Product Category
Industrial Check Valves
Non-return valves that automatically prevent reverse flow in pipelines and process systems. Swing check, lift check, dual-plate wafer, tilting disc, and axial flow designs for water, oil, gas, steam, and chemical service.
Check Valve Types
Swing Check Valves
A hinged disc swings freely on a hinge pin in the valve body. Forward flow pushes the disc open; reverse flow causes the disc to swing back and seat against the body seat ring. Low pressure drop in the open position — the disc swings fully out of the flow path. Not suitable for pulsating flow or vertical downward flow. Standard for water, sewage, oil, and general process lines where space permits. Brands: Crane, Mueller, AVK, KSB, Flowserve.
Lift Check Valves
The disc or piston lifts vertically off its seat in response to forward flow, guided by a cage or body guides. When flow stops, gravity and back pressure close the disc. More responsive than swing checks in vertical installations. Suitable for vertical pipelines (flow upward). Higher pressure drop than swing type. Used in high-pressure steam, compressor discharge, and pump discharge service. Brands: Crane, Velan, KSB, Spirax Sarco.
Dual-Plate Wafer Check Valves
Two semicircular plates (split disc) hinged at the centre of the body, held closed by a central spring. The compact wafer body clamps between flanges — much shorter face-to-face than swing checks. Very fast closing (spring-assisted) reduces water hammer on pump trip. Suitable for both horizontal and vertical installations. The most common check valve for pump discharge in water and process systems. Brands: Crane Duo-Chek, Flowserve (Valcheck), Neway, KSB.
Tilting Disc Check Valves
The disc pivots about a hinge point located above the disc centre — as flow opens the disc, it tilts to a near-horizontal position that minimises turbulence and pressure drop. The tilted open position means the disc is already partly-closed relative to swing checks, so it closes faster on flow reversal. Suitable for pulsating flow, pump discharge, and compressor outlet where slam is a concern. Brands: Crane Tilting Disc, Flowserve, Velan, KSB.
Axial Flow (Nozzle) Check Valves
A streamlined poppet spring-loaded coaxially in the valve body. The poppet opens against spring force when forward flow exceeds the cracking pressure; the spring closes the poppet immediately on flow reversal — before reverse flow develops, eliminating water hammer. The lowest pressure drop of all check valve types (streamlined nozzle body). Used for compressor inter-stage, gas pipelines, large pump discharge mains, and any service where silent, slam-free operation is essential. Brands: Nozzle Check (Crane), Flo-Tite, AVK, Wafer Check specialists.
Ball Check Valves
A ball seats in a conical seat and is lifted by forward flow. Used primarily for pumping viscous fluids, slurries, and liquids with solids — the ball self-centres and resists clogging. Common in metering pumps, chemical dosing, and small-bore instrument lines.
Selection Considerations
- Flow velocity: Swing checks require minimum velocity to hold open — at low velocities, the disc flutters and wears. Dual-plate and axial types tolerate lower velocities.
- Water hammer: Large swing checks on pump discharge can slam violently on pump trip — use dual-plate wafer or tilting disc with spring assist where slam is a concern.
- Installation orientation: Most check valve types require specific orientation — check manufacturer requirements for vertical installations.
- Pressure drop: Axial nozzle check valves have the lowest Cv; lift checks and ball checks have the highest pressure drop.
Design Standards
- API 594: Wafer, wafer-lug, and double-flanged check valves — the primary standard for dual-plate wafer checks.
- API 6D: Pipeline valves — check valves for gathering, transmission, and distribution pipelines.
- API 602: Forged steel small-bore check valves (≤ DN 100).
- BS 1868 / EN 12334: Steel check valves for general use.
- ASME B16.34: Pressure-temperature ratings.
| Brand | Types | Key Products / Notes |
|---|---|---|
| Crane Valves | Swing, tilting disc, dual-plate, lift | Crane Duo-Chek II (dual-plate), tilting disc — API 594 & 6D |
| Flowserve | Swing, dual-plate, axial | Valcheck, Durco — process and pipeline check valves |
| Velan | Swing, lift, tilting disc | API 602 forged, cryogenic check valves, nuclear applications |
| KSB | Swing, dual-plate, lift | RVK, ECOLINE — PN 16 to PN 250, DN 15 to DN 500 |
| AVK Group | Swing, dual-plate | Water and wastewater check valves — large-diameter infrastructure |
| Mueller Water Products | Swing, foot | Resilient-seated swing check for water distribution |
| Neway Valve | Swing, dual-plate | API 594 dual-plate wafer checks — high-volume pipeline supply |
| Spirax Sarco | Lift, swing | DCV, SG check valves — steam trap bypass and condensate return |
Frequently Asked Questions
What type of check valve is best for pump discharge to prevent water hammer?
Dual-plate wafer check valves with a spring-assist feature are the most common choice for pump discharge where water hammer is a concern. The spring pre-loads the half-plates closed so they react before reverse flow develops, dramatically reducing slam. For large-diameter pump mains (above DN 400), a tilting disc check valve or an axial nozzle check valve are preferred — the tilted open position means the disc has less distance to travel on closure. Avoid large swing check valves on pump discharge without dashpot or counterweight assist.
Can check valves be installed vertically?
It depends on the valve type and flow direction. Lift check valves are designed for vertical installation with upward flow — gravity assists closure. Dual-plate wafer checks with a central spring can be installed in any orientation including vertical. Swing check valves can typically only be installed with flow upward in vertical pipelines — in horizontal flow the disc would hang open. Axial nozzle check valves are orientation-independent. Always check the manufacturer's installation guide for the specific model and orientation.
What does API 594 specify for check valves?
API 594 covers wafer, wafer-lug, and double-flanged check valves in steel (carbon, alloy, and stainless). It specifies design, materials, face-to-face dimensions, testing, and marking requirements. API 594 check valves are manufactured to ASME Class 150 through Class 2500 pressure ratings. The standard is most commonly applied to dual-plate wafer check valves and tilting disc check valves used in process plant and refinery service. For pipeline applications, API 6D is the applicable standard.