Method of determining the mixing end point of high viscosity materials
The mixing of high viscosity materials is often encountered in industrial production, and the mixing efficiency and mixing effect directly affect the quality and yield of finished products. The judgment of the mixing endpoint in the mixing time determination is the key, and different researchers have different methods to judge the mixing endpoint, and its accuracy varies. The following will list several mixing methods for high-viscosity mixtures.
1. Visual inspection of the mixing endpoint method
1.1 The method is to add the coloring substance with color in the mixture system, to ensure that the amount of the added substance added is small, neither chemical reaction with the system nor changes the nature of the fluid.
1.2 Then the color-changing substance is injected at a certain position in the system to observe the mixed flow condition of the system.
1.3 The time required from the start of the addition of the color-changing substance to the time when the color no longer changes is observed by the naked eye as the mixing time.
1.4 This method is suitable for measuring the mixing time of a neutral acid-base system in a transparent stirred tank, but the human error in measurement is large and the accuracy is low.
2. The use of image processing software to determine the mixing time method
2.1 The principle is similar to the visual method, except that the determination of the color of the mixing endpoint depends on the software for image analysis.
2.2 The use of digital cameras to take images at a certain frequency, through commercial software and the standard color to determine the end of mixing color, which can eliminate human visual errors.
2.3 This method can accurately measure the mixing time with high reliability and repeatability, and can also determine the location of the mixing dead zone.
3. The laser method of testing mixed endpoint method
3.1 Composition: laser light source, power meter, detection system and test probe.
3.2 Principle: The laser is emitted by the light source through the optical fiber, through the fluid into the light received by the optical fiber, the fluid color is different while receiving the laser light intensity is different, through the detection system test and record the change in light intensity with time, to determine the mixing endpoint and the mixing time.
3.3 Advantages: accuracy, simplicity and speed
3.4 Precautions: Because the fluid flow rate in different locations in the mixing tank is different, so the test probe is placed in different locations when the measured mixing time value is different, the actual mixing time often requires multi-point measurement and then averaged.
4. Conclusion
In addition to the above methods, LIF(laser-induced Fluorescence) test method and photodiode detection method are under further study and testing
