Patent Application
20240052569
The present invention relates to a method for manufacturing a support body arrangement for an apparatus having an extended nip formed between the support body and a counter-pressure member. The invention also relates to a support body arrangement and a support body for a support body arrangement. The apparatus having an extended nip is suitably a paper machine.
In a paper making machine, an extended nip press is generally used for pressing water out of a newly formed wet fibrous web but an extended nip may also be used for other purposes in a paper making machine, e.g. calendering. Although extended nip presses were first introduced for heavy grades such as paperboard, they have also come to be used for lighter grades such as printing paper and even for tissue paper. When making tissue paper, the extended nip press is often formed by an extended nip roll and a Yankee drying cylinder that acts as a counter roll for the extended nip roll.
An extended nip press, especially in a machine for making tissue paper, is typically formed by an extended nip roll that comprises a support body with a working surface that is pressed against the counter roll by pressurized chambers inside or below the show acting to push the support body in a first direction towards the counter roll.
Within the art, rigid shoes typically made from metallic materials are known but it is especially advantageous to use softer, more flexible support bodies that are elastically deformable in order to adjust the extended nip as desired and achieve a suitable pressure profile.
Although support bodies of the flexible type are known, for instance through U.S. Pat. No. 9,181,655 and EP 2013412, manufacturing them is generally complicated and involves a multi-step process using a plurality of materials having different properties and requiring careful monitoring in order to form the support body as desired. Also, replacing the support body after prolonged use requires interruption of operation of the paper machine and costly replacements. The time needed to repair and/or replace the support body is especially costly, since it requires the paper machine to be idle.
There is therefore a need for improvements within this area.
The object of the present invention is to eliminate or at least to minimize the problems discussed above. This is achieved by a support body arrangement, a method for manufacturing a support body arrangement, a support body and a method for replacing a support body of a support body arrangement according to the appended independent claims.
The method according to the present invention relates to manufacturing a support body arrangement for an apparatus having an extended nip formed between the support body and a counter-pressure member, and the method comprises
By providing the base body separately from the support body, each of these bodies may be manufactured in separate processes and be mounted together using the mounting structure so that the support body arrangement is formed. This provides a significant advantage over known prior art solutions, since manufacture of the base body and of the support body in separate processes is easier and more efficient than joining them together in the known complex manufacturing processes. By providing the mounting structure, the support body arrangement may be manufactured through a combination of existing components as desired, even on site near a paper machine that needs replacing of the support body arrangement for the extended nip press. The manufacturing method according to the invention is more robust than the prior art methods and allows for combinations of different designs of the base body and the support body with only minor modifications to the overall manufacturing method.
Suitably, the mounting structure comprises an adhesive and the mounting of the support body on the base body comprises applying the adhesive to at least one of the base body and the support body and bringing the base body and the support body into contact with each other with the adhesive between them. Thereby, the support body is fixed to the base body by means of the adhesive and movement of the support body in relation to the base body is prevented. This is an easy and convenient way of mounting the support body arrangement. It is also especially to be noted that the mounting structure may comprise other fastening means that are combined with the adhesive in order to achieve an especially secure fastening.
The mounting structure may also comprise a first portion that is fixedly attached to the support body and a second portion that is fixedly attached to the base body. The mounting of the support body on the base body then comprises bringing the first portion and the second portion into engagement with each other. Thereby, the support body may be mounted on the base body in an easy and reliable way. By the first portion and the second portion already being fastened to the support body and the base body, respectively, the mounting structure is able to achieve a time efficient and stable mounting of the support body arrangement. In some embodiments, the first portion and/or the second portion may be fixedly attached by being molded into the support body and/or the base body, but in other embodiments at least one of the first and the second portion may be fastened by other means such as being screwed or clamped to the support body or the base body.
Alternatively, the mounting structure comprises at least two side portions that are configured to extend from the base body in the first direction at a distance from each other. The mounting of the support body on the base body then comprises inserting the support body between the at least two side portions to rest on the base body. Thereby, the support body may be held in place by friction against the at least two side portions in order to provide a time efficient and reliable mounting of the support body arrangement. In some embodiments, the at least two side portions are present only on ends of the base body in a direction transversal to a direction in which a web or paper travels during use of the support body arrangement. In other embodiments, the at least two side portions can instead be arranged to partly or entirely enclose the support body so that only the working surface is left uncovered. The number of side portions and their distribution may thus be varied depending on factors such as properties of the paper machine where the extended nip press it mounted and/or depending on properties of the support body and/or base body as desired.
