Pneumatic Conveying Glossary
Plain-language definitions of the terms engineers, plant managers and maintenance teams use to design, run and troubleshoot pneumatic conveying systems. Pick a letter to jump to that section.
Pneumatic conveying abrasion
Wear from sustained sliding or rubbing contact between conveyed material and a pipe or elbow wall, producing gradual, even material loss.
Learn more: How to minimize elbow wear
Abrasion resistant elbows
Elbows built or lined with hardened materials to withstand sustained sliding/rubbing wear from conveyed material, extending service life over standard steel or aluminum elbows.
Learn more: Abrasion-resistant elbow options
Pneumatic conveying air velocity
The speed of the air stream moving material through the line; a key design variable that must balance conveying reliability against wear and product degradation.
Learn more: How to calculate air velocity
Pneumatic conveying angel hair
A specific, fine form of streamer contamination in plastics conveying, caused by the same friction/heat mechanism as streamers.
Learn more: Conveying for plastics applications
Centerline radius elbow
An elbow classified by its centerline radius (CLR), the radius of the bend measured to the pipe’s centerline, expressed as a multiple of pipe diameter.
Learn more: What a centerline radius is and how it’s measured
Ceramic coated elbows
Elbows with an exterior coating of either a ceramic bead compound, Ceram-Back®, or with a welded box over the back of the elbow that contains cast ceramic tile, a flat-back cast ceramic elbow.
Learn more: A guide to ceramic coated elbows
Ceramic interior lined elbows
Elbows with an interior wear surface lined in ceramic tile or castable ceramic, used to resist high-abrasion materials.
Learn more: Ceram-Back® ceramic-lined elbows
Dense phase pneumatic conveying
A conveying method using low velocity and higher line pressure to move material as slugs or a moving bed, generally reducing wear and product degradation.
Learn more: Dense phase vs. dilute phase conveying
Dense phase vs dilute phase conveying
A comparison of the two primary conveying methods: dense phase moves material at low velocity/high pressure as a moving bed, while dilute phase moves material fully suspended in a high-velocity air stream.
Learn more: Dense phase vs. dilute phase conveying
Pneumatic conveying design mistakes
Common system design errors (undersized lines, incorrect velocity, poor elbow selection or placement) that accelerate wear, increase pressure drop, or cause chronic operational problems.
Dilute phase pneumatic conveying
A conveying method using a high-velocity, lower-pressure air stream to fully suspend material in transit, simpler to install but harder on components.
Learn more: Dense phase vs. dilute phase conveying
Pneumatic conveying elbow blowout
A sudden failure, typically a hole worn through the elbow wall, resulting in material loss, air leakage, and unplanned downtime.
Learn more: How to minimize elbow wear
Pneumatic conveying elbow erosion
Wear caused specifically by particles striking the elbow surface at an angle, typically concentrated at the elbow’s outer radius.
Learn more: How to minimize elbow wear
Pneumatic conveying elbow failure
The point at which accumulated wear compromises an elbow’s structural integrity, requiring replacement before a breach occurs.
Learn more: How to minimize elbow wear
Pneumatic conveying elbow for cement
Elbow selection guidance specific to cement, which combines fine particle size with notable abrasiveness on elbow walls.
Learn more: Conveying for heavy industry
Pneumatic conveying elbow for fly ash
Elbow selection guidance specific to fly ash, a fine and extremely abrasive material that requires heavy-duty wear-resistant elbow options.
Learn more: Conveying for heavy industry
Pneumatic conveying elbow for food
Elbow selection guidance specific to food-grade applications, where contamination control and sanitary construction are as critical as wear resistance.
Learn more: Conveying for food and pet food
Pneumatic conveying elbow for grain
Elbow selection guidance specific to grain, balancing abrasion resistance with product integrity and contamination control.
Learn more: Conveying for grain
Pneumatic conveying elbow for plastic pellets
Elbow selection guidance specific to plastic pellets, where the primary concern is minimizing degradation (streamers/fines) rather than elbow abrasion.
Learn more: Conveying for plastics applications
Pneumatic conveying elbow for silica sand
Elbow selection guidance specific to silica sand, one of the most abrasive common bulk materials, typically requiring heavy-duty wear-resistant elbows.
Learn more: Conveying for heavy industry
Pneumatic conveying elbow radius
The dimension of an elbow’s bend (commonly expressed via centerline radius) that determines how sharply the airflow changes direction.
Learn more: What a centerline radius is and how it’s measured
Pneumatic conveying elbow selection
The process of choosing an elbow’s degree, radius, wall construction, method of connection, and material based on conveying velocity, material abrasiveness, pressure requirements, and application constraints.
