Solution to Thermal Shock Test chamber Refrigeration System Blocking
Thermal shock test chamber is generally composed of compressor, air conditioning evaporator, cooler and pipe system software. Refrigeration system blockage generally has two kinds of dirty blockage and ice blockage, and oil blockage is relatively rare.
1. Dirty and blocked
When the compressor of thermal shock test chamber is damaged, and there is waste in the refrigeration system, this waste is very easy to block in the capillary or filter device, which is called dirty plugging. Dirty blockage is because there is residue in the refrigeration system (oxygenated skin, copper chips, welding through), when it is circulated with the refrigerant system, it causes blockage at the capillary or filter device.
Dirty blockage removal method: remove the capillary tube, filter device, cooler, air conditioning evaporator with gas cutting, disassemble the carbon molecular sieve in the capillary tube and filter device, clean the cooler and air conditioning evaporator, carry out dry, vacuum packaging, welding, and fill with refrigerant.
2. Ice jam
Ice blockage is caused by water entering the refrigeration system of thermal shock test chamber. Due to its own with a certain amount of moisture, coupled with the maintenance or refrigerant in the whole process of taking time processing regulations are not tight, so that water and gas into the system software. Under the ultra-high pressure effect of the compressor, the refrigerant is changed from a liquid to a vapor state, so that the water is passed into the narrow and long capillary tubes with the refrigerant circulation system. When the moisture content of each kilogram of refrigerant exceeds 20mg, the filter device is saturated with water, and the water can not be filtered out. When the temperature of the capillary inlet and outlet is 0 ° C, the water is converted from the refrigerant and becomes ice, resulting in ice blocking.
Dirty blocking and ice blocking are divided into full and half blocked, the common fault condition is that the air conditioning evaporator is not frosting or frosting is not full, the temperature behind the cooler is high, and the hand drying filter or capillary entrance feels that the temperature is basically the same as the indoor temperature, sometimes less than the indoor temperature, and a lot of steam is sprayed out of the cutting process pipe. After the ice jam occurs, the friction resistance of the compressor exhaust pipe increases, resulting in the compressor overtemperature, the overload protector is working, and the compressor stops running. After about 25 minutes, a part of the ice jam melts, the compressor temperature decreases, the contact point of the temperature controller and the overload protector is closed, and the compressor starts the refrigerator. Therefore, the ice blockage has regularity, and the air conditioning evaporator can see regular frosting and defrosting conditions.
How to Change the Refrigerant Oil of Thermal Shock Test Chamber?
Thermal shock test chamber is a necessary test equipment for metal, plastic, rubber, electronics and other material industries, used to test material structure or composite materials, in an instant under the continuous environment of extremely high temperature and extremely low temperature to endure the degree of chemical changes or physical damage caused by thermal expansion and contraction of the sample in the shortest time. Thermal shock test chamberr meets the test method: GB/T2423.1.2, GB/T10592-2008, GJB150.3 thermal shock test.
In thermal shock test chamber, if the compressor is semi-closed piston compressor in operation for 500 hours, it is necessary to observe the oil temperature and oil pressure changes of the frozen oil, and if the frozen oil is discolored, it must be replaced. After the initial operation of the compressor unit for 2000 hours, the cumulative operation of three years or the operation time of more than 10,000 to 12,000 hours should be maintained within a time limit and the chilled oil should be replaced.
The refrigerated oil replacement of the semi-closed piston compressor in thermal shock test chamber can be performed according to the following steps:
1, Close high pressure exhaust and low pressure suction stop valve of thermal shock test chamber, and then screw down the oil plug, the oil plug is generally in the bottom of the crankcase, and then put the frozen oil clean and clean the filter.
2, Use the low-pressure impact gas valve needle to blow nitrogen into the oil port and then use the pressure to discharge the residual oil in the body, install a clean filter and tighten the oil plug.
3. Connect the low pressure tube filled with fluorine gauge to the low pressure process valve needle with a vacuum pump to pump the crankcase into negative pressure, and then remove the other fluorine tube separately, put one end into the chilled oil, and put the other end on the valve needle of the low pressure suction of the oil pump. The chilled oil is sucked into the crankcase due to the negative pressure, and add it to the position slightly higher than the lower limit of the oil mirror line.
4. After injection, tighten the process column or remove the fluorine filling tube, and then connect the fluorine pressure gauge to vacuum the compressor.
5. After vacuuming, it is necessary to open the high and low pressure stop valve of the compressor to check whether the refrigerant has leaked.
