WO2008037850A1 - Procédé de fabrication de racle, racle et porte-racle - Google Patents

Procédé de fabrication de racle, racle et porte-racle Download PDF

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Publication number
WO2008037850A1
WO2008037850A1 PCT/FI2007/050513 FI2007050513W WO2008037850A1 WO 2008037850 A1 WO2008037850 A1 WO 2008037850A1 FI 2007050513 W FI2007050513 W FI 2007050513W WO 2008037850 A1 WO2008037850 A1 WO 2008037850A1
Authority
WO
WIPO (PCT)
Prior art keywords
doctor blade
blade
fiber
doctor
tip
Prior art date
Application number
PCT/FI2007/050513
Other languages
English (en)
Inventor
Mikko Karioja
Harri Ruotsalainen
Jukka Samppala
Denis Sitz
Heikki Toivanen
Original Assignee
Metso Paper, Inc.
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 FI20065601A external-priority patent/FI20065601L/fi
Priority claimed from FI20065602A external-priority patent/FI20065602L/fi
Application filed by Metso Paper, Inc. filed Critical Metso Paper, Inc.
Priority to DE200711002273 priority Critical patent/DE112007002273T8/de
Publication of WO2008037850A1 publication Critical patent/WO2008037850A1/fr

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
    • D21G3/00—Doctors
    • D21G3/005—Doctor knifes

