For the temperature and humidity test chamber, temperature uniformity is the core basis for assessing the eligibility of the equipment. The national standard of the constant temperature and humidity test chamber clearly specifies that the temperature uniformity is less than or equal to ± 2 °C. However, due to various factors such as unreasonable equipment design and sample placement, the uniformity deviation may be excessive. What aspects of the uniformity of the constant temperature and humidity test chamber?
When testing, the test sample volume should not be too large. The placement of the test sample is not satisfactory, and the air convection in the box is blocked. For example, placing the sample in the air duct mouth affects the circulation of the wind.
Because the heat transfer coefficient of the front and rear left and right sides of the box wall in the test chamber is different, some test lead holes cause local heat dissipation and heat transfer, so that the temperature of the box is not uniform, so that the wall convection heat transfer is also Uneven, affecting temperature uniformity.
It should be noted that when selecting the constant temperature and humidity test chamber, special attention should be paid to the structural design of the equipment. It is difficult to achieve a uniform symmetrical structure in the design of the internal structure and space of the test box, and the asymmetric structure will inevitably lead to the internal temperature. The uniformity produces a deviation. The difference in structural design causes the temperature of the inner wall of the test chamber to be uneven, which in turn affects the thermal convection in the working chamber, resulting in deviations in the internal temperature uniformity. In addition, the sealing of the test chamber door and the cabinet was observed. Poor sealing will inevitably lead to uniformity deviation.
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