US20070277951A1

US20070277951A1 - Modularly Constructed Paper Machine Covering

Info

Publication number: US20070277951A1
Application number: US10/587,918
Authority: US
Inventors: Arved Westerkamp
Original assignee: Voith Patent GmbH
Current assignee: Voith Patent GmbH
Priority date: 2004-02-06
Filing date: 2004-12-09
Publication date: 2007-12-06
Also published as: EP1711656A1; EP1711656B1; ATE389057T1; DE102004006103A1; WO2005075733A1; DE502004006534D1

Abstract

A covering for paper machines, paperboard machines or tissue machines, which is constructed from a construction kit includes a plurality of prefabricated web-shaped material layers. Each web-shaped material layer is configured dependent upon a category and operating conditions of the covering, and the plurality of prefabricated web-shaped material layers are stacked atop one another and are joined to one another at least in sections, two-dimensionally, and in a manner that prevents the plurality of prefabricated web-shaped material layers from being detached. The invention also relates to a method for producing the inventive covering.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
This invention relates to a method for the modular production of coverings for paper machines, paperboard machines or tissue machines and to a covering for a paper machine, paperboard machine or tissue machine.
2. Description of the Related Art
Paper machines, paperboard machines or tissue machines have coverings in the forming section, press section and drying section.
The different categories of coverings, namely forming meshes, press felts and dryer fabrics, must meet many different requirements, for example with regard to dewatering behavior, moisture adsorption capacity and the like.
Furthermore, coverings of the same category must meet different requirements depending on the operating conditions. For example, the requirements for the structure of the side of a forming mesh facing the fibrous web in the production process for graphic paper differ fundamentally from those for the production of tissue.
Due to the different categories of coverings described above, each of which has to meet many different requirements, the historical development has seen the manufacturers of coverings produce, for practically every category and operating condition, a covering type which differs almost fundamentally from the covering types of other categories and operating conditions.
For example, covering manufacturers often produce forming meshes with different weave patterns for specific customers.

