Views:3 Author:Site Editor Publish Time: 2020-01-17 Origin:Site
The kinematic viscosity measuring instrument is a new type of instrument that has appeared in recent years for determining the kinematic viscosity of liquid petroleum products. What types of Kinematic viscosity meters are there? Why do we need it? How should a kinematic viscometer be used correctly?
Type of kinematic viscometer
Why do I need a kinematic viscometer?
How to use the kinematic viscometer
Kinematic viscometer considerations
There are many ways to express the viscosity, which can be roughly divided into two categories: the viscosity directly measured by the viscosity definition is called "absolute viscosity", such as dynamic viscosity, kinematic viscosity and the like. The viscosity measured when compared to a liquid of known viscosity under certain conditions is referred to as "relative viscosity" or "conditional viscosity", such as Enes viscosity. According to the measurement method, the viscosity is generally classified into three types: dynamic viscosity, kinematic viscosity, and Enshi viscosity.
In practical engineering and industrial production, it is often necessary to check the viscosity of the fluid online to ensure the best process operating environment and product quality, thereby improving production efficiency. By measuring the viscosity of the liquid in the process, the data of the rheological behavior of the liquid can be obtained, which has important guiding value for predicting the process control of the product process, the transportability and the operability of the product in use. The properties of the liquid are often related to other properties of the product such as color, density, stability, solid content and molecular weight. The most convenient and sensitive way to detect these properties is to use a Kinematic viscosity meter to measure the viscosity of the liquid online. In-line viscosity testing in the production process according to the scope of process technology requirements, can minimize the scrap rate of the product and the downtime of the production line.
1. Kinematic viscometer machines must be kept horizontal
2. Avoid the generation of air bubbles when the rotor is placed in the sample, otherwise the measured viscosity value will be reduced. The method to avoid is to tilt the rotor into the sample, and then install the rotor. The rotor cannot touch the cup wall and the bottom of the cup and is measured. The sample must have not passed the specified scale.
3. When measuring different samples, the rotor must be kept clean and dry. If there are other samples remaining in the rotor or residual water after cleaning, the accuracy of the measurement will be affected.
4. The maximum acidity (PH) should not exceed 2. If the acidity is too large, special rotor should be used. When using ULA, the sample volume should be determined (only 16ml).
5. The viscosity standard is selected according to the measured viscosity range, and the instrument is verified before each use of the kinematic viscometer or rheometer, or periodically to ensure the accuracy of the measurement. It can provide the properties of Newtonian fluid in each viscosity range. The silicone oil or oil standard, accuracy ± 1%, the recommended life of the viscosity standard is one year from the opening.
6. When connecting the rotor, gently lift and hold the mandrel (on the main unit) with your left hand, and rotate the rotor with your right hand. This operation is to protect the mandrel and the spring wire in the fuselage, which can extend the service life of the kinematic viscometer.
7. The value should be stable when the value is stable, otherwise the value obtained will have a large error.
The performance index of the kinematic viscometer must meet the requirements of the national metrological inspection regulations. The instrument in use should be periodically checked. If necessary (the instrument is used frequently or in a qualified critical state), an intermediate self-check is performed to determine that the metering performance is acceptable, and the coefficient error is within the allowable range, otherwise accurate data cannot be obtained.
Use a kinematic viscosity measuring instrument to pay special attention to the temperature of the liquid being measured.. Many users ignore this point and think that the temperature difference does not matter. Our experiments prove that when the temperature deviation is 0.5 °C, some liquid viscosity values deviate by more than 5%. The temperature deviation has a great influence on the kinematic viscometer, the temperature rises, and the viscosity decreases. Therefore, special attention should be paid to keeping the temperature of the liquid to be measured near the specified temperature point. It is best not to exceed 0.1 °C for accurate measurement.
The selection of the measuring container (outer tube). For the kinematic viscosity meter, carefully read the instrument manual, and the different rotors (inner cylinders) match the corresponding outer cylinders, otherwise the measurement results will be greatly deviated. For a single cylinder rotational viscometer, in principle, the radius of the outer cylinder is required to be infinite, and the actual measurement requires that the outer cylinder, that is, the inner diameter of the measuring container is not lower than a certain size.
The depth of the rotor immersed in the liquid and the effect of the bubbles. The kinematic viscometer has strict requirements on the depth of the rotor immersed in the liquid, and must be made in accordance with the requirements of the specification (some double-tube instruments have strict requirements on the amount of liquid to be tested, and must be measured by a measuring cylinder). In the process of immersing the rotor in the liquid, there are often bubbles. Most of the time after the rotation of the rotor, the air bubbles will disappear. The bubbles attached to the lower part of the rotor sometimes cannot be eliminated. The presence of the air bubbles will cause a large deviation in the measurement data, so the tilt Slowly immersing the rotor is an effective method.
Cleaning of the rotor. It should be cleaned in time using a Kinematic viscosity measuring instrument and free of dirt, and should be cleaned in time after measurement, especially after measuring paint and adhesive. Pay attention to the cleaning method, soak it with a suitable organic solvent. Never use a metal knife or other hard scraping, because there will be deviations in the measurement results when there are severe scratches on the surface of the rotor.
In any case, whether or not the standard kinematic viscometer is selected has the greatest impact on the final measurement. If you are looking for a reasonably priced high quality kinematic viscometer, NANJING T-BOTA SCIETECH INSTRUMENTS&EQUIPMENT CO.,LTD can provide you with the best products.