Although the Kinematic Viscosity Test Equipment has a high degree of automation and greatly reduces human operation errors, sample pretreatment is still a key prerequisite for ensuring accurate and reliable test results.
The main purpose of sample pretreatment is to remove impurities and interference factors that may affect viscosity measurement, ensuring that the properties of the sample itself are stable and uniform before testing.
1. Filtration
Remove mechanical impurities such as solid particles, dust, fibers, etc. from the sample. These impurities can clog the precision capillaries, valves, and flow paths of the instrument, leading to measurement errors and even instrument malfunctions.
2. Dehydration and impurity removal
Remove moisture and light volatile components from the sample. Moisture can alter the chemical properties of the sample, especially at high temperatures where it may form emulsions or undergo hydrolysis, severely affecting viscosity values. The presence of bubbles can greatly interfere with the flow behavior of liquids in capillaries.
3. Degassing
Remove air or other gases dissolved in the sample. Dissolved gases may precipitate during the testing process due to temperature or pressure changes, forming tiny bubbles. These bubbles can significantly affect the flow characteristics of the liquid, resulting in significantly low and unstable viscosity measurements.
4. Preheating/Pre constant temperature
Bring the initial temperature of the sample close to the testing temperature. Although the instrument itself has a precise constant temperature bath, if a bottle of low-temperature sample is directly placed in it, it takes a long time to reach the testing temperature equilibrium inside the sample, greatly prolonging the testing time and possibly inhaling air or generating condensation water again during the waiting process.
5. Additional processing for special samples
Samples containing insoluble substances or precipitates need to be separated by centrifugation, and the upper clear liquid should be taken before filtration and other steps.
Viscous or semi-solid samples: They need to be heated at a certain temperature to fully flow and homogenize, and then filtered and degassed. But it is necessary to avoid overheating that may cause oxidation or decomposition of the sample.
Volatile samples: The processing process should be rapid and carried out in a closed container to prevent loss of volatile components, otherwise it will alter the composition and viscosity of the sample.