Rheometer slit orifice

This rheometer is similar in all respects to that discussed in section 3.2.1 except for the fact that it has a slit orifice cross-section rather than a circular one. The major credit for the development of the concept and use of this rheometer goes to Han [69,71,72] though others [73] have also used it for polymer melt studies. The instrument makes use of a series of flush mounted transducers located along the flow channel wall which measure the pressure gradients along the flow direction. These are then converted into wall shear stress values [69] as follows ... 

Constant Plunger Speed Slit Orifice Capillary Rheometer... 

These capillary rheometers are principally the same as those described in Sections 3.2.1 and 3.2.2 except for the melt transport system which is of the screw extrusion type rather than the plunger type discussed earlier. A schematic diagram of an extrusion capillary rheometer is shown in Fig. 3.5. Commercially available extrusion capillary rheometers are the Haake Rheocord (Haake Buchler Instruments, Inc., Saddle Brook, NJ) and the Brabender Plasticorder (Brabender, Duisburg, Germany). The rheological property measurements can be done using a circular or slit orifice, as these are separate attachments for the miniaturized single screw extruder. 

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