Structural characteristics of temperature and humidity control test chamber
Suitable for various small electrical appliances, instruments, materials, and components for wet heat testing, it is also suitable for conducting aging tests. This test chamber adopts the most reasonable structure and stable and reliable control method currently available, making it aesthetically pleasing, easy to operate, safe, and with high precision in temperature and humidity control. It is an ideal equipment for conducting constant temperature and humidity tests.
(1) The test box body is in the form of an integral structure, with the refrigeration system located at the lower rear of the box and the control system located at the upper part of the test box.
(2) Inside the air duct interlayer at one end of the studio, there are devices such as heaters, refrigeration evaporators, and fan blades distributed; On the left side of the test box, there is a Ø 50 cable hole, and the test box is a single door (stainless steel embedded door handle)
(3) The double-layer high temperature and anti-aging silicone rubber seal can effectively ensure the temperature loss of the test chamber
(4) There are observation windows, frost prevention devices, and switchable lighting fixtures on the box door. The observation window adopts multi-layer hollow tempered glass, and the inner adhesive sheet conductive film is heated and defrosted. The lighting fixtures adopt imported brand Philips lamps, which can effectively observe the experimental changes in the studio from all angles.
The refrigeration cycle of the temperature and humidity control box adopts the reverse Carnot cycle, which consists of two isothermal processes and two adiabatic processes. The process is as follows: the refrigerant is adiabatically compressed to a higher pressure by the compressor, and the work consumed increases the exhaust temperature. Then, the refrigerant exchanges heat with the surrounding medium through the condenser and transfers heat to the surrounding medium. After the refrigerant undergoes adiabatic expansion through the shut-off valve, the temperature of the refrigerant decreases. Finally, the refrigerant absorbs heat from the object at a higher temperature through the evaporator, causing the temperature of the cooled object to decrease. This cycle repeats itself to achieve the goal of cooling down.
The refrigeration system design of this test chamber applies energy regulation technology, which can ensure the normal operation of the refrigeration unit and effectively adjust the energy consumption and refrigeration capacity of the refrigeration system, so as to maintain the refrigeration system in the optimal operating state. By using Balanced Temperature Control (BTC), the control system automatically calculates the output of the heater based on the set temperature point through PID calculation when the refrigeration system is working continuously, ultimately achieving a dynamic balance.
Dear customer:
Hello, our company is a high-quality development team with strong technical strength, providing high-quality products, complete solutions, and excellent technical services to our customers. The main products include walk-in constant temperature and humidity testing chambers, UV accelerated aging testing machines, rapid temperature change testing chambers, walk-in environmental testing chambers, UV aging testers, constant temperature and humidity chambers, etc. Our company adheres to the principle of building a business with integrity, maintaining quality, and striving for progress. With a more determined pace, we continuously climb new heights and contribute to the national automation industry. We welcome new and old customers to confidently choose the products they like. We will serve you wholeheartedly!
Service conditions for high, low temperature, and low pressure test chambers
One of the usage conditions for high, low temperature, and low pressure test chambers: environmental conditions
a、 Temperature: 15 ℃~35 ℃;
b、 Relative humidity: not exceeding 85%;
c、 Atmospheric pressure: 80kPa~106kPa
d、 There is no strong vibration or corrosive gas in the surrounding area;
e、 No direct sunlight exposure or direct radiation from other cold or heat sources;
f、 There is no strong airflow around, and when the surrounding air needs to be forced to flow, the airflow should not be directly blown onto the box;
g、 The influence of magnetic field on the control circuit of the interference free test box in the surrounding area;
h、 There is no high concentration of dust or corrosive substances in the surrounding area.
Condition 2 for the use of high, low temperature, and low pressure test chambers: Power supply conditions
a、 AC voltage: 220V ± 22V or 380V ± 38V;
b、 Frequency: 50HZ ± 0.5HZ
Condition Three for the Use of High, Low Temperature, and Low Pressure Test Chambers: Water Supply Conditions
It is advisable to use tap water or circulating water that meets the following conditions:
a、 Water temperature: not higher than 30 ℃;
b、 Water pressure: 0.1MPa~0.3MPa;
c、 Water quality: meets industrial water standards.
Condition 4 for the use of high, low temperature, and low pressure test chambers: Test load conditions
The load of the test chamber should meet the following conditions every week:
a、 The total mass of the load shall not exceed 80KG per cubic meter within the working chamber volume
b、 The total volume of the load shall not exceed 5/1 of the working chamber volume
c、 On any cross-section perpendicular to the prevailing wind direction, the sum of the load areas should not exceed 3/1 of the cross-sectional area of the working chamber at that location, and the load should not obstruct the flow of airflow when placed.
Dear customer:
Our company has products such as rapid temperature change test chambers, UV accelerated weather resistance testing machines, and temperature and humidity control chambers. You can call our service hotline through our website to learn more about our products. Our pursuit is endless, and we welcome new and old customers to choose their favorite products with confidence. We will be dedicated to serving you!
User selection environment test box must read
1、 Equipment selection criteria
There is currently no exact number of natural environmental factors and induced environmental factors that exist on the surface of the Earth and in the atmosphere, among which there are no less than a dozen factors that have a significant impact on the use and lifespan of engineering products (equipment). Engineers engaged in the study of environmental conditions for engineering products have compiled and summarized the environmental conditions that exist in nature and are induced by human activities into a series of testing standards and specifications to guide the environmental and reliability testing of engineering products. For example, GJB150- the National Military Standard of the People's Republic of China for Environmental Testing of Military Equipment, and GB2423- the National Standard of the People's Republic of China for Environmental Testing of Electrical and Electronic Products, which guides environmental testing of electrical and electronic products. Therefore, the main basis for selecting environmental and reliability testing equipment is the testing specifications and standards of engineering products.
Secondly, in order to standardize the tolerance of environmental testing conditions in experimental equipment and ensure the control accuracy of environmental parameters, national technical supervision agencies and various industrial departments have also formulated a series of calibration regulations for environmental testing equipment and detection instruments. Such as the national standard GB5170 of the People's Republic of China "Basic Parameter Calibration Method for Environmental Testing Equipment of Electrical and Electronic Products", and JJG190-89 "Trial Calibration Regulations for Electric Vibration Test Stand System" issued and implemented by the State Administration of Technical Supervision. These verification regulations are also an important basis for selecting environmental and reliability testing equipment. Testing equipment that does not meet the requirements of these verification regulations is not allowed to be put into use.
2、 Basic principles for equipment selection
The selection of environmental and reliability testing equipment should follow the following five basic principles:
1. Reproducibility of environmental conditions
It is impossible to fully and accurately reproduce the environmental conditions that exist in nature in the laboratory. However, within a certain tolerance range, people can accurately and approximately simulate the external environmental conditions that engineering products undergo during use, storage, transportation, and other processes. This passage can be summarized in engineering language as follows: "The environmental conditions (including platform environment) created by the testing equipment around the tested product should meet the requirements of the environmental conditions and their tolerances specified in the product testing specifications. The temperature box used for military product testing should not only meet the requirements of the national military standards GJB150.3-86 and GJB150.4-86 for different uniformity and temperature control accuracy. Only in this way can the reproducibility of environmental conditions be ensured in environmental testing.
