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Products and solutions, 2006-12-01, 03:01 PM

Professional tank inspection

Whether a one-million liter gasoline-tank or a five-cubic meter-tank filled with wood glue: Munich is the home of a team of longstanding service providers skilled in opening, cleaning or even coating almost all kinds of tanks and tank vehicles. This sometimes highly explosive work is termed tank inspection and calls for wide-ranging skills in expertly handling most every type of stored liquid.

Refineries, chemical and petrochemical operations store their intermediate and final products in tanks of varying size and shape. But whether big or small, all these vessels have to be opened, cleaned and inspected for damage at regular intervals. This is a classical assignment for Harald Krüger and his crew. They transport their special tools to the site, seal off the danger zone, and prepare the tank for entry.

If it is a smallish tank, a hazardous goods container is sufficient; for larger applications, the specialists resort to more expensive suction vehicles for tank drainage. Following the careful opening of the tank, first, residuals of the tank content and the sludge accumulating in the base of the tank are drawn into separate chambers. In this way, the fluid can flow back into the cleaned tank later. The next stage is to degas the tank. The explosive, gaseous atmosphere is extracted until the instrument indicates the targeted values.

Only now do the men enter the tank, with or without respiratory masks, depending on the stored media. This is followed by scraping, suction-extraction and in some cases even sandblasting or water-jet cleaning work until the inside of the tank is clean. This sounds quite simple, but calls for an enormous know-how in terms of environmental protection and work safety. There are wide-ranging legal, workers' compensation insurance and inhouse prescriptions and regulations for such work which have to be strictly adhered to.

High risk

Harald Krüger is a licensed specialist in such jobs, as he went to school "for ages" on the subject of substances representing a hazard to the groundwater. Xervon's special team including all its equipment is annually re-inspected and re-certified by TÜV, the regulatory inspection authority The requirements are extremely rigid, after all, the men are working day-in, day-out with extremely dangerous substances.

But the professional handling of environmentally hazardous and partly highly explosive stored media is only one prerequisite. Another is the right choice of equipment in order not to endanger one's own life and that of others. "We cannot afford any mistakes; this could be fatal for us. Just one spark and such a tank blows into pieces," is how Krüger describes the risk. The jobs are performed, for instance, with tools made from beryllium, a very hard light metal which does not create any sparks when working on the steel tanks.

Hot corrosion protection

When the tank inspection staff hand over the tank to the customer for entry, it is so clean that possible damage on the ground or at the fixtures is visible and repairable. "And should the tank receive a subsequent interior coating or an existing coating needs to be repaired, we can do this as well," tells us tank inspector Krüger proudly. "We are among the companies officially licensed for tank inspection and, at the same time, certified to carry out a special hot spraying process for interior tank coating with epoxy resin." Proof of the coating team's professionalism: only four German companies have been selected and approved to carry out interior tank coatings for NATO, and Xervon is among the privileged few.

The industrial services provider not only has official certification, it also possesses the EUR50,000 equipment needed for the corrosion protection process developed back in the seventies. However and to Krüger's regret, this is rarely needed. "The coating is simply too good," he grins. "Only recently we opened up a tank that had been coated at the end of 1970, and its coating was still impeccable."

Pioneer for bioreactors

With its special hot-spraying process ThyssenKrupp Xervon is also leading the way in the coating of bioreactors. "We coat these gigantic soup tureens with surfaces of 3,000 and 4,000 m². Or we do some touch-up work in the case of the older reactors whose interior coating may have been eroded in part by these extremely aggressive chemicals," is how Krüger describes another specialty of his crew.

But back to conventional tank inspection. Whether recoated or not, once the owner has accepted the cleaned tank and given his o.k., the Xervon specialists recheck it for tightness and the proper working of the connections, and then move on to the next job. For the next few years, the steel colossus stays sealed.

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