WO2007079731A2

WO2007079731A2 - Creping blade, method for producing a creping blade and use of a creping blade

Info

Publication number: WO2007079731A2
Application number: PCT/DE2007/000039
Authority: WO
Inventors: Martin Bauer; Philippe Mattern
Original assignee: Martin Bauer; Philippe Mattern
Priority date: 2006-01-09
Filing date: 2007-01-09
Publication date: 2007-07-19
Also published as: DE112007000595A5; DE102006001336A1; WO2007079731A3; EP1976685A2

Abstract

The invention relates to a creping blade (1) which is to be placed with one working edge (2) at a drying cylinder (3) in order to detach and crep a paper web (4) rotating on a drying cylinder (3) with a profiled metal body (5). The working edge (2) is formed by a wear resistant hard material located at the region (3) of the creping blade which is facing the drying cylinder (3). The invention is characterized in that the hard material cover (7) extends in the region of the stopping area of the blade tip from the working edge (2) into the stopping area (8), the depth of the hard material cover (10) being greater or equal to 300 micrometers while the entire depth of the stopping area ranges from 800 to about 1200 micrometers.

Description

Creping doctor, method of making a creping doctor and using a creping doctor

The invention relates to a creping doctor, which is to be set with a working edge to a drying cylinder to detach a paper web circulating on the drying cylinder and creping, with a metal profile body, wherein the working edge formed by a wear-resistant hard material on the drying cylinder facing portion of the creping doctor is a method of making a creping doctor and using a creping doctor.

The creping doctor has a working edge to be applied to the drying cylinder, which maintains contact with the cylinder surface and thus detaches and partially stops the paper web circulating on the drying cylinder to form a porous paper product (tissue). The paper web moves at speeds of up to 1,200 to 1,900 m / min. The drying cylinder rotates against the working edge of the creping doctor from above and the paper layer detached and creped by the creping doctor is then wound up by means of a retractor.

The creping is done by bouncing and partially stopping the detached paper web onto a run-on surface introduced at the doctor tip of the creping doctor. Due to the strong forces acting on the scraper in the region of the working edge and the ramp surface, these areas are subject to heavy wear, which only allows a short service life of the scraper or leads to a rapidly decreasing paper quality. The object is to provide a creping scraper which has a low wear with a long-lasting good quality of the creped paper.

The object is achieved by a creping doctor with the features presented in the introduction, wherein the hard material cover extends in the area of the shoulder surface of the doctor blade from the working edge over a Hartmaterialabdeckungs- depth of> = about 300 micrometers into the ramp surface in a running surface total depth of about 800 microns to about 1200 microns.

The creping scraper is protected by the hard material cover against wear and rapid wear by the incoming paper, the production is simplified because only a portion of the ramp surface is covered. The hard material cover securely adheres to the metal profile body, since the hard material cover extending from the working edge, in particular with a greater thickness extends into the ramp surface. As a result, the compound of hard material cover and metal profile body also resists any stresses on the creping doctor, in particular bending loads without material peeling off.

Further, the object is achieved by a creping doctor with the features shown in the introduction, wherein the ramp surface has a side facing away from the working edge and opposite a front, working edge near Auflaufflächeπbereich inclined end surface region.

In particular, by the respectively set inclination of the end surface region and a correspondingly established beginning of the inclined end surface region, it is possible to make an adjustment of the thickness and softness of the crepe material adapted to the respectively required tissue quality. The depth of the front ramp area can be adjusted well by the beginning of the inclined end face area and can also be made with a very small depth, whereby the stability of the creping doctor as a whole is not impaired. Parameters which continue to influence the quality of the finish include, among others, the moisture content of the paper web on the drying cylinder, as well as the properties of the paper web. ten of the adhesive, with which the paper web is held on the drying cylinder, the angle of the creping doctor to the cylinder and the insertion depths of the creping doctor in relation to the cylinder.

On the one hand, due to the protection provided by the hard material layer according to the invention, the incoming paper can strike the ramp surface for a long time without damaging it and, at the same time, the paper is released by the early withdrawal from the ramp surface in the angled end surface area with regard to its thickness and softness easier to adjust. The invention avoids an increase in the volume of the tissue and a decreasing softness. With the reduction of wear, the term is significantly extended.

It is advantageous if the hard material cover is formed substantially to the end of the ramp surface.

