In-line rheometer

for meltfor plastics

Shear- and elon­ga­tional vis­cos­ity com­bined In order to con­stantly mon­i­tor the melt qual­ity the de­ci­sive pa­ra­me­ters have to be mea­sured dur­ing the process. So far only sin­gle points could be checked along the vis­cos­ity curve by means of on­line mea­sure­ments (with­out melt flow­ing back into the process). With the Leistritz elon­ga­tional rheome­ter you have more op­tions: First of all, it is the first In­line-Rheome­ter ever (with melt flow­ing back into the process), which com­bines mea­sur­ing shear and elon­ga­tional vis­cos­ity! The rheometer facilitates online measuring of the shear viscosity with shear rates in the range of 10 to 10,000 s-1 and the elongational viscosity with elongation rates in the range of 5 – 75 s-1. It has a newly developed, patented die geometry with a hyperbolic narrowing that generates a constant elongational flow. This has not been possible with current online measurement devices. During a continuous measuring process, the operator can query two measured values of shear viscosity and one measured value of extensional viscosity in the according, precisely defined shear and expansion ranges at the same time. Operating principle During the extrusion process, a small amount of the melt flow is channeled off via a bypass system and pushed through the rheomter's slot die. After the measurement the material is transfer-red back into the process without losing any material. The melt flow can manually be diverted outwards, e.g. for determi-ning the melt density. However, if sensitive material is being pro-cessed, the melt flow can also permanently be diverted outwards.