FI119521B - Fiber web machine roller - Google Patents

Description

119521

FIELD OF THE INVENTION The present invention relates to rolls of fiber web machines such as paper or board machines. More particularly, the present invention relates to a fiber web machine roll according to the preamble of claim 1.

In fiber web machines, one type of roll using load elements, i.e., each is a deflection compensated roll, comprising: a stationary roll shaft having a loading cavity for a pressurized medium and a loading arrangement such as a loading shoe, and being rotatably rotated about the roll axis; an internal loading arrangement which is loaded radially in the loading cavity towards the inner surface of the roll shell; wherein the loading arrangement 15 has recesses open towards the inside surface of the roll shell, which form chambers with the inside surface of the roll shell to which a pressurized medium is introduced. Deflection, ·,: Compensated rolls are commonly used as nip rolls. The previously known so-called. • • · • · handlebars are usually hydraulically deflection compensated zone adjustable •:. *. rolls supporting and shielding the diaper from a non-rotatable center roll »: 20 from the back with a hydrostatic loading arrangement such as a load shoe row.

·· «· i: *; The load shoe row is also generally divided into zones, whereby the load ···; ***: pressure can be adjusted in the transverse direction of the web, i.e. MD direction, i.e. in the CD direction according to the need for profiling. The zone division of such a zone-adjustable shoe roll can be divided into individual load ·· * · # ιφϊ 25 packing elements, which can increase the number of zones in the roll loading arrangement to more than 60 - examples include the applicant's trademarks • · · ***: SymCD ™ and SymCD ™ shoe rollers, or a set of load adjuster • · · elements, whereby the roller and load adjuster normally have • • •. ···. Dexa Zone - Examples include: · ··· 30 shoe rolls marketed by SymZ ™, SymZS ™, SymZL ™ and SymZLC ™. The deflection compensated rolls use cast groove diapers and lead shoe bronze as a material for the shoe sliding bearing. In some applications, there has been a need to use steel diapers. Lead-bronze sliding shoes with steel liners have proved problematic because these materials are not well suited for contact with one another and the inner surface of the liner may have been rendered unusable by the clipping of the shoes. The glide bearing material must be wear resistant, non-slip to the surface, strong enough to withstand fatigue, and capable of absorbing hard particles to some extent. To achieve these goals, the sliding surface may have been coated with a polymeric material.

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Another type of roller in fiber web machines using a loading element, i.e. the shoe, is a long nip roll comprising a shaft portion supporting a stationary compression shoe and two end plates which are rotatably supported on the shaft portion and an elastic sheath surrounding the shaft portion , that the diaper rotates with the end plates so that each zone of the diaper slides in turn against the pin of the press shoe, ·. · Over nan. Long nip rolls are used, for example, on the press section of the paper machine and • · · ··. ·. calendering. In the compression zone of the long nip press or calender, • · • *:. ·. the elastic sheath of the nipple roller is forced to slide into contact with the press roll ΙΦ * ·: 20 with the shoe. One problem with long nip presses is the variety of models · »* ·. due to belt damage. In memory, the gasket between the strap and the shoe is broken, causing a high shear tension on the strap and a distortion of the strap, which can also cause damage to the back roll. In such a situation, the shoe will often be damaged and will have to be replaced completely.

(j 25 For this reason, the friction between the shoe and the strap must be small for the shoe to function *. V. also in the borderline situations described above.

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Arrangements are known in the art for solving the above-described problems by: list · placing a molding structure consisting of a »» 30 molding across the nip at a nip. The disadvantage of these, however, is that the structure is step-shaped, which is not suitable for use in all types of shoe needs of fiber web machine rolls, such as long nip rolls. This type of glacial fluid is described, for example, in U.S. Patent No. 6,045,492.

On the other hand, problems have also been solved by coating the inner surface of the jacket with a suitable material. However, this may be problematic from a manufacturing technique and is also not suitable for use with all types of fiber web machine roll shoe needs, such as long nip rolls. One such is described in U.S. Patent No. 5,785,636.

