Litʹë i Metallurgiâ (Apr 2020)
Checking the sensitivity and accuracy of humidity indicators
Abstract
Discusses the problems of protecting the goods during transport from exposure to high humidity and ways of its solutions; the presence of some consumers ‘ requirements for adherence to the maximum values of humidity and confirmation of its actual value in the packed products; the use of paper humidity indicators to control the environment during transit; the principle of operation of the indicator based on the change in color of cobalt salts depending on the composition of the crystalline.There is a lack of methodology for quality control of paper humidity indicators. The method developed by the laboratory of OJSC «BSW» – Management Company of the Holding «BMC», to determine their sensitivity and accuracy is given. The essence of the test is to assemble an installation that provides a certain value of air humidity. To do this, we use solutions of sulfuric acid of the appropriate concentrations. Air is passed first through water, then through solutions and fed into a flask with an indicator. Depending on the humidity of the supplied air, the corresponding indicator points change colour. Sensitivity and accuracy are evaluated on a colour scale.
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