Analysis of Temperature Tolerance and Relative Humidity of Constant Temperature and Humidity Tester

Constant temperature and humidity testing machine temperature tolerance

Among the numerous environmental test method standards, the test condition tolerance is an important technical indicator. It reflects the requirements of the environmental test on the control level of the equipment and reflects the normativeness of the environmental test. Therefore, it is of utmost importance to correctly understand the regulations concerning the tolerance of the test conditions on the relevant standards, thereby improving the reliability and scientificity of environmental test results.

The national standard GB2423.1 low temperature test method stipulates that the allowable temperature deviation range is ±3°C . Here, ±3°C does not mean the point or the time at that time, and the requirement for each point of the entire working space. Another problem that should also be pointed out is that the ±2°C temperature tolerance is the concept of allowable deviation. When the temperature gradient of the GJB150 military standard is 2.2°C maximum, the temperature field uniformity requirement is the relationship between the temperature of each point in a certain instant temperature field. . This temperature tolerance of ±2°C must not be regarded as the setting range of the nominal value. Example 60±2°C : 60°C is the nominal value at this time, ±2°C is the tolerance When setting the environmental condition parameter value, the temperature setting value can only be 60°C instead of 62°C , or 58°C. Due to the error in the drift adjustment of the control system and the inhomogeneity of the test chamber temperature field, the test temperature test result cannot be 60°C . The allowable deviation is but the range is not to exceed 62°C or not to fall below 58°C.

Measurement of Relative Humidity of Constant Temperature and Humidity Tester

Relative humidity is an important parameter in environmental tests. Measuring the relative humidity reasonably and accurately is of great significance for ensuring the environmental conditions. The so-called relative humidity was explained in detail in the previous chapters of the technical article “Air humidity in a constant temperature and humidity machine”.

Wet and dry balls for measuring relative humidity:

1) Select two sensors with the same model and the same characteristics. The axes of the two thermometers should be parallel. The distance between the sensors should not be less than 3 times the total diameter of the wet ball sensor ( including wet ball yarns )

2) The cup should preferably be covered with a lid and filled with distilled water. The distance between the surface of the cup and the bottom of the wet bulb sensor is 30mm .

3) High penetration of wet bulb water (70 to 80) mm .

4) Read out the indications of the dry and wet bulb thermometers respectively, and determine the relative humidity value at that temperature according to GB6999-86 .