EP-A-1 394 424 describes an arrangement in which the entire upper part of the shoe between the support structure and the counter surface or the upper part of the shoe with the supporting structure is made of plastic. However, this is a relatively expensive arrangement which may be insufficient in rigidity in applications requiring high rigidity.

DE DE 196 07 144 discloses a long nip press. Long Neck Wear ·. · The cross member has a load shoe supported by a stationary shaft, rotated by a belt • hoop. A separate, removable metal plate is mounted on the load shoe surface facing the inner surface of the strap. Me- »» · · J. *. The purpose of the 20 stables is to provide a homogeneous press surface for the load.

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It is a primary object of the present invention to provide a roll of a fiber web machine in which the above-mentioned problems can be eliminated or at least substantially reduced.

In order to achieve the foregoing and further objects, the roller according to the invention is essentially characterized by what is stated in the present invention. ·, In the characterizing part of claim 1.

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The invention thus provides an interchangeable wear part, in which the wear element of the load element / shoe is either completely or interchangeable and the wear part is made at least of a surface material towards the nip made of a plastic material.

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In accordance with a preferred embodiment of the invention, the body of the shoe / load element is provided with an easily replaceable wear member in the event of damage.

In the context of the invention, the slip-bearing material of the shoe of a fiber web machine is made of advanced thermoplastic (Advanced Engineering Plastic), for example polyetherketone (PEEK), polyamideimide (PAI) or polyimide (PI), in order to improve. The new advanced thermoplastics have good abrasion resistance properties, they do not cut on the steel surface and they are somewhat malleable, so they can withstand the edges of the shoe well, and in addition · any particles can sink into them. They are not very good in rigidity and therefore the structure preferably comprises a rigid support member made of:. for example steel. The replaceable wear part according to the invention is thus a soli · · · i · · · i. 20 Gold bearing material secured with possible stiffeners ♦ ·· ·. interchangeably with the rest of the shoe structure through the nozzle «a» · ** '· of the shoe loading elements. This arrangement also has the advantage that expensive plastic material is required only for the sliding bearing member and that the stiffener member is made of a lower cost material, e.g. metal, preferably cast iron or steel, or fiber reinforced polymer composite. For example, screws and gluing or riveting to each other are provided.

In connection with the invention, the shoe has a strap-on portion of a plastic material whose friction against the strap at the limit lubrication situation is substantially less than that of the steel or other metallic material used today. The plastic part can be uniform over the entire width of the shoe or made of parts, so that in the event of a damage, only the damaged part can be replaced. Preferably, the part is secured to the body by salmon tail attachment, screw or other suitable means. The portion-5 has a thickness of at least 5 mm.

The replaceable member extends from the upper surface of the shoe starting from the contact pad to at least the pressurized area, but the replaceable wear member can also extend to the entire upper surface area.

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An added benefit of plastic over steel is that there is less damage to the back roll in the Vau-riot case, where the shoe rubs against the back roll. A further advantage of plastic is that the plastic acts as a heat insulator to prevent frictional heat from being transferred to the metal body of the shoe, which prevents thermal deformation of the shoe, which otherwise could cause profile problems.

. . The material of the load cell / shoe is otherwise typically made of metal, • · * such as aluminum, steel, aluminum bronze.

The invention will now be described in more detail below by some of its preferred embodiments. . ·. Embodiments of the invention by reference to the accompanying patent drawings, each of which is incorporated by reference. * * *. however, the invention is not intended to be narrowly limited in detail.

··· · * · "Figure 1 schematically shows a prior art long nip * 25 cross.

··· m φ • · · • · ®. ···. Fig. 2 schematically shows a prior art deflection roller.

3A-3B schematically illustrates an embodiment of the invention in connection with a long nip roll.

6 119521

Figures 4A-4C schematically illustrate an embodiment of the invention for a deflection compensated roll.

