One of the criteria for evaluating the performance of the high and low temperature box is uniformity, but most of the high and low temperature box manufacturers have shortcomings in uniformity control and cannot meet the needs of users for high precision, so today we will analyze the uniformity of the high and low temperature box The reasons for the poor performance, and how the professional high and low temperature box manufacturers control the uniformity.

The reason for the low uniformity of the high and low temperature box

The structure of the test box affects the temperature uniformity in the middle of the work to a large extent. Because the structure is difficult to be completely symmetrical, it has an adverse effect on the temperature uniformity. The structure has good left-right symmetry, and it is easy to achieve uniform temperature on the left and right, but the structure is asymmetrical on the top and bottom, and the front and back are completely different, which has an uneven effect on the temperature of the working space. Nevertheless, this single air duct structure is designed as Properly handled, practice has proved that the studio can be used from 0.1-300m3, and its temperature deviation can meet the standard requirements.

Due to the heat conduction of the box wall, heat loss such as heat leakage (high temperature box) or cold leakage (low temperature box) is generated. In order to compensate for the heat loss, there must be a temperature difference in the supply air. The supply air temperature of the high temperature box is higher than the working temperature in the box, and the low temperature The air supply temperature of the box is lower than the working temperature in the box. Due to the inevitable temperature difference of the supply air, temperature unevenness occurs in the work room.

Because the heat transfer coefficients of the six sides of the box wall are not equal, and some have local heat transfer such as threading holes, the temperature of the box wall is not uniform, so that the radiative convection heat transfer of the box wall is not uniform, which affects the uniformity of the temperature field.

The sealing of the box is not good, such as the door leaking air, which affects the uniform temperature field of the working space.

If the detection temperature deviation requires the test object to be placed in the studio, the air convection will be blocked when the test object is too large, or placed in an inappropriate manner or position, which will result in a large temperature deviation.

How to Control Equipment Uniformity

In terms of the precision control of the high and low temperature box, in order to precisely control the uniformity of the test box, the hot gas bypass method is adopted. The low-pressure side method ensures that the system always operates under a given small return air pressure. Coupled with the efficient control method, the overall operation of the equipment achieves high stability and high uniformity.