# Development of a Gas Mixing System for Controlled Atmosphere(CA) Chambers

• Yun, Hong-Sun (National Agricultural Mechanization Research Institute, Suwon) ;
• Lee, Hyun-Dong (National Agricultural Mechanization Research Institute, Suwon) ;
• Lee, Won-Ock (National Agricultural Mechanization Research Institute, Suwon) ;
• Chung, Hun (National Agricultural Mechanization Research Institute, Suwon) ;
• Cho, Kwang-Hwan (National Agricultural Mechanization Research Institute, Suwon)
• Published : 2001.06.01

#### Abstract

Based on the viscous flow characteristics of gas through capillary tube, a simple and cheap gas mixing system was developed for controlling gas compositions in CA chambers. The gas flow rate through capillary tube had a linear relationship with pressure, (length)$^{-1}$ and (radius)$^4$ of capillary tube, which agreed well with Hagen-Poiseuille’s law. The relationship between flow rate and combined parameters was described as Q=0.000209724($\pi$ r$^4$P/$\mu$L) and the coefficient of determination was 0.9984. The developed system could control gas concentrations in CA chambers within $\pm$0.3% deviation compared to the preset concentrations. It was possible to predict the required time and required gas flow rate for exchanging the gs in CA chamber to a certain concentration of gas by using the mathematical model developed in this study.