A good stability of the cover and sufficient protection of the scraper is given when the hard material cover is formed on the ramp surface to about 500 microns depth.

It is advantageous if the hard material cover increases from a scraper base area to the ramp surface in the profile cross section. As a result of the course according to the invention, the hard material covering on the one hand has good stability, since the cover has a large thickness, in particular on the heavily loaded ramp surface.

An easily manufactured and at the same time very durable coating is when the profile cross section of the hard material cover is triangular.

A further increase in material thickness and, at the same time, stability in the area of the run-on surface is present when the profile cross-section of the hard-material covering has a growing pitch. A secure interception arrangement for transverse and longitudinal peak loads is present when the profile cross section of the hard material cover is continuously increasing.

The manufacture, in particular, of the polished section in the area of the metal profile body is facilitated if the profile cross section of the hard material cover is constant in sections, with the respectively following section rising more strongly.

An individual adaptation to the loads of the hard material cover can be made easily if the profile cross section of the hard material cover has different, pre-inserted angle ranges.

A very good abrasion protection is when the hard material cover has a ceramic material, in particular a metal oxide, silicide, boride, nitride or mixtures thereof, or a metallic hard alloy, or mixtures thereof.

It is advantageous if the hard material cover has aluminum oxide, chromium oxide, zirconium oxide, tungsten carbide, chromium carbide, zirconium carbide, tantalum carbide or titanium carbide or mixtures thereof.

A very stable bond between the metal profile body and the hard material cover and the Hartmaterialabdeckung in itself, when the hard material cover thermally sprayed material, in particular by physical vapor deposition (PVD), chemical vapor deposition (CVD) or high velocity flame spraying (HVOF) applied , In addition, the thickness of the hard material cover in this way is easily adjustable and allows an individualized production of crepe scrapers according to different requirements.

It is advantageous if the end surface area is inclined relative to the front ramp surface area by a differential tilt angle, the amount of which is preferably between about 4 ° and about 80 °, more preferably between about 5 ° and about 20 °, further preferably about 10 ° to about 15 °. The inclination is specially selected according to the requirements of the tissue properties. Due to the two angles of inclination on the surface, the paper can not jump as high.

It is advantageous if the inclination of the end face region with respect to the front run-on surface region is low with a difference inclination angle, in particular between about 5 ° to about 15 °. The flatter the end surface area, the more fine control of the tissue properties is possible, for example with respect to the amplitude of the tissue tissue and the withdrawal point at which the tissue web is withdrawn from the creping doctor by the downstream retractors. In particular, the angle determines how far the tissue can still impact on the inclined end surface area, which is the more frequent the smaller the difference tilt angle is. Furthermore, an influence of the angle of inclination of the edge of the working surface is given. An important parameter also provides the beginning of the inclined ramp surface area, the ramp surface transition area, as this determines the size of the front ramp surface. The smaller the casserole area used for hitting the tissue, the softer the tissue becomes, especially with increased volume.

It is advantageous if the inclination of the end surface area with respect to the front shoulder surface area is steep with a difference inclination angle, in particular between approximately 30 ° to approximately 50 °. The steeper the end surface area, the sooner the tissue is pulled off. For the paper crepe essentially only the front ramp surface area is used. An inclination of 25 ° to 40 ° results in thick wrinkles in the tissue.

It is advantageous if the working edge near the ramp surface area is inclined with an inclination angle, which is particularly negative, with an amount of about 0 ° to 25 °, in particular if the hard material cover is made of ceramic, 0 ° to 40 °, in particular if the hard material cover is a hard metal is, in particular 5 ° to 10 °, or in particular is positive, in particular with an amount of about 0 ° to about 40 °. The ramp surface angle is for the paper quality or paper create important, the exact adjustability in terms of softness and volume depends on each product. A positive angle of inclination makes the tissue more compressed and harder, while at a negative angle of inclination the tissue softens. The angle of inclination is determined relative to the horizontal, counterclockwise mathematically positive, wherein the horizontal is related to a running from the base to the ramp surface longitudinal axis of the creping doctor.

It is advantageous if the depth of the front, working edge near ramp surface area up to a ramp surface transition region is up to about 600 to about 800 microns. By this dimension, the front ramp surface area is not formed too deep on the one hand to reliably deliver soft tissue and on the other hand, the creping blade is stable.

