EP0016681B1 - Method of and apparatus for continuously coating sheet material, particularly a paper or cardboard web - Google Patents

Method of and apparatus for continuously coating sheet material, particularly a paper or cardboard web Download PDF

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Publication number
EP0016681B1
EP0016681B1 EP80400306A EP80400306A EP0016681B1 EP 0016681 B1 EP0016681 B1 EP 0016681B1 EP 80400306 A EP80400306 A EP 80400306A EP 80400306 A EP80400306 A EP 80400306A EP 0016681 B1 EP0016681 B1 EP 0016681B1
Authority
EP
European Patent Office
Prior art keywords
blade
web
fact
coating
smoothing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP80400306A
Other languages
German (de)
French (fr)
Other versions
EP0016681A1 (en
Inventor
Pierre Girard
Michel Richard
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Centre Technique de lIndustrie des Papiers Cartons et Celluloses
Original Assignee
Centre Technique de lIndustrie des Papiers Cartons et Celluloses
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from FR7906506A external-priority patent/FR2451418A1/en
Application filed by Centre Technique de lIndustrie des Papiers Cartons et Celluloses filed Critical Centre Technique de lIndustrie des Papiers Cartons et Celluloses
Publication of EP0016681A1 publication Critical patent/EP0016681A1/en
Application granted granted Critical
Publication of EP0016681B1 publication Critical patent/EP0016681B1/en
Expired legal-status Critical Current

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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B05SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05CAPPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05C11/00Component parts, details or accessories not specifically provided for in groups B05C1/00 - B05C9/00
    • B05C11/02Apparatus for spreading or distributing liquids or other fluent materials already applied to a surface ; Controlling means therefor; Control of the thickness of a coating by spreading or distributing liquids or other fluent materials already applied to the coated surface
    • B05C11/04Apparatus for spreading or distributing liquids or other fluent materials already applied to a surface ; Controlling means therefor; Control of the thickness of a coating by spreading or distributing liquids or other fluent materials already applied to the coated surface with blades
    • B05C11/041Apparatus for spreading or distributing liquids or other fluent materials already applied to a surface ; Controlling means therefor; Control of the thickness of a coating by spreading or distributing liquids or other fluent materials already applied to the coated surface with blades characterised by means for positioning, loading, or deforming the blades
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B05SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05CAPPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05C11/00Component parts, details or accessories not specifically provided for in groups B05C1/00 - B05C9/00
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B05SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05CAPPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05C5/00Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work
    • B05C5/02Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work the liquid or other fluent material being discharged through an outlet orifice by pressure, e.g. from an outlet device in contact or almost in contact, with the work
    • B05C5/0245Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work the liquid or other fluent material being discharged through an outlet orifice by pressure, e.g. from an outlet device in contact or almost in contact, with the work for applying liquid or other fluent material to a moving work of indefinite length, e.g. to a moving web
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B05SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05CAPPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05C5/00Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work
    • B05C5/02Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work the liquid or other fluent material being discharged through an outlet orifice by pressure, e.g. from an outlet device in contact or almost in contact, with the work
    • B05C5/0254Coating heads with slot-shaped outlet
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B05SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05CAPPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05C9/00Apparatus or plant for applying liquid or other fluent material to surfaces by means not covered by any preceding group, or in which the means of applying the liquid or other fluent material is not important
    • B05C9/04Apparatus or plant for applying liquid or other fluent material to surfaces by means not covered by any preceding group, or in which the means of applying the liquid or other fluent material is not important for applying liquid or other fluent material to opposite sides of the work
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B05SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05CAPPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05C3/00Apparatus in which the work is brought into contact with a bulk quantity of liquid or other fluent material
    • B05C3/18Apparatus in which the work is brought into contact with a bulk quantity of liquid or other fluent material only one side of the work coming into contact with the liquid or other fluent material

