KraussMaffei Berstorff has developed a new version of its 36D twin screw extruder with single venting. The machine is equipped with multi-component gravimetrics that helps pipe manufacturers to combat rising material costs.
“We have equipped the innovative machine concept with multi-component gravimetrics with up to six components, three of which can be added gravimetrically or volumetrically,” explains Michael Hofhus, Head of the Pipe Extrusion Product Group at KraussMaffei Berstorff. The concept permits comprehensive metering of cost-cutting material mixtures. With gravimetric weighing, highly filled dry blends up to 100% of the total output, regrinds and regranulates up to 20% of the total output or even pure chalk up to 40% of the total output can be processed, mostly for waste water pipes, according to the machinery supplier.
Using volumetric metering, micro granulate blow agents, up to 3% of the maximum output depending on the application, can be added for the production of, for example, foam core pipes or paint master batches up to a maximum of 5%. The system is equipped with a corresponding storage container and a vacuum hopper for this application. It is also possible to prevent PVC residue clogging the extruder when the system is shut down by adding so-called purging compounds.
“In addition to the huge competitive edge which customers achieve thanks to the high level of flexibility, they also benefit from very simple material conveying and handling,” adds Mr Hofhus. The complicated mixing procedure required in standard systems is not needed in this case. The concept also prevents segregation of the material. The material handling process is designed flexibly, so that the individual component proportions of the mixture can be changed at any time.
The processing concept of 36D twin-screw technology with single venting also ensures safe material degassing. The tungsten-carbide coated process unit provides reliable wear-resistance which is necessary for the processing of highly filled materials. The metering system can be used for pipe production, as well as for sheeting and profile production and granulation.
KraussMaffei Berstorff says several machines with this configuration and different sizes were recently installed at Hakan, a waste water pipe producer based in Turkey.