The main reason for plate crackdown
Plate heat exchanger is an important part of the refrigeration host, it is composed of a group of corrugated metal plate, the plate has four corner holes, for heat transfer of two kinds of liquid through, guide fluid alternately through the respective channel, heat exchange, they are closely arranged, high precision, small volume, high heat exchange efficiency, space saving, the use of environmental requirements is higher, suitable for use in small refrigeration units. General air conditioning equipment can be used for 15 to 20 years under normal maintenance, but the plate heat exchanger of the main engine is broken down, the main reasons are analyzed as follows:
1. Maintenance problems
Plate heat exchanger after a long time of operation, need regular cleaning, generally two years cleaning once. Such as the current plate heat exchanger can be taken apart to separate cleaning, but the plate heat exchanger on the main engine of the general refrigeration engineering can not be taken apart, can only be cleaned by opening the valve and wire plug on the inlet and outlet pipes of the heat exchanger, so the heat exchanger is difficult to clean, it is easy to block, scale, once a part of the heat exchanger channel is blocked, The remaining channels have to bear the flow of all the water in the unit. In this way, the increase of the flow rate through the plate heat exchanger increases the friction and the wear.
2. Board material change problem
Compared with the heat exchange surface of other heat exchangers, the heat exchange surface of plate heat exchanger is quite thin, that is, 0.5mm, and the maximum corrosion allowed is 0.05mm/ year. The material of ordinary plate heat exchanger usually uses alloy material (304 or 316). 304 is one of the cheapest austenitic stainless steel. It has corrosion resistance to a certain range of organic matter, but the resistance to hydrochloric acid and sulfuric acid is weak. General air conditioning host plate heat exchanger material is 304, so after 8 years, the plate will breakdown, corrosion is inevitable.
3. Installation problems
Only "Y" type filter is installed in the system, and no electronic water treatment device is installed, so it is difficult to ensure that the piping system is free of scale. In addition, if the "Y" type filter is not cleaned in time, there is still a residue in the circulating water, even if it is a small gravel that is basically not harmful to shell and tube heat exchanger, it will also be harmful to plate heat exchanger wear.
4, plate for plate processing technology
Plate heat exchanger plate processing technology is not scientific, the whole plate wall thickness is not uniform, normal use on the thinnest prone to perforation phenomenon.
5, the use of ambient temperature
The ambient temperature of plate heat exchanger is too low, the breakdown of plate is frozen, the content of plate exchange is small, the structure has too much expansion room, a frozen will be broken.
6. The problem of water quality under working conditions
At present, there is no denying the poor water quality of plate heat exchanger, and most of them have not been purified, filtration treatment, scaling, corrosion is common. Lead to plate heat exchanger plate is more prone to perforation. Other atypical causes such as water hammer and collision are not mentioned.
About the cause of plate heat exchanger plate breakdown, do you think there are other reasons, please feel free to say your opinion in the comment section below.
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Know the cold and the heat
Add 3 main causes of plate damage:
1. Tap water, as a chlorine-containing agent for sterilization, is the main culprit of pitting corrosion.
2. Thermal stress crack. It is concentrated in the area near the inlet of primary network heat source. The higher the temperature is, the farther the crack area is.
3. More than 99% of the 304 plates are not chemically passivated film (matte, silver. Reference to the color of aluminum alloy doors and Windows), pitting corrosion formed by potential difference corrosion under iron oxide scale, the speed is dozens of times that of chemical corrosion.
Avanti Avanti
Two more things to add,
1. There are many cases in pipeline welding where the heat exchanger is used as a link wire current to break down the heat exchanger plate.
2. The hard particle impurities in the medium will also break down the plate
Thank you for the two friends of the Zhi Leng Zhi hot, Avanti selfless sharing! Welcome more friends to share, let's make progress together.
The term of heat exchange plate is explained
Heat transfer plate: for pressing corrugated, sealed groove and corner hole metal sheet, is an important heat transfer element. Corrugations can not only strengthen heat transfer, but also increase the rigidity of the thin plate, thus improving the pressure capacity of the plate heat exchanger, and because the liquid is turbulent, it can reduce the formation of sediment or dirt, and play a certain "self-cleaning" role.
