Development of a unit suitable for corrosion monitoring in district heating systems. Experiences with the LOCOR-cell test method

A by-pass unit suitable for placement of a number of different probes for corrosion monitoring has been designed. Also measurements of water parameters are allowed in a side stream from the unit. The project is a part of the Nordic Innovation Fund project KORMOF. The by-pass unit has been installed in 6 pressurised circulating heating systems and in one cooling system. 7 different corrosion monitoring methods have been used to study corrosion rates and types in dependency of water chemistry.

This paper describes the design of the by-pass unit including water analysis methods. It also describes the purpose, background and gained results of one of the used monitoring techniques, the crevice corrosion measurements obtained by the LOCOR-Cell„§. The crevice corrosion cell was developed by FORCE Technology in a previous district heating project financed by Nordic Industrial Fund (1)(2).

Results from other used corrosion monitoring methods in the project are described elsewhere (3) and (4). For future district heating corrosion monitoring the by-pass unit can be recommended for permanent installation and the two methods high sensitive ER-technique (Metricorr) and the LOCOR-Cell㤠(FORCE Technology) are found very useful.