Vacuum pump
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What is the difference between a jet pump and a water jet pump? ? What are their advantages and disadvantages, and is their principle the same?
The working medium in a water jet ejector is water, while that in a steam jet ejector is steam; both are used in vacuum systems to create the vacuum in condensers, and their structures are similar. However, jet ejectors generally require an installation height of more than ten meters. Compared with steam ejectors, jet ejectors not only share the advantages of compact structure, reliable operation, and easy maintenance like steam ejectors, but also offer the benefit of saving new steam used for the ejector, resulting in lower operating costs; moreover, there is no need to concern oneself with the steam source for the ejector before the turbine starts up. It facilitates the startup of high-power unit machines and can replace steam ejectors among other advantages. However, jet pumps require specialized water pumps, resulting in high investment costs. As steam parameters and unit capacity increase, water jet ejectors will be used more and more widely. The principle behind both is to use a high-speed stream of vapor or water ejected from a nozzle to draw air into the pressure chamber and then expel it.
The principle is the same. As a steam extraction device for turbines, from the perspective of energy utilization, steam extraction is more energy-efficient. In terms of current operating costs, Niijima is slightly more economical (this is related to the steam balance at each factory).
But the steam must be neutral and clean; otherwise, it will corrode the pipes and the shell side.