DE635561C - Method of drying veneers under pressure - Google Patents

Description

Method of drying veneers under pressure The drying of Veneering has so far been done either by the action of air or in so-called Breathing presses. With the breathing presses, the moist veneer sheet is heated between Press plates laid. It is necessary to switch the heating plates off from time to time take off to account for the shrinkage of the wood and to prevent that the veneer splits and becomes cracked. So that the plates while drying cannot be lifted off by the excess steam pressure or the evacuation of steam is prevented is, channels or grooves are provided in the plates at intervals through which some of the vapors that develop, also remove them when they come into contact with the plates can: The structure of the veneers remains largely unchanged. They have probably given up a substantial part of their water content, the cells but can also absorb water from the air and again after drying swell up. You can therefore on the other hand as a result of external heat influences after Drying. Also release water again. The shape changes due to shrinkage and Swelling causes loosening, throwing up and blistering.

The invention aims at the condition of the veneers through a stretching process change while drying. To do this, the veneers on both sides are through corrugated or profiled heating plates or corrugated or profiled ones by inserting them Sheets between the heating plates. At the points of contact, point- or line-like held, so that a visual twist is prevented during the drying process. The veneers are therefore clamped in this extended or stretched position and retained and no longer return to their original state after drying Shape back. This expansion and stretching of the veneers prevents damage as a result the cell structure of the wood its later absorption of humidity: or its release of moisture or shrinkage and the disadvantages resulting therefrom.

In the drawing, exemplary embodiments of the for executing the Process-serving devices illustrated and shows Fig. T in a schematic Schaubildlicher Dar -stellung two heatable, with corrugations .eeriges press plates one - otherwise known press and the veneer to be dried lying between these.

Fig. 2 is an end view of that in the 'working position Heating plates with the inlaid veneer.

Fig. 3 shows an embodiment in which the corrugations are not are attached to the press plates, but special corrugated surfaces are used.

Figures q: through 6 illustrate various embodiments of the Corrugation.

According to the invention: the wet veneers f during the pressing process between corrugated or profiled heating plates are placed on both sides of the Veneer. act. The profiling can be urx K4 indirectly to the heated pike plates ango # 5 bring no, it can be profiled B @ * «@ between veneer and heating plates @cingele will. In Fig. I, the upper Pneßplatbe a is set up on the underside with profiles or grooves c; the hollow one cut open here; zh lower plate b heated with superheated steam carries the profile on the top. The wet veneer / lies between the two. The vapor plumes developing in the position of the press plates according to FIG. which is not shown to be carried away.

It can also, as shown in Figure 3, corrugated sheets g and h placed between the heating plates a and b and the veneer f and used pressed together with these in the manner described above. The Rifkelüngen itself can be carried out very differently, for. B: as in Fig. Q. until 6 , illustrate: @cht. In particular, the pro- li; erungen interrupted in the longitudinal direction your (Fig. ¢). z - By setting a certain area You can counteract the shrinkage and warping of the shell during the drying process and thereby achieve uniform and effective drying.

Claims (1)

PATENT CLAIM Process for drying kidneys under pressure between heating plates provided with vapor extraction ducts, characterized in that the. Veneers through on both sides. corrugated or profiled heating plates or through Insertion of corrugated or profiled sheets between - the heating plates at the points of contact be held in points or lines to prevent shrinkage during the drying process to prevent.