Explosion Protection Case Study Can Food Explode? – Explosion Protection for Muesli Bars

Editor: Dominik Stephan

When eating a muesli bar, one doesn’t normally think of explosions – And yet, the f&b industry is full of explosion hazards. Reason enough for foods giant Nestlé to consider an up-to-date explosion prevention solution. The result is both safe and tasty...

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Dust explosions are the potential hazard in the manufacture of muesli bars; and preventing them from occurring will not only save on downtime but also enhance health and safety issues in the manufacturing facility.
Dust explosions are the potential hazard in the manufacture of muesli bars; and preventing them from occurring will not only save on downtime but also enhance health and safety issues in the manufacturing facility.
(Picture: Snehal Pillai)

Rembe is a worldwide safety specialist in explosion protection, process safety and industrial measurement technology. It provides customers with crosssector safety systems for their plants and equipment.

All products are made in Germany and meet the requirements of national and international regulations. Its customers include market leaders in numerous sectors, including the food, wood, chemical and pharmaceutical industries. The Q-Rohr-3 is the only flameless venting system for use in enclosed spaces that meets virtually all international safety standards.

Food Moods – Why Muesli Can Actually Explode

When eating a muesli bar, one doesn’t normally think of explosions. And yet the manufacturing process of a muesli bar does indeed pose such a hazard. Whenever its components—especially oatmeal—are transported, they produce dust as a side effect. All the ingredients are surrounded by oxygen during production. So when there is a source of ignition, such as a mechanical spark, then all the conditions are in place for an explosion.

The route that is taken by a grain of oatmeal in the production of muesli must not be underestimated. It dashes through the pipe system at high speed. Dust allergies pose to be a hindrance as dust can be found almost everywhere in this production process. For safety and hygiene reasons, therefore, the dust is removed in a suction process.

However, vacuuming the dust does not automatically remove all the hazards. All that is needed for an explosion is the right concentration of dust, a source of ignition and oxygen. To keep the impact of such an incident as low as possible, it is important to have an efficient explosion protection system—a generic term which covers a wide range of protective measures. One of them is Rembe’s Q-Rohr, the original flameless venting system.

Like a High–Performance Heat Exchanger

Ultimately what takes place within the Q-Rohr-3 is an energy transfer. The specially developed stainless steel mesh filter removes heat from the flame, thus extinguishing it, reducing the gas volume and containing the dust particles churned up in the explosion.

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At the same time, it minimizes the pressure increase from the explosion and also any noise pollution down to a level that is barely perceptible. It also reduces the impact of an explosion, the Q-Rohr also serves to protect other parts of the plant and the workforce by not permitting burnt or unburnt dust particles to pass through.

Safety and a Competitive Edge – Nestlé is a Step Ahead

The world-famous food company Nestlé goes one step further, focusing not only on the protection of its assets and its workforce, but also on the availability of its facilities. After all, what’s the use of expensive protection systems if they continually obstruct or even disrupt the production process? Managing Director, Rembe Safety+Control, Stefan Penno, puts this question quite provocatively: “Would you stop your car immediately as soon as a warning light in your vehicle indicates a fault in the airbag system? Or would you drive on, hoping that no accident will happen where the airbag might save your life?”

Safety and smooth routines are particularly important at Nestlé’s Twister Project, a new pilot plant in Orbe, Switzerland. The savings in downtime at this prototype stage will eventually be multiplied in the various systems that Nestlé intends to set up on a global scale.

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“This installation is a pilot system for making various cereal products. The products are manufactured in small batches and are then tried and tested by internal and external testers before the routines are rolled out at an entire production facility,” says Development Engineer, Nestlé Twister Project, Norbert Nemes. “We are really pleased with the Rembe Q-Rohr-3. The entire production process remains within the building, and we do not need any overflow to the outside.”

Flexible Systems Are Ideal for F&B Industries

In fact, the planning, installation and eventual operation of the system are indeed very simple. “When the planning was conducted, all that was needed was a simple standard connection flange. The assembly of the Q-Rohr system then proceeds very quickly, using a dozen screws, and then the system is ready for use,” Nemes continues.

Flexibility is of course absolutely paramount, and indeed not just for a pilot system. If a supplier is unable to respond, thousands of Euros are lost every hour unless it is possible to act quickly and flexibly. Rather than saving money, even during the global financial crisis year of 2009, Rembe decided to invest—especially in the manufacturing of semi-finished products.

This continues to benefit Rembe’s customers such as Nestlé, as they can be served promptly and easily. “While others were opting for empty warehouses and staff redundancies, we decided to move ahead full steam, increasing all our stocks. You may well be asking whether that wasn’t a bit daring. But wouldn’t it also be rather daring to abandon your workforce and your business partners?” declares Penno.

In the case of Nestlé, the importance of two vital factors can be seen: availability and stability. To achieve this, the operation of a pilot plant also requires speed. If, for instance, a new mixture is being run for a muesli bar, and a bursting disc accidentally becomes damaged in the Q-Rohr-3 system, then it can be replaced within an hour. Nemes praises the first-class service of Paliwoda. Felix Paliwoda has been a Rembe partner in Switzerland for over 30 years, “We are provided with spare parts on demand and without any red tape,” exclaims Nemes.

Explosion Protection for Muesli Bars

By providing this service and ensuring the availability of facilities, Rembe saves its customers several thousand Euros per day. But the Q-Rohr-3 passive protection system also has further benefits. There is no need to waste valuable space on overflows or valuable time on servicing. Nemes is clearly aware of the benefits of the Q-Rohr and knows how to make the most of them: “All that’s needed is an annual visual inspection, looking at the system from outside. The rest is handled by the Q-Rohr-3 monitoring unit which provides ongoing feedback to the process control system.”

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This, in turn, saves unnecessary downtime, making Nestlé faster than its competitors in the development of new products. The Q-Rohr-3 system incurs no running costs and is therefore far more costeffective than active extinguishing systems. Nemes confirms that the investment did indeed break even within a matter of weeks.

Safe and Attractive

Rembe even added a pleasant design to the facilities in Orbe. At the big storage silo, directly next to the outside wall of the production hall, Rembe painted five explosion relief panels of the type Rembe EDP in special dark gold. As a result, the façade has lost none of its attractiveness, and the entire plant gives a good impression of being professional and of a high quality.

Beware of Imitations

When asked what Rembe is doing to combat industrial espionage, Explosion Protection Specialist, Rembe, Roland Bunse states, “The Q-Rohr patent has expired, so that quite a few product pirates are now feeling encouraged to flood the market with cheap imitations. Also, there are attempts to misuse similar products with a different performance spectrum for the same purpose. “It’s as if,” jokes Bunse, “you tried to fight a forest fire with a fire extinguisher. Obviously, it helps a bit, but you still can’t save the forest!” Such products are a lot cheaper than the Q-Rohr-3, but they’re not really effective.

“The way to ensure efficient explosion protection in the future is not through cheap and simple products, but through analytical problems solutions,” avers Bunse, thus indicating that REMBE will continue to use its experience—almost 40 years by now—to maintain its position on the international market. This is because the company’s solutions involve safety engineering for the benefit of the people.

* First published in PROCESS India