Suitably, the mounting structure may comprise a separate mounting body with a base body engagement part and a support body engagement part, so that the mounting of the support body on the base body comprises bringing the base body into engagement with the base body engagement part and the support body into engagement with the support body engagement part in order to fixate them in relation to each other. Thereby, the mounting structure may be provided as a separate component and be combined with the base body and the support body during mounting. This is especially beneficial since the base body and the support body may be manufactured separately without being adapted to fit each other as long as the mounting structure is able to interact with them both. Also, in some applications it is advantageous to avoid the presence of parts of the mounting structure in the base body and/or the support body since the support body especially may then be designed and manufactured to have properties that are optimal for a particular paper machine or field of use without having to consider how the mounting structure could affect such properties.
Suitably, the mounting structure may be disengaged in order to remove the support body from the base body. This is especially beneficial in allowing for the support body to be releasably arranged so that a damaged and/or worn support body may be replaced. Also, for situations where the paper machine is switched from one set of operation parameters to another it becomes possible to remove and replace the support body in the support body arrangement on site so that the same base body may be used with the new operation parameters. Conversely, it is possible to replace a damaged or worn base body while retaining the support body due to the mounting structure being able to disengage.
The present invention also comprises a support body arrangement for an apparatus having an extended nip formed between the support body arrangement and a counter-pressure member, wherein the support body arrangement comprises
This provides the significant advantages of allowing for the base body and the support body being manufactured independently of each other and forming the support body arrangement by the mounting structure being provided for engaging with them and fixating them. As mentioned above, this is advantageous both in allowing for different manufacturing processes and possibly different manufacturing sites for the base body and the support body before they are mounted and also in allowing for mounting the support body arrangement on location where it is to be used in a paper machine. The handling and use of the support body arrangement is rendered more versatile and cost efficient in this way.
Suitably, the mounting structure comprises an adhesive arranged on a surface of the base body and/or on a surface of the support body such that the base body and the support body adhere to each other.
Also, the mounting structure may comprise a first portion that is fixedly attached to the support body and a second portion that is fixedly attached to the base body, wherein further the first portion and the second portion of the mounting structure are configured to engage with each other in a mounted state for mounting the support body on the base body.
Suitably, the first portion may be integrated with the support body and/or the second portion is integrated with the base body. This is beneficial in preventing undesired removal of the first portion and/or second portion and provides a secure and reliable mounting of the support body arrangement.
Also, one of the first portion and the second portion may comprise a male part and the other of the first portion and the second portion may comprise a female part, and furthermore the male and female parts are configured to mate with each other such that the support body is mounted on the base body. Thereby, a secure mounting fixating the support body in relation to the base body is achieved.
Also, one of the first portion and the second portion may comprise an inner thread and the other of the first portion and the second portion may comprise an outer thread. The inner thread and outer thread are then configured to cooperate such that the support body is mounted on the base body. This enables a stable and secure mounting so that accidental removal of the support body from the base body is prevented.
Alternatively, one of the first portion and the second portion may comprise a pin and the other of the first portion and the second portion may comprise a receiving opening for receiving the pin such that the support body is mounted on the base body. Thereby, a stable and secure mounting is also achieved.
Also, the mounting structure may comprise a gripping member that is fixedly attached to the base body, the gripping member being configured to enclose at least a part of the support body such that the support body is mounted on the base body. This allows for the support body to be applied to the base body and be held securely. In one embodiment, the gripping member may be in the form of at least two side portions that are configured to extend from the base body in the first direction at a distance from each other, so that the support body is configured to be inserted between the at least two side portions in order to mount support body on the base body. The at least two side portions may be provided as opposite side portions arranged transversally on the base body, but alternatively the side portions are arranged to enclose the support body on both transversal and longitudinal sides.
Suitably, the mounting structure may be a separate mounting body comprising a base body engagement part configured to engage with the base body and a support body engagement part configured to engage with the support body for mounting the support body on the base body. This allows for the manufacture of the support body and the base body independently of each other and is especially beneficial since the mounting structure does not risk interfering with properties of the base body or support body during manufacture. Thus, the support body and the base body may be made without having to take the mounting structure into account as long as the mounting structure is able to then mount the support body on the base body.
