EP0899389A1 - Method and apparatus for drying walls - Google Patents

Abstract

The supply to the electrodes is chopped with timed intervals between pulses, maximizing the effect of the applied electrical energy. The electrical system for drying out walls includes at least one cathode and anode (1,1') connected to the output terminals of an active electronic circuit (2). This circuit delivers polarized pulses to the electrodes, at spaced time intervals. The power and duration of the pulses is sufficient to impose their polarity on the water molecules and suspended particles held within the portion of wall between the electrodes. The circuit includes an overload protection module (8), a stabilizing module (5), and a voltage chopping circuit (6) linked to an adjustable RC timing circuit (7). The output is protected by a further circuit (9).

Description

The present invention relates to the building sector, more particularly the treatment of walls, in particular foundations, buildings undergoing infiltration or upwelling, and relates to a process for drying walls and an apparatus for its implementation.

The phenomena of electro-osmosis, electrophoresis and have been well known and treated for a very long time in the technical literature.

These aforementioned physical phenomena have repeatedly served as a basis for the realization and development of many processes, devices, and devices, active and passive, in an attempt to eliminate the causes and related effects infiltration and, more particularly, upwelling in the walls of buildings.

However, the solutions developed so far show either of a complex constitution and therefore of a high cost price, or of an efficiency reduced and / or time-limited processing or consumption of significant energy and therefore high operating costs, if not several of the aforementioned drawbacks.

The main object of the invention is therefore to design a process and an efficient wall drying device with a low operating cost high, in particular with a maximum operating cost / efficiency ratio.

Another object of the invention is to design an aforementioned device of which the structure is simple, which is easily achievable in a standardized manner large quantity and low cost and whose implementation is safe for the user whatever his qualification.

Another object of the invention is to design an apparatus mentioned above, the corrosion resistance and the service life of which are notably increased compared to existing devices.

To this end, the subject of the present invention is a method dewatering of walls, in particular of foundation walls, by means of electrodes installed in the wall to be dried, comprising at least one cathode and at least an anode and connected to the output terminals of an active electronic device. characterized in that it consists in delivering polarized electrical pulses, spaced in time, to said electrodes whose power and duration are sufficient to impose their polarity on water molecules and granules in suspension present in the portion of wall located between said at least one cathode and said at least one anode.

The invention also relates to an apparatus for setting work of the aforementioned treatment method and comprising at least two electrodes intended to be installed in the wall to be treated and connected to a device active electronics powered by the mains, apparatus characterized in that said device mainly consists of a module delivering pulses electric polarizers, associated with protection circuits forming input interface connected to the mains and output interface connected to the electrodes.

• la figure I est une représentation en blocs synoptiques de l'appareil selon l'invention ;
• la figure 2 est une vue en élévation latérale et en coupe d'un mur, montrant l'installation des électrodes faisant partie de l'appareil représenté sur la figure 1 ;
• la figure 3 est une vue selon la direction F du mur représenté sur la figure 2 ;
• les figures 4 et 5 sont des représentations temporelles de signaux impulsionnels de polarités opposées délivrés par l'appareil et appliqués aux électrodes implantées dans le mur à traiter ;
• la figure 6 est une représentation schématique d'une installation permettant un test comparatif de l'appareil selon l'invention avec une source de tension continue, et,
• les figures 7 et 8 représentent des courbes comparatives recueillies au moyen de l'installation de la figure 6, pour des briques en teiTe cuite à trous (figure 7) et des briques en béton cellulaire (figure 8).

The invention will be better understood from the description below, which relates to a preferred embodiment, given by way of nonlimiting example, and explained with reference to the appended schematic drawings, in which:

• Figure I is a block diagram representation of the apparatus according to the invention;
• Figure 2 is a side elevational view in section of a wall, showing the installation of the electrodes forming part of the apparatus shown in Figure 1;
• Figure 3 is a view in the direction F of the wall shown in Figure 2;
• Figures 4 and 5 are temporal representations of impulse signals of opposite polarities delivered by the device and applied to the electrodes implanted in the wall to be treated;
• FIG. 6 is a schematic representation of an installation allowing a comparative test of the apparatus according to the invention with a DC voltage source, and,
• FIGS. 7 and 8 represent comparative curves collected by means of the installation of FIG. 6, for bricks in baked teiTe (FIG. 7) and bricks in aerated concrete (FIG. 8).

