EP0612365B1 - Process and device for the elimination of humidity in the walls of a building - Google Patents

Abstract

Device for the elimination of humidity in the walls of a building, characterized by having a small number of electrodes (10, 48, 64) to be distributed in at least one wall (12, 50, 66) of said building (5, 60) at a height (h &cir& _-h &cir& _') of a few metres above ground level, a ground connection (16, 68) to be inserted in the ground and conducting wires (20, 22) for connecting each electrode (10, 48, 64) and the ground connection (16, 68) to connectors for a source of d.c. current (18), said electrodes and ground connection being respectively connected to pole (-) and to pole (+) of said source (18). The invention also concerns a process characterized in that a continuous electric circuit is established, with negative polarity being applied to the whole building (5, 60) and positive polarity being applied to a ground connection (16, 68).

Description

The present invention relates to methods for the removal of the humidity of the walls of buildings in particular in the case of constructions old. It relates more particularly to the fight against lifts moisture from the soil.

Rises in humidity in the walls are at the origin of numerous and significant degradations such as the appearance of cracks, blackish stains or the detachment of interior wall coverings, plaster or exterior cleaning, etc.

This phenomenon obviously affects mainly the old constructions which did not plan any preventive measure against this humidity. But it is also observed for constructions more recent in very humid regions.

To remedy this problem, we have known for a long time process of drying the walls of a building by electro-osmosis. This technique consists in implanting a series of electrodes in all the walls to be treated, in a horizontal plane and at a low height (approximately 30 centimeters) above ground level. These electrodes are connected between them and also to one or more earth connections. By use of specific materials for wall electrodes and for earth connections, an electric field of high intensity is created (several tens of millivolts per meter). Under the influence of this field, the water molecules which went up in the walls, due to cracking or porosity of constituent elements of the walls, are then subjected to a movement descending and are therefore driven back to the ground.

In addition to this so-called "passive" method, we also know a so-called "active" method which consists, as before, in implementing in damp walls, a series of electrodes at a low height from at ground level, as well as earth plugs in the ground. The difference is in the fact that a direct current source is provided to supply the installation. Also, the wall electrodes are connected to the positive pole of the current source and the earth point (s) are connected to the pole negative from this source.

A variant of this method has been described in document FR-A-1 583 464. It consists in introducing into the walls to be dried, two series of electrodes one above the other at predetermined distances, the electrodes being connected to each other by an electrical conductor for each of these series. The upper series is then connected to the positive pole of a direct current source and the lower series is connected to the negative pole. This variant eliminates the need for earth connections located in the ground.

Despite the high intensity field involved by these methods, the results obtained proved insufficient especially as it is necessary to wait several months to be able to observe a beginning of drying.

Subsequently, with the aim of improving the efficiency of the technique by electro-osmosis, the document FR-A-1 508 872 described the combination of method of drying by electro-osmosis with electrophoresis. For this make, phoresis products are introduced into the recesses made in the walls to implant the electrodes. Under the influence of the field electric applied simultaneously with the electro-osmosis phenomenon of water molecules, the ions from the phoresis products migrate in the direction of displacement of water. These products are therefore entrained in the capillaries of walls which are thus closed.

Various phoresis products have been described, in particular in the document FR-A-2 603 318, in liquid and / or powder form.

Nevertheless, although the results obtained by the coupling of electro-osmosis and electro-phoresis are significantly better than with electro-osmosis alone, they are not entirely satisfactory and often residual moisture remains.

In addition, these methods require the use of a very large number of electrodes, i.e. several hundred per wall, in order to create no step and as best as possible, a strong electric field, continuous and uniform, i.e. several hundred millivolts per meter over all the walls. This results in very high installation costs.

In addition, in most cases, it takes several months (at least minus 3 or 4 months) to start observing the disappearance of moisture and the installations must be checked, not only during their installation place but also during operation because their efficiency, already average when the humidity is very high, is not constant. In Indeed, it often happens that a certain number of electrodes must be quickly changed because they became totally ineffective due to from their oxidation or from an accumulation of derivatives of phoresis products.

