Rotary feeder selection should be based on the material and the process condition. A rotary airlock valve used under a dust collector, a silo outlet or a pneumatic conveying line may require different checks even when the capacity looks similar.  Step 1: define the material  Start with material name, particle size, bulk density, moisture, abrasiveness, stickiness and temperature. These properties affect rotor pocket filling, sealing, wear and discharge stability.  Step 2: confirm capacity  Capacity selection needs the required throughput and the operating pattern. Continuous feeding, batch discharge and intermittent unloading may require different speed and volume choices.  Step 3: check pressure condition  If the valve works as an airlock feeder, pressure difference and air leakage matter. In pneumatic conveying systems, sealing and rotor clearance should be checked together with capacity.  Step 4: choose body and rotor configuration  The suitable configuration depends on material contact requirement, wear condition, temperature and cleaning demand. Options may include cast iron, stainless steel, square flange, circular flange, quick disassembly, high temperature or coated contact surfaces depending on the application.  Step 5: confirm installation data   Inlet and outlet flange size.  Available installation height.  Drive side and motor orientation.  Connection standard and existing equipment layout.  Maintenance access around the valve.   Related FUWEI pages  For capacity and dimensions, use  Rotary Valve Sizing Calculator, Dimensions & Capacity . For common operation issues, see  Rotary Airlock Valve Repair & Troubleshooting Guide . Product options can be checked from  ZGF / GF Series Rotary Airlock Valve  and  ZGFWF / DN Series Rotary Airlock Valve .  Selection note  For a practical selection, send material data, capacity, pressure condition, temperature and installation dimensions. FUWEI can then help compare suitable rotary feeder configurations.