The airlock rotor is the rotating internal component of a rotary airlock (rotary valve), consisting of a shaft fitted with several pockets or vanes arranged radially, which rotates within a closely fitted housing to meter material through the valve while limiting air leakage between the inlet and outlet sides. The close clearance between the rotor's outer edges and the surrounding housing is what allows the airlock to maintain a partial air seal even as material is continuously metered through.

Rotor clearance increases gradually as the unit wears, particularly when handling abrasive materials, and this growing clearance is the primary mechanism by which an airlock's sealing performance degrades over time — eventually allowing enough air bypass to noticeably affect the efficiency of the pneumatic conveying system it serves.

Rotor vane material and design vary depending on the application: steel vanes offer good durability for general-purpose use, while some designs incorporate replaceable tip strips made from a softer or more flexible material, allowing the sealing edge to be renewed without replacing the entire rotor assembly, extending the practical service interval between full rotor replacements.

Pocket count and rotor diameter together determine the volume of material delivered per revolution, which is a key specification when sizing or selecting a replacement rotor — rotors with more, smaller pockets generally provide finer metering resolution, while fewer, larger pockets favor higher maximum throughput at the cost of somewhat coarser control over delivery rate.

Replacement rotors, along with wear-resistant tip strips or coatings in some designs, are common spare parts stocked by feed mills operating pneumatic conveying systems, and rotor condition is typically assessed through periodic inspection of clearance and visible wear patterns, often using feeler gauges to measure actual clearance against the manufacturer's specified tolerance.

In abrasive service — handling minerals, screenings or other hard, gritty materials — some operations choose hardened or surface-coated rotors specifically to extend service life, accepting the higher initial cost of the upgraded component in exchange for reduced replacement frequency and less associated downtime for airlock maintenance.