Over the last 20 years, the technology of cooling water deposit control has advanced significantly. There are presently numerous different deposit control agents available that are used to prevent the formation of the various scales and foulants discussed in the previous section.

Most today’s antiscalents are working under the “non stoichiometric model”. This means that there is not a precise mole to mole chemical reaction between the antiscalents and the scaling substances.

So a molecule of the chemical is controlling many thousand or even million of moles of p.e. Calcium, competing alkalinity, sulfates or silica, and avoiding the formation of the scale.

Prior to discussing the actual composition of these materials, it is necessary to understand the different mechanisms by which these materials function.

In general, cooling water deposit control agents function via one or more of the following mechanisms:

§         threshold inhibition

§         scale crystal distortion,

§         sequestration,

for scale inhibition, and

§         flocculation

§         dispersion, and

§         surfactancy.

for fouling control.

Since many of the materials that function via these mechanisms are polymers, we will first develop differences between the various types that exist.