CA2071948A1 - Doctor blade for use in coating continuous strips of material or similar substrates - Google Patents
Doctor blade for use in coating continuous strips of material or similar substratesInfo
- Publication number
- CA2071948A1 CA2071948A1 CA002071948A CA2071948A CA2071948A1 CA 2071948 A1 CA2071948 A1 CA 2071948A1 CA 002071948 A CA002071948 A CA 002071948A CA 2071948 A CA2071948 A CA 2071948A CA 2071948 A1 CA2071948 A1 CA 2071948A1
- Authority
- CA
- Canada
- Prior art keywords
- doctor blade
- blade element
- thickness
- blade
- metering
- 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.)
- Abandoned
Links
- 239000000463 material Substances 0.000 title claims abstract description 21
- 239000011248 coating agent Substances 0.000 title claims description 56
- 238000000576 coating method Methods 0.000 title claims description 56
- 239000000758 substrate Substances 0.000 title 1
- 230000008859 change Effects 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 7
- 238000011144 upstream manufacturing Methods 0.000 claims description 7
- 239000002184 metal Substances 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 claims description 5
- 229920003002 synthetic resin Polymers 0.000 claims description 3
- 239000000057 synthetic resin Substances 0.000 claims description 3
- 239000000203 mixture Substances 0.000 claims description 2
- 229920003051 synthetic elastomer Polymers 0.000 claims description 2
- 239000005061 synthetic rubber Substances 0.000 claims description 2
- 230000004048 modification Effects 0.000 claims 1
- 238000012986 modification Methods 0.000 claims 1
- 230000007480 spreading Effects 0.000 abstract description 4
- 238000003892 spreading Methods 0.000 abstract description 4
- 238000005452 bending Methods 0.000 abstract 2
- 238000011068 loading method Methods 0.000 description 6
- 239000008199 coating composition Substances 0.000 description 5
- 230000009471 action Effects 0.000 description 4
- 230000001419 dependent effect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 238000003801 milling Methods 0.000 description 2
- WTEVQBCEXWBHNA-YFHOEESVSA-N neral Chemical compound CC(C)=CCC\C(C)=C/C=O WTEVQBCEXWBHNA-YFHOEESVSA-N 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 102000007469 Actins Human genes 0.000 description 1
- 108010085238 Actins Proteins 0.000 description 1
- WTEVQBCEXWBHNA-UHFFFAOYSA-N Citral Natural products CC(C)=CCCC(C)=CC=O WTEVQBCEXWBHNA-UHFFFAOYSA-N 0.000 description 1
- 241000489861 Maximus Species 0.000 description 1
- 229910000639 Spring steel Inorganic materials 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- ANTSCNMPPGJYLG-UHFFFAOYSA-N chlordiazepoxide Chemical compound O=N=1CC(NC)=NC2=CC=C(Cl)C=C2C=1C1=CC=CC=C1 ANTSCNMPPGJYLG-UHFFFAOYSA-N 0.000 description 1
- WTEVQBCEXWBHNA-JXMROGBWSA-N citral A Natural products CC(C)=CCC\C(C)=C\C=O WTEVQBCEXWBHNA-JXMROGBWSA-N 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 239000013013 elastic material Substances 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000002674 ointment Substances 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000005060 rubber Substances 0.000 description 1
- 238000005488 sandblasting Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 125000003696 stearoyl group Chemical group O=C([*])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000010345 tape casting Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C11/00—Component parts, details or accessories not specifically provided for in groups B05C1/00 - B05C9/00
- B05C11/02—Apparatus 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
- B05C11/04—Apparatus 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
- B05C11/045—Apparatus 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 the blades themselves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C11/00—Component parts, details or accessories not specifically provided for in groups B05C1/00 - B05C9/00
- B05C11/02—Apparatus 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
- B05C11/04—Apparatus 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
- B05C11/041—Apparatus 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
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
- D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
- D21H23/22—Addition to the formed paper
- D21H23/32—Addition to the formed paper by contacting paper with an excess of material, e.g. from a reservoir or in a manner necessitating removal of applied excess material from the paper
- D21H23/34—Knife or blade type coaters
- D21H23/36—Knife or blade forming part of the fluid reservoir, e.g. puddle-type trailing blade or short-dwell coaters
Landscapes
- Coating Apparatus (AREA)
- Paper (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
- Soft Magnetic Materials (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
- Heat Treatment Of Sheet Steel (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
The aim of the invention is to make it possible to vary independently of each other, i.e. better and more freely, the basic parameters in the design of a squeegee used as a flexible-plate doctor blade in a coating-material spreading device. These parameters may include the length of the chamfered surface in contact with the surface to be coated, the resistance to bending strain parallel to the spreading edge of the blade and the resistance to bending strain at right angles to the spreading edge of the blade. This aim is achieved by virtue of the fact that the flexible-blade doctor blade (squeegee) proposed does not have a constant thickness but is made up of two or more different cross-sections with steps parallel to the dosing edge (8), thus giving the flat sides of the doctor blade a substantially terrace-like structure. The blade may also have grooves parallel to the dosing edge.
Description
2~71g~
The invention relates to a doctor blade element in accordance with the preamble of claim 1. Such a doctor blade element is disclosed in the German patent publication 2,637,827 A1, and the German patent publication 2,939,906 A1 and furthermore the periodical "Der Polygraph" 9/74, pages 606 through 612.
For the coating of webs of material, more particu1arly spread coating on paper or board, it frequently occurs that a doctor blade element having the form of a strip springj a so-called spreading blade, is utilized for metering out the coating composition on the length of material or furthermore on a support or applicator roll, which at its metering end has an oblique chamfered metering surface, which is thrust by a support against the web of material or an applicator roll. In this respect the coating weight is predetermined by the equilibrium between the mechanical force at the metering surface and the hydrodynamic opposing force of the composition utilized for coating. This equilibrium may frequently be disturbed by fluctuations in the properties of the paper, of the coating composition, of the elastic cover of the support roll bearing the web of material or of the carrying system for the doctor blade element. The elasticity of the spreacling blade, which is generally manufactured of spring steel, is to a certain extent able to compensate for such interfering factors so that generally a stable equ;librium is maintained.
Should another coating weight be desired or if a parameter - such as for instance the web speed - is modified, it is then necessary for the mechanical force acting on the chamfered metering surface to be altered.
In the case of the initially mentioned German patent publication 2,637,827 A1 an attempt was made to use a very thin construction of the coating blade in the metering zone in order to avoid or substantially reduce '~the danger of streaking owing to solid particles lodged underneath the - 30 chamfered metering surface. In the case of the two other publications theintention was to obtain a more even application of the ink over long periods of time by constant dimensions and geometry of the doctor blade in the part ,~ .,.
20719~
to be subjected to wear.
In contradistinction to this the aim of the present invention is to substantially increase the strength or rigidity of the blade and its self-vibration characteristics as regards producing a high degree of smoothness of the coating and to increase the coating weight range during coating with a blade.
However it would be generally an advantage if it were possible to make greater variations in the mechanical force at the chamfered metering surface in the case of a coating blade than has hitherto been the case. It would then be possible to cope with a greater range of variation in thc weight of coating.
Therefore the object of the invention is to reduce the limitation in the range of variation of the thrust forces by a suitable design of the blade in order in this manner to be able to provide a greater range of application than has so far been the case.
This object is to be attained by the features recited in the characterizing part of claim 1.
It has been recognized by the inventor that the reason for the considerable limitation in the range of parameters during coating with a blade is because there is a connection between the thickness of the blade and the length, dependent thereon~ of the chamfered metering surface (in the case of comparable angles and as seen in the direction of travel of the web), the flexural stiffness as dependent on the thickness of the blade in the direction of travel of the paper and on the flexural stiffness of the blade in the ~25 transverse direction.
;~ For instance in the case of a blade with a constant thickness a high coating weight is tied to a low loading thrust. In this respect the blade is only tensioned and bent to a slight extent and in this working position it ~- will be weak both in this working position and also in a ~irection perpendicular thereto. The lack of transverse and longitudinal rigidity leads to an uneven distribution of the coating in the trans~erse and in the longitudinal directions.
Furthermore the blade is quite prone to self-vibration which is responsible for an inferior distribution of the material to be applied within a range of some millimeters (so-called cloudiness or step formation in the applied coating).
Conversely a low coating weight is mutatis mutandis connected with a high loading thrust and pronounced flexure o,~ the blade and thus with a greater longltudinal and transverse rigidity. Therefore the desired elastic flexure, as already mentioned, of the coating blade is less satisfactory.
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Fluctuations are less well compensated for than in the case of a more elastic behavior.
One feature of the invention is that significant factors including the length of chamfer of the metering edge, the flexural stiffness along the coating edge and the flexural stiffness transversely in relation to it, are no longer linked to each other and that the self-vibration of the blade may be caused to take place in a higher frequency range by having a greater^blade tension, such range no longer being responsible for an undesired effect on the quality of the coating. This is ensured in such a manner that the doctor blade elements in accordance with the invention having the form of a strip spring (as coating blades) do not have a constant thickness and in fact have two or more different cross sections.
It may be seen from the theory of elasticity that the flexural stiffness of the blade is proportional to the third power of the thickness of the blade. Therefore the flexural stiffness of the blade in the transverse direction increases in the vicinity of tip of the blade in ~he case of a blade which is thicker at the tip.
In the thinner part of the blade the flexural stiffness is accordingly substantially lower, that is to say the result is a blade which in the direction of movement behaves like a weak spring while in the transverse direction at the tip it behaves like a hard spring.
