1, the steam ejector pump
Steam jet pump is a single-stage steam ejector, steam at high pressure to work 1000 ~ 1400m / s high speed from the nozzle. In the course of the injection pressure of the steam energy into kinetic energy to generate a low pressure, the gas inhalation. Gas mixed with the steam sucked into the diffuser tube, the speed is gradually decreased. Pressure will be increased, and then discharged from the outlet pressure.
Advantage of the jet pump is pumping a maximum wide range of operating pressure, simple structure, no moving parts, easy to manufacture, adaptable (smokeable contain dust and corrosive, flammable, explosive gas, etc.); its main drawback steam consumption is large, inefficient, only 10% to 25%. Therefore, the jet pump is generally not used for the transmission of gas, but more for vacuuming often called the jet pump.
In addition, the steam jet pump is also often used as a small boiler water filter, so that both the steam boiler water itself, but also the heat recovery steam is an effective energy-saving measures.
Single-stage steam ejector, generally produce an absolute pressure of about 0.01MPa for low pressure, i.e., resulting in a degree of vacuum of about 90%. To get a higher degree of vacuum can be multi-stage ejector. Such as refinery vacuum distillation tower is often used three or four steam ejectors, can produce absolute pressure or low pressure 550Pa about 40Pa.there also have steam ejector system can be used.
2, the water jet vacuum pump
In the actual production, when the degree of vacuum requirements are not too high, water under pressure can also be used as a working fluid water jet pump creates a vacuum. Water velocity usually 15 ~ 20m / s, generally only generate a low pressure of about 8kPa, efficiency is usually 30% or less. However, due to its simple structure, not only to create a vacuum, but also the condensed steam, it is widely used in a vacuum evaporation apparatus, both as a condenser and as a vacuum pump, so often called water jet condenser.