Capillary viscometerthermostatic bathUnder strict adherence to operating standards, ensuring suitable environmental and equipment conditions, and selecting matching capillary viscometers and liquid media, the best performance is achieved. The specific analysis is as follows:
1、 Equipment conditions
Thermostatic bath performance:
The constant temperature bath should have a high-precision temperature control system, such as using PID automatic temperature control technology, to ensure that the temperature fluctuation is within a very small range (such as ± 0.005 ℃ to ± 0.01 ℃).
The constant temperature bath should have a good stirring system, such as internal circulation mode combined with motor stirring, to ensure uniform temperature field and eliminate temperature dead corners.
The observation window of the constant temperature bath should be transparent on all sides for easy observation of the sample status, and the constant temperature cylinder should be made of fully imported transparent material, which is beautiful and elegant.
Fixtures and accessories:
The constant temperature bath should be equipped with a new generation of universal fixtures, suitable for all capillary viscometers on the market, to ensure stable sample fixation.
The constant temperature bath can be equipped with a pneumatic sample suction and layout system, making the operation more convenient and effortless.
2、 Environmental conditions
Temperature range:
The working temperature range of the constant temperature bath should cover the temperature points required for the experiment, such as 0 ℃ to 100 ℃ or 5 ℃ to 80 ℃.
In low-temperature environments (such as below 5 ℃), alcohol or antifreeze should be used as the liquid medium; In high-temperature environments (such as above 80 ℃), high-temperature resistant media such as silicone oil should be used.
Environmental requirements:
The constant temperature bath should be placed in a sheltered and dry place, kept clean, and the electronic control part should not be damp.
There should be no strong vibration or electromagnetic interference around the constant temperature bath to avoid affecting temperature stability.
3、 Operating conditions
Sample preparation:
The capillary viscometer must be cleaned before use. Generally, it is washed repeatedly with a solvent that can dissolve the residue inside the viscometer, then washed with alcohol or gasoline, and then washed with fuming sulfuric acid or potassium dichromate solution for 2-3 hours. Finally, it is rinsed with tap water and distilled water. It is then placed in an oven and heated to around 150 ℃ for drying, or inverted at natural temperature for several days until it is evaporated.
The sample should be injected with standard solutions such as pure water or 10% NaCl solution for measurement to ensure the accuracy of the experimental results.
Operating standards:
Plug in the power, turn on the "power" switch and "cycle" switch to start the thermostatic bath.
Clamp the capillary viscometer vertically in the thermostatic bath to ensure that the capillary tubes are vertically adjusted to the left, right, front and base note.
Maintain a constant temperature for a certain period of time (such as 10 minutes) at the measured temperature, so that the sample temperature is consistent with the temperature of the constant temperature bath.
When starting the measurement, record the time required for the liquid level to move between the two circles of the capillary tube. Generally, repeat the measurement three times, with an error of no more than 0.2-0.3 seconds each time, and take the average value.
Safety precautions:
The constant temperature bath must be well grounded before use to ensure the personal safety of the operator.
Be careful when installing or removing the thermometer to avoid shattering it.
The liquid level in the bathtub should be kept at a certain height, not lower than 20mm below the workbench.
When the instrument is not used for a long time, the medium in the bathtub should be emptied and covered with a dust cover.