The coating effect consequently has a greater leveling action than in the case of a blade with a constant thickness: the surface of the coating becomes more even. Conversely when coating using a blade which is thinner at the tip, the loss of flexural stiffness at the tip is minimized by making the thin part of the blade very short. In addition to this it is possible for there to be a specially designed rib part directly in the transitional part between the thin and the following thicker part, such rib part substantially increasing the flexural stiffness in the transverse direction and additionally modifying self-vibration.
In this respect the coating blade in accordance with the invention may have a minimum thickness of 0.25 mm, while in the case of the known arrangement of the type initially mentioned in the case of a chamfer angle of the metering surface of at the most 20 the maximum thickness amounts to 0.17 mm and preferably 0.14 mm. Furthermore the engagement angles of the doctor blade element resembling a strip spring (i. e. a coating blade) are substantial and are equal to 25' to 45 and preferably 30' ~o 35. This angle practically constitutes the chamfer angle between the chamfered metering surface and the upstream broad side of the coating blade, i.e. the angle a.
The invention will now be described in following account of working 2~719~8 embodiments of the invention as illustrated in the drawings.
Figure 1 is a side view of a conventional coating device using a blade in accordance with the invention.
Figures 2 through 7 show embodiments of the doctor blade element resembling a strip spring in accordance with the invention.
Herein the term strip spring is used in the sense of an element, which practically constitutes a piece of thick foil of highly elastic material, such material being able to be both a metal such as hardened or alloyed steel, or a highly elastic composite synthetic resin.
In figures 2 through 7 the breadth dimension of the elements is naturally exaggerated in relation to the length of the illustrated cross sections. The cross section of the doctor blade elements is here practically illustrated in side view as the outline, as is also the case in figure 1.
' In figure 1 the support or applicator roll B bearing the web W of material is only illustrated diagrammatically. The direction of rotation is as indicated by the arrow F. The coating blade representing the strip spring doctor blade element 1 is so arranged that the chamfered metering surface A
is in engagement with the applicator roll R or, respectively, the web W of material. If this chamfered metering surface is relatively broad as in the case of figures 2, 4 and 6, the said surface should naturally be ground in - alignment with the direction of coating prior to putting into operation.Furthermore this angle a between the chamfered metering surface A and the upstream broad side of the doctor blade element which is in engagement with the applicator roll, has to be very accurately set and maintained. For this purpose it is necessary to have regulating means as are for instance described in German patent 2,913,421. An even more exact regulating device is described in the German patent application 3,937,322.
The upstream broad side of the coating blade l with the upstream metering edge 8' is in this case the laft side, as is indicated by the drips of coating composition as shown in broken lines. The web of material receives this excess of coating composition somewhere upstream from the support or applicator roll R or in the vicinity of the angle of bend of the web W of material about the applicator roll R, this not being illustrated in detail. 35 The same applies, if the coating composition ls firstly only applied to the roll.
The coating blade 1 is here clamped and held in a holder 12 with a clamping rail 13. This leads to a clamping part B on the coating blade at its end opposlte to the chamfered metering surface A. The coating blade is thrust ~ 40 upon by load1ng plates 14 in its part freely extending out of the holder, such ', .
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2~7194~
plate 14 being in ~his case constituted by levers, adjustment in length of such levers being possible by means of screws 17 and belleville washers 18 in order to practically set the thrust acting on the coating blade. A basic adjustment is produced using the sliding plate-like carrier 15 for the loading plates 14. This way of holding for the coating blade is however only given as an example from a plurality of similar devices in the prior art. At the outlet of the coating blade from the holder there is at the end of the clamping part B a clamping line C on the end 9 (which is here the upper end) of clamping means or, respectively, a clamping rail 13.
10, Figure 2 shows a design of the strip spring doctor blade element in accordance with the invention, in the case of which the metering surface A is very broad and accordingly furthermore the so-called coating blade has a corresponding thickness. In this figure, as well as in the other figures, the - direction of movement of the web of material or the surface of the support or applicator roll is as indicated by the arrow F so that the upstream broad side of the coating blade is here in any event the left side. In all the figures the line of clamping is denoted by the letter C as shown in broken lines. In figure 2 there is a reduction in cross section at the step 3 so that towards the clamped end the coating blade becomes relatively smaller in its cross section. This blade is more particularly intended for high weights of application, in the case of which there will be a low thrust at the line L and ; correspondingly a low blade clamping effect. Owing to the great length of the chamfered metering surface A and owing to the greater thickness as far as step discontinuity 3 it is necessary for the clamping action of the blade to be considerably increased. Therefore it is possible to operate with the desired high weight of coating and simultaneously this blade will be bent to a greater extent in accordance with the greater blade tension and therefore it will be more rigid or stable.
In the converse case (see figure 3) - that is to say in the case of a very low weight of application - the chamfered metering surface A is relati-vely short and in this part the coating blade is relatively thin as far as a step discontinuity 2. The loading forces transmitted by the loading plates 14 are distributed only onto the smaller chamfered metering surface, something contributing to an increase in the loading thrust. Owing to the design in accordance with the invention with - as in this case - two different thicknesses, it is possible for the elasticity of the coating blade to be maintained within the desired range.
It is useful if the single step discontinuity 2 is placed at a dlstance from the downstream metering edge 8 equal to 0.04 to 0.5 times the distance between this metering edge 8 and the clamping edge C.
9 ~ 8 The blades in accordance with the invention make it possible to substantially increase the present day limits for coating with coating blades to achieve the following:
- a higher weight of application - a lower machine speed - a higher dry matter content and - reversed parameters or combinations thereof - better control of self-vibration of the blade.
In the embodiments of the invention illustrated in figures 4 and 5 in the case of blades for the application as in figure 2 and 3-tWQ steps 2 and 2' and, respectively, 3 and 3' in thickness are provided. Thus as shown in broken lines in figure 4 and 5 the change in cross section may also be stepless in order to approximate the change in cross section close to the computed step discontinuities as far as possible.
In figures 6 and 7 there is an overwhelmingly even change in cross section from the chamfered metering surface A as far as the clamped end of the doctor blade elements. In this respect it is a question of first terrace which always has a constant thickness in order to ensure that despite wear of the blade the length of the chamfer be constant.
It is preferred for the first step discontinuity to be at a distance from the downstream metering edge 8 equal to between 0.04 and 0.5 times the distance between this metering edge 8 and the clamped edge C and the second step discontinuity in a corresponding range between 0.06 times and 0.8 times the said distance from the first step discontinuity.
In ths case of a coating blade with a single step discontinuity it is - preferred for the thickness of the second step - taking the metering surface A as a basis - to be 5 % to 83 % of the first step and in the case of a change i in thickness in two step discontinuities - again taking the chamfered metering surface as a basis - the thickness of the second step is preferably equal to 6 % to 75 % of the thickness of the first step and the thickness of the third step is preferably equal to 25 æ to 83 % of the thickness of the second step.
It is furthermore preferable in the case of a single step ;; discontinuity for the same to be placed at a distance from the downstream'-;` meterlng edge 8 equal to between 0.04 times and 0.3 times the distance between this metering edge and the clamping line C. In this case it is then also an advantage if the thickness of the second step be between 150 and 240 %
of the first step.
In the case of there being two step discontinuities it is furthermore preferred to provide the first step discontinuity at a distance from the downstream metering edge 8 of between 0.25 times and 0.4 times the distance . ' .
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between this metering edge 8 and the clamping line C and to provide the second step discontinuity in a range between 0.4 times and 0.8 times the said distance. In this case it is preferred to ma~e the thickness of the second step equal to between 120 and 200 % of the thickness of the first step and the thickness of the third step equal to between 120 and 200 ~ of the thickness of the second step - in each case as measured from the chamfered metering surface A.
Furthermore in accordance with figure 8 it is possible to provide a stiffening rib 20 extending parallel to the metering edge ~ in the Form of a rail. This locally very limited increase in the cross section is intended to increase the transverse flexural stiffness at the tip of the blade and to produce a favorable change as regards the self-vibration of the blade at the tip. This rib is preferably at the most 5 mm thick and 3 mm broad and may start at a minimum distance from the matering edge 8 of 2 mm.
The rise or fall of this rib may be perpendicular or oblique and the ~; rib may be straight or curved.
- Figure 9 shows that a change in the cross section of the blade may also be produced by having grooves 21 or 22 parallel to the metering edge 8.
Additional grooves may also be provided in accordance with figure 10 20 in the case of a coating blade designed with step discontinuities. These grooves 21, 22, 23 or 24 may be rectangular, trapezoidal, rounded or triangular. It is possible for the grooves or steps to be produced by ~` removing material, preferably by grinding, milling, chemical or electrochemical milling, micro sand blasting or by similar methods, or also by laser light.
The additional grooves are preferably produced in the second step in order to provide for a further precise optimization of the longitudinal and transverse stiffness and of the self-vibration behavior of the doctor blade ; element.
In this respect the grooves preferably have a breadth of 0.1 to 05 mm and a depth of 0.1 to 0.75 mm, the minimum thickness of the doctor blade element of 0.25 mm also applying for the grooved part thereof.
Furthermore it is possible to have a provision such that adjacent to the chamfered metering surface A the blade is additionally hardened in order to increase the modulus of elasticity. In this respect the hardening should be so performed, for instance using hardening followed by annealing or laser hardening, that the hardness of the surface part of the chamfered metering surface less and increases thereunder so that the new coating blade inserted into the holder 12 is able to adapt itself by abrasion to the fine irregularities of the paper or of the applicator roll during the so-called 2~71~
running in or grinding in process as regards the engagement angle.
