FI108750B - Staplingsmellanskiva - Google Patents

Abstract

Wooden planks (2) are clamped on both sides in a drying apparatus with linear pressure transversely to the grain direction. <IMAGE>

Description

108750

Kerrostusvälilevy

Staplingsmellanskiva 5

FIELD OF THE INVENTION The present invention relates to a deposition spacer forming stacks to be dried! small wood blanks, veneer veneers and the like, which is a spacer formed between the individual veneer veneers.

At present, only two methods are used for drying thin boards, wood veneers or the like, namely continuous drying or one-time drying, for example in a drying chamber. In continuous drying, the board stack is conveyed by a belt conveyor or also by a roller conveyor through a special furnace. This drying is often inadequate, especially in the case of timber of different degrees of dryness or high-density or small-scale timber. In particular, this method will inevitably lead to the rejection of thicker boards or veneers in many applications.

BACKGROUND OF THE INVENTION Prior art using the once-described method is known from DE 882676. U.S. Patent Nos. 3,623,235 and 2,712,699.

• · · · • · · · · ·; . In one-time drying, the boards are stacked in layers using a number of single layers, · · • »·, and the air is circulated through the interleaved spaces between the layers. Such drying implies in automated, ·; · 4 production with very high running costs with relatively low power output. The spacers • · · must be placed relatively narrowly, more or less accurately relative to each other…: at regular intervals to achieve as even drying as possible and to avoid • ♦ • * · *. discarding stacked board layers. Consequently, forming such a stack is j. 30 time consuming work steps. The major disadvantage of this step is that • · ____; in relatively large, generally rectangular spacer support areas · · / moisture removal from the board layers is made more difficult with favorable drying. * ,. conditions cannot be guaranteed.

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It is an object of the invention to provide a layering spacer for use in drying boards or the like so as to guarantee optimal drying conditions and reduce operating costs.

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The invention is characterized in what is set forth in claim 1.

Edge support for boards ensures a minimum support surface and thus improved air circulation around the boards to be dried. Due to the edge support, the wood 10 is subjected to extraordinarily high compression at short intervals, which results in the boards being tightened during drying, while stabilizing their shape and reducing shrinkage, which also contributes to reducing board stresses under varying climatic conditions after drying. Due to the shape stability achieved during drying, the boards have such a straightness that they can be stored for 1 to 15 subsequent processing.

The line pressure on the boards shall be sufficient to prevent the boards from moving freely. However, it should not be large enough to cause permanent indentations on the wood surface. Edge compression is applied in accordance with claim 2 most preferably: · ·: for 20 minutes at 12 mm intervals and according to claim 8 at least 20 g / cm.

• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • according to claim 7. The use of spacers also allows fully automatic stacking. In order for the top layer to be sufficiently loaded with i i · V * 25 also in the higher stack, it is possible to arrange the corresponding tensioning either by strapping the entire stack or by applying a weight load from above.

·; * Using conveyor belts, extra smooth board compression is achieved, which also makes it possible to provide fully automatic board feeding and removal of 30 conveyors. In the case of stacking boards in an intermittent drying process, • the development of baffles into a baffle turns out to be particularly advantageous.

* * * Forming slabs into sheets with support ribs on either side, 3 108750 ensures not only a smooth spacing but also simpler stacking.

In practice, a 1 mm stainless steel or 5 aluminum spacer with 12 mm spacing and 6 mm height has proven to be particularly suitable.

The invention and its various embodiments will be described in more detail below with reference to the drawings.

Figure 1 shows one drying stack used in disposable drying.

Figures 2 and 3 are cross-sectional views of conveyors used in continuous drying.

The board stack shown in Figure 1 has a baffle 1 between two board layers 2. By depositing additional spacers and board layers, a drying load of up to 200 layers can be created.

In the case shown in Fig. 1, the stacking plate 1 is a zig-zag corrugated sheet metal 20 made of stainless steel or aluminum with the upper and::: lowest points of the corrugations serving as support points for the board layers or also for the veneer layers.

These boards are placed on the stacking board such that their texture or • • direction is transverse to the support ribs, which in turn are straight and: edged. Through this the boards are in contact with the edges and their support or I I · *. ' · 25 contact surfaces are minimized, while providing sufficient clearance between the layers for transverse air flow along the supporting ribs. Thus, channels parallel to each other are formed between the laminate and the opposing board layers, which ensure a smooth circulation of the drying medium. The layering plates may have openings (not shown) that ensure the transverse flow of the desiccant medium i · · · »,, f (t '* 30) in the forced recirculation of the desiccant medium and to achieve temperature and humidity equilibrium in the ducts.

