METHOD AND DEVICE FOR CURVILINEAR FORMATION OF A WODDEN CORRUGATED VENEER

Abstract

 A method for curvilinear formation of the wooden corrugated veneer, in which sliced, rotary cut, eccentrically cut or cut by other similar methods veneer, obtained from wood subjected to hydrothermal treatment at a temperature of 40°C to 80°C depending on the species of wood and absolute humidity above the point of saturation of wood fibers, i.e. above 30%, is formed between two moulds applied on the fluted surfaces of the upper and lower rollers by means of moulds 7 and 8 and is subjected to drying under the climatic conditions of the production room, for which the air temperature is from 20°C to 30°C and the relative humidity is from 35% to 60%, forcing air movement only mechanically. Preferably, the veneer can be dried with the use of blow of dry air at a temperature of 100°C - 150°C and relative humidity of 10%-40% forced into the working space through the air vents in upper cover 11 and lower cover 10, and the process of shape fixation is carried out for several to a dozen or so minutes until the veneer reaches an absolute humidity of approximately 4%, moving the veneer horizontally on the conveyor during this time at a speed of 1 m/min to 10 m/min, depending on the length of the process line and dry air parameters, adjusting the travel speed of drive 9, after which the fixation and relaxation of the stresses in the veneer is carried out between the moulds once they have been unfolded on a flat surface.
The device for curvilinear formation of the wooden corrugated veneer contains fluted rollers 1,2 driven by known drive 9 and placed in a rigid frame 3, and moulds 7, 8 are inserted between rollers 1 and 2, the rollers have an outer diameter most preferably from 10L to 14L, where L corresponds to the length of the pitch (base) of the elementary segment of mould 7, 8. The height of the fluting (tooth) of the mould should preferably be equal from ¼ H to 1/2H of the height of the elementary segment of mould 7, 8, wherein the shape of the fluting should correspond to the shape of mould 7, 8 resulting from proportions of L to H as well as thickness T of the veneer constituting the material for producing the corrugated web, and each mould, lower 7 and upper 8, consists of individual elements articulated together by means of rod rollers 5,6, the concave surfaces of the elements of each mould adhere to contact with the fluted surface of the rollers with the lowest possible coefficient of friction, which cannot exceed 0.1, and rod rollers 5 and 6 during operation enter the recesses of fluted rollers 1 and 2 with the same effect.

Description

[0001] The object of the invention is a method and device for curvilinear formation of a wooden corrugated veneer during the process of continuous production of a dry web of wavy bent veneer from different species of wood. The invention relates in particular to the curvilinear formation of a wet, post-hydrothermally treated, sliced, rotary cut or eccentrically cut veneer that is pressed and at the same time curvilinearly bent into a near-sinusoidal shape.

[0002] The Polish patent PL218202 describes a method for producing honeycomb board blanks used in the furniture carpentry as components for assembling furniture, especially in room or office furniture making, which consist of structures based on support frame slats made of cut raw board, outer boards, and edging. The essential feature of the solution is that first the laminated board is cut on a beam saw according to the gross blank size, then 8-16 mm thick cut blanks are cut out of thickness into two parts on a sawmill machine with an additionally installed vacuum table, then the cut panels are calibrated to a thickness of 4-7 mm on a wide-belt sander upgraded in such a way that it has two steel shafts instead of a steel shaft and rubber shaft; simultaneously, the raw board is cut into slats for the support frame with a thickness of 32 to 100 mm and dimensions of the blanks according to technological needs, and there is stitching of the support frame of the honeycomb board blanks, followed by insertion of the filling in the form of paper honeycomb structure by sewing it into the support frame of the blank, followed by the drilling of holes in the support frame for deaeration, followed by the gluing of calibrated panels on the support frame filled with a paper cell in a multi-ball press machine, the cutting of the glued blank in net size on a tenoner, the veneering of narrow planes on an edge bander with PVC, ABS edging or paper.

[0003] PL174751 presents a method for producing corrugated cardboard that involves heating the upper covering layer and the middle layer of the cardboard to a temperature of approximately 100°C, subjecting the middle layer to additional moistening with steam and corrugating on the surface of a fluting roller at a temperature of approximately 180°C, gluing the wave edges of the middle layer and the upper covering layer together, fixing the resulting adhesive joint at a temperature higher than ambient temperature, then heating the glued layers to a temperature of approximately 80°C, gluing the wave edges of the middle layer and the lower covering layer preheated to approximately 100°C together and fixing the glue bonds of all layers by heating to approximately 120°C, characterized in that individual layers of corrugated cardboard, before they are joined together, as well as the upper covering layer and the middle layer glued together, are heated on both sides inside heat-insulating covers thermally insulating them against contact with atmospheric air; moreover, the heated layers of corrugated cardboard are moved, both to the point where they are glued and to the point where they are bonded together, also inside heat-insulating covers thermally insulating them against contact with atmospheric air.