As shown in the figures of the accompanying drawings, the process for dewatering walls, in particular foundation walls, is implemented at means of electrodes 1, 1 ′ implanted in the wall 3 to be dried, comprising at least at least one cathode 1 and at least one anode 1 ', and connected to the output terminals of a active electronic device 2.

According to the invention, the dewatering process consists of deliver polarized electrical pulses, spaced in time. to said electrodes 1, 1 ', whose power and duration are sufficient to impose their polarity to water molecules and suspended granules present in the portion 3 'of wall 3 located between said at least one cathode 1 and said at least a 1 'anode.

Thus, the pulse signals applied to the electrodes 1, 1 ' have sufficient power to stop the upward movements of the water molecules in wall 3 under the action of the potential difference present naturally in said wall, while allowing the device to be stressed only discontinuously, during the short periods of application of the pulses (marked with I in FIGS. 4 and 5), and to be placed in a state of rest (marked by 2 in Figures 4 and 5) between the aforementioned active periods or working time.

This not only results in substantial energy savings, but also an increased lifespan of the device used.

Depending on the state and humidity conditions of the wall 3 to be treated, the amplitude of the pulse voltage can advantageously be between 12 V and 3 () V, said pulses being delivered with an intensity which can reach 3 A and being spaced a few milliseconds to a few tens seconds.

According to a preferred embodiment of the invention, said dewatering process includes several consecutive preprogrammed phases or manually adjustable, each corresponding to a specific state of the wall 3 to process and adapt the parameters of the pulses delivered to the electrodes 1, 1 'and of their repetition, in particular as regards the duty cycle of pulses delivered.

The duty cycle of the applied pulses may. for example. be between 0.2 and 3, preferably between 0.3 and 2.

The determination of the treatment conditions according to the state of the wall 3 may be carried out by qualified persons. who will proceed also after the installation of the device for the implementation of the method according to the invention and its calibration.

In order to be able to process walls 3 whatever the nature of the porous material constituting them and its chemical composition (which determines the sign and magnitude of the electrical charges of the granules dissolved in the medium liquid present in said walls 3 to be treated), the method advantageously provides to deliver to the electrodes 1. 1 'pulses whose polarity is opposite to that of the potential difference naturally existing between the opposite ends of the portion 3 'of wall 3 to be treated.

Thus, by way of illustrative examples, FIG. 4 shows a signal comprising pulses with positive polarity (of the same type as that applied to the electrodes shown in Figure 2), while Figure 5 shows a signal comprising pulses of negative polarity.

The present invention also relates to an apparatus for the implementation of the treatment method described above and comprising at at least two electrodes 1, 1 'intended to be installed in the wall 3 to be treated and connected to an active electronic device 2 powered by sector 10.

In accordance with the invention, and as shown more particularly Figure 1 of the accompanying drawings. said device 2 is mainly constituted by a module 4, 5, 6, 7 delivering pulses electric polarizers, associated with protection circuits 8 and 9 forming input interface connected to sector 10 and output interface respectively at electrodes 1, 1 '.

According to a characteristic of the invention. also represented at Figure I of the accompanying drawings, the aforementioned module is composed of several units or electronic stages 4, 5, 6, 7 connected in series and successively comprising a circuit 4 AC voltage rectifier from sector 10, a cell 5 of voltage stabilization, a circuit 6 voltage chopper and a circuit 7 of time delay.

In order to minimize the generation of interference electromagnetic harmful to the environment (especially for devices in the immediate vicinity), to lead to a space-saving structure possible and to facilitate mass production at a minimal cost, it is advantageously provided that the electronic device 4, 5, 6, 7, 8, 9 is devoid of any inductive circuit, its circuits and electronic units components being exclusively composed of active and passive semiconductor components, preferably made, as much as possible, in the form of integrated circuits.

According to a characteristic of the invention, the rectifier circuit 4 incorporates a filtering and smoothing cell delivering free DC voltage of alternative or variable components.

In addition, the output protection circuit 9 includes a filtering removing the pulse signal components that can generate transients likely to disturb the electromagnetic environment. Of even, the input protection circuit 8 may also be provided with a filter cell.

Said input protection circuit 8, intended to ensure a protection against accidental overload, may consist of a circuit breaker differential or a calibrated fuse for example, while the protection circuit at output 9, intended to provide protection against overloads or short-circuits accidental, preferably consists of a calibrated fuse.

