WO2006026854A1

WO2006026854A1 - Method for treating wood by internal-external diffusion

Info

Publication number: WO2006026854A1
Application number: PCT/CA2005/001356
Authority: WO
Inventors: Libère Nitunga
Original assignee: Kebeya, Evariste
Priority date: 2004-09-06
Filing date: 2005-09-06
Publication date: 2006-03-16
Also published as: AP2007003965A0; EP1877231A4; EP1877231A1; MA27817A1; CH697453B1

Abstract

The invention relates to a method for preserving wood having a large cross-section that is characterized by an internal-external diffusion of the treating product which slowly migrates toward the periphery over the entire lifespan of the element starting from a reserve placed inside the wood to be treated and which can be renewed as many times as needed.

Description

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Description

The present invention consists in a method for treating solid wood by diffusiorrr ^{"characterized} in particular by the development of a longitudinal reservoir within the stem, wherein one puts a processing product that will impregnate the wood by diffusion 5 internal - external.

Wood treatment by diffusion or double diffusion is well known. However it is an external - internal diffusion. That is, the treatment product is applied to the outer surface of the wood, generally small in size, and diffuses inwardly. Conventional double diffusion treatment consists in using two different treatment products, separately and successively, in order to put them in contact only when they are already inside the wood, insofar as their combination gives rise to compound which is difficult to dissolve in water and which could not have diffused into the wood. Among the drawbacks of external-internal diffusion treatment methods are:

- The difficulty of bringing the entire external surface of the wood into contact with the treatment product in sufficient quantities during the entire treatment period. This is even more complicated when it is a double diffusion, and that the product used is 0 in the form of paste.

- After treatment, the antiseptic product, usually in the form of paste, will be found in excess on the outer surface of the wood; you have to pick it up and clean the wood.

As for the new internal-external diffusion treatment method, it can be noted that:

. After introduction of the treatment product into the inner tank, the trunks are stored in a shed without any particular arrangements, until the diffusion is complete.

This advantage alone is sufficient to compensate for the constraints of the new process, related to the need to arrange the inner tank by drilling, and the need to complete the level of the product in the tank as and when the impregnation.

. At the end of the process, the outer surface of the wood is clean, with no excess of treatment product. The most suitable treatment product for the new process is cooking salt (NaCl), which has antiseptic and antifungal properties. known. Its anti-termite properties have also been confirmed by experiments carried out by the author. Cooking salt acts mainly by dehydration, thanks to its very high osmotic power. See also meat preservation and fish salting. However, cooking salt is very soluble in water, and therefore easily leachable. Thus, for wood likely to come into contact with moisture or the soil, oil or other fat is added, which gives rise to a treatment in two phases: 1 ° Impregnation of wood with cooking salt by diffusion or injection: 2 ° Impregnation of wood with oil or other fat by diffusion. For some dimensions of the wood, it is possible to carry out a simple diffusion using a highly salty oil. The combined use of cooking salt and oil has many advantages:

- Generally, the oil itself has antiseptic properties, which greatly enhances the protection provided to wood;

- The oil increases the resistance of the salt to leaching, which allows the use of treated wood outdoors or in contact with the ground;

- The oil covers the wood assembly fittings with an impermeable layer that protects them against corrosion.

- The presence of cooking salt in the wood greatly facilitates the diffusion of the oil, with favorable consequences on the speed of impregnation, the level of penetration and retention of the treatment product.

- NaCl contributes to the uniformity of moisture inside the wood and the creation of good drying conditions.

However, the internal-external diffusion treatment method on a trunk several meters long assumes the possibility of producing in practice a longitudinal cavity in solid wood having a length greater than that of conventional drill bits and auger, which is of the order of 1 meter.

A technique of drilling an interior cavity in a long trunk is part of the present invention.

This technique consists in using an auger whose body is not perfectly rigid, contrary to the usual situation. For drilling to be possible with such an auger, it must be maintained in the axis by fixed supports. During drilling, bearings allow the auger to rotate freely in the fixed supports. These bearings are easily detachable from their respective fixed supports. In addition, the inner diameter of the bearings is slightly greater than the outer diameter of the auger, so that it can slide unhindered inside said bearings. So in case of rotation of the auger, the bearing allows it to rotate without friction, and in case of translational movement (when the auger enters the trunk), the bearing allows it to advance unhindered.

