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. The batch is then mixed and made available for further processing as required.
In continuous blending, feeders continuously discharge each ingredient at a rate based on the ingredients’ required proportion in the formulation’s desired total throughput rate.
Depending on the application’s specific requirements, a combination of these approaches can be involved such as, for example, the separate preparation of select minor additives in masterbatch formulation prior to its introduction in a continuous, end-product extrusion line where other, more major additives may be introduced as well.
Owing to the diversity of process need, the number of possible blending configurations is extensive, and each application verges on near uniqueness when account is taken of all the materials, rates, ranges, proportions and other details and variables involved.
For a more detailed introduction to the principles and practices of batch and continuous blending along with their relative advantages and limitations, see the Batch Blending and Continuous Blending screens in the following Core Operating Principles section.