The stabilization cell 5 supplies a constant voltage at its output. independent, within predetermined limits, of the current density delivered at electrodes 1, 1 '.

It is indeed necessary to be able in certain cases to have a high intensity. under constant voltage, this to prevent possible deposits of electrophoresis products of reduced length under high humidity, between two electrodes 1, 1 'opposite, equivalent to the establishment of a low resistance ohmic value between said electrodes and requiring a high current intensity output.

The 6 voltage chopper circuit ensures voltage cutting continuous supplied by cell 5 in power pulses of polarities positive or negative.

The adjustable delay circuit 7 enables. through adjusting R-C constants, setting duration and ratio values cyclic power pulses supplied to electrodes 1 and 1 '.

All the circuits and electronic cells mentioned previously are perfectly known as such to those skilled in the art and therefore do not require additional explanations specifying their constitution and how they work.

To combat and stop the action of corrosion electrochemical. associated with chemical corrosion resulting from the reaction heterogeneous between solid and liquid and attacking the electrodes causing a loss of material of the latter and an alteration of their characteristics electric (conduction), it can be provided according to the invention to implement one or more mechanical and / or electronic protection means, these two protections that can be combined to achieve optimal protective action and maximized.

Thus, according to a characteristic of the invention, the electrodes 1, 1 ' can be covered or surrounded by a mixture of copolymer resin butadiene-styrene (65% to 90% by weight) and carbon powder (10% to 35% by weight), ensuring mechanical protection of the latter.

The electrodes, which may be of any kind, are preferably surrounded by a phoresis product composed of resin of the Pliolite type (registered name) from 70 % to 85%, preferably 80%, by weight and carbon powder of 15%. to 30%, preferably 20%, by weight. This mixture has been shown to be very effective in protecting the electrodes during the application of high positive voltages for several months and has the double characteristic of hardening over time and of increasing its electrical conductivity by polymerizing.

The Pliolite type resin may, for example, consist of a cement graphite glue known under the designation C34 by the company Analab (Hoerdt - France).

Different electrodes (metal and carbon) were tested for 45 days by the inventors with this product and did not show signs of degradation of both the electrodes and the phoresis product. Without this product of protection, the electrodes degraded relatively quickly after a few days, for the less resistant.

According to another characteristic of the invention, the pulses electric polarizers. square, can be modulated by a signal alternating high frequency and low amplitude compared to the frequency and the amplitude of said polarizing pulses, thus ensuring protection electrical of said electrodes.

This electronic protection may consist, more specifically, in modulate square signals with a sinusoidal alternating signal of frequency approximately 800 to 1200 Hz, preferably around 1000 Hz, and of amplitude 1 to 3 V, preferably around 1.5 V, small but sufficient amplitude. This signal positive and negative approximately every 1 / 1000th of a second, creates an electric field which prevents the formation of a corrosive gaseous environment around the electrodes when placed in the material to be protected.

These mechanical and electronic protections for electrodes allow these to be of any kind and therefore to be performed at low cost (metal: steel, iron, copper, aluminum or carbon). The longevity of the electrodes is finds significantly increased.

According to an alternative embodiment of the invention, the electrodes 1 and 1 ' consist of graphite and are installed in wall 3 to be treated according to two substantially parallel and horizontal rows delimiting the wall portion 3 'to to be treated, the electrodes I and 1 ′ of each row being connected together by grooves 11 filled with a conductive mixture of graphite and a binder or a quick setting material such as plaster or mortar.

This arrangement makes it possible to form a cathode 1 and an anode 1 ' continuous extending over the entire length of the row of implanted electrodes 1 or 1 'corresponding and making the related effects more uniform and homogeneous the polarity reversal induced by the power pulses applied to the electrodes I and 1 'installed in the wall 3.

In practice, the electrodes 1, 1 ′ may be introduced into the wall 3 to a depth of about 8 to 25 cm depending on the thickness of said wall and the rows of cathodes 1 and anodes 1 'can be mutually separated from a distance between 25 cm and 1 m, preferably between 25 cm and 5 () cm, depending on the condition of the wall 3 to be treated.

In order to illustrate the effectiveness of the process and the apparatus according to the invention, the inventors carried out comparative tests on bricks red terracotta (use of graphite electrodes) and on bricks aerated concrete (use of stainless steel electrodes - registered name).