Definitions

  • the present invention relates firstly to a new continuous surface coating process, using a coating composition, of a sheet element such as a sheet of paper, cardboard, or synthetic material. . It also relates to a device allowing the implementation of this method.
  • the surface coating of a sheet element is a common practice in order to improve the qualities of the element, in particular in the case of paper or cardboard.
  • the coating is carried out in a known manner by depositing a coating composition on the sheet element driven in displacement, then by a spreading and smoothing action of the composition in order to obtain a layer thickness also constant as possible.
  • the spreading and smoothing operation is particularly delicate and has been the subject of extensive technical studies with the aim of seeking the elimination of any malformation in the appearance of the layer produced.
  • the known coating method consists in continuously scrolling the sheet element in a determined direction, in particular from bottom to top, between at least two members located on either side.
  • One of these members consisting of a spreading blade, is applied by one end against a face to be coated with the sheet element.
  • the other end of the blade is moved away from the sheet element and directed relative to the first end in a direction opposite to that of the movement of the sheet element.
  • the other member serves as a holding piece for the sheet member and as a reaction piece for the first.
  • the coating composition is deposited in contact with the face to be coated upstream of the zone of application of said spreading blade against the sheet element.
  • a pressing force is exerted on the spreading blade in the direction of the face to be coated so as to spread the coating composition on the face to be coated.
  • the present invention provides a new improvement in these coating methods. Indeed, the Applicant has detected that the coating techniques known up to now have a certain number of unfavorable consequences, on the one hand, at the level of the sheet element and, on the other hand, at the level of the layer of material with which the sheet element is coated.
  • the object of the process according to the present invention is to eliminate the drawbacks mentioned above by reducing the contact time of the coating composition with the sheet element before the spreading and smoothing operation as much as possible.
  • the process can also be used for coating paper in a molten medium, that is to say for the application of hot-melt polymers, paraffins, waxes, hot-melt. It also makes it possible to carry out coatings using pulverulent products subsequently fixed on the support by passage through an oven, for example if it is a hot-melt powder. Coating could also be carried out using foam products.
  • the method of the invention makes it possible to apply the coating composition either on one or on both sides of the sheet element.
  • the method according to the invention is preferably implemented using a known coating device, in particular as described in the aforementioned patent FR-A-2,359,650, in which the element is circulated in sheet between two members, at least one of which is constituted by a smoothing blade subjected to a force urging it towards the second member which can be constituted either by a fixed reaction part, or by a roller on which the element in sheet, either by a second blade arranged in opposition to the first blade.
  • the flexible blade is applied against the sheet element using a flexible tube filled with a pressurized fluid, so as to be bent with a concavity turned towards the outside and tangent to the sheet over a large area.
  • a first variant of use proposed consists of scrolling the sheet element vertically and from top to bottom.
  • the flexible blade is then held at its upper part and applied at its lower part against the sheet element.
  • the angle formed by the sheet element and the blade then forms a natural reservoir inside which a feed nozzle pours the coating composition so as to maintain an amount of excess composition that the sheet passes through.
  • a second variant of use proposed by this document consists in scrolling the sheet element in a direction different from the previous one and, more particularly, from bottom to top. The position of the spreading blade is then modified accordingly.
  • the coating composition is brought and deposited on the sheet element using a nozzle system adjoining it.
  • the sheet element then plays the role of conveyor for the composition which is conveyed to the necking zone where it is smoothed.
  • the contact time between the sheet element and the composition previously smoothed is very long.
  • the composition is either in a state of stagnation or in a state of vortex movement in the vicinity of the sheet element. This is the reason why, according to these methods, the capillary migration is very high and the viscosity of the composition tends to increase considerably before smoothing.
  • the coating composition is channeled into a fluid vein, directed towards the end point of the insertion corner, by means of lateral routing walls.
  • the composition comes from pressurized means which impart to it a total mechanical energy such that the vein which it constitutes is conveyed by pressure effect towards said point in a translational movement continuously oriented along a trajectory progressively approaching that of scrolling of the sheet element.
  • the method according to the invention essentially consists in channeling the coating composition in the form of a fluid vein directed continuously towards the extreme corner of said introduction cone (mentioned above), this by means of two side routing walls located inside this introduction cone, and: following said means for making the composition available under pressure.
  • Another essential means of the process of the invention consists in imparting to the coating composition, by means of said means of provision under pressure, total mechanical energy such that the fluid vein which it constitutes is conveyed by effect pressure towards the extreme corner in a continuously oriented movement along a trajectory progressively approaching that of the scrolling of the sheet element.
  • the fact of injecting the composition in the immediate vicinity of the coating area has the additional advantage of maintaining, within the composition, a state of shear which keeps it fluid until it passes under the blade, thus ensuring a more efficient and homogeneous smoothing and consequently a significantly improved coating quality.
  • this arrangement limits the contact time between the composition and the sheet element previously to its smoothing. This reduces the migration of the liquid phase from the composition to the sheet element and the subsequent tearing of the latter.
  • An important aspect of the invention further lies in the fact that the sheet element is moved in displacement over at least part of its trajectory substantially vertically from bottom to top and that the coating composition is injected also in a direction oriented from bottom to top.
  • This particular arrangement makes it possible to ensure good regularity of the deposition of the coating composition over the entire width of the sheet element while ensuring efficient evacuation of any excess of said composition, without risking the formation of a reserve. as would be the case if one proceeded to an injection from top to bottom with a scrolling of the sheet element in the same direction.
  • the composition is applied, in a manner known per se, by an injector, the outlet orifice of the latter being placed, according to the invention, at or in the immediate vicinity of the area of contact (or smoothing) between the sheet element and the smoothing blade.
  • the outlet of the injector arranged naturally upstream of this zone with respect to the direction of travel of the sheet element, or located at a distance from the outer edge of the blade, as short as possible according to the mechanical requirements imposed by the scrolling of the sheet element and the structure of the injector and oriented towards the top of the angle formed by the blade and the sheet.
  • the invention also relates to a coating device intended to implement the above method.
  • At least one of the members is constituted by a spreading blade. This is applied by one end against a face to be coated with the sheet element. The other end of the blade is moved apart and directed with respect to the first in a direction opposite to that of travel of the sheet element. Finally, the spreading blade is provided with a possible pressure member, associated with the free end of the blade to exert on it a thrust substantially perpendicular to the sheet member, while the rest of the blade has a curvature with convexity turned towards the sheet element.
  • the blade will be constituted by a flexible and thin blade which is elastically deformable and whose free end in contact with the sheet element will be associated with a pressure member ensuring the flatness of the end of the blade in contact with the sheet member and its parallelism with said sheet member.
  • the pressure member may consist of a tube containing a pressurized fluid.
  • the pressure member consists of an elastic counter blade, which may be less flexible than the smoothing blade, located outside the smoothing blade, relative to the element in sheet form, the free end of which rests on the smoothing blade at the point of contact between said smoothing blade and the sheet element.
  • Figure 1 shows in perspective and in section a device for coating a sheet 1 intended for coating a single face of the sheet.
  • Said sheet 1 is driven in displacement in the direction of the arrow by a conventional driving device which has not been shown.
  • the sheet is partially wound on a rotating roller 2.
  • the coating or coating device is generally indicated at 3 and comprises a fixed and hollow box 4, placed under the roller 2, being spaced from it from a distance "e" and the axis 4a of which extends substantially parallel to the axis of the roller and over the entire length of the latter.
  • the internal chamber 5 of the box closed at its ends, is supplied with a coating composition under pressure by a pumping group shown diagrammatically at 6 and connected to a reservoir containing the composition.
  • a slot 7 is made along the length of the box in the vicinity of the roller 2.
  • a flexible blade 8 On one of the edges of the slot is fixed the stationary end of a flexible blade 8, the free end of which is elastically biased in abutment against the sheet 1, downstream of its fixed end in the direction of travel of the sheet, by virtue of the bending of said blade whose convexity is turned towards the roller 2.
  • the arrangement is such that the free end 9 of the blade tangent the curvature of the roller.
  • a pneumatic tube 10 mounted on the body 4 by means of a support 10a (holding the tube over its entire length) exerts pressure over the entire length of the end 9 of the blade.
  • the tube is connected to a source of pressurized air for example, which makes it possible to regulate the pressure exerted on the blade.
  • the fixed end of the blade is spaced from the sheet member and the blade forms with the latter a corner 11. Furthermore, the edges of the slot 7 formed in the box are inclined, from the inside to the outside, in the direction of travel of the sheet element so that they guide, in the direction of the arrow 12, the composition leaving under pressure from the chamber 5 towards the corner 11 formed between the blade and the sheet element. It can be seen that the arrow 12 is oriented substantially 'along the bisector of the angle formed between the blade and the sheet element. It will be noted that the possible excess of coating composition may be evacuated from the corner 1 1 by trickling along arrow 3 on the part of the body located upstream of the slot 7, the fraction of composition thus eliminated being recovered for example in a bin 13 located under the body. The distance "e" between the top of the box and the sheet will be sufficient to allow passage of the excess part of the coating composition while avoiding contact between the latter and the sheet.
  • FIG. 2 represents the general configuration of a coating installation according to the invention.
  • Figure 2 shows the end of a paper making machine which is equipped with a device according to the invention.
  • the two faces of the sheet are coated and, consequently, may have to undergo a pre-drying operation of the layer before the sheet comes into contact with the cylinders 32 and 33. , in order to prevent the still fresh layer from adhering to the cylinders and thereby being deteriorated.
  • first pre-drying element for the face of the sheet intended to come into contact with the roller 28 and in 350 a second pre-drying element for the other face of the sheet.
  • the device according to the invention could only carry out the coating of one of the faces of the sheet and, in this case, we could only provide only one drying system.
  • the sheet element 21 circulates, in the case of Figure 2, vertically from bottom to top.
  • the coating device 130 could consist of one of the variant embodiments which will now be described.
  • the coating device has been produced using two crate assemblies 30 and 30a similar to the crate in FIG. 1 and arranged on either side of a sheet of paper 21 moving roughly vertically from bottom to top.
  • the two body assemblies 30 and 30a are identical and symmetrical with respect to the plane of the sheet 21. It will therefore be sufficient to describe them alone.
  • the box 34 has an internal chamber 35 in which the coating composition supplied under pressure circulates.
  • An inclined slot 37 (serving as an injector) is made in the box and against the wall of the most distant slot of the sheet 21 is fixed one end of a flexible blade 38 elastically deformable.
  • a support 40a fixed on the body 34 supports over its entire length a tube 40 filled with a pressurized fluid (the pressure being adjustable).
  • the two blades 38 are applied on either side of the sheet 21, their free ends being exactly in opposition and forming a zone of contact with the sheet which is parallel to the latter. in order to achieve spreading and smoothing of the layer.
  • the blades are kept under tension one against the other and they therefore have a curvature whose convexity is directed towards the sheet 21, the blades moving away from the sheet from their free end by providing therewith a corner 41.
  • the axis of the slot, materialized by the arrow 42 (which also materializes the path of the vein of coating composition injected into the corner 41 is oriented substantially towards the smoothing zone provided by the free ends of the blades. vein of the composition therefore reaches the sheet immediately upstream of said smoothing zone.
  • FIG 4 there is shown schematically another embodiment in which two blades 50 and 51 are used which are rigid and symmetrical of which only the blade 50 will therefore be described.
  • This rigid blade has a general curvature turned towards the sheet 21 and is pierced with a median channel 52 for admitting the coating composition to the sheet.
  • the channel 52 communicates on the one hand with a source of composition under pressure not shown and opens, on the other hand, at 53 on the free end of the blade, this free end having a flat area 54 and parallel to the sheet 21 which is responsible for spreading and smoothing the layer.
  • the blades can be articulated at their lower ends mounted on a fixed support (not shown) to allow adjustment of the thickness of the layer to be deposited.
  • the example shown in FIG. 4 is the ideal case where the injection of the coating composition and the smoothing take place simultaneously and in the same place.
  • the coating and smoothing device consists of two pairs of blades 60 arranged symmetrically with respect to the vertical sheet 21 and therefore only one will be described.
  • the two blades 61 and 62 of each pair of blades are flexible and elastically deformable. They are also fixed by their lower end in a blade support 63 by screws 64 allowing their removable.
  • the supports 63 are spaced on either side of the sheet 21.
  • the two blades are spaced from one another by a hollow box 65 which is used for the admission under pressure of the coating composition in the direction of the arrow; the box is connected to a composition source (not shown). Due to this arrangement, the two blades 61 and 62 are superimposed and sensitive parallel.
  • the two blades 61 are applied one against the other, under tension, on each side of the sheet 21 and the same is true of the two blades 62.
  • the tension of the blades results of the position of the supports 63.
  • an injector passage 66 making it possible to inject the coating composition between the free ends 67 and 68 of the blades on the sheet 21.
  • at least the free ends 67 of the downstream blades 61 are applied to the sheet so as to be plane and parallel to the sheet.
  • the flatness of these ends is optionally maintained by a pneumatic tube 69 (shown in broken lines) identical to the tubes of FIGS. 1 to 4.
  • FIG. 6 The embodiment of Figure 6 is that which appears to be particularly suitable for industrial use.
  • a fixed structure (not shown) is equipped with two substantially horizontal bars 70, spaced apart and between which a sheet element 21 which is intended to receive a coating composition passes vertically.
  • the coating device consists, as before, of two sets symmetrical with respect to the sheet and of which only one will therefore be described.
  • the support structure 71 On the bar 70 is mounted a support structure 71 capable of tilting and being immobilized around the bar under the action of a position adjustment mechanism (not shown).
  • the support structure 71 has a slide 72 in which a blade holder 73 is engaged which can be locked in the slide by any suitable means.
  • the lower end 74 of a blade 75 is removably fixed in the support, for example by screws 76 in order to allow possible replacement of the blade.
  • the blade 75 is flexible and elastically deformable and when the two structures 71 are in the position shown in FIG. 6, the free ends 77 of the blades are applied to the sheet 21.
  • the blades are kept in this position under tension and therefore have a curvature with convexity turned towards the sheet 21.
  • the blade holders 73 are spaced from the sheet 21 by a distance which can be adjusted by means of the structure 71, which makes it possible to modify the force applying the blade to the sheet and consequently, the thickness of the diaper.
  • each blade is associated with a pneumatic tube 78 containing a pressurized fluid (the pressure of which can be adjusted) and exerting on the end of the blade a pressure whose direction is substantially perpendicular to the sheet, this pressure ensuring the flatness of the end of the blade and its parallelism with the sheet.
  • a pneumatic tube can be carried over its entire length, for example by a support whose arms 79 (shown in broken lines) are fixed to the corresponding blade holder.
  • An injector 80 of coating composition constituted by an elongated hollow box and open at 81 to constitute an injection nozzle is suspended from the structure 71, between the sheet 21 and each of the blades 75.
  • the suspension of the box is constituted by rods 88, one end 82 of which is adjustably engaged in the structure 71 while the other end 83 constitutes a bearing for an axis 84 integral with the box 80.
  • the box is connected to its lower part , via a pipe 85, to a source of coating composition equipped with a pressurized supply system for the box (not shown).
  • the position of the box is adjustable relative to the structure by pivoting around the suspension axes 84 and that once the box placed in a suitable position, it can be locked in this position by any locking system (not shown ) appropriate.
  • the injection nozzle 81 of the box is located as close as possible to the smoothing area reserved between the ends 77 of the blades.
  • the composition is injected directly into the corner formed between each of the blades and the sheet 21 and the injection nozzle is embedded in the product.
  • the possible excess of product is evacuated from the injection zone by trickling onto the face 86 of the box opposite the sheet 21, this face progressively moving away from the sheet.
  • the distance between the nozzle of the injector and the smoothing zone must be as small as possible.
  • the device according to the invention makes it possible to produce both symmetrical coatings as in FIGS. 3 to 6 as well as asymmetrical coatings as in FIGS. 8 and 9.
  • FIG 8 there is shown in solid lines the device according to the invention in which, as in the previous figures, the blades I 1 and I 2 are symmetrical with respect to the sheet element S.
  • the blades I 1 and I 2 are symmetrical with respect to the sheet element S.
  • the blades make the same angle a with respect to the element S, in the case of asymmetry, the blade L 1 forms an angle y and the blade L z an angle ⁇ with the element S.
  • is smaller than y.
  • the L z blade is smoother.
  • the pressure member is not a pneumatic chamber, but, for example, a counter blade (FIGS. 10 to 13), the same asymmetries will obviously be obtained by moving the positions of the lines d under the same conditions. support of the counter blades on the smoothing blades.
  • Figures 10 to 13 show an advantageous means for exerting pressure on the smoothing blade, on the contact zone between this smoothing blade and the paper.
  • the pressing member is constituted by an elastic counterblade situated outside the smoothing blade, and the free end of which is kept applied elastically on the smoothing blade at the point of contact between said smoothing blade and the sheet element.
  • the opposite end is anchored in a movable support so that, when it is tensioned, the counter blade has a curvature with convexity turned towards the sheet element.
  • This counter blade can be made of any suitable flexible material: metal, plastic, etc.
  • the counter blade can be arranged either in the same direction as the corresponding smoothing blade, or in opposite direction, the respective anchoring points of the smoothing blade and the counter blade being, in the latter case, located on either side of the contact area between these two elements.
  • a strip of paper 1 runs from bottom to top, in the direction of the arrow, in a suitable machine.
  • Two smoothing blades 75, 75 'held by supports 73, 73' exert on both sides of the paper strip, at a point 91, a pressure to smooth on each of the two faces a layer of a coating composition .
  • the coating composition is brought between the paper strip and the blade 75, by means of a device not shown such as those described in the previous examples.
  • the flatness of the free end of the blade 75, 75 ′ is ensured by means of a counter blade 83, 83 ′.
  • the blades 83, 83 ' are shorter than the blades 75, 75' which are advantageously very flexible, which also provides a more uniform smoothing effect over the width of the sheet.
  • Each counter blade 83 is anchored in a support 84. Thanks to simple conventional means not shown, the supports 84 can be turned on themselves, and moved vertically (y'y) and horizontally (x'x). It is thus possible to adjust the pressure force, by modifying the curvature of the counter blade, while placing the free edge of the counter blade in the vicinity of the free edge of the smoothing blade.
  • the device comprises the same elements as in FIG. 10 and in addition auxiliary means in the form of pneumatic tubes 78, 78 ′, which can be placed at any point of the counter blade, towards the middle, or towards the free edge. We can then adjust in addition the fluid pressure inside the pneumatic tube and the position of this tube on the counter blade.
  • the device of FIGS. 12 and 13 comprises all the elements of the device of FIG. 10, and in addition a pressure system constituted by a series of segments or fingers 85, arranged along the width of the sheet, and which can be placed so to act on the counter blade at any point situated between the free end of said counter blade and its anchor point.
  • these fingers are adjustable. They can be adjusted one by one, or together, manually or automatically, for example controlled by a device connected to a sensor which detects irregularities in the layer across the width of the sheet, so as to modify the pressure exerted by one or more fingers, depending on the correction to be made to faults detected at their level.
  • the fingers can be mounted in a support 86, which can include all the elements allowing automatic or manual control.
  • inventions of the pressure member described above are particularly suitable for obtaining good straightness and high reliability of the support on the smoothing blades. They also allow, in industrial operation, an easy and precise adjustment of the support line, the latter being well defined and easy to visualize.

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  • Coating Apparatus (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Paper (AREA)
  • Machines For Manufacturing Corrugated Board In Mechanical Paper-Making Processes (AREA)

Description

La présente invention concerne en premier lieu un nouveau procédé d'enduction superficielle en continu, à l'aide d'une composition d'enduction, d'un élément en feuille tel qu'une feuille de papier, de carton, ou de matière synthétique. Elle concerne également un dispositif permettant la mise en oeuvre de ce procédé.The present invention relates firstly to a new continuous surface coating process, using a coating composition, of a sheet element such as a sheet of paper, cardboard, or synthetic material. . It also relates to a device allowing the implementation of this method.

L'enduction superficielle d'un élément en feuille est une pratique courante afin d'améliorer les qualités de l'élément, notamment dans le cas de papier ou de carton. L'enduction est réalisée de manière connue par le dépôt d'une composition d'enduction sur l'élément en feuille entraîné en déplacement, puis par une action d'étalement et de lissage de la composition afin d'obtenir une épaisseur de couche aussi constante que possible. L'opération d'étalement et de lissage est particulièrement délicate et a fait l'objet d'études techniques poussées dans le but de rechercher l'élimination de toute malformation dans l'aspect de la couche produite.The surface coating of a sheet element is a common practice in order to improve the qualities of the element, in particular in the case of paper or cardboard. The coating is carried out in a known manner by depositing a coating composition on the sheet element driven in displacement, then by a spreading and smoothing action of the composition in order to obtain a layer thickness also constant as possible. The spreading and smoothing operation is particularly delicate and has been the subject of extensive technical studies with the aim of seeking the elimination of any malformation in the appearance of the layer produced.

Plus précisément, un procédé d'enduction continu d'un élément en feuille correspondant au préambule de la revendication 1 est déjà connu du brevet FR-A-2.359.650.More specifically, a process for the continuous coating of a sheet element corresponding to the preamble of claim 1 is already known from patent FR-A-2,359,650.

