WO2008034952A1

WO2008034952A1 - A blade and a method for manufacturing the blade

Info

Publication number: WO2008034952A1
Application number: PCT/FI2007/050501
Authority: WO
Inventors: Ilkka Eskelinen
Original assignee: Ike-Service Oy
Priority date: 2006-09-20
Filing date: 2007-09-19
Publication date: 2008-03-27
Also published as: FI20065573A0

Abstract

The invention relates to a blade (10), on the edge of a base structure (15) of which there is at least one wear area (17.1, 17.2). The wear area is arranged to be formed of at least two wear tips (17.1, 17.2) arranged on the same edge of the base structure (15). The invention also relates to a method for manufacturing the blade.

Description

A BLADE AND A METHOD FOR MANUFACTURING THE BLADE

This invention relates to a blade according to the preamble of claim 1 on the edge of the base structure of which is arranged at least one wear area. The invention also relates to a method according to the preamble of claim 5 for manufacturing the blade, e.g. a composite doctor blade of a paper machine, as die pultrusion.

Nowadays, composite blades are used e.g. in the doctors of paper machines. Known are blades having a base structure and one wear edge arranged in the base structure. As a result of wear, many times the blade has to be replaced by a new one, which causes, inter alia, enormous material losses in the form of composite blade waste.

Known as such is also double-doctor operation by means of which one tries to e.g. ensure the arrangement of doctor operation in critical positions. In these, there are successively two blades against the surface being doctored. Both blades constitute their own operational parts separate from each other, which both also have their own holders.

The object of this invention is to provide a novel and more versatile than earlier blade. The blade according to the invention is characterised by that the wear area is arranged to be formed of at least two wear tips arranged on the same edge of the base structure.

The advantageous embodiments of the blade according to the invention are characterised by what is stated in dependent claims 2- 4.

The method according to the invention is characterised by that, in the method, a blade blank mat is manufactured from which blade blanks are cut.

The advantageous embodiments of the method according to the invention are characterised by what is stated in dependent claims 6- In the blade according to the invention, there are on the same edge interestingly several wear areas. Such a blade enables arranging the double-doctor operation. Along with it, it is possible to manage with only one blade holder. Other advantages of the invention are depicted later in a specific part of the description.

The invention, which is by no means limited by embodiments to be presented in the following, will be described in more detail by referring to the accompanying drawings in which:

Fig. 1 shows a crude principal view of an example of the manufacturing line of a blade according to the invention,

Fig. 2 axonometrically shows the base structure of the blade manufactured according to the invention,

Figs. 3a and 3b show an end view of the blade seen before and after a diagonal cut,

Figs. 4a and 4b show another embodiment in which two separate blades are obtained from the diagonally cut base structure according to Fig. 3b,

Figs. 5a and 5b show an embodiment in which the used wear edges of the blade are cut to introduce unused wear edges for use, and

Fig. 6 shows the blade according to the invention in double-doctor operation.

Fig. 1 shows an example of the method according to the invention for manufacturing a composite blade 10. The blade 10 according to the invention is manufactured at least partly using pultrusion technology in a process 20 which is also known as die pultrusion. For those skilled in the art, the die pultrusion 20 as such is conventional technology, thus there is no need in this connection to describe it in great detail.

However in the pultrusion process 20, fibres/a fibre mat 11 are/is pulled through basic stages characteristic of the pultrusion technology, resulting in a blade blank 22, from which blades 10 can be detached, to be reeled onto a reel 27. The fibres 11 can be e.g. carbon fibre and/or glass fibre and/or aramid fibre and/or boron fibre, this being in no way limited by the basic idea of the invention. An example of the ratio forming a composite of carbon fibre and glass fibre is 40/60. The direction of fibres in the composite can be arbitrary. According to an embodiment, the glass-fibre layers can be oriented e.g. parallel to the longitudinal axis of the blade 10, while at least some of the layers containing carbon fibre can deviate from the direction of the longitudinal axis of the blade 10.

The blade blank 22 consists of a rigid base structure 15 having several fibre layers as a laminate structure. In Fig. 1, the pull direction of the blank 22 is shown by an arrow. Of the stages of the process 20, reference can be made in this connection to at least an impregnation stage 12 and a curing stage 14.

The fibres 11 can be arranged in a preset battery of several reels 21. From there, guides (not shown) are used to lead them first to the impregnation stage 12. There, the fibres 11 are impregnated with an excess of some selected matrix material 23, such as e.g. polymer material. As examples of these can be mentioned possibly fluoridised thermoset plastic, duraplastic or (epoxy) resin. Impregnation is carried out to an excess, the excess then running out already in connection with the impregnation stage 12 or evaporating in the actual curing stage 14. The impregnation 12 is followed by the actual die pultrusion i.e. the curing stage 14.

