In the calorific value measurement experiment, the ignition of the calorimeter is a crucial link. Whether the ignition is successful and standardized directly affects the accuracy of the experimental results. The following is a detailed introduction to the ignition method in the calorimeter, which is simple and easy to understand.

Preparations before ignition

First, make sure that the calorimeter is in normal working condition, check whether the components of the instrument are firmly connected, and whether the power supply and wiring are damaged. At the same time, prepare the ignition wire, usually platinum wire or nickel-chrome wire, cut it into a suitable length, fix one end on the electrode, and connect the ignition cotton at the other end. Oxygen is also required to ensure that the pressure of the oxygen cylinder is sufficient, and the connection pipeline is free of leakage, providing sufficient conditions for ignition to support combustion.

The specific steps of the ignition operation

The first step is to put the sample to be tested into the crucible, place the crucible smoothly on the bracket of the oxygen bomb, and then install the electrodes connected to the ignition wire in place to ensure that the ignition wire is in full contact with the sample, and the ignition cotton is wrapped around the sample.

The second step is to close the oxygen bomb cover, slowly open the oxygen cylinder valve, and fill the oxygen bomb with oxygen. The oxygenation pressure is generally controlled at 2.8-3 MPa, and the oxygenation time is maintained for about 30 seconds to fully fill the oxygen bomb.

The third step is to put the oxygen bomb into the inner bucket of the calorimeter, connect the ignition circuit, and after confirming that the circuit is connected correctly, start the ignition button. At this time, the instrument will heat the ignition wire through current, ignite the ignition cotton, and then ignite the sample.

Inspection matters after ignition

After the ignition is completed, observe the ignition status displayed by the instrument. If the ignition is successful, the instrument will enter the experimental process normally. If the ignition fails, turn off the power immediately. After the oxygen bomb cools down, take out the oxygen bomb, check whether the ignition wire is broken, whether the ignition cotton is damp, check the cause of the failure, and resume the ignition operation.

By mastering the above calorimeter ignition methods and following the steps strictly, the ignition can be successfully completed, laying the foundation for the accurate measurement of calorific value in the experiment.