Le procédé d'enduction connu consiste à faire défiler en continu l'élément en feuille dans une direction déterminée, notamment de bas en haut, entre au moins deux organes situés de part et d'autre. L'un de ces organes, constitué par une lame d'étalement, est appliqué par une extrémité contre une face à enduire de l'élément en feuille. L'autre extrémité de la lame est écartée de l'élément en feuille et dirigée par rapport à la première extrémité dans une direction inverse à celle du défilement de l'élément en feuille. L'autre organe sert de pièce de maintien pour l'élément en feuille et de pièce de réaction pour le premier. Selon ce procédé connu, on dépose la composition d'enduction en contact avec la face à enduire en amont de la zone d'application de ladite lame d'étalement contre l'élément en feuille. De plus, on exerce une force de pression sur la lame d'étalement en direction de la face à enduire de manière à assurer l'étalement de la composition d'enduction sur la face à enduire.The known coating method consists in continuously scrolling the sheet element in a determined direction, in particular from bottom to top, between at least two members located on either side. One of these members, consisting of a spreading blade, is applied by one end against a face to be coated with the sheet element. The other end of the blade is moved away from the sheet element and directed relative to the first end in a direction opposite to that of the movement of the sheet element. The other member serves as a holding piece for the sheet member and as a reaction piece for the first. According to this known method, the coating composition is deposited in contact with the face to be coated upstream of the zone of application of said spreading blade against the sheet element. In addition, a pressing force is exerted on the spreading blade in the direction of the face to be coated so as to spread the coating composition on the face to be coated.

La présente invention propose un nouveau perfectionnement de ces méthodes d'enduction. En effet, le Demandeur a décelé que les techniques d'enduction connues jusqu'à présent avaient un certain nombre de conséquences défavorables, d'une part, au niveau de l'élément en feuille et, d'autre part, au niveau de la couche de matière dont est enduit l'élément en feuille.The present invention provides a new improvement in these coating methods. Indeed, the Applicant has detected that the coating techniques known up to now have a certain number of unfavorable consequences, on the one hand, at the level of the sheet element and, on the other hand, at the level of the layer of material with which the sheet element is coated.

Les techniques actuelles procèdent au dépôt de la composition d'enduction à une distance relativement importante de la zone dans laquelle a lieu l'étalement et le lissage. Il en résulte que ladite composition est maintenue au contact de l'élément en feuille pendant un temps relativement important avant que n'intervienne l'étalement. Ainsi, on a constaté que le temps de contact de la composition avec l'élément en feuille variait de 0,01 seconde à 1 seconde suivant que l'on opère avec une coucheuse rapide ou lente. Par suite, dans le cas où l'on utilise une composition d'enduction comportant une phase liquide, il se produit une migration capillaire du liquide dans l'élément en feuille, l'importance de cette migration capillaire pendant ce temps de contact entre la composition et l'élément en feuille précédant le couchage, étant pratiquement identique à celle qui est entraînée par l'opération d'étalement proprement dite provoquée par l'application d'une pression sur la composition d'enduction. Cette migration d'une partie de la phase liquide de la composition d'enduction provoque

  • a) une possible modification (d'ailleurs variable en fonction de la texture de l'élément en feuille) de la structure mécanique et/ou chimique de l'élément en feuille avec les risques de détérioration de ce dernier (rupture, défaut de planéité, etc...);
  • b) une modification corrélative de la composition d'enduction dont la viscosité dans la région où se produit l'étalement va être supérieure à la viscosité initiale de la composition, ce qui peut se traduire par des défauts de régularité de la couche et des difficultés de contrôle de l'opération d'étalement et de lissage.
Current techniques deposit the coating composition at a relatively large distance from the zone in which the spreading and smoothing takes place. As a result, said composition is kept in contact with the sheet element for a relatively long time before spreading occurs. Thus, it was found that the contact time of the composition with the sheet element varied from 0.01 second to 1 second depending on whether one operates with a fast or slow coater. Consequently, in the case where a coating composition comprising a liquid phase is used, there is a capillary migration of the liquid in the sheet element, the extent of this capillary migration during this contact time between the composition and the sheet element preceding the coating, being practically identical to that which is entrained by the actual spreading operation caused by the application of pressure on the coating composition. This migration of part of the liquid phase of the coating composition causes
  • a) a possible modification (moreover variable depending on the texture of the sheet element) of the mechanical and / or chemical structure of the sheet element with the risks of deterioration of the latter (rupture, defect of flatness , etc ...);
  • b) a correlative modification of the coating composition, the viscosity of which in the region where spreading occurs will be greater than the initial viscosity of the composition, which may result in irregularities in the layer and difficulties control of the spreading and smoothing operation.

Les inconvénients relevés ci-dessus se produisent quelles que soient les techniques d'enduction utilisées (enduction par rouleau ou par applicateur à lames).The drawbacks noted above occur regardless of the coating techniques used (roller or blade applicator coating).

Le procédé selon la présente invention a pour objet d'éliminer les inconvénients rappelés ci-dessus en réduisant au maximum le temps de contact de la composition d'enduction avec l'élément en feuille précédant l'opération d'étalement et de lissage.The object of the process according to the present invention is to eliminate the drawbacks mentioned above by reducing the contact time of the coating composition with the sheet element before the spreading and smoothing operation as much as possible.

On notera immédiatement que le procédé selon l'invention peut être utilisé avec des compositions d'enduction de nature quelconque et, dans un grand nombre de domaines industriels.It will immediately be noted that the method according to the invention can be used with coating compositions of any kind and, in a large number of industrial fields.

Ainsi, il est particulièrement adapté au couchage du papier en milieu aqueux ou solvant pour:

  • - l'application de couches pigmentées, afin d'améliorer l'aspect et l'imprimabilité,
  • - l'encollage en vue de renforcer les propriétés mécaniques ou d'autres propriétés particulières d'un support (propriétés diélectriques, conductrices, anti-adhésives, etc...); les compositions utilisées peuvent comporter par exemple de l'amidon, des dérivés cellulosiques, de l'alcool polyvinylique, des dispersions plastiques (acétate de polyvinyle, latex styrène-butadiène ou copolymères acryliques), résines diélectriques, polymères conducteurs, silicones, vernis et laques diverses.
Thus, it is particularly suitable for coating paper in an aqueous or solvent medium for:
  • - the application of pigmented layers, in order to improve the appearance and the printability,
  • - gluing in order to reinforce the mechanical properties or other specific properties of a support (dielectric, conductive, non-stick properties, etc.); the compositions used can comprise for example starch, cellulose derivatives, polyvinyl alcohol, plastic dispersions (polyvinyl acetate, styrene-butadiene latex or acrylic copolymers), dielec resins triques, conductive polymers, silicones, varnishes and various lacquers.

Le procédé peut également être utilisé pour le couchage du papier en milieu fondu, c'est-à-dire pour l'application de polymères thermo- fusibles, de paraffines, de cires, de hot-melt. Il permet aussi de procéder à des enductions à l'aide de produits pulvérulents fixés ultérieurement sur le support par passage dans un four, par exemple s'il s'agit d'une poudre thermo- fusible. On pourrait également procéder à l'enduction à l'aide de produits à l'état de mousse.The process can also be used for coating paper in a molten medium, that is to say for the application of hot-melt polymers, paraffins, waxes, hot-melt. It also makes it possible to carry out coatings using pulverulent products subsequently fixed on the support by passage through an oven, for example if it is a hot-melt powder. Coating could also be carried out using foam products.

Par ailleurs, le procédé de l'invention permet d'appliquer la composition d'enduction soit sur l'une, soit sur les deux faces de l'élément en feuille.Furthermore, the method of the invention makes it possible to apply the coating composition either on one or on both sides of the sheet element.

Le procédé selon l'invention est mis en oeuvre de préférence à l'aide d'un dispositif d'enduction connu, notamment tel que décrit dans le brevet précité FR-A-2.359.650, dans lequel on fait circuler l'élément en feuille entre deux organes dont l'un au moins est constitué par une lame de lissage soumise à une force la sollicitant vers le deuxième organe qui peut être constitué soit par une pièce de réaction fixe, soit par un rouleau sur lequel s'enroule l'élément en feuille, soit encore par une deuxième lame disposée en opposition avec la première lame.The method according to the invention is preferably implemented using a known coating device, in particular as described in the aforementioned patent FR-A-2,359,650, in which the element is circulated in sheet between two members, at least one of which is constituted by a smoothing blade subjected to a force urging it towards the second member which can be constituted either by a fixed reaction part, or by a roller on which the element in sheet, either by a second blade arranged in opposition to the first blade.

C'est, en effet, avec ce type de dispositif que le procédé selon l'invention fournit les résultats optimum.It is, in fact, with this type of device that the method according to the invention provides the optimum results.

Selon ce document, il est recommandé d'utiliser une lame souple d'enduction et de soumettre son extrémité à une poussée s'exerçant perpendiculairement de façon à appliquer la lame contre l'élément en feuille.According to this document, it is recommended to use a flexible coating blade and to subject its end to a thrust acting perpendicularly so as to apply the blade against the sheet element.

Selon un mode de mise en oeuvre recommandé par ce document, la lame souple est appliquée contre l'élément en feuille à l'aide d'un tube souple rempli d'un fluide sous pression, de façon à être courbée avec une concavité tournée vers l'extérieur et tangente à la feuille selon une surface importante.According to an embodiment recommended by this document, the flexible blade is applied against the sheet element using a flexible tube filled with a pressurized fluid, so as to be bent with a concavity turned towards the outside and tangent to the sheet over a large area.

Une première variante d'utilisation proposée consiste à faire défiler l'élément en feuille verticalement et de haut en bas. La lame souple est alors maintenue à sa partie supérieure et appliquée à sa partie inférieure contre l'élément en feuille. L'angle formé par l'élément en feuille et la lame forme alors un réservoir naturel à l'intérieur duquel une buse d'alimentation déverse la composition de couchage de façon à maintenir une quantité de composition en excès que la feuille traverse.A first variant of use proposed consists of scrolling the sheet element vertically and from top to bottom. The flexible blade is then held at its upper part and applied at its lower part against the sheet element. The angle formed by the sheet element and the blade then forms a natural reservoir inside which a feed nozzle pours the coating composition so as to maintain an amount of excess composition that the sheet passes through.

Une seconde variante d'utilisation proposée par ce document consiste à faire défiler l'élément en feuille dans une direction différente de la précédente et, plus particulièrement, de bas en haut. La position de la lame d'étalement est alors modifiée en conséquence. La composition de couchage est amenée et déposée sur l'élément en feuille à l'aide d'un système de buse le jouxtant. L'élément en feuille joue alors le rôle de convoyeur pour la composition qui est acheminée vers la zone de striction où elle est lissée.A second variant of use proposed by this document consists in scrolling the sheet element in a direction different from the previous one and, more particularly, from bottom to top. The position of the spreading blade is then modified accordingly. The coating composition is brought and deposited on the sheet element using a nozzle system adjoining it. The sheet element then plays the role of conveyor for the composition which is conveyed to the necking zone where it is smoothed.

Ainsi, selon les enseignements de ce document, la composition est

  • - soit déversée par gravité et brassée de façon désordonnée, au voisinage de l'élément en feuille,
  • - soit simplement déposée et transportée par l'élément en feuille avant couchage.
Thus, according to the teachings of this document, the composition is
  • - either poured by gravity and stirred in a disorderly manner, in the vicinity of the sheet element,
  • - either simply deposited and transported by the sheet element before coating.

Dans les deux cas et de même que dans tous les dispositifs connus, le temps de contact entre l'élément en feuille et la composition précédemment au lissage est très long. De plus, la composition se trouve soit en état de stagnation, soit en état de mouvement tourbillonnaire au voisinage de l'élément en feuille. C'est la raison pour laquelle, selon ces procédés, la migration capillaire est très importante et la viscosité de la composition a tendance à croître considérablement avant le lissage.In both cases and as in all known devices, the contact time between the sheet element and the composition previously smoothed is very long. In addition, the composition is either in a state of stagnation or in a state of vortex movement in the vicinity of the sheet element. This is the reason why, according to these methods, the capillary migration is very high and the viscosity of the composition tends to increase considerably before smoothing.

