A Dual Plate Check Valve (also called a double door or wafer check valve) is designed to
prevent backflow in piping systems. It uses two spring-loaded plates that open with forward
flow and close quickly to prevent reverse flow, minimizing water hammer. This manual
outlines best practices for the valve’s lifecycle, including handling, installation, and
maintenance.
2.1 Transportation
Keep the valve in its original packaging during handling and shipping.
Use proper lifting techniques or equipment, especially for large-diameter valves.
Protect the valve from mechanical impacts and rough handling.
Avoid exposure to rain, moisture, and corrosive environments during transport
2.2 Storage
Store in a clean, dry, and shaded area.
Maintain ambient temperature and humidity to avoid condensation.
Plug or cap valve ends to prevent ingress of debris or insects.
Avoid stacking heavy items on the valve to prevent deformation
3.1 Pre-Installation Checklist
Verify the valve is suitable for the intended service (media, pressure, temperature).
Inspect the valve for shipping damage or contamination.
Clean valve and pipeline interior to remove dust, scale, or foreign material
3.2 Installation Guidelines
Ensure the flow arrow on the valve body matches the system flow direction.
Install the valve between flanges using the appropriate gaskets.
Center the valve properly to avoid interference with plate movement.
Avoid over-torquing flange bolts—tighten bolts in a crisscross pattern to ensure even compression.
Vertical installation is preferred with upward flow; horizontal installations should ensure that plates swing open easily
3.3 Piping Support
Properly support upstream and downstream piping to reduce stress on the valve.
Do not use the valve to support pipe weight
The valve operates automatically based on flow direction and pressure.
It requires no manual operation or external power.
Sudden flow reversal or high-pressure differentials may cause premature wear or
noise (water hammer).
6.1 Inspection Frequency
Inspect every 6–12 months depending on application severity.
In aggressive or dirty services, inspect more frequently
6.2 Routine Maintenance
Remove valve from the line for thorough inspection.
Check for corrosion, cracks, spring integrity, and seat wear.
Clean all components using appropriate cleaning agents.
Replace worn or damaged parts with OEM-approved components.
6.3 Reassembly and Testing
Ensure all moving parts function freely before reassembly.
Use new gaskets and apply uniform bolt torque during reinstallation.
Pressure test valve to system specs before resuming operation.
Fully depressurize and isolate the pipeline before removal or servicing.
Wear personal protective equipment (PPE) appropriate for the service media.
Use proper lifting tools and methods to handle heavy valves.
Follow lockout-tagout (LOTO) procedures in industrial environments
Dispose of according to local regulations for metals and elastomers.
Recycle metal components where facilities exist.
Remove hazardous media residues before disposal