Pneumatic Conveying Bend
Technology and Engineering

Understanding Bend Geometry

An elbow redirects the carrier gas and the conveyed particles, but the two phases do not necessarily follow identical trajectories. A particle may impact the wall, slide through the bend, bounce back into the stream or strike downstream pipework. This is why changing a bend’s shape affects more than the occupied installation space.

For engineering comparison, start by distinguishing flow-path geometry from wear-protection construction. PneuBend’s launch families cover both: pocket, sweep and segmented bends describe a change in direction, while basalt lining, ceramic lining and tungsten carbide hardfacing describe ways to protect a pipe-bend surface.

Pocket, Sweep and Segmented Flow Paths

Pocket / Material-Cushion

A compact cast chamber contains a region intended to accumulate conveyed solids under suitable conditions. It is specified using connection offsets and envelope dimensions rather than a circular centerline radius. The pocket may also retain product after shutdown. Pocket elbows.

Sweep

A continuous curve has a measurable centerline radius. Radius influences available installation space, particle-wall contact and possible wear. The same DN can have several approved fixed radii. Sweep elbows.

Segmented

Straight lengths joined at miter angles approximate the required turn. The drawing must disclose segment count, joint positions and actual envelope rather than treating the design as a continuously curved pipe. Segmented elbows.

Wear Protection: Basalt, Ceramics and Hardfacing

A basalt or ceramic lining introduces a product-contact material with its own thickness, joints and retention scheme. A tungsten-carbide-containing weld overlay is deposited on a compatible metal substrate. These wear systems address different mechanisms and have distinct inspection requirements. A material’s hardness does not by itself predict whole-assembly service life.

Curvature Radius Versus Installation Envelope

For smooth sweeps, a nominal 90° circular arc has a centerline extension related to its CLR. Real finished envelope includes tangents, flanges and any reinforcement. For pocket or segmented elbows, a simple sweep-radius comparison may hide important differences. See radius and dimension guide.

Material Selection and Finished Bore

Body material, liner material and end-connection standard are independent specifications. For lined bends, the finished clear bore may be notably smaller than the metal housing bore. Specify the required throughput and piping interface before selecting liner thickness.

Connection Standards and Pressure Ratings

DN, NPS and actual pipe OD can be confused. Similarly, an EN PN drilling pattern or ASME Class bolt circle does not establish the pressure rating of the complete elbow. Review flange facing, bolt pattern, seals and product body together. Connection guide.

Product Families Versus General Industry Technologies

Our product catalog presents the six planned PneuBend launch families. Engineering articles may discuss other industry approaches for comparison, but that does not mean those products are currently offered by Polimak. Further PneuBend families can be added after design and manufacturing approval.

Engineering Support and RFQ

Share the material, pipe dimensions, angle, conveying conditions, project stage and principal failure or quality concern. We can then identify candidate families and missing data for an approved specification. Selection guide · Request a quote.