Au contraire, selon la forme la plus générale de l'invention, on canalise la composition d'enduction en une veine fluide, dirigée vers le point extrême du coin d'introduction, par l'intermédiaire de parois latérales d'acheminement. La composition est issue de moyens de mise à disposition sous pression qui lui impriment une énergie mécanique totale telle que la veine qu'elle constitue soit acheminée par effet de pression vers ledit point en un mouvement de translation continuellement orienté suivant une trajectoire se rapprochant progressivement de celle de défilement de l'élément en feuille.On the contrary, according to the most general form of the invention, the coating composition is channeled into a fluid vein, directed towards the end point of the insertion corner, by means of lateral routing walls. The composition comes from pressurized means which impart to it a total mechanical energy such that the vein which it constitutes is conveyed by pressure effect towards said point in a translational movement continuously oriented along a trajectory progressively approaching that of scrolling of the sheet element.

Plus précisément, le procédé selon l'invention consiste essentiellement à canaliser la composition d'enduction sous la forme d'une veine fluide dirigée continûment vers le coin extrême dudit cône d'introduction (évoqué plus haut), ceci par l'intermédaire de deux parois latérales d'acheminement situées à l'intérieur de ce cône d'introduction, et :ssue dudit moyen de mise à disposition sous pression de la composition.More specifically, the method according to the invention essentially consists in channeling the coating composition in the form of a fluid vein directed continuously towards the extreme corner of said introduction cone (mentioned above), this by means of two side routing walls located inside this introduction cone, and: following said means for making the composition available under pressure.

Un autre moyen essentiel du procédé de l'invention consiste à imprimer à la composition d'enduction, par l'intermédiaire dudit moyen de mise à disposition sous pression, une énergie mécanique totale telle que la veine fluide qu'elle constitue soit acheminée par effet de pression vers le coin extrême en un mouvement continûment orienté suivant une trajectoire se rapprochant progressivement de celle du défilement de l'élément en feuille.Another essential means of the process of the invention consists in imparting to the coating composition, by means of said means of provision under pressure, total mechanical energy such that the fluid vein which it constitutes is conveyed by effect pressure towards the extreme corner in a continuously oriented movement along a trajectory progressively approaching that of the scrolling of the sheet element.

On notera que le fait d'injecter la composition au voisinage immédiat de la zone de couchage présente l'avantage supplémentaire d'entretenir, au sein de la composition, un état de cisaillement qui lui conserve sa fluidité jusqu'au passage sous la lame, assurant ainsi un lissage plus efficace et homogène et par suite une qualité de couchage sensiblement améliorée.It will be noted that the fact of injecting the composition in the immediate vicinity of the coating area has the additional advantage of maintaining, within the composition, a state of shear which keeps it fluid until it passes under the blade, thus ensuring a more efficient and homogeneous smoothing and consequently a significantly improved coating quality.

On remarquera, en outre, que cette disposition limite le temps de contact entre la composition et l'élément en feuille précédemment à son lissage. On diminue de ce fait la migration de la phase liquide de la composition vers l'élément en feuille et les déchirements consécutifs de cette dernière.Note, moreover, that this arrangement limits the contact time between the composition and the sheet element previously to its smoothing. This reduces the migration of the liquid phase from the composition to the sheet element and the subsequent tearing of the latter.

Un aspect important de l'invention réside en outre dans le fait que l'on entraîne en déplacement l'élément en feuille sur au moins une partie de sa trajectoire sensiblement verticalement de bas en haut et que l'on injecte la composition d'enduction également selon une direction orientée de bas en haut. Cette disposition particulière permet d'assurer une bonne régularité du dépôt de la composition d'enduction sur toute la largeur de l'élément en feuille en assurant une évacuation efficace de l'excès éventuel de ladite composition, sans risquer de voir se former une réserve comme ce serait le cas si l'on procédait à une injection de haut en bas avec un défilement de l'élément en feuille dans la même direction.An important aspect of the invention further lies in the fact that the sheet element is moved in displacement over at least part of its trajectory substantially vertically from bottom to top and that the coating composition is injected also in a direction oriented from bottom to top. This particular arrangement makes it possible to ensure good regularity of the deposition of the coating composition over the entire width of the sheet element while ensuring efficient evacuation of any excess of said composition, without risking the formation of a reserve. as would be the case if one proceeded to an injection from top to bottom with a scrolling of the sheet element in the same direction.

Selon un autre aspect de l'invention, la composition est appliquée, de façon connue en soi, par un injecteur, l'orifice de sortie de ce dernier étant placé, selon l'invention, au niveau ou au voisinage immédiat de la zone de contact (ou de lissage) entre l'élément en feuille et la lame de lissage.According to another aspect of the invention, the composition is applied, in a manner known per se, by an injector, the outlet orifice of the latter being placed, according to the invention, at or in the immediate vicinity of the area of contact (or smoothing) between the sheet element and the smoothing blade.

Dans le cas où la composition d'enduction ne peut être appliquée exactement au niveau de la zone de lissage, on fait en sorte que la sortie de l'injecteur, disposée naturellement en amont de cette zone par rapport au sens de défilement de l'élément en feuille, soit située à une distance du bord extérieur de la lame, la plus courte possible en fonction des nécessités mécaniques imposées par le défilement de l'élément en feuille et la structure de l'injecteur et orientée vers le sommet de l'angle formé par la lame et la feuille.In the case where the coating composition cannot be applied exactly at the level of the smoothing zone, it is ensured that the outlet of the injector, arranged naturally upstream of this zone with respect to the direction of travel of the sheet element, or located at a distance from the outer edge of the blade, as short as possible according to the mechanical requirements imposed by the scrolling of the sheet element and the structure of the injector and oriented towards the top of the angle formed by the blade and the sheet.

Mais l'invention concerne également un dispositif d'enduction destiné à mettre en oeuvre le procédé ci-dessus.However, the invention also relates to a coating device intended to implement the above method.

L'art antérieur le plus proche du dispositif de l'invention est décrit dans le brevet précité FR-A-2.359.650, dont les caractéristiques principales connues correspondent au préambule de la revendication 5 de la présente demande.The closest prior art to the device of the invention is described in the aforementioned patent FR-A-2,359,650, the main known characteristics of which correspond to the preamble of claim 5 of the present application.

Le dispositif décrit dans ce document comporte:

  • - un système de guidage et de défilement en continu de l'élément en feuille,
  • - un moyen pour déposer ladite composition d'enduction
  • - et deux organes entre lesquels circule l'élément en feuille.
The device described in this document comprises:
  • - a system for continuously guiding and scrolling the sheet element,
  • a means for depositing said coating composition
  • - And two organs between which the sheet element circulates.

L'un au moins des organes est constitué par une lame d'étalement. Celle-ci est appliquée par une extrémité contre une face à enduire de l'élément en feuille. L'autre extrémité de la lame est écartée et dirigée par rapport à la première dans une direction inverse par rapport à celle de défilement de l'élément en feuille. Enfin, la lame d'étalement est munie d'un éventuel organe de pression, associé à l'extrémité libre de la lame pour exercer sur celle-ci une poussée sensiblement perpendiculaire à l'élément en feuille, tandis que le reste de la lame présente une courbure à convexité tournée vers l'élément en feuille.At least one of the members is constituted by a spreading blade. This is applied by one end against a face to be coated with the sheet element. The other end of the blade is moved apart and directed with respect to the first in a direction opposite to that of travel of the sheet element. Finally, the spreading blade is provided with a possible pressure member, associated with the free end of the blade to exert on it a thrust substantially perpendicular to the sheet member, while the rest of the blade has a curvature with convexity turned towards the sheet element.

Par rapport à ce dispositif connu du brevet FR-A-2.359.650, le dispositif d'enduction selon l'invention est remarquable par le fait que son moyen de dépôt de la composition d'enduction possède un orifice de sortie formant injecteur. En outre, une caractéristique essentielle est que

  • - d'une part, l'orifice de sortie est situé entre les deux extrémités de la lame, au voisinage de l'extrémité de celle-ci en contact avec l'élément en feuille
  • - et, d'autre part, l'injecteur est dirigé vers le sommet de l'angle entre l'élément en feuille et la lame.
Compared to this device known from patent FR-A-2,359,650, the coating device according to the invention is remarkable in that its means for depositing the coating composition has an outlet opening forming an injector. In addition, an essential feature is that
  • - on the one hand, the outlet orifice is located between the two ends of the blade, in the vicinity of the end of the latter in contact with the sheet element
  • - And, on the other hand, the injector is directed towards the top of the angle between the sheet element and the blade.

On précisera simplement que, de préférence, la lame sera constituée par une lame souple et mince élastiquement déformable et dont l'extrémité libre en contact avec l'élément en feuille sera associée à un organe de pression assurant la planéité de l'extrémité de la lame en contact avec l'élément en feuille et son parallélisme avec ledit élément en feuille.It will simply be specified that, preferably, the blade will be constituted by a flexible and thin blade which is elastically deformable and whose free end in contact with the sheet element will be associated with a pressure member ensuring the flatness of the end of the blade in contact with the sheet member and its parallelism with said sheet member.

L'organe de pression peut consister en un tube contenant un fluide sous pression. Selon un mode de réalisation avantageux de l'invention, l'organe de pression consiste en une contre-lame élastique, pouvant être moins souple que la lame de lissage, située à l'extérieur de la lame de lissage, par rapport à l'élément en feuille, et dont l'extrémité libre appuie sur la lame de lissage au point de contact entre ladite lame de lissage et l'élément en feuiile.The pressure member may consist of a tube containing a pressurized fluid. According to an advantageous embodiment of the invention, the pressure member consists of an elastic counter blade, which may be less flexible than the smoothing blade, located outside the smoothing blade, relative to the element in sheet form, the free end of which rests on the smoothing blade at the point of contact between said smoothing blade and the sheet element.

On décrira à présent, à titre d'exemples non limitatifs, plusieurs formes de réalisation de l'invention en référence aux dessins annexés dans lesquels:

  • - La figure 1 représente une première forme de réalisation d'un dispositif selon l'invention, constitué d'un rouleau coopérant avec une lame de lissage;
  • - La figure 2 est une vue en perspective schématique d'une installation d'un système d'enduction utilisant une structure selon les figures 3 à 7;
  • - La figure 3 est un exemple de réalisation d'un dispositif d'enduction à deux lames;
  • - Les figures 4 et 5 représentent schématiquement deux variantes de réalisation du dispositif d'enduction;
  • - La figure 6 représente une forme avantageuse de réalisation de l'invention;
  • - La figure 7 est un schéma explicatif;
  • - Les figures 8 et 9 montrent le montage du dispositif permettant une dissymétrie du couchage des faces de l'élément en feuille;
  • - La figure 10 représente une vue en coupe schématique, perpendiculaire à l'arête des lames d'un dispositif d'enduction double face selon l'invention;
  • - Les figures 11 et 12 sont des vues analogues à la figure 10 pour une variante; et
  • - La figure 13 est une vue schématique en perspective du dispositif de la figure 12.
Several embodiments of the invention will now be described, by way of nonlimiting examples, with reference to the appended drawings in which:
  • - Figure 1 shows a first embodiment of a device according to the invention, consisting of a roller cooperating with a smoothing blade;
  • - Figure 2 is a schematic perspective view of an installation of a coating system using a structure according to Figures 3 to 7;
  • - Figure 3 is an embodiment of a coating device with two blades;
  • - Figures 4 and 5 schematically represent two alternative embodiments of the coating device;
  • - Figure 6 shows an advantageous embodiment of the invention;
  • - Figure 7 is an explanatory diagram;
  • - Figures 8 and 9 show the mounting of the device allowing an asymmetry of the coating of the faces of the sheet element;
  • - Figure 10 shows a schematic sectional view, perpendicular to the edge of the blades of a double-sided coating device according to the invention;
  • - Figures 11 and 12 are views similar to Figure 10 for a variant; and
  • - Figure 13 is a schematic perspective view of the device of Figure 12.

Pour faciliter la description des formes de réalisation ci-après, on considérera que l'on souhaite coucher une feuille de papier et, par conséquent, on parlera d'une feuille de papier, d'une composition de couchage et, de manière générale, d'un système de couchage.To facilitate the description of the embodiments below, it will be considered that one wishes to lay down a sheet of paper and, consequently, one will speak of a sheet of paper, of a coating composition and, in general, a sleeping system.

Il est évident cependant que ceci ne constitue pas une limitation de l'invention et que, dans le cas où l'on souhaiterait traiter autre chose qu'une feuille de papier, de carton ou de non-tissé, et notamment un film de matière plastique ou un tissu en bande, il suffira d'effectuer une adaptation des moyens de l'invention qui est à la portée du technicien.It is obvious, however, that this does not constitute a limitation of the invention and that, in the case where it is desired to treat something other than a sheet of paper, cardboard or nonwoven, and in particular a film of material plastic or strip fabric, it will suffice to carry out an adaptation of the means of the invention which is within the reach of the technician.

