Rely on a certain pressure of the working fluid through the nozzle high-speed jet pump away the fluid being delivered. The picture shows the working principle of the jet pump. When the working fluid Qo is ejected from the nozzle at a high speed, the surrounding air is entrained by the jet at the entrance of the throat to be vacuumed, so that the delivered fluid QS is sucked in. The two fluids are mixed in the throat and exchanged for momentum, which increases the kinetic energy of the fluid being transported and finally converts most of the kinetic energy into pressure energy through the diffuser. In 1852, Britain's D. Thompson first used a jet pump as an experimental device to remove water and air. Since the 1930s, jet pumps started to develop rapidly. According to the type of working fluid jet pump can be divided into liquid jet pump and gas jet pump, of which water jet and steam jet pump is most commonly used. Jet pump is mainly used for conveying liquids, gases and solids. It also forms a deep well jet pump unit for water supply with a centrifugal pump. A centrifugal pump on the ground supplies a submerged jet pump that draws well water as a working fluid. Jet mud pump for river dredging, underwater excavation and underground mud. Jet pump without moving working elements, simple structure, reliable work, no leakage, do not require specialized personnel custody, it is very suitable for underwater and dangerous special occasions. In addition, it can also use pressurized wastewater, waste gas (gas) as a working fluid to save energy. Although the efficiency of jet pumps is generally not more than 30%, the efficiency of newly developed multi-jet, multi-jet and pulse jet pumps has been enhanced.