Very good abrasion resistance is achieved when the end surface area essentially begins with the completion of the hard material cover on the ramp surface.

It is advantageous if the end surface area begins after about 45% of the run-flat total depth, in particular if the run-flat surface has a depth of about 500 micrometers, in particular if the total metal profile body depth is about 1200 micrometers, the hard material coverage depth being in particular about 250 micrometers. This distribution of the surfaces achieves, on the one hand, a soft tissue and, on the other hand, great stability of the creping doctor.

It is advantageous if the end surface area begins in a later ramp surface transition area when the difference tilt angle becomes greater.

A good elasticity, stability and machinability is when metal profile body of hot or cold rolled steel, in particular spring steel exists. The steel is preferably carbon steel. To make the creping doctor, the steel is ground flat and straightened, as the creping blades have a large cross-section. have elongation, for example, 3-4 m, corresponding to the length of the drying cylinder.

It is advantageous if a surface facing the drying cylinder is introduced in the hard material cover at a predetermined angle.

In particular, it is advantageous if the angle is between about 5 ° and about 15 °, in particular about 6 ° to about 12 °, in particular about 7 ° in order to achieve a better adaptation of the surface to the moving cylinder.

A strong limitation of the dusting during creping is given when the surface has a height of about 0.2 mm to about 4 mm, in particular about 2.3 mm to about 3 mm. The dust is partly removed behind the scraper. The remaining dust is fine-grained, so that no larger agglomerations form and the smaller particles thus run behind the scraper and can be derived. In addition, the dust is not placed on the tissue product and thus improves the quality. The surface described with the proposed height can also be used in otherwise conventional scrapers of the prior art with the corresponding advantages listed.

The object is likewise achieved by a method for producing a creping doctor, in particular according to one of claims 1 to 25, wherein the end surface region of the metal profile body for producing an angled surface and / or the surface of the hard material cover mechanically ablate, in particular is to be abraded, in particular before the hard material cover is applied.

The object is also achieved by using a creping doctor according to one of claims 1 to 25, produced in particular by a process according to claim 26, for the production of crepe paper, by the creping doctor having a working edge to a drying cylinder with a circulating paper web. is set and the paper web runs on the ramp surface of the creping doctor, creped and then removed from this.

Further features and advantages of the invention will become apparent from the claims and the following description in which embodiments of the subject invention in conjunction with the drawings are explained in more detail.

Show it:

1 creping doctor with inclined end face, attached to a drying cylinder,

2 creping doctor with inclined end surface,

Fig. 3 creping doctor with inclined end face and

Fig. 4 creping doctor.

Fig. 1 shows a part of a cross section through a creping blade 1, which is attached to a working edge 2 to a drying cylinder 3 with an applied, moist paper web, that the drying cylinder 3, the working edge 2 of the creping doctor 1 turned from above and through the creping doctor 1, the paper layer 4 detached, creped and then rewound using a device, not shown.

The creping doctor 1 has a metal profile body 5, which consists in particular of a hot or cold rolled steel and has a width adapted to the cylinder expansion. In a region facing the drying cylinder 6, a hard material cover 7 is applied to the metal profile body 5. The creping is done by the bouncing and partial stopping of the detached paper web 4 on an introduced at a scraper tip 9 of the creping doctor 1 ramp surface 8. The thus generated waveform in the paper obtained by the structure of the ramp surface 8 specific properties such as softness and volume, said by the inventive Formation of the ramp surface 8, the material properties can be adjusted. The hard material applied in a predetermined hard material coverage depth 10 protects the ramp surface 8 from premature wear by the high speed impacting paper layers. At the front metal profile body region, two angular regions 11, 12 are introduced with a stronger and a weaker gradient, so that the hard material covering applied thereon has a profile cross-section 13 becoming stronger from a doctor base 20 to the shoulder surface 8. This will increase the stability of the hard material cover

7 increased and secured even when bending the creping doctor 1 permanent coating.

FIG. 2 shows part of a cross-section of a creping doctor 1. The creping doctor has a metal profile body depth 16 and a running surface total depth 17. The casserole surface 8 of the creping doctor 1 has a front ramp surface region 14 with a low inclination 22 and an end surface region 18 which is sharply inclined thereto. The difference of the inclinations of the two surfaces is measured by a difference tilt angle 15. The front ramp surface 14 is up to a termination 21 with a hard material coverage depth 10 from the hard material cover

8 covered. The hard material cover 7 has an angle 11 in the contact region to the metal profile body. The profile cross section 13 of the hard material cover 7 rises continuously from a scraper base 20 to the ramp surface 8.

