RU2163539C1 - Method for production of compacted wood - Google Patents

Abstract

FIELD: wood-working industry. SUBSTANCE: method consists in impregnation, thermal treatment and compacting of wood in one hermetically sealed chamber. EFFECT: enhanced quality of wood. 2 cl

Description

 The invention relates to the field of woodworking, namely to the processing of wood by pressure.

 A method of manufacturing plastic products of various sizes [1] is known from analogues of the prior art, including molding the product by casting, and a composition based on elastic rubbers is used as the mold material.

 Also known is the method of elastometric molding [2], including the use of rigid rigging and elastic inserts.

 Closest to the claimed invention by the set of essential features, a prototype, a method of embossing patterns on sheet wooden blanks [3] can be adopted, which consists in pressing treated wood fiber softening liquid between the patterning element and the elastic plate with cord.

 The disadvantage of all the known above methods is the high cost due to the complex technology and low quality of the seal.

 The technical result of the invention is the elimination of these disadvantages.

The technical result is achieved in that the wood is impregnated, heat treated and densified in one sealed chamber, the chamber containing an elastic forming insert of a given configuration with a coefficient of thermal expansion (300-500) · 10 ^-6 1 / ^o C, which when exposed to a step change in temperature heating provides constant programmable regulation of pressure on wood through the membrane. To accelerate the removal of excess moisture and the modifier, a periodic programmable vacuum connection is made.

 The method is as follows. A wooden preform is placed in the lower part of the chamber, the contours of which correspond to the contours of the preform. A relief-forming stamp is placed on top, forming a decorative image on the surface of the workpiece under pressure. A membrane is placed between the upper and lower parts of the chamber, which provides sealing of the mold and the modifying substances are separated from the elastic insert located in the upper part. The lower and upper parts around the perimeter are fixed with fasteners to ensure sealing. Heaters are built into the chamber walls, and the lower part is equipped with a fitting for supplying a modifying substance to the wooden blank and pumping out excess moisture and a modifier.

 As a modifying substance, a urea solution can be used, which is fed to the lower part of the chamber under pressure to impregnate the wood. After impregnation, the excess solution is pumped through the nozzle, a vacuum is created in the lower part of the chamber and the heater is turned on in the chamber walls to carry out the drying process.

When used as a material of an elastic liner of siloxane rubber of the SKTV type, when the temperature reaches 60 ^o C, a pressure of 0.2 MPa is created in the chamber. Periodically pump out excess moisture and a modifier from the workpiece by creating a vacuum in the chamber up to 20 KPa. Then the temperature in the chamber is constantly increased so that the temperature dependence of the liner created by the liner is straightforward, and the pressure during drying and compaction of the wood does not exceed 0.5-0.8 MPa.

At the heat treatment stage, the temperature rises to 180 - 200 ^o C, while a pressure level of up to 50 MPa can be realized. Thus, a birch blank 400 × 600 × 20 in size with an initial moisture content of W = 70% for 7 hours is compacted by 30% and has a final moisture content of W = 10%, with an average deformation rate of 0.25 mm / min. A urea solution of a concentration of 30% was used, impregnation of 30 minutes. The surface quality of the workpiece depends on the quality of the surface of the chamber and the stamp. Color - walnut wood.

 The proposed method allows to obtain high-quality products on inexpensive equipment at low cost. Moreover, the method is very suitable for carrying out the process in programmable mode. To do this, several cameras are connected to the programming device, which are served by one pump for supplying a solution and one vacuum pump with a receiver and a tank for a modifier. It should also be noted that such devices can be placed in the immediate vicinity of logging enterprises, for which it is necessary to have only a source of industrial current. This will significantly reduce the cost of wood products and increase the utilization rate of wood by modifying non-business cheap wood, which is used as waste at forest centers.

Literature
1. Auth. St. USSR N 1164054, 07.22.83.

 2. Vinogradov V.M. and others. Design, calculation and operation of technological equipment for the production of plastic products. - M.: Mechanical Engineering, 1983, p. 142-145.

 3. Auth. St. USSR N 1643187, 05.24.88.

Claims (2)

1. A method of producing compacted wood by saturating it with a modifying fiber softener, followed by heat treatment and compaction in a heating chamber, characterized in that the wood is impregnated, heat treated and compacted in one sealed chamber, the chamber containing an elastic forming insert of a given configuration with a coefficient of thermal expansion (300-500) · 10 ^-6 1 / ^o C, which when exposed to a step change in the heating temperature provides constant programmable control pressure on wood through the membrane.  2. The method according to claim 1, characterized in that to accelerate the removal of excess moisture and the modifier produce a periodic programmed connection of the vacuum.