Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
  • D21G1/00—Calenders; Smoothing apparatus
  • D21G1/0073—Accessories for calenders
  • D21G1/008—Vibration-preventing or -eliminating devices
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
  • D21G1/00—Calenders; Smoothing apparatus
  • D21G1/02—Rolls; Their bearings
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C13/00—Rolls, drums, discs, or the like; Bearings or mountings therefor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F15/00—Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
  • F16F15/10—Suppression of vibrations in rotating systems by making use of members moving with the system
  • F16F15/12—Suppression of vibrations in rotating systems by making use of members moving with the system using elastic members or friction-damping members, e.g. between a rotating shaft and a gyratory mass mounted thereon

Definitions

• the invention relates to a damping arrangement for damping mechanical peripheral vibrations and beam-like vibrations in a roll in a paper or board machine, which roll comprises an essentially rigid shell.
• peripheral vibration is today as serious a problem in respect of the runnability of a paper or board machine as the other type of mechanical vibration of rolls, i.e. longitudinal, beam-like vibration of rolls.
• the roll shell of the paper and board machines is manu- factured by casting or by bending from a steel sheet.
• the shell is rounded by machining and, if required, it is provided with machined grooves and coated.
• the rolls lack a special damping against vibrations, but instead damping is simply based on the inherent characteristics of steel or casting.
• the composition on the roll surface is not involved in damping of vibrations, but damping of vibrations takes place elsewhere. If it is desired to minimize the vibration, particularly in the nip, the surface material of the roll does not actually have any significance.
• the obj ect of the present invention is to provide a damping arrangement , which can be used to create efficient damping particularly for the two above-mentioned mechanical roll vibration types, i . e . beam-like vibration of a roll and peripheral vibration of a roll .
• the damping arrangement additionally includes at least one essentially rigid internal shell and a damping structure arranged between the shell and the internal shell, of which the internal shell is arranged at a distance from the shell inner surface in the radial direction of the roll and which is es sentially concentric with the shell , and the outermost surface of the damping structure is arranged immobile in relation to the shell inner surface and the innermost surface of the damping structure is arranged immobile in relation to the outer surface of the inner shell , whereby the forces produced during the roll vibration by the movement differences between the shell and the inner shell will convert, in the damping structure, to shearing forces , which will essentially be extinguished in the damping structure .
• the damping arrangement according to the invention thus com- prises two essentially rigid shells and a vibration-damping structure arranged between them.
• the damping structure can be composed of a vibration-damping material, whose rigidity characteristics are essentially lower than those of the roll shell and the inner shell.
• a damping element which comprises an essentially rigid inner shell and a vibration-damping damping layer to be arranged on the outer surface of the inner shell, and to further install this damping element as a whole inside the roll to be damped.
• An important aspect in the solution according to the invention is both a maximum possible rigidity of the roll shell and the inner shell and also a rigidity difference be- tween the roll shell and the inner shell so that the rigidity of the shell is higher than the rigidity of the inner shell. This provides maximum shearing forces between the shells in relation to the movements of the shells.
• the invention is also characterized in that the inner surface of the damping element, i.e.
• the inner shell is also rigid and continuous.
• the inner shell should thus be stiff so that the deformations will take place specifically in the vibration-damping material.
• the task of the damping material, not of the shells, is to yield and extinguish the shearing stresses.
• Another important aspect of the invention is a maximum thickness of the damping layer. That is, a maximum possible distance in the roll radial direction between the shell and the inner shell is aimed at. Namely, it has been discovered that the thickness of the damping layer correlates directly with the capability of the damping element to damp vibrations. This is due to the fact, among others, that the greater the mutual distance between the shells in the roll radial direction, the greater are the movement differences between them during the roll vibration. When the movement differences are great, me- chanical stresses will also increase between the shells connected through the damping layer. The stresses again will produce shearing stresses in the damping layer. In the damping layer these rapidly reverting shearing forces are extinguished and thus the vibration movements of the roll are damped.
• the damping characteristics are directed in the damping layer in such a manner that maximum damping is achieved in the longitudinal direction of the roll as well as in the tangential direction of the roll periphery. More pre- cisely, the rigidity of the damping material is highest both in the roll longitudinal direction and in the tangential direction of the roll periphery.
• rubber has turned out to be the best possible damping material in the damping layer.
• other materials can also be applied in the solution according to the invention.
• polyurethane which is light and has high internal friction, is well applicable as the material of the damping layer.
• Various elastomers can also be used.
• the damping element can be formed preferably complete even before bringing it inside the roll to be damped.
• the damping layer is first attached on the outer surface of the inner shell, the outer surface of the damping layer is subjected to a treatment for fastening to the inner surface of the outer shell, and finally the thus formed damping element is guided to inside the roll, where the attachment of the outer surface of the damping layer to the inner surface of the shell takes place.
