How do feeders control the flow rate and what are the three main challenges all gravimetric feeders must meet? What's the difference between gravimetric and volumetric feeding, and continuous and batch opertions?
Processing a plastic from its purely chemical origins all the way to its final form as a useful product involves a host of operations, not the least of which is tailoring its various properties, attributes and characteristics to meet exacting end-product requirements.
Much of this tailoring is, in one way or another, achieved through the use of feeders to control the introduction of additional ingredients such as additives, colorants, fillers, stabilizers, lubricants, etc. according to specified formulation or recipe proportions.
Before focusing on the principles behind feeder design and operation, it’s important to understand just what feed rate means (Feed Rate Basics), what every gravimetric feeder needs to perform its function (The Gravimetric Feeder Triangle), and the two basic approaches to blending or proportioning (Blending & Proportioning).