How to calibrate Vacuum oven?

Vacuum Drying Ovens play an important role in the laboratory, and their accuracy is directly related to the reliability of experimental results. Therefore, calibrating the vacuum Drying Oven is one of the important steps to ensure its proper operation and accuracy. Here's how to calibrate the temperature and vacuum pressure indicators of a vacuum Drying Oven.

1. Calibration of temperature indicators

1. Arrangement of test points

When calibrating the temperature of a vacuum Drying Oven, the first step is to select a test point. In general, the working space volume of the vacuum chamber is less than 0.4 m³, so the middle level of the workspace can be selected as the test plane. The test point should be no less than 1/10 of the length of each side of the wall in the studio to ensure the accuracy and reliability of temperature measurement.

2. Measurement process

• Place the temperature sensor at the test point location and wait for the temperature to stabilize.

• The temperature indication of the vacuum Drying Oven and standard to be calibrated is recorded.

• According to the calculation method in the calibration specification, the corresponding values of temperature deviation, temperature uniformity and temperature fluctuation are calculated.

3. Precautions

When performing temperature calibration, you need to pay attention to the following:

• The temperature measurement is carried out in a non-vacuum, not in a vacuum. Therefore, the sensor used for temperature measurement should be a "wired" temperature sensor.

• Since the vacuum Drying Oven needs to be closed during the experiment, it is not possible to measure the temperature under vacuum. Therefore, the temperature calibration is carried out under atmospheric pressure conditions.

• The temperature measurement method should meet the requirements of the national standard to ensure the accuracy and reliability of the calibration results.

2. Calibration of vacuum pressure value index

1. Preparation of the measuring device

• A standard vacuum gauge is used as a benchmark for calibration.

• The standard vacuum gauge is connected into the vacuum containment system of the vacuum Drying Oven, ensuring a closed loop.

2. Measurement process

• Start the Vacuum Pump to make the vacuum level of the vacuum box close to -0.1MPa.

• After the vacuum level is stabilized, record the pressure indication value of the standard vacuum gauge and the vacuum gauge equipped with the vacuum box.

• Slowly release the vent valve of the vacuum chamber so that it deflates slowly and evenly.

• When the pressure indication value of the vacuum gauge equipped with the vacuum box reaches -0.08MPa, -0.06MPa, -0.04MPa and -0.02MPa respectively, the air release valve is closed and the pressure indication value after the indication is stable is recorded.

• Compare the differences in these indications as vacuum deviations for each test point.

Calibrating a vacuum Drying Oven is an important step in ensuring its proper operation and accuracy. Through the implementation of the above steps, the performance of the vacuum Drying Oven can be effectively verified and maintained, ensuring that it provides an accurate and reliable environment during the experiment.