Attention point when purchasing constant temperature and humidity test chamber
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Constant temperature and humidity test chamber temperature part:
First, the temperature fluctuation: temperature fluctuation is a relatively easy to achieve parameters, the actual temperature fluctuations of most of the test chambers produced by all environmental testing equipment manufacturers can be controlled within ± 0.3 ° C.
2. Wind speed: According to the relevant standards, the wind speed in the temperature and humidity chamber should be less than 1.7m/s when conducting environmental tests. For the test itself, the wind speed is as small as possible. The wind speed is too high to accelerate the flow of the test piece and the flow inside the box. Heat exchange is unfavorable in the authenticity of the test. However, in order to ensure the uniformity of the working chamber of the constant temperature and humidity test chamber, it is necessary to have circulating air in the test chamber.
Third, the temperature field uniformity: In order to more accurately simulate the actual environmental conditions suffered by the product in nature, in the environmental test, it must be ensured that the periphery of the tested product is at the same temperature and environmental conditions, for which it must be in the test chamber. Temperature gradients and temperature fluctuations are limited. In the national military standard GJB150.1-86 military equipment environmental test method general provisions clearly stipulate "the temperature of the measurement system near the test sample should be within ± 2 ° C of the test temperature, the temperature of the work does not exceed 1 ° C / m or the total zui The value is 2.2 ° C (test sample does not work).
Fourth, the choice of cooling method: the refrigeration system needs to be cooled. The test chamber is available in both air-cooled and water-cooled versions.
Constant temperature and humidity test chamber humidity part:
Accuracy control of humidity: Most of the humidity measured in the environmental test chamber is dry and wet ball method, the manufacturing standard GB10586 of environmental test equipment, the relative humidity deviation should be ±23% RH. In order to meet the requirements of humidity control accuracy, the temperature control accuracy of the humidity test chamber is high, and the temperature fluctuation is generally less than ±0.2 °C. Otherwise it is difficult to meet the requirements of humidity control accuracy.