Water conservation initiatives have prompted thousands of bottlers worldwide to convert to dry conveyor lubricants in the past decade, although the human beings in those bottling halls may be the biggest beneficiaries of the change.
Conveyor lubrication is needed to reduce friction between the belt and the bottle and to prevent breakable containers from colliding during conveying. Soapy water is the traditional solution, reducing the coefficient of friction but also creating rivulets of wastewater that become slip-and-fall hazards.
In 1975, BASF Wyandotte Corp. patented a cocktail of fatty acid soap plus a surfactant and monostearyl phosphate, and fatty amines, phosphate esters and dry emulsions followed. All resulted in slippery floors. Complicating the complexity of finding alternatives is the fact that different belt materials and bottle compositions require different lubricants. When PET bottles are exposed to a solution of phosphate ester, amine salt and nonionic surfactant, for example, stress cracking can occur.
In the mid-2000s, Ecolab USA Inc., St. Paul, Minn., introduced the first of a series of dry conveyor lubricants under the DryExx name. "DryExx was originally created for use with PET bottles and aluminum cans on plastic conveyor chains," Chad Thompson, senior scientist, wrote in an e-mail. Ecolab's lubricants work with conventional lube spray-nozzles.
"Nearly all package types have successfully been filled and conveyed using dry lubricants," he adds, but glass on stainless steel is a particular challenge. For those bottlers, Ecolab developed DryExx GF. "This is of particular interest outside the U.S. for use with returnable glass bottles," Thompson writes -- to say nothing of North American brewers.
About the time DryExx debuted, Diversey introduced Dry Teck, which also was suitable for PET and aluminum but struggled to overcome the glass-on-steel problem. Now a division of Sealed Air Corp., Diversey is the successor organization to BASF Wyandotte.
Unlike soft drink and juice bottlers, breweries rely on belt lubricants to clean and flush away belt grime, explains Mike Lammers, senior beverage & brewing sector specialist at what is now called Sealed Air's Food Care Division, Racine, Wis. "We've been playing with our Dicolube Sustain formulation for about three years to deliver both lubrication and good detergency," he adds.
Few if any line speeds match those of major North American breweries. Several constituencies have to be satisfied with the results of trials before those bottlers will commit to dry lubricants.
"It's a paradigm change for these plants," says Lammers. Besides maintaining line speeds and keeping the belts clean, potential impacts on the product have to be resolved. For example, a residue of silicone-based lube on the outside of a can or bottle could mix with the beer when poured. "A slight residue can cause the head to break and make the beer look flat," he says. "They want nothing to do with that." Lammers describes Sustain as "a modified diamine" containing no silicone.
To maintain detergent action, Sustain for breweries must be diluted with water, but in much lower volumes than conventional systems. Breweries typically consume 6 barrels of water for every barrel of finished product, Lammers says, with much of the waste generated by belt lubrication. By reducing lubrication water 60 percent or more, Sustain might lower the ratio to 3:1.
Sustainable practices, not cost savings, are driving conversion. "Retailers are getting to the point of demanding that food companies have water-saving KPIs in their plants in order to sell through their stores," Lammers says.
Sustainable manufacturing has particular resonance with craft brewers. New Belgium Brewing Co., Fort Collins, Colo., began trials two years ago with Ecolab's dry lubricant. Inductively coupled plasma spectrometry was used to quantify soil deposits on bottles from both dry and conventional soap lubricants. Mold will grow on conveyors and floors from soap foam, and the foam can wreak havoc with labeling machines.
"Water saving was a huge factor in the decision-making process," says New Belgium's Gary Dick, but maintaining line speeds and keeping emulsions off the bottles also were concerns. Ultimately, the brewery replaced its steel belts with plastic conveyors, slashing water consumption to 80,000 gallons from more than 1 million, and cleaning time was cut in half.
Swapping dry lubricants for conventional conveyor lubes requires deft application control. Some back pressure is necessary to push bottles past a labeler, and even a 2-degree incline can cause bottles to slide back if too much lubricant is brushed or sprayed on the belt.
Reduced water consumption and wastewater treatment are driving conversion, but less broken glass and fewer worker injuries are the silver linings of dry lubrication.