Pneumatic Conveying Calculator

Pneumatic conveying moves bulk solids through pipework using an air stream, and the central design question is always the same: how fast does the air need to move so particles stay suspended instead of settling and blocking the line? This calculator estimates that threshold — the saltation velocity — using a simplified form of the Rizk correlation, which scales with pipe diameter, the ratio of particle density to air density, and particle size raised to a small power. It then applies a 1.4x safety factor on top of saltation velocity to get a minimum conveying velocity, and floors the design velocity at 12 m/s (a standard minimum for dilute-phase systems) so the recommendation never drifts into blockage-risk territory. From that design velocity and the pipe's cross-sectional area, the calculator derives air mass flow, then divides your solids mass flow by it to get the solids loading ratio — the single number that determines whether your system is dilute phase (ratio under 15, high velocity, lower pressure) or dense phase (ratio over 15, lower velocity, higher pressure, gentler on friable material).

Total pressure drop sums an air-only friction term (using a fixed Darcy friction factor of 0.02, with bends converted to equivalent straight-pipe length at 7.5 pipe diameters each), plus a solids term covering acceleration, added friction proportional to the loading ratio, and the lift penalty for any vertical rise. Blower power then follows from air volume flow times total pressure drop over blower efficiency. Because saltation velocity, friction factors, and bend-loss assumptions are all simplified engineering correlations rather than measured system data, use these results for preliminary system sizing and validate against vendor test data or a detailed pneumatic conveying design guide before specifying final pipe diameter and blower capacity.