2. Repeatability of environmental conditions
An environmental testing equipment may be used for multiple tests of the same type of product, and a tested engineering product may also be tested in different environmental testing equipment. In order to ensure the comparability of test results obtained for the same product under the same environmental testing conditions specified in the testing specifications, it is necessary to require the environmental conditions provided by the environmental testing equipment to be reproducible. This means that the stress levels (such as thermal stress, vibration stress, electrical stress, etc.) applied by environmental testing equipment to the tested product are consistent with the requirements of the same testing specification.
The repeatability of environmental conditions provided by environmental testing equipment is guaranteed by the national metrological verification department after passing the verification according to the verification regulations formulated by the national technical supervision agency. Therefore, it is necessary to require environmental testing equipment to meet the requirements of various technical indicators and accuracy indicators in the calibration regulations, and to not exceed the time limit specified in the calibration cycle in terms of usage time. If a very common electric vibration table is used, in addition to meeting technical indicators such as excitation force, frequency range, and load capacity, it must also meet the requirements of precision indicators such as lateral vibration ratio, table acceleration uniformity, and harmonic distortion specified in the calibration regulations. Moreover, the service life after each calibration is two years, and after two years, it must be re calibrated and qualified before being put into use.
3. Measurability of environmental condition parameters
The environmental conditions provided by any environmental testing equipment must be observable and controllable. This is not only to limit the environmental parameters within a certain tolerance range and ensure the reproducibility and repeatability of the test conditions, but also necessary for the safety of product testing, in order to prevent damage to the tested product caused by uncontrolled environmental conditions and unnecessary losses. At present, various experimental standards generally require that the accuracy of parameter testing should not be less than one-third of the allowable error under experimental conditions.
4. Exclusion of environmental testing conditions
Every time an environmental or reliability test is conducted, there are strict regulations on the category, magnitude, and tolerance of environmental factors, and non test required environmental factors are excluded from penetrating into it, in order to provide a definite basis for judging and analyzing product failure and fault modes during or after the test. Therefore, it is required that environmental testing equipment not only provide the specified environmental conditions, but also not allow any other environmental stress interference to be added to the tested product. As defined in the verification regulations for electric vibration tables, the table leakage magnetic flux, acceleration signal-to-noise ratio, and total root mean square value ratio of in band and out of band acceleration. The accuracy indicators such as random signal verification and harmonic distortion are all established as verification items to ensure the uniqueness of environmental testing conditions.
5. Safety and reliability of experimental equipment
Environmental testing, especially reliability testing, has a long testing cycle and sometimes targets high-value military products. During the testing process, testing personnel often need to operate, inspect or test around the site. Therefore, it is required that environmental testing equipment must have the characteristics of safe operation, convenient operation, reliable use, and long working life to ensure the normal progress of the testing itself. The various protection, alarm measures, and safety interlock devices of the testing equipment should be complete and reliable to ensure the safety and reliability of the testing personnel, the tested products, and the testing equipment itself.
3、 Selection of Temperature and Humidity Chamber
1. Selection of Capacity
When placing the test product (components, assemblies, parts or whole machine) into a climate chamber for testing, in order to ensure that the atmosphere around the test product can meet the environmental testing conditions specified in the test specifications, the working dimensions of the climate chamber and the overall dimensions of the test product should follow the following regulations:
a) The volume of the tested product (W × D × H) shall not exceed (20-35)% of the effective working space of the test chamber (20% is recommended). For products that generate heat during testing, it is recommended to use no more than 10%.
b) The ratio of the windward cross-sectional area of the tested product to the total area of the test chamber on that section shall not exceed (35-50)% (35% is recommended).
c) The distance between the outer surface of the tested product and the wall of the test chamber should be kept at least 100-150mm (recommended 150mm).
The above three provisions are actually interdependent and unified. Taking a 1 cubic meter cube box as an example, an area ratio of 1: (0.35-0.5) is equivalent to a volume ratio of 1: (0.207-0.354). A distance of 100-150mm from the box wall is equivalent to a volume ratio of 1: (0.343-0.512).
In summary, the working chamber volume of the climate environment test chamber should be at least 3-5 times the external volume of the tested product. The reasons for making such regulations are as follows:
After the test piece is placed in the box, it occupies the smooth channel, and narrowing the channel will lead to an increase in airflow velocity. Accelerate the heat exchange between the airflow and the test piece. This is inconsistent with the reproduction of environmental conditions, as relevant standards stipulate that the air flow velocity around the test specimen in the test chamber should not exceed 1.7m/s for temperature environmental tests, in order to prevent the test specimen and the surrounding atmosphere from generating heat conduction that is not in line with reality. When unloaded, the average wind speed inside the test chamber is 0.6-0.8m/s, not exceeding 1m/s. When the space and area ratio specified in points a) and b) are met, the wind speed in the flow field may increase by (50-100)%, with an average maximum wind speed of (1-1.7) m/s. Meet the requirements specified in the standards. If the volume or windward cross-sectional area of the test piece is increased without restrictions during the experiment, the actual airflow speed during the test will exceed the maximum wind speed specified in the test standard, and the validity of the test results will be questioned.
The accuracy indicators of environmental parameters in the working chamber of the climate chamber, such as temperature, humidity, salt spray settling rate, etc., are all measured under no-load conditions. Once the test piece is placed, it will have an impact on the uniformity of the environmental parameters in the working chamber of the test chamber. The larger the space occupied by the test piece, the more severe this impact will be. Experimental data shows that the temperature difference between the windward and leeward sides in the flow field can reach 3-8 ℃, and in severe cases, it can be as high as 10 ℃ or more. Therefore, it is necessary to meet the requirements of a] and b] as much as possible to ensure the uniformity of environmental parameters around the tested product.
According to the principle of heat conduction, the temperature of the airflow near the box wall is usually 2-3 ℃ different from the temperature at the center of the flow field, and may even reach 5 ℃ at the upper and lower limits of high and low temperatures. The temperature of the box wall differs from the temperature of the flow field near the box wall by 2-3 ℃ (depending on the structure and material of the box wall). The greater the difference between the test temperature and the external atmospheric environment, the greater the temperature difference. Therefore, the space within a distance of 100-150mm from the box wall is unusable.
2. Selection of temperature range
At present, the range of temperature test chambers abroad is generally -73 to+177 ℃, or -70 to+180 ℃. Most domestic manufacturers generally operate at -80 to+130 ℃, -60 to+130 ℃, -40 to+130 ℃, and there are also high temperatures up to 150 ℃. These temperature ranges can usually meet the temperature testing needs of the vast majority of military and civilian products in China. Unless there are special requirements, such as products installed near heat sources such as engines, the upper temperature limit should not be blindly increased. Because the higher the upper limit temperature, the greater the temperature difference between the inside and outside of the box, and the poorer the uniformity of the flow field inside the box. The smaller the available studio size. On the other hand, the higher the upper limit temperature value, the higher the heat resistance requirements for insulation materials (such as glass wool) in the interlayer of the box wall. The higher the requirement for the sealing of the box, the higher the production cost of the box.