6, Open thermal shock test chamber unit to check the lubrication of the compressor and the oil level of the oil mirror, the oil level can not be less than a quarter of the mirror.
The above is how to replace the refrigerant oil of the semi-closed piston compressor in thermal shock test chamber. Because the refrigerant oil has hygroscope, the replacement process needs to reduce the air entering the system and the oil storage container. If the cold aging oil is injected too much, there is the risk of liquid shock.
The Significance of Constructing ISO27001 Information Security Management System
After the rapid development of computer technology, network technology has been applied in a full range, and the ensuing information security problem has gradually received the attention of all sectors of society. Information security has not only been fully developed in the field of communication and data, but also involved in computer security, communication security and network security. To establish an information security system that conforms to modern enterprise business and management, improve information construction, and reduce security loopholes through the IS027001 information security management system is of great significance to the long-term development of enterprises.
The benefits of constructing IS027001 Information Security management system：
(1) It can effectively protect information resources and promote the orderly, healthy and sustainable development of informatization process. IS027001 is a standard system in the field of information security management, similar to the quality management system certification IS09000 standard.
(2) When the enterprise passes the IS027001 certification, it is equivalent to the enterprise's information security management is scientific and reasonable, and can effectively protect customer information and internal information. After the IS027001 Information security management system certification, you can have a number of benefits or advantages. The introduction of information security management system can coordinate information management at all levels, simplify management links and improve management efficiency.
(3) Through the IS027001 information security management system certification, it can also increase the credit degree of e-commerce exchanges between enterprises, establish a trusted cooperative relationship between the website and trading partners, and deepen the development of enterprise business information.
(4) Through the IS027001 information security management system certification, it can promote the relevant enterprises to achieve information security commitments, eliminate the distrust of customers and employees, and improve business performance. In addition, it can even gain international recognition so that the business can expand overseas.
The significance of constructing IS027001 information security management system：
In essence, information security management system is an information security management mode, its purpose is to improve the management level of enterprises, promote the benign development of enterprises, ensure the security of various information resources of enterprises, and not be stolen by the outside world to cause negative impact on enterprises. Information security management system with many standards, the main reference is IS027001 information security management standard. To achieve enterprise information security management standardized and orderly through the reference of the standard, so that enterprise information security management can be more scientific and reasonable. Information security management develops with the development of information technology. In the information society, information resources have become a precious resource and has high economic value.
Under the realistic background of information security problems, strengthening the construction of information security management system has extremely important practical role and future significance. Under the IS027001 information security standard, we develop advanced technologies, carefully evaluate information security risks, and build an information security management system that conforms to the current situation and future development of enterprises.
What is Environmental Testing?
The electronic devices and industrial products we rely on every day are affected by the environment in many ways, including temperature, humidity, pressure, light, electromagnetic waves and vibration. Environmental testing analyzes and evaluates the impact of these environmental factors on the product to determine its durability and reliability.
Guangdong Lab Companion LTD., has 10 million yuan registered capital and 3 R & D manufacturing plants in Dongguan, Kunshan and Chongqing. Lab Companion has been specialized in high and low temperature test equipment technology for 19 years, operating according to ISO9001, ISO14001, ISO 45001, ISO27001 four systems, setting sales and maintenance service centers in Shanghai, Wuhan, Chengdu, Chongqing, Xi 'an and Hong Kong. We work closely with International Organization of Leg al Metrology, Chinese Academy of Sciences, State Grid, China Southern Power Grid, Tsinghua University, Peking University, Hong Kong University of Science and Technology and other research institutions.
Main products of Lab Companion includes high and low temperature test chamber, constant temperature and humidity test chamber, rapid temperature cycling test chamber, thermal shock test chamber, high and low temperature and low pressure test chamber, vibration of the comprehensive chamber, industrial oven, vacuum oven, nitrogen oven, etc, providing high quality experimental equipment for universities, research institutes, medical health, inspection and quarantine, environmental monitoring, food and drugs, automobile manufacturing, petrochemical, rubber and plastic products, IC semiconductor, IT manufacturing and other fields.
Thermal Cycling Test(TC) & Thermal Shock Test(TS)
Thermal Cycling Test(TC):
In the life cycle of the product, it may face various environmental conditions, which makes the product appear in the vulnerable part, resulting in product damage or failure, and then affect the reliability of the product.