La figure 1 représente en perspective et en coupe un dispositif de couchage d'une feuille 1 destiné à l'enduction d'une seule face de la feuille. Ladite feuille 1 est entraînée en déplacement dans le sens de la flèche par un dispositif d'entraînement classique que l'on n'a pas représenté. La feuille s'enroule partiellement sur un rouleau tournant 2. Le dispositif d'enduction ou de couchage est indiqué de façon générale en 3 et comprend une caisse 4 fixe et creuse, disposée sous le rouleau 2 en étant écartée de celui-ci d'une distance "e" et dont l'axe 4a s'étend sensiblement parallèlement à l'axe du rouleau et sur toute la longueur de celui-ci. La chambre interne 5 de la caisse, fermée à ses extrémités, est alimentée en composition d'enduction sous pression par un groupe de pompage représenté schématiquement en 6 et relié à un réservoir contenant la composition. Une fente 7 est pratiquée sur la longueur de la caisse au voisinage du rouleau 2. Sur un des bords de la fente est fixée l'extrémité immobile d'une lame souple 8, dont l'extrémité libre est sollicitée élastiquement en appui contre la feuille 1, en aval de son extrémité fixe dans le sens de défilement de la feuille, grâce à la flexion de ladite lame dont la convexité est tournée vers le rouleau 2. La disposition est telle que l'extrémité libre 9 de la lame tangente la courbure du rouleau. Pour assurer la planéité de la partie 9 de la lame en contact avec l'élément en feuille, un tube pneumatique 10 monté sur la caisse 4 par l'intermédiaire d'un support 10a (maintenant le tube sur toute sa longueur) exerce une pression sur toute la longueur de l'extrémité 9 de la lame. Le tube est raccordé à une source d'air sous pression par exemple, ce qui permet de régler la pression s'exerçant sur la lame.Figure 1 shows in perspective and in section a device for coating a sheet 1 intended for coating a single face of the sheet. Said sheet 1 is driven in displacement in the direction of the arrow by a conventional driving device which has not been shown. The sheet is partially wound on a rotating roller 2. The coating or coating device is generally indicated at 3 and comprises a fixed and hollow box 4, placed under the roller 2, being spaced from it from a distance "e" and the axis 4a of which extends substantially parallel to the axis of the roller and over the entire length of the latter. The internal chamber 5 of the box, closed at its ends, is supplied with a coating composition under pressure by a pumping group shown diagrammatically at 6 and connected to a reservoir containing the composition. A slot 7 is made along the length of the box in the vicinity of the roller 2. On one of the edges of the slot is fixed the stationary end of a flexible blade 8, the free end of which is elastically biased in abutment against the sheet 1, downstream of its fixed end in the direction of travel of the sheet, by virtue of the bending of said blade whose convexity is turned towards the roller 2. The arrangement is such that the free end 9 of the blade tangent the curvature of the roller. To ensure the flatness of the part 9 of the blade in contact with the sheet element, a pneumatic tube 10 mounted on the body 4 by means of a support 10a (holding the tube over its entire length) exerts pressure over the entire length of the end 9 of the blade. The tube is connected to a source of pressurized air for example, which makes it possible to regulate the pressure exerted on the blade.

Comme on peut le voir sur la figure 1, l'extrémité fixe de la lame est écartée de l'élément en feuille et la lame forme avec ce dernier un coin 11. Par ailleurs, les bords de la fente 7 ménagée dans la caisse sont inclinés, de l'intérieur vers l'extérieur, dans le sens de défilement de l'élément en feuille de telle sorte qu'ils réalisent un guidage, dans le sens de la flèche 12, de la composition sortant sous pression de la chambre 5 en direction du coin 11 formé entre la lame et l'élément en feuille. On peut constater que la flèche 12 est orientée sensiblement 'selon la bissectrice de l'angle formé entre la lame et l'élément en feuille. On notera que l'éventuel excès de composition d'enduction pourra s'évacuer du coin 1 1 en ruisselant selon la flèche 3 sur la partie de la caisse située en amont de la fente 7, la fraction de composition ainsi éliminée étant récupérée par exemple dans un bac 13 situé sous la caisse. La distance "e" entre le sommet de la caisse et la feuille sera suffisante pour permettre le passage de la partie en excès de la composition d'enduction tout en évitant un contact entre celle-ci et la feuille.As can be seen in Figure 1, the fixed end of the blade is spaced from the sheet member and the blade forms with the latter a corner 11. Furthermore, the edges of the slot 7 formed in the box are inclined, from the inside to the outside, in the direction of travel of the sheet element so that they guide, in the direction of the arrow 12, the composition leaving under pressure from the chamber 5 towards the corner 11 formed between the blade and the sheet element. It can be seen that the arrow 12 is oriented substantially 'along the bisector of the angle formed between the blade and the sheet element. It will be noted that the possible excess of coating composition may be evacuated from the corner 1 1 by trickling along arrow 3 on the part of the body located upstream of the slot 7, the fraction of composition thus eliminated being recovered for example in a bin 13 located under the body. The distance "e" between the top of the box and the sheet will be sufficient to allow passage of the excess part of the coating composition while avoiding contact between the latter and the sheet.

Naturellement, on comprendra que la forme de la caisse ainsi que le système d'alimentation de la composition pourraient être différents sans qu'on sorte du cadre de l'invention. De même, on pourrait prévoir une autre disposition de la caisse par rapport au rouleau, dès lors que la caisse se trouvera localisée dans la région de la demi-circonférence inférieure du rouleau. Enfin, au lieu d'une fente 7 continue, on pourrait prévoir dans la caisse une série de passages séparés les uns des autres.Naturally, it will be understood that the shape of the box as well as the system for supplying the composition could be different without departing from the scope of the invention. Similarly, one could provide another arrangement of the box relative to the roller, as soon as the box is located in the region of the lower half-circumference of the roller. Finally, instead of a continuous slot 7, one could provide in the box a series of separate passages from each other.

Les formes de réalisation qu'on décrira à présent assurent l'enduction simultanée des deux faces de l'élément en feuille. La figure 2 représente la configuration générale d'une installation d'enduction selon l'invention.The embodiments which will now be described ensure the simultaneous coating of the two faces of the sheet element. FIG. 2 represents the general configuration of a coating installation according to the invention.

On sait qu'un dispositif d'enduction peut être utilisé:

  • - soit pour l'induction d'un élément en feuille préalablement fabriqué et, dans ce cas, il peut former une installation indépendante; cependant dans ce cas, il y aura bobinage et stockage intermédiaire de la feuille;
  • - soit directement pour l'enduction d'un élément en feuille en un poste déterminé d'une machine de fabrication dudit élément en feuille.
We know that a coating device can be used:
  • - either for the induction of a sheet element previously manufactured and, in this case, it can form an independent installation; however in this case, there will be winding and intermediate storage of the sheet;
  • - Either directly for coating a sheet element at a specific station of a machine for manufacturing said sheet element.

C'est ce dernier cas qui, à titre d'exemple, a été retenu dans la description qui suit. Ainsi, la figure 2 représente l'extrémité d'une machine à fabriquer le papier qui est équipée d'un dispositif selon l'invention.It is this latter case which, by way of example, has been retained in the description which follows. Thus, Figure 2 shows the end of a paper making machine which is equipped with a device according to the invention.

Entre deux groupes de cylindres sécheurs 22, 23 et 32, 33, de la sécherie d'une machine à papier classique, dont on n'a pas représenté la tête ni la fin de machine, la feuille 21 passe sur une série de rouleaux 25, 26, 27, 28 et 29 qui assurent à la fois sa tension et son déplacement selon un parcours déterminé.Between two groups of drying cylinders 22, 23 and 32, 33, from the dryer of a conventional paper machine, the head and end of which have not been shown, the sheet 21 passes over a series of rollers 25 , 26, 27, 28 and 29 which ensure both its tension and its movement along a determined route.

Entre les rouleaux 27 et 28, ladite feuille de papier circule verticalement et c'est à ce niveau qu'elle passe dans un dispositif d'enduction selon l'invention, indiqué de façon générale en 130, et qu'on décrira plus en détail par la suite.Between the rollers 27 and 28, said sheet of paper circulates vertically and it is at this level that it passes through a coating device according to the invention, indicated generally at 130, and which will be described in more detail. thereafter.

Dans le cas particulier représenté à la figure 2, les deux faces de la feuille sont enduites et, par conséquent, doivent éventuellement subir une opération de pré-séchage de la couche avant que la feuille n'entre en contact avec les cylindres 32 et 33, afin d'éviter que la couche encore fraîche n'adhère aux cylindres et soit de ce fait détériorée.In the particular case represented in FIG. 2, the two faces of the sheet are coated and, consequently, may have to undergo a pre-drying operation of the layer before the sheet comes into contact with the cylinders 32 and 33. , in order to prevent the still fresh layer from adhering to the cylinders and thereby being deteriorated.

On a représenté en 340 un premier élément de pré-séchage pour la face de la feuille destinée à entrer en contact avec le rouleau 28 et en 350 un second élément de pré-séchage pour l'autre face de la feuille.There is shown in 340 a first pre-drying element for the face of the sheet intended to come into contact with the roller 28 and in 350 a second pre-drying element for the other face of the sheet.

Naturellement, on comprendra que, comme dans le cas de la figure 1, le dispositif selon l'invention pourrait ne procéder à l'enduction que d'une seule des faces de la feuille et, dans ce cas, on pourrait ne prévoir qu'un seul système de séchage.Naturally, it will be understood that, as in the case of FIG. 1, the device according to the invention could only carry out the coating of one of the faces of the sheet and, in this case, we could only provide only one drying system.

L'élément en feuille 21 circule, dans le cas de la figure 2, verticalement de bas en haut.The sheet element 21 circulates, in the case of Figure 2, vertically from bottom to top.

Le dispositif d'enduction 130 pourra être constitué par l'une des variantes de réalisation qu'on décrira à présent.The coating device 130 could consist of one of the variant embodiments which will now be described.

A la figure 3, on a réalisé le dispositif d'enduction à l'aide de deux ensembles de caisse 30 et 30a similaires à la caisse de la figure 1 et disposés de part et d'autre d'une feuille de papier 21 se déplaçant à peu près verticalement de bas en haut. Dans l'exemple représenté, les deux ensembles de caisse 30 et 30a sont indentiques et symétriques par rapport au plan de la feuille 21. On se contentera donc d'en décrire en seul. Comme dans le cas de la figure 1, la caisse 34 comporte une chambre interne 35 dans laquelle circule la composition de couchage alimentée sous pression. Une fente 37 inclinée (servant d'injecteur) est pratiquée dans la caisse et contre la paroi de la fente la plus éloignée de la feuille 21 est fixée une extrémité d'une lame souple 38 élastiquement déformable. Un support 40a fixé sur la caisse 34 supporte sur toute sa longueur un tube 40 rempli par un fluide sous pression (la pression étant réglable).In FIG. 3, the coating device has been produced using two crate assemblies 30 and 30a similar to the crate in FIG. 1 and arranged on either side of a sheet of paper 21 moving roughly vertically from bottom to top. In the example shown, the two body assemblies 30 and 30a are identical and symmetrical with respect to the plane of the sheet 21. It will therefore be sufficient to describe them alone. As in the case of FIG. 1, the box 34 has an internal chamber 35 in which the coating composition supplied under pressure circulates. An inclined slot 37 (serving as an injector) is made in the box and against the wall of the most distant slot of the sheet 21 is fixed one end of a flexible blade 38 elastically deformable. A support 40a fixed on the body 34 supports over its entire length a tube 40 filled with a pressurized fluid (the pressure being adjustable).

