Rotary Valves Frequently Asked Questions

It transfers bulk solids between process stages and may provide controlled discharge, volumetric feeding, or an airlock between zones at different pressures.

A drop-through valve discharges material through its lower opening. A blow-through design introduces conveying air through the rotor area to help move material directly into a pneumatic conveying line.

No. Operating clearances permit some leakage. The amount depends on pressure differential, design, clearances, wear, speed, and whether rotor pockets contain material.

It can provide volumetric feeding, but accuracy depends on stable pocket filling, material bulk density, speed, pressure effects, and design. Higher-precision dosing may require a dedicated feeder or feedback control.

Possible causes include oversized particles, foreign objects, product buildup, insufficient clearances, thermal expansion, bearing or drive problems, and unsuitable rotor geometry. Isolate the equipment before inspection.

Capacity depends on usable pocket volume, rotor speed, filling efficiency, material bulk density, and operating conditions. Manufacturer calculations should use representative material and system data.

Potential measures include lower speed, suitable construction materials, wear-resistant surfaces, replaceable wear parts, optimized clearances, and preventing unnecessary pressure or material loading.

Inspection frequency should follow the manufacturer guidance and site risk assessment, accounting for duty cycle, material abrasiveness, temperature, pressure, and consequences of failure.

A suitable design may be used, but cleanability, materials, seals, surface finish, retention points, inspection access, and required documentation must be verified for the exact application.

Identify combustible-dust hazards, hazardous-area classification, temperature limits, ignition risks, pressure conditions, isolation strategy, and applicable site or regulatory requirements.

Bridging can result from cohesive material, hopper geometry, compaction, moisture, poor venting, or an inlet that does not match the flow pattern. The entire hopper-valve interface should be assessed.

Testing is valuable when flow behavior, degradation, abrasion, leakage, pocket filling, or required throughput cannot be predicted reliably from existing representative data.