Control Solution Boosts Flour Production, Safety
EP Editorial Staff | October 22, 2018
Advanced automation system significantly improves mill uptime, output, and reputation.
From cookies and cakes to pretzels and pastries, many of the snack foods enjoyed by consumers along the Eastern Seaboard contain flour milled in the tiny town of Mount Joy, PA. Here, Wilkins Rogers Mills (wrmills.com) transforms soft wheat into the key ingredient used by commercial bakers to satisfy America’s sweet and salty cravings.
The Mount Joy operation is one of three plants operated by Wilkins Rogers (WR), whose history dates to 1913, when Howard Wilkins and Samuel Rogers purchased a flour mill in Washington, D.C. Aside from the fundamental process of grinding grain and sifting out particles to form a pure powder, today’s industrial flour mills bear little resemblance to their ancestors. Automated processes have transformed the old back-breaking, hand-blistering manual labor required for centuries to extract flour from wheat.
The site encompasses two milling units, along with extensive equipment for grain transfer, flour handling, packaging, and bulk shipping. Each milling unit employs massive rollers that separate the wheat’s hard outer coating from the flour-producing endosperm. Then comes the process of sieving, sifting, and regrinding the flour into different grades, depending on the needs of the bakers that buy it.
The Mount Joy plant can produce as many as 700,000 lb. of flour daily. Meeting that target, though, was becoming increasingly challenging in light of the operation’s outdated control system, which included a vintage-1990s programmable logic controller (PLC). To make changes to the program, operators had to use a laptop computer running Windows 95. Spare parts and support were nearly non-existent, and the parts that were available were either used or remanufactured with no warranties.
Locating replacement parts created even more problems. Operators were constantly searching for parts to keep on hand in case of a shutdown. The reliability of those spares, however, was spotty at best.
The plant’s single human-machine interface (HMI) was also very basic in what was provided for operators. “The computer screen was very old and didn’t give us a good visual representation of the process,” explained Aaron Black, director of operations. “Bigger picture, we had difficulty monitoring our plant’s performance and measuring output accurately.”
According to Black, the person who installed the control system in the ‘90s had difficulty supporting it anymore because of the age of the technology. The question for senior management wasn’t if they needed to invest in new control technology. The question was when. That answer arrived in mid-2015.
GAINS IN EFFICIENCY, SAFETY
Black and his operations team turned to Kice Automation, part of Kice Industries, Wichita, KS (kice.com), for assistance. Well known for its expertise in the flour-milling business, Kice had consulted with Wilkins Rogers on several smaller projects.
“No one checked off all the boxes like Kice did,” Black said. “We were well aware of their advanced knowledge and attention to detail.”
Kice’s advanced knowledge in milling processes, including its experience as a solution partner within the Rockwell
Automation PartnerNetwork program, helped convince Black and his team that instead of a mere replacement, they should implement an entirely new control infrastructure for the Mount Joy facility.
“The Mount Joy team had a wish list of capabilities that couldn’t be realized with just a PLC upgrade,” said Syed Ashraf, vice president of automation/electrical at Kice.
Deploying new sensors for added worker safety was near the top of that wish list. “We care about employee safety first and foremost,” Black stated. “With new sensors on equipment tied into the control system, we not only enhanced the safety but reduced the chances of equipment failure.”
The Kice team also helped Black meet another key goal: systematically replacing the obsolete control system with little or no downtime in production. That changeover feat required more than six months of careful planning and collaboration between plant personnel and Kice engineers.
“When we were ready to switch out the PLC, we were fortunate that our existing motor-control centers had hand-off-auto capabilities,” Black said. “That meant we could run all the equipment manually, allowing time for final wiring in the new panels.”
The centerpiece of the state-of-the-art infrastructure is the Logix Control Platform with a distributed I/O architecture. The Rockwell Automation solution also included redundant HMI servers, allowing production back-up and spare capacity for future applications.
Four new workstations were strategically installed in the facility, allowing operators to monitor real-time production data using the FactoryTalk View Site Edition (SE), supervisory-level HMI software from Rockwell Automation.
“For the first time, information on wheat extraction, flour yields, and peak-production amounts all feeds into a highly visual display, allowing operators to accurately optimize the process,” Black explained. “And if we’re not meeting our targets on a daily or trending basis, we can track what’s happening to find out why. Our new insights also are invaluable for the maintenance folks.”
Multiple workstations and equipment sensors have contributed to uptime and worker safety.
As Black pointed out, alarms can pause or even suspend the milling process. “Now,” he said, ”if a sensor sets off an alarm, an operator can simply go to the nearest workstation, acknowledge it, and take care of it. No more running around to try to figure out the problem.”
The remote support provided by Kice is another boon to Black’s peace of mind. “An engineer in Wichita can jump on our system in a minute, see what’s happening, and help us through a solution,” he noted. “Kice deserves a lot of credit for the work they put in and their continued support to make this a successful project.”
NEW SYSTEM CAPABILITIES
Proof of the new system’s success is quite evident, including decreased downtime, according to Black. “With the Rockwell Automation solution,” he said, “we are maintaining our good yields and meeting our production targets, both things we can more accurately measure now.”
With the Mount Joy mill’s new infrastructure in place, Black and his team are consulting with Kice about how to further leverage the system’s advanced capabilities.
“We have the potential to monitor a lot more than just pieces of equipment,” Black said. “I have a list of enhancements that we can bolt on.”
Topping that list is automated energy monitoring. That’s because power usage is the mill’s second-largest operating cost after personnel. Industrial strategies for controlling power costs, especially during peak demand periods, must be reported using accurate energy-use data. “The future holds a lot of promise with our new system,” Black concluded, adding that the Kice-designed solution, built on Rockwell Automation technology, will be “the standard going forward for our sister facilities.” EP