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Types of Test Chamber Cooling System

Types of Test Chamber Cooling SystemThere are two major types of chamber cooling systems, expendable refrigerants and mechanically cooled.Expendable RefrigerantsExpendable refrigerants are liquid/gases that can be injected directly into the space being cooled or into heatexchangers, similar to mechanical systems. As the liquid enters the chamber (directly or through a fin coil) itabsorbs heat and flashes to a gas. The gas is then vented out of the chamber and should be ducted outdoors.The two most popular refrigerants are liquid nitrogen (LN2) and liquid carbon dioxide (CO2). Cryogenictemperatures down to - 184˚C can be achieved with LN2. CO2 on the other hand can only achievetemperature down to -68˚C. Both of these gases are environmental safe andcan be vented to the atmosphere. Note: it is imperative that the gases be ventedoutdoors. These gases displace oxygen and asphyxia can occur if the chamber is notproperly vented.Mechanically cooledMechanically-cooled refrigeration systems are fundamentally the same as those usedin home refrigerators. They utilize a compressor and circulate a refrigerant around aclosed loop system. The ultimate low temperature required by your testingdetermines the type of refrigeration system needed.Single StageSingle-stage refrigeration systems typically can pull the temperature in the chamber down to - 34˚C.Some manufacturers rate their single stage systems down to -40˚C. However, due to the refrigerant usedthere is very little cooling capacity available at -40˚C and can be difficult to achieve. For continuous operation at-40˚C and below most manufacturers recommend a cascade refrigeration system.CascadeCascade refrigeration systems have two separate refrigeration systems working to cool the chamber down to anultimate low of -73˚C and -85˚C on industrial freezer models. The first stage refrigeration system coolsand condenses the refrigerant in the second stage. The second stage refrigerant flows through an evaporatorlocated in the chamber which cools the air. These systems can become very complex depending on yourapplication.

Tell The Manufacturer Your Test Specimen Type

Tell The Manufacturer Your Test Specimen Type1.It is important to inform the chamber manufacturer of the type of product being test in the chamber. However, if all the details are not given to the chamber manufacturer, the resulting selection may not be best for your application and could cause safety risks.  2.The chamber manufacturer should understand your test objectives as well as you do. The more information he has regarding your product and your test requirements, the better equipped he will be in either selecting a standard product to meet your needs or proposing a custom chamber designed to meet the special requirements of your product testing.  3.For example, hydraulic valves under pressure are being test at various temperatures. Hydraulic lines enter and exit the chamber through an access port. Rarely, if ever, a fluid leak occurs in the chamber. This does not concern the operator since the warmest temperature achieved in the chamber is well below the auto-ignition point of the fluid. However, if a leak occurs the chamber will be at risk for an explosion. This is due to the fact that the standard nichrome wire heater used in most chambers can exceed 1000˚F surface temperature.  4.For this type of application temperature limited sheath heaters must be used at a minimum. Depending on the application, a classified explosion proof chamber may be required. There are many scenarios which could be used for examples, but the bottom line is to make sure you have given your chamber manufacturer all the details of your tests.  

How to Prevent Condensation in Test Chamber

How to Prevent Condensation in Test ChamberAir contracts as it cools. When a chamber is pulling down, it actually causes outside room air to be “sucked” into the chamber workspace. The moisture in the air will be drawn to and freeze on the cooling coil. The moisture will then vaporize into the air when the chamber is heated up and that moisture can end up as condensation on the test product. Dry Air Purge or Gaseous Nitrogen (GN2) may be used to minimize condensation. Purging the chamber with either of the two maintaining a slight positive pressure on the chamber and minimizes the moisture infiltration into the chamber. The dry air or GN2 contains very little moisture so the chamber air can stay “dry”. To help avoid condensation on the walls and product with humidity chambers, bring up the air temperature. first, let the walls and product stabilize, then raise humidity. If the chamber air temperature and humidity levels are raised faster than the wall and product temperature, moisture will condense on the cooler surfaces. By maintaining the dew point of the air below the surface temperature of the walls and product, moisture will not condense on the surfaces. In most cases you can run a characterization test or two first, to determine how long it takes the largest mass (be it product or wall) to stabilize. 

