Design and construction of polyethylene tanks
for the industry.
Tanks made of polyethylene (PE), by rotational molding, are resistant to atmospheric agents and UV rays as well as to aging and are therefore suitable for burial. These tanks are suitable for the storage of food, drinking water, diesel and all chemical products, even aggressive, compatible with polyethylene.
Rotational molding is a technological process that makes it possible to produce hollow bodies in a single piece without the need for welding. This technology allows to obtain pieces free from internal tensions and with uniform thickness.
Even large-sized articles with very complicated contours can be moulded, even with different surface finishes, all with investment costs in equipment that are much lower than those of other technologies.
Currently, most of the production is carried out with linear and cross-linked polyethylene, followed by polypropylene, polyamide and polycarbonate. The peculiarity of this technology lies in the fact that the mold rotates according to two axes: a primary one with a fixed direction and a secondary one with a variable direction. During all phases (excluding loading and unloading) the mold always rotates, but never rapidly.
Thanks to the two movements, the polymer invests the entire internal surface of the mold which, once heated in the oven, melts the polymer which adheres to it, covering it. In this way, layer after layer, all the polymer is melted, giving rise to the finished piece.
Since the rotation is slow, the polymer does not cover the mold thanks to the centrifugal force generated by the rotation, but only because it is melted when it comes into contact with the walls of the mold itself.