VPZh, VZ viscometer, March, Brukfild,

The viscometer (from armor. viscosus — viscous) — the device for determination of viscosity of substance. Viscosity is measured in puaza.

Capillary viscometers

The principle of action is based on calculation of time of course of the set liquid volume through a narrow opening or a tube, at the set difference of pressure. Most often liquid follows from the tank under the influence of a body weight, in that case viscosity is proportional to a difference of pressure between the liquid following from a capillary and the liquid at the same level following from very thick tube. By means of the capillary viscometer are measured viscosity from 10 mkpas (gases) to 10 kpas. Use viscometers on ASTM D 445(GOST 33).

Rotational viscometers

Two bodies of rotation identical or different, are combined on axes so that one of them touches another from within (the sphere entered in a cone can serve as an example). The space between bodies is filled with the studied substance, and to one of bodies the torque moves, the body begins to rotate with the angular speed depending on viscosity of substance (at viscometers the speed of rotation is, as a rule, stabilized and the torque is measured). Range of operation of standard viscometers stretches from 1 MPa · with to hundreds of thousands of Pas · with [1]. Such wide range of measurements is achievable due to change of speed of rotation of a spindle from 0,01 revolutions per minute to 100, and also due to use of spindles of the different sizes at different ranges of viscosity.

The viscometer with a moving ball

The viscometer is based on Stokes's law. Viscosity is determined by passing time by a ball of a certain distance, most often under the influence of its body weight. Geppler's viscometer is most known.

The viscometer with the vibrating probe

It is based on change of resonant frequency of fluctuations in liquid of various viscosity. As frequency will depend also on density of the measured liquid, some models allow to determine this density irrespective of viscosity whereas others impolzut the set known value of density.