The calibration items and calibration methods for the ventilation aging test chamber are as follows:
First, the calibration project: the total number of air replacements in the box, temperature deviation, temperature uniformity, temperature fluctuation.
Second, the calibration method
1, the choice of calibration temperature point
Generally, the lower limit, upper limit and intermediate point of the range of use of the ventilation type aging test chamber should be selected, and the common temperature points can be selected according to the user's needs, and calibration is performed at each temperature point.
2, the determination of the number of ventilation
1 power consumption of the test box in the sealed state
Close all vents of the ventilated aging test chamber, seal the door joints, inlet and outlet vents, thermometer sockets, and parts that may cause air circulation between the inside and outside of the box. Place the standard thermometer at the geometric center of the box to observe the temperature inside the box and adjust the temperature of the chamber to ±2 °C without deviating from the test temperature. After the temperature in the box was stable, the temperature was kept at 1 h. The standard electric energy meter is used to measure the power consumption of the test chamber heater in the sealed state for 0.5h or more, and is converted into the average power P1. The start and end of the test should be at the corresponding point of the heating cycle "on-off".
2 power consumption of the test box under the open state
Remove the sealing tape and adjust the position of the inlet and outlet holes for 1 h. The power consumption of the test box heater in the unsealed state was measured in the same manner and converted into an average power P2.
3 boxes outside the ambient temperature
About 2m away from the test chamber, approximately horizontal position with the bottom of the test box, and at least 0.6m away from any physical object, the difference between the temperature inside the box and the ambient temperature is the same in the two conditions of the test chamber, the error should be Less than 0.2 °C.
If the number of air changes in the test chamber calculated after the measurement does not meet the test conditions, the position of the inlet and outlet holes can be readjusted and re-measured as described above.
3, temperature deviation, temperature uniformity, temperature fluctuation measurement
1 test point location
The position of the test point shall be placed on the three calibration surfaces of the working space in the equipment working room. The working space is also called the measured space. It is located near the center of the ventilation aging test chamber, and its interface is parallel to the space inside the box. Not less than 150mm, the length and width are generally (200 ~ 250) mm, and the geometric center point should be 25mm without the temperature of the test chamber.
2 number of test points
The test points are generally nine, one test point is the center point of the measured space, and the other eight test points are respectively at the eight vertices of the measured space.
3 temperature calibration
Dispose the sensor as required, set the temperature controller of the test box to the required nominal temperature, and make the equipment work normally. When the temperature of the test chamber does not deviate from the test requirement temperature by ±2 °C and stabilize, the measurement is started, and all tests are recorded every 2 minutes. The temperature of the point was once, and 15 times were tested in 30 minutes.
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