3. Selection of humidity range
The humidity indicators given by domestic and foreign environmental test chambers are mostly 20-98% RH or 30-98% RH. If the humid heat test chamber does not have a dehumidification system, the humidity range is 60-98%. This type of test chamber can only perform high humidity tests, but its price is much lower. It is worth noting that the corresponding temperature range or minimum dew point temperature should be indicated after the humidity index. Because relative humidity is directly related to temperature, for the same absolute humidity, the higher the temperature, the lower the relative humidity. For example, if the absolute humidity is 5g/Kg (referring to 5g of water vapor in 1kg of dry air), when the temperature is 29 ℃, the relative humidity is 20% RH, and when the temperature is 6 ℃, the relative humidity is 90% RH. When the temperature drops below 4 ℃ and the relative humidity exceeds 100%, condensation will occur inside the box.
To achieve high temperature and high humidity, simply spray steam or atomized water droplets into the air of the box for humidification. Low temperature and humidity are relatively difficult to control because the absolute humidity at this time is very low, sometimes much lower than the absolute humidity in the atmosphere. It is necessary to dehumidify the air flowing inside the box to make it dry. At present, the vast majority of temperature and humidity chambers both domestically and internationally adopt the principle of refrigeration and dehumidification, which involves adding a set of refrigeration light pipes to the air conditioning room of the chamber. When humid air passes through a cold pipe, its relative humidity will reach 100% RH, as the air saturates and condenses on the light pipe, making the air drier. This dehumidification method theoretically can reach dew point temperatures below zero degrees, but when the surface temperature of the cold spot reaches 0 ℃, the water droplets condensed on the surface of the light pipe will freeze, affecting the heat exchange on the surface of the light pipe and reducing the dehumidification capacity. Also, because the box cannot be completely sealed, humid air from the atmosphere will seep into the box, causing the dew point temperature to rise. On the other hand, the moist air flowing between the light tubes only reaches saturation at the moment of contact with the light tubes (cold spots) and releases water vapor, so this dehumidification method is difficult to keep the dew point temperature inside the box below 0 ℃. The actual minimum dew point temperature achieved is 5-7 ℃. A dew point temperature of 5 ℃ is equivalent to an absolute moisture content of 0.0055g/Kg, corresponding to a relative humidity of 20% RH at a temperature of 30 ℃. If a temperature of 20 ℃ and a relative humidity of 20% RH are required, with a dew point temperature of -3 ℃, it is difficult to use refrigeration for dehumidification, and an air drying system must be selected to achieve it.
4. Selection of control mode
There are two types of temperature and humidity test chambers: constant test chamber and alternating test chamber.
The ordinary high and low temperature test chamber generally refers to a constant high and low temperature test chamber, which is controlled by setting a target temperature and has the ability to automatically maintain a constant temperature to the target temperature point. The control method of the constant temperature and humidity test chamber is also similar, setting a target temperature and humidity point, and the test chamber has the ability to automatically maintain a constant temperature to the target temperature and humidity point. The high and low temperature alternating test chamber has one or more programs for setting high and low temperature changes and cycles. The test chamber has the ability to complete the test process according to the preset curve, and can accurately control the heating and cooling rates within the maximum heating and cooling rate capability range, that is, the heating and cooling rates can be controlled according to the slope of the set curve. Similarly, the high and low temperature alternating humidity test chamber also has preset temperature and humidity curves, and the ability to control them according to the preset. Of course, alternating test chambers have the function of constant test chambers, but the manufacturing cost of alternating test chambers is relatively high because they need to be equipped with curve automatic recording devices, program controllers, and solve problems such as turning on the refrigeration machine when the temperature in the working room is high. Therefore, the price of alternating test chambers is generally more than 20% higher than that of constant test chambers. Therefore, we should take the need for experimental methods as the starting point and choose a constant test chamber or an alternating test chamber.
5. Selection of variable temperature rate
Ordinary high and low temperature test chambers do not have a cooling rate indicator, and the time from the ambient temperature to the nominal lowest temperature is generally 90-120 minutes. The high and low temperature alternating test chamber, as well as the high and low temperature alternating wet heat test chamber, both have temperature change speed requirements. The temperature change speed is generally required to be 1 ℃/min, and the speed can be adjusted within this speed range. The rapid temperature change test chamber has a fast temperature change rate, with heating and cooling rates ranging from 3 ℃/min to 15 ℃/min. In certain temperature ranges, the heating and cooling rates can even reach over 30 ℃/min.
The temperature range of various specifications and speeds of rapid temperature change test chambers is generally the same, that is, -60 to+130 ℃. However, the temperature range for assessing the cooling rate is not the same. According to different test requirements, the temperature range of rapid temperature change test chambers is -55 to+80 ℃, while others are -40 to+80 ℃.
There are two methods for determining the temperature change rate of the rapid temperature change test chamber: one is the average temperature rise and fall rate throughout the entire process, and the other is the linear temperature rise and fall rate (actually the average speed every 5 minutes). The average speed throughout the entire process refers to the ratio of the difference between the highest and lowest temperatures within the temperature range of the test chamber to the time. At present, the technical parameters of temperature change rate provided by various environmental testing equipment manufacturers abroad refer to the average rate throughout the entire process. The linear temperature rise and fall rate refers to the guaranteed temperature change rate within any 5-minute time period. In fact, for the rapid temperature change test chamber, the most difficult and critical stage to ensure the linear temperature rise and fall speed is the cooling rate that the test chamber can achieve during the last 5 minutes of the cooling period. From a certain perspective, the linear heating and cooling speed (average speed every 5 minutes) is more scientific. Therefore, it is best for the experimental equipment to have two parameters: the average temperature rise and fall speed throughout the entire process and the linear temperature rise and fall speed (average speed every 5 minutes). Generally speaking, the linear heating and cooling speed (average speed every 5 minutes) is half of the average heating and cooling speed throughout the entire process.
6. Wind speed
According to relevant standards, the wind speed inside the temperature and humidity chamber during environmental testing should be less than 1.7m/s. For the test itself, the lower the wind speed, the better. If the wind speed is too high, it will accelerate the heat exchange between the surface of the test piece and the airflow inside the chamber, which is not conducive to the authenticity of the test. But in order to ensure uniformity within the testing chamber, it is necessary to have circulating air inside the testing chamber. However, for rapid temperature change test chambers and comprehensive environmental test chambers with multiple factors such as temperature, humidity, and vibration, in order to pursue the rate of temperature change, it is necessary to accelerate the flow velocity of the circulating airflow inside the chamber, usually at a speed of 2-3m/s. Therefore, the wind speed limit varies for different usage purposes.
7. Temperature fluctuation
Temperature fluctuation is a relatively easy parameter to implement, and most test chambers produced by environmental testing equipment manufacturers can actually control temperature fluctuations within a range of ± 0.3 ℃.
8. Uniformity of temperature field
In order to simulate the actual environmental conditions that products experience in nature more accurately, it is necessary to ensure that the surrounding area of the tested product is under the same temperature environment conditions during environmental testing. Therefore, it is necessary to limit the temperature gradient and temperature fluctuation inside the test chamber. In the General Principles of Environmental Test Methods for Military Equipment (GJB150.1-86) of the National Military Standard, it is clearly stipulated that "the temperature of the measurement system near the test sample should be within ± 2 ℃ of the test temperature, and its temperature should not exceed 1 ℃/m or the total maximum value should be 2.2 ℃ (when the test sample is not working).