• the damping elements can be adapted as complete directly to the inner surface of the shell.
• the damping arrangement according to the invention can be easily adapted for rolls of various sizes. This kind of module structure has advantages particularly in the case of old rolls. On the other hand, the arrangement can be adapted in all nip rolls and process rolls.
• Figure 1 is a cross sectional view of the roll equipped with a damping arrangement according to the invention
• Figure 2 is a sectional view of the roll of Figure 1 along the cutting line A-A
• Figure 3 is a cross sectional view of another embodiment of the roll equipped with a damping arrangement according to the invention
• Figure 4a is a sectional view of the roll of Figure 3 along the cutting line B-B
• Figure 4b is a partial enlargement of Figure 4a
• Figure 5a shows a modification of the damping structure of Figure 4a
• Figure 5b is a partial cross sectional view of the structure of Figure 5a
• Figure 6 illustrates the manufacturing method of the inner shell of the roll according to the invention.
• FIG 1 is a cross sectional view of roll 1, in which vibration damping is arranged using the damping structure 4 formed by the inner shell 3 and the damping layer 4 ' .
• the damping structure can be a damping element 13, adapted to the dimen- sions of the roll 1 to be damped, which can be guided to inside the roll 1 as a whole.
• the outer surface of the damping layer 4' is forced against the inner wall 10 of the shell 2 applying sufficient force, for example, by means of the turnbuckle screws 6 indicated in Figure 1, for fastening. This is better illustrated in the sectional view of the roll 1 shown in Figure 2.
• the surfaces of the damping layer 4' and the inner shell 3 are attached to each other in an immobile manner. The surfaces can be attached for example by gluing or by vulcanizing. After stretching the inner shell 3 it is locked in form for example by a longitudinal weld 7.
• Both the shell 2 and the inner shell 3 should yield as little as possible.
• the shell 2 and the inner shell 3 tend to bend according to the vibrations, but in a different way due to their different structures.
• the shearing forces generated by the stresses caused by the movement differences are conducted to the damping structure 4, where they are eliminated and vibration is thus damped. Damping of vibrations of the roll 1 is the best, when the distance between the shell 2 and the inner shell 3 in the radial direction of the roll and thus their mutual movement differences are as great as possible.
• damping essential is thus the thickness of the damping layer, and maximization of it is aimed at. This is exactly for achieving a great movement difference between the shell 2 and the inner shell 3.
• the ratio of the thickness of the damping layer 4 ' relative to the thickness of the shell 2 is preferably 6 - 60%, more preferably 30 - 50%.
• the optimized thickness of the damping layer 4' is 50 mm.
• Another important aspect in the damping arrangement is a high rigidity of the shell and the inner shell as well as a rigidity difference between the shell and the inner shell. This provides maximum shearing forces between the shells when the roll tends to vibrate.
• the ratio of thickness of the inner shell 3 and the shell 2 is of class 1 - 10%, preferably 3 - 6%.
• the thickness of the shell 2 is arranged at 120 mm and the thickness of the inner shell 3 is 5 mm.
• the aim is to preferably optimize the damping characteristics of the damping layer 4 ' as regards both the peripheral vibration and the beam-like vibration. This is considered also when forming possible holes or openings in the damping layer.
• a net-like structure is aimed at for the damping layer.
• the holes as for their shape and size, are arranged so that the rigidity of the damping layer is the highest precisely in the longitudinal direction of the roll and in the tangential direc- tion of the roll periphery. With this it is possible to maximize the capability of the damping layer to damp vibrations in these directions.
• the rubber mat forming the damping layer 4' is provided with holes 5, which extend through the entire damping layer 4' in this embodiment.
• the actual purpose of the holes 5 is to reduce the mass of the damping layer. It is remarkable that the mass of the damping material has no significance as regards the damping efficiency itself.
• damping element If only one continuous damping element is located in the roll, it should extend essentially over the entire roll length as shown in Figure 1. This provides efficient damping of vibrations.
• the inner shell 3 is open at the ends and detached from the head components of the roll 1. It is, however, also possible to use two or more separate damping elements inside one roll, extending over the roll longitudinal direction only for a part of the distance. In this case damping is directed particularly to the peripheral vibration. If several elements are used that extend only for a part of the distance in the longitudinal direction of the roll and that are essentially detached from one another, each element damps vibration within its specific frequency range. Thus each element can be arranged, if desired, to damp within exactly a specific frequency range.
• Damping will of course, in this case, too, be directed to the beam-like vibration of the roll, but damping is not, however, as efficient. If it desired to achieve efficient damping of the beam-like vibration when using several damping elements inside one roll, the elements must be arranged continuously attached to each other.
• the damping element can be ready cast to the shell even at the mounting site. It should also be noted that in the arrangement according to the invention the installation of the damping layer and the inner shell inside the roll can be naturally carried out even in completely different stages.
• balancing is carried out by arranging the balancing elements to the sides of the damping element/s.
• balancing is today carried out by means of a polyurethane composition.
• a polyurethane composition is cast on the inner surface of the roll shell a quarter of the roll at a time using a net grid.
• balancing nets and the polyurethane composition could be replaced with for example two damping elements and locate separate balancing elements in connection with the damping elements.