5 Unless otherwise stated, like reference numerals are used to refer to like parts.

Fig. 1 schematically illustrates a prior art long nip press comprising a long nip roll 1 and a counter roll 2 forming between them an elongated press nip N through which a paper or board web is guided to pass by a press fabric (not shown). The long nip roll 1 comprises a stationary shaft portion 3 of which only a portion is shown in the figure. It supports a press shoe 5 and a load member 4 for pressing the press shoe S against the counter roll 2 to achieve the desired press pressure. The shaft portion 3 is surrounded by a resilient tubular jacket 10 attached to each end plate 11 of the roll (for reference only). The end-plates 11 are mounted for rotation of the shaft part 3 in a horizontal position. stream. As the sheath 10 rotates about the shaft portion 3, each zone slides in turn • · · • · ♦.! / over the surface of the clamping shoe 5.

Fig. 2 shows a prior art deflection-compensated roll, *. . ·. comprising a casing 10 rotating about stationary axis 3 to form t · • · ·. ···. in conjunction with the outer surface of the counter roll 2, a nip N in which the nip load tends to cause deformation of the casing 10. A load arrangement is provided between the stationary shaft 3 and the roll casing 10, comprising a hydraulic row of loading pistons. 4, which may be several tens of rolls, to compensate for the roll • · ·, vt and to load the roll jacket against the back roll.

φ · · * ·. · · ·. A stationary shaft 3 is provided with a hydraulic • · * ··, · for each loading piston 4. a roller loading cavity 4 'fed with a pressurized medium, preferably hydraulic oil, through a feed channel 15. Each load piston 4 may have its own pressure supply channel 15. The pressure medium may be introduced into the roll through, for example, the central bore 15 * of the stationary shaft 3. Through the supply channel 15, the pressurized fluid 7119521 is introduced into the loading cavity 4 'for moving the loading element 20 radially relative to the axis 3. The loading element 20 is comprised of a loading piston 4 and one or more sliding elements 5 substantially connected therewith by the pressure 5 applied by the hydraulic medium to the loading cavity 4 ', the loading element 20 being loaded against the sliding surface 10 of the sliding element 5 A lubricant film is formed between the sliding surface and the inner surface of the jacket 10 by passing a pressure medium through the loading element 20 into the recesses 22 on the sliding surface of the capillaries 15 'which form the lubricating chambers. The lubricating-10 chambers 22 are located separated by the bases 16 and may be several in the CD direction in succession.

Figures 3A-3B illustrate an embodiment of the invention in connection with a long nip roll.

Figure 3A shows an extended nip formed by a long nip roll and a counter roll 2

15 N. The shoe of the long nip roll is pressed against the counter roll 2 at the desired nip pressure P

on the inside of the elastic sheath 10, i.e. the belt 10. Shoe 5 . the lubricating medium is guided along the blocked passage 15 to the surface of the shoe 5 in a fluid-tight recess for lubricating the 22 nip Ns. 3A-3B, as shown in FIGS. ! the shoe 5 is provided with an interchangeable wear member 30. The wear member 30 is disposed within the embedment of the shoe 5 and is disposed so as to extend into the shoe. . ·. 5 against the inner surface of the resilient sheath 10 at least on the area facing it, · · · ··. ···. where nip pressure P is applied. The wear member 30 against the inner surface 10 of the belt 10 is preferably made of a plastics material whose friction against the belt 10 is limited to a limit ί *. • be uniform across the entire width of the shoe • * · t / .t 5 or in the CD direction, so that in the event of damage, only the damaged part can be replaced. The size of the wear member 30 is at least 5 mm The body material of the lubricating member 30 is, for example, a metal such as aluminum, steel. As shown in Fig. 3A, the replaceable wear member extends from the contact surface of the shoe 5 8 119521 to at least the pressurized area P m The replaceable wear member 30 can also extend over the entire upper surface area.