The strong inclination of the end surface region 18 of the ramp surface 8 results in the creped tissue being drawn off at an early time, in particular already at a depth 24 corresponding to the front ramp surface, at the ramp surface transition region 23 between the two ramp surface regions. As a result, on the one hand a small ramp surface offered, whereby very soft tissue can be produced and on the other hand, a stable creping scraper due to large metal body profile depth 16th

FIG. 3 shows a creping doctor 1 with an end face 18 inclined slightly opposite the front ramp surface 14. Due to the low inclination of the end surface 18, the ramp surface 8 is still applied beyond the ramp surface transition region 23 of the paper web. The tissue receives adjustable softness and adjustable volume. A surface 27 on the working edge 2 can be made with a smaller or a larger height 26. A strong limitation of the dusting during creping is given when the surface 27 has a height 26 of about 1.5 mm to about 4 mm, in particular about 2.3 mm to about 3 mm. This is true for all scrapers and is not limited to the example given.

FIG. 4 shows a creping doctor 1 with a front ramp surface area inclined from the drying cylinder with a negative inclination angle 22, which in this case coincides with the ramp surface with a ramp surface total depth 17. It lacks an inclined end surface area. The hard material cover has two angles 11 and 12 in the transition to the metal profile body, which stabilize the cover. The scraper 1 has the surface 27 with an inclination at an angle 25.

LIST OF REFERENCE NUMBERS

1 creping scraper

2 working edge

3 drying cylinders

4 paper web

5 metal profile body

6 area

7 Hard material cover

8 ramp surface

9 scraper point

10 Hard material coverage depth

11 angular range

12 angle range

13 profile cross-section

14 ramp area

15 difference tilt angle

16 metal profile body depth

17 ramp surface total depth

18 end surface area

19 near the working area

20 base area

21 graduation

22 tilt angle

23 ramp surface transition area

24 depth

25 angles

26 height

27 area

Claims

1. creping doctor (1), which is to be set with a working edge (2) to a drying cylinder (3) to replace a on the drying cylinder (3) rotating paper web (4) and to crepe, with a metal profile body (5), wherein the Working edge (2) by a wear-resistant hard material on the drying cylinder (3) facing the area (6) of the creping doctor (1) is formed, characterized in that the hard material cover (7) in the region of the shoulder surface (8) of the doctor tip ( 9) extends from the working edge (2) over a hard material cover depth (10) of> = about 300 microns into the ramp surface (8) at a total ramp surface (17) of about 800 microns to about 1200 microns.

2. creping doctor (1), which is to be set with a working edge (2) to a drying cylinder (3) to replace a on the drying cylinder (3) circulating paper web (4) and to crepe, with a metal profile body (5) wherein the working edge (2) by a wear-resistant hard material on the drying cylinder (3) facing region (6) of the creping doctor (1) is formed, in particular according to claim 1, characterized in that the run-on surface (8) facing away from the working edge (2) and With respect to a front, near the edge of the edge of the work surface near the edge (14) inclined end surface region (18).

3. creping doctor (1) according to claim 1 or 2, characterized in that the hard material cover (7) is formed substantially to the end of the ramp surface (8).

4. creping doctor (1) according to one of claims 1 to 3, characterized in that the hard material cover (7) on the ramp surface (8) to about 500 microns depth (10) is formed.

5. creping doctor (1) according to one of claims 1 to 4, characterized marked, that the hard material cover (7) of a scraper base region (20) up to the ramp surface (8) in the profile cross-section (13) increases.

6. creping doctor (1) according to one of claims 1 to 5, characterized in that the profile cross section (13) of the hard material cover (7) is triangular.

7. creping doctor (1) according to one of claims 1 to 6, characterized in that the profile cross-section (13) of the hard material cover (7) has a growing pitch.

8. creping doctor (1) according to one of claims 1 to 7, characterized in that the profile cross-section (13) of the hard material cover (7) is continuously growing.

9. creping doctor (1) according to one of claims 1 to 8, characterized marked, that the profile cross section (13) of the hard material cover (7) is constant in sections, with the following each section increases more.

