The lifespan of the Flowrox pinch valve is significantly longer than Michigan Sugar’s original valve.

Michigan Sugar in Bay City, Mich., runs 24/7 from August to April. The sugar season is brisk, and manufacturing occurs in three shifts with continuous operation. Holidays are ignored while the factory keeps chugging, processing the sweet stuff for stockings and Easter baskets.

A sticky situation

This well-oiled, meticulous system was getting jammed up by a simple cast-iron butterfly valve with an EPDM sleeve. The valve helps regulate the two-inch “milk of lime” line, which carries a mixture of sugar juice and lime. The milk of lime is a gritty texture, like sandpaper, that was eating away at the liner of the butterfly valve when it was partially open. With the butterfly valve, the stainless steel disc and stem, as well as the rubber liner or seat, came into contact with the media, and its corrosive nature was exacerbated by the 160-degree heat of the line. Production was getting held up every two weeks, sometimes even once a day.

“The milk of lime process does run continually. It is critical to the operation as this mixture helps to purify their system,” explains Dave Eischer, Outside Sales Representative for The Macomb Group’s Midland Division.

A better solution

After evaluating the conditions and purpose of the line and the valve, Dave recommended a Flowrox pinch valve. The Flowrox pinch valve has a rubber sleeve with several material options, and the valve’s design ensured the media wouldn’t touch the working parts.

Taking the specs back to the factory, engineers decided on a SBR/T (styrene butadiene rubber) sleeve that is resistant to abrasion. The pinch valve package also has an automated pneumatic actuator with positioner and feedback module, allowing Michigan Sugar to control how much media flows downstream.

A resounding success, the new valve lifespan was increased from days to three months.

“Michigan Sugar was ecstatic,” Dave reports. “Not only did it save many labor hours changing out valves, but it also saved downtime for the plant.”

Additional improvements

But Dave wasn’t completely satisfied with the three-month lifespan, so he kept his mind on the problem. He finally decided that reducing the port sleeve from 2 inches to 1 1/4 inches would increase the lifespan to cover a full nine-month sugar season.

“We wanted to get a full campaign out of this sleeve,” Dave explains. “I thought about it for a while and thought maybe if we used a reduced port sleeve, that it might help. This valve was used for control. The pinch bars did not have to stretch the liner as much when controlled and the liner was thicker in the reduced area allowing for more wear.”

Dave’s persistence paid off. “This sleeve yielded a full campaign of trouble-free use,” he reports.

It wasn’t long before word of this great solution spread elsewhere.

“As this was a success, I introduced this same valve package to their other plant in Sebewaing, which has the same milk of lime process,” Dave says. “Michigan Sugar’s Sebewaing plant had the same lasting results, saved labor costs, and reduced down time. Both plants have since purchased valves to be used as a bypass so if the main milk of lime line gets plugged, they can continue to operate.”

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