GB1410879A - Method of and apparatus for preparing timbers for impregnation with liquid - Google Patents

Abstract

1410879 Preparing timber for impregnation DESOWAG-BAYER HOLZSCHUTZ GmbH 16 July 1973 [19 July 1972] 33811/73 Heading B5L [Also in Division D1] Sawn and squared timber is prepared for impregnation with liquid by incising surfaces of the timber with tracks of grooves such that the grooves of each track are offset relative to adjacent grooves of that track in one of two substantially parallel planes (see Fig. 3) when viewed along that track, the distance between the two planes defining any track being substantially the same as that between the two planes defining any other track. Preferably each groove and track is orientated parallel to the grain, the grooves are of equal length and are spaced at equal intervals in the direction of the track. A suitable apparatus, Figs. 1, 2, comprises set grindable teeth 2 mounted in radial arrangement on a plurality of discs 1 of at least one unit and arranged to incise surfaces of timber with the tracks of grooves. Alternate teeth of each disc are oppositely directed. The discs may be keyed to the shaft in one of two angular positions defined by radii r 1 and r 2 to produce an offset in the setting of the teeth of adjacent discs. The discs of each unit may be separated by spacer discs 5 and fixed to the shaft by clamping plates 7 and nuts 8. Impregnating means may be associated with each unit. In use, each perforation unit may be drawn or pressed forcibly against the timbers by means of a thrust from a spring, or hydraulic or pneumatic elements. By use of several units, preferably two to four, the upper, lower and both side surfaces of a timber may be incised in a single operation. The timbers may be guided through the apparatus by means of suitable feeders, or each unit may be arranged to feed to timber. The impregnating means may comprise a spray tunnel. Alternatively, the impregnating liquid, which may be a preservative, may be applied by a brush or dip coating or an immersion process. Difficultly impregnatable woods such as pinewood and planed timbers, e.g. manufactured wooden structural components, may be treated.