In the die pultrusion 14, the fibres 11 impregnated with the polymer 23 are pulled through a die 14' of a set kind. A set temperature and pressure effect is also associated with the die pultrusion 14. As a result of these, the polymer 23 dries and gains strength to its final hardness and the fibres 11 stiffen into the desired shape defined by the die 14'. The curing stage 14 can be formed of zones with different temperatures/pressure effects, the arranging of which is obvious to those skilled in the art.

The completed blade blank 22 which is e.g. reeled on the reel 27 is pulled using pulling means 19. The pulling means 19 can consist of e.g. a nip formed by at least two rolls through which the blade blank 22 travels onto the reel 27. In the case of the narrowest blade type, e.g. 100-150 metres of the blade blank 22 can be reeled onto the reel 27, after which it can be changed. The finished blades 10 can be detached from the blanks 22 e.g. by cutting them into customer size in a later stage or also alternatively instead of reeling.

Fig. 2 shows the base structure 15 of the blade according to the invention as an axonometric illustration. According to a first embodiment in the manufacturing method according to the invention, when forming the blade blank 22, in the continuous composite base structure 15 of the blade is formed in the pultrusion process 20 on at least one edge or even on both edges a groove 16.1, 16.2 in the longitudinal direction of the blade. In the die 14', there are shapings for this by means of which in the base structure 15 is formed on its both narrow edges such a recess groove 16.1, 16.2.

Another way of manufacturing the base structure 15 provided with the groove 16.1, 16.2 is to manufacture a composite base structure 15 without grooves 16.1, 16.2 in the pultrusion process 20. Then, the grooves 16.1, 16.2 can be e.g. machined afterwards on one or even both elongated narrower edges of the base structure 15. Fig. 2 shows an example of the base structure 15 provided with grooves 16.1, 16.2 being produced in the process according to Fig. 1. On both sides of the grooves 16.1, 16.2, there are finger-like tips 17. An example of the depth of the groove 16.1, 16.2 can be 5-75 mm (or even 100 mm). Correspondingly, the total width of the base structure 15 of the blade 10 can be e.g. 50-200 mm. The width of the groove 16.1, 16.2 i.e. the distance between the tips 17.1, 17.2 can be e.g. 1-300 mm.

In Fig. 3a, onto both edges of the base structure 15 provided with the grooves 16.1, 16.2 is directed a diagonal cut Ci, whereby in the base structure 15 are interestingly formed according to Fig. 3b four tips 17.1-17.4, two on both of its longitudinal edges. Instead of the diagonal cut, the tips can also be provided in the pultrusion process 20 with a die enabling the forming of tips. The tips 17.1, 17.2 and 17.3, 17.4 on the same edge are suitably on different levels in relation to each other, whereby in one base structure 15 there are four wear edges. By changing the cut angle, the levels and the shape of the tips 17.1-17.4 can be affected. In Fig. 3b, the tips 17.1-17.4 are cut along a parallel cutting line Ci, but the cutting line Ci can also be divergent.

Figs. 4a and 4b show another embodiment of the blade according to the invention. There, the base structure 15 of the blade is cut along the line C₂ either diagonally or straight through in the middle. As a result are produced according to Fig. 4b two blades 10.1, 10.2, in which both blades 10.1, 10.2, there are at least on one edge two wear edges 17.3, 17.4 and 17.1, 17.2. If the diagonal cut is directed also to the opposite edge, also one wear edge 24.1, 24.2 is formed for it. Such blades 10.1, 10.2 can be used e.g. in different doctoring positions.

Figs. 5a and 5b show a first embodiment in which the originally longer wear edges 17.1, 17.3 of the blade 10 in Fig. 5a have been worn out. In this embodiment, only the longer ones of the tips of the blade 10 have been in contact with a surface being doctored, such as e.g. with a roll or a cylinder. The original appearance of the wear edges 17.1, 17.2 is shown with dashed lines and the worn tip with designation W. Now both worn-out wear edge stubs are cut according to Fig. 5a along the line C3. As a result of cutting, it is possible to utilise the unused originally shorter wear areas 17.2, 17.4 of the blade 10, when the originally longer wear areas 17.1, 17.3 are now out of the way of these shorter wear areas 17.1, 17.4. The diagonal cuts Ci performed to the base structure 15 provided with the grooves 16.1, 16.2 enable an interestingly versatile utilisation of the blade 10, 10.1, 10.2. Now the same blade can be used even four times. Then, the blade can be turned in a desired direction when the wear margin of one wear edge has been worn out. On the other hand, the blade blank can also be split in two in the direction of its longitudinal axis when manufacturing blades. Then, three blades are obtained of one blank stub. The work edge of the blade provided with the groove is then provided with two wear areas and the opposite edge possibly with one wear area.