Suitably, the mounting structure is configured to be releasably mounted such that the support body can be removed from the base body. This allows for the removal and replacement of the support body and/or the base body as desired when worn or damaged.
Also, the support body may comprise a first material, said first material being a material that has a shore A hardness of 95 or less. Thereby, an elastically deformable support body is achieved so that the elongated nip may be realized as desired.
Suitably, the base body comprises a second material that has a shore A hardness of 90 or less. Thereby, a suitably elastic base is achieved so that the base body may be expanded and the support body continuously pressed in the first direction in order to achieve desired properties of the elongated nip.
Advantageously, the support body may be harder than the base body, i.e. have a shore A hardness of the support body that is larger than a shore A hardness of the base body. This is advantageous in allowing the base body to expand while at the same time providing a suitable pressing of the working surface into the extended nip.
In some embodiments, the support body and the base body comprise different materials. Thereby a stable and reliable base body may be combined with a flexible and elastic support body in order to achieve the benefits of having an elastic body in the elongated nip while at the same time having a flexible base body to allow extension of the base body as desired. It is also highly beneficial to be able to manufacture the support body separately from the base body, since the combination of different materials when manufacturing one combined base body/support body component is associated with considerable difficulty and requires careful control of the manufacture. To be able to achieve the benefits of both materials without having to take them into account when manufacturing the base body and the support body is therefore one of the main benefits of the present invention.
In some embodiments the support body and the base body may comprise the same material. This may then be a material that is provided in an elastically deformable and a non-elastic variety so that the desired flexibility of the base body and the desired more stable support body may be achieved. Alternatively, the support body and the base body may have similar properties or differ very little from each other. One material that is suitable for these purposes is polyurethane, which may be adapted to have desired properties regarding stiffness and elasticity, so that both more flexible bodies and more stable ones may be made from the same material but have different hardness. The manufacture of the base body separately from the support body is again highly beneficial since there are considerable difficulties associated with manufacturing one combined base/support body component using different versions of the same material.
Suitably, at least one of the base body and the support body comprises a polymer. Thereby, materials that have desired properties to serve as a support body and/or base body may be used.
In some embodiments the base body comprises a base section having the at least one pressure chamber and a top section that is arranged on the base section in the first direction, wherein the top section is preferably releasably attached to the base section. This provides the base body as a combination of two different sections that may also be manufactured separately from each other and that may be mounted to form the base body before applying the mounting structure to mount the support body, or that may alternatively be mounted by using the mounting structure for this purpose also.
The present invention also refers to a method for replacing a support body of a support body arrangement according to the invention in a paper machine having an extended nip formed between the support body and a counter-pressure member. This method comprises disengaging the mounting structure of the support body arrangement, removing the support body from the base body, providing an additional support body that comprises a working surface for forming an extended nip with a counter-pressure member of the apparatus, and mounting the additional body on the base body of the support body arrangement by engaging the mounting structure. Thereby, a support body may be replaced when damaged or worn. This enables a shorter downtime for maintenance and repair since replacing the support body may take place on site, and it also provides a cost-efficient support body arrangement since parts that are still in good working order may be retained.
Suitably, this method also comprises replacing at least part of the mounting structure before mounting the additional support body on the base body. This is advantageous since the mounting structure may itself be damaged or worn. Also, if the mounting structure comprises an adhesive, a used adhesive may be removed and replaced with fresh adhesive.
The present invention also refers to a paper machine for manufacturing paper from a pulp, the paper machine comprising at least one support body arrangement according to the invention.
Many additional benefits and advantages of the present invention will be readily understood by the skilled person in view of the detailed description below.
The invention will now be described in more detail with reference to the appended drawings, wherein
All the figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate the respective embodiments, whereas other parts may be omitted or merely suggested. Any reference number appearing in multiple drawings refers to the same object or feature throughout the drawings, unless otherwise indicated.
When referring to a “paper machine” herein, this is to be understood as a machine suitable for producing paper from a pulp. The machine may be configured to produce tissue paper but may alternatively be configured to produce writing paper or paperboard. In the following, references are made to the production of tissue paper but this is to be seen as an example only and not as limiting to the scope of the present invention.
