FI82957C - Process for making a roll for a paper machine and a roll made by the method - Google Patents

Description

82957 1 A method of making a roll of a paper machine and a roll made by the method For the production of a roll of paper for a paper machine and for the production of a roll of roll 5

The invention relates to a method for manufacturing a roll of a paper machine and to a roll made by the method.

1Q A method of manufacturing a roll is known in the art, in which a two-part roll structure is formed by placing a guard part formed of rings around a roll core. The rings and the roller core are connected to each other using a shear. The roll produced by the method will comprise a plurality of rings placed side by side. The inner • J5 surfaces of the tires have to be machined, which at the same time leads to a loss of alms. In addition, in said structure, gaps are created between the rings, which have to be welded in order to reach a uniform surface. This still results in harmful welding fluid. Em. the measures increase the overall cost of the roll structure.

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Furthermore, a method of manufacturing a roll is known in the prior art, in which a guard plate is attached to the roll core. In the method, the seams are joined together by welding and the actual shrinkage of the guard plate is performed using overlay welding. The disadvantage of the method is the lack of irregularities which easily remain under the weld or at the joints, which prevent the plate from being pressed tightly into the core during the shrinkage stage, which is a prerequisite for reliable operation of the roll. In addition, in the method, welding is an expensive work step.

The object of the invention is a new type of roll manufacturing method and a roll structure manufactured by the method, in which the above-mentioned disadvantages are avoided.

The object of the invention has been achieved with a solution in which a two-part roll structure is realized so that the plastic deformation area of the jacket material is utilized when the roll shell is mounted on the roll core. When forming the roll structure according to the invention, 2 82957 l of roll roll blank with an outer diameter and a roll jacket blank with an inner diameter are dimensioned so that the diameter difference is 1.5-4 ° / and preferably 2-3 ° / The inner diameter of the roll casing is said to be smaller than the outer diameter of the roll core. The outer roll section is subjected to such a large deformation by heating that sufficient installation clearances are achieved. The heating treatment takes place in such a way that a heating device is placed around or inside the roll shell in an upright position, e.g. utilizing electric resistance, induction or flame heating. The necessary insulation is used on the outside. When sufficient thermal expansion has occurred, the roll core is raised in connection with the upper end of the roll shell and the roll core is lowered into the roll shell. In practice, the required thermal expansion of about 3-5 ° / is achieved with stainless steel, raising the temperature to about 200-300 ° C. The method is particularly advantageous for austenitic stainless steel due to its high coefficient of thermal expansion. Thus, in carrying out such an installation, it is possible to take advantage of the roll core's own weight and high installation speed to ensure a successful installation.

As the roll shell cools, it tends to return to its original shape, the mounting clearances expire, and the inner surface of the roll shell meets the roll core: the outer surface. Since 2-3 was chosen as the crimp, and the thick core is not substantially flexible, the sheath plastlsestl begins; yields when, depending on the material, the wrinkle representing a shrinkage of about 1-2 ° / 00 is exceeded. In this way, the sheath is tightened at each point to the core of the roll-25. In the method according to the invention, the roll shell may be in the sheet metal working state, and the inner surface of the roll shell need not be machined. As a result, significant savings are achieved.

It is also possible to weld the roll shell from the inner surface before shrinking so that no notches or burrs are formed which could remain in the bearing. When manufacturing large rolls, circumferential welds can also be made in the roll shell. In order to control the dimensional accuracy of the blank, it is advantageous not to weld these seams either partially or completely and to complete the welding only after 35 shrinkages. Most preferably, prior to shrinkage, only the root of the circumferential seams is welded, with minimal drawbacks: and finishing of the seam from the inside can be performed. If desired, the parts of the jacket blank can each be shrunk separately using the method according to the invention and the circumferential seams can be welded after shrinkage.

g The method according to the invention for manufacturing a roll of a paper machine is mainly characterized in that the method produces a roll shell blank and a roll core blank so that the inner diameter of the roll blank blank is 1.5-4 ° / smaller than the outer diameter of the roll core blank. then the temperature of the roll shell etaan0 is raised so that the roll core can be placed inside the roll flap, whereby as the roll flap and roll core temperatures equalize as the roll flap shrinks to its original dimension, the plastic flange of the roll flap at least partially tightens and corrects unevenness.

