In various experimental and production scenarios involving heat measurement, the accuracy of the calorimeter is crucial, and the calibration work is the core link to ensure its measurement accuracy. So, what exactly is the calibration used for the calorimeter? Here is a detailed analysis for you.

Correction substance: Benzoic acid is the core choice

The commonly used substance for calorimeter calibration is benzoic acid. Benzoic acid has the characteristics of stable combustion calorific value, high purity, easy access and complete combustion. Its standard combustion calorific value is known and accurate. During the calibration process of the calorimeter, the measurement system of the calorimeter can be calibrated by allowing the benzoic acid to be fully burned in the calorimeter, and the released heat can be used as a standard reference. Before use, it is necessary to ensure that the purity of benzoic acid is up to standard. Generally, the purity is not less than 99.9%. At the same time, it should be pressed into flakes to ensure sufficient combustion.

Calibration standards: follow national and industry standards

The calibration of the calorimeter must strictly follow the relevant national and industry standards. For example, our country has a special calibration specification for the calorimeter, which clearly stipulates the environmental conditions, operation procedures, data processing and other aspects of the calibration. The ambient temperature should be stable within a specific range, usually 15 ° C - 30 ° C, and the temperature fluctuation should not be too large; the humidity should also be controlled within a reasonable range to avoid affecting the correction results due to environmental factors. Only by strictly following the standard can the calibration be scientific and authoritative.

Correction steps: standardized operation to ensure accuracy

1. Instrument preparation: Install the components of the calorimeter in place first, check whether the instrument is in normal condition, and ensure that the oxygen bomb has good sealing and no air leakage. At the same time, preheat the instrument to achieve a stable working state.

2. Benzoic acid weighing: Use a high-precision balance to accurately weigh a certain quality of benzoic acid tablets, record the exact value, and control the error within a very small range.

3. Sampling and ignition: Put the weighed benzoic acid tablet into the oxygen bomb, connect the ignition wire, fill it with enough oxygen, and put the oxygen bomb into the inner cylinder of the calorimeter. Ignite according to the operation process of the instrument to fully burn the benzoic acid.

4. Data recording and calculation: The instrument automatically records data such as temperature changes during combustion, and calculates the calibration coefficient of the calorimeter based on the standard combustion calorific value of benzoic acid and the actual measurement data.

Mastering the calibration method of the calorimeter can not only ensure the accuracy of the measurement data, but also prolong the service life of the instrument. Strictly following the calibration materials, standards and procedures is the key to ensuring the stable operation of the calorimeter.