Dealing with corrosive environments when processing shellfish

Frequent drive replacements used to be the order of the day at Krijn Verwijs, one of Europe’s foremost suppliers of shellfish products and blue mussels.

Live mussels are put into basins with a constant flow of clean salt water and then conveyed wet along the processing lines. This aggressive, humid, salty environment means that all unprotected metal parts along the processing line swiftly corrode. Brand new, conventional cast iron geared motors start showing rusty spots within weeks and need to be replaced within a year or two. Special coatings or varnishes only partly offset the damage caused by the harsh environment.

Stainless steel motors are a very expensive alternative and are also impractical as they need cool-off time before every hosedown.

A solution to this dilemma was provided by NORD DRIVESYSTEMS’ nsd tupH surface treatment technology. This technology enables aluminium geared motors — which can very comfortably be washed down — to achieve stainless steel-grade resistance to corrosion.

While the price of the aluminium drives is higher than that for conventional cast iron units, studies have shown that they will typically last the better part of 10 years in these harsh environments. When weighing up the total cost of ownership and the increased uptime combined with the reduction in health and safety hazards due to paint chipping that occur on conventional units, the decision was easy.

The nsd tupH provides physically ingrained protection. There is no application of a coating but rather a surface conversion that produces a base layer permanently bonded to the substrate. Based on an electrolytic process, this treatment renders aluminium cases similarly unsusceptible to corrosion as stainless steel. The scratch-resistant surface also becomes more than six times as hard as untreated alloy and a thousand times as hard as paint.

It offers a smart alternative to stainless steel. Lightweight, compact and self-draining, the nsd tupH system provides a cost-effective and safe solution for the food industry.

The units are able to handle harsh washdown chemical and cleaning agents including acids and alkaline solutions as well as high-pressure cleaners.

The nsd tupH surface treatments are universally available for all NORD aluminium products.