Maintenance Method of High and Low Temperature Test Chamber
There are three common types of high and low temperature test chamber controllers: software failure, system failure and hardware failure.
1, Software failure:
Software failure mainly refers to the controller failure of the high and low temperature test chamber, including the internal parameters, the control point IS control and output signal of the solenoid valve on and off.
2, System failure:
System failure refers to the initial design problems of the refrigeration system, including the leakage of refrigerant caused by high and low temperature test chamber does not cool down, and refrigerant leakage is often due to transport and high and low temperature test chamber operation jitter or refrigeration copper pipe welding process is not fine and other reasons caused.
3, Hardware failure:
Hardware failure may lead to non-cooling hardware compressor, solenoid valve and other refrigeration components.
Then the user can listen and touch to roughly understand what is the hardware high and low temperature test chamber damage, if it is a compressor failure, the compressor sound will be abnormal or do not work does not start or the compressor itself temperature is much higher than usual temperature, and the solenoid valve failure and other refrigeration components failure users are not too good to master.
In addition, the damage of the controller and the damage of the electronic parts of the control refrigeration system may also cause the phenomenon of non-cooling and non-cooling of the high and low temperature test chamber.
Scientific principle of heating and cooling of high and low temperature test chamber:
The high and low temperature test chamber has the functions of heating, cooling, humidification and dehumidification, and can detect the product's high temperature resistance, low temperature resistance and humidity resistance. How is the temperature in the high and low temperature test chamber controlled?
The heating device is the key link to control whether the high and low temperature test chamber is heated up. The controller outputs voltage to the relay when it gets the heating instruction. The high and low temperature test chamber is about 3-12 volts of direct current added to the solid state relay. The AC end of the high and low temperature test chamber is equivalent to a wire connection, and the contactor is also drawn at the same time. Heat up the constant temperature and humidity test chamber.
Cooling is an important part of the high and low temperature test chamber, which directly affects the determination of a high and low temperature and performance, including compressor, condenser, throttling device, evaporator four major components, compressor is the heart of the refrigeration system, it inhales low temperature and low pressure gas, into high temperature and high pressure gas, through condensation into a liquid to release heat, through the fan to take away heat, Therefore, the test chamber is the reason of hot air, and then become low pressure liquid through throttling, and then become low temperature and low pressure gas through the evaporator back to the compressor, the refrigerant in the evaporator to absorb the heat of the high and low temperature chamber to complete the gasification process and absorb heat, to achieve the purpose of refrigeration, to complete the high and low temperature test chamber cooling process.
High and low temperature chamber temperature and cooling rate test procedure:
In the adjustable range of the temperature of the test chamber, the lowest nominal temperature was selected as the lowest cooling temperature, and the highest nominal temperature was selected as the highest heating temperature.
Open the cold source, so that the test chamber from room temperature to the lowest cooling temperature, stable for at least 3 hours, rise to the highest heating temperature, stable for at least 3 hours and then to the lowest cooling temperature, during the heating and cooling, record once a minute, until the end of the test process.
The principle of high and low temperature test chamber heating and cooling is so, the realization of its function is completed by the setting of the control system, understanding the principle of heating and cooling, in the use of high and low temperature test chamber must be more handy.
Conversion Between Accelerated Aging of Xenon Lamp Aging Test Chamber And Outdoor Aging
Generally speaking, it is difficult to have a detailed positioning and conversion formula for the conversion between accelerated aging of xenon lamp aging test chamber and outdoor aging. The biggest problem is the variability and complexity of the outdoor environment. The variables that determine the relationship between xenon lamp aging test chamber exposure and outdoor exposure include:
1. Geographical latitude of outdoor aging exposure sites (closer to the equator means more UV).
2. Altitude (Higher altitude means more UV).
3. Local geographical characteristics, such as the wind can dry the test sample or close to water will produce condensation.