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intervals, the result is a longitudinal support of the boards, which helps stabilize their form 4 108750 during drying. The short spacing of the support edges also allows the drying of very short boards. With a distance a between the edges 3 of preferably 12 mm and a height of such a spacer h preferably of 6 mm, excellent efficiency is achieved in terms of shape stability as well as dehumidification and deaeration. This 5 allows the boards, after the drying process, to have a flatness that allows them to be stored for post-treatment.

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The drying stack of boards, which can have up to 200 layers, is subjected to a one-time drying process in the drying chamber which, compared to continuous drying, involves substantially less technical equipment and thus reduces costs.

For reasons of manufacturing technology, the sandwich plate may also be formed so that the peaks of its waves are rounded. In addition to the steel plate, the material of the sandwich plate can be ceramic, plastic or light metal alloys. The board may also be tampered with with various coatings that are resistant to materials that are secreted from the wood during the drying process. In principle, the material, shape, thickness and possibly coating of the baffle can be selected depending on the properties of the boards or veneers to be dried and the height of the stack of boards.

The principle of the invention, which is to tighten boards and veneers on the support edges transverse to the direction of the wood grain during the drying process, is also suitable for use in a continuous process. In this case, the following are used: · two endless, overlapping, spaced apart conveyor belts 4 and 5, with · · · • '· lower or upper part 6,7 in parallel defining a passage zone 8 having a height; ; 25 corresponds to the thickness of the boards 9 fed through it. At the beginning of the lower conveyor belt 4 is a pre-section 10, in the area of which the boards 9 can be placed before being fed into the penetration zone. Similarly, after the penetration zone 8, the conveyor in one ·; * 'End up being an extension.

The conveyors 4 and 5 of Fig. 2 are belts 11 in the zig-zag configuration, the edges 11 of which are in contact with the boards by the desired compression, which can be provided, for example, by: so that the 5 108750 boards on both sides will be affected through the edges 11 with a line pressure of 20 g / cm. The distance between the edges 11, the height of the zig-zag corrugation, and the thickness of the material may be the same as when using the sandwich plates. The compression zone is at least between the beginning and the end of the conveyor in the central part of the drying chamber.

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In the embodiment of Fig. 3, chain conveyors 15 and 16 are provided for transferring the boards, with circular rods 17 for supporting the boards, which, similarly to the conveyor edges shown in Fig. 2, extend transversely to the width of the conveyor belts the compression line pressure transverse to the direction of their causes. The height of the rotary bars, i.e. their diameter, may correspond to the height of the sandwich plate shown in Fig. 1. The same applies to the spacing between the rotary bars a. The loading of the conveyor belt to tighten the boards may be similar to the case shown in Fig. 2.

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Claims (10)

108750 Layering spacer (1) for forming drying stacks of small wood blanks, plywoods and the like, formed as a spacer element between the individual plywood veneers (2), characterized in that the layering spacer (1) has a plurality of support zones (3) by means of which a predetermined line pressure can be applied to the plywood veneer (2), that channels for the drying medium are formed between adjacent support zones (3), and that the layering intermediate plate (1) has openings which allow transverse flow through the drying medium. 10 Layer spacer (1) according to Claim 1, characterized in that the spacing (a) of the support zones (3) is 10-40 mm, preferably 12 mm. Layer spacer (1) according to claim 1 or 2, characterized in that the height (h) of the laminar spacer (1) is 5 to 20 mm, preferably 6 mm. Layering spacer (1) according to one of Claims 1 to 3, characterized in that the laminating spacer (1) is a corrugated board formed by the crimps of the corrugations: support zones (3). V! Laminated intermediate plate (1) according to one of Claims 1 to 4, characterized in that the laminated intermediate plate (1) has zigzag folds. r i Layering spacer (1) according to one of Claims 1 to 5, characterized in that the laminating spacer (1) has rounded waves. Use of a layering spacer (1) according to any one of claims 1 to 6 for drying plywood veneers in a drying chamber, characterized in that the plywood veneers (2) are pressed at positions parallel to each other 30 at a transverse line pressure form. 108750 Use of a layered spacer plate (1) according to claim 7, characterized in that the veneer sheets (2) are pressed in such a way that a minimum line pressure of 20 g / cm is achieved. Use of a sandwich panel (1) according to claim 7 or 8, characterized in that the plywood veneer layers can be stacked up to 200. Use of the deposition spacer (1) according to any one of claims 7 to 9, characterized in that additional pressure is applied from the top to the stack to be dried to achieve a minimum line pressure of 20 g / cm in the top layer. r t t t; i · I »· • * e» 108750