Troubleshooting for Some Problems during Application

Troubleshooting for Some Problems during ApplicationClimate explains some frequent questions of temperature and humidity chamber during application:. First, the constant temperature and humidity test chamber in the course of a sudden test failure, the control instrument appears on the corresponding fault display prompts and voice alarm tips. The operator can quickly check out which type of failure is in the chapter on the troubleshooting of the operation of the device. The operator can quickly troubleshoot to ensure that the test is performed normally. Other environmental testing equipment in use there will be other phenomena, it is necessary to specific phenomena, specific analysis and exclusion. Second, in the high temperature test, such as temperature changes can not reach the test temperature value, you can check the electrical system, one by one troubleshooting. Such as constant temperature and humidity chamber temperature is very slow, it is necessary to view the wind circulation system, look at the wind circulation adjustment baffle is open normally, on the contrary, check the wind cycle motor running is normal. Such as the temperature overshoot so you need to set the PID set parameters. If the temperature rises directly, then the controller fails to replace the control instrument. Third, the constant temperature and humidity test chamber in the hot and humid test, the actual humidity will reach 100% or the actual humidity and the target humidity difference is very large, the value is much lower, the former phenomenon: the wet bulb sensor may be caused by drying, It is necessary to check the wet bulb sensor water tank is water, the water level in the tank is controlled by a water level controller, check the water level controller water supply system is normal water supply, water level controller is working properly. Another may be the wet ball gauze due to the use of a long time, or water quality purity of the reasons, will make the gauze hard, so that gauze can not absorb moisture and dry, as long as the replacement or cleaning gauze can rule out the above phenomenon. The latter phenomenon is mainly the constant temperature and humidity chamber humidification system does not work, check the humidification system of water supply system, water supply system, whether there is a certain amount of water to control the humidifier boiler water level control is normal, humidification boiler water level is normal The If everything is normal, it is necessary to check the electrical control system, which requires professional maintenance personnel to repair. Fourth, constant temperature and humidity test chamber low temperature can not reach the test indicators, then you have to observe the temperature changes, it is clear that the temperature drop is very slow, or the temperature to a certain value after the temperature has rebounded. The former will check whether to do before the low temperature test studio drying, so that the studio to keep dry after the test sample into the studio to do the test, the studio test sample is placed too much, so that the studio The wind can not be fully circulated, in the exclusion of the above reasons, we must consider whether the refrigeration system failure, and this will ask the manufacturers of professionals to repair. The latter phenomenon is the use of constant temperature and humidity chamber equipment, such as the environment is not good, the device placed in the ambient temperature, place (the distance between the box and the wall) to meet the requirements (in the equipment operating instructions are provided ).

How to add Water to Saturated Tank

How to add Water to Saturated Tank A) Open the power control cabinet door, you can see the transparent water level indicator on the saturated tank, observe the actual position of the saturated barrel and the position of the highest water level (top of the water level indicator).  B) Open the water adding valve of the saturated barrel (the water adding valve is open when it is perpendicular to the water pipe and is close when it is in parallel with the water pipe).  C) Add purified water to the water adding inlet as shown in the figure (do not add the brine into it by mistake), and make sure to observe the water level sign. When the water level meets the requirement, stop adding water and close the water adding a hand-control valve.  Attention: if there is not sufficient water in the saturator, please add proper amount of Purified water or distilled water into it. If in the fog spray state, please stop fog spray. When adding water, firstly open the charging valve of the saturated barrel, and add into it from the water supply inlet of the saturated barrel and close the charging valve after adding the water. The Water Checking of Saturated Barrel Check the water level of the saturated barrel. Open the chamber door of the power distribution cabinet on the right side of the equipment, the saturated barrel is located at the right lower corner of the equipment, and the transparent water pipe on the saturated barrel is the water level indicator. The water level reaching 80% of the full chamber of the saturated barrel is appropriate. When the water level falls to 40% of the full, it is necessary to replenish water in time to avoid causing the test to stop in the middle due to water shortage.  When adding water to the saturated barrel, the water level should not be too high. When water level is too high, air may enter the saturated barrel to bring out a lot of water to the sprinkler head, causing the spray volume to increase, and the actual salt fog settlement is not accurate.  When adding water, make sure to pay attention to the water supply inlet position to avoid adding water into the brine chamber and influencing the concentration of the test solution, thereby influencing the final test, or adding brine into the saturator by mistake. 