In order to make an even further improvement in the vibration behavior of the blade it may be best to apply bands or plates of metal, synthetic resin or rubber or combination thereof, to the blade adjacent to the point B of clamping. These additional bands or plates are preferably connected with each other and to the base material of the coating blade by rivets or screws. The selection of which pairs of the metals are to be utilized is made in accordance with measurements of the self-vibration, which are evaluated.
A diagrammatic view of this arrangement is to be seen in figure 11.
In this case the coating blade shown there firstly has a band 25 of synthetic ; rPsin bonded to it and thereon a band 26 of a further metal. The band 25 may also consist of rubber.
A more particularly useful embodiment of the invention is produced if the first or only step discontinuity ~2) is provided at a distance from the 15downstream metering edge (8) equal to 0.08 to 0.5 times the distance between this metering edge (8) and the clamped edge (C), this distance amounting to 42 to 72 mm.
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199~-0~,-2u 15:25 fl.R.L~wrence 49 99 ~92809 01 21~7~48 With re. pect to the German patent pu~lication 2,939,906 A1 it i~ tn he noted that n~ data a given.llHo~ever it apPe~rs from the drawings that no ground ch~mfer is pre~ent so that therefor~ no stif~ blade manner of oper-a~iorl is pussi~le ~o ~hich our cla.im~ are exclusively directed.
Furth~rmore it is to bs r~co~nized that the f1rst step at the tip i~
relatively long.ilAccordin~ly such blade m~y not be ~tilized in ord~r to for 1nstance apply high viscosity kni~e cnating materials at a low rate and at a hi~h Yelocity.
As regards the M~ Ringier doctor it is to be noted that th~ blade is so thin a~ the leading edge that rigidity i5 approximately lOO ttmes less than in ~he cas~ ot our thtnnest blade ran~e of 0.25 mm.ll~he method of production by electroçhemioal etching would furthenmore be uneconom1c for our st,epped blades owin~ to the small depth of re~oval.
F~ither blade would be unsuitable for our applications ~or the a~ov~
noted reasons Jn wha~ fotlows scme remarks are to be made on the hydrodynamic forces, which act on the btade during kn7~e coatin~.
The forces whleh are exerted ~y the knife coating material on the blade chamfer may be approximately calculat~d us~ng the equation for a fla~
plain bearin~.
Since the angle ~f ;nclination ~ of the chamfe~ in relation to the paper is un~nown i~ must be r~garded ~ a fi~ paramet~r and be determined empirically.
However a later geo~etrical interpretat1On is likely to b~
misleading~jIt seems that the flow condt~1Ons underneath the blade cham~er are substantiallY more complex than has been assumed in the derivation o~
this equation.~lNevertheless the e~uation is a help in approxim~tely estimating the intluence of the di~ferent parameters 6 ~ v d2 ln k 2(k-1) FL ~ ~ O ~ orce vertical to chamf~r ( k~ 2 kf l v d 4 ln k 6(k-1 ) force parallel to chamfer 1 l . ( k- 1 )h~C Ic~1 k = hl/h2 vis~o~ity ' ' ,.
.L7~ --,'0 L,~'CO n.~ w~ ~"~
2071~4~ :
h1 = wet film thickness at leading edge of the chamfar h2 ~ wet fil~ thickness at trailing edge of the cha~fer d2 = blade thickness at the tip of the blade v = veloci~y o~ paper web It wilt be ~een that the two force companents are linearly dependent on ~ and v, whereas the vertical component has a squars law dependence on the t,hickness of the blade.
Since however d is implied in h~, this dependence Uslng this equation it is possible to approxi~ately calculate the forces, which are e~erted on the blade chamfer by the kn1fe coating materisl and select a sui~able blade therefor.
In the fo110wing s~me remarks are made w;th respect to the calculation o~ ~he line of ~lexure of the blade:
The flexure of the blade may be calculated w1th a seaond order dif~rential equation:
d2y E I ~ - M(x) ~herein:
= modulus of ela~ticity I b d3/12 surface ~ament o~ inertia d = thickness of blade b = breadth of blade m(x) = moment nf flexure E characterizes the material of the blaclel I the blade geometry and M~x) the system holding the ~lade7 the points of support and the ~orces, which açt on the blade.
The maximu~ p~rniss1ble blade flexure i5 in the case of most coatin~
plant limi~ed to approxima~ely ~0~ ~o 15% of the free l~ngth of the blade (the free blade length being the distance be~ween the blade tip and the hotding means~
Accordingly maximum force at the tip of the blade is also set, if all other parameters are kept constant.
If the material o~ the blade, the blade geometry or the action o~
forces on the blsde are alt~red, the force actin~ at the blade t~p ~ay be al~èred as w~
Therefore 'itl prac~ice ~he blade is replaced and another ground cham~er or another blade t~ickness is selected in order to make a greater ch~nge in the effective thrust of the bl~de undern~ath the chamfer th~n would be possibl~ by flexure of t,he bladc alone.
It will be seen ~rom the following table 1 haw the ~exural rigidity . . ..
.
" "
L ~ ~r ~ c~
of the blade varies with the thickness o~ the blade:
- d ~mm) I ~8.33 E-13 m4) Q.1 0.2 0.3 27 0,4 64 i a~s 125 ~6 216 ~ lith knife ~oating paper blade thicknesses of 0 3 or 0.4 mm are mostly emptoyed j ~In the c~se of thic~ blades it would admittedly be posstble to produce smaller forces so t,hat in principle a larger force range ~ould be dealt with, but adiustment is not suffic;ently ~1n~.
If the flexural forces are too small in relation ~o the maximum - forcel ~he di~ferent holding sy5tems for the blade have a ~reater ;nfluenceand lead to poorer transverse sections of the co~ting action.
In g~neral the th1ckness o~ the blad~ should alwsys be so selected :~ that the knife coatin~ material may be ~pplied with a medium f1exure of the blade so that the blade i5 firmly in engagement wtth the ~ating roll while : there is sti 11 suf~icien~ play for adjustmen~ operations.
~: Assuming a change in the blade thickness fron, for inst~n~el 0.3 to: 0.4 mm the maximum possible force will be doubled.~lSince this amount ofchan~e is tGo coarse for practical appl~cat10ns7 blade6 with dif~erent chamfer 3ngles are on the ~arket so th~t, the ~ham~er 7ength may be dif~erent ~or the SamQ blade thickness.
Owing to the selection of different cham~er lengths there is also however a corresponding7y f1ner graduation ~ ~he thrust underneath the blad~ chanlf~r, ~ espite these poss~bilities of varistion kni~e coating is relatively 11mi~ed ow1ng to the dry matter content of the coa~in~ mater1al, its v1~cosity and th~ paper spee~,llThere are some fur~her factors as w~ll. -I~ blades with two or more cross ~ection~ are ~mp~oyed the chamfer length 1s no longer tied to the thickness o~ the blade.
This means that there is an add~tional fre~ parameter, which may be constderAbly ~s desired.llFor each step there is a ~ifferenti~l equation, such equat10n~ ho~ever bein~ coupled at the points of discontinuity, since the blade flexlJres are e~ual at th~ point o~ disconttnu1ty, and furthermore ~he t~ngent slopes arQ equal~
- ~ . . . ,,~ . , : . .
' ., " ', ~. ' ' ~ :
,, .: , , ,:., , " , , , ~ ' '' , ' ' ': ' ,~ ' . . ' At the p~int of the support and at the holdtng means the blade flexure is ~ero.llIt is genQr~lly impossible to pred1ct tho slope of the tangent.
The solution ~o the equations is possible with this method but it i~
not practical bec~se the ~or~ulas are extremely complex.
Therefore it is better to solv~ the equatians dtrectly numerically, for which purpose it is possible to u~e standard ~thods of numerical ma~,hema~cs as for ~nstance the formulas of Ryn~e and Kutta or finite element methods.
At the tip of the blad~ it is necessary for the bl~de angle to be calculat~d at the tangent o~ the line of flexur-e of th~ ~lade, since the blade has to be turned thro~gh th;~ angle about the tip 1n order to ensure that the b~ade chamfer keep parallel to the s~arting sett;ng.
The perpendicular and the parallel fore~ components of the blade çhamfer h~ve to be calculated with this angle and wtth the cham~er angle o~
the bl~de.
~ n the following, th~ line ~f flexure for a blade Jith three ~teps will be calc~lated by way of exa~ple using the Heavyside step ~unction methDd .
The result is then a single formula for t~s complete flexure line, the setting of the support point then being able to be freely s~lected.
This represents the great ad~antage of this metho~ of calculat1~n as compared with the above nrJtsd method.
Calc~u~lat.ion of the line o~ flexure of blade ~i.th. th~rQ stees.
~ (fi~ure 13: ~orCes~ wh~ch act at the blade) : R ~ Fl + F~ equilibrium o~ forces a F~ a) F2 e~uilibrium of torque From these two equationg we have:
.~ F2 - a Fl~(1-a~
R~ = 1 Fl~(1-a) For the torque, which causes the blade flexure, the foll~wing applies:
I~ 1s the s~rface m~ment of inertia of the first ~tep at the blade t1p.
Then:
Il ,. d3/~2 related ko the ~idth of ths blad~, d bein~ ~he blad~ thi~kn~ss.
For the second step we h3ve: I2 = m I
Far the third ~tep WQ have: I3 - n Il ' , , '" ' ' ' ',, ,,, ,, ': '~ ' ' ' ', ' ,,', ' ' , : , , ,. . . . . .
