Tips to finding the right mixer for your application.
We wrote this article for Powder Bulk and Solids Magazine and first appeared there.
Industrial mixing equipment is a major investment for any production facility, so the temptation is great to choose a processor with the fastest throughput, typically achieved by continuous mixing. However, the trade-offs between continuous and batch mixing need to be carefully understood before making the choice. In fact, for most applications, it’s possible to implement continuous process batch control, which combines the best of batch and continuous mixing.
This article reviews the different types of mixing, advantages and disadvantages of each, and gives specific considerations that every processor should take into account when making the choice between continuous, batch, or continuous process batch control mixing.
Understanding each type of mixing
Firstly, it’s important to understand the differences between each type of mixing.
Continuous mixing is a process by which materials are constantly flowing through controlled feeds into the mixer, being mixed for a short period of time (seconds or minutes), and then flowing through discharge. Continuous mixing provides high throughput and low energy use comparatively to batch mixing. Continuous mixers are mainly used for dry materials. Certain types of slurries and viscous materials can also be processed in continuous mixers if the mixer is fitted with the proper customizations, such as a special agitator to control flow.
Batch mixing, similarly, takes in materials from feeders or hoppers, and mixes them for a longer period of time. At the end of the mixing process, the mix exits the machine, and then the machine is ready for either cleaning or for the next batch. Batch mixing gives high precision and control of the exact makeup of the mixture. Full control of what goes in gives full control of what comes out.
Continuous process batch control mixing is a batch process that improves the speed of batch mixers. In continuous process batch control, the hoppers are filled while the mix is in the mixer, and then as soon as the mixer is emptied, the next batch is immediately fed into the mixer. This process combines the precision of batch with some of the speed of continuous mixing. Manufacturers who want high-throughput and high accuracy should be considering this option. Continuous process ensures the equipment is at maximum capacity, while providing precision control through batch loading.
Manufacturers are presented with numerous choices when it comes to process mixers for the chemical industry. Some mixers last 20, 30, 40 years or more. Deciding on an investment that is flexible and durable enough to ...