Air contains 21% oxygen, which reacts with ferrous and other metals.
Oxygen in installations therefore causes corrosion, and in effect contaminates the system. The problems mount and system efficiency declines.
The reaction between iron, water and oxygen is as follows:
O2 + Fe + 2H2O > Fe(OH)2 + H2
3Fe(OH)2 > Fe3O4 + H2 + 2H2O
This reaction creates the iron oxide magnetite (Fe3O4). In the continued presence of oxygen, this magnetite is converted into the much more voluminous haematite, Fe2O3:
4Fe3O4 + O2 > 6Fe2O3
This conversion irrevocably leads to the dreaded pitting corrosion in all kinds of locations in the system. Even though the ingress of air and the oxygen-related corrosion can never be fully prevented, the adverse effects of the corrosion products certainly can.
Corrosion particles are attracted to the magnetic fields in pumps, air valves and control valves. Other particles are pumped through the installation and eventually gather in critical components which results in unnecessary energy consumption and recurring complaints, such as reduced functionality, malfunctions and failure.
Contamination in heating or cooling installations largely consists of magnetite. The particles are so small that we cannot see them with the naked eye. The human eye sees things from about 10 µm; a human hair is about 40 µm wide. In contrast, the smallest magnetite particles are only about 5-10 µm in size, or five to ten thousandths of a millimetre. These particles cause the biggest problems, becoming attached in locations where a magnetic field is present, for example in valves, heat exchangers, pipes, radiators, pumps and calorimeters. This leads to a reduced installation performance and therefore to higher costs.
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