Eccentric Pipe Fitting Factory

Eccentric Pipe Fitting – Managing Flow Alignment in Inclined Pipelines

Introduction
An eccentric pipe fitting is a specialized component in which the centerlines of the inlet and outlet differ vertically, creating an offset. This design is crucial when pipelines need to remain level at one side—often to avoid air accumulation in pumps or to maintain proper drainage. Hebei Longrun Pipeline Group Company produces eccentric fittings in various sizes and materials to meet the precise alignment requirements of fluid handling systems.

Material Selections

Carbon Steel (A234 WPB): Standard for general industrial pipelines.

Alloy Steel (A234 WP5/WP9): For elevated temperature and pressure applications.

Stainless Steel (A403 WP316, WP321): For corrosion-prone or sanitary services.

High-Alloy Grades: Duplex and Super Duplex for demanding chemical or marine environments.

Design Characteristics

Top-Offset vs. Bottom-Offset:

Top-Offset: Useful to maintain top-of-pipe alignment when joining to equipment or valves.

Bottom-Offset: Ensures bottom-of-pipe alignment for gravity drainage or to avoid air pockets.

Angle Options: Standard 90° elbows are common; custom-angle eccentric bends (e.g., 45°) are available.

Radius Variations: Long-radius (1.5 D) fittings minimize pressure loss, while short-radius (1 D) conserve space.

Manufacturing Workflow

Mandrel Bending or Hot Induction: Pipes are bent over a mandrel or heated induction coil to achieve the eccentric curvature with uniform wall thickness.

Extrusion/Forming: For larger diameters, a seamless blank may be extruded and machined into the eccentric shape.

Heat Treatment: Normalization refines microstructure and relieves stresses introduced during forming.

Machining: Ends are faced or beveled for welding; key dimensions (offset distance, angle) are verified.

Inspection: Ultrasonic wall thickness mapping and dimensional checks ensure consistency with design tolerances.

Specifications

Size Range: DN 15 to DN 1200 (½″ to 48″) and beyond.

Pressure Classes: ANSI Class 150–1500.

Standards Compliance: ASME B16.9, EN 10253, ISO 1127.

Applications

Pump Suction Lines: Bottom-offset elbows prevent air entrapment and ensure continuous fluid supply.

Drainage Systems: Bottom-aligned branches guarantee complete line drainage in sanitary and process systems.

Heat Exchanger Connections: Top-offset fittings maintain level inlet/outlet nozzles to facilitate installation.

Chemical Injection: Offset fittings accommodate unequal pipeline elevations without disrupting flow balance.

Installation Guidance

Orientation Verification: Confirm offset direction matches system design to prevent unintended level changes.

Welding Preparation: Clean cut ends and apply proper bevel angles; follow qualified welding procedures.

Support and Anchoring: Provide supports at neutral points to reduce stress on the eccentric joint.

Maintenance Notes
Periodic inspection of weld seams and wall thickness is essential, particularly where erosion or corrosion may occur. Replace fittings showing excessive wear or deformation.

Conclusion
Hebei Longrun Pipeline Group Company’s eccentric pipe fittings offer precise flow alignment solutions for piping systems requiring level continuity on one side. Through careful material selection, controlled manufacturing, and strict testing, these fittings ensure dependable performance in varied industrial contexts.