.',, ~ ~ ' , 1 a ~ . ~awr ~ r ~
E is the modulus of elastic~ty o~ the blade.
The conventional diffarential equation for the calculatian of the blade:
d2y F I ~ = M(x) has to be solved for the ~tep blade in the followin~:
d2y E 2 ~ ~ x + ~ tx-a) Ha] ~1~1txt(1~ Hx2(-l/m+l/n)]
The first ~tep ~s at the distance xl from the blade tip snd the second step at the ~istanc~ x2 from the blade t;p.
This second order differential equat;on has to be inte~rated twice:
,~ .
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':
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. .
207~
`,~
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y(x)= li(Il E~ 1 X3/6 - ~1( (l-m)/m) ) Exl (x3/6 -xl2 x/2 -:cl3~6- xl3/2) - 7~ /m ~ ) EIx2 (x3/6 - x22 x i2 - x23/6 +
x23/2) + ~ ~a (x-a)3/6 + R(l/m~l) Ka ( (x-a)3/6 ~ )2x/2 +
(xl-a)2a/2 ) + F~(-lfm - ~;/n) T3.a ~ (xa)~/6 (x2-a)2 x~2 (x2-a)2 a~2 ) ' Cl x ~ C2 ]
Ha is a jump function.
. For these jump functions the following rules of calculation -are valid: .
}ia =O i f x < a ~a =l if x ~~ a b = O if x ~ 2 Eb - 1 if X ~= b - - ~a~b = O if x < b and if a c b ~a~ib = 1 if x ~= ~ and if a c b ~ a f ~ x ) dx - xaJ f(x) dx '' Example.l:
~ ~a x2 dx = }~a ~x2 L~ a x~33 + C - ~a (:~:3-a~ 3 TC
~ , o_ , Example 2: when b ~ a ___. x x Ha ( x-a ) dx = ~b J ( x-~ ) dx ~ ( x-a ) 2 / 2 ] * C
= ~ x-a ) 2 - ~ b-a ) 2 ] i 2 +C
... .. . .
,, , , , , ; . , 20719~C~
The constants of integration Cl, C2 are calculated on the grounds of the two boundary conditlons:
y(a) = o y(l) - o Now noting the following C1 = }/1 ~ a) ~-~ Ta 3/1 ) -B]
C2 = l/(l-a) [ -A ~ a Bfl ~
A= -~1 a3/6 ~1( (1-~)/m ) Ex1 (a316 - a xl2/2 - X13~6 +
x~/2) - Fl (-l/m * 1/n) ~X2 (a3/6 a x2~/2 - ~23/6 + x23/2) ' R ( (1-m)/~) ) ~a ~-(xl-a~2 2~2 . (x1-a)2 a /2 ] -R (-1/m-l~n) ;-,a [ -(x2-a)2 a/2 ' (x2-a)2 a /2 Noting further the following inequalities:
Ea = 1 .~ Hxl = O if ~1 ~ a F~2 = if ~2 c a iF xl >= a HX2 = 1 if x2 ~= a B- -Fl 13/6 - F~m)/m ) Hxl (13/6 - 1 xl2/2 - X13/6 T
xl3/2) - Fl (-l/m~l/n) E~x2 ( 13/6 ~x2~ 23/6 ~ x23) +
R ~a ( ~l-a)/6)3 ~ R ( ~-m)/m~ :EIa t ~l-a)3/~ - (xl-a)3 1/2 .-(x1-a)2 a/2 ] + R (-1/m - l/n) Ea ~ a)316 - (22-a)2 1/2+
-~ (x2~a)2 a/2 ]
Noting thereto the following inequalities:
,, ~-1 = 1 . ~.,, Hx2 = 1 - Ha. = 1 and noting x1,x2,a ~ 1 ' , ,: ~
" . 15 ,', .
. .
' '', ' , ': : ' ' ., ~ ' .' . , ', ;: .
,: ' '', . :, ,. '. ', .. . : '' , .. . . . .
lY~Jf~ fb 1~ - ~c5 ~ . r~ . ~cl~UI c~
A The influence of the cham thru~t.
Flgure 14 indicates how f~r a g1ven ~or~e acttng perpendicularly to ~he blade chamfer there is a chan~e in t,hQ thrust chang~s as function of chamfer length.
rn this figure it i9 nece~sary to note that the x axis i5 lo~arith~ic~lly scaled, It ~ill be ~een that it is poss;ble to produce an assortment o~
bla~es with different thi~knesses and cham~er lengths such that the pressure range~ will still s~ff1cten$1y ~el1 overl~p after the repla~ement o~ the blade by a blade with a di~ferent thic~ness.
B Mod~fi atio~n i,n transverse s~rength~,the blad _ d~ _ ent on the thickness and fha ~;dth of the st~n ~ In figure 15 the surface moment of inertia for flexural rigid~ty of the blade in the transverse direction has been plotted along the x axis.
The additional thickness ~or f,he step is employed as a param~t~r ~or the family o~ curves.l~The length o~ the step is plotted alang the y axis.
It w~ll b0 seen that by having dif~erent thicknesses of the step the rigidity may be ~arted with;n very wi~e limits and that by varying the length of the step a Yery fine graduation i~ po~sible.
It ~ill be seen fr~ the two ~raphs that there are great possibilities of variation owing ~o no longar having the chamfer length depend~nt on the bla~e thickness and that by m~king a suitable selsction of the steps or grooves the transverse fl~xural ri~idi~y of the ~lade may be modi~ied ~ddttion~lly-~''' .
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.
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,
The invention relates to a doctor blade element in accordance with the preamble of claim 1. Such a doctor blade element is disclosed in the German patent publication 2,637,827 A1, and the German patent publication 2,939,906 A1 and furthermore the periodical "Der Polygraph" 9/74, pages 606 through 612.
For the coating of webs of material, more particu1arly spread coating on paper or board, it frequently occurs that a doctor blade element having the form of a strip springj a so-called spreading blade, is utilized for metering out the coating composition on the length of material or furthermore on a support or applicator roll, which at its metering end has an oblique chamfered metering surface, which is thrust by a support against the web of material or an applicator roll. In this respect the coating weight is predetermined by the equilibrium between the mechanical force at the metering surface and the hydrodynamic opposing force of the composition utilized for coating. This equilibrium may frequently be disturbed by fluctuations in the properties of the paper, of the coating composition, of the elastic cover of the support roll bearing the web of material or of the carrying system for the doctor blade element. The elasticity of the spreacling blade, which is generally manufactured of spring steel, is to a certain extent able to compensate for such interfering factors so that generally a stable equ;librium is maintained.
Should another coating weight be desired or if a parameter - such as for instance the web speed - is modified, it is then necessary for the mechanical force acting on the chamfered metering surface to be altered.
In the case of the initially mentioned German patent publication 2,637,827 A1 an attempt was made to use a very thin construction of the coating blade in the metering zone in order to avoid or substantially reduce '~the danger of streaking owing to solid particles lodged underneath the - 30 chamfered metering surface. In the case of the two other publications theintention was to obtain a more even application of the ink over long periods of time by constant dimensions and geometry of the doctor blade in the part ,~ .,.
20719~
to be subjected to wear.
In contradistinction to this the aim of the present invention is to substantially increase the strength or rigidity of the blade and its self-vibration characteristics as regards producing a high degree of smoothness of the coating and to increase the coating weight range during coating with a blade.
However it would be generally an advantage if it were possible to make greater variations in the mechanical force at the chamfered metering surface in the case of a coating blade than has hitherto been the case. It would then be possible to cope with a greater range of variation in thc weight of coating.
Therefore the object of the invention is to reduce the limitation in the range of variation of the thrust forces by a suitable design of the blade in order in this manner to be able to provide a greater range of application than has so far been the case.
This object is to be attained by the features recited in the characterizing part of claim 1.
It has been recognized by the inventor that the reason for the considerable limitation in the range of parameters during coating with a blade is because there is a connection between the thickness of the blade and the length, dependent thereon~ of the chamfered metering surface (in the case of comparable angles and as seen in the direction of travel of the web), the flexural stiffness as dependent on the thickness of the blade in the direction of travel of the paper and on the flexural stiffness of the blade in the ~25 transverse direction.
;~ For instance in the case of a blade with a constant thickness a high coating weight is tied to a low loading thrust. In this respect the blade is only tensioned and bent to a slight extent and in this working position it ~- will be weak both in this working position and also in a ~irection perpendicular thereto. The lack of transverse and longitudinal rigidity leads to an uneven distribution of the coating in the trans~erse and in the longitudinal directions.
Furthermore the blade is quite prone to self-vibration which is responsible for an inferior distribution of the material to be applied within a range of some millimeters (so-called cloudiness or step formation in the applied coating).
Conversely a low coating weight is mutatis mutandis connected with a high loading thrust and pronounced flexure o,~ the blade and thus with a greater longltudinal and transverse rigidity. Therefore the desired elastic flexure, as already mentioned, of the coating blade is less satisfactory.
". ; , , ; , ., . ,, , "; ,,, :
., . . , : ': . , . , .:
.. . . . . .
":
2:~7 ~
Fluctuations are less well compensated for than in the case of a more elastic behavior.
One feature of the invention is that significant factors including the length of chamfer of the metering edge, the flexural stiffness along the coating edge and the flexural stiffness transversely in relation to it, are no longer linked to each other and that the self-vibration of the blade may be caused to take place in a higher frequency range by having a greater^blade tension, such range no longer being responsible for an undesired effect on the quality of the coating. This is ensured in such a manner that the doctor blade elements in accordance with the invention having the form of a strip spring (as coating blades) do not have a constant thickness and in fact have two or more different cross sections.