A series of high and low temperature cycling tests are done on the temperature change at the temperature variation rate of 5~15 degrees per minute, which is not a real simulation of the actual situation. Its purpose is to apply stress to the test piece, accelerate the aging factor of the test piece, so that the test piece may cause damage to the system equipment and components under environmental factors, in order to determine whether the test piece is correctly designed or manufactured.
Common ones are:
Electrical function of the product
The lubricant deteriorates and loses lubrication
Loss of mechanical strength, resulting in cracks and cracks
The deterioration of the material causes chemical action
Scope of application:
Module/system product environment simulation test
Module/System Product Strife test
PCB/PCBA/ Solder Joint Accelerated Stress Test (ALT/AST)...
Thermal Shock Test(TS):
In the life cycle of the product, it may face various environmental conditions, which makes the product appear in the vulnerable part, resulting in product damage or failure, and then affect the reliability of the product.
High and low temperature shock tests under extremely harsh conditions on rapid temperature changes at a temperature variability of 40 degrees per minute are not truly simulated. Its purpose is to apply severe stress to the test piece to accelerate the aging factor of the test piece, so that the test piece may cause potential damage to the system equipment and components under environmental factors, in order to determine whether the test piece is correctly designed or manufactured.
Common ones are:
Electrical function of the product
The product structure is damaged or the strength is reduced
Tin cracking of components
The deterioration of the material causes chemical action
Seal damage
Machine specifications:
Temperature range: -60 ° C to +150 ° C
Recovery time: < 5 minutes
Inside dimension: 370*350*330mm (D×W×H)
Scope of application:
PCB reliability acceleration test
Accelerated life test of vehicle electric module
LED parts accelerated test...
Effects of temperature changes on products:
The coating layer of components falls off, the potting materials and sealing compounds crack, even the sealing shell cracks, and the filling materials leak, which causes the electrical performance of components to decline.
Products composed of different materials, when the temperature changes, the product is not evenly heated, resulting in product deformation, sealing products cracking, glass or glassware and optics broken;
The large temperature difference makes the surface of the product condense or frost at low temperature, evaporates or melts at high temperature, and the result of such repeated action leads to and accelerates the corrosion of the product.
Environmental effects of temperature change:
Broken glass and optical equipment.
The movable part is stuck or loose.
Structure creates separation.
Electrical changes.
Electrical or mechanical failure due to rapid condensation or freezing.
Fracture in a granular or striated manner.
Different shrinkage or expansion characteristics of different materials.
The component is deformed or broken.
Cracks in surface coatings.
Air leak in the containment compartment.
The Relationship Between the Altitude of the Standard Atmosphere and Air Temperature and Pressure
The standard atmosphere referred to here refers to the "1964, ICAO Standard atmosphere" adopted by the International Civil Aviation Organization. Below an altitude of 32 km, it is the same as "1976, U.S. standard atmosphere". Changes in air temperature near the surface (below 32 km) are:
Ground: The air temperature is 15.0℃, the air pressure P=1013.25mb= 0.101325MPa
Temperature change rate from ground to elevation 11 km: -6.5 ℃/ km
On the 11km interface:
The air temperature is -56.5 ℃ and the air pressure P=226.32mb
Temperature change rate at elevations of 11-20 km: 0.0℃/ km
Temperature change rate at altitude 20-32 km: +1.0/ km
The following table lists the temperature and pressure values of the standard atmosphere at different altitudes. In the table, "gpm" is the altitude meter, and its negative sign represents the altitude
Gpm
Temperature℃
Atmospheric pressure(mb)
Gpm
Temperature℃
Atmospheric pressure(mb)
Gpm
Temperature℃
Atmospheric pressure(mb)
-400
17.6
1062.2
4800
-16.2
554.8
10000
-50.0
264.4
-200
16.3
1037.5
5000
-17.5
540.2
10200
-51.3
256.4
0
15.0
1013.3
5200
-18.8
525.9
10400
-52.6
248.6
200
13.7
989.5
5400
-20.1
511.9
10600
-53.9
241.0
400
12.4
966.1
5600
-21.4
498.3
10800
-55.2
233.6
600
11.1
943.2
5800
-22.7
484.9
11000
-56.5
226.3
800
9.8
920.8
6000
-24.0
471.8
11500
-56.5