Difference between Air-cooled and Water-cooled Methods of Thermal Shock Chambers

Difference between Air-cooled and Water-cooled Methods of Thermal Shock ChambersClimate Thermal shock test chamber is mainly used for electrical and electronic components, automation components, communications components, auto parts, metal, chemical materials, plastics and other industries, defense industry, aerospace, military industry, BGA, Semi- conductor ceramic and polymer materials of physical change sacrificial, test the material of high and low temperature of the repeated resistance and the product of thermal expansion and contraction of the chemical changes or physical damage, you can confirm the quality of the product, from precision IC to heavy Mechanical components, will be used, is an essential test box in all areas of product testing.Thermal Shock Chambers include two boxes and three boxes types, and cold shock chamber cooling method includes two types: air-cooled, water-cooled, these two cooling methods have different differences:Water-cooled: the use of water mobility test chamber cooling work, which also is installed in the test chamber on the water tower, and the water tower can only be placed on the roof outside, cannot be placed indoor, to protect the water tower, make water pipe wrapped, cannot let it exposure or crack, so you can extend the life of the water tower.Air-cooled: The use of wind for natural cooling, this is more suitable for small power thermal shock chambers, if the test chamber ambient temperature is often kept at room temperature and equipped with ventilation device, the use of air cooling can be effectively extended Thermal shock chamber utilization and service life.The main purpose of these two cooling methods is for thermal shock test chamber cooling, by different ways, but the result is the same, mainly it depends on the test conditions how to choose and operate.

Technical methods for effectively extending the service life of ozone

Technical methods for effectively extending the service life of ozone aging test chamberOzone aging test chamber is applied tothe aging cracking test of nonmetallic materials and rubber products.It is effectively prolong the service life of ozone aging test box and reduce the amount of maintenance will play an important role in improving the economic benefits of the test. Technical methods for effectively extending the service life of ozone aging test chamber as follows:1. Keep the ground around and around the chamber clean at all times.2. It shall remove the internal impurities before operation, and clean the lab room at least once a year . 3. It not be allow the test specimen come into contact with the door seal strip when opening the door or taking the test specimen from the chamber4.  When the end of the test, do not take out the sample at once.It must be taken out of the shutdown state 5. The refrigeration system is the core of aging test chamber,check all the brass half a year, such as leakage of the situation, the functional joints, welding mouth, if the Leakage of grease, it must be dealt with immediately6. The condenser should be regularly maintained and kept clean.Dust sticky will make the compressor high-voltage switch trip and generate false alarm,So the condenser should be a monthly maintenance, you can use the vacuum cleaner, hard brush or high pressure air blowing dust to clean it,what attached to the condenser.7. At the end of each test,It is recommended to clean the test chamber with clean water to keep the equipment clean;After cleaning the box, the box should be dried to keep the box dry;8. Circuit breakers, over-temperature protection, and the operator's safety protection, please check regularly;

Four reasons resulting in the test result error of salt spray chamber

Four reasons resulting in the test result error of salt spray chamberSalt spray test chamber main for test the property of corrosion resistance of products’ surface, including electroplating, inorganic film, anti-rust oil and paint materials and other products. However, the device has the existence of test error. So many users also expressed doubts about the need for more accurate test data. Equipment in the course of the trial cannot ensure that 100% of the correct, in any case a little bit of data error. So what is the reason for it? According to the user feedback, have following reasons: First, the salt spray test chamber with their own errorOn account the design, manufacture and verification imperfection and the use of the test chamber in the process of its components aging, mechanical parts wear, fatigue and other phenomena formed by the error. Not only these parts will cause errors, but also various auxiliary equipment or accessories are likely to cause errors. Second, the error caused by the test methodThe method of operation should be carried out in accordance with the correct and standardized steps, and the test method should be reasonably improved. When the equipment test is based on the theory is not preciseness, unreasonable operation and the approximate formula or approximation of the calculation results and other factors will lead to test error. Third,the environment and the operator cause the errorDue to the actual environmental conditions differ from rated conditions caused error, the main factors are temperature, power supply voltage and electromagnetic interference. In addition, the operator's incorrect operation is one of the factors , the main reason is because the staff of the poor ability to distinguish, visual fatigue, detector speed is slow, bad habits and lack of responsibility and so on. Fourth, the error caused by the instability of the test sampleSalt spray test need a long time, if the test time to test the instability of the sample changes occur, that even if the performance of salt spray test chamber is no way to get the correct test data. 