SUMMARY OF THE INVENTION

The current invention provides a method for providing coverings, as well as coverings which are easier and cheaper to produce than those coverings known from the prior art.
The invention is based on the idea of reducing the production costs of coverings for paper machines, paperboard machines or tissue machines by simplifying the production method for the entire product range of paper machine coverings.
The method according to the invention provides for producing different categories of coverings modularly from a construction kit of prefabricated web-shaped material layers. According to the invention, several web-shaped material layers are selected from the construction kit of prefabricated web-shaped material layers depending on the category and operating condition of the covering to be produced. The web-shaped material layers selected from the construction kit are stacked atop one another and joined to one another at least in sections, two-dimensionally, and in a manner that prevents them from being detached.
In other words, a method is proposed which provides a construction kit of prefabricated material layers. By defining a construction kit of prefabricated web-shaped material layers for the entire product range of paper machine coverings and by selecting prefabricated web-shaped material layers from the construction kit, depending on the category and the operating conditions of the covering, the number of different material layers and, for example, weave structures is greatly reduced.
Whereas in the past a different weave structure was required for each operating condition for example, it is possible in accordance with the invention to produce coverings for the different categories and operating conditions by combining several of the prefabricated web-shaped material layers.
According to one embodiment, provision is made for the order in which the selected web-shaped material layers are stacked to depend on the category and the operating conditions of the covering. The flexibility in using the prefabricated material layers is thus increased, as different properties of the covering can be achieved depending on the order in which the selected web-shaped material layers are stacked.
In this connection it should be noted that the prefabricated web-shaped material layers are constructed such that they fulfill, on their own or in combinations, specific functions such as damping properties, dimensional stability, wear stability, surface properties, liquid adsorption capacity and the like.
According to another embodiment, provision is made for the construction kit of prefabricated material layers to include at least one material layer influencing the surface of a fibrous web and at least one wear-stable material layer. In this case the material layer influencing the surface of the fibrous web is understood to be the material layer which terminates the covering in the direction of the fibrous web. Furthermore, the wear-stable material layer is understood to be the material layer which terminates the covering in the direction of the paper machine.
According to another embodiment, provision is made for the construction kit of prefabricated material layers to include at least one dimensionally stable material layer. The dimensionally stable material layer can be configured either as a material layer which is constructed separately from the two previously mentioned material layers or as an integral component of the one or other previously mentioned material layers.
Various possibilities for the construction of the above-mentioned material layers are conceivable.
Another embodiment of the invention provides for the material layer influencing the surface of the material web to be a textile or a non-textile areal structure.
Another embodiment of the invention provides furthermore for the wear-stable material layer to be a textile or a non-textile areal structure.
Another embodiment of the invention provides for the construction kit of prefabricated material layers to include at least one material layer influencing the liquid adsorption capacity. The material layer influencing the liquid adsorption capacity can be constructed either separately from the previously mentioned material layers or as an integral component of one of the previously mentioned material layers.
The material layer influencing the liquid adsorption capacity can be constructed either as a material layer with a high liquid adsorption capacity or as a material layer with a low liquid adsorption capacity.
A material layer with a high liquid adsorption capacity should have a liquid adsorption capacity which is greater than 50% of the total capacity of the material layer, in particular preferably greater than 70% of the total capacity of the material layer and most preferably greater than 80% of the total capacity of the material layer.
A material layer with a low liquid adsorption capacity should have a liquid adsorption capacity which is less than 50% of the total capacity of the material layer, in particular preferably less than 30% of the total capacity of the material layer and most preferably less than 20% of the total capacity of the material layer.
According to another embodiment of the invention, provision is made for the construction kit of prefabricated web-shaped material layers to include at least one anti-rewetting material layer.
Furthermore, other embodiments provide for the dimensionally stable material layer and/or the material layer influencing the liquid adsorption capacity and/or the anti-rewetting material layer to be textile or non-textile areal structures.
A textile areal structure is understood to be a weave structure or a fleece or a thread plaiting or a warp knitting.
Furthermore, a non-textile areal structure is understood to be a structured and/or penetrated film or a structured and/or penetrated membrane and/or a foamed layer.
It is advantageous, for example, for the material layer with a large liquid adsorption capacity to be a foamed layer.
Furthermore, it is advantageous for the material layer with a small liquid adsorption capacity to be a foamed layer or a penetrated film or a membrane.
Furthermore, it is advantageous for the foamed layer to have a defined pore size. By providing a defined pore size it is possible, for example, to establish the liquid adsorption capacity and hence the dewatering behavior. Furthermore, it is also conceivable for the foamed layer belt to have several defined pore sizes.
According to an embodiment of the invention the foamed layer has a defined pore transverse profile (i.e., different pore sizes in the transverse profile of the material layer). It is thus possible to selectively establish the dewatering behavior and the pressing behavior by way of the web width of the paper machine covering, as the result of which the fibrous web transverse profile can be selectively established.