209.2
1000
8.5
898.7
6200
-25.3
459.0
12000
-56.5
193.3
1200
7.2
877.2
6400
-26.6
446.5
12500
-56.5
178.7
1400
5.9
856.0
6600
-27.9
434.3
13000
-56.5
165.1
1600
4.6
835.2
6800
-29.2
422.3
13500
-56.5
152.6
1800
3.3
814.9
7000
-30.5
410.6
14000
-56.5
141.0
2000
2.0
795.0
7200
-31.8
399.2
14500
-56.5
130.3
2200
0.7
775.4
7400
-33.1
388.0
15000
-56.5
120.5
2400
-0.6
756.3
7600
-34.4
377.1
15500
-56.5
111.3
2600
-1.9
737.5
7800
-35.7
366.4
16000
-56.5
102.9
2800
-3.2
719.1
8000
-37.0
356.0
17000
-56.5
87.9
3000
-4.5
701.1
8200
-38.3
345.8
18000
-56.5
75.0
3200
-5.8
683.4
8400
-39.6
335.9
19000
-56.5
64.1
3400
-7.1
666.2
8600
-40.9
326.2
20000
-56.5
54.7
3600
-8.4
649.2
8800
-42.2
316.7
22000
-54.5
40.0
3800
-9.7
632.6
9000
-43.5
307.4
24000
-52.5
29.3
4000
-11.0
616.4
9200
-44.8
298.4
26000
-50.5
21.5
4200
-12.3
600.5
9400
-46.1
289.6
28000
-48.5
15.9
4400
-13.6
584.9
9600
-47.4
281.0
30000
-46.5
11.7
4600
-14.9
569.7
9800
-48.7
272.6
32000
-44.5
8.7
Unit conversion relation
1mbar=100Pa=0.1KPa=0.0001 Mpa
1ft=0.3048m=304.8mm
55000ft*0.3048=16764m
Lab Companion focused on the production of reliability environmental test equipment for 19 years, successfully helped 18,000 enterprises to test the reliability and environmental performance of products and materials.
The main products are: high temperature test chamber, high and low temperature and humidity test chamber, walk-in environmental test chamber, rapid temperature cycling test chamber, thermal shock test chamber, high and low temperature low pressure test chamber, vibration of the comprehensive chamber and other test equipment manufacturing solutions to help enterprises R & D bigger and stronger!
If you need to know more about the products of the environmental test chamber, you can search the official website of "Lab Companion", feel free to contact us for consultation, we can provide you with one-on-one professional technical advice and guidance.
Tablet Reliability Test
A Tablet Computer, also known as a Tablet Personal Computer (Tablet PC), is a small, portable personal computer that uses a touch screen as its basic input device. It is an electronic product with strong mobility, and it can be seen everywhere in life (such as waiting stations, trains, high-speed trains, cafes, restaurants, meeting rooms, suburbs, etc.). People carry only simple coat protection or even no, in order to facilitate use, the design reduces the size, so that it can be directly placed in the pocket or handbag, backpack, but the tablet computer in the process of moving will also experience many environmental physical changes (such as temperature, humidity, vibration, impact, extrusion, etc.). Etc.) and natural damage (such as ultraviolet light, sunlight, dust, salt spray, water droplets... It will also cause artificial unintentional injury or abnormal operation and misoperation, and even cause failure and damage (such as: household chemicals, hand sweating, falling, terminal insertion and removal too much, pocket friction, crystal nails... These will shorten the life of the tablet computer, in order to ensure the reliability of the product and extend the service life to improve, we must carry out a number of environmental reliability test projects on the tablet computer, the following relevant tests for your reference.
Environmental test project description:
Simulate various harsh environments and reliability assessments used by tablet computers to test whether their performance meets the requirements; It mainly includes high and low temperature operation and high and low temperature storage, temperature and condensation, temperature cycle and shock, wet and heat combination test, ultraviolet, sunlight, drip, dust, salt spray and other tests.
Operating temperature range: 0℃ ~ 35℃/5% ~ 95%RH
Storage temperature range: -10℃ ~ 50℃/10% ~ 90%RH
Operating low temperature test: -10℃/2h/ power operation
Operating high temperature test: 40℃/8h/ all running
Storage low temperature test: -20℃/96h/ shutdown
Storage high temperature test: 60℃/96h/ shutdown
High temperature test of vehicle storage: 85℃/96h/ shutdown
Temperature shock: -40℃(30min)←→80℃(30min)/10cycle
Wet heat test: 40℃/95%R.H./48h/ power standby
Hot and humid cycle test: 40℃/95%R.H./1h→ramp:1℃/min→-10℃/1h, 20cycles, power standby
Wet heat test: 40℃/95%R.H./48h/ power standby
Hot and humid cycle test: 40℃/95%R.H./1h→ramp:1℃/min→-10℃/1h, 20cycles, power standby
Weather resistance test:
Simulation of the most severe natural conditions, solar thermal effect test, each cycle of 24 hours, 8 hours of continuous exposure, 16 hours to keep dark, each cycle radiation amount of 8.96 kWh/m2, a total of 10cycles.