When terms such as “upper”, “lower”, “top” and “bottom” are used in the following this is to be understood as being in relation to a first direction D that may be seen as a direction upwards. Thus, an upper side is a side that faces in the first direction D whereas a lower side faces in a direction opposite to the first direction D. Also, an upper part and a bottom part differ from each other in a movement towards the first direction D first passing the bottom part before passing the upper part.
When the terms “fixated” is used herein, or when it is described that a component is mounted or arranged so that movement in relation to another component is prevented, this is to be understood as that component being fastened or applied in such a way that independent movement of the component is prevented. Especially regarding a support body mounted on a base body, this means that the support body is reliably attached to the base body and that a movement of the base body is transferred to the support body.
In the press nip N between the extended nip roll and the counter-pressure member 7, water is pressed out of the web W and absorbed by the felt 33 which is water-receiving. The web W then passes over the Yankee drying cylinder 7 and is dried by heat propagated from the Yankee drying cylinder 7 to the web W. The Yankee drying cylinder 7 comprises internal heating symbolically identified as a heating device 8 but it is to be noted that various ways of heating a Yankee drying cylinder 7 are known, such as from within the Yankee drying cylinder or from an outside, and that each of the known ways of heating would be suitable for use with the paper machine 1 described herein. Suffice it to say that the Yankee drying cylinder 7 is typically heated to reach a temperature on a surface that contacts the web W of about 95-100° C. A dry solids content of the web W as it reaches the extended press nip N may vary considerably but is in typical applications in a range 18-30%. After the extended press nip N, the web W may have a dry solids content of 40-55%, depending on factors such as linear load in the nip, the temperature of the counter-pressure member 7 and the dry solids content of the web W before it reaches the extended press nip N.
The web W is typically doctored from the Yankee drying cylinder 7 by a doctor blade 9 and is passed in the form of a ready-dried web W to a reel-up 3.
What is said above is to be regarded as a general description of a paper machine 1, but it is especially to be noted that the support body arrangement according to the present invention may be used with various kinds of paper machines as long as they have the extended press nip between a support body and a counter-pressure member.
Thus, the flexible jacket 10 has an axial direction that coincides with the cross machine direction and at its axial ends the flexible jacket 10 is normally connected to end walls that are rotatably arranged about and axis so that the extended nip roll 5 is able to rotate. Suitably, the extended nip roll 5 may be connected to a source of pressurized air so that an enclosed space formed by the flexible jacket 10 and the end walls may be filled with pressurized air.
Inside the extended nip roll 5, a support 21 is mounted and holds a support body arrangement 50 according to the present invention such that an upper surface 14 of the support body arrangement 50 is pressed against the interior surface 11 of the flexible jacket 10. On the upper surface 14 is a working surface 15 (see
The working surface 15 is a surface that acts to form the extended press nip N. The shape of the working surface 15 may be adapted to form a desired press profile with the counter-pressure member 7, as is well known within the art. One prior art technology that deals with the design of a working surface is US 2009/0173465 (Metso paper).
Suitably, the support 21 may be configured to cover the base body 51 on every side except on a side facing in the first direction D in order to ensure that the controlled expansion is directed in the first direction D only, but alternatively the base body 51 itself may be made such that expansion of the base body 51 in other directions are not possible. Since the support body 52 is mounted to extend from the base body 51 in the first direction D, an expansion of the base body 51 will result in the support body 52 being pushed in the first direction D and when the support body arrangement 50 is in place inside the extended nip roll 5 this results in the support body 52 being pressed against the interior surface 11 of the flexible jacket 10 so that the extended press nip N is formed. When the extended nip roll 5 is used, the extended press nip N is to be seen as being a closed nip when the working surface 15 of the support body arrangement 50 is pressed against the flexible jacket 10, i.e. when the at least one pressure chamber 18 is pressurized so that the base body 51 is expanded in the first direction D. When the base body 51 is not expanded, the extended press nip N is instead to be seen as being open.
It is to be noted that the at least one pressure chamber 18 may in some embodiments be provided underneath the base body 51 instead of inside the base body 51, as long as the at least one pressure chamber 18 is able to press against the base body 51 to achieve the extension in the first direction D.
