Constant temperature and humidity tester temperature tolerance

Among the many environmental test method standards, test condition tolerance is an important technical index, which reflects the environmental test requirements for equipment control level, and reflects the normative nature of environmental tests. Therefore, it is of utmost importance to correctly understand the requirements of the standards for tolerances of test conditions, thereby improving the reliability and scientificity of environmental test results.

The GB2423.1 low temperature test method specifies a temperature tolerance range of ±3 °C, where ±3 °C does not refer to that point or at that time, for each point of the entire workspace. Another problem that should be pointed out is that the temperature tolerance of ±2 °C is the concept of allowable deviation. When the GJB150 military standard temperature gradient is 2.2 °C maximum, the temperature field uniformity requirement is the relationship between the temperature of each temperature field at a certain instant. . The temperature tolerance of ±2 °C should never be regarded as the setting range of the nominal value. Example 60±2°C: At this time, 60°C is the nominal value, and ±2°C is the tolerance. When setting the environmental condition parameter value, the temperature setting value can only be 60°C, but not 62°C, or 58°C. Due to the error in the drift adjustment of the control system and the non-uniformity of the temperature field of the test chamber, the measured result of the test temperature may not be 60 ° C, the allowable deviation but the range is not more than 62 ° C or not lower than 58 ° C

Measurement of relative humidity of constant temperature and humidity tester

Relative humidity is an important parameter in environmental testing. Reasonable and accurate measurement of relative humidity is of great significance for ensuring environmental conditions. The so-called relative humidity, we have a detailed interpretation of the technical article "The humidity of the constant temperature and humidity machine" in the previous chapters, not to elaborate here.

Dry and wet bulbs measure relative humidity:

1) Select two sensors with the same model and the same characteristics. The axis of the two thermometers should be parallel, and the distance between the sensors should be no less than 3 times the total diameter of the wet bulb sensor.

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

3) The penetration of wet bulb water is high mm.

4) Read the indication values ​​of the dry and wet bulb thermometers separately, and find the relative humidity value at this temperature according to GB6999-86.