GB2101188A

GB2101188A - Damp proofing of walls

Info

Publication number: GB2101188A
Application number: GB08212049A
Authority: GB
Inventors: Alicia Bacinska; Andrzej Bacinski
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-04-24
Filing date: 1982-04-26
Publication date: 1983-01-12
Also published as: FI820503L; SE450264B; DE3215340A1; SE8104071L; IT8220936A0; ES8302160A1; IT8219758A0; IT1210877B; FI69497C; NO821366L; DE3215340C2; NO161692B; SE8202570L; PL138249B1; NO161692C; ES510340A0; PL230824A1; DK29882A; FI69497B; GB2101188B

Abstract

Damp proofing of a wall 1 is affected by means of an electro- osmotic installation, which is supplied by a source 7 with an alternating voltage with a positive average value for the period. The voltage is applied to electrodes 4 in the wall 1. A hydrophobic agent such as silicone is supplied to sloping holes 8 in the wall. The dynamic and impulsive action of the alternating voltage increases remarkably the speed of the drying process and the range of penetration of a hydrophobic agent, orders and imparts dynamism to water particles, diminishes the occurrence of electrode corrosion and assures also drying and sealing of pores which are very small and vary in size. <IMAGE>

Description

SPECIFICATION Damp proofing of walls This invention relates to damp proofing of walls, whereby a wall is dried by means of an electro-osmotic installation and holes are arranged by for instance drilling, within the area affected by the electrically generated field and an hydrophobic agent is inserted into said holes.

From Polish Patent Specification No. 103.633 is known a method according to which a drying process of a wall is conducted by means of an electro-osmotic installation for wall moisture content of 1 to 8% range. Furthermore, holes are drilled within the range of electric field activity, preferably at an angle of 350 to the horizontal; to these holes a hydrophobic agent, that is also electrically neutral, is being continually introduced; the poles of this electro-osmotic installation are being changed into the opposite, creating a depression in the capillaries which is a result of an electro-osmotic fluid motion towards the negative pole; the hydrophobic agent being drawn into the inner wall creates a barrier against damp.

When this method has been applied, the initial drying process necessary to achieve the required humidity takes up to a couple of months.

Additionally, the efficiency of the drying process is diminished by the existence of a permanent electric field which with polarizing electrodes, at the same time causes their corrosion. Moreover, these generated electro static forces limit considerably the range of penetration of the hydrophobic agent.

The principal object of the present invention is thus to provide a method of the kind mentioned above which mitigates the problem.

According to the invention, there is provided a method of damp proofing a wall, in which the wall is dried by means of an electro-osmotic installation and holes (8) are arranged within the area affected by an electrically generated field and a water-repelling (hydrophobic) agent is introduced into the holes (8), wherein the electric field is created by applying an alternating voltage with a positive average, the duration of the positive pulse of the waveform of the applied field, during which drying and feeding of the wall (1) with the said agent takes place, is 2 to 20 times longer than the duration of the negative pulse, and the duration of the negative pulse is not less than 20 ms.

Also according to the invention there is provided electro-osmotic apparatus for damp proofing a wall, comprising a row of electrodes in the wall, means for applying a voltage relative to earth, to the electrodes, and means for supplying a damp-proofing agent to a row of holes in the wall, wherein the voltage applying means is constructed to deliver an alternating voltage having a positive average value, the duration of the negative pulses of the voltage being not less than 20 ms and the duration of the positive pulses thereof being 2 to 20 times that of the negative pulses.

The resulting dynamic and impulsive action of the alternating voltage increases remarkably (by a factor of 2) the speed and efficiency of the drying process and at the same time it increases also the range of penetration of the hydrophobic agent.

The method according to the invention makes possible effective drying of pores with very small and varying sections. With this solution also the phenomenon of electric corrosion of the electrodes has been diminished.

The invention will now be further described by way of example with reference to the drawings, in which: Fig. 1 shows diagrammatically a damp proofing installation, and Fig. 2 shows the waveform applied voltage.

The electro-osmotic installation is placed in the building wall 1 between the ground level 2 and the joists 3. A row of electrodes 4 is placed in the wall, and earth electrodes 5 in the form of a flat bar, a flat iron bar or a pipe are buried in the ground. Insulated electric cables 6 supply electrical energy from a source 7 in the form of an alternating voltage with a positive average pulse amplitude to the electrodes 4 and 5. The drying process serves to lower the moisture content of the wall to 10%.

Between the electrode 4 and the ground level 2 water-repelling holes 8 are drilled at an angle of 300 to the horizontal. To these holes 8 a hydrophobic (water-repelling) agent is introduced, such as for instance silicon resin. At the same time the electrodes 4 and 5 are fed with alternating voltage with positive average pulse amplitude for the period, as shown in Figure 2, whereby the period for positive average impulse amounts to 1 second and the negative impulse to 200 ms. The interval between the negative impulse and the following positive impulse is also 200 ms. Owing to the application of alternating voltage for supplying the electrodes, the required drying has been effected within a period of time approximately 5 times shorter depending on the thickness of the wall and its internal dampness.

