Learn Something About Environmental Test Chambers

All industry products for everyday life are affected by the natural environment and, over time, directly to the point of being unusable. To check the reliability of the product, the environmental test chamber simulates and accelerates environmental changes or simulates situations that the natural environment cannot reach. Therefore, with the help of environmental test chambers, we can obtain information on how long the product can be used in the natural environment and understand how well the product survives in extreme environments. In this way, the purpose of controlling product quality is achieved.

General Introduction of Environmental Test Chambers

The environmental test chamber is used to test whether the specimen is intact and functional under specific conditions. The environmental test chamber is composed of two parts: environment and test chamber. Environment refers to various environmental conditions, which are the sum of the external conditions that the specimen to be tested is subjected to in a given time, which can be mechanical, climatic, biological, and other environments. Test chambers are enclosed spaces that can meet the specified test conditions and are used to simulate different test environments. One of the most important test items is the climatic chamber test, such as high temperature, low temperature, high humidity, low humidity, light, and even alternating humid heat cycle test. Environmental test chambers mainly involve the reliability test of electronic components, chemical and new energy material stability investigation, automobile and parts design and manufacturing, semiconductor wafer production and packaging, drug (chemical, traditional Chinese medicine and biopharmaceutical) related stability research, cosmetics and food microbiology testing, third-party testing.

If there is something wrong with the product, it is likely to be caused by external factors, such as temperature, humidity, vibration and other different use environments and scenarios, which were not expected or considered in the design. For example, from warm to cold climates, different corrosion effects, and many other factors. In addition to the conditions of use, consideration is given to the various stresses that the product may experience during packaging, transportation and storage operations that can cause damage to the product or shorten the service life of the product.

When items are placed outdoors, they are likely to be affected by the natural environment such as wind, sun, altitude, humidity, cold, shock, salt spray, sand and dust. For different natural environments, there are different testing standards and different types of environmental test chambers.

Common environmental test chambers mainly include:

1.temperature and humidity test chamber,

2.thermal shock test chamber,

3.salt spray test chamber,

4.xenon accelerated weathering test chamber,

5.UV weathering test chamber,

6.sand and dust test chamber,

7.water spray test chamber,

8.ozone test chamber,

9.noxious gas test chamber

How Environmental Test Chambers Work?

The working principle of the environmental test chamber can be mainly explained by the two physical parameters of temperature and humidity.

The environmental test chamber consists of two parts: temperature regulation (heating and cooling) and humidification. Through a rotating fan installed on the top of the chamber, air is discharged into the chamber, which circulates the gas and balances the temperature and humidity in the working room. The data collected by the built-in temperature and humidity sensor of the chamber is transmitted to the controller for editing and processing to achieve the purpose of adjusting temperature and humidity.

1.Temperature control

To control the temperature, the test chamber must be able to perform two functions: heating and cooling. In addition, it must be possible to regulate the temperature inside the chamber evenly. Specific air distribution technology in the environmental test chamber guarantees a high temperature uniformity throughout the test chamber, ensuring that all components and surfaces are at the same temperature.

The mechanical cooling system of the environmental test chamber is composed of a closed circuit system, and the main components are: compressor, condenser, expansion valve, evaporator.

2.Humidity control

In order to control humidity, the test chamber must be able to perform both humidification and dehumidification tasks, and must also be able to achieve an even distribution of humidity in the chamber.

Direct humidification is achieved with an electric humidifier, which injects steam through the airflow holes behind the air recirculation fan. The humidifier is controlled by a dedicated algorithm for increased reliability.

The test chamber is dehumidified by a mechanical system based on the principle of condensation, using the same mechanical system as cooling. According to this principle, when a cooler object is exposed to a warmer environment, moisture in the air condenses on the surface of the cooler object. The evaporator is the coldest element in the test room, so it will be used with a dedicated section to reduce the humidity level in the test room.

What Tests Can be Performed by the Environmental Test Chamber?

We use different environmental test chambers for different purposes. For environmental testing, they are commonly used for four main types of testing.

1.Consistent temperature test

A test chamber that controls temperature, humidity or other factors within a certain range and maintains that temperature for a certain period of time. You can use this type of test to measure the useful life of a product or to test its stability in a specific environment over time. The results of this test will be more accurate.

It can simulate the adaptability of products under different environmental conditions such as high temperature and high humidity/high temperature and low humidity/high temperature/low temperature. Widely used in product testing in industries such as electronics, food, automobiles, rubber and plastics, metals, chemicals, and building materials.

2.Thermal cycle test

In this test, the test chamber presents your product with two extreme environments and switches between them for a period of time. It's a slow process. Product changes should be visible during testing.

3.Thermal Shock Test

The test is exactly what it sounds like - a test chamber that quickly provides your product with an extreme environment. Then, you'll learn the limits of their ability to handle extreme environments.

4.Salt spray test

Also known as salt spray corrosion test, it is a well-known corrosion test. By this test, you can discover the usability of your product in real environment.

Thermal cycle test and thermal shock test, while similar, are not the same. Thermal cycle test is a slower process than thermal shock test. While both provide two environments for a product, thermal cycle test is slower than thermal shock test. Thermal cycle test will provide manufacturers with accurate results when controlling specific temperature and humidity. Thermal shock test, on the other hand, will give you data on the durability of the product when it is switched between two extreme environments.

Temperature Deviation and Fluctuation

For high and low temperature test chambers, in addition to the temperature range mentioned at the beginning, we will also focus on the following key indicators.