[0004] PL214286 presents the continuous production of particleboards and fiberboards using a device containing a press drum and a pressure roller for producing the desired initial density of particleboards and fiberboards and a circumferential press belt, in particular a steel belt, by means of which particleboards or fiberboards are flatly pressed against the circumference of the press drum, and also containing a cleaning device which is pushed close to the press belt, and this cleaning device can be pushed into contact with the press belt basically across its entire width. Moreover, this known method for continuous production of particleboards and fiberboards involves applying linear pressure between the press drum and the pressure roller to wet chip or felt webs provided with a binding agent, and additionally applying surface pressure between the circumferential belt and the press belt to produce the desired initial density. The chip material and/or felt material fed in layers to form a mat can be pre-pressed and inserted between the rollers. Such a mat is also referred to as a non-woven sheet or a chip or felt web. The circumferential belt or press belt, especially the steel belt, can be stretched over the rollers. In this case, the chip material is inserted between one or two steel belts. The temperature is provided during pressing. In this procedure, resin is cured. Once it exits the pressing device, the pressed mat as a finished product takes the form of a particleboard, HDF board or MDF board.

[0005] However, the known methods do not allow the curvilinear veneer to be efficiently and continuously produced so that it is possible to use it as a core for the honeycomb board and then produce honeycomb boards with an auxetic core structure. It is also desirable to provide a method for producing a curvilinear veneer that is relatively simple and is a process with limited wood consumption while maximizing the use of low-value wood cutting waste.

[0006] A method for curvilinear formation of a wooden corrugated veneer involves forming the sliced, rotary cut, eccentrically cut, or cut by other similar methods veneer, obtained from wood subjected to hydrothermal treatment at a temperature of 40°C to 80°C depending on the species of wood and absolute humidity above the saturation point of wood fibers, i.e. above 30%, between two moulds applied on the fluted surfaces of the upper and lower rollers. The thickness of the veneer ranges from 1 mm to 2 mm and is inserted between the moulds applied on the fluted rollers. The rollers rotate simultaneously and pull the flat veneer so that it is first bent and then pressed. The diameter of the fluted rollers should be appropriate to the height of the moulds and shaped in such a way that the individual elements of the upper and lower moulds do not collide with each other during rotation. To this end, for an element height of 30 mm and an element base length of 50 mm (height and length values serve demonstrative purposes only), the diameter of the fluted roller should not be less than 600 mm. Once the elements of the upper mould have reached their lowest position and the elements of the lower mould their highest position, the veneer is moved horizontally between the moulds using a drive. During this time, the veneer is subj ected to drying under the climatic conditions of the production room, for which the air temperature is from 20°C to 30°C and the relative humidity is from 35% to 60% by forcing the air movement only mechanically. Preferably, the veneer is dried with the use of the blow of dry air at a temperature of 100°C - 150°C and relative humidity of 10%-40% forced into the working space through air vents in the upper and lower cover. Depending on the species of wood, the process of shape fixation is carried out for several or a dozen or so minutes, i.e. until the veneer reaches an absolute humidity of approximately 4%. During this time, the veneer is moved horizontally on a conveyor at a speed of 1 m/min to 10 m/min, depending on the length of the process line and dry air parameters, adjusting the drive travel speed. Fixation and relaxation of the stresses in the veneer is carried out between the moulds after they have been unfolded on a flat surface. The process of relaxation and subsequent conditioning of the corrugated veneer is considered complete when the veneer reaches a state of hygroscopic equilibrium with the environmental conditions having the relative humidity of approximately 30%-60% and the temperature of approximately 14°C-28°C. During this time, the veneer is preferably moved horizontally on the conveyor at a speed of 1 m/min to 10 m/min, depending on the length of the process line and the air parameters for hygroscopic equilibrium.

[0007] Once conditioned, the veneer can be stacked and subjected to further technological processes.

[0008] The device for the curvilinear formation of the wooden corrugated veneer contains fluted rollers, driven by a known drive and placed in a rigid frame 3, between which the moulds are slidably inserted. The rollers have an outer diameter most preferably of 10L to 14L, where L corresponds to the pitch length (base) of the elementary mould segment. The height of the fluting (tooth) of the mould is preferably from ¼ H to 1/2H of the height of the elementary mould segment, and the shape of the fluting corresponds to the shape of the mould resulting from proportions of L to H as well as thickness T of the veneer constituting the material for producing the corrugated web. Each mould, lower and upper, consists of individual elements articulated together by means of rod rollers. Each element should be perforated to allow the corrugated veneer to come into contact with drying air. The perforations can be of any shape: circular, elliptical, oval, polygonal, etc. The perforations should ensure adequate stiffness of the elements while maintaining their shape and preset dimensional parameters. The ratio of the perforation area to the element area should not be less than ½. The elements may be made of any materials, preferably resistant to dry air at a temperature of 100°C - 150°C and a relative humidity of 10%-40%. The concave surfaces of the elements of each mould adhere to contact [pl. kontaktowo przylegaj

