Stability analyzerIt is a precision instrument designed specifically for stability control and formulation research of liquid samples, widely used in fields such as medicine, cosmetics, food, petroleum, and chemical engineering. The core principle is based on multiple light scattering technology, which quantitatively analyzes the particle size distribution, concentration changes, and unstable phenomena (such as stratification, flocculation, and sedimentation) in the sample by measuring the changes in transmitted and backscattered light intensity. High precision detection can be achieved without diluting the sample.
Stability analyzerDetailed operation guide:
1、 Preparation before the experiment
Environmental and equipment inspection
Place the falling ball viscometer on a horizontal, stable, and vibration free experimental platform.
Check if the glass tube is clean, free of cracks or scratches.
Prepare standard measuring balls (usually made of glass or stainless steel), clean them thoroughly with solvents (such as ethanol) and lens paper, and dry them with compressed air or air.
Constant temperature water bath setting
Immerse the outer sleeve (or the entire instrument) of the falling ball viscometer into a constant temperature water bath.
Set the water bath temperature to the desired temperature for the experiment (such as 25.0 ° C, 40.0 ° C, etc.), ensuring that the temperature fluctuation is ≤ ± 0.1 ° C.
Preheating: Allow the instrument and water bath to equilibrate at the set temperature for at least 30 minutes to ensure uniform temperature throughout the entire system (including the liquid being tested).
Sample preparation
Take an appropriate amount of the liquid to be tested and use vacuum or ultrasonic treatment for degassing to remove bubbles from the liquid. Bubbles can seriously interfere with the falling of the ball.
If necessary, measure the density of the liquid (ρₗ) for subsequent viscosity calculations.
2、 Sample loading
Clean capillary tube
Rinse the inside of the drop tube with a suitable solvent (selected according to the properties of the sample, such as petroleum ether, acetone, ethanol), and then blow dry with dry hot air or nitrogen.
Inject liquid
Slowly inject the liquid to be tested into the drop tube through a funnel or syringe to avoid the formation of bubbles.
The liquid should be filled slightly above the upper timing mark line.
Carefully insert the rubber plug or sealing cover to ensure a good seal and no air bubbles remain above the liquid level.
Place the ball
Gently place the clean and dry ball into the liquid through the top opening of the capillary tube.
Quickly invert the drop tube (180 °) and let the ball slide to the other end of the tube (now the upper end).
Stand the dropper upright again (return to the measurement direction), and the ball will be in the starting position at the top, ready to fall.
3、 Measure the falling time
Adjust the direction of the instrument
If it is a tilted ball viscometer (such as H ö ppler viscometer), adjust the instrument to the specified tilt angle (such as 80 °).
If it is vertical, ensure that the instrument is strictly vertical.
Start timing
When the lower edge of the ball passes the upper timing mark line, immediately start the stopwatch (or trigger the automatic photoelectric timer).
Stop the stopwatch immediately when the lower edge of the ball passes the lower timing marker line.
Record the time t (in seconds) required for the ball to fall a fixed distance.
repeated measures
Repeat the inversion upright process and restart the measurement.
Repeat the measurement at least 3-5 times and record the falling time for each measurement.
Calculate the arithmetic mean of time, t_avg. If a data deviation is too large, it should be discarded and retested.
4、 Cleaning and Closing
Pour out the sample
After the measurement is completed, invert the dropper again and let the ball slide to the top.
Be careful when taking out the ball.
Pour the liquid out of the tube.
Thoroughly clean
Immediately rinse the inside of the drop tube with a suitable solvent to remove residual samples.
Blow dry with dry hot air or nitrogen.
Clean the ball thoroughly and store it properly.
Turn off the device
Turn off the constant temperature water bath.