DE1000592B - Method and device for deep impregnation of wood by means of high frequency and liquid impregnation agents - Google Patents

Description

The invention relates to a method and a device for soaking wood with oil or the like Application of heat generated by high frequency.

It has been shown in a number of experiments that wood lying in an oil bath, especially hardwood, can be soaked in a short time with oil to 100% saturation by heating in a high-frequency electrical field and subsequent cooling. The soaking time can be shortened if heating and cooling alternate several times (pulsating operation). It was found that a sample of 45 X 65 X 18 mm in an oil bath of 200 ⁰ after 10 minutes still floated on the oil surface and weighed a total of 28 g, while one with ultrashort waves of 12.5 cm in length in the same time pulsating operation-treated sample had perished and weighed a total of 46 g.

It is known per se, not or poorly conductive body, z. B. wood or cellulosic materials, molded materials and the like. To expose a high-frequency electric field in order to produce a certain Purpose, e.g. B. for drying or killing pests, required heat at the same time and to be produced evenly in all parts of the object or good. There is also a method for Preservation of built-in wooden parts is known, in which the pest-infested zones initially through Heated by exposure to high-frequency currents and then treated with the impregnation solution. In this way, the impregnating agent can penetrate deeper into the outer layers of the wooden parts than with pure diffusion or osmosis, but it has not yet been recognized that in dielectric heating a very advantageous option because it saves power and time for soaking, impregnating and the like of wood or wooden objects to saturation. For this it is necessary that the impregnating agent enter immediately after the end of the exposure to heat and air cannot penetrate the pores again, as is the case with the usual impregnation of Wood is the case in the soaking bath. The soaking bath with the wood now provides a layered dielectric and in the high-frequency field, the dielectric losses in the wood initially arise in the interior the wood has a higher temperature than in the outer zones. The rapid rise in temperature in the wood causes a sharp rise in pressure caused by the formation of wood gas, water vapor, etc. will. Most of the gases or vapors escape in the direction of the fibers to the outside, which can be seen through severe blistering on the end faces of the method and apparatus

for deep impregnation of wood

by means of high frequency and liquid

Impregnating agents

Applicant: Deutsche Elektronik G.m.b.H.,

Berlin and Darmstadt,
Darmstadt, Landgraf-Philipps-Anlage 6

Paul Müller, Darmstadt,
has been named as the inventor

Wood in the bathroom. After a while, a state of equilibrium is established. In this In this state, no further heat may then be developed, because the strong wood gas development that ensues would destroy the wood, it charred from the inside out.

After switching off the high-frequency field, the wood that is still in the bath produces by cooling, a negative pressure, which causes the heated thin fluid oil or other impregnating agent pushed into the wood core by the normal air pressure on the surface of the bath will.

Strangely enough, it has been found that the frequency of the high frequency field to which the wood is exposed Heating is subjected to must be very high in order to achieve economical treatment times with economical To achieve power consumption.

The invention makes of this experience for the purpose of soaking wood with oil or other impregnating agents use, such that the wood surrounded by the impregnating liquid, if necessary together with this a high-frequency field with a wavelength in the centimeter-wave range for the purpose of heating, preferably less than 15 cm, exposed and after the high frequency effect has ceased let the wood cool down within the impregnation liquid. Heating and cooling are advantageous of the wood several times, if necessary several times carried out zone by zone.

There are several known possibilities for generating the high-frequency field. Once can

the device for impregnation be designed so that the impregnation material in its impregnation bath between the. Electrodes of a capacitor field is arranged or passed through. However, difficulties can arise here occur because the electrode dimensions come in the size of the wavelength of the field, such as this is known from the gluing of wood in the long-wave capacitor field. On the other hand, it can Wood arranged in the soaking bath in the area of at least one coil field electrode or on this or these are guided along or pass through the inside of the coil. Finally can too an electromagnetic radiation field can be applied, which is generated by means known per se, such as concave mirrors, Horn antenna or the like. Is formed. The radiation field can be in a hollow body conductive material (cavity resonator) can be generated, except for openings for insertion and removal or passing through the material to be treated and for supplying the electrical energy closed on all sides is. The electromagnetic radiator can also consist of at least one turn of an electrical There are conductors through which the material to be treated passes.

The drawing shows an exemplary embodiment of the invention in a schematic representation in section a device for soaking wood in oil. The tub 2 with the soaking liquid stands on the base 1 3; it is closed with a cover that carries the ventilation nozzle 4. Below the liquid level 5, i.e. within the impregnating agent, is the impregnated material 6, ζ. B. a wooden beam between the thorns 7 and 8 is held. The holder is designed so that the wood by means of a Device 9 can be rotated about its longitudinal axis in the impregnation liquid during the impregnation process can,

A waveguide arrangement 10 protrudes from above through a cutout in the cover, that of ultrashort wave generators 11 is fed and generates a high-frequency radiation field in the tub space. The considerable high-frequency energy is applied by two generators 11, e.g. Magnetron tubes can work. To a mutual influence of preferably on the same To prevent frequency working generators., The radiator arrangement 10 consists of two separate Waveguides 12 and 13 which abut against one another on a wall and are excited by a dipole 14 each.

With the arrangement described, a wooden beam measuring 10 × 10 × 70 cm was soaked completely with oil in pulsed operation with three irradiations of 3 minutes each. The weight of the wood from initially 2.5 kg has increased to 5.5 kg at the end of the treatment. The power of the high-frequency system was 5 kW. It is useful to allow the oil bath at the end of the treatment to about 30 to cool ^{the 0th}

The item to be treated can be irradiated in one piece or in zones. It can be a movable radiator are guided several times over the length, so that in this way a pulsating Heating occurs, or the material can flow under several radiators, which are at a distance stand, be led through. It is advantageous to turn the material to be soaked several times in the bath.

Of course, other substances, such as fat, paraffin, etc., can also be used as impregnating agents. With the method described, it is particularly possible to use a suitable varnish on hardwood or glue to solidify and thereby a, new, very resistant building material for diverse Applications.

Claims (5)

PATENT CLAIMS: 1. Process for deep impregnation of wood by heating it with high frequency and treating with known liquid impregnating agents, characterized in that the Wood surrounded by the impregnation liquid, optionally together with it, for the purpose of heating a high frequency field of a wavelength in the centimeter wave range, preferably less than 15 cm, exposes and after the high frequency effects have ceased let the wood cool down within the impregnation liquid. 2. The method according to claim 1, characterized in that that heating and cooling of the wood several times, possibly several times in zones be performed, 3. The method according to claim 1 and 2, characterized in that the heating takes place by an electromagnetic radiation field, the electromagnetic radiation of which is optionally bundled by means known per se such as concave mirrors, horn radiators, lenses. 4. Apparatus for performing the method according to claim 3, characterized by a consisting of a hollow body made of conductive material, in which a Radiation field is generated, except for openings for introducing and discharging or performing the The material to be treated and the supply of electrical energy is closed on all sides. 5. Apparatus for performing the method according to claim 3, characterized by a electromagnetic radiator, which is formed from at least one turn of an electrical conductor is. Considered publications:
German Patent Nos. 886219, 831 767;
Heinzerling: "The Conservierung des Holzes", Halle 1885, p. 118 ff. 1 sheet of drawings © 609740/352 12.56