In an extended press nip, a pressure profile should be unsymmetrical in such a way that a pressure peak is achieved shortly before an end of the press nip and so that pressure is significantly reduced immediately after the pressure peak. Such a pressure profile reduces re-wetting of the paper web W. It is also desirable that a pressure gradient at a beginning of the nip is relatively small such that the pressure is increased gently but with a larger gradient thereafter until the peak is reached towards the end of the press nip. Depending on properties of each application where an extended press nip is used, the upper surface 14 of the support body 52 may be adjusted to modify the pressure profile of the nip. In
The support body arrangement 50 will now be described in more detail with reference to
The word fixated is, as also mentioned above, to be understood as meaning a holding of the support body 52 and the base body 51 that prevents them from moving independently of each other. Thus, the support body 52 being fixated to the base body 51 means that the expansion of the base body 51 is transferred to the support body 52, while at the same time preventing such expansion of the base body or movement of the support body that results in a translational movement of one of them but not the other.
The various embodiments of the present invention also share the main advantages, namely the benefit of being able to manufacture the base body 51 and the support body 52 separately from each other and joining them together at a later time. This is a significant improvement over the prior art and allows for a simplified manufacturing of the support body arrangement 50 as well as a more versatile support body arrangement 50 that may be more easily modified to adapt to different applications and more cost efficient repair of support body arrangements 50 when in use.
Thus,
Manufacture of the support body arrangement 50 of the first embodiment is performed by providing 101 the base body 51, providing 102 the support body 52 and providing 103 the mounting structure 53 by applying the adhesive of the mounting structure 53 to at least one of the upper surface 51′ of the base body 51 and the lower surface 52′ of the support body 52. The support body 52 is then mounted 104 on the base body 51 such that the upper surface 51′ of the base body 51 is in contact with the lower surface 52′ of the support body 52. Due to the adhesive of the mounting structure 53 being able to engage both with the lower surface 52′ of the support body 52 and the upper surface 51′ of the base body 51, the mounted state is formed with the support body 52 being fixated on the base body 51. In an optional step, the support body 52 may also be removed 105 from the support body arrangement 50 when desired.
Suitably, the side portions 531, 532 are joined to each other at a bottom section 533 and form a side portion holder 534 such that the base body 51 and the support body 52 are placed inside the mounting structure 53 between the side portions 531, 532 in the mounted state with only an upper part of the support body 52 protruding beyond the side portions 531, 532 in the first direction D. Also, further side portions may be provided at ends of the base body 51 (not shown) so that the base body 51 may be inserted into the side portion holder 534 with only the upper surface 51′ being visible. Alternatively, side portions may be provided on three sides of the base body 51 so that one side is left exposed. In embodiments where side portions are provided on four sides of the base body 51, conduits for supplying the pressurized medium may be provided in one of the side portions and be connected to the at least one pressure chamber 18 during mounting.
The side portion holder 534 may be integrated with the holder 21 shown in
In an alternative embodiment, the mounting structure 53 may instead comprise a gripping member that is fixedly attached to the base body 51 and that is configured to grip or enclose at least a part of the support body 52 such that the support body 52 is mounted on the base body 51. The gripping member than fulfils the same function as the side portions 531, 532 in being able to hold the support body 52, and it may be realized through the gripping member being fastened on the base body 51 in a way similar to the side portions 531, 532 so that the support body 52 is fastened by the gripping member enclosing sides of the support body 52 and gripping them to hold the support body 52 in place.
For this embodiment in particular, the base body 51 may be very soft and flexible since it may be held in the holder so that expansion of the base body 51 in any direction other than the first direction D is efficiently prevented. The base body 51 may comprise an elastomer that has a shore A hardness of below 50 or even below 30 and may suitably comprise rubber. An expansion due to action of the pressure chambers 18 may thereby be transferred efficiently to the support body 52 mounted on the base body 51.
Manufacturing the support body arrangement 50 according to the second embodiment is performed by providing 101 the base body 51 and providing 102 the support body 52, and also by providing 103 the at least two side portions 531, 532 or alternatively the side portion holder 534 of the mounting structure 53. The base body 51 is then placed between the at least two side portions 531, 532 and the support body 52 is mounted 104 on the base body 51 such that it may be held in place by the at least two side portions 531, 532. The main feature of the side portions 531, 532 that enable them to hold the support body 52 in place is their extending from the base body 51 in the first direction D, such that the support body 52 will be unable to move in a direction in which a side portion 531, 532 is provided. In an optional step, the support body 52 may also be removed 105 from the support body arrangement 50 later, as desired.