9. Precision control of humidity
The humidity measurement in the environmental testing chamber mostly adopts the dry wet bulb method. The manufacturing standard GB10586 for environmental testing equipment requires that the relative humidity deviation should be within ± 23% RH. To meet the requirements of humidity control accuracy, the temperature control accuracy of the humidity test chamber is relatively high, and the temperature fluctuation is generally less than ± 0.2 ℃. Otherwise, it will be difficult to meet the requirements for humidity control accuracy.
10. Cooling method selection
If the test chamber is equipped with a refrigeration system, the refrigeration system needs to be cooled. There are two forms of test chambers: air-cooled and water-cooled.
Forced air cooling
Water-cooling
Working conditions
The equipment is easy to install, only need to power on.
The ambient temperature should be lower than 28℃. If the ambient temperature is higher than 28℃, it has a certain impact on the refrigeration effect (preferably with air conditioning), the circulating cooling water system should be configured.
Heat exchange effect
Poor (relative to the water-cooling mode)
Stable, good
Noise
Large (relative to the water-cooling mode)
Less
The walk-in high and low temperature (humid and hot) laboratory also needs maintenance
Reminder: Remember to maintain the walk-in high and low temperature (humid and hot) laboratory as well!
1. The temperature and humidity testing system of the walk-in high and low temperature (humid and hot) laboratory must be operated and maintained by a dedicated person. Strictly follow the operating procedures of the system and avoid others from operating the system illegally.
2. Long term shutdown of the walk-in high and low temperature (humid and hot) laboratory can affect the effective service life of the system. Therefore, the system should be turned on and operated at least once every 10 days; Do not repeatedly stop the system in a short period of time. The number of starts per hour should be less than 5 times, and the time interval between each start stop should not be less than 3 times; Do not open the door of the walk-in temperature and humidity testing system at low temperatures to prevent damage to the door sealing tape.
3. A system usage file should be established to facilitate system maintenance and repair. The use of archives should record the start and end time (date) of each system operation, the type of experiment, and the ambient temperature; When the system malfunctions, provide a detailed description of the fault phenomenon as much as possible; The maintenance and repair of the system should also be recorded in as much detail as possible.
4. Conduct a monthly main power switch (leakage circuit breaker) operation test to ensure that the switch is used as a leakage protector while meeting the load capacity. The specific steps are as follows: first, please confirm that the main power switch is turned to "ON", which means the system is powered on, and then press the test button. If the switch lever of the residual current circuit breaker falls down, this function is normal.
5. The main box of the walk-in temperature and humidity testing system should be protected during use and should not be subjected to strong impacts from sharp or blunt objects.
6. To ensure the normal and clean supply of cooling water, the cooling water filter of the refrigeration unit should be cleaned every 30 days. If the local air quality is poor and the dust content in the air is high, the cooling water tower reservoir should generally be cleaned every 7 days.
7. The leakage, overload, and short-circuit protection characteristics of the residual current switch are set by Lab Companion manufacturer and cannot be adjusted arbitrarily during use to avoid affecting performance; After the leakage switch is disconnected due to a short circuit, the contacts need to be checked. If the main contacts are severely burned or have pits, maintenance is required.
8. The test products placed in the walk-in temperature and humidity testing system should be kept at a certain distance from the suction and exhaust ports of the air conditioning channel to avoid obstructing air circulation.
9. Overtemperature protector action test. Set the temperature of the over temperature protector to be lower than the temperature of the box. If there is an E0.0 alarm and buzzing sound, it indicates that its function is normal. After completing the above experiment, the temperature protection setting should be reset appropriately, otherwise it may cause inappropriate termination.
10. Once a year, use a vacuum cleaner to clean and remove dust from the distribution room and water circuit room. Once a month, use a dry cloth to clean the accumulated water in the water tray of the refrigeration unit.
Maintenance of refrigeration compressor for constant temperature and humidity test chamber, cold and hot shock test chamber
Article summary: For environmental monitoring equipment, the only way to maintain long-term and stable use is to pay attention to maintenance in all aspects. Here, we will introduce the maintenance of the compressor, which is an important component of the constant temperature and humidity test chamber and the cold and hot shock test chamber
Detailed content:
Maintenance plan for refrigeration compressor:
As the core component of the refrigeration system in the constant temperature and humidity test chamber, the maintenance of the compressor is essential. Guangdong Hongzhan Technology Co., Ltd. introduces the daily maintenance steps and precautions for the compressor in the constant temperature and humidity test chamber and the cold and hot shock test chamber
1、 Carefully check the sound of the cylinders and moving parts at all levels to determine if their working condition is normal. If any abnormal sound is found, immediately stop the machine for inspection;
2、 Pay attention to whether the indicated values of pressure gauges at all levels, pressure gauges on gas storage tanks and coolers, and lubricating oil pressure gauges are within the specified range;
3、 Check if the temperature and flow rate of the cooling water are normal;
4、 Check the supply of lubricating oil and the lubrication system of the moving mechanism (some compressors are equipped with organic glass baffles on the side of the cross head guide rail of the machine body),
You can directly see the movement of the crosshead and the supply of lubricating oil; The cylinder and packing can be inspected for oil discharge using a one-way valve, which can check if the oil injector is inserted into the cylinder
Oil injection situation;
5、 Observe whether the oil level in the body oil tank and the lubricating oil in the oil injector are below the scale line. If they are low, they should be refilled in a timely manner (if using a dipstick, stop and check);
6、 Check the temperature of the intake and exhaust valve covers at the cross guide rail of the crankcase with your hand to see if it is normal;
7、 Pay attention to the temperature rise of the motor, bearing temperature, and whether the readings on the voltmeter and ammeter are normal. The current should not exceed the rated current of the motor. If it exceeds the rated current, the cause should be identified or the machine should be stopped for inspection;
8、 Regularly check whether there are any debris or conductive objects inside the motor, whether the coil is damaged, and whether there is friction between the stator and rotor, otherwise the motor will burn out after starting;
9、 If it is a water-cooled compressor and water cannot be immediately supplied after the water is cut off, it is necessary to avoid cylinder cracking due to uneven heating and cooling. After parking in winter, the cooling water should be drained to prevent freezing and cracking of the cylinder and other parts;
10、 Check whether the compressor vibrates and whether the foundation screws are loose or detached;
11、 Check whether the pressure regulator or load regulator, safety valve, etc. are sensitive;
12、 Pay attention to the hygiene of the compressor, its associated equipment, and the environment;
13、 Gas storage tanks, coolers, and oil-water separators should regularly release oil and water;
14、 The lubricating machine used should be filtered by sedimentation. Differentiate the use of compressor oil between winter and summer
Conduction Zone of Heat
Thermal conductivity
It is the thermal conductivity of a substance, passing from high temperature to low temperature within the same substance. Also known as: thermal conductivity, thermal conductivity, thermal conductivity, heat transfer coefficient, heat transfer, thermal conductivity, thermal conductivity, thermal conductivity, thermal conductivity.
