Syringes can also be used to inject through rubber septa in medical devices, containers, and scientific instruments such as some chromatographies. Injecting gas into a blood vessel will cause an air embolism. Remove air from a syringe to avoid embolism by turning the syringe upside down, tapping it gently, and squeezing out a little fluid before injecting into the bloodstream

Due to the high precision of micro-mold surface processing, when the mold is closed, the gap between the movable mold and the fixed mold is extremely small, and the residual air in the cavity and the gas released from the melt are difficult to discharge from the cavity gap, affecting the molding quality of the product. and melt filling rate, micro molds are usually designed with vacuum exhaust systems. At present, the vacuum exhaust method mainly involves sealing around the mold cavity, opening an exhaust channel on the parting surface, and then using a vacuum pump to extract the gas from the mold cavity.