DE1165836B - Procedure for the complete removal of tree bark - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN WWW PATENT OFFICE Internat. Class: B 271

EDITORIAL

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German class: 38i-l

1 165 836
C12707Ic / 38i
March 14, 1956
March 19, 1964

It is known that the bark of trees is completely removed for numerous industrial purposes got to. In particular in the paper and cellulose industry, it is necessary that the trees with be peeled off with particular care.

To this day, the bark is peeled off the trees either by hand with tools, with carving or smoothing knives or scraping irons or by machine, but in any case mechanically. In addition to increased costs, these methods have the disadvantage that a complete peeling off of the Bark is not reached. Bark rags always remain in the grooves of the trees. This disadvantage cannot be eliminated if the trees are not turned off to a considerable extent, which is always the case some wood is lost to make sure all the bark has been lifted off.

In addition, these mechanical methods can only be used to produce trees with one diameter Use less than about 10 cm, otherwise the cost of peeling off the bark will be too high. aside from that Not all types of wood can be processed in this way, such as hornbeam, because the bark is very firm adheres and does not peel off easily.

Methods of peeling the bark by chemical means have also been proposed. However, these processes have hardly found industrial application because they are too expensive, too difficult and are also harmful to the wood. In fact, in the relevant industry with low, barely changed costs large quantities of wood treated, with a small price fluctuation or a moderate one Change in wood because of the relatively weak importance of the leeway gained in the essential to be neglected.

It is from patent literature 610 954, for example known to debark tree trunks by liquid jets. The ones used in this procedure Temperatures are between 70 and 90 ° C for steam treatment without pressure. The treated Logs are then submerged in water. It should be noted that attempts at Temperatures above 100 ° C do not produce suitable results showed. The experiments described relate generally to a method for treating Tree trunks by heat, whereby it is not specified in which way the heat is generated or brought about will.

Another known method uses steam at feed pressures of 4 to 5 kg / cm ² to remove tree bark. The application of steam occurs at temperatures between 110. Complete Removal Process
of tree bark

Applicant:

LA ROCHETTE CENPA, Societe anonyme,

Paris

Representative:

Dr.-Ing. A. v. Kreisler, Dr.-Ing. K. Schönwald
and Dr.-Ing. Th. Meyer, patent attorneys,
Cologne 1, Deichmannhaus

Named as inventor:

Henri Cassen, Langres (France)

Claimed priority:

France of August 30, 1955 (No. 55 882),

dated January 6, 1956 (No. 56 457 Seine)

and 115 ^C C, the amount of steam supplied can be largely reduced during the treatment in order to set an internal pressure that is sufficient for temperatures between 110 and 115 ° C.

According to this known method, emphasis is placed on the extraction of the bark and not on the extraction laid from bark-free wood, d. i.e., it is not intended that the bark be completely detached of the wood to reach.

The invention relates to a process for the complete removal of tree bark by pretreating the tree trunks by means of saturated steam in an autoclave while avoiding wood browning, which is characterized in that temperatures between 130 and 150 ° C at the corresponding pressures between 2.5 and 5 kg / cm ² can be used for 10 to 30 minutes and then the bark is removed in a known manner by moving and rubbing the logs against one another in a movable container, preferably a rotating debarking drum.

The inventive method, it is possible to obtain a bark-free wood that to Paper can be further processed.

Experience has shown that the critical temperatures and the process conditions that the used Steam should be moist for the success of the

409 539/170

Claims (1)

T'J IiI AI ΙΗΊΊ Ί ί-ί industrial implementation of the process. If you work with dry steam, 'dairfi lets the bark will tear off badly, and it will remain on the wood bark, which the procedure for make the industry uneconomical, because one then "has to" carry out additional treatment get out of the annoying mechanical dismantling ^stands · · ■ .. ■: ·. ■ ;;! / ^ jüLi ^ oiiA If you work at temperatures below C. can the Rinifö '-' with ^i; Valuable AiMaSmtn'-only badly and then only slowly remove. The trees have to be left in the autoclave for several hours, and the process becomes uneconomical because of the increased costs for energy and materials used for a given production. If you work at temperatures above 150 ^c C, you can observe a transformation of the wood, which causes browning. Such a conversion must. must be avoided at all costs so that the maximum possible use of wood in the paper industry can take place. In addition, the bark can also be peeled off in its entirety, since there is no longer any cohesion and it adheres to a certain extent to the wood cell tissue (cambium) that is being formed. Rags remain on the wood that have to be scraped off or pushed off mechanically. As a result, this process loses its main interest for industry, because it is no longer possible to peel off the bark as a whole, completely and quickly. In contrast to this, within the er ■ limits claimed according to the invention, d. H. Between 130 and 150 ° C, and not with moist steam Predictable result that the bark is very quickly in a few minutes, and on the whole, in large pieces and yoHust peel off like that, that "a small application of mechanical force is sufficient to remove the bark from the trees. The length of the peeling process varies according to the type of wood being treated. It was found ddni'döf? "For mei1föBfJü8B ^ äüW a treatment time of about 10 a» l8wfrlinuten is sufficient. For conifers and also white beech, the bark of which is firmer, the bark of which is more firm, 15 to 50 minutes, according to the peeling method than 30 to 35 minutes, and the steam consumption is Mra- is "daVauY pointed out that an essential The advantage of the method according to the invention is that, in contrast to conventional mechanical Process for peeling off bark saves 5 to 10% of the otherwise occurring loss of wood volume will. This represents a significant gain due to the importance of the masses and treated the low value of the otherwise available leeway. For the production of to carry out the method according to ^! All kinds of agents are suitable for use with steam suitable for the invention and for transferring the trees into the treatment zone. ■ '"' Claim: A method for completely removing bark by pretreatment of logs by means of saturated steam in an autoclave under avoidance of a timber browning dadurchgeken, η drawing advised that temperatures between 130 and 150 ° C at those pressures between 2.5 and 5 kg / cm ² 10 to 30 minutes Lang- are applied ¹ and then the bark is removed in a known manner by moving and rubbing the logs against each other in a movable container, preferably a rotating debarking drum. Considered publications:
German Patent No. 610 954;
French patent specification No. 630 691.