DEMKOR protects your aluminium hot water boiler and your piping system

KORN offers an integrated solution for the safe and efficient operation of hot water systems with aluminium heat exchangers and connected piping systems made of steel and other non-ferrous metals.

Until now, the focus has always been on protecting the supposedly most expensive component of a hot water system: the aluminium heat exchanger installed in the hot water boiler.

Accordingly, the pH values of the boiler water in the pipe system were usually only adjusted to this aluminium heat exchanger. The often very complex pipe system connected to it was therefore not taken into account.

The protection of the complex piping system was therefore rather neglected in the past. However, repairing a defective piping system is associated with extremely high costs and long downtimes.


Fig. 1; Research results using EIS measurements (electrochemical impedance spectroscopy) with proven optimum corrosion protection in the pH value range between 8.0 and 9.0 for aluminium and steel.

Source: R. Gaudreault, M. Dargahi; TGWT Inc.

DEMKOR 61: Corrosion inhibition efficiency for aluminium and steel in one system

In addition to their high oxygen-binding properties, the purified tannins of DEMKOR 61 offer optimum corrosion protection for steel and aluminium in an overlapping pH range.

This is demonstrated by the research results shown in Fig. 1 using EIS measurements (electrochemical impedance spectroscopy).

DEMKOR 61: Prevents corrosion in an extended pH range

The current technical water value guidelines for the protection of the various metals contain a conflict between the desired pH values for hybrid systems (which consist of aluminium as well as steel and non-ferrous metals). Despite contradictory technical guidelines, these hybrid systems are the rule today, not the exception.

What use is the best protection for your aluminium heat exchanger if the other components of the piping system are made of steel and other non-ferrous metals and these are attacked or even destroyed by corrosion due to incompatible pH values?

The use of our tannin-based product DEMKOR 61 enables an overlapping of the pH value ranges at pH 8.0 to pH 9.0 with a good corrosion protection effect on all contained components including the aluminium heat exchangers and the piping system made of steel and non-ferrous metals.

With 40 years of experience in steam boiler plants, district heating networks and hot water plants, KORN has an extraordinary application knowledge which we put at the service of our customers with pleasure and passion.


Your DEMKOR advantages at a glance

  • Optimum corrosion protection in compatible pH value range

  • Protects the high investment costs in the piping system

  • Excellent oxygen-scavenging properties

  • High corrosion-inhibiting efficiency due to formation of an iron tannate layer

  • Optimum reduction of corrosion in aluminium and non-ferrous metals in one system

  • Tannin based product

  • non-toxic and 100% ecological

  • Manufactured from renewable raw materials

Extended pH range for aluminium and steel

Manufacturer’s guidelines Tannin-based water treatment
Values Aluminum Mild Steel Aluminum & Mild Steel
pH 6,5 – 8,5 9,0 – 10,5 8,0 – 9,0
Conductivity < 3000 μS/cm DEMKOR 61 dosed
Alkalinity 6 mmol/L
Aluminum < 3 mg/L
Mild Steel < 20 mg/L
Copper < 3 mg/L
Chlorids < 100 mg/L
Hardness < 0,02 mmol/L

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