Selecting Size Reduction Equipment 1790

Thomas E. Warne
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While many different types of size reduction equipment exist there is one common truth: choosing the right machine is a combination of both art and science. Factors such as capital cost, operational costs, and energy consumption must be weighed along with other less obvious topics such as noise level or the amount of dust produced.

Once the type of machine is selected the next step is to determine the proper sized unit, and best configuration of that machine to achieve optimum performance. Buying an off-the-shelf model will seldom meet your needs and you may face significant retrofitting costs in attempting to increase performance.

My expertise lies primarily in impact milling equipment such as hammer mills and lump breakers. Let’s look at the things that should be taken into consideration once you have settled on a type of machine, and let’s assume you have selected a hammer mill.

Most manufacturers will perform test grinding on your material at no cost to you. This is critical in the selection criteria. By running thorough testing you can feel much more confident in your decision. The equipment manufacturer will have the ability to dial in the set up of the machine during testing so as to minimize the need for field tweaking once installed. Try to witness the testing to gain insights as to how the machine will act on your material.

The personnel at most companies will be experienced in processing many materials. Initially the lab technician will likely review notes of prior tests on similar materials to obtain a starting point based on what was successful in the past. If no prior testing were done on this type of material then the technician will rely on his instincts as to what is the best starting point.

An initial test will determine the grinding characteristics of the product. Usually the customer has a target particle size he is looking to achieve. The technician will compare the particle size achieved in the first run against the target and then make the necessary adjustments before the next test. Adjustments continue until the best results are achieved.

There are dozens of variables available when choosing the best possible configuration for your machinery. Changing the screen openings will give you the greatest control over particle size. RPM is also critical as faster blows will produce a finer material, and slower speeds result in coarser material. To a lesser degree hammer size, quantity, and configuration play a role, as do ribbed versus smooth liner plates. Experienced technicians will apply their knowledge to design a machine configuration that guarantees performance.

Once equipment is selected it is usually advisable to take advantage of the engineering services that the company provides. Most experienced manufacturers have worked for years with many different types of machinery surrounding their particular piece of equipment. They will know what works well together, and which doesn’t work so efficiently.

Engineering expertise from the size reduction company can help with the final decisions that must be made such as how the machine is fed and how product is collected from it. Choices such as gravity or pneumatic discharge, types of feeding equipment (auger or belt conveyors, rotary valve, etc.), and whether or not to incorporate peripheral equipment such as dust collection, screening, or packaging equipment must be made. These decisions may seem daunting, but by taking advantage of the technical expertise of a seasoned size reduction company you will streamline the process.

By going through this process you will not only have selected a size reduction machine proven to work on your product but you will also have learned how to properly integrate this equipment with other machinery to make the entire process system function at the highest level.

Thomas E. Warne is president, CEO, and co-owner of Schutte-Buffalo Hammermill LLC (Buffalo, NY), which manufactures a wide range of size reduction equipment.