As a commonly used heating equipment in laboratories and industrial production, the accuracy of the internal temperature of a blast drying oven is crucial for experimental results and product quality. However, due to various reasons, there may be deviations in the internal temperature of the blast drying oven. The following will elaborate on the calibration method for inaccurate temperature inside the blast drying oven:

1、 Preparation before calibration

1. Equipment inspection: Appearance inspection: Confirm that the drying oven is not damaged, the interior is clean and free of foreign objects, and the ventilation openings are not blocked. Sensor detection: Check if the temperature sensor is damaged or has poor contact, and replace it with a new sensor if necessary.

2. Tools and standard instruments: High precision calibration equipment (such as thermocouples, RTD thermometers) should be prepared to compare the actual temperature inside the measurement box. Additional tools such as timers and record sheets need to be considered for long-term monitoring of multiple temperature points.

2、 Temperature calibration steps

1. Set test temperature points: Select three or more temperature points that cover the working range (such as low temperature, medium temperature, and high temperature), such as 50 ℃, 100 ℃, and 150 ℃.

2. Place calibration sensors: evenly distribute the calibration temperature sensors in different positions inside the box (such as upper, middle, and lower layers) to ensure coverage of the hot air circulation path.

3. Operation and data collection: Start the drying oven and set the target temperature. After the temperature stabilizes, continue monitoring for at least 30 minutes and record the readings and time of each sensor. If the temperature deviation exceeds the allowable range (usually ± 2 ℃), parameter adjustment is required.

4. Adjust temperature controller parameters: Enter the internal parameter settings of the instrument and adjust the zero position (Pb) and full degree (PK) errors through the correction formula.

3、 System self-tuning optimization

When the temperature fluctuates greatly or conventional calibration cannot meet the accuracy, the system self-tuning function can be triggered:

1. Operation method: Long press the "Shift" button for 6 seconds to enter the self-tuning mode, select "ON" to start the process.

2. Precautions: During the self-tuning process, there may be significant temperature overshoot, so it is necessary to empty the sample box in advance.

3. Verification effect: After the self-tuning is completed, retest the temperature stability. If it still does not meet the standard, it is necessary to combine hardware inspection (such as heating element performance).

4、 Subsequent maintenance and validation

1. Regular re calibration: Repeat the above calibration steps every quarter or six months, especially for frequently used equipment, shorten the cycle.

2. Record archiving: Save the data report and adjustment records of each calibration to form a traceable quality management system.

The calibration method for inaccurate internal temperature of a blast drying oven involves multiple aspects. By following the correct calibration steps and precautions, the temperature control system of the drying oven can be ensured to be accurate and reliable, thereby meeting the needs of experiments or production.