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FOOD INDUSTRY FOCUS APPETITE FOR IMPROVEMENT The food and soft drinks industry is the UK’s largest manufacturing sector and has remained strong in the difficult economic conditions that prevail, even as commodity prices have climbed. One reason for this is that, whatever the economic climate, we tend to carry on eating and drinking product of one kind or another. However, it may also have something to do with good installation and maintenance. Food processing and packaging companies understand more than most the vital need to protect production and optimise productivity, and ensure reliable predictive and preventative machine maintenance programmes to avoid delayed deliveries, wasted produce and damaged reputations. In food manufacture and processing, components must perform consistently well under both extreme temperatures and high levels of humidity. Crucially, they must also meet strict hygiene requirements and retain their integrity during often vigorous cleaning processes. An extensive range of bearings and seals has been developed with specialised features that meet these needs, enabling food and beverage manufacturers to maintain and increase efficiency. Manufacturers can also reduce unscheduled downtime by introducing a more controlled, predictive maintenance approach. For example SKF recently assisted a dairy product manufacturer that was experiencing a particularly high incidence of unscheduled maintenance and downtime. This project began with vibration analysis on a number of assets, which identified bearing and pulley drive problems and misalignments that could have developed into serious incidents and yet more damaging stretches of downtime. By first identifying and later replacing drive and bearing components, the plant enjoyed increased confidence in the reliable operation of its blowers, fans, pumps and gearboxes. However, even without an asset optimisation programme food and beverage manufacturers can achieve performance and efficiency gains by, for example, looking at the drive chain. With drives expected to work reliably day upon day (and in some applications around the clock), the best manufacturers are preparing their belts and chains for high performance in extreme temperatures and/ or contaminated environments. Corrosion Resistant Chains in stainless steel or with a protective coating cope with not only aggressive environments where protection is required to withstand the elements but also hygienic applications such as food processing where the surrounding environment needs to be protected from contamination. Heat is a challenge common to food manufacture and processing applications, with bearings and seals continually subjected to extreme temperatures, exceeding 150ºC in baking, frying and roasting equipment. SKF Y-bearing units have been developed to withstand an extremely wide range of operating temperatures between -150ºC and +350ºC and require little or no lubrication, enabling users to reduce both maintenance requirements and costs. Where temperatures do not exceed 95ºC, Solid Oil bearings, which feature a solid form of lubricant that completely fills the free space within the bearing, minimise the risk of food contamination, as the components are able to withstand considerable centrifugal forces without leaking. At the opposite end of the temperature scale, components are also under considerable stress. Standard seals are generally unable to cope with temperatures inside freezers, leading to equipment failure and downtime, while lubricants can also freeze, bringing production to a standstill. Seals are also damaged by severe changes in temperature, such as when low temperature equipment is cleaned during wash-downs; temperature can change dramatically, causing the air in a bearing first to expand as it heats up and then to contract as the temperature drops again, putting immense pressure on the seal to open up. These intense cleaning processes also present the risk of moisture entering a bearing cavity and corroding the component. However, a range of seal materials have been developed for use in food industry applications, to prevent the bearings being corroded and food being contaminated by leaking lubricant. For example, PTFE is able to withstand extreme temperatures and lubricant-free installations, as it displays low friction levels and will not adhere to a bearing’s counter surface. These seals can also effectively withstand particularly aggressive chemical cleaning, eliminating the problem of flaking and bacteria accumulation. PTFE seals are available in FDA approved compounds, specially designed for reducing contamination in food processing applications. Take an example… The result of applying these innovations to the food and beverage industry is frequently a massive payback on investment when measured against the cost of maintenance and downtime that would otherwise be incurred. For example Evron Foods who specialises in the manufacture of bakery products for retail, wholesale and beyond, both on behalf of private labels and under its own Easibake brand. The company operates from two sites, one based in Northern Ireland and the other in Wales. At both of these sites, transfer units move trays of product through the ovens to carry out the baking process. These transfer units run on Achieving maximum profitability in the food and beverage industry relies heavily on the ability to maintain and further increase manufacturing efficiency and product quality. Phil Burge, Country Communication Manager at SKF, explains how food processing and packaging companies can make significant improvements to production line efficiency. rollers inside the ovens and four rollers are required for each support station along the way. As there are five support stations in each oven, and therefore 20 rollers, each oven requires 40 bearings. The efficient daily repetition of this process therefore depends greatly on the use of efficient, resilient bearings but Evron were growing increasingly unhappy with the existing bearings that were simply unable to cope with the high temperatures of the ovens and required replacement at a rate of approximately once every three months, causing frequent downtime and lost production. The solution was to use high temperature bearings, which are fitted with a graphite cage that releases minute amounts of graphite powder to lubricate the bearing, offering an excellent dry lubricant option for low-speed, high temperature applications such as ovens. The switch effected a 1000% improvement on the previous bearings and have extended maintenance intervals from three months to almost three years. SKF (U.K.) Ltd, Luton, Bedfordshire Can be contacted on: Tel: 01582 490049 Fax: 01582 848091 E-mail: marketing.uk@skf.com Web: skf.co.uk Process Industry Inforem r October-November 2013 43


PII Oct-Nov 2013
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