Definitions

  • the present invention relates to a method of manufacturing a doctor blade, a doctor blade and a blade holder.
  • the blade concerned is meant to be installed in contact with a moving surface and the blade can be used either to clean the moving surface or to apply a medium on said surface.
  • the use of the blade and the blade holder of the invention is particularly advantageous in paper and board machines or corresponding web forming apparatus, in which the purpose is, by means of the blade, to keep either the rolls or the fabrics clean, to apply paste or corresponding medium onto the surface of the web, to detach the web from the surface of a roll or for example a Yankee cylinder or to crep the web.
  • the invention also relates to a new type of a doctor blade construction where one of the leading ideas has been, in addition to improving the usage properties of the doctor blade, also to manufacture the doctor blade using, when possible, less expensive materials than before.
  • Prior art blade holders are in most cases manufactured of a metal material.
  • the blade holder In a known blade holder used in a paper machine environment the blade holder includes an arm portion at which the blade holder is secured to a body formed by a bar. The arm portion continues in a jaw portion which includes a gap for a blade.
  • Composite materials have recently taken over space from conventional metal materials in different applications, where particular advantages are to be gained when using materials which are better suited for that application.
  • blade holders manufactured fully of a composite material have not been used for long.
  • a blade holder having a composite structure is light and durable compared with conventional metal blade holders. For example by orientating the reinforcing fibers, the blade holder adapts better to the surface. In spite of this the blade holder is stiff in the loading direction of the blade, in other words in the machine direction. Further, a composite structure reverts to its original form even from extensive deformations.
  • a treatment apparatus having a composite design comprising a body provided in the vicinity of a moving surface, a blade holder manufactured of a composite material essentially as one piece and connected to the body, a blade disposed in the blade holder, the edge of the blade being arranged to be placed in contact with the moving surface by moving the blade holder, and a separate pressing blade provided in the blade holder, one side of which is disposed to the blade holder while the other side extends closer to said edge than the blade holder.
  • the blades presently in use including the blades used in applying different pastes or corresponding media as well as doctor blades used for keeping rolls and fabrics clean, and creping blades, are more and more manufactured of composite materials so that in the blade there is a sharp edge at one long side.
  • one long side edge of the blade has been chamfered to a desired angle and this sharp edge is used for example to scrape a web or impurities from the surface of a roll or a cylinder.
  • This structure imposes both an ecological and an economic problem as only a small portion of the width of the blade is used and thus most of the blade material goes wasted.
  • US 4,549,933 discloses a doctor blade comprising a core layer of a fiber material, a graphite fiber layer disposed outside it and fiber material layers on the outer surfaces.
  • the doctor blade is similar along its whole machine direction width and in the direction of thickness essentially symmetric relative to the core layer.
  • US-B1 -6,416,843 discloses a doctor blade used to keep roll surfaces clean, formed all over of a laminated fiber material layers at least one of which is a carbon fiber layer which contains also grinding particle for treating the roll surface. Like the doctor blade according to the previous publication, also this doctor blade is along its entire width made of the same material and essentially symmetric in the thickness direction.
  • US-B1 -6,565,712 discussed a doctor blade having a composite design having a core of long fibers other than glass fiber material, an intermediate layer, in which at least one layer is of carbon fiber material, and a surface layer which is described to be composed of one or several layers preferably of a carbon fiber material. Also this doctor blade is both homogenous along its entire width and symmetric in the thickness direction.
  • thermosetting plastic blade of mere carbon fiber, or glass fiber and carbon fiber is less than 0,5 mm/h.
  • the reinforcing material of which is a glass fiber - carbon fiber hybrid because solid carbon fiber blades do not start to wear and the scraping properties (heat resistance, stiffness, high friction, sharpness) of purely glass fiber- reinforced blades are not sufficient.
  • Thermosetting plastic blades having glass fiber - carbon fiber reinforcement designs have been manufactured and designed to be similar on both sides of the center line of the blade structure (for example WO 03/060231), resulting in the symmetry of the blade in the thickness direction.
  • Prior art also discloses doctor blades used in paper and board machines for scraping belts, in particular conveyor belts, in wet pressing, drying, calendering and coating to keep the belts clean (FI-U-20010246).
  • These belts are relatively soft and thus liable to be damaged, especially when scraping them with a metal doctor blade.
  • a roll coated with a soft material The same risk exists with a roll coated with a soft material. Therefore various plastics are usually used instead of metal in the manufacture of doctor blades.
  • Some plastics, in particular prior art fiber-reinforced plastics have been found to be too hard for scraping belts and thus, in order to avoid damages and to minimize wearing, softer materials must be used than the known fiber-reinforced plastics.
  • the tip of a blade made of this kind of a material is swaged when it hits a potential boss in the belt or a transverse groove and thus does not damage the belt.
  • the doctor blades used in scraping rolls are too hard and thus they are not applicable in the scraping of soft belts.
  • the publication FI-U-20010246 mentioned describes an arrangement in a paper or a board machine for scraping a belt or a soft roll coating with a doctor blade having two or at best three functional components which together form the doctor blade.
  • the doctor blade described in the publication for scraping a belt or a soft roll coating is at least partly manufactured of a material, the hardness of which is essentially the same as or lower than the hardness of the surface to be scraped. Thus, the doctor blade is prevented from cutting into the surface.
  • the material described above, which does not damage the surface has been provided as a layer extending along the entire width of the doctor blade.
  • the thickness of the layers is uniformly at least one half of the thickness of the doctor blade; thus, an adequate abrasion resistance is obtained.
  • a support structure has been provided in the layer which together with the layer forms the doctor blade. The supporting structure has been disposed in the doctor so that even when scraping with a worn doctor blade the belt always contacts the wearing layer of the doctor first, and the layer rather swages in stead of cutting into the belt.
  • the material which does not damage the surface is for example high-density polyethylene (HDPE), polyurethane (PU), polytetrafluoroethylene (PTFE), which are soft and their friction coefficient is low.
  • the Fl publication in question discloses also a doctor blade in which the top surface of the layer mentioned is provided with a further thin layer made of a harder material than the layer mentioned which extends to the contact point of the doctor blade and the belt as the first one of the different layers of the doctor.