Salt spray test:
5% sodium chloride solution/Water temperature 35°C/PH 6.5~7.2/24h/ Shutdown → Pure water wipe shell →55°C/0.5h→ Function test: after 2 hours, after 40/80%R.H./168h.
Dripping test: According to IEC60529, in line with IPX2 waterproof rating, can prevent water droplets falling at an Angle of less than 15 degrees from entering the tablet computer and causing damage. Test conditions: water flow rate 3mm/min, 2.5min at each position, checkpoint: after test, 24 hours later, standby for 1 week.
Dust Test:
According to IEC60529, in line with the IP5X dust class, can not completely prevent the entry of dust but does not affect the device should be the action and anquan, in addition to tablet computers are currently many personal mobile portable 3C products commonly used dust standards, such as: mobile phones, digital cameras, MP3, MP4... Let's wait.
Conditions:
Dust sample 110mm/3 ~ 8h/ test for dynamic operation
After the test, a microscope is used to detect whether dust particles will enter the interior space of the tablet.
Chemical staining test:
Confirm the external components related to the tablet, confirm the chemical resistance of household chemicals, chemicals: sunscreen, lipstick, hand cream, mosquito repellent, cooking oil (salad oil, sunflower oil, olive oil... Etc.), the test time is 24 hours, check the color, gloss, surface smoothness... Etc., and confirm whether there are bubbles or cracks.
Mechanical test:
Test the strength of the mechanical structure of the tablet computer and the wear resistance of the key components; Mainly includes vibration test, drop test, impact test, plug test, and wear test... Etc.
Fall test: The height of 130cm, free fall on the smooth soil surface, each side fell 7 times, 2 sides a total of 14 times, tablet computer in standby state, each fall, the function of the test product is checked.
Repeated drop test: the height of 30cm, free drop on the smooth dense surface of 2cm thickness, each side fell 100 times, each interval of 2s, 7 sides a total of 700 times, every 20 times, check the function of the experimental product, tablet computer is in the state of power.
Random vibration test: frequency 30 ~ 100Hz, 2G, axial: three axial. Time: 1 hour in each direction, for a total of three hours, the tablet is in standby mode.
Screen impact resistance test: 11φ/5.5g copper ball fell on the center surface of 1m object at 1.8m height and 3ψ/9g stainless steel ball fell at 30cm height
Screen writing durability: more than 100,000 words (width R0.8mm, pressure 250g)
Screen touch durability: 1 million, 10 million, 160 million, 200 million times or more (width R8mm, hardness 60°, pressure 250g, 2 times per second)
Screen flat press test: the diameter of the rubber block is 8mm, the pressure speed is 1.2mm/min, the vertical direction is 5kg force flat press the window 3 times, each time for 5 seconds, the screen should display normally.
Screen front flat press test: The entire contact area, the direction of the vertical 25kg force front flat press each side of the tablet computer, for 10 seconds, flat press 3 times, there should be no abnormal.
Earphone plug and remove test: Insert the earphone vertically into the earphone hole, and then pull it out vertically. Repeat this for more than 5000 times
I/O plug and pull test: The tablet is in standby state, and the plug terminal connector is pulled out, a total of more than 5000 times
Pocket friction test: Simulate various materials pocket or backpack, the tablet is repeatedly rubbed in the pocket 2,000 times (friction test will also add some mixed dust particles, including dust particles, yan grass particles, fluff and paper particles for mixing test).
Screen hardness test: hardness greater than class 7 (ASTM D 3363, JIS 5400)
Screen impact test: hit the most vulnerable sides and center of the panel with a force of more than 5㎏
Laptop Test Conditions
Notebook computer from the early 12-inch screen evolution to the current LED backlit screen, its computing efficiency and 3D processing, will not be lost to the general desktop computer, and the weight is becoming less and less burden, the relative reliability test requirements for the entire notebook computer is becoming more and more stringent, from the early packaging to the current boot down, the traditional high temperature and high humidity to the current condensation test. From the temperature and humidity range of the general environment to the desert test as a common condition, these are the parts that need to be considered in the production of notebook computer related components and design, the test conditions of the relevant environmental tests collected so far are organized and shared with you.
