Plastometer, parallel-plate

Figure 10.1 Parallel-plate plastometer for determination of consistency.

The consistency depends on the powder/liquid ratio used to mix the cement, and the parallel plate plastometer can be used to determine the optimum ratio for a particular cement system. 

A type of parallel plate plastometer developed in Germany it differs from the conventional parallel plate instrument in that it measures the load required to deform the test sample by a specified amount in a fixed time. 

The earliest and best-known of parallel plate plastometers. The original model has been... 

Flow properties Parallel plate plastometer, Disc-cure method A—>B 30,31... 

Gartling, D.K. and Fhan-Thien, N. (1984), "A Numerical Simulation of a Hastic Fluid in a Parallel-Plate Plastometer", J.Non-NewtoniM Fluid Mech.. 14.347-360. Lipscomb, G.G. and Denn, M.M. (19iS4), "Flow of Bingham Fluids in Complex Geometries", J. Non-Newtonian Fluid Mech..l5.337-346. 

Pantile. A single-lap roofing tile having a flat S-shape in horizontal section. Details of clay pantiles are specified in B.S.1424 the minimum pitch recommended is 35°. Parallel-plate Plastometer. See williams plastometer. 

Whiting, R and Jacobsen, P.H. (1979) The evaluation of non-Newtoiuan viscosity using a modified parallel-plate plastometer, /. Mat. Sci., 14, 307-11. 

Kataoka, T., Kitano, T. and Nishimura, T. (1978) Utility of parallel-plate plastometer for rheological study of filled pol)rmer melts, Rheol Acta, 17, 626-31. 

The expression for calculating the apparent yield stress in a parallel-plate plastometer is... 

The parallel plate plastometer is usually run with a sample much smaller than the plates (see Figure 7.3.2). In this case the sample radius changes with time, but sample volume between the plates V is constant. This leads to (Gent, 1960)... 

Melt viscosity, or flow, is typically measured using extrusion plas-tometers (or melt indexers), capillary rheometers, and parallel plate rheometers. The extrusion plastometer measures the flow of a polymer melt under conditions specified by ASTM standard D 1238. This test yields a single, low-shear-rate value which is typically used to specify resins. Capillary rheometers determine viscosity over a range of shear rates in channel flow. While they are subject to error, these rheometers are still the only means of measuring viscosity at high shear rates (typically -y > 1000 s i). Parallel-plate rheometers also measure viscosity over a range of shear rates, but the maximum allowable shear rate is about 100 s i. 

Williams Plastometer. A parallel-plate compression apparatus designed by I. Williams (Industr. Eng. Chem., 16, 362, 1924) for the testing of rubber it has since been used quite considerably in the testing of clay. 

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