We also know the process for treating the humidity of the walls which is described in US-A-3,523,884. This method essentially consists in establishing a electrical circuit in which the electrode of negative polarity, i.e. the cathode, is implanted in the construction while the polarity electrode positive, i.e. the anode, is implanted in the ground. However, with the circuit according to this previous document, it is not possible to treat the walls of construction which are the seat of high humidity, especially the area which is at ground level, both under the influence of the water contained in the soil which can migrate towards construction, and under the influence of variations in ambient air temperature. Because, according to this previous process, the cathode is positioned below the ground level in which the construction.

The object of the invention is to provide a method for eliminating the humidity of the walls which is simple to implement, inexpensive and effective quickly and steadily over time.

More specifically, the subject of the present invention is a method to combat the humidity of the walls of an implanted construction in terrestrial soil by permanently sealing cracks, consisting of establish an electrical circuit whose negative polarity is applied to the entire construction and whose positive polarity is applied in the soil in which said construction is implanted, characterized in that it further consists in applying the negative polarity above the ground level of way that the electric field produced between the two polarities propagates to the less in the part of the construction which is located at ground level to form a lasting barrier to the rise, by capillary action, of said moisture along the walls of the building.

According to another characteristic of the present invention, it is apply negative polarity at at least one point of said construction in its most conductive massive part.

• la figure 1 est une vue schématique en perspective d'une maison équipée d'un dispositif permettant de mettre en oeuvre le procédé selon l'invention, montrant le positionnement d'une électrode et de la prise de terre par rapport à l'ensemble de la construction et par rapport au sol;
• la figure 2 est une vue schématique partielle en coupe du mur de la maison de la figure 1, montrant le positionnement de l'électrode et de la prise de terre reliées à une source de courant continu;
• la figure 3 est un schéma électrique du dispositif illustré shématiquement sur la figure 1;
• les figures 4a et 4b sont des vues schématiques partielles, respectivement de face et en coupe, d'une variante de réalisation de ce dispositif, montrant le positionnement de l'électrode dans un des joints reliant les éléments constitutifs du mur;
• la figure 5 est une vue schématique en perspective d'une maison comprenant un autre mode de réalisation d'un dispositif permettant de mettre en oeuvre le procédé selon l'invention;
• la figure 6 est une vue schématique partielle en coupe du mur de la maison de la figure 5 comprenant l'électrode, montrant le positionnement de cette électrode face à un mur de refend; et
• la figure 7 est une vue schématique en coupe de la maison de la figure 5, pour illustrer la répartition du champ électrique.

The invention will be better understood with the aid of the description given below by way of illustrative and nonlimiting example as well as of the drawings in which:

• Figure 1 is a schematic perspective view of a house equipped with a device for implementing the method according to the invention, showing the positioning of an electrode and the earth connection with respect to the set of construction and in relation to the ground;
• Figure 2 is a partial schematic sectional view of the wall of the house of Figure 1, showing the positioning of the electrode and the earth connection connected to a DC source;
• Figure 3 is an electrical diagram of the device illustrated schematically in Figure 1;
• Figures 4a and 4b are partial schematic views, respectively from the front and in section, of an alternative embodiment of this device, showing the positioning of the electrode in one of the joints connecting the constituent elements of the wall;
• Figure 5 is a schematic perspective view of a house comprising another embodiment of a device for implementing the method according to the invention;
• Figure 6 is a partial schematic sectional view of the wall of the house of Figure 5 comprising the electrode, showing the positioning of this electrode facing a cross wall; and
• Figure 7 is a schematic sectional view of the house of Figure 5, to illustrate the distribution of the electric field.

The method according to the invention generally consists in subject the entire construction to be treated to the action of a field low intensity electric.

To do this, we use a small number of electrodes distributed in the walls of the building to be treated, as described below in reference to Figures 1 to 4.

By low number of electrodes is meant the implantation of a single electrode, or even two, three or four electrodes when it comes to tall buildings. Generally speaking, we are led to use a number more or less large electrodes according to the permeability of the walls and therefore according to the nature and condition of its constituent elements. Experience has shown that a single electrode is usually enough to, in a way, transform the giant electrode construction. This is the case described below.