• FIG. 3 shows a cross sectional view of roll 1 having two damping elements 13 according to the invention.
• Both damping elements 13 have the above-mentioned inner shell 3 and the damping structure 4.
• the damping structure 4 is composed of an intermediate structure 8, which is connected to the inner surface 10 of the shell 10 and/or to the outer sur- face 11 of the inner shell 3 by means of damping components 9 made of vibration-damping material.
• the intermediate structure is used to convert the stresses to shearing forces, which are efficiently damped in the damping components.
• ring-like damping components 9 and an inter- mediate structure 8 are used. Functionally similar parts are referred to using identical reference numbers. Ring-like components are easy to manufacture and install.
• Damping material can be added by using a longitudinal intermediate structure 8, which is shown on the right in Figure 3.
• the damping elements 13 are arranged at a point, which is essentially at a distance of a quarter of the shell 2 length from the shell 2 ends. This positioning provides excellent damping against beam-like vibrations with relatively small damping elements.
• the length of the inner shell 3 is in this case 500-2000, more preferably 1000-1500 mm.
• a similar damping element can also be used in non-rotating structures, such as doctor beams.
• Figure 4a is a sectional view of Figure 3.
• the intermediate structure 8 is composed of one or more profile components 12.
• the profile component 12 comprises at least one part deviating from the radial direc- tion of the roll 1. This construction changes as much as over forces.
• the damping material acts optimally providing good damping.
• thin damping components can be used, which reduces the total mass of the damping arrangement.
• the thickness of the damping co po- nent is 5 - 30%, more preferably 10 - 20%, of the distance between the shell and the inner shell.
• Figure 4b shows a partial enlargement of Figure 4a.
• damping components of two different thicknesses are used.
• the outermost damping components are intended primarily for attaching the profile component 12 to the inner surface 10 of the shell 2. Instead, the innermost damping components are thick for providing sufficient damping.
• the profile component has an inclined section, due to which the stresses caused by the mutual movements of the shells are converted to shearing forces of the damping components. In this embodiment the inclined section forms an angle of 45° in relation to the roll radius.
• the thicknesses of the shell and the inner shell are 90 mm and 5 mm respectively.
• the innermost damping components are 10 mm thick.
• the damping components are preferably elongated sectors, which are attached to the profile component.
• the damping components can be for example quadrangular pieces, which are set at suitable intervals in the longitudinal direction of the profile component. Damping components of other forms can also be used.
• the inner shell can thus be formed of sheet metal material.
• only one profile component is used, which is also made of sheet metal material.
• laser cutting or welding can be used, achieving then dimensional and profile accuracy of both the inner shell and the profile component .
• the thickness of the profile component is 2 mm. Sheet and material thicknesses are dimensioned based on the requirement and the application.
• longitudinal cells are formed in the roll, in which a medium can be conducted for adjusting the roll temperature. On the other hand, the medium can for its part act as a damping material.
• a blank of the inner shell 3 is brought inside the intermediate structure 8, and the blank is stretched at place utilizing the stiffening rings 16 and tensioning screws 15 located at the ribs 16' of the stiffening rings 16.
• the inner shell 3 is also welded to create a continuous form.
• the tensioning screws 15 are used to tension and center the damping structure in place and the whole construction is kept in place by means of the pretensioning force of the tensioning screws. If desired, also glue can be used. This construction allows, for example, circulating water inside the roll. The distance be- tween the stiffening rings is approximately 35% ( ⁇ 10%) of the inner shell diameter.
• the manufacturing method of the inner shell 3 becomes evident from Figure 6, in which the ends of the blank bent to a cylinder are equipped with a finger joint.
• the blank of the inner shell 3 has a cut 18 or a projection 19 at the ends of the periphery, alternating over the seam length. This provides a moderate tolerance for the dimensional accuracy of the blank, when the ends can move in relation to each other unlike in a straight abutment joint.
• the projections 19 can be welded to the cuts 18 at the opposite end providing thus a seam that binds the ends.
• the damping arrangement according to the invention is easy to implement and it can be used in connection with various rolls .
• it is possible to produce a special damping ele- ment, which can be even retrofitted in existing rolls .
• Essential is a formation of movement differences between the structures and the conver- sion of stresses caused by them into shearing forces , which are extinguished in the damping material .
• the roll according to the invention can be used among others as a nip roll , such as a coating roll , calender roll and a king roll of a cutter .
• Nipless applications include for example spreading rolls and extraction rolls of a calender .

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Acoustics & Sound (AREA)
• Aviation & Aerospace Engineering (AREA)
• Rolls And Other Rotary Bodies (AREA)
• Paper (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=27839103

Family Applications (1)

Country Status (5)

Citations (5)

Family Cites Families (7)

• 2003
  • 2003-09-22 FI FI20035161A patent/FI20035161A0/fi not_active Application Discontinuation
• 2004
  • 2004-07-28 AT AT0930204A patent/AT504053B1/de not_active IP Right Cessation
  • 2004-07-28 WO PCT/FI2004/050114 patent/WO2005028884A1/en active Application Filing
  • 2004-07-28 DE DE112004001706.8T patent/DE112004001706B4/de not_active Expired - Fee Related
  • 2004-07-28 JP JP2006526655A patent/JP2007506051A/ja active Pending

Patent Citations (5)

Non-Patent Citations (1)

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