Method for the uniform application of foamed liquid mixtures to substrates

摘要

Foamed liquid mixtures are applied to substrates, in particular foamed plywood glues, are spread on traveling wood veneers in the manufacture of plywood by a method comprising the following steps: The liquid is withdrawn from a source of the same, is subjected to a mechanical beating action wherein its density is reduced and is then passed to a reservoir or feed storage vessel. Density-reduced liquid is then foamed and the foam is continuously extruded or otherwise spread on an intermittently-moving substrate during the periods of motion of the substrate. The foamed liquid is continuously diverted from the substrate during the periods of rest of the substrate. The diverted foamed liquid then is defoamed by subjecting it to the same mechanical beating action applied to the liquid thereby increasing its density to substantially that of the density-reduced liquid. Thus, there is obtained a uniform density feed to the foamer making possible a uniform application of foamed liquid on the substrate even though the motion of the substrate is started and stopped at frequent intervals.