En position de fonctionnement représentée à la figure 3, les deux lames 38 sont appliquées de part et d'autre de la feuille 21, leurs extrémités libres étant exactement en opposition et formant une zone de contact avec la feuille qui est parallèle à celle-ci afin de réaliser l'étalement et le lissage de la couche. Les lames sont maintenues sous tension l'une contre l'autre et elles présentent donc une courbure dont la convexité est dirigée vers la feuille 21, les lames s'écartant de la feuille à partir de leur extrémité libre en ménageant avec celle-ci un coin 41. L'axe de la fente, matérialisé par la flèche 42 (qui matérialise également le trajet de la veine de composition de couchage injectée dans le coin 41 est orienté sensiblement vers la zone de lissage fournie par les extrémités libres des lames. La veine de la composition atteint donc la feuille immédiatement en amont de ladite zone de lissage. L'éventuel excès de matière M projetée ruisselle le long des faces internes des caisses 34 sans être en contact avec la feuille en raison de l'écartement "g" entre ladite feuille et la face interne de la caisse. Cet excès M est récupéré dans un bac 13 et éventuellement renvoyé dans la chambre interne de la caisse, par l'intermédiaire du circuit d'alimentation, non représenté, de la caisse.In the operating position shown in FIG. 3, the two blades 38 are applied on either side of the sheet 21, their free ends being exactly in opposition and forming a zone of contact with the sheet which is parallel to the latter. in order to achieve spreading and smoothing of the layer. The blades are kept under tension one against the other and they therefore have a curvature whose convexity is directed towards the sheet 21, the blades moving away from the sheet from their free end by providing therewith a corner 41. The axis of the slot, materialized by the arrow 42 (which also materializes the path of the vein of coating composition injected into the corner 41 is oriented substantially towards the smoothing zone provided by the free ends of the blades. vein of the composition therefore reaches the sheet immediately upstream of said smoothing zone. The possible excess of material M projected flows along the internal faces of the boxes 34 without being in contact with the sheet due to the spacing "g" between said sheet and the internal face of the box This excess M is recovered in a tank 13 and optionally returned to the internal chamber of the box, via the supply circuit, not shown, of the box.

A la figure 4, on a représenté schématiquement une autre forme de réalisation dans laquelle on utilise deux lames 50 et 51 rigides et symétriques dont seule la lame 50 sera donc décrite. Cette lame rigide présente une courbure générale tournée vers la feuille 21 et est percée d'un canal médian 52 pour l'admission de la composition d'enduction jusqu'à la feuille. Le canal 52 communique d'une part avec une source de composition sous pression non représentée et débouche, d'autre part, en 53 sur l'extrémité libre de la lame, cette extrémité libre présentant une zone 54 plane et parallèle à la feuille 21 qui a pour rôle de réaliser l'étalement et le lissage de la couche. Les lames pourront être articulées à leurs extrémités inférieures montées sur un support fixe (non représenté) afin de permettre le réglage de l'épaisseur de la couche à déposer.In Figure 4, there is shown schematically another embodiment in which two blades 50 and 51 are used which are rigid and symmetrical of which only the blade 50 will therefore be described. This rigid blade has a general curvature turned towards the sheet 21 and is pierced with a median channel 52 for admitting the coating composition to the sheet. The channel 52 communicates on the one hand with a source of composition under pressure not shown and opens, on the other hand, at 53 on the free end of the blade, this free end having a flat area 54 and parallel to the sheet 21 which is responsible for spreading and smoothing the layer. The blades can be articulated at their lower ends mounted on a fixed support (not shown) to allow adjustment of the thickness of the layer to be deposited.

Pour leur application contre la feuille 21, on pourra prévoir tout système de mise sous tension des lames et par exemple des tubes pneumatiques tels que ceux qui sont représentés en traits interrompus en 55, ces tubes étant de même type que ceux des figures 1 et 3.For their application against the sheet 21, provision may be made for any system for tensioning the blades and for example pneumatic tubes such as those which are shown in broken lines at 55, these tubes being of the same type as those of FIGS. 1 and 3 .

L'exemple représenté à la figure 4 est le cas idéal où l'injection de la composition d'enduction et le lissage se produisent simultanément et au même endroit.The example shown in FIG. 4 is the ideal case where the injection of the coating composition and the smoothing take place simultaneously and in the same place.

Toutefois, cette solution peut être difficile à réaliser industriellement.However, this solution can be difficult to carry out industrially.

Dans la variante de réalisation de la figure 5, le dispositif d'enduction et de lissage est constitué de deux paires de lames 60 disposées symétriquement par rapport à la feuille verticale 21 et on en décrira donc une seule. Les deux lames 61 et 62 de chaque paire de lames sont souples et élastiquement déformables. Elles sont par ailleurs fixées par leur extrémité inférieure dans un support de lames 63 par des vis 64 permettant leur amovibilité. Comme on le voit à la figure 5, les supports 63 sont écartés de part et d'autre de la feuille 21. Par ailleurs, dans le support, les deux lames sont écartées l'une de l'autre par un caisson creux 65 qui sert à l'admission sous pression de la composition d'enduction dans le sens de la flèche; le caisson est relié à une source de composition (non représentée). En raison de ce montage, les deux lames 61 et 62 sont superposées et sensiblement parallèles. En position de fonctionnement représenté à la figure 5, les deux lames 61 sont appliquées l'une contre l'autre, sous tension, de chaque côté de la feuille 21 et il en est de même des deux lames 62. La tension des lames résulte de la position des supports 63. Entre les lames 61 et 62 se trouve ménagé un passage injecteur 66 permettant d'injecter la composition d'enduction entre les extrémités libres 67 et 68 des lames sur la feuille 21. On notera qu'au moins les extrémités libres 67 des lames aval 61 (dans le sens du défilement de la feuille 21 ) sont appliquées sur la feuille de façon à être planes et parallèles à la feuille. La planéité de ces extrémités est éventuellement maintenue par un tube pneumatique 69 (représenté en trait interrompu) identique aux tubes des figures 1 à 4.In the alternative embodiment of FIG. 5, the coating and smoothing device consists of two pairs of blades 60 arranged symmetrically with respect to the vertical sheet 21 and therefore only one will be described. The two blades 61 and 62 of each pair of blades are flexible and elastically deformable. They are also fixed by their lower end in a blade support 63 by screws 64 allowing their removable. As seen in Figure 5, the supports 63 are spaced on either side of the sheet 21. Furthermore, in the support, the two blades are spaced from one another by a hollow box 65 which is used for the admission under pressure of the coating composition in the direction of the arrow; the box is connected to a composition source (not shown). Due to this arrangement, the two blades 61 and 62 are superimposed and sensitive parallel. In the operating position shown in FIG. 5, the two blades 61 are applied one against the other, under tension, on each side of the sheet 21 and the same is true of the two blades 62. The tension of the blades results of the position of the supports 63. Between the blades 61 and 62 is provided an injector passage 66 making it possible to inject the coating composition between the free ends 67 and 68 of the blades on the sheet 21. It will be noted that at least the free ends 67 of the downstream blades 61 (in the direction of travel of the sheet 21) are applied to the sheet so as to be plane and parallel to the sheet. The flatness of these ends is optionally maintained by a pneumatic tube 69 (shown in broken lines) identical to the tubes of FIGS. 1 to 4.

La forme de réalisation de la figure 6 est celle qui semble convenir particulièrement pour une utilisation industrielle. Une structure fixe (non représentée) est équipée de deux barres 70 sensiblement horizontales, écartées et entre lesquelles défile verticalement un élément en feuille 21 destiné à recevoir une composition d'enduction. Le dispositif d'enduction est constitué, comme précédemment de deux ensembles symétriques par rapport à la feuille et dont un seul sera donc décrit.The embodiment of Figure 6 is that which appears to be particularly suitable for industrial use. A fixed structure (not shown) is equipped with two substantially horizontal bars 70, spaced apart and between which a sheet element 21 which is intended to receive a coating composition passes vertically. The coating device consists, as before, of two sets symmetrical with respect to the sheet and of which only one will therefore be described.

Sur la barre 70 est montée une structure-support 71 susceptible de basculer et d'être immobilisée autour de la barre sous l'action d'un mécanisme de réglage de position (non représenté). La structure-support 71 présente une glissière 72 dans laquelle est engagé un porte-lame 73 qui peut être bloqué dans la glissière par tout moyen approprié. L'extrémité inférieure 74 d'une lame 75 est fixée de façon amovible dans le support par exemple par des vis 76 afin de permettre un éventuel remplacement de la lame.On the bar 70 is mounted a support structure 71 capable of tilting and being immobilized around the bar under the action of a position adjustment mechanism (not shown). The support structure 71 has a slide 72 in which a blade holder 73 is engaged which can be locked in the slide by any suitable means. The lower end 74 of a blade 75 is removably fixed in the support, for example by screws 76 in order to allow possible replacement of the blade.

La lame 75 est souple et élastiquement déformable et lorsque les deux structures 71 sont dans la position représentée à la figure 6, les extrémités libres 77 des lames sont appliquées sur la feuille 21. Les lames sont maintenues dans cette position sous tension et elles présentent donc une courbure à convexité tournée vers la feuille 21.The blade 75 is flexible and elastically deformable and when the two structures 71 are in the position shown in FIG. 6, the free ends 77 of the blades are applied to the sheet 21. The blades are kept in this position under tension and therefore have a curvature with convexity turned towards the sheet 21.

On notera que les porte-lames 73 sont écartés de la feuille 21 d'une distance qui peut être réglée grâce à la structure 71, ce qui permet de modifier la force appliquant la lame sur la feuille et par voie de conséquence, l'épaisseur de la couche.It will be noted that the blade holders 73 are spaced from the sheet 21 by a distance which can be adjusted by means of the structure 71, which makes it possible to modify the force applying the blade to the sheet and consequently, the thickness of the diaper.

De préférence, l'extrémité libre 77 de chaque lame est associée à un tube pneumatique 78 contenant un fluide sous pression (dont la pression peut être réglée) et exerçant sur l'extrémité de la lame une pression dont la direction est sensiblement perpendiculaire à la feuille, cette pression assurant la planéité de l'extrémité de la lame et son parallélisme avec la feuille. Chaque tube pneumatique peut être porté sur toute sa lonqueur par exemple par un support dont les bras 79 (représentés en trait interrompu) sont fixés au porte-lame correspondant. Un injecteur 80 de composition de couchage constitué par un caisson creux allongé et ouvert en 81 pour constituer un bec d'injection est suspendu à la structure 71, entre la feuille 21 et chacune des lames 75.Preferably, the free end 77 of each blade is associated with a pneumatic tube 78 containing a pressurized fluid (the pressure of which can be adjusted) and exerting on the end of the blade a pressure whose direction is substantially perpendicular to the sheet, this pressure ensuring the flatness of the end of the blade and its parallelism with the sheet. Each pneumatic tube can be carried over its entire length, for example by a support whose arms 79 (shown in broken lines) are fixed to the corresponding blade holder. An injector 80 of coating composition constituted by an elongated hollow box and open at 81 to constitute an injection nozzle is suspended from the structure 71, between the sheet 21 and each of the blades 75.

La suspension du caisson est constituée par des tiges 88 dont une extrémité 82 est engagée de façon réglable dans la structure 71 tandis que l'autre extrémité 83 constitue un palier pour un axe 84 solidaire du caisson 80. Le caisson est relié à sa partie inférieure, par une tuyauterie 85, à une source de composition de couchage équipée d'un système d'alimentation sous pression du caisson (non représenté).The suspension of the box is constituted by rods 88, one end 82 of which is adjustably engaged in the structure 71 while the other end 83 constitutes a bearing for an axis 84 integral with the box 80. The box is connected to its lower part , via a pipe 85, to a source of coating composition equipped with a pressurized supply system for the box (not shown).

On notera que la position du caisson est réglable par rapport à la structure par pivotement autour des axes de suspension 84 et qu'une fois le caisson placé dans une position convenable, il peut être bloqué dans cette position par tout système de verrouillage (non représenté) approprié. Comme on le voit à la figure 6, le bec d'injection 81 du caisson est situé le plus près possible de la zone de lissage réservée entre les extrémités 77 des lames. En cours de fonctionnement, la composition est injectée directement dans le coin formé entre chacune des lames et la feuille 21 et le bec d'injection est noyé dans le produit. L'éventuel excès de produit est évacué de la zone d'injection par ruissellement sur la face 86 du caisson en regard de la feuille 21, cette face s'écartant progressivement de la feuille.Note that the position of the box is adjustable relative to the structure by pivoting around the suspension axes 84 and that once the box placed in a suitable position, it can be locked in this position by any locking system (not shown ) appropriate. As seen in Figure 6, the injection nozzle 81 of the box is located as close as possible to the smoothing area reserved between the ends 77 of the blades. During operation, the composition is injected directly into the corner formed between each of the blades and the sheet 21 and the injection nozzle is embedded in the product. The possible excess of product is evacuated from the injection zone by trickling onto the face 86 of the box opposite the sheet 21, this face progressively moving away from the sheet.

L'excès est recueilli ensuite dans un bac 87.The excess is then collected in a tank 87.

La position optimale des éléments constituant le dispositif sera précisée en référence au schéma de la figure 7.The optimal position of the elements constituting the device will be specified with reference to the diagram in FIG. 7.

En effet, comme on l'a vu précédemment, la distance entre le bec de l'injecteur et la zone de lissage doit être la plus faible possible.In fact, as we have seen previously, the distance between the nozzle of the injector and the smoothing zone must be as small as possible.