Thermal conductivity formula
k = (Q/t) *L/(A*T) k: thermal conductivity, Q: heat, t: time, L: length, A: area, T: temperature difference in SI units, the unit of thermal conductivity is W/(m*K), in imperial units, is Btu · ft/(h · ft2 · °F)
Heat transfer coefficient
In thermodynamics, mechanical engineering and chemical engineering, the heat conductivity is used to calculate the heat conduction, mainly the heat conduction of convection or the phase transformation between fluid and solid, which is defined as the heat through the unit area per unit time under the unit temperature difference, called the heat conduction coefficient of the substance, if the thickness of the mass of L, the measurement value to be multiplied by L, The resulting value is the coefficient of thermal conductivity, usually denoted as k.
Unit conversion of heat conduction coefficient
1 (CAL) = 4.186 (j), 1 (CAL/s) = 4.186 (j/s) = 4.186 (W).
The impact of high temperature on electronic products:
The rise in temperature will cause the resistance value of the resistor to decrease, but also shorten the service life of the capacitor, in addition, the high temperature will cause the transformer, the performance of the related insulation materials to decrease, the temperature is too high will also cause the solder joint alloy structure on the PCB board to change: IMC thickens, solder joints become brittle, tin whisker increases, mechanical strength decreases, junction temperature increases, the current amplification ratio of transistor increases rapidly, resulting in collector current increases, junction temperature further increases, and finally component failure.
Explanation of proper terms:
Junction Temperature: The actual temperature of a semiconductor in an electronic device. In operation, it is usually higher than the Case Temperature of the package, and the temperature difference is equal to the heat flow multiplied by the thermal resistance. Free convection (natural convection) : Radiation (radiation) : Forced Air(gas cooling) : Forced Liquid (gas cooling) : Liquid Evaporation: Surface Surroundings Surroundings
Common simple considerations for thermal design:
1 Simple and reliable cooling methods such as heat conduction, natural convection and radiation should be used to reduce costs and failures.
2 Shorten the heat transfer path as much as possible, and increase the heat exchange area.
3 When installing components, the influence of radiation heat exchange of peripheral components should be fully considered, and the thermal sensitive devices should be kept away from the heat source or find a way to use the protective measures of the heat shield to isolate the components from the heat source.
4 There should be sufficient distance between the air inlet and the exhaust port to avoid hot air reflux.
5 The temperature difference between the incoming air and the outgoing air should be less than 14 ° C.
6 It should be noted that the direction of forced ventilation and natural ventilation should be consistent as far as possible.
7 Devices with large heat should be installed as close as possible to the surface that is easy to dissipate heat (such as the inner surface of the metal casing, metal base and metal bracket, etc.), and there is good contact heat conduction between the surface.
8 Power supply part of the high-power tube and rectifier bridge pile belong to the heating device, it is best to install directly on the housing to increase the heat dissipation area. In the layout of the printed board, more copper layers should be left on the board surface around the larger power transistor to improve the heat dissipation capacity of the bottom plate.
9 When using free convection, avoid using heat sinks that are too dense.
10 The thermal design should be considered to ensure that the current carrying capacity of the wire, the diameter of the selected wire must be suitable for the conduction of the current, without causing more than the allowable temperature rise and pressure drop.
11 If the heat distribution is uniform, the spacing of the components should be uniform to make the wind flow evenly through each heat source.
12 When using forced convection cooling (fans), place the temperature-sensitive components closest to the air intake.
13 The use of free convection cooling equipment to avoid arranging other parts above the high power consumption parts, the correct approach should be uneven horizontal arrangement.
14 If the heat distribution is not uniform, the components should be sparsely arranged in the area with large heat generation, and the component layout in the area with small heat generation should be slightly denser, or add a diversion bar, so that the wind energy can effectively flow to the key heating devices.
15 The structural design principle of the air inlet: on the one hand, try to minimize its resistance to the air flow, on the other hand, consider dust prevention, and comprehensively consider the impact of the two.
16 Power consumption components should be spaced as far apart as possible.
17 Avoid crowding temperature sensitive parts together or arranging them next to high power consuming parts or hot spots.
18 The use of free convection cooling equipment to avoid arranging other parts above the high power consumption parts, the correct practice should be uneven horizontal arrangement.
Temperature Cyclic Stress Screening (1)
Environmental Stress Screening (ESS)
Stress screening is the use of acceleration techniques and environmental stress under the design strength limit, such as: burn in, temperature cycling, random vibration, power cycle... By accelerating the stress, the potential defects in the product emerge [potential parts material defects, design defects, process defects, process defects], and eliminate electronic or mechanical residual stress, as well as eliminate stray capacitors between multi-layer circuit boards, the early death stage of the product in the bath curve is removed and repaired in advance, so that the product through moderate screening, Save the normal period and decline period of the bathtub curve to avoid the product in the process of use, the test of environmental stress sometimes lead to failure, resulting in unnecessary losses. Although the use of ESS stress screening will increase the cost and time, for improving the product delivery yield and reduce the number of repairs, there is a significant effect, but for the total cost will be reduced. In addition, customer trust will also be improved, generally for electronic parts of the stress screening methods are pre-burning, temperature cycle, high temperature, low temperature, PCB printed circuit board stress screening method is temperature cycle, for the electronic cost of the stress screening is: Power pre-burning, temperature cycling, random vibration, in addition to the stress screen itself is a process stage, rather than a test, screening is 100% of the product procedure.
Stress screening applicable product stage: R & D stage, mass production stage, before delivery (screening test can be carried out in components, devices, connectors and other products or the whole machine system, according to different requirements can have different screening stress)
Stress screening comparison:
a. Constant high temperature pre-burning (Burn in) stress screening, is the current electronic IT industry commonly used method to precipitate electronic components defects, but this method is not suitable for screening parts (PCB, IC, resistor, capacitor), According to statistics, the number of companies in the United States that use temperature cycling to screen parts is five times more than the number of companies that use constant high temperature prefiring to screen components.
B. GJB/DZ34 indicates the proportion of temperature cycle and random vibrating screen selection defects, temperature accounted for about 80%, vibration accounted for about 20% of the defects in various products.
c. The United States has conducted a survey of 42 enterprises, random vibration stress can screen out 15 to 25% of the defects, while the temperature cycle can screen out 75 to 85%, if the combination of the two can reach 90%.
d. The proportion of product defect types detected by temperature cycling: insufficient design margin: 5%, production and workmanship errors: 33%, defective parts: 62%
Description of fault induction of temperature cyclic stress screening:
The cause of product failure induced by temperature cycling is: when the temperature is cycled within the upper and lower extremal temperatures, the product produces alternating expansion and contraction, resulting in thermal stress and strain in the product. If there is a transient thermal ladder (temperature non-uniformity) within the product, or the thermal expansion coefficients of adjacent materials within the product do not match each other, these thermal stresses and strains will be more drastic. This stress and strain is greatest at the defect, and this cycle causes the defect to grow so large that it can eventually cause structural failure and generate electrical failure. For example, a cracked electroplated through-hole eventually cracks completely around it, causing an open circuit. Thermal cycling enables soldering and plating through holes on printed circuit boards... Temperature cyclic stress screening is especially suitable for electronic products with printed circuit board structure.
