Why does a refrigeration unit need to be evacuated
When it comes to vacuuming, what is vacuum?
In fact, vacuum is a spatial state where no matter exists at all, and it is a physical phenomenon. For refrigeration equipment, vacuuming is an indispensable and crucial process before charging refrigerants during production, installation, and maintenance. It can extract the air from the refrigeration equipment and pipelines. However, the air contains a large amount of impurities such as nitrogen, oxygen, and water vapor, which can cause harm to the operation of our refrigeration equipment. The specific analysis is as follows.
I. The Impact of Nitrogen on Refrigeration Systems
Nitrogen is a non-condensable gas. The so-called non-condensable gas refers to a gas that circulates with the refrigerant in the system, does not condense along with the refrigerant, and does not produce a refrigeration effect.
The presence of non-condensable gases poses a significant threat to refrigeration systems, mainly manifested in the increase of condensing pressure, condensing temperature, exhaust temperature of the compressor, and increased power consumption. When nitrogen enters the evaporator, it cannot evaporate along with the refrigerant and will also occupy the heat exchange area of the evaporator, preventing the refrigerant from fully evaporating and reducing the refrigeration efficiency. At the same time, excessively high exhaust temperature may cause the lubricating oil to carbonize, affecting the lubrication effect. In severe cases, it may even burn out the motor of the refrigeration compressor.
Ii. The Impact of Oxygen on Refrigeration Systems
Oxygen, like nitrogen, is also a non-condensable gas. We have already analyzed the hazards of non-condensable gases above, so we will not repeat them here. However, it is worth noting that compared with nitrogen, if oxygen enters the refrigeration system, it also has the following hazards:
Chemical reactions produce impurities
Oxygen in the air will undergo a chemical reaction with the refrigeration oil in the refrigeration system to generate organic matter, which eventually forms impurities and enters the refrigeration system, causing adverse consequences such as dirt blockage.
Acidic substances are produced to damage the components
Oxygen is prone to acidic chemical reactions with refrigerants and water vapor impurities, causing oxidation of the refrigeration oil. These acidic substances can damage the various components of the refrigeration system and destroy the insulation layer of the motor. At the same time, these acid products will remain in the refrigeration system. Initially, there may be no problem, but over time, it may eventually lead to the damage of the compressor.
Iii. The Influence of Other water vapor Impurities on the Refrigeration System
Water vapor affects the normal operation of the refrigeration system. The most direct impacts on the refrigeration system are as follows. Let's explain them in the form of pictures and text
An ice blockage fault occurred
When there is water in the refrigeration system, the first impact is on the throttling structure. When water vapor enters the throttling mechanism, the temperature drops rapidly. The water reaches the freezing point and freezes, blocking the tiny through holes of the throttling structure and causing an ice blockage fault.
Produce sludge deposits
During the compression process of the compressor, water vapor, when encountering high temperatures and substances such as refrigeration oil, refrigerant, and organic matter, can cause damage to the motor windings, metal corrosion, and the formation of sludge deposits.
In conclusion, in order to ensure the effectiveness of the refrigeration equipment, extend its service life, and guarantee that there are no non-condensable gases in the refrigeration equipment, it is necessary to evacuate the refrigeration system.
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