  • the additional layer is made of a harder material than the layer under it, the doctor blade stays sharp at all times.
  • the additional layer although it is hard, is designed to become swaged like a soft layer and thus it does not damage the belt. It is described that the additional layer is either a separate structure or even a coating. It is described to be characteristic of the additional layer that it is adequately thin so that it does not prevent the layer from being swaged.
  • the laminate accepted to be used as the doctor material is mainly manufactured of thermosetting plastics, which has the majority of the market. Also thermoplastic materials are available already, which enable obtaining an acceptable quality. Doctor blades are to a large extent manufactured so that carbon fiber is used as the reinforcing material, as it is excellent for the tip of the doctor blade. Carbon reinforcement is a suitably hard material but it does not however, damage the roll surfaces, which is what for example some glass fiber are suspected to do. Doctor blades manufactured of this kind of a carbon fiber-reinforces are, however, still made of the same material all over, or alternatively at least they are in the thickness direction essentially symmetric whereby the composite is formed of alternating layers of different reinforced materials. The reason for this is considered to be the different internal tensions of the various materials which, in order to meet the straightness requirement of the material, require symmetry of the composite material in the manufacture of the laminate.
  • the general object of the invention is to provide both a new type of a method for manufacturing a doctor blade, a doctor blade and a new type of a blade holder for use in the securing of the new type of a blade according to a preferred embodiment of the invention to the body.
  • one of the main objects of the invention is to manufacture a composite of thermoplastic material reinforced with glass-fiber or other reinforcing material inexpensive to purchase, to be used as the body portion of a doctor blade and to connect to the body material mentioned the tip portion of a doctor blade (the so-called wearing part) manufactured of a thermoplastic composite of thermoplastic material reinforced with carbon fibers or other fibers producing the corresponding properties, or a combination of carbon fibers and glass fibers.
  • Another main object of the invention is to design the doctor blade asymmetric whereby the doctor blade wears out during the first wearing stage a little faster but still retains its form, in other words the tip of the blade remains sharp during the whole wearing stage.
  • a third main object of the invention is to develop a more economical method of manufacturing a doctor blade than before, according to which only the parts, in other words the tip portion/portions, where more expensive materials, as far as the properties are concerned, are needed are manufactured of these materials.
  • doctor blade of fiber- reinforced material It is characteristic of a method of manufacturing a doctor blade of fiber- reinforced material according to second preferred embodiment of the invention that the doctor blade is manufactured in the thickness direction of at least two asymmetric fiber- reinforced portions joined together.
  • doctor blade It is characteristic of a doctor blade according to a preferred embodiment of the invention for paper, board, finishing or tissue machines, the doctor blade comprising a tip portion disposing against the surface of a roll or a cylinder, and the doctor blade comprising at least two layers of different fiber-reinforced plastic materials, that the doctor blade comprises mainly two plastic material layers so that one of the layers forms at least the main portion of the doctor blade body and one side surface of the doctor blade, an the other layer made of a more wear- resisting material at least partly forms the second opposite side surface of the doctor blade.
  • doctor blade It is characteristic of a doctor blade according to a second preferred embodiment of the invention for paper, board, finishing or tissue machines, the doctor blade including a tip disposing against the surface of a roll or a cylinder, and the doctor blade being formed of at least two layers of different fiber-reinforced plastic material, that the doctor blade comprises in the width direction at least two plastic material layers of different fiber-reinforced materials so that one of the layers forms at least the main portion of the body of the doctor blade and the other layer forms at least partly the tip of the doctor blade.
  • the doctor blade according to the invention provides for example the following advantages compared with prior art doctor blades: inexpensive manufacturing costs (savings in the use of carbon fiber), optimized material consumption, savings in materials, environmentally friendly,
  • the blade holder according to the invention can be used both with prior art blades and new types of blades it can easily be adjusted according to the requirements of any application where the blades are used either by using specific fitting means or by manufacturing it to fit into the securing means in that particular application.
  • Fig. 1 illustrates a prior art apparatus and its application
  • Fig. 2 illustrates another prior art apparatus and its application
  • Figs. 3a - 3d illustrate prior art blade - blade holder combinations and apparatus used in securing them to the body
  • Figs. 4a, 4b and 4c illustrate the wearing of a prior art doctor blade
  • Fig. 5 illustrates schematically a doctor blade according to a preferred embodiment of the invention
  • Fig. 6a illustrates schematically a doctor blade according to another preferred embodiment of the invention
  • Fig. 6b illustrates schematically a doctor blade according to Fig. 6a in combined according to a further embodiment of the invention
  • Fig. 7a illustrates a blade holder according to a preferred embodiment of the invention in combination with a blade according to a preferred embodiment of the invention
  • Fig. 7b illustrates a blade holder according to another preferred embodiment of the invention in combination with a blade according to a preferred embodiment of the invention
  • Fig. 7c illustrates a blade holder according to a third preferred embodiment of the invention and a blade according to a preferred embodiment of the invention
  • Fig. 8 illustrates the used of a blade holder according to the invention with a conventional blade.
  • FIG. 1 illustrates a prior art treatment apparatus, described more in detail in Fl patent application no. 20035010, as fitted to cooperate with a moving surface 10.
  • This moving surface 10 is a paper machine roll or a cylinder 11 , of which only a small portion has been illustrated.
  • the treatment apparatus is meant for treating a moving surface.
  • the treating means is a doctor and it is designed to remove impurities from the surface in question or for example in some paper machine positions to detach the web itself.
  • the surfaces of various cylinders and fabrics are moving surfaces.
  • the treatment apparatus is used for example in coating a web, in which case coating paste is applied onto the surface of a moving web. This alternative has been illustrated in Figure 2.
  • the apparatus further comprises a body 12 provided in the vicinity of the surface 10 to be treated.
  • the body 12 comprises a bar 13 supported to the structure of the paper machine and turnable on a shaft 14.
  • the bar is locked to the correct position by means of turnbuckle screws (not illustrated).
  • the bar can be turned with loading members towards the surface in order to improve the scraping result or to compensate the wearing of the doctor blade.
