Rolling ball viscometer

Rolling ball viscometers, 21 738 Roll mills, 16 722 Rolls, high pressure, 16 612-613 Romanechite, 15 540 Romascone, 24 571 Romet-30/Romet-B. See Ormetoprim ROMP catalysts, 17 707, 708 ROM polymers. See also Ring-opening metathesis (ROM) polymers, 26 947-948 Roof coatings... 

The rolling-ball viscometer shown in Fig. 4.3-32 is designed for pressures up to 200 MPa and temperatures of 250°C. It consists of a standard viscometer made of glass (1), which is arranged inside a high pressure autoclave (2). The autoclave is heated by silicone oil in a jacket (3). When the steel ball (4) passes the measuring coils (6) a timer is started. From the rolling time between the coils the viscosity can be evaluated [46]. 

Transforming the cell to a rolling-ball viscometer makes y constant, but if the device is to be used as a viscometer one must also show that eqn (3.9.2) remains valid even when nonhydrodynamic interactions with the walls, such... 

To measure the absolute viscosity eqn (3.9.2) must be solved, and so a value of y is needed. The discussion above indicates the conditions necessary to produce a constant wall correction, but there are unknowns, such as the sphere-to-wall separation, which make it impossible to calculate an actual theoretical value with sufficient accuracy. One must measure y empirically by observing the sphere velocity under conditions for which the fluid viscosity is known. For the rolling-ball viscometer, comparison is made with ambient-pressure viscosities whereas high-pressure data taken by the rolling-ball viscometer are used for comparison for the centrifugal-force viscometer. 

This procedure describes the use of a DAC rolling-ball viscometer which is useful in the range 0.5 77 10 m Pa s. As explained in the text, the pro-... 

Fig. 3.51 The high-pressure viscosity of ( , o) methanol and ( , ) 1,2-propanediol. The filled data points were obtained with a rolling-ball viscometer and the open data points were obtained with a centrifugal-force viscometer, the curves are a free-volume fit (Fig. 3.53). Methanol data, for pressures up to 3 GPa obtained by (x) Bridgman and (-I-) Herbst eta/. are in excellent agreement with our results. Crystallization of the methanol sample limited measurements to 8.3 GPa while the maximum viscosity for 1,2-propanediol limited the experimental pressure to 2.9 GPa.

This procedure describes the use of DAC centrifugal-force viscometers which are useful in the range 10 s 10 Pa s. Viscosities from DAC rolling-ball viscometers (see Protocol 2) are used here to convert the measured relative viscosities into absolute values. Loading of the DAC with a ruby manometer chip, a nickel sphere, and the experimental fluid is described in Protocol 1. 

Place the DAC into the optics of the rolling-ball viscometer and record the position of the sphere relative to the gasket hole s edge. Remember, that the direction for this must be along the direction selected in step 1. Use the difference between the starting and final sphere positions in eqn (3.9.4) to calculate rjlycent- Use the procedure described in the text to calculate ycem-... 

McNown, J. S., Analysis of the rolling ball viscometer. Mich. Eng. Coll. Ind. Program, Brochure lP-160. Univ. of Michigan, Ann Arbor, Michigan, 1956. McNown, J. S., Lee, N. M., McPherson, M.B., and Engez, S. M., Proc. 7th Intern. Congr. Appl. Mech., London, 1948, Vol. 2, Part I, p. 17 (1948). (Reprinted as State University of Iowa, Reprints in Engineering, Reprint 81). 

Figure 20 ScheniBlic rqncsencaiion of (a) a falling batl viscometer and (b) a rolling-ball viscometer.

The falling-ball and the rolling-ball viscometers, shown in Fig. 20, are also simple devices for viscosity measurement. However, they do not qualify as rheometers but as indexers. 

PrtKess control and product quality coniroL These procedures are generally carried out using simple devices when only an assessment of viscosity is required. Capillary, falling- or rolling-ball viscometers, infinite sea viscometers (a rotating cylinder immersed in the sample), and free-fall... 

ROLLING BALL VISCOMETER FOR USE AT TEMPERATURES TO 400 C UNDER PRESSURES TO 5 KILOBAR. 

AN EXPERIMENTAL COMPARISON OF A ROLLING BALL VISCOMETER AND A CAPILLARY VISCOMETER AT ELEVATED PRESSURES. M.S. THESIS. 

THEORY OF INCLINED-TUBE AND ROLLING-BALL VISCOMETERS. 

These equations can be used for the rolling ball viscometer [2], see figure 3. ------------------------------ ... 

A high pressure rolling-ball viscometer up to IGPa. Jpn. J. Appl. Phys., 25. 1091-1096. 

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