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Key points for the use of steam ejectors

2021-12-20


Steam ejector is a kind of vacuum acquisition equipment with simple structure and stable and reliable performance, which is widely used in vacuum evaporation, distillation, rectification, sublimation, drying, crystallization, concentration, deodorization, decolorization, dehydration, filtration, material vacuum transportation, chemical absorption, degassing, etc. Petroleum, chemical, oil, pharmaceutical, metallurgy, light industry, textile, food, sugar, salt and other industries.
  
Low steam pressure and pressure fluctuations have a great influence on the capacity of the steam ejector vacuum pump, so the steam pressure should not be lower than the required working pressure, but the structural design of the vacuum pump used has been finalized, and the excessive increase in steam pressure will not increase the pumping capacity and vacuum degree. In addition, in order to ensure the stability of the steam pressure supplied by the boiler, try to use the boiler to provide working steam for the steam jet pump, so that the steam pressure will not fluctuate and the performance of the vacuum pump will be stable.
  
The dryness of the steam also has a great influence on the performance of the steam ejector vacuum pump, and the moisture content in it will cause vacuum fluctuations, even if there is too much water, it cannot withstand the vacuum. It is common practice to install a separator in front of the steam drum to obtain a higher degree of working steam and to effectively insulate the steam pipes. In order to get better working efficiency, the working steam of the jet vacuum pump should be 5 ~ 10 superheated steam. Especially for fifth-stage pumps, the quality of the steam is very demanding, and micro-moisture may cause nozzle ice plugs, causing the vacuum level of the five-stage ejector to drop or not work.
  
If the cooling water supply is insufficient, the condenser of the steam ejector will become hot, the air flow will become larger, the vacuum level will drop rapidly, and even the steam will flow back to the exhaust pipe. For the inter-pipe cooling condenser, the water supply pressure should be between 0 and 2MPa, and the water supply should be slightly greater than the actual consumption, so that the fluctuation of water consumption will be relatively stable. In addition, in order to avoid vacuum fluctuations caused by unstable water supply, Zhonghuan Vacuum Pump believes that it is best to use a separate circulating water system to supply water to the condenser of the vacuum pump.
  
If the cooling water temperature is too high, the capacity of the steam ejector vacuum pump will decrease, and sometimes even the vacuum cannot be pumped, generally not exceeding 32. In addition, the higher the cooling water temperature, the more steam is consumed.
  
The influence of cooling water quality on the capacity of the vacuum pump of the steam ejector is also a factor that cannot be ignored. If the water quality is poor and the hardness is high, the condenser will scale or even block, seriously affecting the heat exchange performance, making it difficult for the steam to condense, thereby affecting the vacuum degree. Therefore, the circulating cooling water should be guaranteed to be pure demineralized water.
  
When the steam ejector vacuum pump is in the limit state, the first stage discharges little or sometimes no water, therefore, the first stage pump discharges a large amount of water, which can be considered a system leak. Common causes of air leakage are: gaskets not installed, incorrect or damaged installation, untightened bolts, damaged flange surfaces, trachoma in welds, joints (pressure gauges, vacuum gauges, etc.).

 

 

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