  • the treating apparatus further comprises a blade holder 15, which according to the Fl patent application mentioned has been manufactured to essentially form a single uniform piece.
  • the blade holder 15 has been connected to the body 12 via a securing means 19.
  • the means actually treating the surface is a blade 16 disposed in the blade holder 15; the dimensioning and the material of the blade can vary depending on the application.
  • Figure 1 illustrates a scraping blade and Figure 2 a coating blade. The difference is to seen mainly in the location of the blade in connection with the roll; a scraping blade is directed against the rotating direction of the roll and a coating blade in the rotating direction of the roll.
  • the blade 16 comprises a scraping edge located at the longitudinal edge of it further away from the blade holder, the scraping edge being disposed to contact the moving surface 10 by moving the blade holder 15. Then the moving surface becomes treated.
  • Figures 1 and 2 illustrate a so-called stiff blade holder 15, whereby the movement of the blade holder 15 is accomplished by turning the bar 13.
  • the blade holder 15 illustrated in Figures 1 and 2 further comprises a separate top plate or a pressing blade 18 one side of which is disposed to the blade holder 15. Correspondingly, the other side of the pressing blade 18 extends closer to said edge than the blade holder 15, thus supporting the blade 16.
  • the blades 16 are illustrated unused. In practice the edge of the blade wears down and in the end it is chamfered to the other direction. In practice it is also possible to grind in the blade a chamfer corresponding to that of a worn blade.
  • the movement direction of the surface 10 has been illustrated with an arrow.
  • FIGS 3a - 3d illustrate a prior art blade holder and also a prior art blade more in detail than the previous figures.
  • the blade holder according to said Fl patent application 20035010 has been detachably disposed in the body 12 by means of a form locking 20, 21.
  • the form locking has been arranged to be steady in the width direction of the blade 16 (in the machine direction) and essentially free in the longitudinal direction of the blade 16.
  • the blade holder 15 can be moved in the longitudinal direction of the blade, in other words in the transverse direction of the machine.
  • the blade holder of a paper machine can be simply installed by pushing from the side and correspondingly removed by pulling.
  • the first securing means 20 of the securing means pair 19 is a contoured projection.
  • a second securing means 21 has been disposed to cover the first securing means 20 essentially at opposite sides. Then the second securing means 21 forms a groove for the projection-like first securing means 20.
  • the location of the securing means can vary.
  • the securing means is preferably disposed in the back part in the direction of the blade holder. Then the blade is secured at the front part of the blade holder.
  • the front part means the portion of the blade holder closest to the surface to be scraped.
  • the securing means structure described allows free positioning of the blade holder and the blade holder can be designed optimal in view of the loading and the securing of the blade. At the same time disadvantageous protruding elements are avoided which would collect impurities and would be liable to be damaged.
  • a fitting member 22 In existing bodies there are usually spiral holes for the securing of the blade holder. Then the securing of the blade holder 15 is easy by using a fitting member 22 according to the invention.
  • one of the securing means of the securing means pair is disposed in a separate fitting member meant to be secured to the body. Securing screws have been illustrated in Figures 3a and 3b with dotted lines.
  • FIG. 1 A first alternative embodiment of the fitting member 22 is illustrated in Figure 1.
  • the fitting means forms together with the body 12 a securing means for the contoured projection-like securing means of the blade holder 15.
  • the structure presented is very compact and the fitting means is easy to attach to the body 12. Further, even the arm portions of prior art blade holders having a composite structure can by appropriate machining be formed to projection-like securing means. In practice it is, however, more advantageous to finish the blade holder during the manufacture, whereby the structure of the blade holder is uniform.
  • the next embodiments of the fitting member 22 are illustrated in Figures 3a and 3b in which the same reference numbers are used for the functionally similar parts. In these figures one of the securing means 20 or 21 have been provided entirely in the fitting member 22. Then the fitting member 22 can be permanently secured to the body 12 with the bolts or screws illustrated with the dotted lines.
  • FIG 3a a projection-like securing means 20 has been provided in the fitting member 22 while the groove-like securing means 21 is in the blade holder 15. Then the form locking is well protected from fouling. Further, the blade holder 15 can be designed favorable in view of the manufacture.
  • the fitting member 22 further comprises a bend 23 which compensates the change in the location of the blade 15 compared with a conventional blade holder. Due to the fitting member 22 the blade 16 extends closer to the surface 10 and thus in most cases the blade angle of the blade 16 changes in relation to the surface. When the blade holder 15 according to Figure 1 is extended the blade angle is reduced which usually has a negative impact on the scraping result.
  • the blade holder By moving the blade holder in the height direction the problem described is avoided or at least it is avoidable by adjusting the bar and its location. If necessary, the installation of the fitting member in the body can also be reversed. Also the degree and form of the bend , can vary, in different applications. When manufacturing new treatment apparatus, the fitting member can be omitted. This is possible by arranging one of the securing means 20 or 21 of the securing means pair 19 straight in the body 12. This is illustrated in the embodiments of Figures 3c and 3d. In particular the blade holder 15 of the figures 3d can be manufactured very short which allows installing it in confined positions.
  • adjustable blade holders are used today, in which the body stays in place while the blade holder turns.
  • the blade holder according to the figures presented above can be adjustable.
  • the securing means of the pair of securing means are designed to form a mutually functional joint. Then a change of angle between the securing means is possible while the locking of the blade in the width direction remains unchanged.
  • One way of providing the blade holder adjustable is to design the securing means of the blade holder more open. Then the form locking is preserved while movement of the blade holder is still possible. In order to determine the movement, for example loading means can be provided between the securing means and the blade holder.
  • FIG. 1 - 3d The blade holder illustrated in Figures 1 - 3d has been designed to allow insertion of various kinds of blades.
  • Figure 3 illustrates a thick plastic blade, in addition to which also thin metal or composite blades can be used. Due to the design of the blade holder the securing of thin blades can be carried out in many different ways.
  • Figure 3c shows an ordinary rivet 28 while figure 3d illustrates a composite blade secured with a particular adapter 29.
  • the corresponding composite blade of Figure 3d there is a larger and as to its form different expansion 30 in the back part whereby a separate adapter is unnecessary.
  • there is a gap 32 in the blade holder for the blade 16 defined by a pressing blade 18 serving as an upper jaw and by a lower jaw 33.
  • the pressing blade is of an essential importance.
  • the pressing blade 18 is similar to the blade 16.
