About Constant Temperature Humidity Test Chamber

The constant temperature and humidity test chamber is a highly precise testing equipment that can perform constant humidity and temperature performance testing on products under simulated natural environmental conditions to evaluate their performance, stability, and durability.


1 Composition of the system

The equipment consists of five major systems, including control system, refrigeration system, heating system, humidity system, and air circulation system. The control system is the core of the test chamber, which determines important indicators such as the temperature rise and fall rate and accuracy of the test chamber.


At present, most controllers for constant temperature and humidity test chambers use PID control, with a few using a combination of PID and fuzzy control as control methods. The DGBELL constant temperature and humidity test chamber adopts logic control and dual PID control methods: achieving faster response, faster stability, and more energy saving; The temperature fluctuation, temperature deviation, and temperature uniformity have reached a higher level.


The refrigeration system is an important component of the test chamber, usually using mechanical refrigeration, namely steam compression refrigeration, mainly composed of a compressor, condenser, throttling mechanism, and evaporator. According to testing requirements, refrigeration methods can be divided into single-stage refrigeration and cascade refrigeration. For temperature tests below -40 ℃, cascade refrigeration is generally recommended.


The heating system is relatively simple and mainly composed of high-power resistance wires. Due to the high heating rate required by the test chamber, the power of the heating system needs to be matched according to the temperature rise and fall requirements and system configuration.


The humidification and dehumidification subsystems of the humidity system are crucial for simulating humid climates. The humidification method generally adopts steam humidification, which means that low-pressure steam is directly injected into the test space for humidification or shallow water plate humidification is used. This method has a fast speed, sensitive humidification control, and is especially easy to achieve forced humidification during cooling.


The air circulation system consists of a centrifugal fan and a motor that drives its operation, ensuring the circulation of air inside the test chamber to balance the temperature and humidity inside the chamber.


The working principle of the constant temperature and humidity test chamber is to achieve gas circulation through the rotating fan at the top of the chamber, promoting the temperature and humidity inside the chamber to reach an equilibrium state. And collect data through the built-in temperature and humidity sensor, transmit it to the temperature and humidity controller for processing, and issue temperature and humidity adjustment instructions.


This device has multiple protective measures, such as the temperature system being equipped with an over temperature protector, and the air heating element automatically powering off when the rotating fan stops; The humidification system can stop supplying power as the water level in the humidification tank decreases; The refrigeration system also operates according to the set logic as the temperature or humidity of the chamber increases.


2 Function

The main functions of the constant temperature and humidity test chamber include high temperature testing, low temperature testing, humidity testing, constant temperature and humidity testing, and humidity and heat testing. For example, high temperature testing can reach 150 degrees Celsius, while low temperature testing can reach minus 70 degrees Celsius.


Damp heat testing simulates complex and abnormal climate changes to evaluate whether the product has sufficient resistance to alternating humidity and heat. (Special scope requires customization)


The parameters of the constant temperature and humidity test chamber are key indicators for measuring its performance and function, and are crucial for ensuring the accuracy and reliability of the test. Here are some common parameters:


Temperature range: Describe the minimum and maximum temperatures that the test chamber can simulate, such as from -70 ℃ to +150 ℃. This determines the testing temperature range that the test chamber can adapt to.


Humidity range: The relative humidity range that the test chamber can simulate, commonly ranging from 20% to 98% RH, but can also be customized according to different needs.


Temperature and humidity fluctuation: The degree of temperature and humidity fluctuation inside the chamber in a stable state. This is usually represented by ± X ℃ and ± X% RH, with smaller values indicating higher control accuracy.


Temperature and humidity uniformity: Ensure that the temperature and humidity distribution in different positions inside the chamber is uniform, which is crucial for the consistency of the test samples.


Temperature and humidity deviation: mainly reflected in the difference between the set value and the actual value, reflecting the accuracy of the experimental objectives.


The constant temperature and humidity test chamber is a multifunctional and high-precision testing equipment widely used in multiple industries, which is of great significance for product research and development, production, and quality control.


3 Application area

Electronic products: Conduct environmental adaptability testing on electronic components, communication equipment, etc.


Automotive industry: testing the weather resistance and reliability of automotive components.


Food and Drugs: Evaluate the stability and shelf life of food and drugs under different temperature and humidity conditions.


Materials Science: Studying the performance changes and aging processes of materials in different environments.


Aerospace: Ensuring the performance of aviation equipment under extreme weather conditions.


In addition, constant temperature and humidity test chambers are essential testing equipment in aviation, automotive, household appliances, scientific research, and other fields, used to test the parameters and performance of electrical, electronic, and other products and materials after temperature environmental changes.


In practical applications, the constant temperature and humidity test chamber can provide a standardized testing environment, ensuring the accuracy and reliability of test results. Enterprises can improve the environmental adaptability of their products through experimental data.

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