It may be seen from the theory of elasticity that the flexural stiffness of the blade is proportional to the third power of the thickness of the blade. Therefore the flexural stiffness of the blade in the transverse direction increases in the vicinity of tip of the blade in ~he case of a blade which is thicker at the tip.
In the thinner part of the blade the flexural stiffness is accordingly substantially lower, that is to say the result is a blade which in the direction of movement behaves like a weak spring while in the transverse direction at the tip it behaves like a hard spring.
The coating effect consequently has a greater leveling action than in the case of a blade with a constant thickness: the surface of the coating becomes more even. Conversely when coating using a blade which is thinner at the tip, the loss of flexural stiffness at the tip is minimized by making the thin part of the blade very short. In addition to this it is possible for there to be a specially designed rib part directly in the transitional part between the thin and the following thicker part, such rib part substantially increasing the flexural stiffness in the transverse direction and additionally modifying self-vibration.
In this respect the coating blade in accordance with the invention may have a minimum thickness of 0.25 mm, while in the case of the known arrangement of the type initially mentioned in the case of a chamfer angle of the metering surface of at the most 20 the maximum thickness amounts to 0.17 mm and preferably 0.14 mm. Furthermore the engagement angles of the doctor blade element resembling a strip spring (i. e. a coating blade) are substantial and are equal to 25' to 45 and preferably 30' ~o 35. This angle practically constitutes the chamfer angle between the chamfered metering surface and the upstream broad side of the coating blade, i.e. the angle a.
The invention will now be described in following account of working 2~719~8 embodiments of the invention as illustrated in the drawings.
Figure 1 is a side view of a conventional coating device using a blade in accordance with the invention.
Figures 2 through 7 show embodiments of the doctor blade element resembling a strip spring in accordance with the invention.
Herein the term strip spring is used in the sense of an element, which practically constitutes a piece of thick foil of highly elastic material, such material being able to be both a metal such as hardened or alloyed steel, or a highly elastic composite synthetic resin.
In figures 2 through 7 the breadth dimension of the elements is naturally exaggerated in relation to the length of the illustrated cross sections. The cross section of the doctor blade elements is here practically illustrated in side view as the outline, as is also the case in figure 1.
' In figure 1 the support or applicator roll B bearing the web W of material is only illustrated diagrammatically. The direction of rotation is as indicated by the arrow F. The coating blade representing the strip spring doctor blade element 1 is so arranged that the chamfered metering surface A
is in engagement with the applicator roll R or, respectively, the web W of material. If this chamfered metering surface is relatively broad as in the case of figures 2, 4 and 6, the said surface should naturally be ground in - alignment with the direction of coating prior to putting into operation.Furthermore this angle a between the chamfered metering surface A and the upstream broad side of the doctor blade element which is in engagement with the applicator roll, has to be very accurately set and maintained. For this purpose it is necessary to have regulating means as are for instance described in German patent 2,913,421. An even more exact regulating device is described in the German patent application 3,937,322.
The upstream broad side of the coating blade l with the upstream metering edge 8' is in this case the laft side, as is indicated by the drips of coating composition as shown in broken lines. The web of material receives this excess of coating composition somewhere upstream from the support or applicator roll R or in the vicinity of the angle of bend of the web W of material about the applicator roll R, this not being illustrated in detail. 35 The same applies, if the coating composition ls firstly only applied to the roll.
The coating blade 1 is here clamped and held in a holder 12 with a clamping rail 13. This leads to a clamping part B on the coating blade at its end opposlte to the chamfered metering surface A. The coating blade is thrust ~ 40 upon by load1ng plates 14 in its part freely extending out of the holder, such ', .
, ' , ., .:
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.
.
' :.
2~7194~
plate 14 being in ~his case constituted by levers, adjustment in length of such levers being possible by means of screws 17 and belleville washers 18 in order to practically set the thrust acting on the coating blade. A basic adjustment is produced using the sliding plate-like carrier 15 for the loading plates 14. This way of holding for the coating blade is however only given as an example from a plurality of similar devices in the prior art. At the outlet of the coating blade from the holder there is at the end of the clamping part B a clamping line C on the end 9 (which is here the upper end) of clamping means or, respectively, a clamping rail 13.
10, Figure 2 shows a design of the strip spring doctor blade element in accordance with the invention, in the case of which the metering surface A is very broad and accordingly furthermore the so-called coating blade has a corresponding thickness. In this figure, as well as in the other figures, the - direction of movement of the web of material or the surface of the support or applicator roll is as indicated by the arrow F so that the upstream broad side of the coating blade is here in any event the left side. In all the figures the line of clamping is denoted by the letter C as shown in broken lines. In figure 2 there is a reduction in cross section at the step 3 so that towards the clamped end the coating blade becomes relatively smaller in its cross section. This blade is more particularly intended for high weights of application, in the case of which there will be a low thrust at the line L and ; correspondingly a low blade clamping effect. Owing to the great length of the chamfered metering surface A and owing to the greater thickness as far as step discontinuity 3 it is necessary for the clamping action of the blade to be considerably increased. Therefore it is possible to operate with the desired high weight of coating and simultaneously this blade will be bent to a greater extent in accordance with the greater blade tension and therefore it will be more rigid or stable.
In the converse case (see figure 3) - that is to say in the case of a very low weight of application - the chamfered metering surface A is relati-vely short and in this part the coating blade is relatively thin as far as a step discontinuity 2. The loading forces transmitted by the loading plates 14 are distributed only onto the smaller chamfered metering surface, something contributing to an increase in the loading thrust. Owing to the design in accordance with the invention with - as in this case - two different thicknesses, it is possible for the elasticity of the coating blade to be maintained within the desired range.
It is useful if the single step discontinuity 2 is placed at a dlstance from the downstream metering edge 8 equal to 0.04 to 0.5 times the distance between this metering edge 8 and the clamping edge C.
9 ~ 8 The blades in accordance with the invention make it possible to substantially increase the present day limits for coating with coating blades to achieve the following:
- a higher weight of application - a lower machine speed - a higher dry matter content and - reversed parameters or combinations thereof - better control of self-vibration of the blade.
In the embodiments of the invention illustrated in figures 4 and 5 in the case of blades for the application as in figure 2 and 3-tWQ steps 2 and 2' and, respectively, 3 and 3' in thickness are provided. Thus as shown in broken lines in figure 4 and 5 the change in cross section may also be stepless in order to approximate the change in cross section close to the computed step discontinuities as far as possible.
In figures 6 and 7 there is an overwhelmingly even change in cross section from the chamfered metering surface A as far as the clamped end of the doctor blade elements. In this respect it is a question of first terrace which always has a constant thickness in order to ensure that despite wear of the blade the length of the chamfer be constant.
It is preferred for the first step discontinuity to be at a distance from the downstream metering edge 8 equal to between 0.04 and 0.5 times the distance between this metering edge 8 and the clamped edge C and the second step discontinuity in a corresponding range between 0.06 times and 0.8 times the said distance from the first step discontinuity.
In ths case of a coating blade with a single step discontinuity it is - preferred for the thickness of the second step - taking the metering surface A as a basis - to be 5 % to 83 % of the first step and in the case of a change i in thickness in two step discontinuities - again taking the chamfered metering surface as a basis - the thickness of the second step is preferably equal to 6 % to 75 % of the thickness of the first step and the thickness of the third step is preferably equal to 25 æ to 83 % of the thickness of the second step.
It is furthermore preferable in the case of a single step ;; discontinuity for the same to be placed at a distance from the downstream'-;` meterlng edge 8 equal to between 0.04 times and 0.3 times the distance between this metering edge and the clamping line C. In this case it is then also an advantage if the thickness of the second step be between 150 and 240 %
of the first step.
In the case of there being two step discontinuities it is furthermore preferred to provide the first step discontinuity at a distance from the downstream metering edge 8 of between 0.25 times and 0.4 times the distance . ' .
'' ' . '' ' ''. ' ~' ' ' ', .' ~ ' ': ',,'' ' " :' . ~
2 ~
between this metering edge 8 and the clamping line C and to provide the second step discontinuity in a range between 0.4 times and 0.8 times the said distance. In this case it is preferred to ma~e the thickness of the second step equal to between 120 and 200 % of the thickness of the first step and the thickness of the third step equal to between 120 and 200 ~ of the thickness of the second step - in each case as measured from the chamfered metering surface A.
Furthermore in accordance with figure 8 it is possible to provide a stiffening rib 20 extending parallel to the metering edge ~ in the Form of a rail. This locally very limited increase in the cross section is intended to increase the transverse flexural stiffness at the tip of the blade and to produce a favorable change as regards the self-vibration of the blade at the tip. This rib is preferably at the most 5 mm thick and 3 mm broad and may start at a minimum distance from the matering edge 8 of 2 mm.
The rise or fall of this rib may be perpendicular or oblique and the ~; rib may be straight or curved.
- Figure 9 shows that a change in the cross section of the blade may also be produced by having grooves 21 or 22 parallel to the metering edge 8.
Additional grooves may also be provided in accordance with figure 10 20 in the case of a coating blade designed with step discontinuities. These grooves 21, 22, 23 or 24 may be rectangular, trapezoidal, rounded or triangular. It is possible for the grooves or steps to be produced by ~` removing material, preferably by grinding, milling, chemical or electrochemical milling, micro sand blasting or by similar methods, or also by laser light.
