In the xenon arc radiation test, the use of high-purity water is required to prevent the formation of deposits on the surface of the test plate, so the operating cost is higher.
UV lamp irradiation test
The ultraviolet lamp irradiation aging test uses fluorescent ultraviolet lamps to simulate the destructive effect of sunlight on durable materials. This is different from the xenon arc lamp mentioned above. The fluorescent ultraviolet lamp is similar in electric principle to the ordinary cold-light fluorescent lamp for lighting, but it can generate more ultraviolet light than visible light or infrared light.
For different exposure applications, there are different types of lamps with different spectrums to choose from. The UVA-340 lamp can simulate sunlight well in the main short-wavelength ultraviolet spectrum range. The spectral energy distribution (SPD) of the UVA-340 lamp is very similar to the spectrogram from 360nm in the solar spectrum. The UV-B lamp is also commonly used for accelerated artificial weathering test. It destroys materials faster than UV-A lamps, but its shorter wavelength energy output than 360nm will deviate from the actual test results for many materials.
Irradiance (light intensity) control is necessary to obtain accurate and reproducible results. Most ultraviolet aging test equipment is equipped with an irradiance control system. These precise irradiance control systems enable users to select irradiance measurements when conducting experiments. Through the feedback control system, the irradiance can be continuously and automatically monitored and accurately controlled. The control system automatically compensates for the lack of illumination due to lamp aging or other reasons by adjusting the power of the lamp.
Fluorescent ultraviolet light simplifies the control of irradiance due to its inherent spectral stability. All light sources will weaken over time. But fluorescent lamps are different from other types of lamps in that their spectral energy distribution does not change with time. This feature improves the reproducibility of the test results and is therefore a major advantage.
Tests have shown that there is no significant difference in output power between a lamp using 2h and a lamp using 5600h in an aging test system equipped with irradiance control. The irradiance control device can maintain a constant light intensity. In addition, their spectral energy distribution is also unchanged, which is very different from xenon arc lamps.
One of the main advantages of using the purple lamp aging test is that it can simulate the destruction effect of the outdoor humidity environment that is more realistic. When the material is placed outdoors, according to statistics, it is frequently exposed to moisture for at least 12 hours a day. Because this damping effect is mostly in the form of condensation, a special condensation principle is used to simulate outdoor humidity in the accelerated artificial weathering test.
During such a condensation cycle, the water tank at the bottom of the test chamber is heated to generate steam. Hot steam keeps the environment of the test chamber at 100% relative humidity at high temperatures. When designing the test box, the test board should actually constitute the side wall of the test box. In this way, the back of the test panel is exposed to room air at room temperature. The cooling effect of the indoor air makes the temperature of the surface of the test panel lower than the steam temperature by a few degrees. The temperature difference of several degrees can make the water continuously drop to the tested surface during the condensation cycle.
The condensate produced in this way is pure distilled water with stable properties. This kind of water can improve the reproducibility of the experimental results, eliminate the problem of water sediment pollution and simplify the installation and operation of the test equipment.
Because the material is generally exposed to moisture for a long period of time, a typical circulating condensation system requires at least 4 hours of test time. The condensation process is carried out under heating conditions (50 ℃), which will greatly accelerate the rate of moisture damage to the material. Long-term, condensing cycles under heating conditions are more effective than other methods such as water spraying, dipping, and other high-humidity environments to reproduce the phenomenon of damaging materials in a humid environment.
French Brush set for Nail Paint Art , French Nail Brush Set ,Nail Brush set
SAMINA FORAM (SHENZHEN) CO., LIMITED. , https://www.saminamakeuptools.com