TECH FLASH
Electropolishing cuts cleaning time in removing stubborn deposits
New report shows surfaces produced by electropolishing can cut costs and increase food safety.
Regular cleaning of production equipment is often a time consuming part of the food business, but case studies are showing the smooth surfaces produced by electropolishing can reduce the cleaning time of stainless steel.
A recent report by Keith Raney of UltraClean Electropolish Inc. and Richard Avery, consultant to the Nickel Institute Inc., details the ability of an electropolished surface to reduce cleaning time to remove stubborn deposits not removed by usual clean-in-place methods.
Electropolishing removes a layer of metal, including the rough profile of peaks and valleys that are a result of mechanical finishing operations.
Raney and Avery say most plant operators do not consider the impact removing stubborn deposits can have on operations.
They cite one example of a food plant that marinated chicken using hot air to blast the chickens as they moved on a conveyer belt through an oven. In this process, marinade was blown off the chicken and onto the air ducts, forming hard deposits over time that could not be removed through conventional processes.
The oven parts needed to be manually cleaned for eight hours with cleaning solutions. On a trial basis, some of the parts were electropolished and compared with non-polished pieces. The reduction in time needed to clean the electropolished pieces resulted in the company polishing all the components for a complete oven.
Because of the reduction in the cost of the cleaning chemicals typically used on the equipment, the company was able to recoup its electropolishing costs in less than 90 days.
Electropolishing is traditionally completed by dipping a steel piece into a tank filled with a special acid electrolyte. Acting as a conductor, the piece is connected to the positive side of a DC power supply.
The negative side of the power supply circuit, the cathode, is usually a copper piece, but it can be any metallic material (stainless steel, titanium, lead) that will conduct electricity and hold up to the electrolyte.
Two other electrical conductors, typically copper, are connected to the negative side of the power supply and inserted into the tank on either side of the work piece. As a current passes through, metal on the surface of the work piece oxidizes and dissolves into the electrolyte while a reduction reaction takes place on the negative conductors.
Through this process, stainless steel parts are polished, cleaned and freed of tough deposits and provided with a smooth surface that is easier to sterilize.
Though often done in a tank, manual electropolishing with a hand-held tool is also possible, allowing a variety of piece sizes to be polished in place in field installations.
Considering the options, Raney and Avery say electropolishing is a technology food processing plants should consider adopting not only for cost reductions, but for food safety as well.
For more information:
Keith Raney, UltraClean Electropolish Inc., 281 384 7773, rkraney@ultracleanep.com
Richard Avery, Nickel Institute Inc., 207 874 0623, richardea@aol.com
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