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wikisis [2019/06/11 17:03] superman |
wikisis [2019/08/29 16:00] (current) superman [Why do Systems Corrode?] |
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| - | All the symptoms described above can be linked to one thing: They are caused by [[corrosion|corrosion]] and its associated effects. Corrosion comes in many forms and can be a very complex subject. In heating and cooling systems, the most common form by far is [[wiki:dokuwiki|Uniform Corrosion]] | + | All the symptoms described above can be linked to one thing: They are caused by [[corrosion|corrosion]] and its associated effects. Corrosion comes in many forms and can be a very complex subject. In heating and cooling systems, the most common form by far is Uniform Corrosion, also called General Corrosion. |
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| - | All systems containing metals such as steel, brass, copper etc. corrode. Low levels of corrosion in itself are not a problem. It only becomes a problem if there is continued or accelerated corrosion. There are a number of possible causes for continued or accelerated corrosion rates. Uniform corrosion, which is by far the most common form in heating systems, can only occur in the presence of [[https://en.wikipedia.org/wiki/Oxygen|oxygen]]. Simplified it can be said that the more oxygen is present in the system the higher the rate of corrosion.\\ | + | All systems containing metals such as steel, brass, copper etc. corrode. Low levels of corrosion in itself is not a problem. It only becomes a problem if there is continued or accelerated corrosion. There are a number of possible causes for continued or accelerated corrosion rates. Uniform corrosion, which is by far the most common form in non-chemically treated heating systems, can only occur in the presence of [[https://en.wikipedia.org/wiki/Oxygen|oxygen]]. Simplified it can be said that the more oxygen is present in the system the higher the rate of corrosion.\\ |
| - | <wrap em>Without oxygen, corrosion will stop.</wrap> Therefore it is vital to prevent oxygen from entering the system. | + | <wrap em>Without oxygen, corrosion will stop.</wrap> Therefore it is vital to prevent oxygen from entering the system.\\ |
| There are a number of ways oxygen can enter a system: | There are a number of ways oxygen can enter a system: | ||
| + | {{ :corrosion_triangle.png?300|}} | ||
| * **Dissolved in the initial fill or topping up water** | * **Dissolved in the initial fill or topping up water** | ||
| * **Trapped as air in the system after filling** | * **Trapped as air in the system after filling** | ||
| - | * **Diffusion through non-diffusion tight materials such as plastics and rubbers** | + | * **[[https://en.wikipedia.org/wiki/Diffusion|Diffusion]] through non-diffusion tight materials such as plastics and rubbers** |
| * **Low system pressure allowing air to be sucked in at high level** | * **Low system pressure allowing air to be sucked in at high level** | ||
| - | The amount of oxygen that enters the system and the corrosion that is caused by these mechanisms varies greatly. | + | The amount of oxygen that enters the system and therefore the corrosion that is caused by these mechanisms varies greatly. |
| - | [[Research]] has shown that incorrect [[pressurisation|pressure]] control leading to air being sucked into the system at high level leads by far to the most corrosion. How this happens is not immediately obvious and therefore often not identified as a cause of the corrosion. | + | Research has shown that incorrect [[pressurisation|pressure]] control leading to air being sucked into the system at high level leads by far to the most corrosion. How this happens is not immediately obvious and therefore often not identified as a cause of the corrosion. |
| In the majority of closed heating and cooling installations, an expansion vessel controls the pressure. | In the majority of closed heating and cooling installations, an expansion vessel controls the pressure. | ||
| - | It therefore follows that the expansion vessel plays a vital role in the fight against corrosion and the Sick Installation Syndrome. | + | It therefore follows that \\ |
| + | the expansion vessel plays a vital role in the fight against corrosion and the Sick Installation Syndrome. | ||
wikisis.1560265437.txt.gz · Last modified: 2019/06/11 17:03 by superman
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