A film mentioned above can be produced by an extrusion method and/or a rolling method for example.
Various possibilities for joining together the several material layers selected from the construction kit are conceivable.
For example, it is possible for at least two of the material layers to be joined together chemically. Furthermore, it is possible for at least two of the material layers to be joined together mechanically and/or by means of a textile joining method. The different material layers of a covering according to the invention can be joined together by just one or the other ways. However, it is also possible for the material layers to be joined together not only mechanically but also by textile and chemical ways.
For example, a first material layer of a covering according to the invention can be joined mechanically to a second material layer and the second material layer can be joined chemically to a third material layer. Furthermore, the third material layer can be joined by a textile joining method to a fourth material layer of this covering, with the fourth material layer being joined mechanically and chemically to a fifth material layer.
According to another embodiment the chemical bond is effected by an interface-active bond. In this connection an interface-active bond is understood to be a bond resulting from vulcanizing or melting or welding (i.e., ultrasonic welding). In other words, the interfaces of the two material layers which are to be joined together are changed/activated in such a way that they bond together without a bonding medium.
Another embodiment of the invention provides for the chemical bond to be effected by introducing a bonding medium. In this case the bonding medium can be an adhesive for example.
Furthermore it is possible for the bonding medium itself to form a material layer between the joined material layers, in which case the bonding medium is a foamed material layer for example, which is arranged between the material layers that are joined together and bonds said material layers together.
The bonding medium constructed as a separate material layer can fulfill specific functions on its own or in combination with one or more material layers. For example, by combining the bonding medium with one or more material layers it is possible to exert an advantageous influence on the properties of the covering according to the invention.
If the material layers are joined together mechanically it is conceivable for them to be pressed together.
If the material layers are joined together by a textile joining method it is possible for them to be sewn or pinned together.
If the covering is one which is not constructed of material webs in the form of endless belts, it makes sense for the various web-shaped material layers which are stacked atop one another to be joined together, two-dimensionally, in sections that are mutually offset in machine direction so that the covering forms two end areas which complement each other in form and function and can be joined together. Through the material layers which are mutually offset in machine direction and joined together, two-dimensionally, in sections, the covering forms two end areas which complement each other in form and function and can be joined together, two-dimensionally, so that the covering is constructed in the form of an endless belt. The two-dimensional bond between the two end areas is particularly stable and durable.
If the covering is constructed of several material layers arranged side by side over its width, it also makes sense for the material layers which are stacked atop one another to be mutually offset at least in sections transverse to the machine direction so that above and/or under neighboring material layers of a certain layer of the covering there is always a material layer which overlaps with both material layers arranged side by side.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of (an) embodiment(s) of the invention taken in conjunction with the accompanying drawing(s), wherein:
FIG. 1 is a detail in longitudinal section of a forming mesh according to the invention,
FIG. 2 is a detail in longitudinal section of a press felt according to the invention,
FIG. 3 is a detail in longitudinal section of a dryer fabric according to the invention,
FIG. 4 is shows the two end areas of the forming mesh of the invention according to FIG. 1,
FIG. 5 is a detail in cross section of a forming mesh according to the invention,
FIG. 6 is a detail in cross section of a press felt according to the invention,
FIG. 7 is a detail in cross section of a dryer fabric according to the invention.
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification(s) set out herein illustrate(s) one preferred embodiment of the invention, in one form, and such exemplification(s) (is)(are) not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 to 4 show coverings which are produced from a construction kit of prefabricated web-shaped material layers 2, 3, 4, 11 and 15. All the web-shaped material layers 2, 3, 4, 11 and 15 of the construction kit are formed in this embodiment as non-textile areal structures.
FIG. 1 shows in longitudinal section in machine direction sections of a forming mesh 1 according to the invention. The forming mesh 1 has a paper-side web-shaped material layer 2 through which the surface of the fibrous web formed on the forming mesh is essentially influenced, and a machine-side web-shaped material layer 3 through which the wear behavior of the forming mesh 1 is essentially influenced. The machine-side material layer 3 is thus a wear-stable material layer 3. In the embodiment in question the machine-side material layer 3 also has dimension-stabilizing properties. The machine-side material layer 3 is thus also a dimension-stable material layer 3, as the result of which the dimension-stable and the wear-stable material layer 3 form an integral unit.
Arranged between the paper-side material layer 2 and the machine-side material layer 3 is a material layer 4 influencing the liquid absorption capacity.
The material layers 2 to 4 were taken from the construction kit of prefabricated web-shaped materials layers 2, 3, 4, 11 and 15 in order to produce the forming mesh 1 of the invention (see also FIGS. 2 and 3).
In the embodiment in question the material layer 2 is formed as a non-textile areal structure in the form of a penetrated film with holes 5 and is produced from a material such as PE, PET, PPS or PA. The paper-side material layer 2 is undetachably joined, two-dimensionally at the interface 7, to the material layer 4 influencing the liquid absorption capacity by chemical ways through application of a bonding medium 72 in the form of an adhesive 72.
