IL40293A - Apparatus and method for impregnating a corrugated board - Google Patents

Claims (6)

40293/2 WHAT WE CLAIM IS:

1. Apparatus for impregnating a corrugated board characterized by conveyor means for continuously advancing a bundle comprising a plurality of corrugated boards in a given direction, with the fluted channels of said boards in substantially unidirectional alignment throughout said bundle; support means for continuously supporting said board bundle as it advances; compression means for continuously applying to the outer surfaces of the outermost members of said advancing boards bundle a compressive force sufficient to maintain the surfaces of adjoining boards in the bundle in tight abutment as the bundle is advanced, at least a portion of said compression means forming, the walls of a trough, at least in the zone of impregnation, the bottom of said trough being defined by a surface of said advancing bundle which provides access to said aligned fluted channels of said boards, so as to provide communication between said trough walls being in tight abutment against at least the upper portions of the outer surfaces of the outermost members of said bundle; and liquid delivery means for continuously deliver an impregnating liquid into said trough whereupon said liquid passes into the fluted channels of the boards to impregnate the interior surfaces of said boards but without spilling onto the outer surfaces of said boards.

2. The apparatus of claim 1 further characterized by-drying means sequentially following said liquid delivery means for continuously circulating a hot gas through the fluted channels of said board bundle as it continuously advances in order to drive off volatiles contained in the impregnating liquid; curing means sequentially following said drying means for continuously circulating a hot gas through the fluted channels of said board bundle as it continuously advances at a sufficient temperature and for a sufficient time to effectuate curing of the impregnant; and humid fication means sequentially following said curing means for delivering water into the fluted channels of said board bundle as it continuously advances.

3. The apparatus of claim 2 further characterized by gas injection means for passing a gas through said fluted channels of said bundle, said gas injection means being ■ disposed between said liquid delivery means and said drying means, said gas injection means functioning to flush out excess impregnating liquid from said fluted channels.

4. The apparatus of claim 3 characterized in that said conveyor means includes a pair of advancing endless friction belts each disposed to frictionally communicate with at least a portion of the lower outer surfaces of the outermost members of said bundle.

5. The apparatus of claim characterized in that said compression means includes a pair of substantially frictionless advancing endless belts each disposed to communicate with at least a portion of the upper outer surfaces of the outermost members of said bundle, the upper part of each frictionless belt extending beyond the upper outer surface of the outermost board of the bundle with which it communicates to form the walls of a trough, said trough communicating with the fluted channels of the bundle and means for compressing both the friction and frictionless belts against the outermost members of the bundle to maintain all of the members of the bundle in tight surface-to-surface abutment as the bundle continuously advances and to provide a substantially leakproof seal between the frictionless belts and the portions of the upper outer surfaces of the outermost members of the bundle with which they communicate. 6. The apparatus of claim 3 characterized in that said conveyor means includes an advancing endless friction belt disposed to frictionally communicate with at least a portion of the lower outer surface of the bundle; and said compression means includes a flat stationary frictionless plate member and a flat movable frictionless plate member which is movable in a direction perpendicular to that in which said bundle is advancing, each of said plate members disposed to communicate with at least a portion of opposed outer surfaces of the bundle, each of said plate members extending beyond the upper outer surface with which each communicates to define the walls of a trough which communicates with the fluted channels of the bundle; and means for compressing the movable frictionless plate against the outermost member of the bundle with which it communicates to effect compression of the advancing bundle between the stationary plate member and movable plate member. 7. The apparatus of claim 3 characterized in that support means includes an endless advancing open mesh screen belt. 8. The apparatus of claim 3 characterized in that said fluid delivery means includes a constant head reservoir vessel; liquid feed conduit means communicating with said vessel; a liquid dispensing tank disposed above said trough which communicates with the fluted channels of said advancing bundle, said tank provided with at least one bottom opening of controllable dimensions for discharge of fluid into said trough; and conduit means for delivering liquid from said reservoir vessel to said tank. 9. The apparatus of claim 8 characterized in that said support means is an advancing open mesh wire belt and further including a receptacle vessel disposed beneath said advancing bundle and said open mesh wire belt in substantially vertical alignment with said liquid dispensing tank to collect liquid draining from the fluted channels of the advancing bundle and through the open mesh wire belt; and means for recycling the contents of said receptacle vessel to said reservoir vessel. 10. The apparatus of claim characterized in that said liquid dispensing tank contains a flat bottom having disposed therein a plurality of spaced substantially parallel slots, said slots being disposed perpendicularly to the direction in which the bundle is advancing, the width of said slots being substantially that of the advancing bundle, and further including means for adjusting the thickness of said slot to a given 11. The apparatus of claim 3 characterized in that said drying means includes a gas feed conduit communicating with a surface of the advancing bundle which provides access to the fluted channels of the bundles; means for supplying a gas to said gas feed conduit; means for heating said gas; a gas exhaust conduit communicating with a surface of the advancing bundle which provides access to the fluted channels of the bundle but which is opposed to the surface with which said feed conduit communicates, said feed and exhaust conduits being in substantially cooperative alignment on opposed edges of the advancing bundle. 12. The apparatus of claim 11 characterized in that there is provided a plurality of feed and exhaust conduits, -said feed and exhaust conduits alternating on each edge of the bundle to provide a countercurrent circulation through the fluted channels of the bundle. ' · — 13. The apparatus of claim 12 characterized in that said curing means includes a gas feed conduit communicating with an edge of the advancing bundle which provides access -to-the^^ fluted channels of the bundles; means for feeding the gas from the exhaust conduit of said drying means to said curing feed conduit; a gas exhaust conduit communicating with an edge of the advancing bundle which provides access to the fluted channels of the bundle but which is opposed to the edge with which said curing feed conduit communicates, said curing feed and exhaust conduits being in substantially cooperative alignment on opposed edges of the advancing bundle. 40293^. · 14. .'.The apparatus of claim 13 characterized in that said feed conduit of said curing means communicates with said feed conduit of said drying means whereby a portion of the hot gas fed to said drying means is diverted to said feed conduit of said curing means, and further including recirculating conduit means for recirculating at least a portion of the exhaust gas from said drying means to said means for heating said gas and to the feed conduit of said dryer means; and conduit means for supplying dryer exhaust gas to said feed conduit of said curing means, said conduit means communicating at one end with said exhaust conduit of said drying means and with the feed conduit of said curing means at the other end whereby the dryer exhaust gas supplied from said conduit means and a portion of the hot gas fed to the dryer supplied from said recirculating conduit means are

6. 35 The board of claim further characterized by containing paraffin wax in an amount corresponding to about 25$ to 50$ of the weight of the impregnant. £v 36. A corrugated board having enhanced wet rigidity characterized by two cover sheets} each having an internal and external surface, and a fluted medium disposed between said cover sheets and adhesively attached to the internal surfaces of said cover sheets, said fluted medium and said cover sheets being impregnated with a urea-formaldehyde resin in amounts ranging from about to 50$ by weight of the total board weight, the external, surfaces of said cover sheets being substantially free from said urea-formaldehyde impregnant. \ 36 -3837 The hoard of claim -3? characterized the amount of urea-forma!dehyde resin ranges from about 8 to about 20$ by weight of the total board weight, •39·* 38. The board of claim further characterized by containing paraffin wax in an amount corresponding to about 2¾S to 50$ of the weight of the impregnant. 1μΟ·.39. An apparatus for impregnating a corrugated board substantially as described herein with reference to the drawings. J44..40. A method for impregnating a corrugated board substantially as described herein. &.oA A corrugated board having enhanced wet rigidity substantially as described herein with reference to the drawings. Atto cants