The selection of packaging container materials and the treatment process of the inner wall of packaging containers are very important in order to keep the composition content of standard gases and mixed gases in Hubei basically unchanged for a long time. High pressure steel cylinders are one of the most commonly used packaging containers for mixed gases and standard calibration gases.
Generally speaking, the main reasons for changes in gas composition inside a bottle are as follows:
Chemical reaction occurs between gas components and the inner wall material of the bottle; Gas components are adsorbed on the inner wall of the cylinder; Gas components react with residual water vapor in the bottle or are dissolved and absorbed by water; The inner wall of a steel cylinder adsorbs impurities, components, gas desorption, etc. Due to the above reasons, strict treatment of the inner wall of the gas cylinder must be carried out before filling it with a standard mixture.
The commonly used processing methods include: polishing the inner wall of the cylinder; Galvanizing treatment for the inner wall of steel cylinders (such as galvanizing, nickel, chromium, copper, gold, etc.); Phosphating treatment on the inner wall of steel cylinders; Chemical coating treatment on the inner wall of steel cylinders, etc. New methods for handling the inner walls of cylinders are constantly emerging. For example, according to a Japanese patent report, after acid washing and vacuuming, the inner wall of the cylinder is filled with oxygen or oxygen-containing gas to form a stable oxide coating on the inner wall of the cylinder. The steel cylinder processed by this method is used to fill with low content standard calibration gas, which can ensure long-term stability of the standard calibration gas.
Another example is the "t" and "to" inner wall special treatment technology developed by the Japanese oxygen company, which is also suitable for filling low content standard calibration gases. In recent years, China has developed special treatment technologies for the inner wall of gas cylinders, such as organic coatings on the inner wall of steel cylinders (such as fluororesin), which have advantages such as smooth inner surface, hydrophobicity, and corrosion resistance. This opens up a new way to maintain the stability of low-grade standard calibration gases. In order to reduce the reaction and adsorption between gas components and the inner wall of the container, the selection of cylinder materials is also very important. Through the study of the stability of standard calibration gases in steel cylinders made of different materials (such as carbon steel, aluminum alloy, and stainless steel), experiments have shown that using aluminum alloy steel cylinders to store Hubei standard gases is more effective. Wuhan ISOTOPE Technology Co., Ltd. Service hotline: 19526388246
