A CONTACT FREE PROCEDURE FOR ION AND MOISTURE TRANSPORT IN POROUS MATERIALS PLUS APPARATUS FOR ACCOMPLISHING THE PROCEDURE

A contact free procedure for ion and moisture transport in porous materials plus apparatus for accomplishing the procedure.

The invention relates to a procedure of transport of ions and moisture in porous materials e.g. as a method for reducing the contents of salts by transport of salts in these materials.

Known methods

The methods known at present for the treatment of ions and moisture in porous materials, for instance stone, sand etc are:

• A. Electrophysical methods
  
  

  The known procedures are based on the utilization of electical fields and require direct contact with the material. (1)

• B. Electrophysical procedures in connection with sucking material on the surface of the treated material. (2)
• C. Watering methods
  
  

  The material must be dismounted first and hereafter immersed in liquid. (1)

• D. Thermal methods
  
  

  Here the material is heated by el. cables or warm water pipes, which are installed on the material. (1)

• E. High frequency methods
  
  

  Here the material is treated with electric fields of high frequency. The highfrequent electric fields are sent out through an antenna, which is installed in the material. (1)

Methods B,C,D and E also require direct contact with the material as method A.

• (1) Technical periodical:
  
  

  Bautenschutz und Bausanierung 16 (1993), "Trockenlegungs- und
  
  

  Salzbekaempfungsmassnahmen an Mauerwerk", C.Arendt,Dr.Ing.

• (2) Patent:
  
  

  Deutsches Patentamt, Auslegungsschrift 2306814, 12.2.1974, "Verfahren und Vorrichtung zur Entfernung eines Salzausschlages von rohen und gemalten Oberflaechen"

The invention relates to a procedure of transport of ions and moisture in porous materials using a moving magnetic field which penetrates these materials. The procedure is characterized in that the moving magnetic field is produced outside one side of the porous material to be treated using a coil system embedded in a magnetic material, penetrates completely through the material to be treated and is returned back through the material via a magnetic material placed on the opposite side of the material and directed by a moving magnetic field production apparatus using a multiphase coil system.

This application is neither known nor obvious in view of the known techniques.

The application at a moving magnetic field in order to transport ions on or in a wall is neither described in nor indicated in the state of the art.

The electrophysical procedures known at present for transport of ions and moisture in porous materials are all based on the utilization of electrical field effects. Therefore, electrodes have to be installed directly on, or in these porous materials.

The structure of the material, which is to be treated, is therefore very often changed or is in danger to be permanently damaged through the electric field method. The system electrodes used in these procedures are also exposed to corrosion attacks.

General background in connection with a contact free procedure for transport of ions and moisture in porous materials, plus apparatus for accomplishing the procedure.

Using the moving magnetic field procedure together with the corresponding equipment described, there is no need for any mechanical action on, nor any direct contact with the material being treated. The porous material, being treated, is in no way chemically attacked. The treatment can be applied extremely slowly and carefully. The method operates without direct contact also in inaccessible locations. The method is especially in connection with frequency convertors carried out very efficiently. In connection with frequency converters and integrated measuring coils on the passive side, this method can also be used to determine the magnetic material constant of the porous material.

Differences in comparison to systems already existing and the system discription.

The present procedure of transport of ions and treatment of moisture in porous materials utilizes a moving magnetic field, and is different from the other known methods indicated. Hence, the previously indicated advantages are achieved.

The moving magnetic field according to the invention is produced by an apparatus containing a multi phase coil system. Using an installation to return the moving magnetic field, it is possible to lead back the moving magnetic field on the other side of the material with small losses and thus the moving magnetic field is forced through the material. The multiphase coil system, which is necessary to produce the moving magnetic field, is preferably placed in a magnetical material by which a magnetic field concentration and amplification is achieved.

A magnetical return path, necessary for the magnetic field to return with a minimum of losses and to penetrate the porous material completely, can be made using magnetical material without windings, which is preferably assembled in such a manner, that hot spots due to eddy currents are avoided.

When the moving magnetic field passes through a porous material, all the magnetically non neutral parts in the porous material are affected by the field. The parts initially will move in the field's moving direction.

Because of additional accompanying processes, e.g. eddy currents in the porous material, an additional direction of movement of these mobile parts perpendicular to the field moving direction is obtained. It is possible in the porous material to either achieve or amplify this moving effect on these electrically not neutral particles in both perpendicular directions, by the use of two multiphase coil systems, which are embedded in magnetic materials and which are placed antiparallel and phase shifted against each other - which means, a north pole can see a south pole (Fig.4)- having the porous material therebetween.