For this to be possible, the bearing is fixed on a horizontal support. The operator, who holds the drill at the other end of the auger, successively detaches the bearings of the various supports and tilts the latter in a vertical position as the bit penetrates the trunk and the operator advances with the drill.

A conventional auger is lengthened with a hose of adequate length, such as a 1/2 "galvanized pipe such as is commonly used in plumbing.The diameter of the pipe is slightly smaller than that of the auger head to allow a free space for evacuating the sawdust entrained by the water injected into the pipe from the other end of the latter, with the aid of a device making it possible to seal between the rotating pipe and the fixed water supply under a certain pressure.

At the end of the drilling process, all bearings will remain on the pipe between the drill and the base of the trunk, and all vertical supports will have been tilted to the vertical position to let the operator, one by one.

For the wood that is in contact with the ground but sheltered from the weather, for example the columns of buildings, the inner cavity can be limited to the part of the buried column. But the part not exposed to moisture must have been treated "once and for all" with cooking salt, borates or any other effective product. To greatly reduce the charging intervals of the inner tank, it is necessary to slow down as much as possible the migration of the treatment product to the periphery, while ensuring that the latter retains a sufficient dose to discourage termites and prevent the development of rot fungi. It is for example to interpose a semi-permeable device between the product stock and the inner surface of the pole, to add fats which have in addition a repellent effect, etc.

It is in anticipation of such eventualities that the stock of product is renewable, otherwise the protection of the buried part of a post not exposed to bad weather would be for life, as the part above ground.

Patent document FR 808588 discloses a method of treatment by displacement of sap, a hollowed out pole inside, in order to overcome the inequality of the distribution of the treatment product in the radial direction. To do this, the method aims to inject the treatment product radially from the outside to the inside and vice versa, and axially from the base to the top and vice versa. However, neither the objective pursued nor the principles used nor the expected results have nothing to do with the present invention.

The same is true of the document RU 2095237, where it is a matter of making a recess inside a wooden post, in order to facilitate penetration, by simultaneous internal and external impregnation. Antiseptic treatment is performed externally and internally of log. A diffusion of the antiseptic on both sides necessarily gives better results than a diffusion on only one face of them, all things being equal. The merit of the invention is therefore essentially to halve the path to be covered by the treatment product. JP 8053901 also relates to a technique for preserving a wooden beam, which consists in producing an internal cavity for filling it with activated carbon. Apparently the activated carbon, which is the treatment product used, is simply "housed" inside a wood of modest dimensions, since the interior can be hollowed out by conventional means. Figure 1 shows a wooden post used in the construction of a building, so with a part in contact with the ground and a part without contact with the ground and not subjected to bad weather.

Figure 2 shows a power line pole or telephone, or a pole used in the construction of a fence. Figure 3 shows the concentration gradient of the treatment product, from the inner reserve to the periphery.

Figure 4 shows a lengthening system of a wood wick, which allows to hollow out the central part of the pole of any length.

In Figures 1 and 2, there are: the wood to be treated (1), the refillable reservoir (2), control and filling ports (3), an impermeable layer (4), the soil (5) and a asphalt hat (6).

In Figure 3, there are: the wood to be treated (1), the refillable tank (2), the outer surface of the post (7), and the pace of the density of the treatment product (8).

Claims

1. A technique of wood treatment by diffusion, characterized by a routing of the treatment product from the inside to the periphery from a longitudinal tank arranged inside, tank which can be replenished with treatment product on wood in service, if needed.

2. A technique of treating wood with cooking salt, characterized by the strengthening of its antiseptic performance and its resistance to leaching by impregnation with oil or other fats.

3. A dual diffusion wood treatment technique, characterized by the successive or simultaneous use of several chemicals, the first to be introduced is cooking salt or any other product having a high diffusion capacity, a product which has the the role of attracting other products introduced later or simultaneously, and thus increase their diffusion capacity in wood.

4. A technique for creating a longitudinal cavity within a long wood trunk, characterized by the use of an elongated auger using a pipe whose length is equal to that or at half the size of the trunk to be drilled, and the diameter of which is slightly smaller than that of the auger, to create a space through which the sawdust is driven outside by water injected into the pipe during drilling said pipe being held by a plurality of fixed supports, which are retracted as the operator progresses during drilling, which is made possible by the use in the fixed supports, of bearings which can slide along of the pipe and which remain permanently on the latter.

5. A wood drying technique, characterized by impregnating the freshly cut wood with all its salt to the kitchen salt by any appropriate means, in order to accelerate the drying process and to standardize the humidity in the different zones wood.