  • a form-locking means 34 for securing the pressing blade 18 detachably to the blade holder 15.
  • the pressing blade like the blade holder, is quick-locking and easily replaceable. Further, when choosing and manufacturing a pressing blade, the know-how and manufacturing methods of blades can be utilized which, simplifies the manufacture of the treatment apparatus and reduces costs.
  • FIGs 4a, 4b and 4c illustrates wearing of a prior art doctor blade 16.
  • the longitudinal edge of the doctor blade has been chamfered and the doctor blade has just been introduced into use and the tip 36 on its inner surface 35 (the trailing surface in the clockwise rotating direction of the roll 11) has not worn down at all, yet.
  • the tip 36 is sharp and performs well its function of cleaning the roll 11.
  • the doctor blade has been used for a period of time and the tip 36 of the doctor blade 16 has worn round for example due to process reasons. At this stage the doctor blade 16 allows fibers and other impurities to pass with the surface of the roll 11 and thus does not perform properly its task.
  • a new type of a doctor blade has been developed, the characteristic feature of a first embodiment of which is that one of the surfaces of the blade is manufactured of a material having improved wear-resistance properties, or is provided with such material, whereby the blade material having weaker wear-resistance properties wears out more easily and in a way leaves the maintaining of the surface pressure to be taken care of by the surface layer having better wear-resistance properties.
  • a doctor blade according to this alternative embodiment of the invention is formed of a basic composite having weaker wear-resistance properties constituting the main portion of the blade thickness and including one side surface of the blade, and of a surface composite having stronger wear-resistance properties, the surface composite being located only on one planar surface of the doctor blade or in the vicinity of it.
  • the basic reinforcement of the doctor blade is composed of machine direction glass fibers present essentially along the entire thickness of the blade.
  • the glass fibers can exist either as individual fibers of as orientated felt; these may be provided in several layers.
  • One surface corresponds to the outer surface 38 of the doctor blade in Figs.
  • the basic reinforcing material in a doctor blade is either non-orientated glass fiber felt or woven glass fiber fabric in one or several layers, carbon fibers orientated in the direction mentioned being provided on one surface of the basic reinforcement mentioned.
  • Said carbon fibers are tied to the glass fiber felt/fabric/reinforcement in the Z direction by stitching, entanglement, sewing or by some other suitable method, followed by impregnation with resin and curing as described above.
  • the doctor blade 40 according to a third preferred embodiment of the invention illustrated in Figure 5 eliminates the problem described above so that the outer surfaces, i.e. the coating 44 (illustrated with dotted lines) of the chamfered portion 42 and the outer surface layer 46 of the doctor blade have been manufactured of a material which wears down more weakly than the rest of the doctor blade, i.e. of a harder material.
  • the outer surface 46 of the doctor blade is manufactured for example in the way described in the preceding embodiments of a harder carbon fiber material or of a compound of carbon and glass fiber materials than the main portion 48 of the doctor blade.
  • the coating 44 of the chamfered portion 42 in turn is preferably of a hard material such as for example ceramic, glass, metal ceramic, metal or a corresponding material.
  • a hard material such as for example ceramic, glass, metal ceramic, metal or a corresponding material.
  • FIG. 6a illustrates another alternative preferred embodiment of the doctor blade 60.
  • the doctor blade is formed of a rectangular elongated plate-like piece having two planar side surfaces, two longitudinal edges and two transverse edges.
  • the doctor blade has been manufactured clearly of different materials in the width direction of the doctor blade, i.e. in ' the machine direction.
  • the doctor blade 60 comprises a body portion 62 and a tip portion 64 subjected to wear.
  • the body portion 62 of the doctor blade 60 may be manufactured for example of a plastic material reinforced with glass fibers or other corresponding advantageous fibers.
  • the tip portion 64 of the doctor blade 60 may be produced a plastic material reinforced with carbon fibers, a combination of carbon fibers and glass fibers or other fibers giving corresponding usage properties.
  • the plastic material may be thermosetting plastic or thermoplastic.
  • thermosetting plastic suitable for this purpose are epoxy, phenolic resin and vinyl esters and vinyl ester hybrids for example with urethane (vinyl ester urethane, VEUH) and polyether amide.
  • suitable thermoplastics are polyolefins, polyamides, polyetherether ketone (PEEK), polyether sulfone (PES), polyether imide (PEI), polyamide imides (PAI).
  • the components When using thermoplastic, the components may be manufactured separately and joining the components to each other is possible for example by welding so that the plastic materials, which may be the same in both the components although the reinforcing fibers are different, are remelted at the boundary surfaces of the components 62 and 64 and subsequently the components are pressed together.
  • the plastic materials and the manufacturing method mentioned may be used also in the manufacture of the doctor blades comprising different layers in the thickness direction described above in connection with Figures 4 and 5. Quite in the corresponding way the doctor blade structure described in connection with Figures 4 and 5 may be used in doctor blades having sharp edges on both longitudinal sides of the blade.
  • thermosetting plastic When thermosetting plastic is used as the plastic material the manufacture can take place by pressing or for example by pultrusion so that the fiber material having enhanced strength or other properties, such as carbon fiber or a fiber material essentially containing carbon fiber, is provided only in the area forming the tip of the doctor blade, glass fiber being provided on the rest of the area.
  • the fiber material is supplied in this way to a mold, impregnated with thermosetting plastic resin and pressed at an elevated temperature and pressure to form a doctor blade blank. The blank is removed from the mold and machined at the area of the tip to a chambered form.
  • the carbon fiber material impregnated with resin or a corresponding material is supplied to a mold, in other words to a pultrusion nozzle to the desired area forming the tip and resin-impregnated glass fiber is supplied to the remaining area.
  • the fibers may be supplied via the same resin bath but in theory it is possible to use different resins for different types of fibers, presupposing that the process and usage properties of the resins are compatible. For example when a conventional narrow blade blank is produced (one blade width) the carbon fiber or a corresponding material is supplied to one side of the pultrusion nozzle to a somewhat narrow area, approx. 1/4 - 1/6 of the area, while the rest of the fiber material is glass fiber.
  • a double-edged blade is to be prepared (Fig. 6b)
  • carbon fiber is supplied correspondingly to both edges of the nozzle and glass fiber to the center.
  • the carbon fiber or a corresponding material is supplied to the center portion of the nozzle, whereby, by splitting the blank in the longitudinal direction at the center in two parts and machining the edges of the splitting point to a chamfered configuration, two blades are produced.
  • Figure 6a illustrates a further alternative embodiment, in other words a way in which the embodiment of Figure 5 may be combined with a new type of a doctor blade.