The fault mode triggered by the temperature cycle or the impact on the product is as follows:
a. The expansion of various microscopic cracks in the coating, material or wire
b. Loosen poorly bonded joints
c. Loosen improperly connected or riveted joints
d. Relax the pressed fittings with insufficient mechanical tension
e. Increase the contact resistance of poor quality solder joints or cause an open circuit
f. Particle, chemical pollution
g. Seal failure
h. Packaging issues, such as bonding of protective coatings
i. Short circuit or open circuit of the transformer and coil
j. The potentiometer is defective
k. Poor connection of welding and welding points
l. Cold welding contact
m. Multi-layer board due to improper handling of open circuit, short circuit
n. Short circuit of power transistor
o. Capacitor, transistor bad
p. Dual row integrated circuit failure
q. A box or cable that is nearly short-circuited due to damage or improper assembly
r. Breakage, breakage, scoring of material due to improper handling... Etc.
s. out-of-tolerance parts and materials
t. resistor ruptured due to lack of synthetic rubber buffer coating
u. The transistor hair is involved in the grounding of the metal strip
v. Mica insulation gasket rupture, resulting in short circuit transistor
w. Improper fixing of the metal plate of the regulating coil leads to irregular output
x. The bipolar vacuum tube is open internally at low temperature
y. Coil indirect short circuit
z. Ungrounded terminals
a1. Component parameter drift
a2. Components are improperly installed
a3. Misused components
a4. Seal failure
Introduction of stress parameters for temperature cyclic stress screening:
The stress parameters of temperature cyclic stress screening mainly include the following: high and low temperature extremum range, dwell time, temperature variability, cycle number
High and low temperature extremal range: the larger the range of high and low temperature extremal, the fewer cycles required, the lower the cost, but can not exceed the product can withstand the limit, do not cause new fault principle, the difference between the upper and lower limits of temperature change is not less than 88°C, the typical range of change is -54°C to 55°C.
Dwell time: In addition, the dwell time can not be too short, otherwise it is too late to make the product under test produce thermal expansion and contraction stress changes, as for the dwell time, the dwell time of different products is different, you can refer to the relevant specification requirements.
Number of cycles: As for the number of cycles of temperature cyclic stress screening, it is also determined by considering product characteristics, complexity, upper and lower limits of temperature and screening rate, and the screening number should not be exceeded, otherwise it will cause unnecessary harm to the product and cannot improve the screening rate. The number of temperature cycles ranges from 1 to 10 cycles [ordinary screening, primary screening] to 20 to 60 cycles [precision screening, secondary screening], for the removal of the most likely workmanship defects, about 6 to 10 cycles can be effectively removed, in addition to the effectiveness of the temperature cycle, Mainly depends on the temperature variation of the product surface, rather than the temperature variation inside the test box.
There are seven main influencing parameters of temperature cycle:
(1) Temperature Range
(2) Number of Cycles
(3) Temperature Rate of Chang
(4) Dwell Time
(5) Airflow Velocities
(6) Uniformity of Stress
(7) Function test or not (Product Operating Condition)
Temperature Cycling Test
Temperature Cycling, in order to simulate the temperature conditions encountered by different electronic components in the actual use environment, changing the ambient temperature difference range and rapid rise and fall temperature change can provide a more stringent test environment, but it must be noted that additional effects may be caused to material testing. For the relevant international standard test conditions of temperature cycle test, there are two ways to set the temperature change. Macroshow Technology provides an intuitive setting interface, which is convenient for users to set according to the specification. You can choose the total Ramp time or set the rise and cooling rate with the temperature change rate per minute.
List of international specifications for temperature cycling tests:
Total Ramp time (min) : JESD22-A104, MIL-STD-8831, CR200315
Temperature variation per minute (℃/min) : IEC 60749, IPC-9701, Bellcore-GR-468, MIL-2164
Example: Lead-free solder joint reliability test
Instructions: For the reliability test of lead-free solder joints, different test conditions will also be different in terms of the temperature change setting mode. For example, (JEDEC JESD22-A104) will specify the temperature change time with the total time [10min], while other conditions will specify the temperature change rate with [10℃/ min], such as from 100 ℃ to 0℃. With a temperature change of 10 degrees per minute, that is to say, the total temperature change time is 10 minutes.
100℃ [10min]←→0℃[10min], Ramp: 10℃/ min, 6500cycle
-40℃[5min]←→125℃ [5min], Ramp: 10min,
200cycle check once, 2000cycle tensile test [JEDEC JESD22-A104]
-40℃(15min)←→125℃(15min), Ramp: 15min, 2000cycle
Example: LED Automotive lighting (High Power LED)
The temperature cycle test condition of LED car lights is -40 ° C to 100 ° C for 30 minutes, the total temperature change time is 5 minutes, if converted into temperature change rate, it is 28 degrees per minute (28 ° C /min).
Test conditions: -40℃(30min)←→100℃(30min), Ramp: 5min
Испытание пластины VMR на кратковременный температурный циклИспытание температурным циклом является одним из наиболее часто используемых методов проверки надежности и срока службы бессвинцовых сварочных материалов и деталей SMD. Он оценивает клеевые детали и паяные соединения на поверхности SMD и вызывает пластическую деформацию и механическую усталость материалов паяных соединений под усталостным эффектом холодного и горячего температурного цикла с контролируемой изменчивостью температуры, чтобы понять потенциальные опасности и факторы отказа. паяных соединений и SMD. Схема шлейфового подключения подключается между деталями и паяными соединениями. В процессе испытаний выявляются включения-выключения и включения-выключения между линиями, деталями и паяными соединениями с помощью высокоскоростной системы измерения мгновенного разрыва, которая отвечает требованиям проверки надежности электрических соединений для оценки наличия паяных соединений, оловянных шариков. и детали выходят из строя. Этот тест на самом деле не симулируется. Его цель — создать сильную нагрузку и ускорить процесс старения испытуемого объекта, чтобы подтвердить, правильно ли спроектирован или изготовлен продукт, а затем оценить срок службы паяных соединений компонентов при термической усталости. Испытание надежности электрического высокоскоростного мгновенного разрыва соединения стало ключевым звеном, обеспечивающим нормальную работу электронной системы и предотвращающим выход из строя электрического соединения, вызванный отказом незрелой системы. Изменение сопротивления за короткий период времени наблюдалось при ускоренном изменении температуры и вибрационных испытаниях.