It is often called a vacuum filling machine. This filling method is to make the storage box at normal pressure. During filling, only the air in the bottle is pumped to form a vacuum. When a certain vacuum is reached, the liquid flows in by the pressure difference between the filling box and the container. In the bottle, the filling is completed. It is mainly used for filling non-gas liquids, such as juices. Because the filling is under vacuum, the filling is stopped when the bottle or can is leaked, which can reduce the loss. However, under vacuum, for some aromatic liquids, some fragrance will be lost. The negative pressure filling method has strict requirements on the bottle specifications, because its quantitative is determined by the depth of the filling nozzle into the bottle, and the volume of the bottle directly affects Quantitative accuracy. However, it is still widely used due to easy adjustment.