An extraction pump is a device that uses steam as the suction medium to achieve vacuum. Steam at a certain pressure is ejected at supersonic speed through a Laval nozzle, converting pressure energy into kinetic energy. At the nozzle exit, due to the entrainment effect of the high-speed steam flow, a low-pressure area is formed. The working steam and the suctioned gas flow are mixed in a mixing chamber and undergo energy exchange, with the mixed flow decelerating and pressurizing in the diffuser pipe. As the vacuum level requirements vary among users, each extraction pump can be configured with a single stage or multiple stages in series. The more stages, the higher the vacuum level (the lower the residual pressure).