The material layer 4 influencing the liquid absorption capacity is formed as a foamed layer with pores 9. In this case the pores have a defined size.
In the embodiment in question the material layer 3 is formed as a non-textile areal structure in the form of a penetrated film with holes 6 and is produced from a material such as PE, PET, PPS or PA. The machine-side material layer 3 is undetachably joined, two-dimensionally at the interface 8, to the material layer 4 influencing the liquid absorption capacity by chemical ways through application of a bonding medium 72 in the form of an adhesive 72.
FIG. 2 shows in longitudinal section in the machine direction sections of a press felt 10 according to the invention. The press felt 10 is formed by the paper-side web-shaped material layer 2 known from FIG. 1, the machine-side web-shaped material layer 3 known from FIG. 1, the material layer 4 influencing the liquid absorption capacity known from FIG. 1, by a material layer 11 likewise influencing the liquid absorption capacity and by an anti-rewetting material layer 15.
All the material layers 2, 3, 4, 11 and 15 were taken from the construction kit of prefabricated web-shaped material layers 2, 3, 4, 11 and 15 in order to produce the press felt 10 of the invention. The order in which the individual material layers are stacked atop one another is defined by the operating conditions for which the press felt 10 of the invention is designed.
The material layer 2 is joined, at the interface 13, to the anti-rewetting material layer 15 by chemical ways through application of a bonding medium 72 in the form of an adhesive 72.
The material layer 11 influencing the liquid absorption capacity is formed as a foamed layer with pores 12. In this case the pores 12 have a defined size which is greater than the size of the pores 9. The anti-rewetting material layer 15 is joined, at the interface 16, to the material layer 11 influencing the liquid absorption capacity by chemical ways through application of a bonding medium 72 in the form of an adhesive 72.
The two material layers 4 and 11 influencing the liquid absorption capacity are undetachably joined together, two-dimensionally at the interface 14, by chemical ways in the form of an adhesive bond 72.
The machine-side material layer 3 is undetachably joined, two-dimensionally at the interface 8, to the material layer 4 influencing the liquid absorption capacity by chemical ways through application of a bonding medium 72 in the form of an adhesive 72.
FIG. 3 shows in longitudinal section in the machine direction sections of a dryer fabric 20 according to the invention. The dryer fabric 20 is formed from the paper-side web-shaped material 2 known from FIGS. 1 and 2 and from the machine-side web-shaped material layer 3 known from FIGS. 1 and 2.
The two material layers 2 and 3 are undetachably joined together, two-dimensionally at the interface 21, by chemical ways in the form of an adhesive bond 72.
FIG. 4 shows a detail in longitudinal section in the machine direction of the forming mesh 1 of the invention in the area of the two end areas 30 and 31 of the forming mesh 1. In the situation illustrated, the two end areas 30 and 31 are not yet brought fully into contact with each other
As is evident from FIG. 4, the web-shaped material layers 2, 3 and 4 are mutually offset in machine direction and joined together, two-dimensionally, in sections. As the result, the two end areas complement each other in form and function and can be joined together two-dimensionally.
FIGS. 5 to 7 show coverings which are produced from a construction kit of prefabricated web-shaped material layers 41, 42 and 61.
FIG. 5 shows in cross section, meaning transverse to the machine direction, sections of a forming mesh 40 according to the invention. The forming mesh 40 has a paper-side web-shaped material layer 41 through which the surface of the fibrous web formed on the forming mesh is essentially influenced, and a machine-side web-shaped material layer 42 through which the wear behavior of the forming mesh 40 is essentially influenced. The machine-side material layer 42 is thus a wear-stable material layer 42. In the embodiment in question the paper-side 41 and machine-side material layer 42 also have dimension-stabilizing properties.
The material layers 41 and 42 are formed in this embodiment as textile areal structures in the form of weave structures 41 and 42.
The weave structure 41 is formed by the warp threads 45 and the weft threads 44, whereby each weft thread 44 passes alternately under and over a warp thread 45 in order to form a smooth weave pattern, thus creating a smooth contact area for the paper fibers.
The weave structure 42 is formed by the warp threads 46 and the weft threads 47, whereby each weft thread 47 in a repeat unit passes under two consecutive warp threads 46 and then over one warp thread 46 in order to form a particularly wear-stable weave pattern in which the highly tensioned warp threads are protected by the weft threads 47 against wear.
In the embodiment in question the two weave structures 41 and 42 are joined together, two-dimensionally at the interfaces 48 and 19, by chemical ways through a bonding medium. Here the bonding medium itself forms a foamed material layer 43, which is arranged between the two joined weave structures 41 and 42. The foamed material layer 43 has pores 50 with a defined size. This means that the foamed material layer 43 has the function of joining together the two weave structures 41 and 42 in addition to the function of influencing the liquid absorption capacity.
FIG. 6 shows in cross section, meaning transverse to the machine direction, sections of a press felt 60 according to the invention. The press felt 60 has the machine-side weave structure 42 known from FIG. 5 and a fleece 61 with fibers 62.
The fleece 61 and the weave structure 42 are joined together at the two interfaces 63 and 49 by the bonding medium 43 forming a material layer 43. In the case of the press felt 60, the bonding medium again has the function of joining together the weave structure 42 and the fleece 61 as well as the function of influencing the liquid absorption capacity of the press felt 60.
FIG. 7 shows in cross section, meaning transverse to the machine direction, sections of a dryer fabric 70 according to the invention. The dryer fabric 70 has the paper-side weave structure 41 known from FIG. 5 and the machine-side weave structure 42 known from FIG. 5.
The two weave structures 41 and 42 are joined together, two-dimensionally, by chemical ways through a bonding medium 71 in the form of an adhesive 71.
While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
List of Reference Numerals:

