How do you find the viscosity of a rotational viscometer?
Rotational viscometers measure the viscosity of the sample by turning a spindle in a cup. The viscosity is determined through the measurement of the torque on a vertical shaft that rotates a spindle.
What do you calculate from viscometer?
A viscometer (also called viscosimeter) is an instrument used to measure the viscosity of a fluid. For liquids with viscosities which vary with flow conditions, an instrument called a rheometer is used.
Which viscometer is considered a rotational type?
2 Couette Viscometer. The most popular rotational viscometer is the Couette concentric-cylinder viscometer. Fluid is placed in the annulus between two concentric cylinders (regarded as infinite in the interpretation of data), which are in relative rotation about their common axis.
How is viscometer constant calculated?
The calibration constant for the viscometer at 100°C can now be calculated using the same equation. Viscometer No. (cP) multiply the kinematic viscosity in mm2 /s( cSt) by the density in grams per milliliter.
What causes thixotropy?
Thixotropy arises because particles or structured solutes require time to organize. Some fluids are anti-thixotropic: constant shear stress for a time causes an increase in viscosity or even solidification. Fluids which exhibit this property are sometimes called rheopectic.
What does rotational viscometer measure?
Rotational viscometers are designed to measure viscosity by analyzing the torque required to rotate a spindle submerged in a fluid at a constant speed. The continuous rotation of the spindle ensures calculations are made over time, allowing time-dependent fluid analysis.
What is a Cannon Fenske viscometer?
The Cannon-Fenske Opaque Viscometer measures kinematic viscosity of transparent and opaque Newtonian liquids according to ASTM D445, ISO 3104 and ASTM D2170. This is a calibrated viscometer which include a certificate of calibration and instruction sheet.
How do you use a Cannon Fenske viscometer?
To charge the sample into the viscometer, invert the instrument and apply suction to tube G, immersing tube A in the liquid sample, draw the liquid into the capillary F. Adjust the liquid to mark E, turn the instrument to its normal vertical position and wipe clean.
How thixotropy is measured?
Thixotropy can be quantitatively measured using a rotational rheometer. The most commonly used testing geometries are 20-40 mm parallel plate or a cup/rotor geometry.
What is thixotropy Slideshare?
Definition of Thixotropy: It is the decrease in viscosity as a function of time upon shearing, then recovery of original viscosity as a function of time without shearing.
