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Filtration

Filtration in heat transfer/cooling systems is needed for three reasons:

1. The removal of any airborne particulates which are caught by the system, for example, dust, dirt, etc., being caught by the cooling tower and then re-circulated throughout the system. Such dust, dirt, etc., could readily plug heat exchanger tubes and flow channels.
2. The removal of existing scale in a system as the oxidation and polarization of the water softens and renders the existing hard scale on heat transfer surfaces clean.
3. The prevention of scale buildup on heat transfer surfaces, when a system is clean so that the normal precipitation and nucleation of solids which occurs from solution can be removed. The make-up water that replaces water lost in the backwash process contains minerals and sometimes chemicals, bacteria and viruses that add to the problem, which is then held in solution and removed by the specially designed filtration system in order to maintain the system free of scale and biofilm.

pH Control

pH CONTROL is important in minimizing the rate of corrosion in a heat transfer/cooling system.
The measure of the concentration of hydrogen ions present in a solution is critical. A pH= 7 reading means the solution is essentially neutral. To avoid corrosion problems, controlling the pH in an alkaline range of between 8 and 9 is important, however, when the pH is alkaline, there is a greater tendency towards scaling from dissolved solids. The ION Generation System also handles that problem in that it can effectively operate in higher pH while still inhibiting scale deposits. The Ion Generation System electronically monitors both the pH and conductivity levels within their control range providing continuous cleansing of the water resulting in a scale-free operation. Scale acts as a host substance upon and inside which algae and bacteria can grow and hide. Elimination of the scale removes the host substance and eliminates the possibility that biologicals in the water will cling to any surface on contact. The copper IONs generated by the System will kill the bacteria and algae and keep the residue in solution until it is trapped and removed by the filtration system.

Conductivity

Conductivity in heat transfer/cooling systems must be carefully controlled.

When the water conductivity reaches a set-point level, the system's electronic control system sends a signal to the ion generation electrode adjusting its ion output to increase the level of oxidation being induced into the water stream. The conductivity measurement is based on the level of TDS in the water which varies the electrical conductivity of the water and is used as the control parameter for the level of oxidation needed to clear the water. In a typical cooling tower application the control of conductivity ranging from between 1,000 to 1,200 microhms/cm will usually produce 3 to 4 cycles of concentration and control the cooling tower water adequately.

Corrosion

The presence and growth of micro-organisms in heat transfer/cooling systems cause plugged water passages and severe deterioration of metal surfaces by under-deposit corrosion.

Iron deposition and corrosion is caused by the metabolism of "iron bacteria", which can remove water soluble ferrous salts and deposit them as insoluble ferric oxides. These oxides tend to grow rapidly and can reach sizes large enough to restrict water flow. The ION Generation System kills the micro-organisms.

Another group of bacteria produce acids and waste which attack metal surfaces directly. These organisms can convert water-soluble sulfur compounds into hydrogen sulfide. One of the most common sulfate–reducing bacteria is desulfovibria. This bacterium uses organic nutrients from the decomposition of other bacteria or algae as food. This process often takes place under existing biofilm or scale deposits. The corrosive action of desulfovibrio can produce condenser tube penetration in as little as six weeks. A third group of corrosive bacteria common to cooling towers are know as nitrifying bacteria. The bacteria react with dissolved ammonia to produce nitric acid. This acid lowers pH and causes localized attack on both copper and steel. Lastly, algae, a major source of trouble in cooling tower water systems, adheres to metal surfaces and accelerates pitting by the release of oxygen during the metabolic process. Large algae growths also impede the effectiveness of biocidal treatments by absorbing them.