Cette distance dépend:

  • - de l'épaisseur du bec de l'injecteur,
  • - de la courbure des lames qui est fonction de la géométrie adoptée pour chaque application.
This distance depends on:
  • - the thickness of the nozzle of the injector,
  • - the curvature of the blades which is a function of the geometry adopted for each application.

Sur le schéma de la figure 7, on a indiqué:

  • - en "e" l'épaisseur du bec de l'injecteur,
  • - en "d" la distance optimale entre le bec de l'injecteur et l'arête du bord libre des lames,
  • - en "a" l'angle apparent en bout de lame.
On the diagram of figure 7, one indicated:
  • - in "e" the thickness of the nozzle of the injector,
  • - in "d" the optimal distance between the nozzle of the injector and the edge of the free edge of the blades,
  • - at "a" the apparent angle at the end of the blade.

Par ailleurs, on conviendra que la lettre grecque ε représente l'espace nécessaire au passage de la feuille sans frottement et au retour de la composition de couchage, ainsi que l'intervalle éventuel entre lame et injecteur.Furthermore, it should be understood that the Greek letter ε represents the space necessary for the passage of the sheet without friction and for the return of the coating composition, as well as the possible interval between blade and injector.

Le calcul et l'expérimentation montrent que la position optimale de l'injecteur se situe à une distance "d" telle que:

Figure imgb0001
soit
Figure imgb0002
ε est compris en général entre 0 et 10 mm, espacement considéré comme normal pour le passage d'une feuille sur une machine à papier industrielle.Calculation and experimentation show that the optimal position of the injector is located at a distance "d" such that:
Figure imgb0001
is
Figure imgb0002
ε is generally between 0 and 10 mm, spacing considered normal for the passage of a sheet on an industrial paper machine.

Dans la pratique, on choisira pour "d" une distance inférieure à la longueur de la lame utilisée.In practice, a distance less than the length of the blade used will be chosen for "d".

On donnera ci-après quelques exemples con- crêts:

  • a/ avec un injecteur de 5 mm d'épaisseur au bec (ε=5 mm), placé à 2 mm du papier et à 1 mm de la lame (E=3 mm) et une lame faisant un angle a de 12°8 (cotga=4,4), la distance optimale de l'injecteur sera:
    • d=[5+(2+1)]x4,4=35,2 mm
  • b/ Si, dans la même configuration, on désire placer l'injecteur à 5 mm du papier, on aura:
    • d=[5+(5+1)[×4,4=48,4 mm
  • c/ Si on dispose d'un injecteur de 10 mm d'épaisseur, situé à 10 mm du papier, on aura:
    • d=[10+(10+1)]×4,4=92,4 mm
Some concrete examples are given below:
  • a / with an injector 5 mm thick at the nozzle (ε = 5 mm), placed 2 mm from the paper and 1 mm from the blade ( E = 3 mm) and a blade making an angle a of 12 ° 8 (cotga = 4.4), the optimal distance from the injector will be:
    • d = [5+ (2 + 1)] x4.4 = 35.2 mm
  • b / If, in the same configuration, we want to place the injector 5 mm from the paper, we will have:
    • d = [5+ (5 + 1) [× 4.4 = 48.4 mm
  • c / If we have an injector 10 mm thick, located 10 mm from the paper, we will have:
    • d = [10+ (10 + 1)] × 4.4 = 92.4 mm

Par ailleurs, il faut noter que le dispositif selon l'invention permet de réaliser aussi bien des enductions symétriques comme aux figures 3 à 6 que dissymétriques comme aux figures 8 et 9.Furthermore, it should be noted that the device according to the invention makes it possible to produce both symmetrical coatings as in FIGS. 3 to 6 as well as asymmetrical coatings as in FIGS. 8 and 9.

La dissymétrie du dépôt des couches sur les deux faces de l'élément en feuille peut être recherchée:

  • - soit pour obtenir volontairement un papier couché de caractéristiques différentes sur les deux faces;
  • - soit, au contraire, pour corriger les caractéristiques existantes d'une des faces de façon à obtenir un papier identique sur les deux faces.
The asymmetry of the deposition of the layers on the two faces of the sheet element can be sought:
  • - either to voluntarily obtain a coated paper with different characteristics on both sides;
  • - Or, on the contrary, to correct the existing characteristics of one of the faces so as to obtain identical paper on the two sides.

Les expériences pratiques réalisées à ce jour montrent qu'avec le dispositif selon l'invention la dissymétrie peut être obtenue au moins de deux façons, comme le montrent les figures 8 et 9, à savoir:

  • - soit par déplacement de l'axe des lames, c'est-à-dire en décalant simultanément dans un plan horizontal les deux chambres pneumatiques (figure 8);
  • - soit par abaissement d'une des deux chambres pneumatiques (figure 9).
The practical experiments carried out to date show that, with the device according to the invention, the asymmetry can be obtained in at least two ways, as shown in FIGS. 8 and 9, namely:
  • - Either by displacement of the axis of the blades, that is to say by simultaneously shifting in a horizontal plane the two pneumatic chambers (Figure 8);
  • - either by lowering one of the two pneumatic chambers (Figure 9).

A la figure 8, on a représenté en trait plein le dispositif selon l'invention dans lequel, comme aux figures précédentes, les lames I1 et I2 sont symétriques par rapport à l'élément en feuille S. En agissant sur le support de lames, on peut déplacer l'axe de celles-ci et les faire venir dans la position dissymétrique représentée en trait interrompu en L1 et LZ; alors que dans le cas de la symétrie, les lames font un même angle a par rapport à l'élément S, dans le cas de la dissymétrie, la lame L1 forme un angle y et la lame Lz un angle β avec l'élément S. β est plus petit que y. La lame Lz et plus lissante.In Figure 8, there is shown in solid lines the device according to the invention in which, as in the previous figures, the blades I 1 and I 2 are symmetrical with respect to the sheet element S. By acting on the support of blades, one can move the axis of these and bring them into the asymmetrical position shown in broken lines in L 1 and L Z ; whereas in the case of symmetry, the blades make the same angle a with respect to the element S, in the case of asymmetry, the blade L 1 forms an angle y and the blade L z an angle β with the element S. β is smaller than y. The L z blade is smoother.

A la figure 9, on a représenté en trait plein les lames 14 et 13 dans leur position symétrique (même angle a) par rapport à l'élément S. En abaissant le tube pneumatique verticalement d'une distance "ab" de sa position initiale représentée en trait interrompu en C4 dans la position en trait plein C'4, on provoque un déplacement consécutif de la lame 14 vers sa position en trait interrompu L4, la lame faisant alors avec l'élément S un angle β inférieur à α.In Figure 9, there is shown in solid lines the blades 1 4 and 1 3 in their symmetrical position (same angle a) relative to the element S. By lowering the pneumatic tube vertically by a distance "ab" from its initial position shown in broken lines at C 4 in the solid line position C ' 4 , the blade 1 4 is moved consecutively to its broken line position L 4 , the blade then making an angle β with the element S less than α.

Ces déplacements de chambres pneumatiques provoquent une augmentation du dépôt de couche du côté où la lame devient plus lissante, c'est-à-dire du côté de la lame Lz à la figure 8 et du côté de la lame L4 à la figure 9.These displacements of pneumatic chambers cause an increase in layer deposition on the side where the blade becomes smoother, that is to say on the side of the blade L z in FIG. 8 and on the side of the blade L 4 in FIG. 9.

Ces différentes positions des chambres pneumatiques ont permis de créer des dissymétries relativement importantes (par exemple, dépôt d'une couche de 8 g/m2 sur une face, et de 14 g/m2 sur l'autre).These different positions of the pneumatic chambers made it possible to create relatively large asymmetries (for example, deposition of a layer of 8 g / m 2 on one side, and of 14 g / m 2 on the other).

Dans le cas où l'organe de pression n'est pas une chambre pneumatique, mais, par exemple, une contre-lame (figures 10 à 13), on obtiendra évidemment les mêmes dissymétries en déplaçant dans les mêmes conditions les positions des lignes d'appui des contre-lames sur les lames de lissage.In the case where the pressure member is not a pneumatic chamber, but, for example, a counter blade (FIGS. 10 to 13), the same asymmetries will obviously be obtained by moving the positions of the lines d under the same conditions. support of the counter blades on the smoothing blades.

Ces réglages peuvent s'effectuer de façon continue, en cours de couchage, sans changer la composition des couches et sans autres modifications du dispositif.These adjustments can be made continuously, during coating, without changing the composition of the layers and without other modifications to the device.

Il existe évidemment d'autres moyens de créer de telles dissymétries, comme, par exemple

  • - le choix d'une lame plus épaisse donc plus rigide sur une face (dans ce cas, le dépôt diminue par rapport à une lame souple);
  • - la modification de la formule de couchage sur une des deux faces. Toutefois, il semble que ces deux derniers moyens soient difficilement applicables pour le couchage en continu.
There are obviously other ways to create such asymmetries, such as, for example
  • - the choice of a thicker blade therefore more rigid on one side (in this case, the deposit decreases compared to a flexible blade);
  • - the modification of the coating formula on one of the two faces. However, it seems that these last two means are difficult to apply for continuous coating.

Les figures 10 à 13 représentent un moyen avantageux permettant d'exercer une pression sur la lame de lissage, sur la zone de contact entre cette lame de lissage et le papier. Dans ces formes de réalisation, l'organe de pression est constitué par une contre-lame élastique située à l'extérieur de la lame de lissage, et dont l'extrémité libre est maintenue appliquée élastiquement sur la lame de lissage au point de contact entre ladite lame de lissage et l'élément en feuille. L'extrémité opposée est ancrée dans un support mobile de sorte que, lors de sa mise sous tension, la contre-lame présente une courbure à convexité tournée vers l'élément en feuille. Cette contre-lame peut être réalisée en tout matériau souple approprié: métal, plastique, etc.Figures 10 to 13 show an advantageous means for exerting pressure on the smoothing blade, on the contact zone between this smoothing blade and the paper. In these embodiments, the pressing member is constituted by an elastic counterblade situated outside the smoothing blade, and the free end of which is kept applied elastically on the smoothing blade at the point of contact between said smoothing blade and the sheet element. The opposite end is anchored in a movable support so that, when it is tensioned, the counter blade has a curvature with convexity turned towards the sheet element. This counter blade can be made of any suitable flexible material: metal, plastic, etc.

La contre-lame peut être disposée soit dans dans le même sens que la lame de lissage correspondante, soit en sens opposé, les points d'ancrage respectifs de la lame de lissage et de la contre-lame étant, dans ce dernier cas, situés de part et d'autre de la zone de contact entre ces deux éléments.The counter blade can be arranged either in the same direction as the corresponding smoothing blade, or in opposite direction, the respective anchoring points of the smoothing blade and the counter blade being, in the latter case, located on either side of the contact area between these two elements.

Pour la commodité de la description, on se bornera à décrire ci-après dés formes de réalisation dans lesquelles lame de lissage et contre-lame sont disposées dans le même sens.For the convenience of the description, we will limit ourselves to describing below embodiments in which the smoothing blade and counter blade are arranged in the same direction.

Sur la figure 10, une bande de papier 1 défile de bas en haut, dans le sens de la flèche, dans une machine appropriée. Deux lames de lissage 75, 75' maintenues par des supports 73, 73' exercent sur les deux faces de la bande de papier, en un point 91, une pression pour lisser sur chacune des deux faces une couche d'une composition d'enduction. La composition d'enduction est amenée entre la bande de papier et la lame 75, au moyen d'un appareil non représenté tel que ceux décrits dans les exemples précédents. On assure la planéité de l'extrémité libre de la lame 75, 75' (zone de lissage) au moyen d'une contre-lame 83, 83'. De préférence, les lames 83, 83' sont plus courtes que les lames 75, 75' qui sont avantageusement très souples, ce qui assure en outre un effet de lissage plus uniforme sur la largeur de la feuille.In FIG. 10, a strip of paper 1 runs from bottom to top, in the direction of the arrow, in a suitable machine. Two smoothing blades 75, 75 'held by supports 73, 73' exert on both sides of the paper strip, at a point 91, a pressure to smooth on each of the two faces a layer of a coating composition . The coating composition is brought between the paper strip and the blade 75, by means of a device not shown such as those described in the previous examples. The flatness of the free end of the blade 75, 75 ′ (smoothing area) is ensured by means of a counter blade 83, 83 ′. Preferably, the blades 83, 83 'are shorter than the blades 75, 75' which are advantageously very flexible, which also provides a more uniform smoothing effect over the width of the sheet.

