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Structure and characteristics of steam ejectors

2022-02-09


Steam ejector is a vacuum equipment with simple structure and stable performance. With the advancement of science and technology, its structural design is more and more suitable for the development of industry. Let's take a look at the structure and characteristics of steam ejectors.
  
A steam ejector is a vacuum pump with a certain pressure. The steam passes through the Laval nozzle, the pressure decreases and the speed increases. The potential energy of the steam is converted into kinetic energy, which is sprayed into the mixing chamber at supersonic speed. It is mixed with the pumping medium for energy exchange. The gas mixture enters the diffuser, decelerates and boosts, and is converted into pressure energy. In order to reduce the pumping load of the backing pump, it is equipped with a condenser, and the heat exchange is carried out by the convection of two media with a certain temperature difference to achieve the purpose of condensing the high-temperature medium.
  
Although the steam ejector has a simple structure, low operating wear, low material requirements and small maintenance. However, the working steam requirements are high, and the steam consumption is relatively large.
  
The internal components of the steam ejector consist mainly of a Laval nozzle and a diffuser. The structure of the single-stage steam ejector is shown in the figure, and the structural form of the other stages is basically the same. The working process can be divided into three stages: adiabatic expansion stage, mixing stage and compression stage.
  
1. In the adiabatic expansion stage, after the working steam passes through the scaling nozzle, the pressure energy is converted into velocity energy and enters the diffuser at a very high speed. At the same time, the pressure of the working steam drops at the outlet of the nozzle, creating a vacuum to suck in the pumped gas.
  
2. In the mixing stage, the pumped gas enters the diffuser. In a diffuser, steam collides with the pumped gas and mixes, exchanges energy, and mixes at the throat of the diffuser until both gases reach the same speed.
  
3. In the compression stage, after passing through the throat of the diffuser, the speed of the mixed gas decreases and the pressure increases further. When the outlet of the diffuser reaches atmospheric pressure or the inlet pressure of the next syringe, the pumped gas is discharged.
  
Common faults in steam ejectors
  
1. Nozzle blockage: the nozzle is blocked by large particles of foreign matter in the pipeline, resulting in the vacuum cannot be pulled;
  
2. Nozzle wear: After the nozzle is worn, the speed of steam entering the vacuum pump becomes slower, which affects the vacuum effect.
  
The working principle of the steam ejector is relatively simple, the user can choose the product they need by understanding its working principle, and the manufacturer can improve the shortcomings of this product and enhance the competitiveness of the product from its working principle.
  
In general, with the continuous improvement of China's industrial level, it is necessary to improve the competitiveness and market share of products. After years of development, the steam ejector has a very solid foundation. It is believed that with the continuous increase of market demand, steam ejectors will have a more brilliant future.

 

 

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