A pneumatic conveying system is used to transport bulk goods by means of air or gas. There are different designs of the feed pipes to transport a specific product gently and thus minimise the risk of abrasion and wear and tear. The composition and quality of the inner surface of the pipes used play a crucial part here.
Upon contact with a smooth pipe wall, friction pressure and the resulting increased temperature can lead to a partial plasticisation of the plastic granules, a film and then threads are formed (so-called "angel hair" or "sauerkraut"). This may result in material loss and contamination right through to complete blockage of the pipes.
A special treatment of the inner surfaces of pipes restricts the formation of threads: depending on the physical properties of the material to be transported and the type of transport, individual degrees of roughness on the inner surfaces of the pipe system can be ordered. In this specific case, the optimal solution is the raumatic-surface. Rollers create a structure in the inner surface that significantly reduces friction.
For the current project, about 1,300 metres of pipes in the size range from DN 150 (168.3 mm) to DN 250 (273.0 mm) with wall thicknesses of 3.0 mm are being produced. The scope of delivery also includes various elbows with slim radiuses from 850 to 1 350 mm. The inner surfaces of both the pipes and the elbows are produced in a raumatic-design.
Bernd Eggelmann, product specialist for conveyor technology in Sales Spools and plant construction, explains: "BUTTING is able to offer the optimal solution depending on the bulk material transported, in order to avoid material losses and unnecessary maintenance. This creates a high level of customer benefit. In addition, the use of elbows with slim radiuses guarantees gentle redirection of the material conveyed. The large radius of the elbows reduces the effect of a collision and thus prevents damage to the material conveyed and the pipe wall."
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