The additional grooves are preferably produced in the second step in order to provide for a further precise optimization of the longitudinal and transverse stiffness and of the self-vibration behavior of the doctor blade ; element.
In this respect the grooves preferably have a breadth of 0.1 to 05 mm and a depth of 0.1 to 0.75 mm, the minimum thickness of the doctor blade element of 0.25 mm also applying for the grooved part thereof.
Furthermore it is possible to have a provision such that adjacent to the chamfered metering surface A the blade is additionally hardened in order to increase the modulus of elasticity. In this respect the hardening should be so performed, for instance using hardening followed by annealing or laser hardening, that the hardness of the surface part of the chamfered metering surface less and increases thereunder so that the new coating blade inserted into the holder 12 is able to adapt itself by abrasion to the fine irregularities of the paper or of the applicator roll during the so-called 2~71~
running in or grinding in process as regards the engagement angle.
In order to make an even further improvement in the vibration behavior of the blade it may be best to apply bands or plates of metal, synthetic resin or rubber or combination thereof, to the blade adjacent to the point B of clamping. These additional bands or plates are preferably connected with each other and to the base material of the coating blade by rivets or screws. The selection of which pairs of the metals are to be utilized is made in accordance with measurements of the self-vibration, which are evaluated.
A diagrammatic view of this arrangement is to be seen in figure 11.
In this case the coating blade shown there firstly has a band 25 of synthetic ; rPsin bonded to it and thereon a band 26 of a further metal. The band 25 may also consist of rubber.
A more particularly useful embodiment of the invention is produced if the first or only step discontinuity ~2) is provided at a distance from the 15downstream metering edge (8) equal to 0.08 to 0.5 times the distance between this metering edge (8) and the clamped edge (C), this distance amounting to 42 to 72 mm.
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199~-0~,-2u 15:25 fl.R.L~wrence 49 99 ~92809 01 21~7~48 With re. pect to the German patent pu~lication 2,939,906 A1 it i~ tn he noted that n~ data a given.llHo~ever it apPe~rs from the drawings that no ground ch~mfer is pre~ent so that therefor~ no stif~ blade manner of oper-a~iorl is pussi~le ~o ~hich our cla.im~ are exclusively directed.
Furth~rmore it is to bs r~co~nized that the f1rst step at the tip i~
relatively long.ilAccordin~ly such blade m~y not be ~tilized in ord~r to for 1nstance apply high viscosity kni~e cnating materials at a low rate and at a hi~h Yelocity.
As regards the M~ Ringier doctor it is to be noted that th~ blade is so thin a~ the leading edge that rigidity i5 approximately lOO ttmes less than in ~he cas~ ot our thtnnest blade ran~e of 0.25 mm.ll~he method of production by electroçhemioal etching would furthenmore be uneconom1c for our st,epped blades owin~ to the small depth of re~oval.
F~ither blade would be unsuitable for our applications ~or the a~ov~
noted reasons Jn wha~ fotlows scme remarks are to be made on the hydrodynamic forces, which act on the btade during kn7~e coatin~.
The forces whleh are exerted ~y the knife coating material on the blade chamfer may be approximately calculat~d us~ng the equation for a fla~
plain bearin~.
Since the angle ~f ;nclination ~ of the chamfe~ in relation to the paper is un~nown i~ must be r~garded ~ a fi~ paramet~r and be determined empirically.
However a later geo~etrical interpretat1On is likely to b~
misleading~jIt seems that the flow condt~1Ons underneath the blade cham~er are substantiallY more complex than has been assumed in the derivation o~
this equation.~lNevertheless the e~uation is a help in approxim~tely estimating the intluence of the di~ferent parameters 6 ~ v d2 ln k 2(k-1) FL ~ ~ O ~ orce vertical to chamf~r ( k~ 2 kf l v d 4 ln k 6(k-1 ) force parallel to chamfer 1 l . ( k- 1 )h~C Ic~1 k = hl/h2 vis~o~ity ' ' ,.
.L7~ --,'0 L,~'CO n.~ w~ ~"~
2071~4~ :
h1 = wet film thickness at leading edge of the chamfar h2 ~ wet fil~ thickness at trailing edge of the cha~fer d2 = blade thickness at the tip of the blade v = veloci~y o~ paper web It wilt be ~een that the two force companents are linearly dependent on ~ and v, whereas the vertical component has a squars law dependence on the t,hickness of the blade.
Since however d is implied in h~, this dependence Uslng this equation it is possible to approxi~ately calculate the forces, which are e~erted on the blade chamfer by the kn1fe coating materisl and select a sui~able blade therefor.
In the fo110wing s~me remarks are made w;th respect to the calculation o~ ~he line of ~lexure of the blade:
The flexure of the blade may be calculated w1th a seaond order dif~rential equation:
d2y E I ~ - M(x) ~herein:
= modulus of ela~ticity I b d3/12 surface ~ament o~ inertia d = thickness of blade b = breadth of blade m(x) = moment nf flexure E characterizes the material of the blaclel I the blade geometry and M~x) the system holding the ~lade7 the points of support and the ~orces, which açt on the blade.
The maximu~ p~rniss1ble blade flexure i5 in the case of most coatin~
plant limi~ed to approxima~ely ~0~ ~o 15% of the free l~ngth of the blade (the free blade length being the distance be~ween the blade tip and the hotding means~
Accordingly maximum force at the tip of the blade is also set, if all other parameters are kept constant.
If the material o~ the blade, the blade geometry or the action o~
forces on the blsde are alt~red, the force actin~ at the blade t~p ~ay be al~èred as w~
Therefore 'itl prac~ice ~he blade is replaced and another ground cham~er or another blade t~ickness is selected in order to make a greater ch~nge in the effective thrust of the bl~de undern~ath the chamfer th~n would be possibl~ by flexure of t,he bladc alone.
It will be seen ~rom the following table 1 haw the ~exural rigidity . . ..
.
" "
L ~ ~r ~ c~
of the blade varies with the thickness o~ the blade:
- d ~mm) I ~8.33 E-13 m4) Q.1 0.2 0.3 27 0,4 64 i a~s 125 ~6 216 ~ lith knife ~oating paper blade thicknesses of 0 3 or 0.4 mm are mostly emptoyed j ~In the c~se of thic~ blades it would admittedly be posstble to produce smaller forces so t,hat in principle a larger force range ~ould be dealt with, but adiustment is not suffic;ently ~1n~.
If the flexural forces are too small in relation ~o the maximum - forcel ~he di~ferent holding sy5tems for the blade have a ~reater ;nfluenceand lead to poorer transverse sections of the co~ting action.
In g~neral the th1ckness o~ the blad~ should alwsys be so selected :~ that the knife coatin~ material may be ~pplied with a medium f1exure of the blade so that the blade i5 firmly in engagement wtth the ~ating roll while : there is sti 11 suf~icien~ play for adjustmen~ operations.
~: Assuming a change in the blade thickness fron, for inst~n~el 0.3 to: 0.4 mm the maximum possible force will be doubled.~lSince this amount ofchan~e is tGo coarse for practical appl~cat10ns7 blade6 with dif~erent chamfer 3ngles are on the ~arket so th~t, the ~ham~er 7ength may be dif~erent ~or the SamQ blade thickness.
Owing to the selection of different cham~er lengths there is also however a corresponding7y f1ner graduation ~ ~he thrust underneath the blad~ chanlf~r, ~ espite these poss~bilities of varistion kni~e coating is relatively 11mi~ed ow1ng to the dry matter content of the coa~in~ mater1al, its v1~cosity and th~ paper spee~,llThere are some fur~her factors as w~ll. -I~ blades with two or more cross ~ection~ are ~mp~oyed the chamfer length 1s no longer tied to the thickness o~ the blade.
This means that there is an add~tional fre~ parameter, which may be constderAbly ~s desired.llFor each step there is a ~ifferenti~l equation, such equat10n~ ho~ever bein~ coupled at the points of discontinuity, since the blade flexlJres are e~ual at th~ point o~ disconttnu1ty, and furthermore ~he t~ngent slopes arQ equal~
- ~ . . . ,,~ . , : . .
' ., " ', ~. ' ' ~ :
,, .: , , ,:., , " , , , ~ ' '' , ' ' ': ' ,~ ' . . ' At the p~int of the support and at the holdtng means the blade flexure is ~ero.llIt is genQr~lly impossible to pred1ct tho slope of the tangent.
The solution ~o the equations is possible with this method but it i~
not practical bec~se the ~or~ulas are extremely complex.
Therefore it is better to solv~ the equatians dtrectly numerically, for which purpose it is possible to u~e standard ~thods of numerical ma~,hema~cs as for ~nstance the formulas of Ryn~e and Kutta or finite element methods.
At the tip of the blad~ it is necessary for the bl~de angle to be calculat~d at the tangent o~ the line of flexur-e of th~ ~lade, since the blade has to be turned thro~gh th;~ angle about the tip 1n order to ensure that the b~ade chamfer keep parallel to the s~arting sett;ng.
The perpendicular and the parallel fore~ components of the blade çhamfer h~ve to be calculated with this angle and wtth the cham~er angle o~
the bl~de.
~ n the following, th~ line ~f flexure for a blade Jith three ~teps will be calc~lated by way of exa~ple using the Heavyside step ~unction methDd .
The result is then a single formula for t~s complete flexure line, the setting of the support point then being able to be freely s~lected.
This represents the great ad~antage of this metho~ of calculat1~n as compared with the above nrJtsd method.
Calc~u~lat.ion of the line o~ flexure of blade ~i.th. th~rQ stees.
