placed between flanges with bolts.
Durable – Suitable for corrosive fluids with stainless steel options.

4. Applications of Wafer dual Disc Check Valve

Water and wastewater pipelines
Oil and gas pipelines
Steam and condensate lines
Power plants
Chemical and petrochemical plants
Ideal for pipelines with space constraints where a full swing check valve is too long or heavy.

5. Operations of Wafer Dual Disc Check Valve

Forward flow: Fluid pressure pushes the discs open against spring tension, allowing flow.
Reverse flow: Discs swing back, sealing against the seat to prevent backflow.
Spring assist: Ensures quick closure at low flow rates and reduces water hammer.
Important: Automatic operation; cannot be used for throttling.

6. Maintenance Manual of Wafer dual Plate Check Valve

Routine Maintenance

Inspection: Check for leaks, seat wear, and disc alignment.
Cleaning: Remove debris that may hinder disc movement.
Lubrication: Usually not needed, but hinge pin may be lightly greased if exposed.

Maintenance Procedure

Shut down the system and depressurize the line.
Remove the valve from between flanges if needed.
Inspect discs, springs, and seat for wear or damage.
Replace damaged components (discs, pins, seats).
Reassemble and install between flanges with proper gaskets.
Test by gradually opening upstream flow and check for leakage.
Tips:
Avoid water hammer to extend valve life.
Inspect periodically in pipelines carrying solids or high-temperature fluids.