Zeta Rod™ science & technology

Many of the problems associated with water systems such as scaling, corrosion, and biofouling are largely governed by interactions between materials suspended in the water and the wetted surfaces of the system.

The Zeta Rod works by altering the natural surface charge of suspended particles. The results of this fundamental physical alteration are profound: particles that would normally stick to surfaces or agglomerate into scale or biofilms remain separated in stable suspension.

The stability of the suspension is enahnced by increased electrostatic repulsion between particles due to the "double layer" of ions that surround particles and wetted surfaces.

[Read "Fouling Mitigation in Aqueous Systems Using Electrochemical Water Treatment" for a detailed discussion of the double layer, and applications to heat exchangers.]

The formation of the double layer is shown in the figure below. In the illustration below the particle (blue) is shown to have a net negative surface charge. The particle is surrounded by a layer of ions (red) that remain tightly bound to the particle surface.

The bound layer is in turn surrounded by a layer (light blue) that is much more diffuse and is not tightly bound. Forces acting upon the particle can cause distortion or separation of the particle from the diffuse layer at the "shear plane" but the tightly-bound layer is considered to remain attached to the particle as it moves.

Particles exposed to the powerful electrostatic field of the Zeta Rod electrode experience an elevation in surface charge that increases the density of the bound layer. The stronger bound layer serves to prevent the approach of the charged particles to each other.

Wetted surfaces also form a strong bound layer, which prevents particles from attaching. The cleanliness of wetted surfaces preserves heat transfer efficiency and interferes with the metabolic processes that lead to biofouling by microorganisms.

Zeta Rod electrodes are designed to generate the powerful field required to ensure stable particle dispersion in a wide variety of applications.