First, the overview of steam jet pump Steam jet pump is by virtue of the high-speed steam jet from the Laval nozzle to carry gas, it has the following characteristics: (1) The pump without mechanical movement, not Friction, lubrication, vibration and other conditions, it can be made pumping capacity of the pump. Reliable work, long service life. As long as the appropriate choice of structural materials pump for the exclusion of corrosive gases, gas containing mechanical impurities and water vapor and other occasions extremely favorable. (2) Simple structure, light weight, small footprint. (3) working steam pressure of 4 ~ 9 × 105Pa, in the general metallurgical, chemical, pharmaceutical and other enterprises have such a source of water vapor. Because of the above characteristics of steam jet pump, it is widely used in metallurgical, chemical, pharmaceutical, petroleum and food industries. Second, the principle of steam jet pump Jet pump by the nozzle and the diffuser and mixing chamber connected to form. Working nozzle and diffuser these two components form a special section of gas flow pipe changes. Air flow through the nozzle can be pressure energy into kinetic energy. The pressure difference between the working vapor pressure P0 and the pump outlet pressure P4 causes the working steam to flow in the pipe. In this particular pipe, steam passes through the nozzle outlet to this area (mixing chamber) between the diffuser inlet and a negative pressure area appears due to the high velocity of the steam flow. The negative pressure here is much lower than the working vapor pressure P0 and backpressure P4. At this moment, the sucked gas is sucked into the mixing chamber, the working steam and the sucked gas are intermixed with each other for energy exchange, the working steam is transferred to the sucked gas by the kinetic energy transformed by the pressure energy, the mixed gas flow is diffused in a certain section (Figure 3, section 3 '), the mixed gas flow velocity after the wave reduced to subsonic ω'3, mixed gas flow pressure rose to P'3. Subsonic airflow is decelerated and pressurized while the diffuser is expanding. Mixed gas flow in the diffuser exit, the pressure increased to P4, the speed dropped to ω4. Jet pump is also a gas compressor.