· Quantity? What is the material being fed?
· What is the rotary valve size? Is it round or square?
· Is it an airlock only, or airlock feeder?
· What is above the valve? What is below the valve? What is the height clearance?
· What are the pressure measurements above and below the airlock (positive, negative, atmospheric)?
· Temperature above the airlock? Is the temperature ambient below the airlock?
· Is it high, average, or low humidity above the airlock?
· What is the bulk density of the material?
· Is the particulate shape: Pellet, granular, powder, flake, chip, curl, lump, fibrous, etc.? What is the max particle size?
· What flow rate are you looking for?
· Is the material abrasive or corrosive?