Chaque contre-lame 83 est ancrée dans un support 84. Grâce à des moyens classiques simples non représentés, les supports 84 peuvent être tournés sur eux-mêmes, et déplacés verticalement (y'y) et horizontalement (x'x). Il est ainsi possible de régler la force de pression, en modifiant la courbure de la contre-lame, tout en plaçant le bord libre de la contre-lame au voisinage du bord libre de la lame de lissage.Each counter blade 83 is anchored in a support 84. Thanks to simple conventional means not shown, the supports 84 can be turned on themselves, and moved vertically (y'y) and horizontally (x'x). It is thus possible to adjust the pressure force, by modifying the curvature of the counter blade, while placing the free edge of the counter blade in the vicinity of the free edge of the smoothing blade.

Sur la figure 11, le dispositif comporte les mêmes éléments que sur la figure 10 et en outre des moyens auxiliaires sous forme de tubes pneumatiques 78, 78', qui peuvent être placés en tout point de la contre-lame, vers le milieu, ou vers le bord libre. On peut alors régler en plus la pression du fluide à l'intérieur du tube pneumatique et la position de ce tube sur la contre-lame.In FIG. 11, the device comprises the same elements as in FIG. 10 and in addition auxiliary means in the form of pneumatic tubes 78, 78 ′, which can be placed at any point of the counter blade, towards the middle, or towards the free edge. We can then adjust in addition the fluid pressure inside the pneumatic tube and the position of this tube on the counter blade.

Le dispositif des figures 12 et 13 comporte tous les éléments du dispositif de la figure 10, et en outre un système de pression constitué par une série de segments ou doigts 85, disposés selon la largeur de la feuille, et qui peuvent être placés de manière à agir sur la contre-lame en tout point situé entre l'extrémité libre de ladite contre-lame et son point d'ancrage. Selon l'invention, ces doigts sont réglables. Ils peuvent être réglés un par un, ou ensemble, manuellement ou automatiquement, par exemple commandés par un dispositif relié à un capteur qui détecte les irrégularités de la couche sur la largeur de la feuille, de façon à modifier la pression exercée par un ou plusieurs doigts, en fonction de la correction à apporter aux défauts détectés à leur niveau.The device of FIGS. 12 and 13 comprises all the elements of the device of FIG. 10, and in addition a pressure system constituted by a series of segments or fingers 85, arranged along the width of the sheet, and which can be placed so to act on the counter blade at any point situated between the free end of said counter blade and its anchor point. According to the invention, these fingers are adjustable. They can be adjusted one by one, or together, manually or automatically, for example controlled by a device connected to a sensor which detects irregularities in the layer across the width of the sheet, so as to modify the pressure exerted by one or more fingers, depending on the correction to be made to faults detected at their level.

On peut ainsi régler ponctuellement la pression exercée sur la largeur de la lame de lissage en fonction des conditions particulières d'enduction (irrégularité du support ou du dépôt de couche sur la laize par exemple). On peut également pallier une déformation accidentelle localisée de la lame de lissage sans avoir à changer immédiatement ladite lame.It is thus possible to adjust the pressure exerted on the width of the smoothing blade from time to time as a function of the particular coating conditions (irregularity of the support or layer deposition on the width for example). It is also possible to compensate for a localized accidental deformation of the smoothing blade without having to immediately change said blade.

Les doigts peuvent être montés dans un support 86, qui peut comporter tout les éléments permettant la commande automatique ou manuelle.The fingers can be mounted in a support 86, which can include all the elements allowing automatic or manual control.

Les modes de réalisation de l'organe de pression décrits ci-dessus (figures 10 à 13) sont particulièrement aptes à l'obtention d'une bonne rectitude et d'une grande fiabilité de l'appui sur les lames de lissage. Ils permettent également, en exploitation industrielle, un ajustement aisé et précis de la ligne d'appui, celle-ci étant bien définie et facile à visualiser.The embodiments of the pressure member described above (Figures 10 to 13) are particularly suitable for obtaining good straightness and high reliability of the support on the smoothing blades. They also allow, in industrial operation, an easy and precise adjustment of the support line, the latter being well defined and easy to visualize.

Ils peuvent remplacer les tubes pneumatiques dans tous les exemples décrits plus haut (figures 1 à 9) dans le cas d'une enduction, aussi bien simple-face que double-face.They can replace the pneumatic tubes in all the examples described above (FIGS. 1 to 9) in the case of a coating, both single-sided and double-sided.

Claims (16)

1. Process for continuously coating a web (1, 21) consisting in:
- continuously moving said web (1) from bottom to top in a substantially vertical direction, between at least two means (38) located on each side of the web,
. at least one of the said means being formed by an spreading blade (38)
+ applied by one end against one side of the web to be coated,
+ the other end being spaced apart from bhe web and directed in regards to the first in an opposite direction to the running direction of the web,
. the other means acting as reaction element for the first,
- placing the coating composition into contact with the said surface to be coated,
. upstream of the zone of contact of the said spreading blade against the web,
- and exerting pressure,
. on the said spreading blade,
. in direction of the side to be coated to ensure spreading of the said coating composition on the side to be coated,

the said process being characterized by the fact that
- on one hand, the coating composition is directed as a stream (42),
. continuously directed towards the top of the angle (a) formed by the web (21) and the blade (38, 61, 75), by the lateral walls,
. and fed from a delivery means under pressure (35) of this composition,
- and on the other hand, the coating composition received from the means under pressure (35)
. a total mechanical energy, as such as the stream (42) is directed by the effect of the pressure towards the apex of the angle (a), into a translation movement continuously oriented in a direction progressively closed to the direction of the web (21).
2. Process according to claim 1, characterized by the fact that the said spreading blade (38) is submitted to a force which is:
- different from its own flexion force,
- applied on the back of the contact point between the blade and the web,
- and directed towards the side of the web to be coated.
3. Process according to any of claims 1 and 2, characterized by the fact that the delivery of the coating composition is achieved by use of an injector (52, 66)
- made by the convergence of the said lateral conducting walls (61, 62) of the stream.
- the outlet orifice of which being located in the vicinity of the contact zone (54) between the web and the smoothing blade, upstream of this zone in regards to the running direction of the web (21).
4. Process according to any claims 1 and 2, characterized by the fact that the depositing of the composition in contact with the face of the web to be coated is provided by using an injector (80) the outlet of which being located to a distance (d) from the free end of the blade (75) in contact with the web which is equal:
- to the sum
. of the thickness (e) of the injector,
. and of the clearances (E) between said injector (80) and the web (21) at one side, and the smoothing blade (75) at a second side,
- multiplied by the cotangent of the angle (a) formed by said smoothing blade and said web.
5. Device for continuously coating a web, namely a paper, cardboard, plastic sheet material or similar, with a coating composition, the said device comprising:
- a guiding and continuous running means from bottom to top of the web in a substantially vertical direction,
- a means for depositing said composition,
- and two means (8, 2, 38) between which runs the web (21),
. at least one being formed by a spreading blade,
+ applied by one end against one side of the web (21) to be coated,
+ the other end being spaced apart from the web and directed in regards to the first in an opposite direction of the running direction of the web,
+ and eventually provided with a pressure means (40, 40a) associated with the free end of the blade and applying on it a pressure in a direction substantially perpendicular to the web (21), in order that the said free end is substantially plane, as the other part of the blade has a curvature whose convexity is directed towards the web (21),

the said device being characterized by the fact that the means for depositing said composition comprises an outlet (81, 53) forming injector (80),
. located between the two ends of the blade (38) in the vicinity of this one which is in contact with the web (21),
. and directed towards the apex (a) formed by the web and the blade.
6. Device according to claim 5 for coating only one side of a web (1 ), characterized by the fact that the said spreading blade is fixed to a support (4) which further comprises:
- an internal closed space (5) for canalyzing the coating composition, whose convergency forms at least one orifice (7),
. adjacent to the end of the blade (8) fixed to the support,
. and communicating the said internal space with the area (11) located between the part of the blade external to the support and the part of the web (1) in front of the blade,
- means (6) provided in order to inject under pressure the coating composition in a stream movement out of the said internal space (5) of the support and into the said area (11).
7. Device according to claim 5. characterized by the fact that the spreading blade comprises at least one delivery channel (52) for the coating composition,
- bored into its 'thickness,
- and opened by a outlet (53) into the zone (54) of the blade in contact with the web (21), ), the said channel acting as injector, the said blade comprising, downstream of the outlet and in the running direction of the web, a plane portion (54) applied unto the web and smoothing the coating.
8. Device according to claim 5, characterized by the fact that the injector (66) is formed by a space between two flexible blades (61, 62) superposed, subjected to a tension and substantially parallel which are both. attached by one end to an holder (63) spaced apart from the web (21), whose free ends (67, 68) are applied against the web (21) by forming between them a space where the coating composition coming from the internal space between both blades is applied against the web (21), the blade located downstream in the running direction of the web, forming the smoothing blade of the device.
9. Device according to claim 5, characterized by the fact that the injector (80) of the coating composition is located in the angle (a) formed by the web and the smoothing blade, the outlet orifice of the said injector being posi- tionned at a distance (d) from the free edge of the spreading blade which is equal
- to the sum
. of the thickness (e) of the injector (80),
. and of the clearance (e) between the injector (80) and the web (21) at one hand, and the blade (75) at a second hand,
- multiplied by the cotangent of the apparent angle (a) formed by the blade and the web.
10. Device according to any claims 5 to 9, characterized by the fact that the pressure element on the spreading blade (38) comprises a flexible tube (40) filled in with a fluid under pressure.
11. Device according to any claims 5 to 9, characterized by the fact that the pressure element comprises a flexible counter-blade (83), different from the smoothing blade and located outside of the said smoothing blade (75) in regard to the web (1). the free end of which being exerting on the smoothing blade, near the contact zone between the blade and the web, a pressure consisting of the elastic flexion force of the counter-blade.
12. Device according to claim 1 1, characterized by the fact that the flexion of the counter-blade is provided by moving the fixing point of the said counter-blade (83) with respect to the web and/or by pivoting around the axis of the said fixing point.
13. Device according to claim 11, characterized by the fact that the flexion of the counter-blade is provided by a pneumatic tube (78) which exerts a pressure on the said counter-blade (83) in a point located between the fixing point and the free end of said counter blade (83).
14. Device according to claim 11, characterized by the fact that the flexion of the counter-blade is provided by a plurality of adjustable segments or fingers (85) posi- tionned in the width of the smoothing blade, the said fingers acting on the said counter-blade (83) following a line paralleJ to its free end and located between said free end and fixing point of said counter-blade.
15. Device according to claims 5 to 14, for simultaneous coating of both sides of a web, characterized by the fact that it comprises two identical assemblies (75, 75') positioned symetrically with respect to the web (1).
16. Device according to claims 5 to 14 for simultaneous coating of both sides of a web, characterized by the fact that it comprises two identical assemblies (L3, L4) located on each side of the web (S), the free ends of the smoothing blades being located at the same level with respect to the web, while the support lines of the pressure means being slightly displaced along the web and of one side with respect to the other, in order to achieve disymmetrical coating characteristics on respective sides of the web.
EP80400306A 1979-03-14 1980-03-06 Method of and apparatus for continuously coating sheet material, particularly a paper or cardboard web Expired EP0016681B1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
FR7906506A FR2451418A1 (en) 1979-03-14 1979-03-14 Web coating equipment for paper-making - has coating substance forced from tube under attached blade with pneumatic tube along tip
FR7906506 1979-03-14
FR8003392A FR2476165A2 (en) 1979-03-14 1980-02-15 METHOD AND DEVICE FOR CONTINUOUSLY COATING A SHEET ELEMENT, IN PARTICULAR A BAND OF PAPER OR CARDBOARD
FR8003392 1980-02-15

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EP0016681A1 EP0016681A1 (en) 1980-10-01
EP0016681B1 true EP0016681B1 (en) 1984-05-09

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FR2359650A1 (en) * 1976-07-30 1978-02-24 Centre Tech Ind Papier Coating paper webs - by application of a compsn. prior to passage through a nip formed between to flat elements resiliently biassed together

Also Published As

Publication number Publication date
US4331713A (en) 1982-05-25
FI64962B (en) 1983-10-31
FR2476165A2 (en) 1981-08-21
FI64962C (en) 1984-02-10
JPS55159871A (en) 1980-12-12
FI800701A (en) 1980-09-15
FR2476165B2 (en) 1983-11-10
ES8200426A1 (en) 1981-11-01
DE3067733D1 (en) 1984-06-14
CA1158110A (en) 1983-12-06
EP0016681A1 (en) 1980-10-01
ES489603A0 (en) 1981-11-01
BR8001407A (en) 1980-11-11

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