Teningen, Germany - A well-known German manufacturer of industrial pumps has built a pump housing of polyurethane instead of cast iron for the first time, according to PU housing specialist Thieme GmbH & Co. KG.
"There were a number of good arguments in favour of polyurethane," for the pump maker's first attempt to produce a housing of plastic, said Thieme project director, Jürgen Vogel, in a company statement.
"One is that custom RIM parts made of PU are considerably lighter, without having any restrictions on their technical properties; and another is that the production and tool costs are considerably lower than for a cast iron housing."
Thieme's moulded polyurethane parts met all the functional and material specifications for the task, and at the same time, production costs were significantly lowered. With the change of material, the German pump manufacturer has also strengthened its position as a technology leader, said Teningen-based Thieme.
Typical uses of such pumps are in waste water and environmental technology, in the chemical and food industries and in hygiene applications, to convey a wide range of fluids and mixed fluids/solids.
Such diverse applications put tough demands on the mechanical strength, thermal and chemical resistance and the hygienic properties of the materials used, Thieme points out.
As an example, the housing must withstand pressures of up to 18 bar and temperatures of up to 60°C without deformation, and resist constant contact with salt water and chemically aggressive media.
Thieme selected Baydur GS from Bayer MaterialScience, to maximise mechanical strength and chemical resistance. Its high impact strength, rigidity, resistant to heat and chemicals and to rotting were all considered valuable attributes. Custom RIM parts of such PU materials are a potential alternative to cast metal parts of aluminium, zinc, steel or cast iron, and are up to 50 percent lighter.
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