Non-Return Valves
Overview
Non-Return Valves (Check Valves) are designed to allow fluid to flow in only one direction, automatically closing to prevent backflow whenever flow reverses. These valves are crucial in protecting pumps, compressors, and other system components from reverse flow damage. Available in a variety of materials and pressure ratings, non-return valves find widespread use in water distribution, oil & gas pipelines, chemical processing, and other industrial fluid handling applications.
Key Uses & Applications
Pump Protection
Prevents backflow damage to pumps during shutdown or power failure. Maintains prime in the suction line by not allowing fluid to drain back.
Oil & Gas
Ensures one-direction flow in wellheads, pipelines, and processing facilities. Commonly installed downstream of pumps or compressors for safety.
Water & Wastewater
Stops reverse flow in municipal water systems, sewage treatment, and stormwater pumping stations. Minimizes water hammer occurrences by promptly closing upon flow reversal.
Chemical & Petrochemical
Protects process equipment from corrosive or hazardous fluid backflow. Maintains system integrity in high-temperature, moderate-to-high pressure lines.
Power Generation & Steam
Used in steam lines, feedwater systems, and condensate return loops. Check valves in boiler rooms help prevent reverse steam flow or condensate back-up.
Product Highlights
Size Range
2" to 24" - Covers small to large flow pipelines in industrial, municipal, and commercial settings.
Pressure Ratings
PN16, Class 150 (#150), Class 300 (#300), Class 600 (#600). Accommodates low to high-pressure services depending on project requirements.
Valve Types
Swing Check Valve: Hinged disc swings open with forward flow and closes when flow reverses. Common in water and general fluid applications. Lift Check Valve: Vertically oriented disc or piston lifts with forward flow and seats by gravity or spring force on flow reversal. Often used in smaller or higher-pressure lines. Dual Plate / Wafer Check Valve: Compact design with two spring-loaded plates, suitable for space-constrained environments.
Body & Disc Materials
Body: Cast iron, ductile iron, carbon steel (WCB), stainless steel (CF8/CF8M), or alloy steels for specialized applications. Disc/Plate: Stainless steels or other alloys to resist corrosion and ensure durability. Sealing: EPDM, NBR, or metal-to-metal seats, depending on fluid and temperature range.
Flow Efficiency
Designed to minimize pressure drop while open. Rapid closure on reverse flow reduces surge and water hammer.
Technical Specifications
| Valve Type | Non-Return / Check Valve (Swing, Lift, Dual Plate, etc.) |
| Size Range | 2" – 24" (DN50 – DN600) |
| Pressure Ratings | PN16, Class 150 (#150), Class 300 (#300), Class 600 (#600) |
| Design Standards | API 6D, API 594, BS EN 12334 / 1868, ASME B16.34, EN 1092-1 (flanges) |
| Body Materials | Cast Iron, Ductile Iron, Carbon Steel (WCB), Stainless Steel (CF8/CF8M), Alloy Steel |
| Disc/Seat | 13Cr, SS304, SS316, Duplex, Bronze, or specialized coatings |
| End Connections | Flanged (RF / RTJ), Wafer / Lug (for wafer check valves), BW (Butt Weld) |
| Operating Temperature | -29°C to ~425°C (Carbon Steel); up to +540°C (Alloy Steel) depending on seat & material |
| Leakage Class | Typically meets API 598 or EN 12266 leak test requirements |
| Closure Mechanism | Gravity, spring-assisted, or hinged disc |
Design & Performance Features
Swing Check Valve
A hinged disc pivots out of the flow path when open, returning to seat by gravity or backpressure. Ideal for larger pipelines or low-to-moderate flow velocities.
Lift Check Valve
Uses a disc or piston that lifts off the seat with flow pressure; gravity or spring forces close it when flow reverses. Common in horizontal lines (sometimes vertical) where tighter sealing is needed.
Dual Plate / Wafer Check Valve
Slim, lightweight design with two spring-loaded plates that fold against each other on forward flow. Rapid closing reduces water hammer risk in high-velocity or pulsating flows.
Metal-to-Metal or Soft Seating
Metal-to-Metal seats handle higher temperatures and pressures. Soft seats (EPDM, NBR, Viton) provide bubble-tight closure in lower temperature ranges.
Minimal Flow Restriction
Low pressure drop across the valve in the open position. Some designs include an optimized disc profile or guide to improve flow efficiency.