Views: 149 Author: Site Editor Publish Time: 2019-10-10 Origin: Site
The Correct Use Method of Thermal Shock Test Chamber
Environmental test equipment is a kind of precise and valuable equipment. Correct use and operation of thermal shock test chamber can not only provide accurate basis for inspectors, but also make environmental test equipment run normally for a long time and prolong its service life. So how to use the thermal shock test machine correctly?
1. In the environmental test, be familiar with the sample performance, test conditions, test procedures and test techniques of the required test, be familiar with the technical performance of the test equipment used, and have an understanding of the construction of the equipment, especially be familiar with the operation and performance of the controller. Also carefully read the operating manual of the test equipment, in order to avoid the abnormal operation of the test equipment caused by the operation error, resulting in damage to the test sample, the test data is incorrect.
2. Reasonably choose the test equipment. In order to ensure the normal operation of the test, the appropriate test equipment should be selected according to the different conditions of the test sample, such as thermal cycling test chamber. And a reasonable ratio should be maintained between the test sample and the effective volume of the test chamber. For the fever test samples, the volume should be no more than one tenth of the effective volume of the test chamber. For non-fever test samples, the volume should be no more than one-fifth of the effective volume of the test chamber. For example, when a 21-inch color TV is used for temperature storage test, a one-cubic-volume temperature impact test chamber can meet the requirements. When it is energized, it cannot meet the requirements. It should be replaced with a larger test chamber, because the TV has to radiate heat when it is working.
3. Place the test sample correctly. The position of the test sample should be more than 10cm away from the wall of the thermal shock test chamber, and multiple samples should be placed on the same plane as much as possible. The place where the sample is placed should not block the air outlet and the return air outlet,and a certain distance should be set aside for temperature and humidity sensors to ensure the correct test temperature.
4. For the environmental test required to add the medium in the test, it should be added correctly according to the test requirements. The temperature cycling chamber has certain requirements, the test chamber water resistivity should not be lower than 500 Ωm. The general tap water resistivity is 10-100 Ωm, the distilled water resistivity is 100--10000 Ωm, and the deionized water resistivity is 10,000-100000 ohms. Therefore, the test water should be distilled or deionized water, and it must be fresh. Because water and air contact, vulnerable to carbon dioxide and dust pollution, water can dissolve a variety of substances, after a long time, the resistivity will decline. There is now a pure water on the market that is economical and convenient, and its electrical resistivity is equivalent to distilled water.
5. Wet ball gauze for hot and cold impact test chambers has certain requirements. Not all gauze can be substituted, because the relative humidity reading is the difference between the temperature and humidity, which is strictly related to the local atmospheric pressure and wind speed. The wet bulb temperature indication is related to the amount of water inhaled by the gauze and the surface evaporation. These are directly related to the quality of gauze, so it rules that wet gauze must be woven for linen ldquo. Otherwise it is difficult to ensure the correctness of the wet bulb thermometer, that is, the correct humidity. In addition, the placement of wet ball gauze is also clearly stipulated. The 100mm gauze should be tightly wound around the sensor probe, and the probe should be immersed in the water cup by 25 mdash, so as to ensure the correctness of the device control and the humidity.
Environmental test equipment is a combined test apparatus that simulates one or more harsh environments in a laboratory using manual methods. As the indispensable test equipment, the proper use and maintenance of thermal shock test equipment is especially important.