Cooling Mode of Condenser in High and Low Temperature Test Chamber
High and low temperature test chamber is a common temperature test equipment in environmental test equipment, which is suitable for high temperature and low temperature reliability test of industrial products. The working principle of refrigeration in the high and low temperature test chamber is that the refrigerant flows out of the condenser under high pressure, passes through the throttling mechanism (capillary, thermal expansion valve, etc.), reduces its pressure, and then enters the evaporator. When the refrigeration medium enters the evaporator, it is a two-phase mixture (liquid and gas), which evaporates and absorbs heat under low temperature conditions in the evaporator. It then enters the condenser, where heat is released and condensed into a liquid. Xenon lamp aging test chamber uses xenon lamp with long arc as light source, which can provide corresponding environmental simulation and accelerated test for scientific research, product development and quality control. The vehicle environment simulation laboratory can simulate the test environment of engine cold start, vehicle high and low temperature, wind, frost, rain, snow, vehicle emission test, etc.
According to different refrigeration media, the cooling mode of the high and low temperature test chamber condenser can be divided into three types: air cooling, water cooling and liquid nitrogen refrigeration. Their medium is refrigerant, water and liquid nitrogen. Different media correspond to different evaporation temperatures, the same medium under different evaporation pressure, evaporation temperature is not the same.
The different cooling methods of the condenser in the high and low temperature test chamber make the components of the refrigeration different. The air cooling method consists of compressor, various refrigeration accessories, condenser, oil separator and so on. The water cooling method consists of: chiller, cooling tower, freezing pump and auxiliary equipment. Liquid nitrogen is composed of: liquid nitrogen tank, pressure transmitter, pressure gauge, flow meter, level meter, ultra-low temperature solenoid valve and so on.
No matter what kind of cooling method is used in the high and low temperature test chamber condenser, high reliability and safety are the most basic requirements. Instrument test equipment of Lab Companion can provide a variety of condenser cooling methods according to customer needs.
In addition to the high and low temperature test chamber, instrument of Lab Companion also produces all kinds of temperature and humidity test chamber, constant temperature and humidity test equipment, aging chamber (ultraviolet, xenon lamp, ozone aging chamber), thermal shock test chamber, high temperature aging machine and other equipment, all the equipment is produced according to national standards and industry specifications.
High and Low Temperature Test Chamber Requirements Specified in the Standard
The test chamber requirements formulated according to relevant standards should meet the following two points:
1. The temperature and humidity in the high and low temperature test chamber are monitored by the sensor installed in the working space. For the test of the heat dissipation test sample, the installation position of the sensor is formulated in the GB/T2421-1999 standard.
2, The temperature and relative humidity of the working space are required to be constant within the nominal value and its specified tolerance range, and the influence of the test sample should also be considered during the test.
Heat dissipation test sample test:
The volume of the high and low temperature test chamber should be at least 5 times the total volume of the test sample, the distance between the test sample and the internal wall of the test chamber should be selected according to the provisions of GB/T2423.2-2001 Appendix A (standard appendix), the wind speed in the chamber should not exceed 1M/S, and the structure of the mounting frame or support frame of the test chamber sample should simulate the real conditions in use as much as possible. Or otherwise, the effect of the sample mounting rack on the exchange of heat and moisture between the test sample and the surrounding space should be reduced to a minimum, and the relevant specifications may also specify dedicated mounting racks.
Test severity level:
The severity grade of the test chamber consists of the test temperature, relative humidity and test time, and is specified by the relevant specifications. The combination of temperature and relative humidity can be selected from the following values:
a, 30℃±2℃ 93%±3%
b, 30℃±2℃ 85%±3%
c, 40℃±2℃ 93%±3%
d, 40℃±2℃ 85%±3%
During the test, the test chamber shall be at the temperature and humidity of the laboratory, and the test sample at the ambient temperature of the laboratory shall be placed in the normal position or other specified position in the laboratory in an unpacked, unenergized, "ready for use" state, under certain circumstances (e.g. The relevant specifications may allow the test sample to be directly sent into the test chamber under the treated test conditions, but the test sample must be prevented from producing condensation, the temperature in the test chamber should be adjusted to a predetermined severity level, the time should ensure that the test sample reaches temperature stability, the test time should be calculated from the specified conditions, if the relevant specifications require, the test sample can be energized or worked in the conditional test phase, and the relevant specifications should specify the working conditions and working time or cycle of the test sample during the test. At the end of the conditional test, the test sample should still be left in the test chamber and the chamber should be adjusted to the standard atmospheric conditions of the test. The relative humidity should be reduced first, and the time should not exceed 2 hours. The temperature change rate in the test chamber should not exceed 1℃/min on average within 5min, and the relative humidity during temperature regulation should not exceed 75%. After the conditional test, the test sample should enter the recovery procedure.
