Viscometers parallel-plate

As with dilatometry, specimen sizes are relatively large. As a result, temperature gradients within the specimen become a concern, especially considering the exponential temperature dependence of viscosity. The two parallel plates are usually 

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Parallel Plate Viscometer. In parallel plate viscometers (164) the gap width usually is larger and can be varied freely. This is an advantage when measuring suspensions or dispersions with large particles or with a tendency to fly out of the gap. The wide gap means that there is less sensitivity to... 

A. W. Chow, S. W. Sinton, J. H. Iwa-miya, T. S. Stephens 1994, (Shear-induced particle migration in Couette and parallel-plate viscometers NMR imaging and stress measurements. Phys. Fluids 6, 2561. 

A parallel-plate viscometer with a geometry such as shown in the lower left corner of Figure 2 is filled with a polymer melt of 10" P. What force is required to move the plates parallel to one another at a velocity of 1 cm/s if the spacing of the plates is 0.1 in. and their area is 1 in.2 ... 

Parallel plates, flow between, 15 720t Parallel plate viscometers, 21 735-736 Parallel-pore model, 25 306 Parallel pores, 25 301 Parallel synthesis, microwaves in, 16 549-552... 

Figure 7.6 Two example LVDT stages offered by Theta Industries. Top constant force system, used for vertically mounted dilatometers and parallel plate viscometers. Bottom horizontally mounted dual pushrod system with leaf springs.

Such a device is referred to as a parallel plate viscometer , where the rate of compression of a glass pellet between two (alumina) parallel plates is proportional to its viscosity. See section 10.4.1. 

As shown in Figure 10.9, the parallel plate viscometer involves measuring the rate of compression of a fluid between two paral-... 

A. N. Gent, Theory of the Parallel Plate Viscometer , British Journal of Applied Physics, 11 (1960). 

N. H. Burlingame, A. K. Varshneya, and K. Freders, Viscosity Measurement of NIST Soda-Lime Standard 710A Glass Using a Parallel Plate Viscometer , Report to the Industry-University Center for Glass Research, Alfred University, Alfred, NY (1990). 

Parallel plate viscometers are used for very high viscosities at low shear rates. Measurement of shear rate is difficult. 

Parallel Plate Viscometer, This instrument resembles the cone and plate viscometer, except that it has a flat horizontal rotating plate in place of the cone. The shear rate within the narrow gap of the two plates is not as uniform as for the cone and plate viscometer. The limiting shear rates for the parallel plate viscometer are similar to those of the cone and plate instrument. This type of a viscometer is suitable for rheological measurements of suspensions and emulsions. 

A number of other methods are occasionally used for viscosity measurements. The most common are the parallel plate viscometer, used in the 10 -10 Pa s range, the penetration viscometer, used in the 10 -10 Pa s range, and the torsion viscometer, used in the lO -lO " Pas range. Although each of these methods has advantages under specific conditions, none have gained wide acceptance in the glass community. 

Parallel-plate viscometer n. (1) An instrument consisting of two circular parallel plates, the lower one stationary, the upper one rotatable, the disk-shaped specimen being confined between the plates. An example of this type of viscometer is the Mooney viscometer. 

For the range of values encountered with colloidal suspensions, a concentric cylinder rotating viscometer is often used to measure the viscosity. Less often used are the cone and plate viscometer and the parallel plate viscometer. For liquids and solutions, a capillary viscometer is often used. Information on several types of viscometers can be found in Ref. 55. 

Somewhat higher viscosities, up to 10 poise or so, are measured using a parallel plate viscometer (see ASTM C1351M-96). In the parallel plate viscometer, a suitably sized disk (about 8 mm in diameter by 3 to 6 mm thick) of glass is sandwiched between two parallel plates (inconel plates covered with platinum foil or thin alumina substrates). The top plate is loaded with known weights. Viscosity can be calculated by measuring the rate of decrease in the thickness of the specimen with a linear variable differential transformer (LVDT) device. 

The change in the viscosity of the system upon nanosilica reinforcement was analyzed as a function of the filler content. The viscosity measurements were performed on a parallel plate viscometer from Couette-System/MetllCT-Toledo GmbH. The viscosity change was monitored between room temperature and 100°C. 

High viscosities, more than 10 Pa s,canbesatisfactorilymeasuredinthecommercialTMA and it is in this region that the glass-forming liquid is typically shaped. Table 10.2 summarises the way in which TMA has been used for beam bending, indentation and parallel-plate viscometers to cover the viscosity range 10 - 10 Pa s. The TMA indentation and parallel-plate viscometry are described in detail below (Section 10.5.5 and 10.5.6, respectively). 

If 0.500 cm3 polymer described by the following model is placed in a parallel plate viscometer with a plate separation of 0.0100 cm and a weight of 0.500 g is applied to the movable plate by appropriate pulleys, how far will the plate move in 10 s (x in Pa). 

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