Valve bags, commonly known as pinch-bottom bags, are fed from the top or bottom valve port and use special filling equipment to automatically form a rectangular parallelepiped after filling. They have the characteristics of efficient filling, neat stacking, firmness and reliability, convenient transportation, and beautiful appearance. They are widely used in the packaging of powdered or granular solid materials and flexible items such as edible powder, chemical powder, fertilizer, synthetic materials, medicine, and minerals. Super-sized valve bags are widely used in the meteorological silica industry and the packaging of ultra-fine nano-level powders. They are currently the mainstream environmentally friendly packaging bags in the world.