Cone plate viscometerThe testing principle is based on the flow characteristics of fluids under shear force, and infers their viscosity values by measuring the flow behavior of fluids under specific conditions. The operating points include instrument preparation, sample processing, parameter setting, measurement process, and instrument maintenance. The following is a detailed introduction:
Test Principle
A cone plate viscometer typically consists of a fixed conical section and a rotatable flat section, forming a narrow fluid channel between the two. When the fluid is placed between a conical plate and a flat plate, and the plate rotates, the fluid flows under the action of shear force. According to the Poisson formula (τ=μ * γ, where τ is the shear stress, μ is the viscosity, and γ is the shear rate), the viscosity value can be inferred by measuring the torque required to rotate the plate. The higher the viscosity of the fluid, the greater the required torque. By measuring the torque values at different speeds, a torque speed curve can be plotted to calculate the viscosity of the fluid.
Key Operating Points
Instrument preparation
Clean the viscometer and adjust the two horizontal adjustment feet until the water bubble at the top of the rotating viscometer is in the center position.
Install the rotor protection frame of the viscometer onto the rotating viscometer.
Screw the selected rotor into the connecting screw.
Plug in the power and turn on the switch button behind the viscometer.
Enter the selected rotor number and ensure that the screen displays the selected rotor number.
Sample processing
Select representative test samples according to relevant standards (such as GB/T 3186).
Check and prepare the test samples to ensure that there is no precipitation or layering tendency when the samples are left to stand. If there is any, they should be stirred thoroughly and evenly. During the stirring process, do not mix bubbles, and there should be no impurities or clumps in the samples.
The sample size should be sufficient to fully fill the gaps between the cone plates. Generally, the sample size used for cone plate viscometers is below 1ml.
Parameter Settings
Select the appropriate speed, press the "Speed" key to set the speed, and use the TAB key to gradually shift to the ten, one, and ten digits of the current displayed speed. After selection, use the numeric increase or decrease keys to set the speed size of the ten, one, and ten digits. After setting the speed, press the speed key to confirm.
measurement process
Rotate the knob of the lifting frame to slowly lower the viscometer, and gradually immerse the rotor into the measured liquid until the mark on the rotor is level with the liquid surface. Adjust the position of the viscometer to horizontal.
Press the measurement button, and the stepper motor will start rotating. After a suitable period of time, the current rotor, viscosity value at that speed, and percentage scale can be measured simultaneously.
During the measurement process, if the rotor needs to be converted, you can directly press the reset button.
instrument maintenance
After the measurement is completed, press the reset button and turn off the power switch at the same time.
Remove the rotor of the cone plate viscometer and clean the rotor, instrument, and test bench thoroughly.
Regularly inspect and calibrate instruments to ensure the accuracy of measurement results.