Eccentric Reducer Pipe Fitting | Prevents Sediment Buildup

An eccentric reducer pipe fitting is a diameter transition connector. It features two ends with centers on different axes to maintain a flat pipe bottom. Engineered specifically for horizontal piping systems, this design effectively prevents medium stagnation, cavitation and solid deposition issues.

The eccentric reducer pipe fitting enables air bubbles or solid particles in the fluid to discharge continuously along with the main flow, greatly reducing the risks of pipeline blockage and corrosion.

Carbon steel (ASTM A234 WPB), stainless steel (304/316L), alloy steel (ASTM A335 P11/P22), duplex steel (2205)

Cold/hot extrusion, forging (for eccentric swage reducer), welding (for eccentric weld reducer)

ASME B16.9 (Butt Weld), MSS SP-43 (Light Wall), DIN 2616

Nominal Diameter: 1/2″ × 1/4″ to 48″ × 36″

Typical Specification: 6″ x 2″ eccentric reducer (Outer Diameter: 168.3mm→60.3mm, Length: 152mm)

Note: The welding bevel of eccentric weld reducer is processed in accordance with ASME B16.25; the eccentric swage reducer is integrally formed with seamless forgings.

The flat bottom is achieved by keeping the bottom surfaces of the large end and small end on the same horizontal plane. This geometric configuration of eccentric reduce ensures no liquid accumulation at diameter transition sections during long-distance horizontal transportation.

Q1: What are the core differences between eccentric reducers and concentric reducers? How to make a proper selection?

A: A concentric reducer features aligned central axes at both ends, suitable for vertical pipes and risers. In contrast, the eccentric reducer pipe fitting maintains a horizontal pipe bottom and is exclusively designed for horizontal pipelines. The eccentric type is mandatory for horizontal pipelines conveying liquid and solid particles or requiring cavitation avoidance.

For instance, eccentric reducers with flat bottoms facing downward shall always be adopted for horizontal sections at pump inlets to prevent gas accumulation and cavitation.

Q2: What key points should be noted during the welding installation of an eccentric weld reducer?

A: First, confirm the installation direction of the reducer, ensuring the Flat Bottom is placed at the pipeline base. Second, verify that the bevel angle and root face comply with the process piping code ASME B31.3. For specifications with a large reduction ratio such as the 6″ x 2″ eccentric reducer, GTAW backing welding combined with SMAW filling welding is recommended, and 100% Radiographic Testing (RT) shall be conducted to eliminate incomplete fusion defects inside the pipe.