  • the Figure illustrates how it is possible to provide the outer surface of the tip portions 64 of the doctor blade 60 with a layer 66 of a harder material than the material of the main portion of tip.
  • One alternative is to form the layer 66 of carbon fibers orientated in the machine direction in the way described above in chapters 40 - 43.
  • the chamfered portion of the tip portion may be provided with the hard coating described in connection with Figure 5.
  • Figure 6b in turn illustrates a doctor blade manufactured according to Figure 6a but constructed so that both its sides can be used.
  • both the long edge or side portions 64' and 64" of the doctor blade of Figure 6b have been chamfered and manufactured essentially of carbon fiber-reinforced material or a compound of glass and carbon fiber materials whereas the center portion 62' of the doctor blade has been produced of a glass fiber reinforcement or a corresponding less expensive material.
  • Figure 6b further indicates with dotted lines a protruding element 94 disposed, when desired, on one side surface of the blade essentially at the longitudinal center line, by means of which the doctor blade can be installed into the blade holder so that it can be pulled out from the blade holder in the longitudinal direction, turned and pushed back in order to introduce the other blade tip into use.
  • the harder outer surface layer and/or the coating of the chamfered portion illustrated in Figure 5 can be applied also to the structure of this embodiment.
  • the protruding element of one side surface of the doctor blade described above can be used also with the doctor blades described in connection with Figures 4 and 5, in other words with doctor blades where one side surface has been manufactured of a harder material than the other one.
  • Figure 7a illustrates a blade holder 70 according to a preferred embodiment of the invention and also a blade 90 according to a preferred embodiment of the invention illustrated in Figure 6b.
  • the doctor blade according to the invention comprises sharp edges on both longitudinal sides of the blade. In order to improve the wear resistance the edges may be coated with ceramic, metal or metal ceramic.
  • the upper part of the blade holder according to Figure 7, i.e. the upper jaw 72 is in the figure similar to for example that of the prior art blade holder disclosed above ( Figures 1 - 3d).
  • the lower part, i.e. the lower jaw 74 of the blade holder 70 according to a preferred embodiment of the invention differs essentially from the prior art approaches.
  • the blade 90 is supported in the machine direction, i.e. in its width direction to another recess 78 located in the tip portion 80 of the lower jaw 74 of the blade holder 70, in other words closer to the outer edge 82 of the blade holder as seen from the body 70.
  • the recess 78 is separated from the inner recess of the blade holder by a planar surface 98 which in this embodiment can be considered to continue as planar surface 96 between the recess 78 and the tip of the lower jaw, the other side surface of the doctor blade being located against both these planar surfaces so that the doctor is supported to the blade holder in a non-swinging manner so that the other edge 92 of the doctor blade located in the recess does not touch the bottom of the recess 76.
  • Co-operating with the recess 78 there is a longitudinal protrusion provided in one side surface of the blade 90 according to the invention, a series of rivets or corresponding means 94 with which the blade 90 may be locked in the machine direction in place in the blade holder 70.
  • the protrusion or the corresponding member 94 is set against the back wall 78' of the recess 78 of the blade holder 70.
  • the protrusion 94 extending along the entire length of the blade 90, or the series of protrusions arranged in a corresponding way are essentially located at the center line of the blade 90 whereby both edges of the blade 90 may be used.
  • the expression 'essentially at the center line' also covers the structural alternative where the protrusion or the series of protrusions may be provided also slightly off from the center line of the blade 90. This may de done when the wearing allowance of the blade is taken into account.
  • the protrusion or protrusions may be located at the center line of the blade when one of the edges of the blade has worn down and the other one has not been touched.
  • the protrusion 94 mentioned may be a separate rivet, a profile, or a portion provided in the blade during its manufacture, for example when manufacturing the blade by pultrusion.
  • a blade 90 according to the invention is turned around and the operation can continue by using the edge of the same blade in the longitudinal side of the blade, referred to in the figure with number 92.
  • the blade may be supported also in the approach of the invention in a known way with a pressing blade 48, which is located with the blade in the gap 84 between the upper jaw 72 and the lower jaw 74 of the blade holder 70 and presses the doctor blade against the planar surfaces 96 and 98.
  • the pressing blade is locked with form locking at its side facing the blade holder to the groove at the bottom of the gap.
  • the blade may be replaced so that the longitudinal locking of the blade, if such is used, is opened (for example by removing the locking pin inserted in the protrusion 94 through the low jaw 74 of the blade holder), the blade is pulled in the longitudinal direction out from the holder, it is turned around and pushed back to the holder so that the edge 92 of the side is set against the surface to be treated.
  • FIG. 7b illustrates a blade holder according to another preferred embodiment of the invention, in which the design of the low jaw 74 of the holder has been slightly modified compared with the blade holder illustrated in Figure 7a.
  • the blade holder 70 may be of the type illustrated in Figure 7b, thus lower jaw 74 of the blade holder is provided with one recess 78, only, located in the tip portion of the lower jaw at a distance of at least one half of the width of the blade from the bottom 86 of the groove provided for the blade 90 in the gap 84 of the blade holder 70.
  • FIG. 7c in turn illustrates a blade 90' according to another preferred embodiment of the invention, the blade causing and/or facilitating modifications also in the blade holder 70.
  • the doctor blade 90' of this invention which blade may, preferably but not necessarily, be of a type described in connection with Figures 4, 5 and 6, there are at one of its side surfaces two protrusion 94' and 94" . or series of projections extending in the longitudinal direction of the blade essentially at equal distances from the longitudinal center line of the blade 90'. Also here the term 'essentially at equal distances' must be understood so that if desired the wearing allowance of the blade may be taken into account the way described in chapter 50.
  • the blade 90' leans in the width direction, i.e.
  • FIG 8 still illustrates how a blade holder according to Figure 7a may be used with a conventional one-sided blade 16, whereby the side of the blade opposite the edge 17 of the blade 16 rests against the back surface 86 of the inner recess.
  • a conventional blade of a blade of the new type it is possible to use in the blade holder according to Figure 7a either a conventional blade of a blade of the new type.
  • Yet another embodiment of the invention is manufacturing the tip portion of the doctor blade of a material where friction-reducing particles such as for example Teflon have been mixed into the matrix, the resin.
  • the diameter of these particles is preferably about 20 ⁇ m. These particles reduce the friction between the blade and for example a ceramic roll, thus allowing reduced wearing of the blade, lower heat formation and savings in energy consumption.

