US 4,258,088 A · Method for the uniform application of foamed liquid mixtures to substrates

Abstract

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on traveling wood veneers in the manufacture of plywood by a method comprising the following steps: The liquid is withdrawn from a source of the same, is subjected to a mechanical beating action wherein its density is reduced and is then passed to a reservoir or feed storage vessel.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.

Claims11

Dependent claims

A method for the uniform application of a foamed viscous liquid to an intermittently-moving substrate which comprises:

(a) subjecting the raw liquid to a mechanical beating action whereby its density is reduced;
(b) passing said liquid of reduced density to a feed reservoir;
(c) withdrawing liquid from said feed reservoir and passing said liquid to a foamer;
(d) foaming said liquid and passing it to a diversion point while maintaining a constant and predetermined pressure drop between the foamer and diversion point;
(e) passing the foamed liquid from the diversion point to a foam spreader and continuously depositing the foamed liquid as a foam on said intermittently-moving substrate during its period of motion while substantially maintaining said constant and predetermined pressure drop;
(f) diverting the foamed liquid from the diversion point during those periods wherein said intermittently moving substrate is at rest;
(g) subjecting said diverted foamed liquid to a mechanical beating action operable to increase its density to substantially that of said liquid of reduced density while substantially maintaining said constant and predetermined pressure drop, and
(h) passing the mechanically beaten liquid to said feed reservoir.

5 more elements

Dependencies are inferred from the claim text.

Method for the uniform application of foamed liquid mixtures to substrates

Life of this patent

Method for the uniform application of foamed liquid mixtures to substrates

Life of this patent

Abstract

Claims11