May 6, 2022
Introduction
This article contains everything you need to know about humidity chambers.
- What is a humidity chamber?
- How a humidity chamber works
- The types of humidity chambers
- The industries that use humidity chambers
1. What is a Humidity Chamber?
The humidity chamber is a mechanism that tests how a product reacts when exposed to changes in humidity. This type of environmental test is used by manufacturers to test various parameters of their products under the most extreme conditions.
The purpose of the humidity chamber is to test the effects of different environments on products to determine their usefulness and when they will fail. The data collected helps engineers refine their designs and select more resilient materials.
Different types of humidity chambers allow the test to be completed either statically or dynamically depending on the required data and product type. Humidity chambers are used as extended test chambers to determine the response of specimens to high humidity conditions when exposed for weeks or months.
2. How a Humidity Chamber Works
Two factors affecting product stability are temperature and humidity, of which humidity is the second most damaging factor. It is for this reason that manufacturers test the effects of moisture on their products because fluctuations in humidity cause expansion and contraction. The three basic methods of creating artificial humidity are a steam generator, a nebulizer, and a water bath. The homogenized form of the test chamber is also used to test humidity as well as temperature changes and vibrations.
Steam Generators
The steam generator has an immersion heater that heats the water inside the chamber. When steam is generated it rises to the top of the chamber, where there is a heater to create humidity. The steam chamber is capable of generating heat from 300°C to 1300°C from the CNC programmed control panel. The main benefits of a steam generator's humidifier chamber are its ability to produce large amounts of moisture with consistent steam quality.
Nebulizer
The spray test chamber has a nozzle for spraying atomized water as a means of humidification and humidification. As the water passes through the chamber heater, it is heated to create humidity. The operation of the mist test chamber is simple and straightforward, and is capable of generating large amounts of moisture.
Water bath
Water bath test chambers work on the same concept as a steam generator without an enclosed box. A small water bath is fitted in the mixing plenum with the heater. As air enters the assembly, it passes through the bath where it picks up the water vapors. This form of chamber provides a quick response since it uses a small amount of water and does not require the temperature of the water to be at the boiling point.
3. Industrial Use of Humidity Chambers
Automotive
The primary function of a humidifier chamber for the automotive industry is to simulate weather conditions by injecting hot air filled with moisture into the chamber. The ability of cars to withstand the conditions they endure is an important issue for manufacturers. By ensuring a vehicle can withstand all types of weather it will encounter is important for the longevity of the vehicle and the safety of its passengers.
Humidity chambers for the automotive industry come in many varieties with those designed to test individual components and assemblies with others large enough for cars to drive in.
Rubber
Rubber is greatly affected by climatic conditions. It is highly tolerant but susceptible to changes due to temperature and humidity. The purpose of the humidity chamber is to test the performance of the rubber when subjected to 95% humidity. By using a humidity chamber, it is possible to determine the cracking and melting characteristics of rubber.
Pharmaceutical
Humidity is an important factor in the pharmaceutical industry because moisture can cause drugs to degrade rapidly, which makes moisture test data important for determining drug stability. . The parameters for humidity testing vary but are measured in accordance with the amount of steam introduced into the chamber.
Air is composed of nitrogen, oxygen and other elements. Between the molecules of these elements is water. The ratio of molecules to the amount of water that the molecules hold is moisture. When the air is heated, the molecules move away from each other, leaving more room for water. This is the element that is tested in the humidity chamber as the temperature rises. The data provided let the researchers know at what temperature humidity would damage or degrade the drug.
Plastic
Exposure to moisture can cause the resin to discolor, crack, chalk, and become brittle. It is important that we check these factors as they can lead to damage to the plastic product. In most cases, plastics are put through heat-humidity cycles, determined by the product's durability requirements.
Auto manufacturers have a set of standards and requirements for their plastic parts. The humidity chambers are designed to reproduce conditions in order to test the operation of product components under extreme conditions. The location of the part in the vehicle determines the severity of the test.
Electronics
An important aspect of the production of electrical components and complete systems is to determine the humid conditions that result in the failure of components. The conditions that are tested vary between 60% to 85% humidity. The purpose of the testing is multidirectional and is used to determine how products will perform in storage, shipping, and in harsh operational conditions.
When testing electronics, it is not necessary to examine humidity at low temperatures. As the temperature rises above 50° C, humidity becomes an important factor in how a product will perform. In those conditions, humidity has to be measured for condensation on electronic devices.
Aerospace
Much of the testing for aerospace products is similar to that for electronic components since aerospace instruments are subjected to harsh conditions. One of the tests used on aerospace products, due to the exposure to varying climatic conditions, is thermal cycling where a component is put through wet and dry atmospheres in rapid succession.
The time between exposure depends on how the part will be used and its type. For aerospace products, there are a strict set of standards that manufacturers are required to follow. Many of them correspond with those established for the military.
Military
The conditions that products for the military have to be tested against are wind, rain, dust, and extreme heat. Humidity chambers are able to replicate high moisture atmospheres in a controlled environment to provide substantial data regarding the ability of a weapon or component to survive harsh conditions.
The United States defense standards or military standards are identified by codes, which are represented by MIL-STD, MIL-SPEC, or MilSpecs. Adherence to these codes ensures that products for the military meet the required specifications for reliability, compatibility, and interoperability. In the case of humidity, the standards define the correct heat to moisture ratio for how a part, mechanism, or assembly will be used. The conditions of the testing vary depending on the specified environment. The specific regulation regarding humidity is MIL-STD 810 G, which applies to materials that will be deployed in warm or humid environments.
Medical
All instruments and equipment that are used for medical purposes have to be thoroughly tested prior to being sold or marketed. Much like the pharmaceutical industry, the medical industry has to adhere to stringent governmental guidelines, standards, and regulations. These restrictions apply to equipment used to test medical devices that will be used for patient care.
Humidity chambers serve several purposes regarding the performance and capabilities of medical instruments. The initial purpose is to ensure that the instruments will not become contaminated or are not contaminated. A second purpose is to determine the shelf life of the instruments and at what point they will need to be disposed of or replaced.
Battery
Testing the weathering capabilities of batteries is an essential part of ensuring their high quality performance. The critical factors that need to be determined regarding batteries is their durability, susceptibility to corrosion, and over all performance. Humidity chambers are used to do rapid cycling of batteries through a variety of environmental conditions.
Humidity chambers for batteries have special fixtures that allow the testing of over 50 batteries during one testing cycle. By being able to test multiple configurations of batteries in a single test cycle, researchers can gather a wide range of data regarding each of the different design.
Unlike other forms of humidity chambers, battery testing chambers have to have additional electrical cables to be attached to the batteries during testing. To allow for the testing of multiple batteries, shelves or special fixtures are added as well. To ensure that a humidity chamber is capable of testing batteries, it has to be examined for the special battery fixtures and cables