~ (fi~ure 13: ~orCes~ wh~ch act at the blade) : R ~ Fl + F~ equilibrium o~ forces a F~ a) F2 e~uilibrium of torque From these two equationg we have:
.~ F2 - a Fl~(1-a~
R~ = 1 Fl~(1-a) For the torque, which causes the blade flexure, the foll~wing applies:
I~ 1s the s~rface m~ment of inertia of the first ~tep at the blade t1p.
Then:
Il ,. d3/~2 related ko the ~idth of ths blad~, d bein~ ~he blad~ thi~kn~ss.
For the second step we h3ve: I2 = m I
Far the third ~tep WQ have: I3 - n Il ' , , '" ' ' ' ',, ,,, ,, ': '~ ' ' ' ', ' ,,', ' ' , : , , ,. . . . . .
.',, ~ ~ ' , 1 a ~ . ~awr ~ r ~
E is the modulus of elastic~ty o~ the blade.
The conventional diffarential equation for the calculatian of the blade:
d2y F I ~ = M(x) has to be solved for the ~tep blade in the followin~:
d2y E 2 ~ ~ x + ~ tx-a) Ha] ~1~1txt(1~ Hx2(-l/m+l/n)]
The first ~tep ~s at the distance xl from the blade tip snd the second step at the ~istanc~ x2 from the blade t;p.
This second order differential equat;on has to be inte~rated twice:
,~ .
~ .
':
, ~ , . ; , ,, ' , ,, , ' . , .
. .
207~
`,~
.,~. ., ~
-- .
. .
: ':
y(x)= li(Il E~ 1 X3/6 - ~1( (l-m)/m) ) Exl (x3/6 -xl2 x/2 -:cl3~6- xl3/2) - 7~ /m ~ ) EIx2 (x3/6 - x22 x i2 - x23/6 +
x23/2) + ~ ~a (x-a)3/6 + R(l/m~l) Ka ( (x-a)3/6 ~ )2x/2 +
(xl-a)2a/2 ) + F~(-lfm - ~;/n) T3.a ~ (xa)~/6 (x2-a)2 x~2 (x2-a)2 a~2 ) ' Cl x ~ C2 ]
Ha is a jump function.
. For these jump functions the following rules of calculation -are valid: .
}ia =O i f x < a ~a =l if x ~~ a b = O if x ~ 2 Eb - 1 if X ~= b - - ~a~b = O if x < b and if a c b ~a~ib = 1 if x ~= ~ and if a c b ~ a f ~ x ) dx - xaJ f(x) dx '' Example.l:
~ ~a x2 dx = }~a ~x2 L~ a x~33 + C - ~a (:~:3-a~ 3 TC
~ , o_ , Example 2: when b ~ a ___. x x Ha ( x-a ) dx = ~b J ( x-~ ) dx ~ ( x-a ) 2 / 2 ] * C
= ~ x-a ) 2 - ~ b-a ) 2 ] i 2 +C
... .. . .
,, , , , , ; . , 20719~C~
The constants of integration Cl, C2 are calculated on the grounds of the two boundary conditlons:
y(a) = o y(l) - o Now noting the following C1 = }/1 ~ a) ~-~ Ta 3/1 ) -B]
C2 = l/(l-a) [ -A ~ a Bfl ~
A= -~1 a3/6 ~1( (1-~)/m ) Ex1 (a316 - a xl2/2 - X13~6 +
x~/2) - Fl (-l/m * 1/n) ~X2 (a3/6 a x2~/2 - ~23/6 + x23/2) ' R ( (1-m)/~) ) ~a ~-(xl-a~2 2~2 . (x1-a)2 a /2 ] -R (-1/m-l~n) ;-,a [ -(x2-a)2 a/2 ' (x2-a)2 a /2 Noting further the following inequalities:
Ea = 1 .~ Hxl = O if ~1 ~ a F~2 = if ~2 c a iF xl >= a HX2 = 1 if x2 ~= a B- -Fl 13/6 - F~m)/m ) Hxl (13/6 - 1 xl2/2 - X13/6 T
xl3/2) - Fl (-l/m~l/n) E~x2 ( 13/6 ~x2~ 23/6 ~ x23) +
R ~a ( ~l-a)/6)3 ~ R ( ~-m)/m~ :EIa t ~l-a)3/~ - (xl-a)3 1/2 .-(x1-a)2 a/2 ] + R (-1/m - l/n) Ea ~ a)316 - (22-a)2 1/2+
-~ (x2~a)2 a/2 ]
Noting thereto the following inequalities:
,, ~-1 = 1 . ~.,, Hx2 = 1 - Ha. = 1 and noting x1,x2,a ~ 1 ' , ,: ~
" . 15 ,', .
. .
' '', ' , ': : ' ' ., ~ ' .' . , ', ;: .
,: ' '', . :, ,. '. ', .. . : '' , .. . . . .
lY~Jf~ fb 1~ - ~c5 ~ . r~ . ~cl~UI c~
A The influence of the cham thru~t.
Flgure 14 indicates how f~r a g1ven ~or~e acttng perpendicularly to ~he blade chamfer there is a chan~e in t,hQ thrust chang~s as function of chamfer length.
rn this figure it i9 nece~sary to note that the x axis i5 lo~arith~ic~lly scaled, It ~ill be ~een that it is poss;ble to produce an assortment o~
bla~es with different thi~knesses and cham~er lengths such that the pressure range~ will still s~ff1cten$1y ~el1 overl~p after the repla~ement o~ the blade by a blade with a di~ferent thic~ness.
B Mod~fi atio~n i,n transverse s~rength~,the blad _ d~ _ ent on the thickness and fha ~;dth of the st~n ~ In figure 15 the surface moment of inertia for flexural rigid~ty of the blade in the transverse direction has been plotted along the x axis.
The additional thickness ~or f,he step is employed as a param~t~r ~or the family o~ curves.l~The length o~ the step is plotted alang the y axis.
It w~ll b0 seen that by having dif~erent thicknesses of the step the rigidity may be ~arted with;n very wi~e limits and that by varying the length of the step a Yery fine graduation i~ po~sible.
It ~ill be seen fr~ the two ~raphs that there are great possibilities of variation owing ~o no longar having the chamfer length depend~nt on the bla~e thickness and that by m~king a suitable selsction of the steps or grooves the transverse fl~xural ri~idi~y of the ~lade may be modi~ied ~ddttion~lly-~''' .
, , .
., 1~
.
:~: .. . ' . .; ' .
' '' - ' .: . : ' , . .
., ' ' . ~ . ': .
,
Claims (24)
1 A strip spring-like doctor blade element (1, 1'; 11 and 11') adapted to be clamped at its one end in a holder (12), with an obliquely formed chamfered metering surface (A) for the coating or metering of a composition onto a web (W) of material or a roll continuously moving at a constant rate, in the case of which at least one modification in the cross section is present along at least one line or edge parallel to its metering edge or chamfered metering surface (A), characterized in that a change in cross section is provided between the clamped end (B) and the chamfered metering surface (A) of the doctor blade element continuously or in a suitable number of steps (2, 2'; 3 and 3') the chamfered metering surface (A) forming an angle of at least 25° on the broad side of the doctor blade element on the downstream side thereof or accordingly less than 155° on the upstream side thereof.
2 The doctor blade element as claimed in claim 1, characterized in that the minimum thickness of the doctor blade element (1, 1'; 11 and 11') is equal to at least 0.25 mm and its maximum thickness is equal to 5 mm at the chamfered metering surface (A) and 20 mm in the clamped part (B) of the doctor blade element.
3 The doctor blade element as claimed in claim 1 or in claim 2, characterized in that the change in thickness is in at the most two steps (2, 2'; 3 and 3') in a terraced structure outside of the clamped part (B) of the doctor blade element (1, 1'; 11 and 11').
4 The doctor blade element as claimed in any one of the preceding claims 1 through 3, characterized in that for a low weight of coating the cross section through the steps or through the change in thickness is generally narrowest adjacent to the chamfered metering surface (A).
5 The doctor blade element as claimed in any one of the preceding claims 1 through 3, characterized in that for a high weight of coating the cross section through the steps or through the change in thickness is generally broadest adjacent to the chamfered metering surface (A).
6 The doctor blade element as claimed in any one of the preceding claims 1 through 5, characterized in that the steps constituting changes in the thickness are provided on both sides and preferably on the downstream side of the doctor blade element (1 and 1').
7 The doctor blade element as claimed in any one of the preceding claims 1 through 6, characterized in that the steps constituting the change in thickness are provided outside the clamped part (B) of the doctor blade element.
8 The doctor blade element as claimed in any one of the preceding claims 1, 2 and 7, characterized in that the changes in cross section of the doctor blade element are arranged in the form of grooves, which extend transversely in relation to the direction of movement in the doctor blade element.
9 The doctor blade element as claimed in either of the preceding claims 1 to 7, characterized in that the grooves are provided on one or both sides and preferably however on the side facing in the downstream direction.
10 The doctor blade element as claimed in any one of the preceding claims 1, 2, 4, 5, 7 and 9, characterized in that the grooves (21 to 24) are 0.1 mm to 0.5 broad and 0.1 mm to 0.75 mm deep, the minimum thickness of the doctor blade element of 0.25 mm also obtaining in the grooved part thereof.
11 The doctor blade element as claimed in any one of the preceding claims 1 through 3 and 5 through 7, characterized in that a single step discontinuity (2) is provided at a distance from the downstream metering edge (8) equal to 0.04 times to 0.5 times the distance between this metering edge (8) and the clamped edge (C).