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Abstract

La présente invention concerne une racle pour papier, carton, machines de finition et à ouate, ainsi qu'un procédé de fabrication de racle. La racle comprend une pointe disposée contre la surface d'un rouleau ou d'un cylindre. La racle se compose d'au moins deux couches différentes en matériau plastique renforcé de fibres. La racle de la présente invention et son procédé de fabrication se caractérisent en ce que la racle comporte principalement deux couches de matériau plastique. L'une des couches forme au moins la partie principale du corps (48) de la racle (40) et l'une au moins des surfaces latérales de la racle (40). L'autre couche (46), composée d'un matériau plus résistant à l'usure, forme au moins partiellement l'autre surface opposée latérale de la racle (40).
PCT/FI2007/050513 2006-09-27 2007-09-25 Procédé de fabrication de racle, racle et porte-racle WO2008037850A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE200711002273 DE112007002273T8 (de) 2006-09-27 2007-09-25 Verfahren zum Herstellen einer Rakelklinge, Rakelklinge und Klingenhalter

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
FI20065601A FI20065601L (fi) 2006-09-27 2006-09-27 Terä ja teräpidin
FI20065601 2006-09-27
FI20065602A FI20065602L (fi) 2006-09-27 2006-09-27 Kaavinterä ja menetelmä sen valmistamiseksi
FI20065602 2006-09-27

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WO2008037850A1 true WO2008037850A1 (fr) 2008-04-03

