Common faults and treatment methods of high low temperature shock test chamber?
Zhongzhi thermal shock chamber adopts a novel appearance design, and the chamber structure, refrigeration system and control technology have independent intellectual property rights. The product is energy-saving, safe, reliable and runs smoothly. It can be customized according to customer needs. It is suitable for ships, electricians High and low temperature impact test and storage and test under high or low temperature environment of electronic products and parts. The whole chamber is divided into upper, middle and lower zones, which are respectively high-temperature zone, test zone and low-temperature zone. It adopts a unique heat cut-off structure and heat and cold storage effect. During the test, the object to be tested is completely static, and the cold and hot air circuit switching mode is applied. During the impact test, the air valves in the high-temperature zone and low-temperature zone are automatically opened, so as to achieve the impact test of high and low temperature.
Common faults and treatment methods of high low temperature shock test chamber
1. When the temperature of the test chamber cannot reach the test temperature value, check whether there is a problem with the electrical control system.
2. When the temperature of the test chamber rises very slowly, carefully check whether there is a problem with the air circulation system of the chamber.
3. During the damp heat test, if the low temperature cannot reach the test index, the temperature change shall be observed first. If the temperature drops very slowly, it is necessary to consider whether the studio has been dried before the low temperature test.
4. Poor ambient temperature will cause machine failure, so the temperature must be 5-28 ℃ and the humidity must be about 95% during the test.
5. If there is a big difference between the actual humidity and the target humidity during the damp heat test, first check whether the humidification system works, and then check whether there is a certain amount of water in the water supply system of the humidification system and whether the water level control is normal. If everything is normal, check the electric control system and ask the maintenance personnel to repair it.
The ambient temperature of three box high and low temperature impact test chamber is particularly important to its working efficiency. The refrigeration process is an endothermic process. If the ambient temperature is too high, it will undoubtedly increase the working load of the compressor and greatly reduce its working efficiency.
How to define rapid temperature change?
The temperature change test with temperature change rate ≥ 3 ℃ / min is called rapid temperature change test. The temperature change rate is generally 3 ℃ / min, 4 ℃ / min, 5 ℃ / min, 7 ℃ / min, 10 ℃ / min, 15 ℃ / min, 20 ℃ / min and 25 ℃ / min.
This test is applicable to components, equipment or other products. Simulate the change with temperature during live working for the product, such as rapidly changing the ambient temperature when the system / component is working. If the system / component is at the hot soak temperature (e.g. the system / component installed on the engine), the additional transient temperature peak in the high temperature stage shall ensure the basic function of the product during this period. In order to prevent the electrothermal diffusion in the system / component from restraining the system / component from reaching the effect of low temperature, the product is closed in the cooling stage. The failure mode is electrical failure caused by temperature change. Temperature cycle effect: loss of electrical function, deterioration of lubricant and loss of lubrication, solder joint cracking, PCB delamination, loss of mechanical strength and plastic deformation of structure, rupture of glass and optical products, solder joint tin cracking, degradation of part characteristics, fracture, relaxation of moving parts, shrinkage and expansion of materials, failure of air tightness and insulation protection
Reference standard: GB /T 2423 34; IEC60068-2-38; GJB150.5
Safety knowledge of high low temperature test chamber?
1. When installing the test box, the shell of the box must be grounded. If the test box is not grounded, there will be a risk of electric shock in case of electric leakage;
2. Do not run the equipment before the equipment is installed, and ensure that the installation can be pulled aside before the test;
3. If the heating sample is placed in the box, please use the external power supply for the sample control power supply, and do not directly use the local power supply;
4. The operation of the box will produce dangerous current. Non professionals are not allowed to open the cover plate of the electric control cabinet;
5. If the high and low temperature test chamber is not equipped with humidification function, pay attention to the differences in use and requirements when reading the instructions;
6. When the machine is running, all kinds of motors and fans are started according to the instructions under the control of the controller. Never touch the components that are temporarily in a static state with your hands to prevent the components from starting suddenly and causing personal injury. When you really need to work close to the rotating components, please cut off the main power switch and ensure that the protective device is intact
7. It is forbidden to move the test chamber when there is a sample in it, otherwise the sample may reverse or fall;
8. Before use, ensure that the high and low temperature test chamber has been fixed, that is, the casters are off the ground and adjust the feet to the ground, otherwise the test chamber will move accidentally under external force
What is the difference between cold and hot shock test chamber and rapid temperature change test chamber?
1. According to the particularity of the sample to be tested, the cold and hot impact tester is divided into two zones dynamic impact and three zones static impact. It can be used for cold and hot impact, or for separate high temperature or low temperature use. The test temperature of the product can be changed from high temperature 150 ℃ to - 40 ℃ or lower.
(a.) the two zones type cold and hot shock box adopts the upper and lower boxes (high temperature in the upper zone and low temperature in the lower zone). The middle is the blue lifting, which is the place where the sample can be placed. The blue lifting is switched up and down through the transmission device, and the fast conversion is carried out in the high and low temperature chamber, so as to realize the temperature shock
(b). Three zones type cold and hot shock box (high temperature in the upper zone, low temperature in the lower zone and sample area in the middle). The measured sample is placed in the sample area. The high temperature zone and low temperature zone store energy according to the set temperature, and the low temperature or high temperature is sent to the sample area through the flapper to form a temperature shock
2. The rapid temperature change test chamber is that the temperature rises or falls according to the change speed of one change. The temperature change time is different and the temperature change rate is different. It can be divided into linear and non-linear. To sum up, the difference between the two mainly lies in one temperature change rate. The cold and hot shock is the instantaneous heating and cooling, while the rapid temperature change is to increase and decrease the temperature according to a certain rate, which is generally non-linear and linear. Therefore, customers should pay special attention to the difference between the two when selecting and determine the equipment according to the implemented standards.
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