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The central roll of the paper machine according to the invention is mainly characterized in that the two-part roll is formed of a roll-alpha blank with a slit diameter of 1.5-4 ° / QQ smaller than the outer diameter of the roll blank used.

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The invention will now be described with reference to some preferred embodiments of the invention shown in the figures of the accompanying drawings, to which, however, the invention is not intended to be exclusively limited.

Figure 1A shows in principle the method according to the invention in the step in which the roll core is lowered inside the heated roll hub.

Fig. 1B shows a lie in which the temperatures are equalized between the roll hub and the roll hub, and the inner surface of the roll hub is shaped to conform to the shape of the outer surface of the roll hub.

Figures 2A-2E schematically show a method according to the invention for manufacturing a roll of a paper machine, preferably a central roll.

Figure 3 shows Figure 2E in more detail.

Fig. 1A schematically shows a method according to the invention in step 4 82957 1, in which a roll core 12 is placed inside the heated roll shell 11. The inner surface 11a of the roll roll 11 is uncomplicated and thus comprises shape defects which are smoothed by the method according to the invention. The outer diameter of the heat-untreated roll shell 11 is smaller than the outer diameter of the heat-untreated roll core of the same temperature. The diaphragm difference is 1.5-4 ° / 0Q and most preferably 2-3 ° /,

Figure 1B shows the step in which the temperatures of the roll shell 11 and the roll core 12 have stabilized. As the roll shell 11 shrinks towards its initial Ί0 stern dimension, a yield occurs as the inner surface 11a of the roll shell 11 tightens against the outer surface 12a of the roll core 12. The roll shell 11 is tightened at every point and the irregularities of the surface 11a are straightened. The roller shell 11 may have an inner surface in the original plate working space. When the temperatures have finally stabilized between the roll parts 11 and 12, a uniform two-part roll 10 has been achieved, which can be coated, for example, by spraying.

Figures 2A-2E show the method according to the invention step by step diagrammatically.

20: Figure 2A shows a step of the method according to the invention, in which a roll jacket 11 is manufactured, e.g. as sheet work, whereby the inner part of the roller jacket 11 is made. : the surface 11a is uncomplicated and in the plate work space. The diameter of the roll roll formed is measured. Next, a roll core 12 shown in Fig. 25 is formed, which is machined in its outer diameter to the extent that the difference in diameters D 1 -D 2 corresponds to the desired crimp, i.e. in the range of 1.5 to 4 ° / and is preferably in the method according to the invention.

oo J

2-3 ° / oo Figure 2B shows a step of the method according to the invention, in which the jacket cylinder is placed vertically on the floor or the lifting height is a limiting factor in the pit below the floor and in which a heater, e.g. an electric resistance heater (K), is placed around the jacket cylinder.

Figure 2C shows the step in which the desired jacket cylinder temperature is reached and the roll core 12 is lowered by the crane N into the roll jacket 11.

35 5 82957 1 As shown in Fig. 2C, when counting inside the roll shell 11 of the roll core 12, a dozen three by the own weight of the roll is available.

Figure 2D shows the step of the method in which the temperatures of the roll shell and the roll core 5 are stabilizing and the joint is formed.

Figure 2E schematically shows the shrinkage of the roll shell. From point O of the coordinate system, the roll shell begins to shrink toward its original dimension. In the stage, the mounting clearances have expired and the roll shell 10 is tightened in the region under the control of the outer surface of the roll core and partially deformed therefrom. It can be seen from Figure 2E that the shrinkage takes place partly above the climatic limit, whereby the roll shell at least partially yields and the deformations of the roll shell are smoothed out. (Plastic deformation begins above the climatic limit).

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The difference with the prior art is significant because in a normal prior art plate, the anxiety is about 1 ° /. In this case, do not proceed beyond the elastic limit. Therefore, the advantages of the invention are not achieved.

Figure 3 shows Figure 2E in more detail. In the horizontal coordinate system, proceed to the right of the origin so that the 0 point of the coordinate system represents the moment when the maximum thermal expansion is reached and the roll structure begins to cool. The tension of the roll shell can be read from the vertical coordinate. In step O-S 2, as the roll shell cools, the cooled roll shell 11 meets the outer surface of the roll core 12, whereby the tension of the roll shell 11 begins to increase as the roll shell 11 tightens around the roll core 12. As the roll jacket 11 has cooled to room temperature, it has proceeded further to step S £ and the elastic limit has been exceeded. Thus, the shrinkage joint has progressed to the region of plastic deformation, which is essential to smooth out the deformation of the inner surface of the roll shell 30 11.