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.
New Energy Environment Test Solution
The problem of new energy reliability is still difficult, and the integrated detection system of electrical stress and environmental stress will provide the best means for research and development and manufacturing.
Industry
Test object
Use
Technology
Solution
New Energy
Battery (secondary battery)
Inspect
Charge and discharge test
High and low temperature (&humidity) test chamber
Rapid temperature (&humidity)change test chamber
Evaluate
Characteristic test
Rapid temperature (&humidity)change test chamber
Fuel cell
/
Temperature resistance
Small ultra-low temperature test chamber
High and low temperature (&humidity) test chamber
Rapid temperature (&humidity)change test chamber
Smart Watch Reliability Test Conditions
In today's society, elementary school students and even kindergarten children have a smart watch. So, what is a smartwatch? In the late period of sports watch promotion due to the rapid takeoff of smart phones, the smart table has no intention to provide the same PIM effect as PDA and smart phones, and appeals to the smart phone agent assistant accessories, similar to Bluetooth headphones are voice AIDS of smart phones, smart tables become information and data AIDS, providing more convenient and fast information display and operation. There are also other names such as Smart Accessory and Android Remote. Positioned as a mobile phone assistant, the idea is that "the reason why the pocket watch is extinct is because it is simply to look at the time, but also take out the pocket, about 2-3 seconds, but the watch is less than 1 second, which is more convenient than the pocket watch." And after observation, now everyone takes out a smartphone and slides open, just to confirm the message, so that about dozens of times, these confirmation even typing reply do not need, if the dozens of confirmation changed on the watch, you do not always have to pull the machine slide unlock, because this is as time-consuming as a pocket watch. Therefore, after becoming the assistant of the mobile phone, the remote control, if you do not take the mobile phone to go out, the watch is useless in addition to showing the time, and the Bluetooth headset without a mobile phone, almost scrap metal.
Combined with smart bracelet to sell better!!
Smart watch from "smaller than the PDA independent computer" to "smart phone remote control AIDS", seems to have been a more successful positioning, but this CES 2014 can be seen, combined with smart bracelet positioning is better. The smart wristband uses acceleration sensors (and gyroscopes, magnetoresistive sensors, etc.) to sense the user's running speed, step count, etc., and can even detect deep sleep and provide suggestions for exercise and sleep. When the wristband is added to the display, it can display the time and information on the mobile phone. Appeal to mobile phone information, if there is no urgent information needs, in fact, only similar to the Bluetooth headset is regarded as an option (Courier, driver need), if everyone can accept the information access speed of sliding, then the market will be limited. However, in addition to the appeal for exercise and sleep record supervision, and emphasize information tips, rather than emphasizing the remote control of the watch on the mobile phone, it is equivalent to a little sacrifice or almost no sacrifice to the end user, but it brings immediate and new application value (sports, sleep assistance), rather than completely repeating the efficacy value of the mobile phone, which further increases the market success of the smart watch. After constantly adjusting the efficacy, application and positioning, and integrating with the smart ring, we believe that we can have a higher market than in the past.
Smart watch for people and functions:
1. Smart watches for adults
Functions: Bluetooth synchronous mobile phone calls, send and receive text messages, monitor sleep, monitor heart rate, sedentary reminder, running, remote photography, music playback, video, compass and other functions, designed for fashion trend people!
2, Smart watch for the elderly
Functions: ultra-accurate GPS positioning, family calls, emergency calls, heart rate monitoring, sedentary reminders, medicine reminders and other customized functions for the elderly, providing an umbrella for the elderly's travel, bring this watch, refuse to lose the elderly!
