Keeping it clean

The meat products scandal that has rocked the UK food manufacturing industry is likely to heighten the focus on all aspects of safety at food processing plants. This includes the compressed air and pneumatic equipment and related automation and robotics, which are now integral to many operations.

Compressed air and pneumatic products are governed by very strict rules designed to minimise the risk of contamination. But even with equipment that is properly designed, operators and technicians still have to closely monitor their systems to ensure production remains free of any risk of contamination.

Many end users of oil-free compressors, for instance, are unaware of the amount of oil vapour that can be sucked in by a compressor in an industrial location.

“Measurement readings of the levels involved often shock end users,” according to BEKO Technologies, though it adds that problems can usually be readily fixed by installing a carbon tower or equivalent oil-removing system.

“The consequences of oil contamination for these industries’ end products is unthinkable yet very few companies today are measuring the vapour carry over,” comments BEKO.

At Maintec 2013, BEKO, highlighted its Metpoint OCV, which uses a photoionisation detection system to measure the oil in compressed air. The unit is said to detect oil vapour down to 0.003 ppm, or in terms of the ISO standard better than class 1 to ISO 8573.

According to BEKO, Metpoint devices are working well in several blue chip companies making mineral water, pharmaceutical products and laboratory testing.

Unlike conventional oil-free compressor technologies, the DH range of water-injected screw compressors from CompAir does not contain a single drop of oil. This, claims the company, provides the complete air purity required by the most stringent quality standards.

The recently upgraded unit has been certified ISO8573-1 CLASS 0 (2010) and silicone-free as standard, making it suitable for operators in the, chemical, pharmaceutical and food & beverage industries.

Air purity is achieved through an oil-free design, where high-quality water injection lubricates, cools and seals the compression process, providing low operating temperatures of just 60°C resulting in high efficiency and low component wear.

Meanwhile, equipment makers are governed by strict regulations, such as EN1672: Food Processing Machinery General Design Guidelines, which stipulates clear requirements for food areas – where the surface is in contact with the main product flow; splash areas – where food may splash but will not be reincorporated into the product; and non-food or ‘product-free’ areas.

In food areas, pneumatic components should be engineered from corrosion-resistant, non-toxic and non-absorbent materials and should be suitable for washdown processes, according to Frank Schnur, technical director, food & beverage at Norgren.

This, he said, might typically mean specifying stainless steel cylinders, valves and fittings along with food grade tubing, to minimise contamination risks.

The design and construction of the shape and surface finish should prevent liquid from being retained, Schnur also advises.

“Systems and components should either be open for easy cleaning, or completely closed and sealed to eliminate the risk of contamination,” he adds.

For splash areas, the designs should be similar to that in the food area, the Norgren expert continued. Requirements on materials, here, are less stringent – as long as there is no risk to, or adverse effects on the food product being handled.

However, materials must still be easy to clean and capable of being disinfected, where required.

Schnur said anodised or coated aluminium cylinders, plastics valves and tubing can all feature in the design  of these components, as long as the requirements are clear and materials are acceptable in the application.

Even in non-food areas, the quality of design must not be compromised, said the Norgren expert noting that materials which are both easy to clean and resistant to corrosion need to be specified.

Pneumatic cylinders can typically be either anodised  or coated aluminium, while ISO valves, plastics fittings, control cabinets, FRL (filter-regulators-lubricators) units and polyamide tubing can also be used, he added.