1 Forming mesh
2 Paper-side material layer
3 Machine-side material layer
4 Material layer defining the liquid adsorption capacity
5 Holes (paper-side material layer)
6 Holes (machine-side material layer)
7 Interface
8 Interface
9 Pores (material layer defining the liquid adsorption capacity)
10 Press felt
11 Material layer defining the liquid adsorption capacity
12 Pores (material layer defining the liquid adsorption capacity)
13 Interface
14 Interface
15 Anti-rewetting material layer
16 Interface
20 Dryer fabric
21 Interface
30 End area
31 End area
40 Forming mesh
41 Weave structure (paper-side material layer)
42 Weave structure (machine-side material layer)
43 Bonding medium (material layer defining the liquid adsorption capacity)
44 Weft thread (weave structure)
45 Warp thread (weave structure)
46 Warp thread (weave structure)
47 Weft thread (weave structure)
48 Interface
49 Interface
50 Pores (bonding medium)
60 Press felt
61 Fleece
62 Fibers (fleece)
63 Interface
70 Dryer fabric
71 Bonding medium
72 Adhesive

Claims

1-36. (canceled)

37. A method for the modular production of coverings of different categories for use in one of paper machines, paperboard machines and tissue machines, said method comprising the steps of:

prefabricating a construction kit of web-shaped material layers;

selecting a plurality of said web-shaped material layers from said construction kit depending on a category and operating condition of the covering to be produced;

stacking said web-shaped material layers atop one another; and

joining said web-shaped material layers to one another at least in sections, two-dimensionally, and in a manner that prevents said web-shaped material layers from being detached.

38. The method according to claim 37, wherein said stacking of said web-shaped material layers comprises stacking them in an order which depends on the category and the operating conditions of the covering.

39. The method according to claim 37, wherein said joining of said web-shaped material layers comprises joining at least two web-shaped material layers together chemically.

40. The method according to claim 39, wherein said joining at least two web-shaped material layers together chemically is effected by an interface-active bond.

41. The method according to claim 40, wherein said interface-active bond is effected by one of vulcanizing, welding and melting.

42. The method according to claim 39, wherein said joining at least two web-shaped material layers together chemically is effected by adding a bonding medium.

