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What are the factors affecting the result of rotational viscometer verification?

- May 23, 2018 -

Factors Affecting Verification Results of Rotational Viscometer


Standard Viscosity Temperature Effects The standard viscosity fluids we generally use are Newtonian fluids. Its characteristic is that the viscosity value will change with the temperature. The lower the temperature, the higher the viscosity. We prove in actual testing: When Deviation of the viscosity of the liquid temperature ± 0.5 °C, some of the standard liquid viscosity deviation will exceed 5%, (such as: GBW13607 standard viscosity liquid) that is, the temperature increases, the viscosity of the standard viscosity of liquid viscosity will drop. Therefore, special attention should be paid to the time of detection. It is very important to keep the temperature of the standard viscosity fluid constant within (20±0.1)°C.


Effects of dirt on the rotor Rotary viscometers in use have dirt attached to most rotors, so they must be cleaned with acetone, ethanol, or aviation gasoline before the test. Then rinse with distilled water and dry before checking. If the rotor is adhered with paint or adhesive, do not scrape the rotor or outer cylinder with a metal blade during cleaning. This can cause scratches on the surface of the rotor and the outer cylinder, which can also cause measurement errors.


Improper selection of the rotor and speed The rotating viscometer uses a dial plus pointer to read the value. The stability of the verification result and the reading deviation are combined together to have 0.5 squares, but if the read out value is biased Hours, then the relative error caused will be above 10%.


The influence of bubbles in the standard solution When we inject the external cylinder into the standard viscosity solution or when the rotor is immersed in the standard viscosity solution, bubbles are often generated. The standard viscosity solution should be injected into the external cylinder and placed in a constant temperature bath for a constant temperature of 24 hours. Allow the bubbles in the standard viscosity solution to slowly disappear. When the rotor is put into the standard viscous liquid in the outer cylinder, a large number of bubbles are often generated. Generally, a large part of the rotating viscometer rotor floats and disappears after a certain period of time, but a small amount of air bubbles often attached to the bottom of the rotor cannot Eliminated, the bubbles in the viscous liquid will also directly affect the accuracy of the measured value. Therefore, we immersed the rotor slowly and slowly into the viscous liquid, which will control the generation of the bottom bubble, making the measured value more accurate and also greatly improving our working efficiency.

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