This article addresses check valves used in high-pressure oilfield flowlines and manifolds. Selection must define CWP, nominal bore, flow direction, end connection, service environment, materials/seals and required test documentation.
A check valve is a non-return device, not a positive-isolation valve. Its flapper or dart closes automatically when flow reverses, helping prevent backflow; required cracking pressure, pressure drop, orientation and reverse-leakage acceptance criteria must be specified.
The displayed product range includes 2 in and 3 in union-end configurations from 6,000 psi to 20,000 psi, depending on valve type and end connection. Verify the CWP and exact Fig profile for each ordered model.
In field layouts, the first question is where the component sits in the pressure path and what equipment it must connect to. The answer affects connection direction, pressure class, access for operation and future maintenance.
Key points to confirm
For Check Valve, we normally recommend confirming the following items before quotation, production or replacement.
- Applicable manufacturer/project product specification and end-connection drawing; apply API Spec 6A only where documented for the ordered model or interface.
- Working pressure, test pressure, nominal size and bore requirement.
- End connection type, mating equipment, flow direction and installation space.
- Service condition: standard, low-temperature or sour service; for sour service, provide the environmental limits needed for NACE MR0175/ISO 15156 material selection.
- Required documents such as MTC, pressure test report, NDT report and third-party inspection.
Field use and inspection
Check Valve should be checked as part of the complete high-pressure system. Sealing surfaces must be protected, connections should be clean before make-up, and the product should not be forced into alignment by side load, hammering or pulling. If leakage, abnormal operation or pressure-test instability occurs, the model, pressure, medium, photos and test conditions should be recorded for technical review.
Information for quotation
For new projects, please provide the line layout, operating pressure, medium, temperature, connection standard and document requirements. For replacement work, old-part photos, nameplate or body markings, end-connection close-ups and installation position help us confirm the correct Check Valve quickly.