What’s Adsorption Drier Is Used for in Temperature Humidity Chamber

What’s Adsorption Drier Is Used for in Temperature Humidity ChamberAdsorption drier applied very widely in temperature humidity test chamber. Today I will make a brief introduction for this device.The function of adsorption drier is to make the compressed air filter and try to make the water inside the compressed air being adsorbed. Then the air comes out will have very less water (like nitrogen).When the chamber from low temperature to high temperature. Because the test specimen is a little cold. If the air inside the chamber is wet, the surface of the test specimen will have dew formation.If at this time, we input the dry air from the Adsorption drier, then it will dilute the water in the air, to make the air become dry, then at the surface of the test specimen, it will not produce condensation

What does the performance characteristics of the walk-in test chamber

What does the performance characteristics of the walk-in test chamberThe field of walk-in constant temperature and humidity test is becoming more and more stringent with the requirement of quality control, that makes the demand for environmental testing equipment more and more, and its application field is more and more extensive. In order to make everyone understand this chamber well. Let me introduce exactly.Walk-in constant temperature and humidity chamber using advanced LCD touch screen, you can set a variety of complex procedures, set the program using dialogue, easy to operate, quickly. With a wide range of temperature and humidity control, to meet the various needs of customers. Using a unique balance of temperature control wet way to obtain a safe, accurate temperature and humidity environment. With a stable, balanced heating, humidification performance, can be high precision, high stability of the temperature and humidity control. Walk-in constant temperature and humidity test room equipped with high-precision intelligent temperature regulator, and temperature and humidity using LED digital display, can be selected temperature and humidity recorder. Its refrigeration circuit can be automatically selection, automatic control device can be set with the temperature automatically select the performance of the cooling circuit performance, in order to achieve high temperature direct start the refrigerator to cool. In addition to the installation of advanced protection devices such as: leakage circuit breakers, over-temperature protection, and water-break protection.

Why is airflow important for environmental test chambers?

Why is airflow important for environmental test chambers?When considering a new test chamber, you may be concerned about airflow speed? How fast should it be? Most test specifications don't say much on this subject, which makes it even harder to decide. In some cases low speed is acceptable and/or desirable, and others high speed is better.Test chambers need to circulate the air so that it can pass over heaters and coolers, ensuring a uniform air temperature. This is called "forced convection". You may think that "natural convection" is better to simulate real-world conditions, but it doesn't make a difference in most cases.Low speed: If your test application doesn't specify temperature change rate, or if it is relatively slow (less than 5 degrees per minute), then lower air speed is okay. Instead, concentrate on how the air is distributed to ensure it uniform.High speed: If your primary concern is changing the temperature of your test samples quickly, then you should be more interested in airflow. The faster the airflow, the quicker heat can be transferred from the air to your samples. There are diminishing returns from faster flow rates. Generally, it is accepted that 1,000 feet per minute (FPM) is the highest reasonable rate for test chamber applications. But in high performance applications, even 500 FPM is very effective.What is the cost of high airflow? Temperature change rate is reduced due to increased heat transfer. In addition, as it moves the air, it puts extra energy (i.e. heat) into the air, making cooling more difficult. ESPEC's line of Environmental Stress Screening chambers have high airflow and reasonable change rates. But with a 10°C/min. air change, your sample change rate will be about 8°C/min. A standard chamber with the same air change rate, but lower airflow, may only get a sample change rate of 3-5°C/min. Of course, the smaller your sample is, the faster it will change temperature.We sometimes run into confusion between the terms FPM (linear feet per minute) and CFM (cubic feet per minute). FPM is calculated by taking the CFM and dividing it by the cross-sectional area that it will be blowing through. CFM numbers can run very high, but when reduced to FPM, the actual air flowing past your product may not be as extreme as you thought it might be. For this reason, limiting the chamber size and cross-sectional area are important criteria for true ESS applications. 