Figures 4A-4C schematically illustrate an embodiment of the invention for a deflected roll 5. The loading element 20 comprises a surface portion 32, i.e., a sliding bearing member and a support portion 31. The loading element 20 is secured to the loading piston 4 via nozzles 17 having fluid passages or capillaries 15 'within the nozzles 17. The surface portion 30 of the loading element 20 acts as a sliding bearing. Preferably, the surface portion material is an advanced thermoplastic, for example polyether-ketone (PEEK), polyamideimide (PAI) or polyimide (PI), preferably slightly doped with polytetrafluoroethylene (PTFE) and / or graphite to improve gliding properties. In order to increase rigidity, the replaceable wear member comprises, in this embodiment, a rigid support member 31 made of metal, for example steel or composite. The replaceable wear member 30 is thus a sliding bearing material 15 which is removably attached to the rest of the shoe structure by means of nozzles 17, for example. Convertible expense. . the support member 31 and the slide bearing member 32 of the base member 30 are secured to each other, for example, by screws and gluing or riveting.

The invention has been described above only with reference to some of its preferred applications, which. ·. However, the invention is by no means strictly limited to the details. this.

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Claims (11)

A roller for a fiber web machine, said roller comprising a load member or shoe (5; 20), said roller (1) being a roller forming a nip (N) together with a counter roll (2) and in the nip being the nip pressure ( P) arranged to be accomplished by mediating a load piston (4) arranged in conjunction with the shoe (5; 20), the shoe (5; 20) of the roller comprising an interchangeable wear portion (30) arranged on the nip (N) the surface of the shoe (5; 20) and the wear portion (30) extending over at least the area of the surface of the shoe (5; 20) approaching the nip (5; 20) on which the nip pressure (P) acts, characteristic - the fact that the interchangeable wear portion (30) of the shoe (5; 20) in the roller at least at the surface portion approaching the nip (N) is made of plastic material. 2. A roller for a fiber web machine according to claim 1, characterized in that the plastic material of the interchangeable wear part (30) of the shoe (5; 20) in the roller is a developed thermoplastic, for example polyether ketone (PEEK), polyamidimide (PAI) or polyimide ( PI). t 3. A roller for a fiber web machine according to claim 1 or 2, characterized in that the plastic material of the interchangeable wear portion (30) of the shoe (5; 20) in the roller * · • · · j *:: is mixed with a little polytetrafluoroethylene (PTFE) and / or graphite. • * * • * · ··· · * · · 4. A roller for a fiber web machine according to any of claims 1-3, characterized in that the interchangeable wear portion (30) of the shoe (5; 20) in the roller is adhered to. . The body of the shoe (5; 20) with a salmon tail dressing. * · I 5. A roller for a fiber web machine according to any one of claims 1-4, characterized in that the interchangeable wear part (30) of the shoe (5; 20) in the roller is connected to one another. • · in the CD direction of the fiber web machine. • · *: V 30 φ · • · · • ·· • · 119521 Roll for a fiber web machine according to any of claims 1-5, characterized in that the interchangeable wear part (30) of the shoe (5; 20) in the roll consists of several parts in the CD direction of the fiber web machine, which parts are interchangeable separately. 5 Roll for a fiber web machine according to claim 1, characterized in that the replaceable wear portion (30) of the shoe (5; 20) in the roll comprises a surface portion (32) made of plastic material and a support portion (31) which is made of metal. 10 Roll for a fiber web machine according to any of claims 1-7, characterized in that the interchangeable wear part (30) of the shoe (5; 20) in the roll is fixed to the other shoe construction by means of the nozzles (17). 9. A roller for a fiber web machine according to any one of claims 1-8, characterized in that the surface portion (32) and the support portion (31) of the interchangeable wear portion (30) of the shoe (5; 20) in the roller are secured to each other by screws , by gluing or by riveting. • ♦ • · · • · · • t ·· 1 I .1 20 10. A roller for a fiber web machine according to claim 1, characterized in that the roller is a long nip roller (Fig. 1). • · • · · • · ♦ • · · • · · ** j · 1 11. Roll for a fiber web machine according to claim 1, characterized in that the · · ··· roll is a bend-compensated roll (Fig. 2). 25 • ♦ · • · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·