Learn more: A guide to selecting pneumatic conveying elbows
Pneumatic conveying elbow wear
The progressive loss of elbow wall material from abrasion and/or erosion during conveying, the primary driver of elbow replacement frequency.
Learn more: How to minimize elbow wear
Pneumatic conveying elbows
Curved pipe or tube fittings that redirect the flow of material and air within a pneumatic conveying line, typically the highest-wear component in the system due to particle impact at the bend.
Learn more: Browse pneumatic conveying elbows
Pneumatic conveying fines
Small broken particles generated when conveyed material fractures during transport, typically from particle-to-particle or particle-to-wall impact.
How to reduce pneumatic conveying elbow wear
Methods for extending elbow life, including controlling conveying velocity, selecting appropriate radius and wear-resistant materials, and correcting system design issues that concentrate wear.
Learn more: How to minimize elbow wear
Pneumatic conveying line plugging
A blockage in the conveying line caused by material settling or accumulating, commonly due to insufficient velocity, moisture, or a damaged component.
Long radius vs short radius elbow
A comparison of elbow bend geometries: long-radius elbows change direction gradually with lower wear intensity but a larger footprint, while short-radius elbows are compact but concentrate wear over a smaller area.
Learn more: What a centerline radius is and how it’s measured
Pneumatic conveying pressure drop
The loss of air pressure as it travels through a system’s lines, elbows, and components; abnormal pressure drop can indicate a blockage, undersized line, or excessive bends.
Pneumatic conveying product degradation
Physical damage (breakage, fines generation) to the conveyed material from impact against elbows, line walls, or other particles during conveying.
Rotary airlock air leakage
Air that bypasses the rotor pockets through worn or excessive clearances, reducing the conveying air available to the line and lowering system efficiency.
Learn more: Rotary airlocks
Rotary airlock clearance
The engineered gap between the rotor tips/end plates and the housing; too tight causes rubbing wear, too loose causes air leakage.
Learn more: Rotary airlocks
Rotary airlock for pneumatic conveying
The specific use case of a rotary airlock valve as a metering/sealing device feeding material into (or discharging it from) a pneumatic conveying line.
Learn more: The purpose of a rotary airlock
Rotary airlock maintenance
Routine inspection and servicing of an airlock’s seals, clearances, bearings, and rotor condition to prevent leakage and unplanned failure.
Learn more: Rotary airlocks
Rotary airlock troubleshooting
The process of diagnosing airlock-related symptoms (reduced feed rate, leakage, unusual noise, or material buildup) to identify wear, clearance, or mechanical issues.
Learn more: Rotary airlocks
Rotary airlock valve
A rotating vaned device that meters bulk material into or out of a pneumatic conveying line while maintaining a pressure or vacuum seal between the process and atmosphere.
Learn more: The purpose of a rotary airlock
Rotary airlock valve wear
Deterioration of a rotary airlock’s rotor tips, end plates, or housing from abrasive material contact, leading to increased clearance and air leakage over time.
Learn more: Rotary airlocks
Pneumatic conveying streamers
Thin, stringy plastic fragments generated when pellets are sheared or melted by frictional heat against elbow or line walls.
Learn more: Conveying for plastics applications
Pneumatic conveying system blockage
A broader term for any obstruction interrupting material flow through the system; treated as the same underlying issue as line plugging.
Pneumatic conveying system components
The individual parts that make up a conveying system, including elbows, rotary airlocks, diverters, line fittings, and lump breakers.
Learn more: The components of a pneumatic conveying system
Pneumatic conveying system design
The engineering process of specifying line routing, diameter, velocity, pressure, and component selection to reliably convey a given material.
Learn more: The components of a pneumatic conveying system
Pneumatic conveying system maintenance
A scheduled program of inspecting and servicing airlocks, elbows, lines, and other wear components to prevent unplanned failures.
Pneumatic conveying system troubleshooting
The diagnostic process of identifying the root cause of conveying problems (wear, plugging, pressure loss, leakage) by isolating the weak point in the system.
Pneumatic conveying velocity calculation
The engineering calculation used to determine the appropriate air velocity for a given material, line size, and conveying phase.
Learn more: How to calculate air velocity
Pneumatic conveying wear
The general term covering all material loss mechanisms (abrasion and erosion) affecting elbows and lines during conveying.
Learn more: How to minimize elbow wear
Wear resistant elbows
A general category of elbows engineered (via lining, hardened alloy, or replaceable wear components) to resist abrasion and erosion longer than standard elbows.
Learn more: Wear-resistant elbow options
Not sure which elbow fits your line?
Tell us about your material, velocity and layout, and Progressive Products can help match the wear solution to the application.