FIG. 1 illustrates a device making it possible to implement the process according to the invention applied to a single-family house 5 in size average.

As we can see in this figure, we insert an electrode 10 in an exterior wall 12 of said house 5.

According to the example shown diagrammatically in FIG. 1, the electrode 10 is introduced into an exterior wall on the exterior side of the building but we can completely plan to insert it on the inside and even in a wall interior such as a cross wall, as explained below. In fact, we places the electrode in order to obtain a good distribution of the electric field created on the whole construction.

To set up the electrode 10, a recess 14 (see figure 2) in wall 12 at the chosen location and cover possibly the walls of this recess 14 with a conductive varnish based on graphite powder or any other product which improves the contact.

The electrode 10 consists, for example, of an expansion bolt or other conductive material such as copper.

Reliable result can be achieved with a conductive electrode about ten millimeters driven over two-thirds of the thickness of the wall in using a conductive varnish based on graphite powder as mentioned above.

The electrode 10 is placed at a height h relative to the level of the ground, about three meters.

Furthermore, an earth plug 16 is planted in the ground. Here, taking of earth 16 is advantageously placed at a distance d from the foot of the wall 12, of the order of a few tens of centimeters.

Finally, a direct current source 18 is provided (not represented in FIG. 1) to which the electrode 10 and the earth connection are connected 16, as shown in more detail in FIG. 2.

If we now refer to Figure 2, we can see more precisely that the electrode 10 is connected to the negative pole of the direct current source 18, by an electrical conductor 20 and the earth connection 16 at the positive pole of this source 18, by another electrical conductor 22.

A closed electrical circuit is thus established between the electrode 10, the earth 16, the DC source 18 and the wall 12.

The choice of the type of direct current source 18 is often influenced by both commercial and practical considerations.

It can be, for example, a mains supply with a, or even several, rechargeable battery, as shown in Figure 3.

• les voies V1 et V'1 qui constituent deux voies parallèles selon lesquelles l'électrode 10 est alimentée par une source de courant continu dérivée d'une alimentation sur secteur. Selon la voie V1, l'électrode 10 est directement alimentée par le courant continu basse tension issu du pont redresseur 34, par l'intermédiaire d'une diode 40. Selon la voie V'1, on alimente l'électrode 10 et on charge la batterie 36. Dans ce cas, on prévoit un régulateur de charge 42 et une diode 44.
• la voie V2 selon laquelle l'électrode 10 est alimentée par la batterie 36, par l'intermédiaire de la diode 44.

If we refer to the electrical diagram of Figure 3, we see that the device is powered by a high voltage alternating current source 30. An isolation transformer 32 and a rectifier bridge 34 are provided to obtain a low direct current voltage. In the case considered here, the device comprises a rechargeable battery 36 connected to an earth connection 38. Such a device can therefore operate in the following two ways:

• the channels V1 and V'1 which constitute two parallel channels according to which the electrode 10 is supplied by a direct current source derived from a mains supply. According to the path V1, the electrode 10 is directly supplied by the low-voltage direct current coming from the rectifier bridge 34, via a diode 40. According to the path V'1, the electrode 10 is supplied and charged the battery 36. In this case, a charge regulator 42 and a diode 44 are provided.
• the channel V2 by which the electrode 10 is supplied by the battery 36, via the diode 44.

This device has the advantage of being able to operate on the mains or on battery when there is an involuntary or voluntary power cut for example for dwellings which are not regularly occupied.

In other cases, the direct current source 18 consists, by example, in commercially available 1.5 volt batteries. For a medium-sized detached house, for example, two batteries are enough to autonomy of at least six months.

You can also replace the mains supply with the use of solar photo-cells, in particular for buildings which do not are occupied only occasionally and not regularly. The primary source feed in this case a certain randomness and may be subject to discontinuities, provision is advantageously made for presence of a buffer storage battery.

The intensity of the current is chosen according to the importance of the construction to be treated and the material of the walls. The higher the wall material is compact, e.g. walls made of bricks or stones bound by a rich cement, the more we can apply a weak current. On the contrary, if the walls are made of grinders assembled with a poor mortar, we apply a current higher intensity because the fine capillaries are more numerous than in the first case.

