Slot Die for Rosand Capillary Rheometers

The benefit of slot die rheometry is that the Bagley correction is not required to obtain the true shear stress. Pressure is measured along the slot geometry using up to three flush mounted pressure transducers, which enables direct determination of the shear stress.

For equivalent polymer volumetric flow rates, slot die rheometry will yield lower maximum shear rates than those of capillary rheometry, but consistent with those expected in extrusion rheometry. It is a modular construction allowing easy use of different slot die measuring geometries. The slot geometry itself is machined into a changeable insert, meaning that only the insert has to be changed if a variation in either slot height or width is required. This construction allows great flexibility over slot dimension and thus shear rate.