For each of these experiments, two bricks, previously fully soaked in water for 24 hours before being tested (therefore identically wet), were each placed in a tank containing water whose level was kept constant throughout the duration of the observation. This level was located just below the cathode line. The two bricks were then subjected, one (control) to a DC voltage of 3 () V, the other (under test) to a pulse voltage of 30V, delivered by the device according to the invention, grooves 12 filled with phoresis product extending on either side of said electrodes 1, 1 '.

The pulse signals delivered by the device according to the invention were shaped so that the duration of each pulse was approximately equal to (). 7 seconds and that the intervals between pulses (rest) were approximately 0.3 seconds.

The strong and rapid decrease in intensity observed on the bricks "under test" by the device delivering a pulse voltage, shows a appreciable reduction of humidity and consequently an accelerated drying of materials.

• brique "sous test" : y = - 3,121 log(x) + 14,491
• brique témoin : y = - 5,090 log(x) + 17,142

The curves of figure 8 can be approached by the following equations:

• brick "under test": y = - 3.121 log (x) + 14.491
• witness brick: y = - 5.090 log (x) + 17.142

Of course, the invention is not limited to the embodiments described and shown in the accompanying drawings. Modifications are still possible. in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims (11)

Method for drying walls, in particular foundation walls, by means of electrodes implanted in the wall to be dried, comprising at least a cathode and at least one anode and connected to the output terminals of a device active electronics, characterized in that it consists in delivering pulses electric polarized, spaced over time, to said electrodes (1, 1 '), the power and duration are sufficient to impose their polarity on molecules of water and suspended granules present in the portion (3 ') of wall (3) located between said at least one cathode (1) and said at least one anode (1 '). Treatment method according to claim 1, characterized in that that, depending on the state and humidity conditions of the wall (3) to be treated, the amplitude of the pulse voltage is between 12 V and 3 () V, said pulses being delivered with an intensity of up to 3 A and being spaced a few milliseconds to a few tens of seconds. Treatment method according to any one of claims 1 and 2, characterized in that it comprises several consecutive phases preprogrammed or manually adjustable, each corresponding to a state determined of the wall (3) to be treated and to a suitable configuration of the pulses delivered to the electrodes (1, 1 ') and their repetition. Treatment method according to any one of claims I to 3, characterized in that it consists in delivering pulses to the electrodes (1, 1 ') whose polarity is opposite to that of the existing potential difference naturally between the ends of the portion (3 ') of wall (3) to be treated. Apparatus for implementing the treatment method according to any one of claims 1 to 4 and comprising at least two electrodes intended to be installed in the wall to be treated and connected to a device active electronics powered by the mains, apparatus characterized in that said device (2) is mainly constituted by a module (4, 5, 6, 7) delivering electric polarizing pulses, associated with protection circuits (X and 9) forming respectively input interface connected to the sector (10) and interface of output connected to the electrodes (1, 1 '). Apparatus according to claim 5, characterized in that the module is made up of several electronic units or stages (4, 5, 6, 7) connected in series and successively comprising an AC voltage rectifier circuit (4) from sector (10), a voltage stabilization cell (5), a chopping circuit (6) voltage and a timing circuit (7) setting the values of the duration of the impulses and their duty cycle. Apparatus according to any one of claims 5 and 6, characterized in that the electronic device (4, 5, 6, 7, 8, 9) is devoid of any inductive circuit, its constituent electronic circuits and units being exclusively composed of active and passive semiconductor components. Apparatus according to any of claims 6 and 7. characterized in that the rectifier circuit (4) incorporates a filtering and smoothing delivering a DC voltage free of alternative components or variable and in that the output protection circuit (9) comprises a filtering removing the pulse signal components that can generate transients likely to disturb the electromagnetic environment. Apparatus according to any one of claims 5 to 8, characterized in that the electrodes (1 and 1 ') consist of graphite and are located in the wall (3) to be treated in two substantially parallel rows and horizontal. the electrodes (1 and 1 ') of each row being interconnected by grooves (11) filled with a mixture of graphite and a binder or a material quick setting such as plaster or mortar. Apparatus according to any one of claims 5 to 9, characterized in that the electrodes (1 and 1 ') are covered or surrounded by a mixture of butadiene-styrene copolymer resin and carbon powder. Apparatus according to any one of claims 5 to 9, characterized in that the polarizing electric pulses, of square shape, are modulated by an alternating signal of high frequency and low amplitude by with respect to the frequency and the amplitude of said polarizing pulses.

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