A dual-purpose gas cylinder is a liquefied gas packaging container that integrates a "liquid phase port+gas phase port" on the same cylinder. It can extract liquid from the bottom and gas from the top separately without moving, heating, or flipping the cylinder, achieving "one cylinder for two purposes". Dual purpose gas cylinders can be switched through valves, reducing labor intensity and avoiding the risk of liquid backflow. Widely applicable to various scenarios such as scientific research, semiconductors, healthcare, food, and industrial fuels. Used for metal cutting, glass processing, liquid phase for flame supply, gas phase for preheating; High purity CO ₂ or SF ₆, liquid phase for low-temperature cold trap, gas phase for chamber cleaning.