Keyboard tapping test:
Test one:
GB:1 million times
Key pressure :0.3~0.8(N)
Button stroke :0.3~1.5(mm)
Test 2: Key pressure: 75g(±10g) Test 10 keys for 14 days, 240 times per minute, a total of about 4.83 million times, once every 1 million times
Japanese manufacturers :2 to 5 million times
Taiwan manufacturer 1: more than 8 million times
Taiwan Manufacturer 2:10 million times
Power switch and connector plug pull test:
This test model simulates the lateral forces that each connector can withstand under abnormal usage. General laptop test items: USB, 1394, PS2, RJ45, Modem, VGA... Equal application force 5kg(50 times), up and down left and right pull and plug.
Power switch and connector plug test:
4000 times (Power supply)
Screen cover opening and closing test:
Taiwanese manufacturers: open and close 20,000 times
Japanese manufacturer 1: opening and closing test 85,000 times
Japanese manufacturer 2: opening and closing 30,000 times
System standby and recovery switch test:
General note type: interval 10sec, 1000cycles
Japanese manufacturer: System standby and recovery switch test 2000 times
Common causes of laptop failure:
☆ Foreign objects fall on the notebook
☆ Falls off the table while in use
☆ Tuck the notebook in a handbag or trolley case
☆ Extremely high temperature or low temperature ☆ Normal use (overuse)
☆ Wrong use in tourist destinations
☆PCMCIA inserted incorrectly
☆ Place foreign objects on the keyboard
Shutdown drop test:
General notebook type :76 cm
GB package drop: 100cm
Us Army and Japanese notebook computers: The height of the computer is 90 cm from all sides, sides, corners, a total of 26 sides
Platform :74 cm (packing required)
Land: 90cm (packing required)
TOSHIBA&BENQ 100 cm
Boot drop test:
Japanese :10 cm boot fall
Taiwan :74 cm boot fall
Laptop main board temperature shock:
Slope 20℃/min
Number of cycles 50cycles(no operation during impact)
The U.S. military's technical standards and test conditions for laptop procurement are as follows:
Impact test: Drop the computer 26 times from all sides, sides and corners at a height of 90 cm
Earthquake resistance test :20Hz~1000Hz, 1000Hz~2000Hz frequency once an hour X, Y and Z axis continuous vibration
Temperature test :0℃~60℃ 72 hours of aging oven
Waterproof test: Spray water on the computer for 10 minutes in all directions, and the water spray rate is 1mm per minute
Dust test: Spray the concentration of 60,000 mg/ per cubic meter of dust for 2 seconds (interval of 10 minutes, 10 consecutive times, time 1 hour)
Meets MIL-STD-810 military specifications
Waterproof test:
Us Army notebook :protection class:IP54(dust & rain) Sprayed the computer with water in all directions for 10 minutes at a rate of 1mm per minute.
Dust proof test:
Us Army notebook: Spray a concentration of 60,000 mg/ m3 of dust for 2 seconds (10 minute intervals, 10 consecutive times, time 1 hour)
Concentrator Solar Cell
A concentrating solar cell is a combination of [Concentrator Photovoltaic]+[Fresnel Lenes]+[Sun Tracker]. Its solar energy conversion efficiency can reach 31% ~ 40.7%, although the conversion efficiency is high, but due to the long sunward time, it has been used in the space industry in the past, and now it can be used in the power generation industry with sunlight tracker, which is not suitable for general families. The main material of concentrating solar cells is gallium arsenide (GaAs), that is, the three five group (III-V) materials. General silicon crystal materials can only absorb the energy of 400 ~ 1,100nm wavelength in the solar spectrum, and the concentrator is different from silicon wafer solar technology, through the multi-junction compound semiconductor can absorb a wider range of solar spectrum energy, and the current development of three-junction InGaP/GaAs/Ge concentrator solar cells can greatly improve the conversion efficiency. The three-junction concentrating solar cell can absorb energy of 300 ~ 1900nm wavelength relative to its conversion efficiency can be greatly improved, and the heat resistance of concentrating solar cells is higher than that of general wafer-type solar cells.
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
Reliability Environmental Test Equipment Combined with Multi-track Temperature Control and Detection Applications
Environmental test equipment includes constant temperature and humidity test chamber, hot and cold shock test chamber, temperature cycle test chamber, no wind oven... These test equipment are all in the simulated environment of temperature, humidity impact on the product, to find out the design, production, storage, transportation, use process may appear product defects, previously only simulated test area air temperature, but in the new international standards and the new test conditions of the international factory, the beginning of the requirements based on the air temperature is not. It is the surface temperature of the test product. In addition, the surface temperature should also be measured and recorded synchronously during the test process for post-test analysis. The relevant environmental test equipment should be combined with surface temperature control and the application of surface temperature measurement is summarized as follows.