4. Random changes in climate from year to year can lead to a 2:1 change in aging at the same location.
5. Seasonal changes (e.g., winter exposure may be 1/7 of summer exposure).
6. Direction of the sample (5° south vs. vertical facing north)
7. Sample insulation (outdoor samples with insulated backing age 50% faster than uninsulated samples).
8. Working cycle of xenon lamp aging box (light time and wet time).
9. The working temperature of the test chamber (the higher the temperature, the faster the aging).
10. Test the uniqueness of the sample.
11. Spectral Intensity Distribution (SPD) of laboratory light sources
Objectively speaking, accelerated aging and outdoor aging have no convertibility, one is a variable, one is a fixed value, the only thing to do is to obtain a relative value, rather than an absolute value. Of course, it is not to say that relative values have no effect; on the contrary, relative values can also be very effective. For example, you will find that a slight change in design may double the durability of standard materials. Or you may find the same looking material from multiple suppliers, some of which age quickly, most of which take a moderate amount of time to age, and a smaller amount that ages after longer exposure. Or you may find that less expensive designs have the same durability against standard materials that have satisfactory performance over actual service life, such as 5 years.
How Long Is the Xenon Lamp Weathering Test Chamber Equivalent to a Year of Outdoor Exposure?
How long is the xenon lamp weathering test chamber equivalent to a year of outdoor exposure? How to test out its durability? This is a technical problem, but also a lot of users are concerned about the problem. Today's engineers of Lab Companion are going to explain this problem.
This problem looks very simple, in fact, it is a complex problem.We can not just get a simple number, let this number and the test time of the xenon lamp weathering test chamber to multiply, so as to get the outdoor exposure time, nor is the quality of our xenon lamp weathering test chamber not good enough! No matter how good the quality of the xenon lamp weathering test chamber is, how advanced it is, it is still impossible to find only a number to solve the problem. The most important thing is that the outdoor exposure environment is complex and changeable, affected by many factors, what are the specific?
1. The influence of geographical latitude
2. The influence of altitude
3. The influence of geographical environment when testing, such as wind speed.
4. The impact of the season, winter and summer will be different, summer exposure is 7 times the damage of winter exposure.
5. Direction of the test sample
6. Is the sample insulated or uninsulated? Samples placed on insulators will generally age much faster than those not placed on insulators.
7. Test cycle of xenon lamp weathering test chamber
8. Xenon lamp weathering test chamber operating temperature, the higher the temperature, the faster the aging
9. Testing of special materials
10. Spectrum distribution in the laboratory
Industrial Computer Reliability Testing
Industrial computers can be divided into three categories according to their application attributes:
(1) Board class: includes Single Board Computer (SBC), Embedded board (Embedded Board), Black Plane, PC/104 module. (2) Subsystem class: includes single-board computers, boards, chassis, power supplies and other peripherals combined into operational subsystems, such as industrial servers and workstations. (3) System integration solutions: refers to a set of systems developed for a professional field, including the required software and hardware and surrounding, such as automatic teller machines (ATMs). The application of industrial computers widely covers ATM, POS, medical electronic equipment, game machines, gambling equipment, etc. The multi-field industry makes industrial computers must be able to withstand the use of sunlight, high and low temperature, wet and other environments, so the relevant reliability test is the focus of various manufacturers in the research and development test.
Common reliability tests for industrial computers:
(1) Wide temperature test
According to the actual application environment can be divided into four categories: 1. Outdoor: especially for the extreme low temperature or high temperature areas, such as northern Europe and desert countries, the temperature range can be from -50 to 70°C; 2. Enclosed space: for example, where heat sources are generated, such as next to a boiler, the high temperature range is about 70°C; 3. Mobile equipment: such as vehicle equipment, the high temperature can be up to 90°C according to the car area; 4. Special harsh environment: such as aerospace equipment, military, oil drilling equipment.
(2) Aging stress test
The temperature range is from -40°C to 85°C, and the temperature variation rate is 10 °C per minute for cyclic testing
(3) No wind high temperature test
At present, in order to prevent dust, industrial computers are planned to be closed and fanless in the mechanism design, so more and more manufacturers begin to pay attention to high temperature testing in a windless environment to ensure that high temperatures will not collapse
Note: For complete industrial computer test conditions, please consult LAB COMPANION
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