Check Valves
A check valve — also called a non-return valve — allows flow in one direction only. When flow reverses, the valve closes automatically, preventing backflow that would damage pumps, compressors, or upstream equipment. Unlike gate valves and globe valves, check valves require no operator action — they respond automatically to flow direction.
What Check Valves Do
In oilfield and production facility service, check valves protect:
- Pumps — preventing backflow through the pump when it stops
- Compressors — preventing reverse flow into compressor cylinders
- Injection lines — preventing produced fluid from flowing back into injection pumps
- Flowlines — preventing backflow between wells in a common manifold
- Chemical injection — preventing produced fluid from contaminating chemical tanks
Correct check valve selection for the fluid type, flow rate, and pressure drop is critical for reliable non-return function.
Product Range
WNS Lowery supplies a full line of carbon steel and stainless steel check valves for oilfield and industrial service. All valves are 100% American-made and available with Z-PEX coating for heat resistance to 550°F and resistance to corrosive chemicals.
Swing Check Valves
Swing check valves use a hinged disc that swings open under forward flow and closes by gravity and backpressure when flow stops. They have low pressure drop in the open position and are well suited to liquid service in horizontal pipe runs.
Ball Check Valves
Ball check valves use a ball that lifts off its seat under forward flow and reseats under backpressure. They are suitable for viscous fluids and slurry service where a swing disc might become fouled.
Key Specifications
| Parameter | Details |
|---|---|
| — | — |
| Types | Swing check, ball check |
| Body materials | Carbon steel, stainless steel |
| Coating option | Z-PEX — to 550°F, corrosion resistant |
| Elastomers | Multiple options for fluid compatibility |
| End connections | Threaded, flanged |
| Origin | 100% American-made |
Why Source Through Proxima
Proxima stocks WNS Lowery check valves in standard oilfield sizes for fast delivery across Azerbaijan and the Caspian region. We supply valves with full material certifications.
Frequently Asked Questions
Q: What is the difference between a swing check and a ball check valve?
A swing check uses a hinged disc — low pressure drop, best for clean liquids in horizontal lines. A ball check uses a ball — better for viscous fluids, slurries, or vertical pipe runs where a swing disc may not close reliably.
Q: Can check valves be used for gas service?
Yes. Both swing and ball check valves are available for gas service. Specify the fluid and operating pressure when ordering to ensure the correct seat material and pressure class.
Q: What does the Z-PEX coating provide?
Z-PEX is a polymer coating applied to the valve body that provides heat resistance to 550°F and resistance to a wide range of corrosive chemicals. It extends service life in aggressive environments without requiring stainless steel construction.
