September 2020

COMPRESSED AIR 40 HYDRAULICS & PNEUMATICS September 2020 www.hpmag.co.uk industry. According to Food Drink Europe (the trade organisation representing Europe’s food and drink industry), the food and beverage industry in the European Union alone employs 4.72 million people, generates a turnover of € 1.2 trillion and € 236 billion in value added, and is the largest manufacturing industry in the EU; feeding a population of nearly 450 million. Contaminant-free air ≠ low life cycle cost? F&B operations require compressed air that is completely oil-free. These applications demand wide operating temperatures of 0-45degC, stringent air purity standards higher than ISO 8573- Class I, high levels of safety, and eco- friendly operation to name but a few. And as in many other industries, the demand is for efficient compressors capable of running with minimal maintenance and for longer periods. The inadvertent and unintentional presence of contaminants can enter the food chain at all stages: in packaging materials and transport materials for raw ingredients, the improper use of machine oils or lubricants and in the upstream packaging, process and transport materials. The ALARA principle states that the presence of a contaminant should be reduced to “As low as reasonably On a recent visit to one of the European production sites of a major global drinks manufacturer, I was taken aback to learn of the complexity and seriousness of their approach to ensuring oil-free air. While they had employed the latest technologies and machines, they had not foreseen that small oil leaks would be spilled onto and absorbed into the concrete floor during maintenance. This oil would evaporate during the hot season. And that those contaminants would then be drawn into the compressor, leading to minimal, yet important oil contaminants in the final product. Their solution involved placing the compressor equipment in a contaminant-free environment, regular cleaning of an epoxy-resin floor and strict protocols to maintain this environment. For food and beverage (F&B) companies, the importance of oil-free compressed air is of course, nothing new. Oil-free compressors meeting ISO standard 8573-1 specifying purity classes for particles, water and oil have proven critical. But as with all such stringent standards, they add to costs, energy consumption and ultimately make life harder for operations leaders who need to reduce the life cycle cost (LLC) of their capital investments. And there is more. As a consumer, I’m also acutely aware and proudly part of the consumers’ challenge to all sectors, including food and beverage, to improve the environmental sustainability of their organisations. From farm to fork A well-known phrase, ‘from farm to fork’, is often used in consideration of the sustainability of the entire food production supply chain. Within this reference, there is rightly focus on the need to avoid contaminants ‘from farm to fork’. Given that compressed air is used across most stages of food and drink production, from oxygenating the water in aquaculture or fish farms, preparing fizzy drinks or in the sanitation of bottles and packaging to name a few, contaminant- free air is a must. And it is a must in a very important Achieving contaminant-free compressed air in food and beverage operations achievable”, clearly establishing the priority for all aspects of food production – especially the compressed air industry. Addressing this issue, in 2018, Food Drink Europe published the ‘Toolbox for Preventing the Transfer of Undesired Mineral Oil Hydrocarbons into Food’ by the Germany Food Federation (formerly known as German Federation for Food Law and Food Science (Bund für Lebensmittelrecht und Lebensmittelkunde - BLL). This toolbox contains guidance and recommendations for the food industry in limiting contamination from various stages of food production. In relation to compressed air, this guide recommends to “check compressed air for oil penetration on a regular basis” and “use oil-free compressors, and if possible, draw in zero-emission environmental air”. It sounds simple, but real-life food and beverage operations are anything but simple. Filter it out To meet such standards, in an oil-free screw compressor, an air cooler removes the heat from the compression chamber. The dry running rotors rotate at high speeds to get volumetric efficiencies injected. Timing gears synchronize rotation to ensure no contact. A separate lubrication system lubricates the timing gears. And finally, an effective sealing system prevents the entry of lubricating oil into the compression chamber. Filtering removes much of the oil but not all of it. For example, pre-filters, high efficiency coalescing filters and activated carbon filters remove trapped oil to a great extent. But these filters themselves have characteristic limitations. For instance, above 20degC, coalescing filters do not remove fine oil vapours, leaving very fine particles of residual oil in the form of aerosols; and activated carbon filters are not usable at filtration temperatures above 40degC because the carbon then absorbs the oil vapour, gets saturated, and becomes ineffective. Furthermore, to ensure no residual oil, air-borne particulates or vapour could David De Pril, head of product management and marketing, ELGi Europe, considers how to achieve a competitive advantage via operational efficiency in an industry faced with strict food safety regulations and productivity pressure. David De Pril: Continual innovation.