Why does the constant temperature and humidity test box have large temperature deviations?

Constant temperature and humidity test box is also called constant temperature and humidity testing machine, constant temperature machine, etc.; it is used to test the performance of materials in different environments and the materials' heat resistance, cold resistance, dry resistance, and humidity resistance. It has a wide range of applications. When using the constant temperature and humidity test box, if you encounter the problem of large temperature deviation in the constant temperature and humidity test box, what causes it?

1. The structure of the constant temperature and humidity test chamber greatly affects the uniformity of the working temperature, and the structure is difficult to be completely symmetrical, which is not conducive to uniform temperature. Commonly used low temperature test box or constant temperature and humidity test box structure. The door is at the front, and the air-conditioning room is at the back of the test chamber, and the air is returned through the supply air. Obviously, this structure has good left-to-right symmetry and can achieve a uniform temperature on the left and right, but the structure is asymmetric from top to bottom, and the front and back are completely different, which has an uneven effect on the temperature of the working space. Nevertheless, if properly designed, practice has proved that the studio can be used between 0.1-300 mm, and its temperature deviation can meet the standard requirements.

2. The six sides of the box wall have different heat transfer coefficients, and there are local heat transfers such as threaded holes. The temperature of the box wall is uneven, and the convective heat transfer of the box wall is uneven, which affects the uniform temperature field.

3. Due to the heat conduction of the box wall, heat leakage (high temperature test box) and cold leakage (low temperature test box) and other heat losses occur. In order to compensate for the heat loss, there must be a supply air temperature difference. The supply air temperature of the high temperature box is higher than the work inside the box. Temperature, the supply air temperature of the low temperature box is lower than the working temperature inside the box. The inevitable supply air temperature difference makes the temperature in the working room uneven.