This article is written for Check Valve used in oilfield API 6A high-pressure flowline, wellhead and manifold service. The product should be confirmed by its real oilfield service position, not only by a short catalogue name. For API oilfield equipment, the useful specification combines pressure rating, nominal size, end connection, service condition, material or seal requirements, and inspection documents.
Check valves, sometimes called one-way valves in field use, are mainly used in high-pressure line systems to isolate well fluids and service fluids and prevent reverse flow in the line. Installed in high-pressure flowlines, the internal flapper closes automatically when reverse flow tends to occur, effectively preventing backflow and maintaining safe, stable operation of the high-pressure system.
Cold working pressure ratings include 10,000 psi (70 MPa) and 15,000 psi (105 MPa). Union nominal sizes include 2" and 3". End connection types include Fig 1002 and Fig 1502, suitable for use with high-pressure manifolds and related high-pressure service lines in oil and gas fields.
Before production, pressure rating, nominal bore, Fig or API flange connection, end orientation and service condition should be confirmed together. A single missing detail can make the part unsuitable for the actual manifold.
Key points to confirm
For Check Valve, we normally recommend confirming the following items before quotation, production or replacement.
- Applicable standard or project requirement: API 6A.
- Working pressure, test pressure, nominal size and bore requirement.
- End connection type, mating equipment, flow direction and installation space.
- Service condition such as standard service, NACE sour service or low-temperature service.
- 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.