10. creping doctor (1) according to one of claims 1 to 9, characterized in that the profile cross section (13) of the hard material cover (7) has different, pre-introduced angle ranges (11, 12).

11. creping doctor (1) according to one of claims 1 to 10, characterized in that the hard material cover (7) comprises a ceramic material, in particular a metal oxide, silicide, boride, nitride or mixtures thereof, or a metallic hard alloy, or mixtures it.

12. creping doctor (1) according to one of claims 1 to 11, characterized in that the hard material cover (7) alumina, chromium oxide, zirconia, tungsten carbide, chromium carbide, zirconium carbide, tantalum carbide or titanium carbide or mixtures thereof.

13. creping doctor (1) according to one of claims 1 to 12, characterized in that the hard material cover (7) thermally sprayed material, in particular by physical vapor deposition (PVD), chemical vapor deposition (CVD) or Hochgeschwindigkeitsflammspritzeπ (HVOF) applied ,

14. creping doctor (1) according to one of claims 2 to 13, characterized in that the end surface region (18) relative to the front ramp surface area (14) by a differential tilt angle (15) is inclined, the amount is preferably between about 4 ° and about 80 ° is, (more preferably between about 5 ° and about 20 °, more preferably about 10 ° to about 15 °).

15. Creping doctor (1) according to one of claims 2 to 14, characterized in that the inclination of the end surface region (18) with respect to the front ramp surface region (14) is low with a difference inclination angle (15) in particular between about 5 ° to about 15 °.

16. creping doctor (1) according to one of claims 2 to 15, characterized in that the inclination of the end surface area (18) relative to the front ramp surface area (14) is steep with a difference tilt angle (15), in particular between about 30 ° to about 50 °.

17. creping doctor (1) according to one of claims 2 to 16, characterized in that the working edge near the ramp surface area (14) with an inclination angle (22) is inclined, which in particular is negative, with an amount of about 0 ° to 25 °, in particular if the hard material cover is made of ceramic, 0 ° to 40 °, in particular if the hard material cover is a hard metal, in particular 5 ° to 10 °, or in particular positive, in particular with an amount of about 0 ° to about 40 °.

Creping scraper (1) according to one of claims 2 to 17, characterized in that the depth (24) of the front, near the edge of the runner surface area (14) up to a run-up area transition area (23) is up to about 600 to about 800 microns.

19. Creping doctor (1) according to one of claims 2 to 18, characterized in that the end surface region (18) substantially with the end (21) of the hard material cover (7) on the ramp surface (8) begins.

20. Creping doctor (1) according to one of claims 1 to 19, characterized in that the end surface region (13) after about 45% of the total surface tread depth (17) begins, in particular at a depth (24) of the working edge near the ramp surface (14) of about 500th Micrometer, in particular if the total metal profile body depth (16) is about 1200 micrometers, wherein the hard material coverage depth (10) is in particular about 250 micrometers.

21. Creping doctor (1) according to one of claims 1 to 20, characterized in that the end surface region (18) begins in a later run surface transition region (23) when the difference inclination angle (15) becomes greater.

22. creping doctor (1) according to one of claims 1 to 21, characterized in that metal profile body (5) made of hot or cold rolled steel, in particular spring steel, consists.

23. creping doctor (1) according to one of claims 1 to 22, characterized in that a drying cylinder facing surface (27) in the hard material cover (7) at a predetermined angle (25) is introduced.

24. creping doctor (1) according to claim 23, characterized thereby that the angle (25) between about 5 ° and about 15 °, in particular about 6 ° to about 12 °, in particular about 7 °.

25 creping doctor (1) according to any one of claims 23 or 24, characterized in that the surface (27) has a height (26) of about 0.2 mm to about 4 mm, in particular about 2.3 mm to about 3 mm ,

26. A method for producing a creping doctor, in particular according to one of claims 1 to 25, characterized in that the end surface region (18) of the metal profile body (5) for producing an angled surface and / or the surface (27) of the hard material cover (7 ) is to be removed mechanically, in particular to be abraded, wherein the removal of the end surface area occurs in particular before the hard material covering is applied.

27. The use of a creping doctor according to any one of claims 1 to 25, produced in particular by a method according to claim 26, for the production of crepe paper by the creping doctor (1) with a working edge (2) to a drying cylinder (3) with a circulating paper web ( 4) is set and the paper web (4) runs on the run-on surface (8) of the creping doctor (1), creped and then removed from this.