Excellent Chemical Resistance
The company Legrom GmbH from Schwäbisch Hall manufactures segment hose systems, including various accessories such as nozzles and couplings, under the brand name Legrom VARIO System. These segment hoses stand for efficient use on machinery, production lines and other equipment in a wide variety of industrial sectors, and are used as classic coolant and lubricant hoses or for transporting atmospheric and ionised air.
The LEGROM VARIO SYSTEM is available in three different diameter sizes and can be flexibly combined with each other, thanks to the high variability offered by adapters. In addition, one or more nozzles can be operated simultaneously by adding a junction to a single connection (see Fig. 1). The high flexibility of the individual segments enables free positioning and tight bend radii, so that the segment hose can be positioned exactly where it is to be used. High surface quality and long service life of machining tools, combined with high pressure to cut costs, require a thorough and targeted use of coolants and lubricants for turning, drilling, grinding or milling.
For some technical processes, such as soldering or electroplating, a high chemical resistance of the segment hoses is required, since acids and alkalis are used here. Furthermore, the use of segment hoses in livestock breeding and in disaster control requires increased media resistance to cleaning agents and disinfectants as well as to acids and alkalis in connection with the vapours and excrements produced by the animals. This increased chemical resistance cannot be achieved with the previously used plastic, polyoxymethylene (POM), so that LEGROM was forced to qualify new materials for these applications.
AKRO-PLASTIC was able to recommend a compound based on polyketone (PK), AKROTEK® PK-VM, thanks to its many years of experience in the plastics sector. The advantage of this material lies in its excellent chemical resistance to acids and alkalis on the one hand and its very good tribological performance on the other, so that the individual segments can be easily shifted against each other and the hose can therefore be positioned exactly.
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Polyketone can be processed on a standard injection moulding machine and, thanks to its high crystallisation rate, has shorter cycle times than POM.
The sum of all properties convinced Mr. Werner Reinhuber, Managing Director at LEGROM, to use this compound for segment hoses with an extremely high requirement profile.
Fig. 1: LEGROM VARIO SYSTEM segment hoses for the transport of coolant during milling