] with the fluted surface of the rollers with the lowest possible coefficient of friction, which cannot exceed 0.1, and the rod rollers during operation enter the recesses of the fluted rollers with the same effect. The distance between the outer surfaces of the mould corresponds to the thickness of the veneer and is preferably adjustable. Preferably, the moulds are made of perforated sheet metal plate, or materials, preferably resistant to dry air at a temperature of 100°C - 150°C and a relative humidity of 10%-40%.

[0009] The diameter of the fluted rollers is matched to the height of the moulds and shaped in such a way that during rotation the individual elements of the upper and lower moulds do not collide with each other. The rollers have an outer diameter most preferably of 10L to 14L, where L corresponds to the pitch length (base) of the elementary mould segment. The height of the fluting (tooth) of the mould is preferably from ¼ H to 1/2H of the height of the elementary mould segment, and the shape of the fluting corresponds to the shape of the mould resulting from proportions of L to H as well as thickness T of the veneer constituting the material for producing the corrugated web.

[0010] A layout of the device for the curvilinear formation of the wooden corrugated veneer is shown in the drawing, where Fig. 1 shows the devices for formation of the corrugated veneer in a single cycle (a) and in continuous work, Fig. 2 shows an isometric view of the rollers and the mould for formation of the corrugated veneer, Fig. 3 shows a side view of the rollers and the mould for formation of the corrugated veneer, Fig. 4 shows a side view of the upper and lower moulds and the dimensions of the mould.

Example

[0011] The method for curvilinear formation of the wooden corrugated veneer involves the sliced, rotary cut, eccentrically cut, or cut by other similar methods veneer that should be used for production. The temperature of the veneer obtained from wood subjected to hydrothermal treatment should be from 40°C and 80°C, depending on the species of wood, and its absolute humidity should be higher than the saturation point of the wood fibers (above 30%). The veneer is formed between two moulds applied on the fluted surfaces of the upper and lower rollers. The thickness of the veneer is from 1 mm to 2 mm and is inserted between moulds 7, 8 applied on fluted rollers 1, 2. The rollers rotate simultaneously and pull the flat veneer so that it is first bent and then pressed. The diameter of the fluted rollers should be appropriate to the height of the moulds and shaped in such a way that the individual elements of the upper and lower moulds do not collide with each other during rotation. To this end, for an element height of 30 mm and an element base length of 50 mm (height and length values serve demonstrative purposes only), the diameter of the fluted roller should not be less than 600 mm. Once the elements of upper mould 8 have reached their lowest position and the elements of lower mould 7 their highest position, the veneer is moved horizontally between moulds 4. During this time, it is subjected to drying under conditions of the blow of dry air at a temperature of 100°C - 150°C and relative humidity of 10%-40%. Depending on the species of wood, the process of shape fixation is carried out for several or a dozen or so minutes, i.e. until the veneer reaches an absolute humidity of approximately 4%. During this time, the veneer is moved horizontally on the conveyor at a speed of 1 m/min to 10 m/min, depending on the length of the process line and dry air parameters. Fixation and relaxation of the stresses in the veneer is carried out between the moulds after they have been unfolded on a flat surface. The process of relaxation and subsequent conditioning of the corrugated veneer is considered complete when the veneer reaches a state of hygroscopic equilibrium with the environmental conditions having the relative humidity of approximately 60% and the temperature of approximately 21°C. During this time, the veneer is preferably moved horizontally on the conveyor at a speed of 1 m/min to 10 m/min, depending on the length of the process line and the air parameters for hygroscopic equilibrium.

[0012] Once conditioned, the veneer can be stacked and subjected to further technological processes.

[0013] The device for the curvilinear formation of the wooden corrugated veneer contains fluted rollers 1,2, driven by a known drive and placed in a rigid frame, between which moulds 7, 8 are slidably inserted. To work properly, the rollers should preferably have an outer diameter of 10L to 14L, where L corresponds to the pitch length (base) of elementary mould segment 7, 8. Preferably, the height of the fluting (tooth) of the mould should be from ¼ H to 1/2H of the height of the elementary segment of mould 7,8, and the shape of the fluting should correspond to the shape of mould 7,8 resulting from proportions of L to H as well as thickness T of the veneer constituting the material for producing the corrugated web. Each mould, lower 7 and upper 8, consists of individual elements articulated together by means of rod rollers 5, 6. Each element should be perforated to allow the corrugated veneer to come into contact with drying air. The perforations can be of any shape: circular, elliptical, oval, polygonal, etc. The perforations should ensure appropriate stiffness of the elements while maintaining their shape and preset dimensional parameters - Fig. 4. The ratio of the perforation area to the element area should not be less than ½. The elements may be made of any materials, preferably resistant to dry air at a temperature of 100°C - 150°C and a relative humidity of 10%-40%. The concave surfaces of the elements of each mould adhere to contact with the fluted surface of the rollers with the lowest possible coefficient of friction, which cannot exceed 0.1, and rod rollers 5, 6 during operation enter the recesses of fluted rollers 1, 2 with the same effect. The distance between the outer surfaces of mould 7 and 8 corresponds to the thickness of the veneer and is preferably adjustable. Preferably, moulds 7 and 8 are made of perforated sheet metal plate.

