Preparation before use of calorimeter

Before using the calorimeter, it is necessary to ensure that the instrument is placed smoothly to avoid shaking affecting the measurement accuracy. At the same time, check whether the connection of all parts of the instrument is stable and whether the power supply is normally connected. Conduct a comprehensive inspection of the oxygen bomb of the calorimeter to check whether the oxygen bomb is well sealed and leaks. If any problems are found, it needs to be repaired or replaced in time. In addition, prepare the sample to be tested. The sample should be uniform and representative. It should be weighed according to the specified quality requirements, generally accurate to 0.1mg.

Sample loading operation

Put the weighed sample carefully into the crucible of the oxygen bomb to avoid spilling the sample. Next, install the ignition wire. The ignition wire should be in full contact with the sample, but not with the crucible wall to prevent short circuit. Then, add an appropriate amount of distilled water to the oxygen bomb, usually about 10mL, to ensure that the heat generated by the combustion of the sample can be fully transferred to the water. Finally, tighten the lid of the oxygen bomb to ensure a tight seal to prevent oxygen leakage.

Instrument parameter setting

Turn on the power supply of the calorimeter, enter the operation interface, and set the appropriate parameters according to the nature and requirements of the sample to be tested, such as ignition temperature, stirring speed, etc. Generally speaking, the ignition temperature is set according to the ignition point of the sample, and the stirring speed should ensure that the water can be heated evenly. After the parameter setting is completed, the instrument calibration is carried out to ensure the accuracy of the measurement data. The calibration process can be carried out according to the instrument manual, and the standard material is usually used for calibration.

Start the measurement process

Put the oxygen bomb filled with the sample into the measurement chamber of the calorimeter and close the measurement chamber door. Start the measurement program, the calorimeter will automatically start oxygenation, so that the oxygen bomb is filled with enough pressure of oxygen, the general oxygenation pressure is 2.8 - 3.0MPa. After the oxygenation is completed, the instrument automatically ignites, the sample starts to burn, and the stirrer starts to work, so that the water temperature rises evenly. During the whole measurement process, the instrument will monitor the temperature change in real time and record the data.

Data reading and processing

When the sample has burned completely and the temperature change has stabilized, the calorimeter will automatically stop the measurement and display the measurement results. When reading the data, carefully check the values to ensure the accuracy of the data. For the measured data, necessary processing needs to be carried out, such as deducting the heat of the ignition wire, considering the heat capacity of the instrument and other factors, and finally obtain an accurate sample heat output. If the measurement results deviate greatly, it is necessary to check whether there is a problem in the operation process and re-measure.

Post-use maintenance work

After the measurement, turn off the power of the calorimeter, take out the oxygen bomb, open the lid of the oxygen bomb, pour out the remaining water, and clean the residue inside the crucible and oxygen bomb. Wipe the surface of the instrument with a clean cloth to keep the instrument clean. Regular maintenance of the calorimeter, such as checking the working condition of the sensor, agitator and other components of the instrument, to ensure that the instrument is always in good operating condition.