Chamber preventative maintenance overview

Chamber preventative maintenance overviewLike the lifetime of your car, the lifetime of your test chamber depends on how well you take care of it. And the more severe the use, the more seriously care should be taken. Thus, humidity and high performance test chambers require more dedication to care than a benchtop temperature-only chamber.Like your car, cleanliness is the first thing you should take care of. It is smart to wipe the system down the inside of the chamber after every humidity test. Pulling the false-wall off and checking/cleaning the actual cooling coils and heaters should be done occasionally, too. Humidity systems should have their “steam generator” cleaned frequently to avoid a build-up of minerals. With many steam generators hidden out of site, this becomes particularly important to be aware of.The humidity detection system also needs to be checked. If yours is a “wick” based system (which standard LENPURE units use), the wick should be changed after every test to ensure reliable operation. Electronic, or solid-state, humidity sensors need to be calibrated a minimum of every six months.Speaking of calibration, the chamber controller typically should be calibrated once a year. These days this is hard to forget because many companies have quality systems like ISO keeping track of calibrations.If you have a smaller chamber, it probably is “air cooled”. You need to clean the condenser coil regularly to ensure it doesn't clog and impede cooling, much like you should on your home's refrigerator.Safety systems need to be tested regularly for proper operation, as well. At the very least, run a test to make sure the over-heat protection system(s) respond. An easy way to do this is to change the setting on these overheat system to below what the chamber is currently running to get a quick check on their operation.Pay attention to other sub-systems. If your humidity chamber has a water filter, see if it is time to replace. If you have a dry-air purge system, make sure it is actually running dry by checking it's visual indicator.Refrigeration systems should have their gauge pressures checked and compared with their previous readings. There isn't much else you can do with a refrigeration system without calling in an expert.

Specification for maintenance of rain test chamber

Specification for maintenance of rain test chamberWe would like to introduce some Maintenances of Rain Test Box as follows:1. Please check the water tank has enough water before operation, If not, please fill it avoid damaging the dump.2. Please stopped it once you heard some noisy, and rebooted after the trouble is solved, in order to avoid influence the service life of the equipments.3. It should be kept dry when the equipment is in nonworking condition. Please drain away water of the chamber and drying the chamber.4. After the equipment runs for a long time, if the nozzle is blocked, the pipe must be removed, washed with tap water, and then assembled;5. Avoid external force impact equipment;6. Chemical exposure to this equipment shall be prohibited;7. Check the circuit control system before each start.8. Ventilation fans should be installed in the laboratory to maintain ventilation;9. Check the Power supply and ground Wire10.Whether the power wire is properly connected to the specification and is truly grounded11. The waste water discharge system of the equipment must be installed in place12.After the test, the power supply of the whole machine will be cut off;13.After test, the sample should be removed and the equipment should be cleaned.If you want to know more information (some guidance or user-manual), please feel free to contact with manager@climatetester.com

What is the Salt Spray Test?

What is the Salt Spray Test?The salt spray test is an accelerated corrosion test conducted on materials and products to see how well they handle damage inflicted by salt. The material to be tested is usually placed into a chamber and a solution of sodium chloride is sprayed onto its surface. The test can help researchers and product designers develop paints, coatings, or film that is more resistant to salt damage. Salt damage is very rare for most types of products, however; the salt spray test is generally unreliable since it may not take into consideration many of the natural variables that cause corrosion.A salt spray test is also known as the salt fog test. A sample is usually placed in a temperature controlled container and a 5% sodium chloride solution is dispersed onto it. The sample is wet throughout the test and the temperature is kept constant. The test duration can be anywhere between 24 hours and 1,000 hours. At regular intervals, the samples are rotated to allow even coating of the salt solution.The result of the test is rusting of a surface. The number of hours until the first sign of rust is noticed is recorded. Other methods include recording the number of hours until 5% of the surface is rusted. The criteria differs among laboratories.One of the best way to prevent rusting on steel is to coat the steel with zinc or aluminum. Galvanized steel is coated with zinc and generally lasts about 10 hours in the salt spray test. The best performing steel is typically coated with aluminum and zinc. It lasts about 50 hours before 5% of the surface is covered with rust.This coating is important for applications that are exposed to the weather, such as roofing material. It is recommended that roofing material be coated with zinc before the paint layer is applied. This will reduce corrosion associated with rain or surf splash.The salt spray test doesn't take into account the exposure to ultraviolet rays, which are primarily responsible for degrading painted materials. Another questionable aspect of the test is the fact that the sample is exposed to wet conditions continuously. This may not be the case for most products when they are actually used. The test also produces discrepancies between identical samples during testing. For example, one sample may take 5 hours for rust to form, while an identical sample may take 10 hours.