Constant temperature and humidity test chamber test table temperature detection application:
Description: Constant temperature and humidity test chamber in the test process, combined with multi-track temperature detection, high temperature and humidity, condensation (condensation), combined temperature and humidity, slow temperature cycle... During the test process, the sensor is affixed to the surface of the test product, which can be used to measure the surface temperature or internal temperature of the test product. Through this multi-track temperature detection module, the set conditions, actual temperature and humidity, the surface temperature of the test product, and the same measurement and record can be integrated into a synchronous curve file for subsequent storage and analysis.
Thermal shock test chamber surface temperature control and detection applications: [dwell time based on surface temperature control], [temperature shock process surface temperature measurement record]
Description: The 8-rail temperature sensor is attached to the surface of the test product and applied to the temperature shock process. The dwell time can be counted backward according to the arrival of the surface temperature. During the impact process, the setting conditions, the test temperature, the surface temperature of the test product, and the same measurement and record can be integrated into a synchronous curve.
Temperature cycle test chamber surface temperature control and detection application: [Temperature cycle temperature variability and dwell time are controlled according to the test product surface temperature]
Description: Temperature cycle test is different from temperature shock test. Temperature shock test uses the maximum energy of the system to carry out temperature changes between high and low temperatures, and its temperature change rate is as high as 30 ~ 40℃ /min. Temperature cycle test requires a process of high and low temperature changes, and its temperature variability can be set and controlled. However, the new specification and the test conditions of international manufacturers have begun to require that the temperature variability refers to the surface temperature of the test product, not the air temperature, and the current temperature cycle specification temperature variability control. According to the test product surface specifications are [JEDEC-22A-104F, IEC60749-25, IPC9701, ISO16750, AEC-Q100, LV124, GMW3172]... In addition, the residence time of high and low temperatures can also be based on the test surface, rather than the air temperature.
Temperature cyclic stress screening test chamber surface temperature control and detection applications:
Instructions: Temperature cycle stress screening testing machine, combined with multi-rail temperature measurement, in the temperature variability of stress screening, you can choose to use [air temperature] or [test product surface temperature] to control the temperature variability, in addition, in the high and low temperature resident process, the time reciprocal can also be controlled according to the surface of the test product. In accordance with the relevant specifications (GJB1032, IEST) and the requirements of international organizations, according to the definition of GJB1032 in the stress screening residence time and temperature measurement point, 1. The number of thermocouples fixed on the product shall not be less than 3, and the temperature measurement point of the cooling system shall not be less than 6, 2. Ensure that the temperature of 2/3 thermocouples on the product is set at ±10℃, in addition, according to the requirements of IEST(International Association for Environmental Science and Technology), the residence time should reach the temperature stabilization time plus 5min or performance test time.
No air oven (natural convection test chamber) surface temperature detection application:
Description: Through the combination of a windless oven (natural convection test chamber) and a multi-track temperature detection module, the temperature environment without fan (natural convection) is generated, and the relevant temperature detection test is integrated. This solution can be applied to the actual ambient temperature test of electronic products (such as: Cloud server, 5G, electric vehicle interior, indoor without air conditioning environment, solar inverter, large LCD TV, home Internet sharer, office 3C, laptop, desktop, game console....... Etc.).
Purpose of Temperature Shock Test
Reliability environmental test In addition to high Temperature, low temperature, high temperature and high humidity, temperature and humidity combined cycle, temperature Shock (cold and hot Shock) is also a common test project, temperature shock Testing (Thermal Shock Testing, Temperature Shock Testing, referred to as: TST), the purpose of the temperature shock test is to find out the design and process defects of the product through the severe temperature changes that exceed the natural environment [temperature variability greater than 20℃/min, and even up to 30 ~ 40℃/min], but there is often a situation where the temperature cycle is confused with the temperature shock. "Temperature cycle" means that in the process of high and low temperature change, the temperature change rate is specified and controlled; The temperature change rate of "temperature shock" (hot and cold shock) is not specified (Ramp Time), mainly requires Recovery Time, according to the IEC specification, there are three kinds of temperature cycle test methods [Na, Nb, NC]. Thermal shock is one of the three [Na] test items [rapid temperature change with specified conversion time; medium: air], the main parameters of temperature shock (thermal shock) are: High temperature and low temperature conditions, residence time, return time, number of cycles, in high and low temperature conditions and residence time the current new specification will be based on the surface temperature of the test product, rather than the air temperature in the test area of the test equipment.
