Electrophysical wall drainage

Electrophysical wall drainage is called a method of wall drainage through the influence of electricity . The effectiveness in practical use is controversial and partly contradicts physical laws .

Procedure

The electrophysical wall dehumidification processes claim to reverse the movement of moisture in the direction. Active methods prevent water or moisture from "actively" penetrating the wall , passive methods are used when the water has already penetrated. A distinction is made here:

Procedure based on active electroosmosis (through the build-up of electrical fields via external voltage )
Procedure based on passive electroosmosis
- Earthing method (equalization of potential differences by introducing electrical conductors, probes or networks)
- Charge compensation process also known as the dipole process: "Elimination" of the wall's own electrical field through the installation of dipoles
- Galvanic process: Creation of a galvanic element in the masonry and associated with it an electrical potential
electromagnetic processes:
- Active radio technology: Allegedly stimulating the movement of the water molecules in fine building material capillaries, this should lead to charge separations between the capillary boundary layer and the water molecules, which are mostly bound to a hydration shell (salt ions), or by reversing the polarity of the dipoles of the water molecules.
- passive radio technology.

Active electrophysical processes are considered to be of limited use, passive electroosmosis and electromagnetic processes are considered controversial in the professional world, their effect is often questioned, they are often referred to as “magic boxes”.

Electro-osmotic processes

The methods are based on electro-osmotic flow, whereby a charge-induced movement of liquids along a phase boundary occurs in an electric field. In addition, by applying a minimal electrical extra-low voltage, a potential reversal of the plus and minus pole is brought about, whereby the direction of movement of the water molecules in the masonry capillaries should be reversed, i.e. the moisture should no longer rise, but should be pushed back into the ground.

Electromagnetic and magnetic processes

This controversial process attempts to generate suitable electrical fields by using electromagnetic effects in order to use them and / or magnetic fields to additionally influence properties of the water or electroosmosis, such as:

the surface tension (see also electrowetting ),
the alignment of the dipoles of the water (see polarization (electricity) and orientation polarization , explanatory models for alignment see here )
the evaporation behavior
the density
Nuclear spin changes of atomic nuclei according to the principle of nuclear magnetic resonance (whether weak electromagnetic or magnetic fields are sufficient for this is not sufficiently clear).

An operating principle called “magnetokinesis” is supposed to “absorb” magnetic fields of the earth's magnetic field, sometimes also called “earth force field”, to radiate them again with a changed frequency or polarization and thereby change an “ion flow of the water”. The underlying scientific mechanisms of action are not known.

In addition to the electrophysical processes, similar devices are also offered that “neutralize” or “deflect” earth rays that are responsible for moisture damage . There is no scientifically recognized evidence for the existence of the radiation itself or for its effects.

It would be wrong to assume that a process works because it has been patented or the inventor received an award. When a patent is granted, it is not assessed whether a process is successful, but only whether it is something new (not yet available on the market).

criticism

In contrast to brick building materials, the electroosmotic permeability of lime mortars has a negative sign, which means that the liquid flow there is in the opposite direction.
Masonry electrodes corrode under the influence of masonry salts, which among other things affects the efficiency, durability and functionality of such electrodes.
So far, it cannot be ruled out beyond any doubt whether calcium and silicon ions may also migrate to the electrode as a result of the stimulated migration of ions, which in the long term will lead to “dryness of the masonry mortar”.
At voltages above approx. 1.9 V, water electrolysis inevitably takes place, i. H. gas is generated inside the masonry.

literature

Ulrich Schneider: Drainage of components using electrical methods. In: Bauphysik-Kalender 2003. Ernst & Sohn, 2003, ISBN 3-433-01510-4 , ISSN 1617-2205 , pp. 647-691

Jürgen Weber, Volker Hafkesbrink: Building sealing in the renovation of old buildings - procedure and legal approach. Cape. 8 Physical procedures . Teubner Verlag, 2006. ISBN 978-3-519-00460-8 and from page 20 “Historical outline” (partially accessible with Google Books )
Paul Wieden: The dehumidification of masonry with special consideration of the electro-osmotic process . Civil engineering practice, No. 30, Verlag Wilhelm Enst & Sohn, Berlin, Munich, 1965.
Documentation Center for Structural Engineering Stuttgart: Compilation of literature: Electro-osmotic wall drying: 1965 - 1971; Erg. to N 901, N 1077, N 1344, edition 1740, Verlag Documentation Center for Structural Engineering in the Fraunhofer-Ges., 1972