Specifying a pneumatic conveyor starts with three binary decisions — dilute-phase vs dense-phase, vacuum vs positive-pressure, and continuous vs batch — because each branch collapses a vendor's catalogue into a handful of eligible models, as shown by Delfin Industrial Vacuums' 2025 product listings on DirectIndustry [S1].
For powders and grains over 100 µm with poor flow characteristics, a dilute-phase electro-pneumatic conveyor with a side-channel blower in the 5.5–15 kW band is the dominant 2025/2026 build pattern, exemplified by Delfin's TECH420E rated 550–2,400 kg maximum load with AISI 304 contact parts and FDA/CE certification [S1]. Where the duty is feeding small stampings rather than bulk powder, the spec map inverts: FIBRO's 2199 series uses vibration-only conveying at 3/10/40/70 kg payloads across 125–160 mm effective width channels, with virtually no air consumption [S3].
Phase Selection: Dilute-Phase vs Dense-Phase vs Fluidized
Dilute-phase conveying operates at high air-to-product ratios and low line pressures, suiting non-fragile powders and grains; dense-phase conveying pushes slugs at low velocity for abrasive, fragile or blended products where segregation is unacceptable, and Delfin offers both as separate PRO/280 and TECH/280 product families on DirectIndustry (2026-06) [S4]. A third regime — fluidization — sits between them: Trelleborg's SCIROCCO II hose vulcanizes a fluidizing membrane into the lower wall of a flexible rubber hose, holding 5–500 kg/h bulk throughput at 2 m/s nominal speed with a 1 kg load ceiling and a mining/vehicle-loading application profile (2026-05) [S2]. The boundary between regimes is set by the material's deaeration time, particle density and tendency to smear, not by vendor marketing labels.
Where a standard pneumatic cylinder or pneumatic actuator is the driving element for valve and diverter actuation, the conveyor's phase dictates the air supply sizing: dilute-phase installations need continuous high-volume blower duty, dense-phase installations need receiver-tank-pulsed delivery, and fluidization systems need only low-pressure aeration, so air-prep and compressor selection must be re-evaluated per phase choice.
Mode Selection: Vacuum (Aspiration) vs Positive-Pressure
Vacuum/aspiration systems pull material through the line and discharge through a filter-separator, which keeps the line under negative pressure and stops dust leaks — the pattern used across Delfin's PRO280E and TECH280E aspiration conveying systems on DirectIndustry (2025-09 onwards) [S1]. Positive-pressure systems push from a feeder through the line and are better for multiple discharge points over long horizontal runs. The TECH420E explicitly markets long-distance dilute-phase powder transport with optional inverter control on its 5.5–15 kW three-phase motor, and is modular so transport power can be added later without replacing the unit (2022-10 spec page, still listed in 2026-06 Delfin catalogue snapshots) [S1][S4].
The fitting and piping train differs sharply between modes: vacuum systems use suction-side pneumatic fittings rated for negative gauge pressure and leak-tight seals at the receiver, while positive-pressure lines need pressure-rated bends, sight glasses and diverter valves sized for the dense-phase slug pressure transient.
Material Properties That Drive the Spec
Four material parameters gate the design: particle size, bulk density, friability and moisture/hygroscopy. The Delfin TECH420E is qualified for powders above 1 µm and "grains with poor flow" that must remain intact [S1], which sets a hard upper limit on conveying velocity to prevent attrition. Trelleborg's SCIROCCO II targets dry powders that fluidize cleanly, so cohesive or moist powders that channel or rat-hole will not convey in this geometry [S2]. The Sower dimensional venturi-type pneumatic transmitter, sold into Chinese OEM assembly lines since at least 2026-05, is described as leak- and blockage-free with "strong transmission ability and long conveying distance" — a claim that depends on the conveyed powder having free-flowing behaviour under venturi suction (2026-05) [S6].
For metallic parts and stampings, none of the bulk-powder rules apply: the FIBRO 2199 series handles 3–70 kg loads by vibrating a channel at low air consumption, designed originally for press shops to move stampings from the tool area to storage containers, and the parts' mass inertia carries them forward on the slow-forward/fast-back stroke (2025-11) [S3]. This is essentially a parts-feeding conveyor, not a bulk-material conveyor, and the selection criteria are payload, channel width and length rather than airflow.
Throughput, Distance and Power Envelope
The 2025/2026 OEM data shows a clear envelope: bulk-powder pneumatic conveyors deliver 5–500 kg/h in light-duty fluidized form (SCIROCCO II at 2 m/s, 1 kg load) [S2] and reach 2,400 kg maximum load in heavy-duty dilute-phase form (Delfin TECH420E) [S1]. Power scales accordingly: light flexible systems run on aeration air at near-zero motor input, mid-range dilute-phase units need 5.5–15 kW three-phase side-channel blowers, and dense-phase industrial lines scale further based on distance, bends and solids-to-air ratio. The ScienceDirect-published Pneumatic Conveying Design Guide (ISBN 9780750654715, 2nd edition, 2025-09 listing) remains the most cited logic-diagram and scaling-parameter reference for matching line configuration to material characteristics [S5].
