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Lime scale washed out from a closed cooling loop


Company: Hengstenberg, Germany

Sauerkraut and other food are packed in canes. This canning machine needs a constant cooling. As feed water, untreated bore well water is used, which in this case has a lot of calcium solved. This calcium leads to the known problems of clogging of surfaces and pipes. A clogged or almost close system reduces the flow of water as well the heat transfer from the water to the machine. This finally reduces the capacity of cooling. To minimize the effects of the calcium, the water in the cooling loop was constantly replaced or blew down. In order to hold the concentration of the calcium in the cooling water as low as possible, at best case under the saturation point, where the calcium starts to fall out of the water and starts to crystalline and form incrustations.

This has lead to replacing of the app. 90m3 fresh water per day.
One Pursanova TM was installed at this open cooling loop. Pursanova TM is increasing the solubility of the calcium inside the water. The result the concentration of calcium in the water can be far higher until the calcium starts to build scale.

Short after the installation of Pursanova TM, a lot of calcium was automatically washed out of the system. This can be seen in the pictures below, where the drain was opened and a lot of sedimented scales was washed out. In the sedimentation tank, a lot of sludge was found. This sludge could be easily drained from the system.

After the self-cleaning of the system, the set value of the conductivity where the water was automatically replaced was step by step increased. Parallel the cooling capacity of the system was checked. It was found, there is almost no need anymore, to replace the water in the cooling loop. In other words, the COC has been increased from around 1 to nowadays more then 20.

Today, there are added only 8 to 10m3 of fresh water. This is mostly the amount which evaporates per day, and a little to do very moderate blowdown, compared to what has been needed before. So the client saves app. 80m3 water per day.