Abstract: On-line rheological measurements are made on a process flowing material, such as a polymer melt, utilizing a rheometer of the type in which an inlet pump delivers a relatively large volumetric flow of diverted process material from a process main stream to an inlet site located in very close proximity to the entrance of a capillary passage, and a metering pump draws a smaller portion of the volumetric flow of the diverted material from the inlet site through the capillary passage for return to the process main stream. The viscosity of the diverted material is measured as a function of the rate of flow of the material through the capillary passage and the pressure drop between spaced apart locations along the capillary passage.

Abstract: Apparatus and method for the simultaneous measurement of rheological and thermal characteristics of a test specimen subjects the test specimen to stress for rheological measurements, while at the same time subjecting the same test specimen to controlled temperature changes for the measurement of temperature differentials indicative of thermal characteristics of the test specimen while the test specimen is being stressed for the rheological measurements, and a measuring cell for measuring the thermal characteristics of a specimen.