Water Purity Requirements
8.0WATER PURITY REQUIREMENTS
To ensure the maximum service life of the air/water heat exchangers, water must comply with the VGB water regulations
The following table contains the most important impurities and methods for removing them.
Table 4 | Prevalent impurities and removal methods |
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Water Impurity | Method of Removal | |
Mechanical | Filtering the water | |
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Excessive hardness | Soften the water using ion exchange | |
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| |
Moderate content of mechanical impurities and hardness formers | Addition of dispersing or stabilizing agents | |
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Moderate content of chemical impurities | Addition of passivation agents and inhibitors | |
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| |
Biological impurities (bacteria and algae) | Addition of biocides | |
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It is recommended to achieve the following hydrological data as far as possible:
Table 5 | Suggested hydrologic levels |
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Hydrological Data |
| Suggested | Units | |
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|
| Amount |
|
pH values |
|
| 7 - 8.5 |
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|
|
|
| |
Carbonate hardness |
| >3 <8 | °dH | |
|
|
|
| |
Free carbon dioxide |
| 8 - 15 | mg/dm3 | |
Bound carbon dioxide |
| 8 - 15 | mg/dm3 | |
Aggressive carbon dioxide |
| 0 | mg/dm3 | |
Sulfides |
|
| < 10 | mg/dm3 |
Oxygen |
|
| < 50 | mg/dm3 |
Chloride ions |
| < 250 | mg/dm3 | |
Sulfate ions |
|
| < 10 | mg/dm3 |
Nitrates and nitrides |
| < 7 | mg/dm3 | |
CSB |
|
| < 5 | mg/dm3 |
Ammonia |
|
| < 5 | mg/dm3 |
Iron |
|
| < 0.2 | mg/dm3 |
Manganese |
|
| < 0.2 | mg/dm3 |
Conductivity |
| < 2200 | μS/cm | |
|
|
|
| |
Solid evaporation residue |
| < 500 | mg/dm3 | |
Potassium permanganate consumption |
| < 25 | mg/dm3 | |
Suspended matter |
| < 3 | mg/dm3 | |
(Partial flow cleaning is recommended) |
| > 3 < 15 | mg/dm3 | |
| (Continuous cleaning) |
| > 15 | mg/dm3 |
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