In embodiments where only the two side portions 531, 532 are provided, these side portions 531, 532 may alternatively be mounted on the base body 51 such that they are fastened to the base body 51 or alternatively that they are integrated with the base body 51. In such embodiments, the base body 51 and the side portions 531, 532 of the mounting structure 53 may be provided as a single component. The support body 52 is then placed on the base body 51 so that the side portions 531, 532 hold the support body 52 fixated in relation to the base body 51 to form the mounted state.
If the adhesive is used, it may be applied to the base body 51 and/or the support body 52 before the base body 51 is placed between the side portions 531, 532 or alternatively the adhesive may be added when the base body 51 is in place between the side portions 531, 532 but before the support body 52 is added.
In the third embodiment of
In the third embodiment shown by
In another embodiment, one of the first portion 536 and the second portion 535 may instead comprise an inner thread and the other of the first portion 536 and the second portion 535 may comprise an outer thread that are configured to cooperate with each other such that the support body 52 on which the first portion 536 is fastened is able to be screwed into place on the base body 51 on which the second portion 535 is fastened.
Alternatively, one of the first portion 536 and the second portion 535 may comprises a pin and the other of the first portion 536 and the second portion 535 comprises a receiving opening configured to receive the pin such that the support body 52 may be mounted on the base body 51 by the pin being inserted into the receiving opening.
For each of the versions of the third embodiment it is to be noted that the support body 52 may be provided with a plurality of first portions 536 and the base body 51 may be provided with a plurality of second portions 535 and that manufacturing the support body arrangement 50 then comprises bringing each of the first portions 536 to interact with at least one of the second portions 535.
The manufacture of the support body arrangement 50 according to the third embodiment shown in
The third embodiment and any variations on the third embodiment are also suitable for combination with the first embodiment, i.e. with providing an adhesive that further assists in fixating the support body 52 on the base body 51. Suitably, the adhesive may be applied to at least one of the first portion 536 and second portion 35 such that the first portion 536 and the second portion 535 are attached to each other by means on the adhesive during mounting.
In a fourth embodiment, the mounting structure 53 may be a separate mounting body that is placed between the base body 51 and the support body 52 during manufacture of the support body arrangement 50. The mounting structure 53 in this embodiment has a base body engagement part for engaging with the base body 51 and a support body engagement part for engaging with the support body 52. The base body engagement part and the support body engagement part may be of any of the types shown for the first portion 536 and the second portion 535.
One important benefit of the present invention is that the support body 52 may be releasably fixated to the base body 51 during mounting so that the support body 52 may be released again from the support body arrangement 50 at a later time. When providing the mounting structure 53 in the form of a male and female part, as inner and outer threads, or as keyway and key or pin and receiving opening, or variations thereof, this is most conveniently realized by the first portion 536 and second portion 535 being configured to disengage. This may take place by the threads being screwed in an opposite direction, by the pin being pulled out of the opening or by the male and female part being separated such as the key being slid out of the keyway for instance. This is especially advantageous in enabling the removal of the support body 52 as desired, such as when the support body 52 has been worn by pressing against the flexible jacket 10 of the nip roll 5 during operation of the paper machine 1. Since the profile of the working surface 15 is so important in achieving the desired extended nip, it is especially beneficial to be able to remove the support body 52 and replace it with a new unworn support body 52 if performance decreases. Also, depending on the paper machine 1 and the paper that is to be manufactured, it may be needed to change the pressure profile in the extended nip and this is most conveniently done by replacing only the support body 52 and using the same base body 51 to form a new support body arrangement 50. This is especially time saving since it allows for connections to the pressure chamber(s) 18 to remain in place, and in embodiments of the support body arrangement 50 where the support body 52 is easily removable such as variants of the third embodiment and the second embodiment, the downtime of the paper machine may be kept to a minimum.
The support body 52 of the support body arrangement 50 preferably comprises a first material that has a shore A hardness of 95 or less. This is advantageous in providing the extended press nip N to dewater the web W as desired. Examples of such material that are suitable for use in the support body 52 are polymers, suitably polyurethane or an elastomer such as rubber. In some embodiments, the support body 52 may comprise more than one material and it is advantageous that at least one of the materials has a shore A hardness of 95 or less.
