Ice-cold cost cutting

Photo | GB Glace
Marginal Column

July 2011

 

GB Glace, an ice cream manufacturer in Sweden, has slashed costs and boosted process quality with a decentralized pneumatic concept.

 
 

Making ice cream would seem to be a recession-proof business – since that treat is both a tasty pleasure in the summer and a source of comfort on dreary days. In addition to many icy secrets about quantities, ingredients, and mixing proportions, the technology is a major part of the recipe for success at GB Glace. By changing over to Rexroth pneumatic valves from the Clean Line series CL03, with integrated PROFIBUS communications, the company was able not only to optimize hygiene and costs, but the quality of the process, as well. GB Glace, with its three hundred employees in Flen, Sweden, is a member of the Unilever Group and is one of its ten European ice cream production sites.

About forty-five million liters of ice cream are made here each year. Of that, about seventy percent stays in Scandinavia and thirty percent is exported to all points of the world. Huge silos and tanks, automatic pasteurization and blending arrays, powder pumping machines, and precision scales shape operations at this ice cream producer. And in spite of these huge dimensions, it is the small technical details above all that make a major contribution to success at GB Glace.

Innovation instead of replacing parts

The best example is the conversion from conventional pneumatic systems to modern valve technology with bus-based communication. “Our previous system had done a fine job ever since it was installed in 1989. But at some point we discovered that spares were no longer available on the market,” says Karleric Idegren, process project engineer at GB Glace in Flen. “So first we looked for replacements for the components. And all the thinking we invested in the problem ultimately gave rise to a new pneumatic actuation concept. Rexroth presented a design and that is what we are now using with great success.”

At the center of the new system are the Rexroth CL03 series valve manifolds. The Clean Line (CL) name says it all. The valves are distinguished by their hygiene concept – certified as per the European Hygienic Engineering and Design Group (EHEDG) standards, achieving the superior IP69K safety class, and with the bus connection integrated into the valve manifold system. The CL03 can be mounted right at the line and requires no external switchgear cabinet. “Instead of simply replacing the components – at great cost – we have now invested in a technologically mature and cost-favorable solution,” says Idegren.

The engineering details are more than convincing. The CL03 is easy to clean and maintain. It is made up of individual base plates with internal wiring and can be populated with up to sixteen valves. The individual valves in turn can be set for two different pressure levels. This is necessary to drive the cylinders in a unit at differing pressures, corresponding to the power needed. The sixteen valves in the system can thus drive sixteen different cylinders and offer the ideal pressure level for each unit served.

Cutting costs – Boosting efficiency

Thanks to the decentralized configuration of the pneumatic system – all the valves are close to the using units, such as cylinders, skid drives and grippers – both the valve cabinets and any additional PROFIBUS cabinets can be done away with at GB Glace. This means that assembly effort is reduced significantly. “And now we’ve also started converting the pneumatic system at the tanks in the blending stores. There, once the system is finished, about 330 functions will be available for the process valves.

Fourteen switchgear cabinets, and the wiring, will be eliminated in this one area alone,” the project engineer emphasizes. “What’s more, we save four hundred meters of pneumatic lines and three ramps to compensate for height differences, so that a full twenty-five percent of the cost reductions are due to eliminating components – and their installation, of course.” A further detail for success: Faster response by the valves. While the earlier piloted valves took ten seconds to fully open or close, today’s solenoid valves take just three seconds. If the prescribed time period is exceeded, then an alarm is generated so operators can respond more quickly. Idegren: “That increases safety, reliability and profitability since a defective component in the final manufacturing phase, for example, can cause up to five thousand liters of finished ice cream mix to be spoiled.”

All these facts show how much effort and how much money users can save by selecting a high-intelligence concept. “And here we haven’t even taken a look at the improvements we attained in the process itself.” This brings Idegren around to another advantage: increased efficiency. Less pneumatic piping means less dead space, lower pressure losses, and thus reduced air consumption. “The new system achieves functional improvements and is simpler in its design. The system works even more efficiently and reliably than ever before. What’s more, reduced installation work and especially the lower investment costs shorten the amortization period,” Idegren sums up.