PT ZONE: Feeding Fundamentals
4.2.1.2 – Vol/Grav Art In the continuous formulation of plastics the primary purpose of feed rate control is to achieve consistently accurate proportioning of recipe components (resin and required additives) prior to pelletization (in compounding) or end-product forming operations.Feeders produce a precise and controllable discharge rate for the material they are designed to handle. More (+)
The Gravimetric Feeding TriangleAll gravimetric feeders, regardless of type or operating principle, must meet three core requirements, here represented as the three sides of a triangle. (4222 placeholder)• Material Handling: Condition the material to minimize density variation (as required), and then produce a volumetrically uniform discharge stream• Weighing: Continuously perform accurate, high-resolution weight measurements to form the basis for subsequent control actions• Control: Continually determine and execute appropriate control actions to achieve or maintain the required gravimetric discharge rateEach side of the feeding triangle presents its own unique array of challenges, and each dynamically interacts with the other two. More (+)
MOST RECENT CONTENT: Feeding Fundamentals
Blending & Proportioning
6/14/2011Plastics Technology
Basically, there are only two main approaches to ingredient proportioning or blending: batch and continuous.In batch blending, required quantities of each ingredient are weighed out either manually or by automated batching systems according to desired batch size and recipe proportions.
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OVERVIEW:
Feeding Fundamentals
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).