[0014] The diameter of the fluted rollers is matched to the height of the moulds and shaped in such a way that during rotation the individual elements of the upper and lower moulds do not collide with each other. To work properly, the rollers should have an outer diameter most preferably of 10L to 14L, where L corresponds to the pitch length (base) of elementary mould segment 7, 8. The height of the fluting (tooth) of the mould should be preferably from ¼ H to 1/2H of the height of the elementary segment of mould 7,8, and the shape of the fluting should correspond to the shape of mould 7,8 resulting from proportions of L to H as well as thickness T of the veneer constituting the material for producing the corrugated web.

Claims

1. A method for curvilinear formation of the wooden corrugated veneer, in which sliced, rotary cut, eccentrically cut or cut by other similar methods veneer, obtained from wood subjected to hydrothermal treatment at a temperature of 40°C to 80°C depending on the species of wood and absolute humidity above the point of saturation of wood fibers, i.e. above 30%, is formed between two moulds, characterized in that the formation takes place between two moulds 7 and 8 applied on the fluted surfaces of the upper and lower rollers, the thickness of the veneer is from 1 mm and 2 mm, the rollers rotate simultaneously and pull the flat veneer so that it is first bent and then pressed and the diameter of the fluted rollers is matched to the height of the moulds and shaped in such a way that the rollers have an outer diameter most preferably from 10L to 14L, where L corresponds to the length of the pitch (base) of the elementary segment of mould 7, 8, and once the elements of upper mould 8 have reached the lowest position and the elements of lower mould 7 have reached the highest position, the veneer is moved horizontally between moulds 4 using drive 9 and is subjected to drying under the climatic conditions of the production room for which the air temperature is from 20°C to 30°C and the relative humidity from 35% to 60%, forcing the air movement only mechanically, after which the fixation and relaxation of the stresses in the veneer is carried out between the moulds after they have been unfolded on a flat surface.

2. The method according to claim 1, characterized in that the veneer is dried with the use of the blow of dry air at a temperature of 100°C - 150°C and relative humidity of 10%-40% forced into the working space through the air vents in upper cover 11 and lower 10, and the process of shape fixation is carried out for several or a dozen or so minutes until the veneer reaches an absolute humidity of approximately 4%, moving the veneer horizontally on the conveyor during this time at a speed of 1 m/min to 10 m/min, depending on the length of the process line and dry air parameters, adjusting the travel speed of drive 9.

3. The method according to claims 1 or 2, characterized in that the relaxation process and subsequent conditioning of the corrugated veneer is considered complete when the veneer reaches a state of hygroscopic equilibrium with the environmental conditions-having the relative humidity of approximately 30%-60% and the temperature of approximately 14°C-28°C.

4. The method according to claims 1 or 2 or 3, characterized in that after conditioning the veneer is stacked.

5. The device for curvilinear formation of the wooden corrugated veneer contains fluted rollers 1,2 driven by known drive 9 and placed in a rigid frame 3, characterized in that moulds 7, 8 are inserted between rollers 1 and 2, the rollers have an outer diameter most preferably from 10L to 14L, where L corresponds to the length of the pitch (base) of the elementary segment of mould 7, 8. The height of the fluting (tooth) of the mould should preferably be equal from ¼ H to 1/2H of the height of the elementary segment of mould 7, 8, wherein the shape of the fluting should correspond to the shape of mould 7, 8 resulting from proportions of L to H as well as thickness T of the veneer constituting the material for producing the corrugated web, and each mould, lower 7 and upper 8, consists of individual elements articulated together by means of rod rollers 5,6, the concave surfaces of the elements of each mould adhere to contact with the fluted surface of the rollers with the lowest possible coefficient of friction, which cannot exceed 0.1, and rod rollers 5 and 6 during operation enter the recesses of fluted rollers 1 and 2 with the same effect.

6. The device according to claim 4, characterized in that the distance between the outer surfaces of mould 7 and 8 corresponds to the thickness of the veneer and is adjustable.

7. The device according to claims 4 or 5, characterized in that moulds 7 and 8 are made of perforated sheet metal plate.

Drawing