Controlled Size Reduction

Chicago Grinder Builder Explores New Control Options

Modern Process Equipment designs and builds roller-style Granulizers. The Chicago company was founded in 1957 and, at that time, served exclusively the coffee industry.

“We now have customers in 51 countries,” says Brian Thomas, controls engineer at MPE. “Research, development and production engineering responsibilities are shared on a project basis. All of our grinders are designed and built in Chicago. Since 1985, we’ve expanded our product line. Our Granulizers are used in the coffee, food, chemical, mineral and pharmaceutical industries. From a controls standpoint, the first four industries have very similar needs. In the pharmaceutical industry, however, we also work to minimize the complexity of the controls and reduce the available operator adjustments to streamline the FAT/IQ/OQ requirements.”

MPE’s grinders reduce friable materials in size by fracturing them between pairs of precisely corrugated and aligned rollers. “Each Granulizer is custom-tailored to provide the highest possible yield of good product and to reduce unwanted dust, or ‘fines,’” says Thomas. “We’ve increased our global marketing efforts in response to the increasing financial attractiveness of U.S. equipment due to the weak U.S. dollar, and sales to foreign customers now make up about 20% of our business. We are also the world leader in Turkish, or ultrafine, coffee grinding, soluble coffee grinding and several other areas; this helps drive our foreign sales, as well.”

mike Dilley
Master Technician Michael Dilley inspects the corrugations of a grinding roll.
Source: MPE

The increased foreign sales also impact the machine control choices. “We offer either push-button controls or PLC-based systems,” explains Thomas. “PLC control allows us to provide 25 different recipes that control all of the important grinding parameters. However, many of our customers use their grinders for only one or two different products so the recipe control system doesn’t add much value for them. We try to offer our customers the controls package that makes the most sense for how they will use the grinder. We use primarily Allen-Bradley PLCs. The majority of our projects are customer specs, and A-B is often the supplier of choice. With our increasing sales in Europe, we are developing a PLC control system using Siemens.”

Recent completion of a multi-year effort to develop a single PLC program for its Granulizers has Thomas fully caffeinated. “That will handle 90% of our PLC-controlled Granulizers,” he says. “We made extensive use of the visibility control in the PanelView Plus touchscreen to allow us to turn features on and off and options for each project without writing custom code.”

MPE’s safety systems are hardwired Cat. 3, explains Thomas. “We use Pilz safety monitoring modules and A-B 700S-CF safety relays,” he says. “We haven’t used any safety PLCs. Our typical Granulizer only has eight to 10 safety switches that are in close proximity, so there’s really no advantage to more sophisticated safety systems.”

Security issues aside, Thomas also would like to see more remote access to customers’ machines. “I’d love to find a way to get Internet access to our grinders around the world,” he says. “Being able to remotely view all the operating parameters would greatly aid in advising our customers on how to best operate their equipment. I think this is more of a security issue than a technology issue. While all of our customers would like us to be able to access their grinders, the question is: How do they do so without opening their IT systems to unwanted access?”

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