Temperature change rate: The value of the temperature rise/fall inside the test chamber per minute.

Temperature deviation: After the device reaches the set value and stabilizes, record the temperature value of each measuring point and the temperature value indicated by the device, once per minute, a total of 30 times. The deviation of the maximum/minimum value from the set value in the process is the expected value.

Temperature fluctuation: Using the data collected during the above temperature deviation process again, the maximum temperature difference of each collection point in the working space within 30 minutes.

Temperature uniformity: The above data is also used, and the arithmetic mean value of the maximum space temperature difference between 30 test points per minute within 9 minutes is taken.

Although the temperature uniformity can indicate the quality of the temperature balance of the chamber, the factors of temperature fluctuation at each point are basically removed due to the multiple average method used in the calculation.

However, for the temperature performance index of the test chamber, it is not enough to only mark the temperature uniformity. There must also be a temperature fluctuation index, that is, the temperature change of each point with time, in order to fully describe the temperature change field in the test chamber, especially when the temperature fluctuation is larger.

How to Choose the Most Suitable Chamber?

1.Size

When putting the specimen into the environmental chamber for testing, in order to ensure that the conditions around the test product can meet the environmental test conditions specified in the test specification, the volume of the working chamber should be at least 3 to 5 times the product profile volume.

2.Temperature range

The higher the upper temperature limit, the greater the temperature difference between the inside and outside of the chamber, the more uneven the flow field inside the chamber, and the smaller the volume of the usable working chamber. On the other hand, the higher the upper limit temperature, the higher the heat resistance requirement for the insulation material in the inter layer of the chamber wall. The higher the requirement on the airtightness of the chamber, the higher the manufacturing cost of the chamber.

At present, the temperature test chamber generally ranges from -70°C to +180°C. These temperature ranges generally meet the temperature testing needs of most military and civilian products.

3.Humidity range

Most environmental chambers use the wet and dry bulb method when measuring humidity. Most of the humidity indicators given by the environmental test chamber are 20%~98%RH.

4.Cooling

If the test chamber has a refrigeration system, the refrigeration system needs to be cooled. There are two types of test chambers: air-cooled and water-cooled.

Which Industries are the Environmental Test Chambers Used for?

1.Aerospace

Environmental test chambers are used in the aerospace industry to simulate and reproduce typical environmental conditions during landing, take-off and flight phases to ensure qualified, reliable and high standards of product performance and quality.

2.Automobile

Regulations in the automotive industry are constantly being updated and safety requirements are constantly increasing. In addition to the fundamental issue of driver and passenger safety, there is also the issue of complying with emissions regulations to protect the environment.

3.Electronics

Environmental test for electronic equipment is to reduce the risk of product failure. Test is essential to ensure a long service life and maintains its original performance.

4.Batteries

The battery test environmental chamber is specially designed for lithium-ion battery testing. The purpose of the test is not only to check battery life, but also to check the level of safety under certain environmental conditions.

5.Other

In addition to all those mentioned above, environmental test chambers can also be used in the food industry, building industry, energy industry, pharmaceutical industry, etc.

How to Maintain the Environmental Test Chamber?

Usually, the working conditions of the environmental test chamber in hot summer can reach 50°C. In this environment, the use of the test chamber will be affected, such as: the cooling ability becomes weaker, the working condition becomes worse, and the alarm protection of overpressure and overcurrent increases, etc. . Therefore, in order to prolong the service life of the test chamber, ensure the accuracy and stability of the equipment during operation, and prevent the test chamber from malfunctioning, which will affect the normal test and test results, the maintenance of instruments and equipment at high temperature in summer is very important.

LIB INDUSTRYis a professional manufacturer and designer of Environmental Test Chambers in China. Since we have too much experience in dealing with environmental test chambers, we will summarized for you on how to maintain the machines：

1. Check the working environment temperature of the equipment

When the equipment is running in summer, the operator should always check the temperature around the equipment. The normal operating temperature range is +5°C~+30°C. It is recommended that the laboratory be equipped with air conditioning facilities.

2. Maintain a ventilated and safe environment

The working environment should be well ventilated. There should be no dust and debris around the environmental test chamber. It is forbidden to store flammable, explosive, strong radiation and strong corrosive items and materials. Beware of fire and ensure that the equipment is well grounded. The surroundings of the test chamber must not be subject to strong vibration and the influence of electromagnetic fields.

3. Regularly check the system settings

Equipment management personnel need to regularly check whether the environmental temperature control system (such as air conditioners, exhaust fans and other equipment) is normal to ensure that the performance meets the requirements of the summer test, regularly inspect the water circulation cooling equipment such as water towers and pumps, and shorten the maintenance cycle.

4. Regular cleaning and dust removal

Clean the inside and outside of the chamber at regular intervals to keep the inside and outside of the test chamber clean. The dust on the air-cooled condenser should be removed regularly, and the water-cooled water tower and filter should be cleaned regularly to ensure good heat exchange efficiency.

5. Ensure the stability of the power supply voltage

Power distribution personnel need to ensure that the power supply voltage is within the rated range, and beware of overload and short circuit; the screws of the circuit connection parts are regularly checked and tightened.

Summary

The high temperature in summer can easily affect the environmental test chamber, so the operator needs to carefully follow the operation process to carry out the test. If there is a problem with the test chamber, you should contact the after-sales service team of LIB INDUSTRY for inspection and maintenance in time, so as to ensure the normal test and prolong the life of the test equipment.