At the Hormel Foods Corp. plant in Fremont, NE, the primary cause of bearing failure on the production line was corrosion caused by the high volume of water and cleaning solutions. The 600,000-sq.-ft. pork-processing facility produces well-known foods such as SPAM luncheon meat and other Hormel meat products.
Food-processing companies such as Hormel operate under stringent USDA sanitation regulations that demand the highest levels of hygiene and bacteria control. This environment requires constant inspection and cleaning of not only the conveyors and other food contact areas, but also all processing equipment and surrounding walls and floors. Maintaining these standards means cleaning procedures that can wreak havoc with the equipment components, especially critical housed and mounted bearing units. Consequently, maintenance people are constantly inspecting equipment and shutting down operations to replace corroded and stained bearings, a procedure that costs production time and money.
Until recently, Hormel used various brands of bearings, most often nickel-plated units with non-corrosion-resistant ball-bearing inserts. In six months or less, seals failed and allowed water and contamination to enter the bearing. This intrusion would cause the raceway to wear and eventually fuse the bearings, which would lock the unit to the shaft. Frequently, failures were catastrophic, requiring complete shaft replacement.
Charles Brown, manager of plant engineering at Hormel Foods, says he found a solution in Kilian Survivor PS bearings produced by The Torrington Co., Torrington, CT. The housed units combine corrosion-proof components for extended life and reduced maintenance in the demanding industrial applications typically found in the food industry. The polymer housing and special stainless steel bearing insert resist a wide range of common corrosives and contaminants, including acids, alkalis, solvents, detergents, oils and other chemicals. Specifically designed for moderate loads and speeds in processing and packaging environments, the Survivor PS polymer resists caustic chemical washdowns as well as steam and heat temperatures up to 250 degrees F and brief exposure up to 320 degrees F. The wide-inner-ring design provides shaft support and setscrew locking. All materials, including the lubricant, comply with federal food-processing requirements.
"We need bearings that will withstand some of the toughest applications in our industry," says Brown. "Sterilization is integral to our production process and we are constantly washing the area using high-pressure (250psi) hot water (140 degrees F) and strong cleaning solutions. Before switching to the Survivor PS bearings, we replaced our units every six months. Now, most of our bearings are still running after two years in the same corrosive environment. This is more than four times the operation life of other bearings we've used."
Hormel uses Survivor PS pillow blocks and flanges on five conveyors that move food cans through the washing process prior to adding the product. The housed units support head and tail shafts that hold the conveying chain. The company will have 20 to 25 bearings running at any one time. These include 2-bolt, 4-bolt, and pillow-block configurations. Shaft size ranges primarily between 3/4 in. and 11/4 in., determined by location.
Brown estimates the return on investment for the Survivor PS units is one year. The units are more expensive than competing products, but pay for themselves in the first year. For every six months of operation after that, each unit represents a $50 to $100 savings for the company, says Brown, who adds that the downtime associated with unit replacement can also cost the company as much as $1000 per hour, depending on which conveying line needs service.
The Torrington Co., 59 Field St., Torrington, CT 06790; 800-854-0175.