Ultraviolet weather resistance test chamber is mainly used to simulate the destruction of sunlight, humidity and temperature on the material; material aging includes fading, loss of light, strength reduction, cracking, flaking, powdering and oxidation. The sunlight, condensation, and humid environment conditions required by the customer for the test are fully achievable.

The ultraviolet weather resistance test chamber can reproduce the damage caused by sunlight, rain and dew. The equipment conducts the test by exposing the material to be tested in a controlled alternating cycle of sunlight and moisture while increasing the temperature. The equipment uses ultraviolet fluorescent lamps to simulate sunlight, and can also simulate the effect of moisture through condensation or spraying.

1. Humid condensation environment

The time when the outdoor materials are exposed to moisture can be as long as 12 hours per day. The research results show that the main reason for this outdoor humidity is dew, not rain. The UV accelerated weathering test machine simulates the effect of outdoor moisture through a series of unique condensation principles. In the condensation circulation circle of the equipment, there is a water storage tank at the bottom of the tank body, and it is heated to generate water vapor. Hot steam maintains the relative humidity in the test chamber at 100% and maintains a relatively high temperature. The design of the product ensures that the test specimen actually constitutes the side wall of the test chamber, so that the back of the specimen is exposed to the ambient air in the room. The cooling effect of indoor air causes the surface temperature of the test piece to drop to a level a few degrees below the steam temperature. The appearance of this temperature difference leads to the liquid water generated by condensation on the surface of the test piece during the entire condensation cycle. This condensation product is very stable pure distilled water. This pure water improves the reproducibility of the test while avoiding water stains.

For some applications, water spray can better simulate the environmental conditions of the end use. Water spraying is extremely useful in simulating mechanical erosion caused by drastic temperature changes and rain erosion. Roofing, automotive materials, and coatings used on metal buildings or structures often encounter sudden temperature changes. For example, in the hot summer, when heat builds up, it suddenly dissipates due to heavy rain. The consequences of this drastic temperature change are a challenge for many materials. The UV weathering test chamber / spray type is specially designed to reproduce this condition.

2. Simulate sunlight

The ultraviolet rays in sunlight are the main factors that cause the durability of most materials to be destroyed. We use ultraviolet lamps to simulate the short-wave ultraviolet portion of sunlight, which produces little visible or infrared spectral energy.

Although ultraviolet light (UV) accounts for only 5% of sunlight, it is the main lighting factor that causes the durability of outdoor products to decrease. This is because the influence of sunlight's photochemical reaction increases with decreasing wavelength. Therefore, when simulating the impact of sunlight on the physical properties of materials, there is no need to reproduce the entire sunlight spectrum. In most cases, you only need to simulate short-wave UV light.

The reason why the UV weather resistance test box uses UV lamps is that they are more stable than other lamps, and can better reproduce the test results. Using fluorescent UV lamps to simulate the effects of sunlight on physical properties, such as brightness reduction, cracking, and flaking, is the best method. There are several different UV lamps to choose from. Most of these UV lamps mainly produce ultraviolet light instead of visible light and infrared light. The main difference between lamps is the total UV energy they produce in their respective wavelength ranges. Different lamps will produce different test results. The actual exposure application environment can prompt which type of UV lamp should be used.

3. Temperature control

UV cycle

The first-level photochemical reaction is not sensitive to temperature changes. However, the speed of the subsequent secondary reaction is closely related to temperature changes. Generally speaking, as the temperature increases, the reaction speed will increase. Therefore, during the UV exposure test, temperature control is very important. It is more important to match the test temperature used in the accelerated test with the highest temperature encountered in the actual application of the material. The UV temperature setting in the device can be any point from 50 ° C to 80 ° C, depending on the light level and indoor ambient air temperature. The temperature adjustment of the equipment is accomplished through a series of systems such as air heaters, water heaters, etc. in the equipment through a controller with a microcomputer calculation function.

Moisture circulation

As the temperature increases, the destructive power of moisture on the material will increase dramatically. Therefore, in the process of wet exposure, temperature control is the most basic requirement. Furthermore, in order to produce an acceleration effect, it is required to maintain a high temperature environment during the wet exposure. The temperature setting of the condensation process in the equipment can be any point from 40 ° C to 60 ° C.

Heating system

a.U-shaped titanium alloy high-speed heating electric tube;

b. Temperature control and lighting are completely independent systems;

c. The temperature control output power is calculated by the microcomputer to achieve high-precision and high-efficiency power consumption benefits;

d. With anti-overtemperature function of heating system;

The temperature of the black aluminum plate is controlled and heated by the intelligent "Autonics" series temperature controller. The output power is calculated by the microcomputer and the PID is automatically set. Monitoring adopts standard Pt-100 blackboard temperature sensor;

The temperature of the water tank is also controlled by the "Autonics" temperature controller. The water tank is located in the lower part of the box and has an electric water heater. During the cycle test, there is a dark condensation process in the test section. It needs to generate saturated water vapor at a higher temperature in the cabinet. When the water vapor encounters a relatively cold sample surface, dew will condense on the sample surface.

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