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Focus on the two exposure methods of the ultraviolet aging test chamber
Focus on the two exposure methods of the ultraviolet aging test chamber
Core reminder: When using the UV test box for aging test, the ambient temperature of the test piece is a key exposure parameter. Generally, too high temperature will accelerate the whole process of polymer dissolution, and the allowable test temperature should depend on
When using a UV test box for aging test, the ambient temperature of the test piece is a key exposure parameter. Generally, too high temperature will accelerate the whole process of polymer dissolution. The allowable test temperature should be based on the tested raw materials and the aging performance evaluation method. set. The infrared induction of fluorescent ultraviolet germicidal lamp is less than that of xenon lamp and carbon arc lamp. The heating effect of the surface of the specimen is mostly produced by the thermal convection of warm air. Therefore, the temperature difference between the classroom blackboard thermometer, the black standard thermometer, the surface of the specimen and the gas in the exposure chamber is not large.
The following two exposure methods: Exposure methods 1 and 2 are respectively relative to the above-mentioned machinery and equipment â‘ and â‘¡. Customers can also choose other methods, but the exposure standard should be indicated in the experimental standard.
Exposure method 1
When the test piece has been exposed to light for a period of time, it is followed by a non-irradiation period (when the temperature changes greatly and condensation is produced on the test piece). According to relevant standards during the test period, if the circulatory system standard is not required, the following circulatory systems are strongly recommended:
Exposure to the black standard temperature of 60℃±3℃ for 4h or 8h, and then at the black standard temperature of 50℃±3℃ without irradiation for 4h.
Note: The embrittlement and dissolution of some polymers (such as PVC) is very sensitive to temperature. In this case, it is recommended to use an exposure temperature of less than 60℃ (such as 50℃) to simulate a colder climate.
When using the procedure of radiation exposure followed by condenser exposure, the allowable radiation or condenser exposure period is 2h to ensure that the standards for each exposure period are balanced.
Exposure method 2
The test piece continues to carry out the circulatory system experiment with radiation exposure and regular watering. Relevant standards during the trial period. If there is no requirement, the following experimental standards are strongly recommended:
Irradiate and expose for 5h under the black standard temperature of 50℃±3℃ and relative humidity (10±5)﹪. Then, irradiate and expose again at the black standard temperature of 20℃±3℃ and sprinkle water for 1h.
Note: â‘ : Make the exposed surface of the test piece dew and moisturize according to the moisture condenser in the machine and equipment. The moisture in the body is caused by the warming of the water in the vessel set directly below the specimen rack.
â‘¡: When the equipment does not conform to the exposure method 1, the method of showing the air humidity in the exposed room can be used, or the method of spraying the test piece with pure water or a solution that simulates the haze. For tap water, refer to GB/T 9344-88.
Explain the maintenance skills of the ultraviolet light aging test box
Core tips: 1. The shell of the digital display light incubator should be grounded reliably. 2. The sun exposure time can be programmed and manipulated independently by the "programmed timer". Please refer to "Program Control
1. The shell of the digital display light incubator should be grounded reliably.
2. The sun exposure time can be programmed and manipulated independently by the "programmed timer". Please refer to the instruction manual of "Programming Time Controller" for programming method.
3. In order to ensure reasonable heat pipe heat dissipation of the cooler, the distance between the cooler and the wall should exceed 100mm, the side of the shell should have a gap of 50mm, and the top of the shell should have at least 300mm of indoor space.
4. The digital display light incubator should be placed in a cool, dry, well-ventilated area, free from pyrogens, wind and sun. Stable placement to prevent vibration and noise.
5. When the digital display light incubator is in refrigeration work, it is not suitable to make the difference between the temperature in the cabinet and the working temperature exceed 25 degrees.
6. When the digital display light incubator is transported, repaired, and maintained, it should be protected from impact, shaking and vibration, and the steep slope is less than 45 degrees.
7. If the instrument is suddenly not working, please check whether the fuse tube (behind the box) is burned out and check the power supply system status.