An apparatus according to the invention for producing movement of ions and moisture in porous materials, comprising means for producing a magnetic field, which completely penetrates these materials, is characterized in that it contains a multiphase coil system embedded in a magnetic material for the production of a moving magnetic field outside one side of the porous material and a passive magnetic material positioned on the opposite side of the porous material for returning the magnetic field, which completely penetrates the porous materials. Because of the very often low magnetic material constants of the porous materials, it is given that the out and return path of the moving magnetic field in accordance with the invention consists of material having high magnetic material constants as opposed to the penetration way.

This apparatus according to the invention producing a moving magnetic field, contains preferably a multiphase coil system, which consists of, in relation to each other, shifted phases. This multiphase coil system is embedded in a magnetic material. The windings can e.g. be placed in a slotted, ferromagnetic, laminated core, wherein the laminations are insulated from each other.

In a preferred embodiment of the invention the total penetration of the porous material is achieved using a field return path having negligible losses. This magnetic return path, having low losses, may for instance be formed by a ferromagnetic core, where the single core plates are insulated from each other.

The core may have slots, which however is not mandatory.

In another preferred embodiment of the invention, the apparatus contains two multiphase coil systems, embedded in magnetic materials, which are phase shifted and antipolar to each other.

Provided that the porous material to be treated, is positioned between two active systems , for instance two ferromagnetic slotted cores having embedded identical coil systems, and if the coil systems are antipolar and the cores displaced to each other, it is rendered possible to either initiate or amplify an ion or moisture movement in both perpendicular directions to the field moving direction.

In another embodiment of the invention resistors or coils or transformers are connected between the supply network and the multiphase coil system. This enables an alternation of the moving magnetic fields amplitude.

In the apparatus according to the invention can be connected a frequency converter in between the supply network and the multiphase coil system. Especially in connection with restoration work it is advantageous to use a gentle treatment of the materials. With respect to the internal loss reduction (heating), it is highly desirable to be able to control or regulate the supply voltage and frequency of the field coils. This can for instance be achieved with the help of a frequency convertor, connected in between grid and the multiphase coil system. The invention is described more in detail with reference to the drawings Fig.1 to Fig.4.

• Fig.1 shows schematicly an apparatus according to the invention for producing a moving magnetic field in the lower part of the drawing. A part of a coil of the multiphase coil system is indicated in a slotted core (shown in cross section). The moving magnetic field is indicated by the arrowed line. The moving magnetic field penetrates the porous material (the white section shown above the coil containing core) and is returned with minimum losses via the unslotted core in the upper part of the drawing. The moving magnetic field is penetrating the porous material once more on its way back to the slotted core.
• Fig.2 shows an apparatus according to the invention connected to a frequency converter in between the supplying network and a three phase coil system. The coil system is embedded in a slotted core. The slotted core is shown on the right hand side of a wall. The core on the left hand side of the wall is working as the low loss return path for the moving magnetic field.
• Fig.3 indicates symbolised with two field lines the magnetic field's passage through a wall, outgoing from the slotted core mounted on the right hand side of the wall. With a suitable phase sequence the magnetic field moves downwards from the top removing the moisture from this wall area. The unslotted core is the moving magnetic field's low loss return path.
• Fig.4 shows some porous material, in this case a church arch, positioned between two slotted cores containing identical coil systems. The cores coil systems are antipolar to each other (symbolised with N=northpole and S=southpole).

The invention will be described more in detail through an example:

In Fig.4 a practical example of working the invention is shown. Some frescos on a salt contaminated plaster layer on the inner side of an arch are endangered due to the crystallization of salt. Using two frequency converter controlled, active systems, which are phase shifted to each other and of opposite polarity but with the moving magnetic field travelling in the same direction, the mobile salts underneath the frescos are transported to the upper surface of the arch. The apparatus according to the invention can always be designed to fit the shape of the material being treated and according to the requirements. It is possible, for each application, to determine the optimal supply voltage, frequency, number of windings etc. of the multiphase coil system.

In a laboratory experiment a two pole, three phase, shellack insulated low voltage winding with a wire diameter of 1 mm was used. Each coil had 120 windings. Nine slots were available for the windings and the number of slots per pole and phase was therefore 1.5. Phase voltage was 16.7 V, the measured current was 4 A, the active component of the current was 2.6 A. The active power was 130W.