The selection of packaging container materials and the processing technology of the inner wall of packaging containers are crucial for maintaining the basic composition content of VOC standard gases and mixed gases unchanged in the long term. 

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 the concentration change of gas components in steel cylinders are as follows: chemical reactions between gas components and the inner wall material of the cylinder; Gas components are adsorbed onto the inner wall of the cylinder; The gas components react or dissolve with the remaining water vapor in the bottle and are absorbed in water; The inner wall of a steel cylinder adsorbs impurities and gas desorption components. Due to the above reasons, strict inner wall treatment must be carried out before filling steel cylinders with VOC standard gas mixtures. The common processing methods include: polishing the inner wall of the steel cylinder; Galvanize the inner wall of the steel cylinder (such as galvanized, nickel, chromium, copper, gold, etc.); Phosphate treatment of the inner wall of the steel cylinder; Chemical coatings on the inner wall of steel cylinders, etc. 

According to Japanese patents, new methods for processing the inner wall of steel cylinders are constantly emerging. After pickling and emptying, oxygen or oxygen-containing gas is injected into the inner wall of the cylinder to form a stable oxide coating. The steel cylinder processed by this method is used to fill low standard calibration gas, which can maintain the long-term stability of the standard calibration gas. 

For example, a Japanese oxygen company has developed special treatment technologies for the inner walls of T and TO, which are also suitable for filling low concentration standard calibration gases. 

In recent years, China has developed special treatment technologies for the inner wall of gas cylinders, such as applying organic coatings (such as fluororesin) on the inner wall of steel cylinders, which have advantages such as smooth inner surface, hydrophobicity, and corrosion resistance. It opens up a new way to maintain low concentration standard calibration gases. 

In order to reduce the reaction and adsorption between gas components and the inner wall of the storage tank, the selection of steel cylinder materials is also very important. 

Wuhan ISOTOPE Technology Co., Ltd. Service hotline: 19526388246