Pneumatic Conveying Elbow
Frequently Asked Questions

Product and Geometry Questions

What is the difference between a pocket elbow and a sweep elbow?

A pocket elbow redirects material through a compact chamber intended to develop a local cushion of conveyed solids in suitable duty. A sweep changes direction along a continuous curved pipe with a definable centerline radius. They should be compared on installed dimensions, wear, pressure demand, cleaning and product condition—not their appearance alone.

Is the PneuBend compact flanged elbow a separate product type?

No. It is a pocket / material-cushion elbow configuration. The launch family includes 45° and 90° cast flanged versions and selected cast materials.

Why offer segmented bends as well as continuously bent sweeps?

Segmented bends are fabricated from straight mitered sections and may suit geometries or fabrication constraints that differ from smooth bending. Their internal joints can influence wear and flow, so they are not interchangeable without evaluation.

Are basalt, ceramic and tungsten carbide three geometries?

No. They are wear-protection constructions or contact surfaces. A lined or hardfaced bend must also have an approved physical geometry, such as a smooth sweep or segmented route.

Radius and Diameter Questions

Which diameters are planned for PneuBend?

Pocket elbows are proposed from DN50 to DN300. The five pipe-based families are proposed from DN50 to DN400. Manufacturing feasibility and actual material/connection combinations require confirmation.

Can I order several radii for one diameter?

That is the intention for the pipe-based families. The published candidate schedule provides compact, standard and extended CLR choices by DN. The radius must be approved for the selected construction; a pocket elbow has no conventional CLR.

Does DN100 mean exactly 100 mm inside diameter?

No. DN is a nominal designation. Actual pipe OD, wall thickness and any liner thickness determine the finished bore. Provide those dimensions on the enquiry.

Are NPS and DN directly interchangeable?

No. They are related nominal size series but not dimensional specifications. A pipe’s actual outside diameter and schedule must be verified.

Materials and Linings

What metal materials are planned?

Pocket castings: cast carbon steel, cast aluminium and 304-type or 316-type cast stainless steel. Pipe-based designs: carbon steel, AISI 304 and AISI 316. Exact grade certificates and configuration availability are established in the quotation.

Are cast 304 and cast 316 the same as wrought stainless pipe?

Not exactly. Casting specifications use corresponding cast alloy grades, which may be identified as CF8 (304-type) or CF8M (316-type) where approved. The approved material certificate governs.

Is ceramic-lined the same as ceramic-backed?

No. In a ceramic-lined bend, ceramic is part of the initial internal contact surface. In a ceramic-backed design, external ceramic reinforcement supports a metal-based contact path or provides later protection. PneuBend’s launch page concerns internally ceramic-lined pipe bends.

Does a thicker lining always improve wear life?

No. Liner integrity, support, particle impact, joints and a suitable finished bore matter. Excess thickness can reduce flow area or make a geometry impractical.

Is a tungsten carbide overlay appropriate for every steel grade?

No. Overlay process, composition, dilution and thermal effects must be qualified for each substrate. The initial product program lists several candidate base metals but does not promise every coating combination without review.

DIN/ANSI Connections

Which connection types are proposed?

Pocket elbows are flanged only, with applicable European and American patterns. Pipe-based bends may use straight pipe ends, EN/DIN-pattern flanges or ANSI/ASME-pattern flanges.

Does PN16 or Class 150 automatically mean the entire elbow is rated for that pressure?

No. A flange pattern or class designation alone does not certify the complete housing, liner, welds, seals or service temperature. Request the actual assembly operating envelope.

Pressure, Temperature and Installation

Which bend has the lowest pressure drop?

No universal answer is defensible. Compare candidate designs at the same conveyed material, throughput, gas conditions and installation arrangement.

Can a pocket elbow be used for frequent product changeovers?

Possibly, but the retained material and cleaning process require specific validation. If cross-contamination limits are stringent, disclose them before selecting a pocket geometry.

Can I select a bend solely from nominal diameter and angle?

No. Specify OD, wall, finished bore, radius or pocket envelope, connection type, material, operating pressure/temperature and the conveyed solid. Unknown data can be identified for follow-up.

Replacement and Ordering

What should I send for a worn-out elbow replacement?

A photo in place, close-up of wear, any nameplate, current dimensions and flange/pipe measurements, conveying material, pressure regime and service life. The downstream pipe photograph can be especially useful.

Do the provisional radius and material tables constitute a final specification?

No. They are a draft launch catalog. Only an approved technical offer and drawing confirm the material grade, dimensions, buildability and allowable operation for a particular order.

Still have questions? Contact engineering or configure an RFQ.