3, Children positioning smart watch
Functions: multiple positioning, two-way call, SOS SOS, remote monitoring, intelligent anti-loss, historical track, electronic fence, pedometer, love reward and other functions, to ensure the safety of children, give children a healthy and safe growth environment!
Smart watch specification:
IEC 60086-3: Watch batteries
ISO 105-A02: Colour fastness test -A02 - Grey scale assessment for discoloration
ISO 105-A03-1993: Tests for colour fastness -A03- Grey scale assessment of dyeing
ISO 764: Horological anti-magnetic watches
ISO 1413: Horological shockproof watches
ISO 2281: Horological waterproof watches
ISO 11641-1993: Leather - tests for colour fastness - Colour fastness to perspiration
ISO 14368-3: Impact resistance test of table glass
MIL 810G: Environmental engineering considerations and laboratory testing
QB/T 1897-1993: Waterproof watch inspection
QB/T 1898-1993: Inspection of shockproof watches
QB/T 1908-1993: Key reliability test
QB/T 1919-2012: Type inspection of digital quartz watches with hands and liquid crystal
QB/T 2047-2007: Inspection of metal watchbands
GB/T 2537-2001: leather color fastness test reciprocating grinding color fastness
QB/T 2540-2002: Leather strap inspection
GB/T 6048-1985: digital quartz electronic watch
GB/T 18761-2007: electronic digital display indicator
GB/T 18828-2002: Standard for diving watches
GB/T 22778-2008: LCD digital quartz stopwatch type inspection
GB/T 22780-2008: Type inspection of LCD quartz watches
GB/T 26716-2011 idt ISO 764-2002: Inspection of anti-magnetic watches
HJ216-2005: Eco-Drive watch
Smart watch pilot project:
Reliability, time period measurement accuracy, instantaneous daily difference, operating temperature, voltage range, average temperature coefficient, voltage coefficient, moisture resistance, shock resistance, waterproof performance, battery replacement cycle, key fatigue resistance, light and weather resistance, antistatic performance Ambient temperature range: -25℃ ~ 55℃ Operating temperature: -5 ~ 50℃/80%R.H.(Requirements: each function and liquid crystal display should be complete and normal) High and low working temperature test: 50±1℃/24h→RT/1h→-5±1℃ Temperature change test conditions: (IEC60068-2) High temperature: 30, 40, 55℃ Low temperature: 5, -5, -10, -25℃ Nb residence time (including rising and cooling time) : 10min, 30min, 1hr Nb temperature variability: 3±0.6℃/min, 5±1℃/min.
Wet heat test:
1.40±1℃/85 ~ 95%R.H./24h
2.8±1℃/85 ~ 95%R.H./4h
Warehouse storage humidity test:
40℃/20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%
49℃/10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%
Each step37 hours
Air transport temperature change simulation test:
Specification: IEC60721.2 Electrical and electronic products application environmental conditions - transport national standard
Category: 2K5 (Applicable to the climatic range of unventilated and unpressurized internal transport worldwide)
Temperature range: -65℃←→85℃
RAMP: 5℃/min
Air transport temperature change simulation test:
Specification: IEC60721.6 Electrical and electronic products application environmental conditions - Marine
Category: 6K5 (subject to cold weather, installed in weather-protected but unheated parts)
Temperature range: -25℃←→40℃
RAMP: 3℃/min
Water temperature change resistance test:
5min in 40℃ water → 5min in 20℃ water, 5min in 40℃ water, water depth of 10cm
Water pressure resistance test:
Soak the watch in a container of water, apply an overpressure of 2*10^5Pa[or 20m water depth] within 1 minute, maintain 10 minutes, and then in 1 minute the pressure will be to the standard pressure of the surrounding environment
Salt water resistance test:
Put the watch under test into 30g/L sodium chloride solution at 18 ° C ~ 25 ° C for 24h. Check the case and accessories after the test should not have significant changes; Check the moving parts, especially the rotating front ring should be able to maintain normal function
Underwater reliability test:
The watch under test is immersed in 30cm±2cm of water and placed at a temperature of 18 ° C ~ 25 ° C for 50h, and all mechanical devices should still work normally. During the test, mechanical devices that need to be operated in water, such as time presetting devices and light switches, should be able to work normally; Do condensation test, the inner surface of the table glass shall not appear condensation fog, and the mechanical function should not be damaged
Thermal shock resistance test:
Immerse the watch in water of different temperatures with a depth of 30cm±2cm successively: place it in water of 40 ° C ±2 ° C for 10 minutes; Put in 5℃±2℃ water for 10 minutes; Put in water at 40 ° C ± 2 ° C for 10 minutes (the watch shall not be removed from the water and re-immersed in another water temperature for more than 1 minute). Do condensation test, the inner surface of the table glass shall not appear condensation fog, and should operate normally.
