Why the environmental chamber need the wet bulb gauze during humidity test ? Why the humidity sensor inside the test room need cover the wet bulb gauze ? Users who have used the environmental test chamber know that when doing humidity test in an environmental chamber, We need to use the wet bulb gauze to cover the humidity sensor. Some users are curious and don’t want to use the wet bulb gauze. But it is the wrong way absolutely !
You may need some humidity test with an environmental chamber. After a long time humidity test, The wet bulb gauze will lose the lifetime and need to do replace work. Not only the environmental chamber from Wewon Environmental Chambers Co., Ltd. According to the current industry constant environmental chamber test standards, Most of the humidity measurements are based on the method of comparing the temperature of the dry and wet bulb gauze.
At a fixed wind speed, The wet bulb gauze’s temperature difference and humidity value are constant. This difference is generated by humidity sensor cover with the wet bulb gauze. Due to the principle of evaporation and endothermic, the humidity sensor’s temperature drop
down and make the result happen. So be sure to wrap the wet bulb gauze on the humidity sensor and make sure the wet bulb gauze absorbs water. Otherwise, the humidity value from the controller system will not be displayed accurately.
Please check the temperature of your test room where the climatic chamber parked. The environment temperature without air flow which will affect the machine’s work performance. When the test room temp increased and higher, The climaitc chamber will take more power to make the temperature and humidity average work ! This will affect the temp and humidty’s fluctuate.
After a few month testing work, Please try to replace a new wet bulb gauze. Because the long time wet bulb gauze be used, It may insensitive because many time hot air temperature roast. Below is a video which will teach you how to replace a new wet bulb gauze. What we can say is, The temp and humidity uniform average is a complex adjust work. It takes time to find it and judge where can make it better way, So we need time to judge and improve it step by step. Thank you.
There are many reasons which will occur the temperature and humidity test value difference. We suggest you display the related photos when your engineer do the temp and humidity calibration work. Then we can check it and estimate your situation if they are in right way ! Furthermore, Wet bulb gauze has a variety of different name around the world，For example: wet-bulb wick, wet bulb lab wick, hygrometer wet bulb wicks, wet bulb thermometer wick.
https://youtu.be/KWrAONGYRhM
Basically, Environmental chamber from Wewon Tech has the features: Temperature fluctuation tolerance: +-1.5C, Humidity tolerance with +-2.5%RH which will meet the international standard. Please make sure your calibration work from 40 minutes later when you power on your environmental test chamber. Because the first 30 minutes is unstable on temperature and humidity performance work.
If you want a more uniform average temperature and humidity, Please try to use hand to adjust the inner metal window-shades. It can be moved up and down, left and right. You can use your hand to adjust the coming air directions and flow rate which is helpful for temp uniform adjust. If you don’t know where is the window-shades, Please email us for checking purpose !
Humidity Measurement Requirements In An Environmental Chamber｜Humidity Test Definition and Explanation In An Environmental Chamber
The environmental chamber is mainly used to accurately simulate the complex natural environment of low temperature, high temperature, high temperature and high humidity, low temperature and low humidity, etc. It is used to detect the performance change of the material in various environments and the heat, cold, dry and humidity resistance of the sample. The environmental chamber is suitable for the quality inspection of electrical, communication, instrument, vehicle, plastic products, chemistry, building materials, medical, aerospace and other test samples.
Of course, in the actual use of the environmental test chamber, there will inevitably be some errors/ difference in the measurement of humidity, so what are the requirements for the humidity measurement of the environmental chamber ?
The environmental test chamber according to the relevant standards for the humidity deviation of the humidity test equipment, in the temperature range of +25 ° C ~ +65 ° C, when the humidity is greater than or equal to 75% RH, the humidity deviation ± 3% RH. When the humidity test is less than 75%, the humidity deviation is ±5% RH. Of course, there are some special and relatively few test requirements, such as temperature 85 ° C, humidity 85% RH,｜temperature 90 ° C, humidity 95% RH and so on.
According to the requirements of the metric value transfer system table, the first-order humidity standard with a tolerance of ±1% RH, the second-level humidity standard with a tolerance of ±2% RH, and the tolerance of the second-level humidity standard of ±(2~7)%RH humidity work measuring instrument. This requires the humidity sensor to measure the humidity conditions with humidity deviation ±3%RH, Measurement error should be less than ±1.5%RH
Why The Environmental Chamber Can Not Do The Tumidity Test Below +20 ℃ And Above +85 ℃ ?｜+20 ℃ ~ +85 ℃ with Humidity Test
We know that the environmental chamber can do humidity test, and this humidity test can not be done at any temperature point. Humidity and temperature supplement each other. The following is the humidity reference chart of standard model from Wewon Environmental Chambers Co., Ltd.
Standard size environmental chamber do humidity test corresponds to the range of temperature is +20 ℃ ~ +85 ℃, It is a relative humidity, That is to say, the humidity that can only be generated in the corresponding temperature range. This range basically meets the simulation environment of all kinds of standards and test products. If you need to be humidity at a higher or lower temperature, you can customize it according to the actual situation.
The maximum humidity range for a constant environmental test chamber is 5 ° C to 95 ° C. If you need more severe high temperature and high humidity, you can choose the dehumidifier unit, which can display or control the humidity in the range of 105° C to 143° C. According to customer requirements for low temperature and low humidity or high humidity requirements, the cost will be more expensive, such as low temperature and low humidity often need to use dehumidifier and non-standard custom accessories, but also need special technical engineers to create good quality, stable performance of the environmental chamber.