CS257841B1 - The method of drying the lignocellulosic materials - Google Patents

Abstract

The purpose of the solution is to increase the quality and speed of the refinement of lignocellulosic materials, especially the deep dyeing of peeled and sliced veneers. The stated purpose is achieved by reducing the level of the refined solution by at least 10 cm during the action of the refining solution on the refined material, then increasing it to the original value and repeating this process at least 2 times during the refinement. It is advantageous to reduce the level of the refining solution to below the level of the lower edges of the refined material.

Description

857841

The present invention relates to a method of refining lignocellulosic materials, in particular peeled acrylics, in which the refining solution is applied to the refined material.

Up-to-date methods of refinement are used for bleaching, plasticizing, but not dyeing lignocellulosic materials. There are known methods of deep veneer coloring in sets by simply heating the veneers in a circulating dye solution. In these ways, a high degree of equipment utilization is achieved. This is due mainly to the fact that veneers must be laid by observing a certain free space between the surfaces of the individual leaves. On average per 1 m of veneer ridge is a gap of 3 to 6 mm. The low level of equipment filling results in high water and dye consumption. The use of the described methods for homogeneous refinement combined with considerable demands on wastewater treatment and is demanding on the built-up area.

At higher filling levels, there is an uneven refinement, especially at the junction between the veneers. Therefore, veneer sheets are used for the separation of veneer sheets, such as mesh, stainless steel wire, and fibers, and fabric and mesh of synthetic materials. Handling the spacers increases the laboriousness of these techniques, but does not guarantee perfect refinement. Processes for the treatment of veneer materials are also known which utilize the circulation of the refining solution in a horizontal or vertical direction. In the described methods, the supply of the refining solution is largely dependent on the design of the refining devices. Depending on the type of device, 35% to 60% of the veneers are not refined. Even with a low filling level, sufficient circulation of the refining solution is ensured throughout the device. In order to ensure a more uniform supply of the refining solution to all surfaces, several methods and devices have been developed which are based either on the principle of moving the carriers with the refining solution or by directing the refining solution or the feed gas into the solution.

A disadvantage of the prior art methods to ensure more uniform refinement is the distinctive structural complexity of the devices utilizing these methods, or the inability to easily adapt the devices to the new refining methods. A further disadvantage is the long-time charring which is caused by the insufficient supply of the refining solution to some of the refined material.

The above drawbacks are eliminated by the method of refinement of the invention. This method of refining lignocellulosic materials, in particular peeled and cut veneers, in which the refining solution is applied to the refined material is such that during refining the level of refining solution is reduced by at least 10 cm. Thereafter, the level is raised to baseline and this process is repeated at least 2 times during refinement. It is preferred to lower the leveling solution below the level of the lower edges of the refined material.

Changes in level cause changes in pressures that affect individual veneer locations. This makes it possible to move the veneers in both longitudinal and transverse directions. The advantage of the method of refinement of the invention is in particular the improvement of the penetration of the refining solution to the locations where the veneer sheets are in contact with known refinement methods. Another advantage over known refinement methods is the ease of designing devices utilizing this method and the possibility of adapting already manufactured devices. Example

A dyeing solution is impregnated into the refining vessel, which has an opening for pumping the refining solution at the bottom, and a veneer carrier is inserted. The solution was allowed to act for 30 minutes and then discharged into the container. The container is pumped back into the refining vessel and allowed to soak for 30 minutes. This cycle is repeated until the desired color depth and quality.

Claims (2)

OBJECT OF THE INVENTION Process for the upgrading of lignocellulosic materials, in particular peeled and sliced veneers, in which the quenching solution is applied to the quenching material, characterized in that during the quenching the level of the quenching solution is reduced by at least 10 cm then the level is increased to a baseline value and this process shall be repeated at least 2 times during processing. 2. Process according to claim 1, characterized in that, during the process, the level of the hardening solution is lowered at least once below the level of the lower edges of the treated material.