What Is the Basis For the Temperature Humidity Test Chamber?

The temperature humidity testing chamber is mainly used to test the constant temperature and humidity of products. It is often used in plastic rubber, electronic and electrical industries, automotive parts industry and so on. They need to test the products produced and studied under certain humidity and temperature conditions in order to test the stability of products under these conditions. Because the temperature humidity testing chamber has its technical characteristics and test complexity, it is time-consuming and laborious for buyers to choose a suitable temperature humidity testing chamber. So what principles should be followed in choosing the temperature humidity testing chamber?

1.Reproducibility

It is impossible to reproduce completely and accurately the environmental conditions existing in nature in the environmental chamber. However, within a certain tolerance range, people can accurately and approximately simulate the external environment conditions experienced by engineering products in the course of use, storage, transportation and so on. This paragraph is summarized in engineering language as "the environmental conditions (including the platform environment) created around the test equipment created by the test equipment should meet the environmental conditions and tolerances specified in the product test specifications". For example, the temperature box used in military product test should not only satisfy the test value and test time of high and low temperature according to different types of products stipulated in the national military standard GJB150.3-86 and GJB150.4-86, but also meet the requirements of uniformity of temperature field and precision of temperature control in test specifications. Only in this way can we ensure the reproducibility of environmental conditions in environmental testing.

2.Repeatability

An environmental test equipment may be used for multiple tests of the same type of product, and an engineering product may be tested in different environmental test equipment. In order to ensure the comparability of the test results of the same product under the environmental test conditions specified in the same test specification,  the environmental conditions provided by the environmental test equipment to be reproducible are required..That is to say, the stress level (such as thermal stress, vibration stress, electrical stress, etc.) applied to the tested products by environmental testing equipment is consistent with the requirements of the same test specification.

The repeatability of environmental conditions provided by environmental testing equipment is guaranteed by the National Metrology and verification department after the verification is qualified according to the verification rules formulated by the National Technical Supervision agency. Therefore, environmental testing equipment must be required to meet the requirements of various technical and accuracy indicators in the verification regulations, and the use time should not exceed the time limit stipulated by the verification cycle. For example, if the use of the very common electric vibration table meets the technical requirements such as excitation force, frequency range, load capacity, etc., it must also meet the requirements of the lateral vibration ratio, mesa acceleration uniformity, harmonic distortion degree, etc. specified in the verification regulations. And the use period after each verification is two years, more than two years must be re-qualified before they can be put into use.

3.Controllability

The environmental conditions provided by any environmental test equipment must be controllable, not only to limit environmental parameters to within certain tolerances, but also to ensure reproducibility and repeatability of test conditions. From the safety of product testing, the controllability of environmental testing is also very important, in order to prevent damage to the tested products due to out of control of environmental conditions, resulting in unnecessary losses. The accuracy of the parameter test generally required in various test specifications should not be less than one third of the allowable error of the test conditions.

4.Exclusiveness

Every environmental test has strict regulations on the category, magnitude and tolerance of environmental factors, and excludes the effect of non-experimental environmental factors, so as to provide a precise basis for judging and analyzing product failure degree during or after the test. Environmental testing equipment is not allowed to add other environmental stress disturbances to the tested products except providing the prescribed environmental conditions. For example, rharmonic distortion and other accuracy indicators are designed to ensure the uniqueness of environmental test conditions in the andom signal testing.

5.Safety and Reliability

The test period for environmental testing is long. The object of environmental testing may sometimes be a product of high value. During the test, the tester often has to operate or test in the temperature humidity testing chamber. Therefore, the environmental test equipment must be safe to operate, easy to operate, reliable to use, long working life, etc. Features to ensure the normal conduct of the test itself. When the temperature humidity testing chamber manufacturer produces the test equipment, the alarm device and the safety interlock device of the test equipment must be considered in order to ensure the safety of the test personnel, the test product and the test equipment itself.

When choosing the temperature humidity testing chamber, maybe everyone will be confused. But as an environmental chamber manufacturer, it is very clear to tell you that choosing constant temperature humidity testing chamber is not only based on reliability and cost performance, but also should be combined with the above five principles.