Also, the base body 51 suitably comprises a second material that has shore A hardness of 90 or less. The second material is suitably elastically deformable and thus provides a base body 51 that is able to undergo the controlled expansion due to the expansion of the pressure chamber(s) 18. The second material may suitably be a polymer such as polyurethane or an elastomer such as rubber. The base body 51 may in some embodiments comprise a plurality of materials but may in other embodiments be made from only one material.
It is advantageous if the support body 52 is harder than the base body 51, i.e. if the support body 52 has a higher shore A hardness than a shore A hardness of the base body 51. This enables the base body 51 to expand as desired, while at the same time providing a more stable support body 52 that is able to provide a desired pressure profile in the extended nip. In some embodiments, the support body 52 may have a shore A hardness of 90-95 while the base body 51 has a shore A hardness of as low as 30-50. In other embodiments, the support body 52 and the base body 51 differ less from each other with regard to hardness of the materials.
When mentioning shore A hardness herein, this is to be understood as being according to ASTM D2240.
In some embodiments, the base body 51 and the support body 52 may comprise the same material. One material that is suitable for this is the aforementioned polyurethane that may be designed to have suitable properties for hardness.
In some embodiments of the present invention the base body 51 may be made from a plurality of parts, suitably a base section that comprises the at least one pressure chamber 18 and a top section that is arranged on the base section and faces in the first direction. In such embodiments, the top section may be releasably attached to the base section, but alternatively the top section may be joined to the base section in a permanent way so as to be non-removable. In yet other embodiments, the support body 52 may instead be made from a plurality of parts that are joined together in a releasable or permanent way.
The method for replacing the support body 52 of the support body arrangement 50 according to the invention will now be described. This is suitable in situations where a support body arrangement 50 is used in a paper machine 1 and has been subjected to wear or damage such that the extended press nip N no longer provides the desired pressure profile to the web W passing the nip. Also, the support body arrangement 50 may have been in use for its intended lifetime and is scheduled for exchanging the support body 52 in response to this.
Thus, the support body arrangement 50 according to any of the embodiments of the invention is provided in a paper machine 1. In most situations, the support body arrangement 50 would be removed from the paper machine 1 in a way that is well-known in the art before the support body 52 is replaced, but in some situations it is desirable for time and cost efficiency purposes to maintain the support body arrangement 50 in place during maintenance since the downtime of the paper machine 1 is shortened.
The method for replacing the support body 52 comprises removing 202 the support body 52 from the support body arrangement 50 by disengaging 201 it from the mounting arrangement 53 and/or from the base body 51 depending on which embodiment of the support body arrangement 50 is being used. The disengaging 201 of the support body 52 may thus comprise disengaging the first portion 536 and the second portion 535 or alternatively the removal of the support body 52 form the side portions 531, 532. It may also comprise removing or disengaging the adhesive so that the support body 52 is no longer fixed to the base body 51.
When the support body 52 is released, it is then removed 202 from the base body 51 and an additional support body 52 is provided 203. The additional support body 52 is then mounted 204 on the base body 51 by engaging with the mounting structure 53 in the same way that the support body 52 did or in a modified way such as adding an adhesive to the mounting structure 53 even if the mounting structure 53 previously lacked an adhesive.
The mounting structure 53 may be replaced 205 if it is not able to engage again, such as if the removal of the support body 52 has damaged the mounting structure 53 or if the mounting structure 53 is not designed to be able to be used more than once. If the mounting structure 53 comprised the adhesive before the support body 52 was removed, it is suitably replenished with fresh adhesive to be able to fixate the additional support body 52.
The adhesive may suitably be a polyurethane one-component moisture curing adhesive such as Liquisole/Rubberfix provided by Casco. However, many other types of adhesives may alternatively be used, as is well known to the skilled person.
The additional support body 52 may be identical to the support body 52 or may differ in some way, such as comprising different material in order to have different material properties such as elasticity, or may alternatively have a working surface 15 of a different profile. The additional support body 52 should be similar to the support body in being able to interact with the mounting structure 53, however, such that the additional support body 52 is able to be mounted on the base body 51.
It is to be noted that features from the various embodiments described herein may freely be combined, unless it is explicitly stated that such a combination would be unsuitable.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2051422-0 | Dec 2020 | SE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/082582 | 11/23/2021 | WO |