12 The doctor blade element as claimed in any one of the preceding claims 1 through 3 and 5 through 7, characterized in that the first step discontinuity is arranged at a distance from the downstream metering edge (8) equal to 0.04 times to 0.5 times the distance between this metering edge (8) and the clamped edge (C) and the second step discontinuity in a corresponding range between 0.06 times and 0.8 times the said distance,
13 The doctor blade element as claimed in any one of claims 1 through 3, 5 through 7 and 11, characterized in that the thickness of the first step of the second step is equal to 5 % to 83 % of the thickness of the first step.
14 The doctor blade element as claimed in any one of claims 1 through 3, 5 through 7, 11 and 12, characterized in that the thickness of the second step is equal between 6 % and 75 % of the thickness of the first step and in that the thickness of the third step is equal to 25 % to 83 % of the thickness of the second step.
15 The doctor blade element as claimed in any one of claims 1, 2, 4, 6 and 7, characterized in that a single step discontinuity is provided at a distance from the downstream metering edge (8) of 0.04 times to 0.3 times the distance between this metering edge (8) and the clamping line (C).
16 The doctor blade element as claimed in any one of claims 1, 2, 4, 6 and 7, characterized by the presence of two step discontinuities, the first step discontinuity being at a distance from the downstream metering edge (8) of 0.25 times to 0.4 times the distance between this metering edge (8) and the clamping line (C) and the second step discontinuity in a range of 0.06 to 0.8 times the said distance from the first step discontinuity (2').
17 The doctor blade element as claimed in any one of claims 1, 2, 4, 6, 7 and 15, characterized in that the thickness of the second step is equal to 150 % to 240 % that of the first step.
18 The doctor blade element as claimed in any one of claims 1, 2, 4, 6, 7 and 16, characterized in that the thickness of the second step is equal to 120 % to 200 % of that of the first step and in that the thickness of the third step is equal to 120 % to 200 % of that of the second step.
19 The doctor blade element as claimed in any one of claims 1, 2, 4, 6, 7 and 15 through 18, characterized in that a rail-like additional stiffening rib is arranged following the first step, such rib having a maximum thickness of 5 mm and a maximum breadth of 3 mm and starts at a minimum distance of 2 mm from the metering edge (8).
20 The doctor blade element as claimed in any one of the preceding claims 1 through 19, characterized in that grooves are provided in the steps and more preferably in the second step, the grooves (21 through 24) being 0.1 to 0.5 mm broad and 0.1 to 0.75 mm deep and the minimum thickness of the doctor blade element of 0.25 mm also applies for the grooved part thereof.
21 The doctor blade element as claimed in any one of the preceding claims 1 through 20, characterized in that the first or only step discontinuity (2) is provided at a distance from the downstream metering edge (8) equal to 0.08 times to 0.5 times the distance between this metering edge (8) and the clamped edge (C), such distance being equal to 42 to 72 mm.
22 The doctor blade element as claimed in any one of the preceding claims 1 through 21 characterized in that its hardness of the surface part of the chambered metering area A is less and increases under it.
23 The doctor blade element at claimed in any one of the preceding claims 1 through 22, characterized in that clamping bands or plates of metal synthetic resin or rubber or a combination thereof are applied to the coating blade in addition to give an overall thickness of 20 mm, such bands or plates being arranged in the clamped part of the blade.
24 The doctor blade element as claimed in claim 23, characterized in that the additional parts and the doctor blade element are connected together mechanically, preferably by rivets, screws or are bonded together or are connected together by combination of both methods.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4033481.3 | 1990-10-20 | ||
| DE4033481A DE4033481A1 (en) | 1990-10-20 | 1990-10-20 | Squeegee element for coating webs or similar |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2071948A1 true CA2071948A1 (en) | 1992-04-21 |
Family
ID=6416768
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002071948A Abandoned CA2071948A1 (en) | 1990-10-20 | 1991-10-19 | Doctor blade for use in coating continuous strips of material or similar substrates |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0506911B1 (en) |
| JP (1) | JPH05504511A (en) |
| AT (1) | ATE128385T1 (en) |
| CA (1) | CA2071948A1 (en) |
| DE (2) | DE4033481A1 (en) |
| FI (1) | FI107375B (en) |
| WO (1) | WO1992006796A1 (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19508298C2 (en) * | 1995-03-09 | 1999-05-06 | Joh Clouth Fa | Scraper device for a roller |
| DE29611194U1 (en) * | 1996-06-26 | 1996-09-05 | Voith Sulzer Papiermaschinen GmbH, 89522 Heidenheim | Fastening device |
| DE29619507U1 (en) * | 1996-11-09 | 1997-01-23 | Voith Sulzer Papiermaschinen GmbH, 89522 Heidenheim | Doctor blade |
| US5846325A (en) * | 1997-02-25 | 1998-12-08 | The Mead Corporation | Coating blade and method of using the same |
| DE19740952A1 (en) * | 1997-09-17 | 1999-03-18 | Voith Sulzer Papiermasch Gmbh | Web coating applicator |
| DE19748684A1 (en) * | 1997-11-04 | 1999-05-06 | Voith Sulzer Papiertech Patent | Moving web coating applicator for coating paper or cardboard |
| DE19812929A1 (en) * | 1998-03-24 | 1999-09-30 | Voith Sulzer Papiertech Patent | Machine continuously metering and leveling coating of fluid or viscous material |
| DE102005002637A1 (en) * | 2005-01-20 | 2006-07-27 | Voith Paper Patent Gmbh | scraper blade |
| DE102006018525A1 (en) * | 2006-04-21 | 2007-10-25 | Man Roland Druckmaschinen Ag | Squeegee device for color deck washing, has elastic squeegee cutter forming doctor blade, and supported with respect to color deck roller, so that blade is brought into mechanical contact with surface of color deck roller for cleaning |
| JP2014069359A (en) * | 2012-09-27 | 2014-04-21 | Dainippon Printing Co Ltd | Doctor blade |
| EP3936339A1 (en) | 2020-07-10 | 2022-01-12 | Daetwyler Swisstec Ag | Laser machined squeegee |
| JP7380538B2 (en) * | 2020-12-15 | 2023-11-15 | Ｊｆｅスチール株式会社 | Bath roll polishing blade, polishing equipment and plating equipment |
| DE102021103315A1 (en) | 2021-02-12 | 2022-08-18 | TKM Meyer GmbH | squeegee |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3908590A (en) * | 1968-02-08 | 1975-09-30 | Ethyl Corp | Opposed blade coater |
| BE795033A (en) * | 1972-02-09 | 1973-05-29 | Daetwyler & Co M | SQUEEGEE FOR HELIOGRAPHING MACHINES |
| CH550664A (en) * | 1973-02-27 | 1974-06-28 | Buser Ag Maschf Fritz | ROTARY FILM PRINTING MACHINE. |
| IT999822B (en) * | 1973-11-26 | 1976-03-10 | Belcit Italia Spa | DEVICE FOR ADJUSTING THE THICKNESS OF THE COATING SUSPENSION LAYER DEPOSED ON A CONTINUOUS PAPER BELT IN A COATING MACHINE |
| SE424511B (en) * | 1975-08-26 | 1982-07-26 | Inventing Ab | SET AND DEVICE TO COAT A CURRENT COAT - PREFERRED PAPER |
| SE424510B (en) * | 1975-08-26 | 1982-07-26 | Inventing Ab | SET AND DEVICE FOR DOUBLE SIDE COATING OF A CURRENT COAT |
| DE2823603C2 (en) * | 1978-05-30 | 1982-02-25 | Max Dätwyler & Co., Bleienbach, Bern | Packaging for at least one squeegee |
| DE2939906A1 (en) * | 1979-10-02 | 1981-04-23 | Saueressig Gmbh, 4422 Ahaus | Rotary screen printing machine doctor blade - has large portion of profiled cross=section protruding from holder |
| SE437683B (en) * | 1982-10-13 | 1985-03-11 | Inventing Ab | CREATE OR SHELL - MATERIAL AGAINST THE ROLL - BY EXV |
| US4780336A (en) * | 1987-04-06 | 1988-10-25 | Consolidated Papers, Inc. | Doctor blade for paper coater |
-
1990
- 1990-10-20 DE DE4033481A patent/DE4033481A1/en not_active Ceased
-
1991
- 1991-10-19 JP JP3516869A patent/JPH05504511A/en active Pending
- 1991-10-19 WO PCT/EP1991/001985 patent/WO1992006796A1/en not_active Ceased
- 1991-10-19 EP EP91918114A patent/EP0506911B1/en not_active Expired - Lifetime
- 1991-10-19 AT AT91918114T patent/ATE128385T1/en not_active IP Right Cessation
- 1991-10-19 DE DE59106595T patent/DE59106595D1/en not_active Expired - Fee Related
- 1991-10-19 CA CA002071948A patent/CA2071948A1/en not_active Abandoned
-
1992
- 1992-06-17 FI FI922813A patent/FI107375B/en active
Also Published As
| Publication number | Publication date |
|---|---|
| ATE128385T1 (en) | 1995-10-15 |
| DE59106595D1 (en) | 1995-11-02 |
| WO1992006796A1 (en) | 1992-04-30 |
| FI107375B (en) | 2001-07-31 |
| FI922813A0 (en) | 1992-06-17 |
| FI922813L (en) | 1992-06-17 |
| EP0506911B1 (en) | 1995-09-27 |
| EP0506911A1 (en) | 1992-10-07 |
| DE4033481A1 (en) | 1992-04-23 |
| JPH05504511A (en) | 1993-07-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |