April 27, 2022
1. Types of Tests Conducted Using a Temperature Chamber
A temperature chamber is a term used to describe a chamber that performs a variety of environmental tests. Excessive heat is one of the most common causes of product failure, which makes it necessary to test a new or existing product for those conditions.
The test types are completed by a temperature chamber that provides data regarding extreme temperature variations and the effects of high humidity. These tests establish limits for a product design and provide data regarding defects or premature failure of the product..
- Extremes of Temperature
- Thermal Shock
- Humidity
- Altitude
2. Types of Temperature Chambers
Temperature chambers come in a variety of sizes and types, from one that can be placed on a shelf to another the size of a building. The essential factors for choosing a temperature chamber are the amount of space available and the desired conditions to be created.
While a generic test chamber can be purchased, in most cases the customer works with the manufacturer to design a chamber that specifically meets the customer's requirements. There are different factors that each client wants to check and the chamber they choose must meet those criteria..
- Portable Temperature Chambers
- Benchtop Temperature Chambers
- Reach-In Temperature Chambers
- Drive-In Temperature Chambers
3. Temperature Chamber Construction
In the majority of cases, environmental testing laboratories are designed according to the specifications and requirements of the customer as each industry has different testing needs and requirements. Regardless of specialization and variants, aspects of all test chambers are the same such as materials, doors, seals, air circulation devices and controls, although the controller varies depending on the condition being monitored. The components of the temperature chamber include:
3.1 Walls: The walls of temperature chambers have an exterior of steel with a stainless steel inner lining. The stainless steel interior has 304 or 306 grade steel. The materials chosen for chamber construction are used for their resistance to corrosion and sturdiness. Test chambers are built, produced, and designed to last as well as be able to endure the stress put on them by the various tests.
3.2 Insulation: Between the steel exterior panels and stainless steel interior panels is insulation. There are several forms of insulation used in test chambers, which can be certain forms of silicone, fiberglass, and polyurethane. In most cases, polyurethane is used for its low thermal conductivity and high performance as a thermal insulation.
3.3 Doors: A critical factor in door construction is the ability to form a tight seal as well as being very sturdy and rugged enough to withstand constant and continuous use. They have full action clamps that hold them in place. As with the walls, they have a sealing material that prevents contamination of the chamber by ambient materials. In many cases, they have a double paned window made of glass or a clear polymer, which is also tightly sealed. The larger the size of the chamber the more doors it may have, which are double sealed.
Larger chambers also have a defogger or heating cord to prevent condensation on the windows.
3.4 Controller
i) + One of the most important components of a temperature chamber is the controller, which comes in a variety of types, programs and components. The key factor for the controller is its ability to maintain the programmed conditions with very small changes.
ii) + The most important part of the controller is data accuracy and reliability. They need to be easily configured and adapted to a wide variety of products and conditions. The program must strike a balance between accurate data and ease of programming. Each controller has several features. Most have color LCD displays and a wide range of application features. They are compatible with computers with USB ports for easy data transfer.
3.5 Air Flow: Free airflow is key to an efficient temperature chamber. It is one of the factors that ensures that the temperature is distributed to all spaces in the chamber. Temperature chambers require either a motor-driven blower or an axial fan to distribute the air evenly throughout the chamber.
3.6 Cooling: There are several methods used to cool the temperature chamber. For smaller chambers, heat is vented out through an air-cooled condenser. Larger chambers require a more complex cooling system, which can be in the form of water-cooled or nitrogen-cooled.
3.7 Heating: The temperature chambers are heated using wire heaters made of Nichrome. The heater conductors are wound into a ring to generate the greatest amount of heat. Airflow circulates heat in the chamber for even heat distribution. This prevents the sample from being exposed to radiant heat. The amount of heat a chamber can generate is limited by the material it's made of because certain insulation materials cannot withstand extreme temperature ranges.
4. Weaknesses Temperature Testing Identifies
Temperature creates stress in a product and is something every product experiences during its usefulness. How important temperature is for a product varies from product to product. Most typically, electronics experience more temperature stress due to the nature of how they operate.
There are certain temperature tests that can be performed to determine the viability of a product. The basic forms of tests are high and low temperature, thermal cycling, thermal shock, and temperature with humidity.
High Temperature Testing
There are various factors that can be identified by high temperature testing.
+ Parts and insulation melting
+ Shortened life span of parts
+ Increased heat causes a chemical reaction or oxidation
+ Various electrical components overheat and fail
+ For large equipment and machines, lubricants can have altered viscosity
+ Structural and mechanical changes
Low Temperature Testing
+ Loss of flexibility and brittleness
+ Shift in electrical constants
+ Components freezing upác thành phần bị đóng băng
+ In large equipment, lubricants turn to gel or become more viscous
+ Rapid heat loss
+ Cracking, peeling, or flaking of surfaces
Rapid Cycling of Temperatures
+ Alter reactions of parts at different temperatures
+ The size and shape of the material changes
+ Insulation, seals, gaskets, and shafts or bearings are reshaped and disfigured
+ The performance of circuits fluctuates at varying temperatures
+ Joints and connectors crack or disengage
+ Circuit boards fail
5. Rapid heat loss
Food and Drug Administration (FDA)
Các The requirements for the FDA are not specific to temperature chambers. They are more in regard to the food equipment that is tested in the chambers and specify the types of acceptable tests that qualify food production equipment for sale.
International Organization for Standardization (ISO)
ISO has established standards for accepted test methods for a wide range of products. It is an international organization that has been recognized by the majority of countries. They have a specific list of requirements related to testing practices and how to implement them.
Some ISO standards:+ ISO 11507 - Thử nghiệm sơn và vecni
+ ISO 29664 - Testing of paints and varnishes
+ ISO 4892-1 và 3 (EN) (DIN) - Testing of plastics
Conclusion
1) A temperature chamber is a controlled environment capable of producing conditions that a product will encounter during its use.
2) Temperature chambers test the prolonged effects of a varied range of temperatures to examine the quality parameters of a product or part.
3) Temperature chambers provide the opportunity to create manufactured environments and conditions that can simulate the types of conditions that a customer may face with a product.
4) Temperature chamber is an umbrella term used to describe a chamber that conducts a variety of environmental tests.
5) Temperature creates stress in a product and is something every product experiences during its usefulness.