43. The method according to claim 42, wherein said bonding medium is an adhesive.

44. The method according to claim 42, wherein said bonding medium forms a material layer which is arranged between said joined material layers.

45. The method according to claim 44, wherein said bonding medium forms a foamed material layer between said joined material layers.

46. The method according to claim 37, wherein said joining of said web-shaped material layers comprises joining at least two web-shaped material layers together mechanically.

47. The method according to claim 46, wherein said joining at least two web-shaped material layers together mechanically is effected by pressing.

48. The method according to claim 37, wherein said joining of said web-shaped material layers comprises joining at least two web-shaped material layers together by a textile joining method.

49. The method according to claim 48, wherein said textile joining method is effected by one of sewing and pinning.

50. A covering for use in one of paper machines, paperboard machines and tissue machines, said covering comprising:

a construction kit including a plurality of prefabricated web-shaped material layers, each said web-shaped material layer being configured dependent upon a category and operating conditions of the covering, said plurality of prefabricated web-shaped material layers being stacked atop one another and joined to one another at least in sections, two-dimensionally, and in a manner that prevents said plurality of prefabricated web-shaped material layers from being detached.

51. The covering according to claim 50, wherein said web-shaped material layers have a stacking order that is dependent upon the category and the operating conditions of the covering.

52. The covering according to claim 50, wherein said web-shaped material layers fulfill specific functions.

53. The covering according to claim 50, wherein said web-shaped material layers are joined to one another in sections via a bonding medium that fulfills specific functions one of on its own and in combination with at least one of said material layers.

54. The covering according to claim 50, wherein the construction kit of prefabricated web-shaped material layers comprises at least one material layer influencing the surface of a fibrous web and at least one wear-stable material layer.

55. The covering according to claim 54, wherein said material layer influencing the surface of a fibrous web is one of a textile areal structure and a non-textile areal structure.

56. The covering according to claim 54, wherein said wear-stable material layer is one of a textile areal structure and a non-textile areal structure.

57. The covering according to claim 50, wherein the construction kit of prefabricated web-shaped material layers comprises at least one dimension-stable material layer.

58. The covering according to claim 57, wherein said dimension-stable material layer is one of a textile areal structure and a non-textile areal structure.

59. The covering according to claim 50, wherein said construction kit of prefabricated web-shaped material layers comprises at least one material layer influencing the liquid adsorption capacity.

60. The covering according to claim 59, wherein said material layer influencing the liquid adsorption capacity has one of a high liquid adsorption capacity and a low liquid adsorption capacity.

61. The covering according to claim 60, wherein said material layer with a high liquid adsorption capacity is one of a textile areal structure and a non-textile areal structure.

62. The covering according to claim 50, wherein said construction kit of prefabricated web-shaped material layers comprises at least one anti-rewetting material layer.

63. The covering according to claim 62, wherein said anti-rewetting material layer is one of a textile areal structure and a non-textile areal structure.

64. The covering according to claim 50, wherein said textile areal structure is one of a weave structure, a fleece, a thread plaiting, and a warp knitting.

65. The covering according to claim 50, wherein said non-textile areal structure is one of:

at least one of a structured film and a penetrated film;

at least one of a structured membrane and a penetrated membrane; and

a foamed layer.

66. The covering according to claim 65, wherein said film is at least one of extruded and rolled.

67. The covering according to claim 65, wherein said foamed layer has a defined pore size.

68. The covering according to claim 65, wherein said foamed layer has a plurality of defined pore sizes.

69. The covering according to claim 68, wherein said foamed layer has a defined pore size in a transverse profile.

70. The covering according to claim 50, wherein said web-shaped material layers are joined to one another with at least one of a chemical and a mechanical bond.

71. The covering according to claim 70, wherein said web-shaped material layers are joined to one another by different bonding methods depending on the category, the operating conditions, and the material layers to be joined together.

72. The covering according to claim 71, wherein said web-shaped material layers are mutually offset in one of a machine direction and a transverse machine direction and joined together, two-dimensionally, in sections so that the covering forms two end areas which complement each other in form and function and can be joined together.