Environmentally Friendly Corrosion Protection For Machines: Good Cooling Water Quality Without Chemicals

For good production results and low service costs, a permanently high water quality is required. Users must ensure that their machines do not allow bacteria to form in their circuits, which are disturbed by biofilms, for example – or where corrosion often gnaws at steel moulds. Corrosive or bacterially contaminated cooling water damages machines and plants, especially in plastics processing companies.

Chemicals are often used to regulate the pH value and biocides to prevent the formation of biofilms to prevent or at least reduce corrosion in the plants. However, the use of these agents is also maintenance- and cost-intensive. A chemical-free solution is therefore ideal for maintaining the quality of the cooling water, which is not only associated with lower costs but also protects the environment.

A typical example is companies that use injection moulding systems, writes Christian Barth, Country Manager at Enwa AS in Hennef in the trade journal 'Plastverarbeiter'. There, he says, cooling circuits are used in which oxygen and CO2 always penetrate the water and reduce the pH value. The treatment of the tools can also subsequently deteriorate an initially good water quality in the cooling circuit. This happens when passivation is carried out with phosphoric acid and the rest of the highly concentrated acid is not properly rinsed out of the mould before the next use. When the mould is put into operation, this residue is then returned to the large circuit and harm  the water quality, but in practice, the situation is usually different for users of chemicals.

If chemical corrosion protection agents are added to the system to counteract corrosion, it is not uncommon for the biology in the storage tank to virtually explode. As a result, biocides are necessary to remove the bacteria – a vicious circle, so to speak.

A Solution Without Chemicals For Clean System Water In Cooling Circuits.

The consistent use of minerals means that no food source for bacteria can be created in the first place. The permanently high pH value, once set, in combination with the minerals, represents an effective bacterial barrier.

The corrosion protection is achieved by the adjusted pH value, which forms a stable protective layer on the base metals. The pH-value is self-regulating and enables maintenance intervals of twelve months for the operator.

The expert recommends the use of a pressurised, closed system for a new system to be planned. This would not automatically solve all the challenges of open systems, but the boundary conditions would be easier to control. However, this water is not bacteria-free - just as drinking water cannot be. And, corrosion often remains an issue, as many of the systems are made of steel.