Thermal shock test chamber:
It is used to test the material structure or composite material, in an instant under the continuous environment of extremely high temperature and extremely low temperature, the degree of tolerance, so as to test the chemical changes or physical damage caused by thermal expansion and contraction in the shortest time, the applicable objects include metal, plastic, rubber, electronic.... Such materials can be used as the basis or reference for the improvement of its products.
The cold and thermal shock (temperature shock) test process can identify the following product defects:
Different expansion coefficient caused by the stripping of the joint
Water enters after cracking with different expansion coefficient
Accelerated test for corrosion and short circuit caused by water infiltration
According to the international standard IEC, the following conditions are common temperature changes:
1. When the equipment is transferred from a warm indoor environment to a cold outdoor environment, or vice versa
2. When the equipment is suddenly cooled by rain or cold water
3. Installed in the outside airborne equipment (such as: automobile, 5G, outdoor monitoring system, solar energy)
4. Under certain transport [car, ship, air] and storage conditions [non-air-conditioned warehouse]
Temperature impact can be divided into two types of two-box impact and three-box impact:
Instructions: Temperature impact is common [high temperature → low temperature, low temperature → high temperature] way, this way is also called [two-box impact], another so-called [three-box impact], the process is [high temperature → normal temperature → low temperature, low temperature → normal temperature → high temperature], inserted between the high temperature and low temperature, to avoid adding a buffer between the two extreme temperatures. If you look at the specifications and test conditions, there is usually a normal temperature condition, the high and low temperature will be extremely high and very low, in the military specifications and vehicle regulations will see that there is a normal temperature impact condition.
IEC temperature shock test conditions:
High temperature: 30, 40, 55, 70, 85, 100, 125, 155℃
Low temperature: 5, -5, -10, -25, -40, -55, -65℃
Residence time: 10min, 30min, 1hr, 2hr, 3hr(if not specified, 3hr)
Temperature shock residence time description:
The Dwell Time of temperature shock in addition to the requirements of the specification, some will depend on the weight of the test product and the surface temperature of the test product
The specifications of the thermal shock residence time according to weight are:
GJB360A-96-107, MIL-202F-107, EIAJ ED4701/100, JASO-D001... Let's wait.
The thermal shock residence time is based on the surface temperature control specifications: MIL-STD-883K, MIL-STD-202H(air above the test object)
MIL883K-2016 requirements for [temperature shock] specification:
1. After the air temperature reaches the set value, the surface of the test product needs to arrive within 16 minutes (residence time is not less than 10min).
2. High temperature and low temperature impact are more than the set value, but not more than 10℃.
Follow-up action of IEC temperature shock test
Reason: The IEC temperature test method is best considered as part of a series of tests, because some failures may not be immediately apparent after the test method is completed.
Follow-up test items:
IEC60068-2-17 Tightness test
IEC60068-2-6 Sinusoidal vibration
IEC60068-2-78 Steady Humid heat
IEC60068-2-30 Hot and humid temperature cycle
Tin whisker (whisker) temperature impact test conditions finishing:
1. - 55 (+ 0 / -) 10 ℃ please - 85 (+ / - 0) 10 ℃, 20 min / 1 cycle (500 cycle check again)
1000 cycles, 1500 cycles, 2000 cycles, 3000 cycles
2. 85(±5)℃←→-40(+5/-15)℃, 20min/1cycle, 500cycles
3.-35±5℃←→125±5℃, dwell for 7min, 500±4cycles
4. - 55 (+ 0 / -) 10 ℃ please - 80 (+ / - 0) 10 ℃, 7 min reside, 20 min / 1 cycle, 1000 cycles
Thermal shock testing machine product features:
Defrosting frequency: defrosting every 600cycles [Test condition: +150℃ ~ -55℃]
Load adjustment function: The system can automatically adjust according to the load of the product to be tested, without manual setting
High weight load: Before the equipment leaves the factory, use aluminum IC(7.5Kg) for load simulation to confirm that the equipment can meet the demand
Temperature shock Sensor location: The air outlet and return air outlet in the test area can be selected or both can be installed, which conforms to the MIL-STD test specification. In addition to meeting the requirements of the specification, it is also closer to the impact effect of the test product during the test, reducing the test uncertainty and distribution uniformity.
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