Distance and routing matter as much as throughput. Flexible hose-based systems like SCIROCCO II can be routed around pillars and through openings where rigid screw conveyors cannot fit, which lowers installation cost in retrofit or confined-space plant builds [S2]. Modular dilute-phase systems like the TECH420E use a side-channel blower to push powder over long horizontal distances, and the modular architecture lets the owner add conveying power in the field rather than replace the unit — a significant total-cost-of-ownership advantage for plants expecting production growth (2022-10 spec still referenced in 2026-06 manufacturer pages) [S1][S4].
Selection Criteria Comparison Across 2025/2026 OEM Builds
Comparing the three reference designs on the criteria that actually drive purchase decisions: Delfin TECH420E wins on raw bulk capacity at 550–2,400 kg max load with 5.5–15 kW power and FDA/CE compliance for food-grade powders [S1]; Trelleborg SCIROCCO II wins on installation flexibility and low power draw for dry free-flowing powders at 5–500 kg/h, with a 1 kg load ceiling that rules it out for any heavy bulk duty [S2]; FIBRO 2199 series is in a different category entirely — vibratory parts feeding at 3–70 kg with near-zero air consumption, sized by channel width (125/140/160 mm) and length (184.5/216/250.5/325 mm) rather than airflow [S3]. The decision tree is therefore: bulk powder at scale → dilute-phase positive or vacuum with side-channel blower; free-flowing powder in confined routing → fluidized flexible hose; small parts or stampings from a press → vibratory pneumatic conveyor. Related reference: see our belt conveyor selection spec map for the mechanical-conveyor alternative when pneumatic conveying is over-specified for the duty.
Limitations, Failure Modes and Maintenance Profile
Dilute-phase conveyors fail in three predictable ways: particle attrition when velocity is set too high for friable product, line blockage at bends when the air-to-product ratio collapses, and filter loading when the receiver-side separator is undersized. Dense-phase systems fail by slug rupture in long horizontal runs and by receiver-tank pressure decay between pulses. Fluidized-hose systems like SCIROCCO II fail by membrane fouling when powders are cohesive, hygroscopic or oily — the fluidizing air simply channels through the powder bed rather than suspending it [S2]. The Delfin TECH420E design mitigates attrition with a "powder integrity preservation" specification and uses a maintenance-free side-channel blower; the FIBRO 2199 sells explicitly on being maintenance-free with very low air consumption (2025-11/2022-10 listings still current) [S1][S3].
Hygiene and contact-material selection are the second constraint layer. AISI 304 stainless steel with glossy interior and satin exterior finish is the Delfin TECH420E baseline for food-grade duty, and CE plus FDA certifications cover EU and US regulatory markets [S1]. Sower's venturi pneumatic transmitter explicitly markets "no dust flying, no leakage or blockage" for contained transfer in assembly-line environments where dust ingress would damage downstream equipment (2026-05) [S6]. Where the conveyed material is a regulated food, pharma or fine chemical, the contact-material certificate chain — not just the conveyor's brand — is the gating spec.
Standards, Sourcing and Vendor Signal Map (2025-09 to 2026-07)
No single ISO or IEC standard governs pneumatic conveyor selection as a unit; instead the design pulls in material-handling codes (ISO 9001 build quality for OEMs like Delfin and Trelleborg), pressure-equipment codes for the receiver vessels, ATEX 2014/34/EU for explosive-dust atmospheres (relevant for any powder above its MEC), and FDA / EU 1935/2004 for food-contact surfaces as cited on the Delfin TECH420E spec sheet (2022-10 product page, still live 2026-06) [S1][S4]. For parts-feeding conveyors in press shops, the relevant compliance set is machine-safety (ISO 12100) plus press-specific guards, not bulk-material codes. The Pneumatic Conveying Design Guide (ScienceDirect, ISBN 9780750654715) remains the most cited logic-diagram reference for conveying-line scaling parameters and remains in active distribution (2025-09 listing) [S5].
Trackable signals for the next 6–12 months: new dense-phase product releases on the Delfin and PRO/280 lines (DirectIndustry listings updated 2026-06) [S4], continued displacement of screw conveyors by flexible fluidized-hose systems in mining and confined-space retrofit builds (Trelleborg SCIROCCO II activity 2026-05) [S2], and growing specification of venturi-type pneumatic transmitters in Chinese OEM assembly lines for dust-free parts feeding (Sower dimensional, 2026-05) [S6]. For buyers comparing pneumatic to mechanical conveying alternatives, the belt conveyor selection spec map is the most directly comparable reference, while sites handling combustible powders should cross-check our air pollution control system cost map for downstream filter and separator sizing.