Sealing technology for clean environments

Small doesn’t mean unimportant

On January 28 1986, Space Shuttle Challenger broke apart 73 seconds into its flight, leading to the deaths of its seven crew members. The disaster was ultimately traced to the failure of a simple component – an O-ring seal in the vehicle’s right solid rocket booster. Never was there more graphic – and on this occasion, tragic – proof that small doesn’t mean unimportant.

In fact, today, sealing technology plays a critical role in many industries. And nowhere is this more true than in those sectors which require a clean environment. But designing and manufacturing products which meet the industry’s needs is a tough challenge – such products must not only satisfy the demands of increasingly tough standards and legislation, they must also meet the cost, speed and efficiency demands of the marketplace. It’s no easy task. Yet it can be – and is being – done. In the last year or two alone, some exciting innovations have become available, and others are well above the development horizon.

Take elastomeric seals, for example. Although these are very commonly found in equipment such as pumps, they are also highly susceptible to attack by the aggressive conditions typically found in hygienic environments. The frequent expansion and contraction caused by exposure to water during CIP processes, for instance, can cause the seal to distort and degrade, while the steam and high temperatures of SIP can make the rubber brittle. The results of such effects can cause real problems in a clean environment – a hard, brittle seal will be unable to flex to its mounting, or may partially break up and release particles into the production stream, while a distorted seal may form bacteria traps that could infect the current, or future, process.

Yet solutions are now available for these problems, and the techniques of aseptic engineering are just one of them. This allows a material’s behaviour, such as swelling, to be predicted to high levels of accuracy, thus eliminating the possibility of dead spaces – areas that can collect a build-up of food and act as bacteria traps. It is a powerful approach to improving seal performance. But there are other innovations too, such as Metal-Detectable Seals. These are made of an elastomeric compound which includes a magnetic (but hygienic) material that can easily be detected if it finds its way into the production process. Thus any fragmentation of the seal can be quickly identified and corrected. The potential savings of investing in such a system, compared to the cost of a product recall (it has happened!) are huge.

Another area of real progress is bio-hygienic technology. This essentially, is the use of rubbers that use a specially developed ingredient (based on silver ions) designed to inhibit the growth of micro-organisms (bacteria, fungi or algae), and deter them from contaminating or colonising its surface. The result is a material that is not merely inherently hygienic, but which eliminates the possibility of foul odours, discolouration, the formation of mildew and slime and which reduces surface degradation – a process that can have a significant effect on the component’s operational lifespan. The benefits of such a technology are enormous.

All of which, of course, leads to the obvious question: where are such products available? The answer is that ERIKS is leading the field in all these technologies, and already offers solutions which make use of them. In fact, at our unique, state-of-the-art Materials Technology Centre in Warrington, we even design and test new compounds to address the latest challenges in the manufacturing industry.

But these aren’t the only areas where ERIKS is innovating in sealing technology. Far from it. Another is the area of standards. Although, traditionally the FDA has been the body which has determined hygiene compliance standards, Europe now has a regulatory framework of its own – the EC-1935/2004 – based on the FDA standard. ERIKS is again leading the way – and is possibly unique – in performing extensive tests (‘extraction’ tests) on all 40 of the seal materials it uses to ensure its seals comply with the European standard. As we go to press, tests on some 25 of these materials have been completed and the remainder will be completed within the next few weeks.

For details on this, or any other of our seal technologies, don’t hesitate to contact us.

Bio-hygienics – how it works

The antimicrobial agent forms an integral part of the rubber compound. It is not simply a skin or liner, and therefore the antimicrobial properties always remain active. Furthermore, any abrasion or wear to the surface of the rubber actually increases the exposure of the silver and with it the efficacy of its antimicrobial qualities.

• Provides effective microbial protection
• Available in a wide range of technical rubber compounds
• Can be incorporated as part of a customised compounding facility
• Forms an integral part of the rubber compound, is durable and non-leaching
• Tasteless and odourless
• Non-toxic, non-flammable, non-corrosive