Fig. 6 shows another embodiment of a possibility to arrange doctor operation provided by the blade 10.1 according to the invention. According to this embodiment, the blade 10.1 according to the invention can be interestingly utilised also in arranging double-doctor operation. Then, both wear tips 17.1, 17.2 on the longitudinal edge of the blade 10.1 are simultaneously in doctor contact with the surface being doctored, now with a roll 26. The blade 10 is set in the blade holder 27, of which only one is now required. It should be understood that the blade holder is described here as extremely simplified and tailoring different blade holders for the blade 10.11 according to the invention is obvious to those skilled in the art. Into the groove between the tips 17.1, 17.2 can be directed different sprays or blows or suctions for removing impurities. The blows can be e.g. at the ends of the blade 10.1 or even inside it in the groove. With the suitable diagonal cut and the suitable positioning of the blade holder 27 in relation to the roll 26 is obtained desired contact between the wear tips 17.1, 17.2 and the roll 26.

In some cases, the base structure 15 can be, instead of the laminar structure shown in Figs. 2-6, also a shaped profile in which e.g. the joining point of the tips 17.1, 17.2 to the base structure 15 can be locally reinforced. Then, the base structure 15 still fits as thin in its doctor holder 27 and, on the other hand, also the distance between the tips 17.1, 17.2 (groove 16.1) is obtained large enough e.g. for enabling viable dirt removal.

It is possible to manufacture blades 10 for several different operating positions from the blade blank 22 manufactured in the manner according to the invention. Besides being able to use the blade 10 as a doctoring and cleaning blade in a paper or board machine, it can also be applied in coating machines/devices, pulp machines, printing machines, tissue machines or generally in applications related to web formation, paper-making and closely related fields and finishing/processing sites in which doctoring is performed for one or more purposes. The blade 10 can be further used in the above- mentioned machines as a cleaning blade maintaining runnability and paper quality and/or as a servicing blade in which the surface being doctored is serviced (e.g. ground/polished) by the blade in order to maintain the original state of the roll or to achieve it. In the case of a cleaning blade, undesirable materials which have adhered on the surface of the roll are removed from it. Furthermore, the fibre- reinforced reinforced plastic composite blade 10 according to the invention is applicable for use as a paper-web transfer doctor.

It should be understood that the above description and the figures related to it are solely intended to illustrate the present invention. The invention is thus not limited solely to the embodiments described above or defined in the claims, but many different variations and modifications of the invention which are possible within the scope of the inventive idea defined by the accompanying claims are obvious to those skilled in the art.

Claims

1. A blade (10) on the edge of a base structure (15) of which is arranged at least one wear area (17.1, 17.2), characterised in that the wear area is arranged to be formed of at least two wear tips (17.1, 17.2) arranged on the same edge of the base structure (15).

2. A blade according to claim 1, characterised in that the wear tips (17.1, 17.2) are coated with wear-resistant material, such as silicon carbide or aluminium oxide.

3. A blade according to claim 1 or 2, characterised in that the material of the blade (10) is reinforced thermoset or duraplastic, the thermal resistance of which is about 350-

45O⁰C, advantageously about 400⁰C.

4. A blade according to any one of claims 1-3, characterised in that in a groove between the wear tips (17.1, 17.2) is conveyed liquid for providing a lubrication, cleaning, cooling etc. effect.

5. A method for manufacturing the blade, e.g. a composite doctor blade of a paper machine, as die pultrusion, characterised in that, in the method, a blade blank mat (22) is manufactured from which blade blanks are cut.

6. A method according to claim 5, characterised in that the blade blank mat (22) is reeled onto a reel (27).

7. A method according to claim 5 or 6, characterised in that, when forming the blade blank mat (22), a groove (16.1, 16.2) parallel to the longitudinal direction of the blade is formed in a pultrusion process (20) at least on one edge of a continuous composite base structure (15) of the blade (10).

8. A method according to claim 5, characterised in that, when forming the blade blank mat (22), the groove (16.1, 16.2) in the longitudinal direction of the blade is formed in the pultrusion process (20) on both edges of the continuous composite base structure (15) of the blade (10).

9. A method according to claim 5 or 6, characterised in that on both elongated narrower edges of the blade cut from the blade blank mat (22) are machined grooves (16.1, 16.2).

10. A method according to any one of claims 5-9, characterised in that the depth of the grooves (16.1, 16.2) is 5-100 mm, their width 1-300 mm, and that the total width of the base structure (15) is 50-200 mm.

11. A method according to any one of claims 5-10, characterised in that onto both edges of the base structure (15) provided with the grooves (16.1, 16.2) is made a diagonal cut (Ci), whereby in the base structure are formed four tips (17.1-17.4), two on both of its longitudinal edges.

12. A method according to any one of claims 5-11, characterised in that the base structure (15) of the blade is cut along a cutting line (C₂) either diagonally or straight through in the middle, whereby two blades (10.1,

10.2) are formed.