Preparation and maintenance of melting point tester before use

Preparation before use:

Place the heating container (beaker) containing the heat transfer liquid on the heating electric furnace, and then insert the required melting point thermometer into the fixing hole of the thermometer. Ensure that the bottom of the mercury bulb of the thermometer is at least 2.5 centimeters above the heating surface, and that the level of the heat transfer liquid is approximately at the immersion line of the thermometer. ‌1
Power on:

Turn on the power switch of the melting point tester, rotate the pressure regulating transformer clockwise to heat the heat transfer liquid, and then start the "mixing" switch to stir the mixer in the heat transfer liquid.
Confirm operation:

When the temperature of the heat transfer liquid rises to 10 ℃ below the lower limit of the melting point, rotate the pressure regulating transformer to increase the heating rate by 1.0-1.5 ℃ per minute (for melted and decomposed samples), while increasing the heating rate by 2.5-3.0 ℃ per minute. After reaching the expected melting temperature, cool the temperature. Repeat 2-3 times to control the heating rate, adjust the height of the thermometer so that the immersion line is just at the liquid level.
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Maintenance after use:

After using the melting point tester, turn off the power, use a mixer to adjust the voltage regulating transformer to the 0 scale, remove the thermometer, dry it with filter paper, and fill in the usage record.
In addition, there are some precautions and operational details that need to be noted:
Before conducting formal testing, preparations must be made before use, such as injecting silicone oil and replacing the oil bath tube. ‌2
Input the required starting temperature through the starting temperature dial, and the set starting temperature should be lower than the melting point of the substance being tested.
After preheating the instrument for 20 minutes, place the capillary tube containing the substance to be tested into the oil bath tube through the small hole in the insertion port.
Select the heating rate as needed, press the corresponding key, and there will be a bright indicator in the upper left corner, indicating that the instrument has entered the linear heating working state.
These steps and precautions ensure the correct and safe use of the melting point tester, thereby obtaining accurate melting point test results.