Andritz (Finland)

Abstract Die neu entwickelte Schubzentrifuge ecoOne von Andritz ist für die Produktion von chemischen Grundprodukten, technischen Salzen und Agrochemikalien sowie Kunststoffen geeignet und behält die Verlässlichkeit und die Wascheffizienz der herkömmlichen Schubzentrifugen‐Technologie von Krauss‐Maffei bei, während Energieeffizienz, Flexibilität und Wartungsfreundlichkeit erhöht und dadurch die Betriebskosten und Stillstandszeiten gesenkt werden.

Abstract Thermal spray coatings are widely used in sealed constructions where a specific seal material is sliding on the coating surface in aqueous conditions. Such applications are often highly corrosive and therefore limit the lifetime and increase the wear of the seal and the coating. In this work special test equipment was manufactured to study corrosion and wear performance of the specific test materials used under chlorine containing conditions at low pH-values. In the test procedure, a rotating seal material was pressed with certain pressure against the thermal spray coating material in the test solution and the wear of the seal and the weight loss of the coating material was measured during the test. Coating samples for the tests were prepared using HVAF, HVOF, twin wire arc spray and atmospheric plasma thermal spray techniques. Corrosion resistant stainless steel material EN1.4404 was tested as a reference together with the thermal sprayed coatings. Altogether four different seal materials were tested and the seal material was found to affect the weight loss of the tested base material and also to the coated material during the corrosion wear tests. Pure graphite seals were seen to accelerate the wear rate of both bulk stainless steel material and the thermal spray coatings, as compared to the other seal materials involved in the tests. The HDPE polymer seal gave the lowest weight loss in the tests. Clear differences in corrosion wear resistance were found between tested thermal spray coatings. Clearly the best performance was achieved with plasma sprayed chromium oxide coating compared to the other tested coatings when glass fibre reinforced teflon was used as the seal material.