Цель:1. Убедитесь, что спроектированная, изготовленная и собранная продукция соответствует заранее установленным требованиям.2. Ослабление напряжения ползучести паяного соединения и разрушение SMD, вызванное разницей теплового расширения.3. Максимальная испытательная температура температурного цикла должна быть на 25 ℃ ниже, чем температура Tg материала печатной платы, чтобы избежать более одного механизма повреждения заменяющего испытательного продукта.4. Изменение температуры со скоростью 20 ℃/мин представляет собой температурный цикл, а изменение температуры выше 20 ℃/мин является температурным шоком.5. Интервал динамических измерений сварного соединения не превышает 1 мин.6. Время пребывания при высокой и низкой температуре для определения неисправности необходимо измерить за 5 ходов.Требования:1. Общее время пребывания при температуре испытуемого продукта находится в пределах номинальной максимальной температуры и минимальной температуры, а продолжительность времени пребывания очень важна для ускоренного испытания, поскольку времени пребывания недостаточно во время ускоренного испытания. , что сделает процесс ползучести незавершенным2. Местная температура должна быть выше температуры Tmax и ниже температуры Tmin.См. список технических характеристик:IPC-9701, IPC650-2.6.26, IPC-SM-785, IPCD-279, J-STD-001, J-STD-002, J-STD-003, JESD22-A104, JESD22-B111, JESD22-B113, ДЖЕСД22-Б117, СДЖР-01
EC-85MHPM-W, бак для высокой нагрузки, соответствующий постоянной температуре и влажности (800 л)ПроектТипРядＭＨＰＭ－ＷФункцияРежим температуры и влажностиПуть мокрого мячадиапазон температур-40 ～ + 100 ℃Диапазон влажности20 ~ 98% относительной влажности(По анафазе 3)Изменения температуры и влажности± 0,3 ℃ ／ ± 2,5% относительной влажностиРаспределение температуры и влажности± 0,5 ℃ ／ ± 5,0% относительной влажностиТемпература падает со временем+20 ～ -40 ℃75 днейВремя повышения температуры-40 ～ + 100 ℃50 днейИсследовался внутренний объем матки.800 ＬДюймовый метод испытательной комнаты (ширина, глубина и высота)1000 мм × 800 мм × 1000 ммДюймовый метод продукта (ширина, глубина и высота)1400 мм × 1190 мм × 1795 ммСделать материалВнешний нарядПанель управления испытательной комнатоймашинное помещениеХолодная стальная пластина, холодная стальная пластина бежевого цвета(Таблица цветов 2,5Y8/2)ВнутриПластина из нержавеющей стали (SUS304,2B полированная)Сломанный нагревательный материалТестовая маткаТвердая синтетическая смола―ДверьТвердый вспененный хлопок из синтетической смолы, стеклянный хлопокПроектТипРядＭＨＰＭ－ＷУдаление охлаждения, мокрое устройство Метод охлаждения Режим механической усадки секции Охлаждающая средаＲ４０４ＡЧеловек может сжать машинуРезультат (количество сотрудников)1,5 кВт （１）Охлаждение и осушительМногоканальный смешанный тип радиатораКонденсаторМногоканальный смешанный радиатор радиатора (воздушное охлаждение)КалорификаторФормаНагреватель из никель-хромового жаростойкого сплаваОбъем3,5 кВт Увлажнитель ФормаГенерация параОбъем1,8 кВт×2воздуходувкаФормаМногоканальный смешанный радиатор радиатора (воздушное охлаждение)Мощность двигателя40 ВтБлок питательной водыЦилиндр подачи воды Способ подачи водыКачество водыЧистая вода ＊ Автоматическая подача воды（"Пожалуйста, обратитесь к автоматической подаче воды."）Объем Тип гравитации Увлажняющий диск Тип гравитации КонтроллерДиапазон настройки температуры-42,0 ～ + 102,0 ℃Диапазон настройки влажности0 ~ 98% относительной влажности (температура по сухому термометру 10 ~ 85 ℃)Диапазон установки времени0 ~ 999 Время 59 минут (тип настройки программы) 0 ~ 20000 Время 59 минут (тип значения)Установить энергию разложенияТемпература 0,1℃, относительная влажность 1% в течение 1 мин.Укажите точностьТемпература ± 0,8 ℃ (tp.), влажность ± 1% относительной влажности (tp.), время ± 100 ppm.Тип отпускаЦенность или программаНомер этапа20 этапов/1 программаКоличество процедурМаксимальное количество входящих форсированных (ОЗУ) программ — 32 программы.Максимальное количество внутренних программ ПЗУ — 13 программ.Номер туда и обратно максимум 98 раз или неограниченноКоличество повторов туда и обратноМаксимум 3 тяжелыхСместить конецPt 100 Ом （ при 0 ℃ ）, класс Ｂ（ JIS C 1604-1997 ）Контрольное действиеПри разделении действия ПИДВнутренняя функцияФункция ранней доставки, функция ожидания, функция поддержания заданного значения, функция защиты от отключения электроэнергии,Функция выбора силового действия, функция обслуживания, функция транспортировки туда и обратно,Функция доставки времени, функция вывода сигнала времени, функция предотвращения превышения и переохлаждения,Функция представления отклонений от нормы, функция вывода внешней тревоги, функция представления парадигмы настройки,Функция выбора типа транспорта, время расчета представляет собой функцию, функцию лампы щелевой лампыПроектТипРядＭＨＰＭ－ＷПанель управленияОборудование машиныЖК-панель управления (типа контактная панель),Обозначает лампу (силовую, транспортную, аномальную), клемму тестового источника питания, клемму внешней сигнализации,Выходной разъем сигнала времени, разъем шнура питания Защитное устройство Холодильный циклУстройство защиты от перегрузки, устройство высокой блокировкиКалорификаторУстройство защиты от превышения температуры, температурный предохранительУвлажнитель Устройство предотвращения пригорания воздуха, регулятор уровня воды увлажняющего дискавоздуходувкаУстройство защиты от перегрузкиПанель управленияПрерыватель утечки электропитания, предохранитель (для обогревателя, увлажнителя),Предохранитель (для рабочего контура), устройство защиты от повышения температуры (для проверки),Устройство предотвращения переохлаждения при повышении температуры (тестовый материал, в микрокомпьютере)Вторичная продукция (наборы)Приемник домика (4), доска домика (2), фитиль для мокрого мяча (15), инструкция по эксплуатации (1)Продукция оборудованияАдвентицияТвердое боросиликатное стекло 800×800 мм.2Отверстие для кабеляРазмер отверстия 50 мм１Корыто внутри лампыAC100V 15W Белый горячий шар２Колесо ４Горизонтальная регулировка ４Характеристики электровирусаИсточник Переменный ток трехфазный 380В 50ГцМаксимальный ток нагрузки25АМощность прерывателя утечки для источника питания50А