1. A method of damp proofing a wall, in which the wall is dried by an electric-osmotic installation and holes (8) are arranged within the area affected by an electrically generated field and a waterrepelling (hydrophobic) agent is introduced into the holes (8), wherein the electric field is created by applying an alternating voltage with a positive average, the duration of the positive pulse of the waveform of the applied field, during which drying and feeding of the wall (1) with the said agent takes place, is 2 to 20 times longer than the duration of the negative pulse, and the duration of the negative pulse is not less than 20 ms.

2. A method of damp proofing a wall, substantially as hereinbefore described with reference to the drawings.

3. Eiectro-osmotic apparatus for damp proofing a wall, comprising a row of electrodes in the wall,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Damp proofing of walls This invention relates to damp proofing of walls, whereby a wall is dried by means of an electro-osmotic installation and holes are arranged by for instance drilling, within the area affected by the electrically generated field and an hydrophobic agent is inserted into said holes. From Polish Patent Specification No. 103.633 is known a method according to which a drying process of a wall is conducted by means of an electro-osmotic installation for wall moisture content of 1 to 8% range. Furthermore, holes are drilled within the range of electric field activity, preferably at an angle of 350 to the horizontal; to these holes a hydrophobic agent, that is also electrically neutral, is being continually introduced; the poles of this electro-osmotic installation are being changed into the opposite, creating a depression in the capillaries which is a result of an electro-osmotic fluid motion towards the negative pole; the hydrophobic agent being drawn into the inner wall creates a barrier against damp. When this method has been applied, the initial drying process necessary to achieve the required humidity takes up to a couple of months. Additionally, the efficiency of the drying process is diminished by the existence of a permanent electric field which with polarizing electrodes, at the same time causes their corrosion. Moreover, these generated electro static forces limit considerably the range of penetration of the hydrophobic agent. The principal object of the present invention is thus to provide a method of the kind mentioned above which mitigates the problem. According to the invention, there is provided a method of damp proofing a wall, in which the wall is dried by means of an electro-osmotic installation and holes (8) are arranged within the area affected by an electrically generated field and a water-repelling (hydrophobic) agent is introduced into the holes (8), wherein the electric field is created by applying an alternating voltage with a positive average, the duration of the positive pulse of the waveform of the applied field, during which drying and feeding of the wall (1) with the said agent takes place, is 2 to 20 times longer than the duration of the negative pulse, and the duration of the negative pulse is not less than 20 ms. Also according to the invention there is provided electro-osmotic apparatus for damp proofing a wall, comprising a row of electrodes in the wall, means for applying a voltage relative to earth, to the electrodes, and means for supplying a damp-proofing agent to a row of holes in the wall, wherein the voltage applying means is constructed to deliver an alternating voltage having a positive average value, the duration of the negative pulses of the voltage being not less than 20 ms and the duration of the positive pulses thereof being 2 to 20 times that of the negative pulses. The resulting dynamic and impulsive action of the alternating voltage increases remarkably (by a factor of 2) the speed and efficiency of the drying process and at the same time it increases also the range of penetration of the hydrophobic agent. The method according to the invention makes possible effective drying of pores with very small and varying sections. With this solution also the phenomenon of electric corrosion of the electrodes has been diminished. The invention will now be further described by way of example with reference to the drawings, in which: Fig. 1 shows diagrammatically a damp proofing installation, and Fig. 2 shows the waveform applied voltage. The electro-osmotic installation is placed in the building wall 1 between the ground level 2 and the joists 3. A row of electrodes 4 is placed in the wall, and earth electrodes 5 in the form of a flat bar, a flat iron bar or a pipe are buried in the ground. Insulated electric cables 6 supply electrical energy from a source 7 in the form of an alternating voltage with a positive average pulse amplitude to the electrodes 4 and 5. The drying process serves to lower the moisture content of the wall to 10%. Between the electrode 4 and the ground level 2 water-repelling holes 8 are drilled at an angle of 300 to the horizontal. To these holes 8 a hydrophobic (water-repelling) agent is introduced, such as for instance silicon resin. At the same time the electrodes 4 and 5 are fed with alternating voltage with positive average pulse amplitude for the period, as shown in Figure 2, whereby the period for positive average impulse amounts to 1 second and the negative impulse to 200 ms. The interval between the negative impulse and the following positive impulse is also 200 ms. Owing to the application of alternating voltage for supplying the electrodes, the required drying has been effected within a period of time approximately 5 times shorter depending on the thickness of the wall and its internal dampness. CLAIMS

3. Eiectro-osmotic apparatus for damp proofing a wall, comprising a row of electrodes in the wall, means for applying a voltage, relative to earth, to the electrodes, and means for supplying a dampproofing agent to a row of holes in the wall, wherein the voltage applying means is constructed to deliver an alternating voltage having a positive average value, the duration of the negative pulses of the voltage being not less than 20 ms and the duration of the positive pulses thereof being 2 to 20 times that of the negative pulses.

4. Electro-osmotic damp proofing apparatus substantially as hereinbefore described with reference to the drawings.