The power measurement method of the high and low temperature test chamber is divided into 5 points:
1. The environment of the test area:
The environment The test chamber with high and low Temperature can affect the conditions in the test chamber. The determination of the performance of the test chamber should be carried out under normal atmospheric conditions, and the following requirements should be considered: Environmental conditions to which it should not be exposed Direct sunlight, should not be exposed to electromagnetic interference, should be placed horizontally, it should be rotated in one place free from mechanical vibration and acoustic vibration interference and the test box manufacturer's recommendations for current and environmental conditions should be taken into account.
2. Temperature measurement system:
The uncertainty of the measurement results of the measurement system is determined by the calibration of the systemmt. In general, the sensor should be of the resistance type or a thermocouple type. The 50% response time of the sensor in the air should be between 10 and 40 seconds, and the response time of the whole system should be less than 40 seconds.
3. The test load of the high and low temperature test chamber:
We will have notes in all technical documents (the following technical indicators are all measured under no-load conditions) , if the test chamber is not can be completely empty, this should be recorded. Whether the measured samples in the box generate heat, weight, quantity, placement density and arrangement order affect it.
4. Installation of the temperature sensor:
The temperature measurement sensor is located in each corner of the test box and in the middle of the working space. At least 9 sensors should be placed in it. For high and low temperature test chambers over 2000L, the sensors should be directplaced in front of the center of each chamber wall (given the large space in the chamber, the sensors should be installed in the chamber to achieve accurate uniformity). . (at least 15 sensors) The structure of the measuring system should not influence the temperature distribution of the idle test chamber and should be able to record the temperature actually reached. The device must be independent of the chamber control.
5. Temperature performance measurement:
After the test chamber is stabilized, the actual temperature, temperature fluctuation and temperature gradient of the working space are confirmed by the measurement results of the measurement system, and should be taken as the uncertainty of the Temperature measurement system are considered.
Appendix: To determine the rate of temperature change, set the test chamber to the specified temperature, or set the test chamber to the specified temperature and monitor the time that the temperatureincreasing from the 10% temperature range temperature point to the 90% temperature point to stabilize the test chamber, set the test chamber to the specified temperature and monitor the time it takes for the temperature to drop from 90% of the temperature range to 10% of the point value) or a linear temperature rise and fall of 1-20 degrees/minute (the term in the device setting is “slope”) according to user needs.