Chemical resistance test:
Citation Specifications: ASTM F 1598-95, ASTM D 1308-87, ASTM D 1308-02
Ingredients: Household chemicals (dirt, dust, oil, fumes and peanut butter, cosmetics, hand cream... Etc.)
Time: 24 hours
Corrosion resistance to artificial sweat test:
QB/T 1901.2-2006 "Gold alloy covers of shell and its accessories - Part 2 Test for purity, thickness, corrosion resistance and adhesion"
Test principle: The artificial sweat is used to contact the object under high temperature (40±2) ℃, and after a long time (not less than 24 hours), the condition of its surface is observed to determine its resistance to sweat corrosion.
Vibration test:
Acceleration (19.6m/s^2), frequency 30Hz ~ 120Hz, scanning cycle 1min
Requirements: The functions and the LCD display should be complete and normal, and the parts should not be loose and fall off
Drop test:
1m drop lithographic hardwood, once watch side, once surface glass
Requirements: Normal function after each impact, no appearance damage [broken glass, case foot bent, case component bent, case broken, button damaged]
Impact test:
Impact cone pad material: polytetrafluoroethylene, impact speed 4.43m/s, impact height 1m
Arm swing test:
2 to 10Hz
Inverter- Reliability Test
Inverter- reliability test also known as voltage converter, its function is to convert DC low voltage into AC high voltage, some electronic equipment must be driven by AC power, but we provide is DC power, at this time you must use the Inverter, direct current into alternating current to drive the electronic parts. Inverter- reliability test also known as voltage converter, its function is to convert DC low voltage into AC high voltage, some electronic equipment must be driven by AC power, but we provide is DC power, at this time you must use the Inverter, direct current into alternating current to drive the electronic parts.
Relevant test conditions:
Item
temperature
time
other
Initial test at normal temperature
25 ℃
TIME≥2 hours
-
Low temperature initial test
0 ℃ or -5 °C
TIME≥2 hours
-
High temperature initial test
60℃
TIME≥2 hours
-
High temperature and high humidity test
40℃/95%RH
240 hours
-
High temperature storage test
70℃
TIME≥96 hours or 240 hours
-
Low temperature storage test -1
-20°C
TIME≥96 hours
-
Low temperature storage test -2
-40℃
240 hours
-
High temperature and high humidity storage test
40℃/90%RH
TIME≥96 hours
-
Temperature cycle test
-20℃~ 70℃
5 cycle
Room temperature ↓-20 ℃(4 hours)↓ Room temperature (90%RH.4 hours)↓70°C(4 hours)↓ Room temperature (4 hours)
High temperature load test
55 ℃
equivalent load, 1,000 hours
-
Life test
40°C
MTBF≥40000 hours
-
on/off test (power cycle)
-
-
1min:on, 1min:off, 5,000 cycles using equivalent load
Vibration test
-
-
Acceleration 3q, frequency 10~55HZ, X, Y, Z three directions 10 minutes each, a total of 30 minutes
Impact test
-
-
Acceleration of 80g, 10 ms each time, Three times in X, Y, Z directions
Note 1: The tested module should be placed at normal (15~35° C,45~65%RH) for one hour before testing
Applicable equipment:
1. High and low temperature test chamber
2. High temperature and high humidity test chamber
3. Rapid temperature cycle test chamber
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