The vertical component of the established electric field is of the order of millivolt per meter at the base of the walls, whatever their nature. It should be noted that this vertical component is significantly less than that of the fields applied by electro-osmosis and / or electrophoresis methods.

In addition, the conductivity of the wall varies with its humidity according to the presence of underground springs, heavy rainfalls, etc., so we have a self-regulation of the current whose intensity increases with a humidity increases and decreases when it also decreases, for a relatively constant field.

It should be noted that, given the specific positioning of the electrode at a height h for example of about three meters, the influence of the electric field created is much more extensive than in the case of previous techniques and this is the set of construction walls that we subject to the action of said electric field.

In addition, the electrode is placed in a part of a wall supposed to be the most conductive.

Figures 4a and 4b illustrate the case where the wall 50 to receive the electrode 48, is made of concrete blocks, bricks, stones 52 or other elements materials connected to each other by a mortar or cement used joints to form the wall. The electrode 48 is then preferably placed in one of the seals 54 connecting the elements 52.

Figures 5 and 6 illustrate, for their part, the case of a construction 60 comprising a cross wall 62. Then an electrode 64 of preferably in the immediate vicinity of this wall 62 or even in the cross wall itself if it has a thickness greater than that of the exterior walls so to place themselves in the most massive part of the construction. Here, electrode 64 is introduced into an exterior wall 66 facing the cross wall 62. This allows to further improve the diffusion and distribution of the electric field.

In Figure 5, we see that the electrode 64 is placed at a height h ' about three meters. In addition, an earth plug 68 is planted in the ground. Advantageously, it is placed at a point distant from an exterior wall of construction. Finally, a direct current source is provided (not shown) of the aforementioned type to form a closed circuit with the wall 62, the electrode 64 and the earth electrode 68 similar to that shown diagrammatically in FIG. 2.

The vertical component of the electric field created is maximum at plumb with the electrode 64 (point A) and decreases as one moves away from it distant.

Point A: 2,5 mV/m

Point B : 1,5 mV/m

Point C : 1,1 mV/m

Point D : 0,7 mV/m

Point E : 1 mV/m

Point F : 0,5 mV/m

Point G : 1,1 mV/m

The values of the vertical component of the electric field created, at the different points indicated in Figure 7, are as follows:

Point A: 2.5 mV / m

Point B: 1.5 mV / m

Point C: 1.1 mV / m

Point D: 0.7 mV / m

Point E: 1 mV / m

Point F: 0.5 mV / m

G-spot: 1.1 mV / m

These measurements were made about twenty centimeters above from ground level and are expressed in millivolt per meter (mV / m).

It is thus observed that the small potential difference which exists at the base of the walls (including the floors in the absence of crawl space), that is to say at the wall / floor interface, is sufficient for reactions occur in this area. We can say that we are transforming into a huge electrode, on the one hand the whole construction, and on the other hand the ground on which the construction is located. Also, the walls play the role of cathode. Everything seems to happen as if we had an in situ electrophoresis of components present in the soil and in particular a displacement of the gases occluded in the soil. The clogging of the cracks in the walls is thus observed very quickly thanks to the gaseous molecules, and a "defusing" of the phenomenon of rising in the walls, of moisture coming from the ground is then obtained.

Claims (2)

1. Process for combating dampness of the walls of a structure implanted in ground which permanently fills the cracks, consisting in the creation of an electric circuit the negative polarity of which is applied to the whole of the structure (5-60) and the positive polarity of which is applied to the ground in which the said structure is implanted (16-68), characterized by the fact that it also consists in applying the negative polarity above ground level in such a way that the electrical field produced between the two polarities is propagated at least in the part of the structure which is situated at ground level to form a permanent barrier to the rising of the said dampness up the walls of the structure by capillarity.
2. Process according to claim 1, characterized by the fact that the negative polarity is applied to at least one point (10-64) of the said structure (5-60) in its most conductive solid part (12-60-66).

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