The condition test standards for high, low temperature, and low pressure test chambers cover multiple aspects such as temperature range, pressure range, test type and parameters, test process and steps, equipment performance requirements, safety requirements, etc., as follows:
1、 Temperature range
High temperature test: The usual range is+40 ℃ to+200 ℃, and the specific temperature is determined according to the product characteristics and testing requirements. For example, some standards stipulate a high temperature working test temperature of+55 ℃ and a high temperature storage test temperature of+65 ℃.
Low temperature test: The usual range is -70 ℃ to 0 ℃, and the specific temperature is also determined based on product characteristics and testing requirements. For example, some standards stipulate that the low-temperature working test temperature is 0 ℃ or -20 ℃, and the low-temperature storage test temperature is -20 ℃.
2、 Pressure range
The pressure range for low-pressure testing usually ranges from atmospheric pressure (about 101.3kPa) to 1kPa to 100kPa, and the specific pressure value is determined based on the simulated altitude and product usage environment. For example, simulating a pressure of approximately 54kPa at an altitude of 5000 meters.
3、 Test type and parameters
Simple low-pressure test: Maintain a specific pressure for a period of time to observe changes in product performance. The allowable difference in air pressure is usually ± 5% or ± 0.1kPa (whichever is greater).
Low pressure temperature comprehensive test: Combining low pressure and temperature changes for testing, simulating temperature environments at different altitudes. For example, first cool down to -55 ℃ and maintain it for 4 hours, then heat up to -40 ℃ and turn on the power to work, and then lower the pressure to simulate an altitude of 7000 meters (41.06 kPa) and maintain it for 30 minutes.
Low pressure temperature humidity comprehensive test: On the basis of low pressure and temperature changes, humidity control is added to simulate more complex environmental conditions. For example, maintain a temperature of 32 ℃ and a relative humidity of 95% for 30 minutes.
4、 Experimental process and steps
Preprocessing: Conduct initial testing on the test sample under normal atmospheric conditions in the laboratory.
Conditional test: Place the test sample into the test chamber and conduct the test according to the set temperature, air pressure, and humidity parameters. During the experiment, it is necessary to regularly observe the status of the samples and record relevant data.
Recovery testing: After the experiment is completed, the test sample is restored under normal environmental conditions and then subjected to final testing.
5、 Equipment performance requirements
Temperature control: The test chamber should be able to accurately achieve and maintain the set high and low temperature range, with temperature fluctuations typically not exceeding ± 1 ℃ or ± 2 ℃, determined according to standard requirements.
Air pressure control: The test chamber should be able to reduce the air pressure inside the chamber to the set value within the specified time and maintain it stably. The accuracy of air pressure control usually reaches ± 2kPa (within the range of atmospheric pressure to 40kPa).
Uniformity: The temperature and air pressure inside the test chamber should be evenly distributed to avoid local overheating or overcooling, as well as uneven air pressure.
6、 Safety requirements
Overtemperature protection: The test chamber should have an overtemperature protection function, which automatically cuts off the heating power when the temperature exceeds the set value.
Overvoltage protection: The test chamber should have an overvoltage protection function, which automatically stops pumping or exhausting when the air pressure exceeds the set value.
Leakage protection: The test box should have leakage protection function to ensure the safety of operators.