Комплексный испытательный стендОсобенности оборудования:Может быть подключен к вертикальному вибрационному столу или одновременно к вертикальному и горизонтальному вибрационному столу;Вы можете выбрать такие функции, как подъем устройства и перевод устройства;Высокая прочность и высокая надежность конструкции – обеспечение высокой надежности оборудования;Материал студии - нержавеющая сталь SUS304 - с высокой коррозионной стойкостью, функцией холодной и горячей усталости и длительным сроком службы;Изоляционный материал из пенополиуретана высокой плотности – обеспечение минимальных теплопотерь;Обработка поверхности распылением – обеспечение длительной антикоррозионной функции и долговечности внешнего вида оборудования;Уплотнительная лента из высокопрочной термостойкой силиконовой резины – обеспечивает высокую герметизацию дверец оборудования;Множество дополнительных функций (таких как контрольные отверстия, самописцы, системы очистки воды и т. д.) гарантируют, что у пользователей будет множество функций и потребностей в тестировании;Электрическое смотровое окно с защитой от замерзания большой площади и скрытое освещение - могут обеспечить хороший эффект наблюдения;Экологически чистые хладагенты – убедитесь, что оборудование лучше соответствует вашим требованиям по защите окружающей среды;Настраиваемый размер/индикаторы использования/различные дополнительные функции в соответствии с требованиями пользователяКонтроль температурыМожно добиться постоянного контроля температуры и программного управления;Регистратор данных всего процесса (дополнительная функция) позволяет обеспечить полную запись процесса и прослеживаемость экспериментального процесса;Каждый двигатель оснащен защитой от перегрузки по току (перегреву)/защитой от короткого замыкания нагревателя, обеспечивающей высокую надежность притока воздуха и нагрева во время работы оборудования;Интерфейс USB и функция связи Ethernet позволяют использовать функции связи и расширения программного обеспечения устройства для удовлетворения различных потребностей клиентов;Используя популярный во всем мире режим управления охлаждением, мощность охлаждения компрессора можно автоматически регулировать от 0% до 100%, что снижает потребление энергии на 30% по сравнению с традиционным режимом управления температурой теплового баланса;Ключевые компоненты холодильного оборудования и электрического управления изготовлены из продукции всемирно известных брендов, что улучшает и обеспечивает общее качество оборудования;Оборудование соответствует следующим стандартамGB/T 10592-2008 Технические условия для Камеры для испытаний при высоких и низких температурахGB/T 10586-2006 Технические условия для испытательной камеры влажного теплаGB/T 2423.1-2008 Экологические испытания электрических и электронных изделий. Часть 2. Методы испытаний. Испытание A: Низкая температура.GB/T 2423.2-2008 Экологические испытания электрических и электронных изделий. Часть 2. Методы испытаний. Испытание B: Высокая температура.GB/T 2423.3-2006 Экологические испытания электрических и электронных изделий. Часть 2. Методы испытаний. Испытательная кабина: испытание при постоянном влажном нагреве.GB/T 2423.4-2008 Экологические испытания электрических и электронных изделий. Часть 2. Методы испытаний. База испытаний: переменное влажное тепло (цикл 12 часов + 12 часов)GB/T 2423.22-2008 Экологические испытания электрических и электронных изделий. Часть 2. Методы испытаний. Испытание N: Изменения температуры.GB/T 5170.1-2008 Общие принципы методов проверки оборудования для испытаний на воздействие окружающей среды для электрических и электронных изделийGJB 150.3A-2009 Методы испытаний на воздействие окружающей среды в лаборатории военной техники. Часть 3: Испытание при высоких температурах.GJB 150.4A-2009 Методы испытаний на воздействие окружающей среды в лаборатории военной техники. Часть 4: Испытание при низкой температуре.GJB 150.9A-2009 Методы испытаний на воздействие окружающей среды в лаборатории военной техники. Часть 9: Испытание на влажную жару.Выбор различных корпусов вибростолов может соответствовать различным стандартным методам испытаний на вибрацию.(например, GB/T 2423.35-2005, GB/T 2423.36-2005 и т. д.).Три комплексные испытательные камеры; Три комплексные испытательные камеры для измерения температуры, влажности и вибрации; Технические характеристики на температуру/влажность/вибрацию/три комплексных испытательных оборудования.модельТХВ-500ТХВ-1000ТХВ-1500внутреннее измерениеD7009001250W80011501150H90011001100Размер подключения вибрационного стола (мм)Горизонтальная стойка ≤400*400 Вертикальная платформа≤Φ400Горизонтальная стойка ≤600*600 Вертикальная платформа≤Φ600 Одиночная вертикальная платформа≤Φ630 ммГоризонтальная стойка ≤900*900 Вертикальная платформа≤Φ900Высота крышки двигателя (мм)235ИсточникAC380V.50HZ Трехфазная четырехпроводная система + заземляющий проводСтандартная планировкаОдно руководство по продукту, один отчет об испытаниях, один сертификат качества и гарантия качества, 2 панели, 2 полоски, одна глухая плата, один комплект интерфейсной платы, один комплект мягкой заглушки из силиконовой резины.СтруктураХаллНапыление холоднокатаной стальной пластины (цвета слоновой кости) Внутренний резервуарЛист и пластина из нержавеющей сталиТеплоизоляционный материал ПенополиуретанОхлаждение Метод охлажденияРежим охлаждения многоярусного компрессора (с водяным охлаждением)ХолодильникНемецкий полузакрытый компрессор с долинным колесомОкно наблюдения (мм) 400*500 Соединение прибора (мм)По одному слева и справа Φ100КонтроллерЦветной ЖК-дисплей с сенсорным экраномЗаписывающее устройствоРегистратор температуры и влажности (опция) Интерфейс связиИнтерфейс RS485. Интерфейс RS232. Программное обеспечение для управления компьютером в верхнем положении (опция)
Условия испытания поляризатораПоляризатор является одной из основных частей жидкокристаллического дисплея. Это световая пластина, которая пропускает свет только в определенном направлении. В процессе изготовления жидкокристаллической пластины его необходимо использовать над и под каждой деталью, а также в расположение в шахматном порядке, в основном используется для электрического поля и отсутствия электрического поля, когда источник света создает разность фаз и состояние света и темноты, для отображения субтитров или шаблонов.Соответствующие условия испытаний:Поскольку молекулярная структура йода легко разрушается в условиях высокой температуры и влажности, долговечность поляризатора, изготовленного по технологии окрашивания йодом, низкая и обычно может соответствовать только:Высокая температура: 80℃×500HRЖарко и влажно: рабочие условия ниже 60℃×90% относительной влажности×500ч.Однако с расширением использования ЖК-продуктов влажные и горячие условия работы поляризационных продуктов становятся все более и более требовательными, и существует спрос на продукты с поляризационными пластинами, которые работают при 100 ° C и 90% относительной влажности. и самые высокие условия в настоящее время таковы:Высокая температура: 105℃×500HRВлажность и жара: требования к испытаниям ниже 90℃×95% относительной влажности×500ч.Испытание поляризатора на долговечность включает в себя четыре метода испытаний: высокая температура, влажное тепло, низкая температура, а также холод и тепловой удар, из которых наиболее важным испытанием является испытание на влажность и тепло. Испытание на высокую температуру относится к высокотемпературным условиям работы поляризатора при постоянной температуре обжига. В настоящее время по техническому состоянию поляризатор разделяется на:Универсальный тип: рабочая температура 70℃×500HR;Тип средней прочности: рабочая температура 80℃×500HR;Тип с высокой прочностью: рабочая температура на 90℃×500H превышает эти три класса.Поскольку основные материалы поляризационной пленки, пленка ПВА, а также йод и йодид являются легко гидролизуемыми материалами, а также потому, что чувствительный к давлению клей, используемый в поляризационной пластине, также легко портится в условиях высокой температуры и высокой влажности, самые важные вещи в Экологические испытания поляризационной пластины - высокая температура и влажное тепло.
Если вы заинтересованы в нашей продукции и хотите узнать более подробную информацию, пожалуйста, оставьте сообщение здесь, мы ответим вам, как только сможем.
Получить цену
Поддерживается сеть IPv6