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DE (1) DE112007002273T8 (fr)
WO (1) WO2008037850A1 (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1975316A1 (fr) * 2007-03-30 2008-10-01 Aikawa Iron Works Co., Ltd. Dispositif de racloir et procédé d'échange de lame pour dispositif de racloir
WO2011092064A1 (fr) * 2010-01-28 2011-08-04 Voith Patent Gmbh Raclette
CN102652197A (zh) * 2009-12-11 2012-08-29 美卓造纸机械公司 用于纤维幅材机的刮刀片及纤维幅材机中的刮刀装置
US8771473B2 (en) 2009-12-11 2014-07-08 Valmet Technologies, Inc. Doctor blade for a fiber web machine and doctor arrangement in a fiber web machine
DE102013007602A1 (de) * 2013-05-03 2014-11-06 Schattdecor Ag Verfahren zur Herstellung einer bedruckbaren ein- oder mehrschichtigen Materialbahn sowie eine danach hergestellte Materialbahn und eine zugehörige Anlage zur Herstellung einer derartigen Materialbahn
CN108532352A (zh) * 2018-03-26 2018-09-14 赣州恩创科技有限公司 一种起皱刀及其制备方法
EP3904593A1 (fr) * 2020-04-30 2021-11-03 Joh. Clouth GmbH & Co. KG Racleur à découpe pour feuilles de matières flexibles à partir d'un rouleau

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GB978988A (en) * 1962-12-14 1965-01-01 Lodding Engineering Corp Doctor blade
GB2128551A (en) * 1982-10-13 1984-05-02 Inventing Ab Scraper with wear-resistant coating
WO2003060231A1 (fr) * 2002-01-11 2003-07-24 S.D. Warren Services Company Lames de docteur composites
FI114328B (fi) * 2003-01-30 2004-09-30 Metso Paper Inc Komposiittirakenteinen käsittelylaitteisto
FI116689B (fi) * 2004-12-17 2006-01-31 Metso Paper Inc Komposiittinen kaavinterä

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US4549933A (en) 1983-07-05 1985-10-29 Thermo Electron Corporation Doctor blade with non-homogeneous stiffness properties
FI101637B1 (fi) 1997-09-11 1998-07-31 Valmet Corp Hoitava kaavarinterä ja menetelmä sen valmistamiseksi
US6491754B1 (en) 2000-06-13 2002-12-10 Voith Sulzer Paper Technology North America, Inc. Carbon fiber doctor blade
US6565712B2 (en) 2001-05-17 2003-05-20 Lingol Corporation Composite
FIU20010246U0 (fi) 2001-06-15 2001-06-15 Metso Paper Inc Järjestely paperi- tai kartonkikoneen hihnan tai pehmeän telapinnoitteen kaapimiseksi

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB978988A (en) * 1962-12-14 1965-01-01 Lodding Engineering Corp Doctor blade
GB2128551A (en) * 1982-10-13 1984-05-02 Inventing Ab Scraper with wear-resistant coating
WO2003060231A1 (fr) * 2002-01-11 2003-07-24 S.D. Warren Services Company Lames de docteur composites
FI114328B (fi) * 2003-01-30 2004-09-30 Metso Paper Inc Komposiittirakenteinen käsittelylaitteisto
FI116689B (fi) * 2004-12-17 2006-01-31 Metso Paper Inc Komposiittinen kaavinterä

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1975316A1 (fr) * 2007-03-30 2008-10-01 Aikawa Iron Works Co., Ltd. Dispositif de racloir et procédé d'échange de lame pour dispositif de racloir
CN102652197A (zh) * 2009-12-11 2012-08-29 美卓造纸机械公司 用于纤维幅材机的刮刀片及纤维幅材机中的刮刀装置
US8771473B2 (en) 2009-12-11 2014-07-08 Valmet Technologies, Inc. Doctor blade for a fiber web machine and doctor arrangement in a fiber web machine
WO2011092064A1 (fr) * 2010-01-28 2011-08-04 Voith Patent Gmbh Raclette
DE102013007602A1 (de) * 2013-05-03 2014-11-06 Schattdecor Ag Verfahren zur Herstellung einer bedruckbaren ein- oder mehrschichtigen Materialbahn sowie eine danach hergestellte Materialbahn und eine zugehörige Anlage zur Herstellung einer derartigen Materialbahn
RU2661211C2 (ru) * 2013-05-03 2018-07-13 Шаттдекор Аг Способ изготовления пригодного для печати одно- или многослойного полотна материала, а также изготовленное этим способом полотно материала и соответствующая установка для изготовления такого полотна материала
CN108532352A (zh) * 2018-03-26 2018-09-14 赣州恩创科技有限公司 一种起皱刀及其制备方法
CN108532352B (zh) * 2018-03-26 2024-03-29 赣州恩创科技有限公司 一种起皱刀及其制备方法
US11951708B2 (en) 2018-03-26 2024-04-09 Ganzhou En Chuang Technology Company Limited Creping blade and method for manufacturing same
EP3904593A1 (fr) * 2020-04-30 2021-11-03 Joh. Clouth GmbH & Co. KG Racleur à découpe pour feuilles de matières flexibles à partir d'un rouleau

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DE112007002273T5 (de) 2009-08-13

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