The following is a preparation example of the production of a roll according to the invention.

35 A paper machine center roll with an outer diameter D of 1600 mm and a length L of 8 m is desired. A guard plate with a thickness S of 12 mm is selected.

Select a shrinkage of 2.5 ° f, ie a diameter difference D - D = Δΐ ,: oo 1 u 1 6 82957 1 A - 2.5 x 1600 mm.

A 1 * —- = 4 mm 1 1000

Select the installation clearance Δΐ „= 3ππη (1.9 ° /). The required thermal difference of 2 oo Δ t to achieve a total deformation of 5, Δ 1 Λ lj + Δ ^ = 7 mm (4.4 ° / oo) 10 is Δ t = 1 = ° / C ° * 260 ° C.

ot _00 17xl0 ~ 6

Stainless steel coefficient of thermal expansion ö (. 17x10 * V ° C 15 between 20-200 ° C.

Work performance:

The sheath is mangled from PL 12 ... 15 plates and a sheath with an inner diameter of 1580 mm is formed. The sls diameter of the finished cylinder is measured and the effective sls diameter is calculated, e.g. 1577 mm. Thus, the diameter of the casting core, i.e. the casting core, should be 1581 mm, whereby Δ1], = 4 mm is achieved.

25 Μ Place the jacket cylinder in a suitable place and lower the heater K - eg around the jacket cylinder of the electric heater. When the desired temperature is reached, the crane 12 is lowered by a crane N into the casing. At this stage, a buffer force of 30-50 t is available, which is obtained from the own weight of the roll core. Thus, the small roundness of the thin plate shank is not detrimental. If necessary, the outlet end of the roll core can be shaped to be guided so that the outlet end does not rub against the inner surface of the plate. Once the temperatures have stabilized, a two-part roll structure 10 formed by the roll core 12 and the roll shell 11 has formed.

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Claims (8)

A method for making a whale (10) in a paper machine, wherein the whale (10) is formed of two parts, a whale sheath (11) and a whale core (12), where the whale shaft (12) is positioned within the roller cell (11), characterized in that, in the process, a make (11) is made for the pickle sheath and a make-up (12) for the pickle shaft, so that the inner diameter (D1) of the make-cutter (11) for the pickle shaft is 1.5 4 e / <»minor In the outer diameter (DJ of the factory cat (12) for the valacaran, the process raises the temperature of the valam sheath (11) after moving about the human loners in the factory catagor so that the valacaran (12) can place inside the valam sheath (11), whereby an Atminatone partial plastic rendering of the roller sheath (11) occurs when the temperatures of the valam sheath (11) and the valakArnan (12) are released and the valam sheath (11) shrinks to an unoriginal dimension, (11) apAnna to and its irregularities straighten out, roll the part (11) Is essentially in the aciw work situation and is formed during shrinkage of one or more parts, which are caused to shrink either together or in succession. 2. A method according to claim 1, characterized in that, in the process, the make of the pickle sheath is designed such that the inner diameter (D,) of the make of the sheave jacket is most advantageously Ar 2-3 ° / OB less and the outer diameter (DJ of the make (12) ) for valakArnan. 3. A method according to claim 1 or 2, characterized in that during the process the roller shaft (12) is applied within the heated roller shaft (11) with a lifting device (N), whereby the roller shaft (11,12) is used in the mutual mounting of the parts. (12) own weight, whereby the valamantelas any eccentricity or other error does not interfere. 4. A method according to any one of the preceding claims, characterized in that during the process the heating element (11) is heated up so that a heating device (K) inside or outside the rolling jacket is advantageously introduced an electric resistor. 10 82957 5. A method according to claim 1, characterized in that in the method the roller sheath (11) is placed vertically in the casting hollow of the casting and that the heating device (K) is lowered by a lifting device 1 from the existing pit in such a way that it will being located on the outer surface of the roller sheath (11) and raising the temperature of the roller sheath by means of the heating device (K) to the desired value, after the roller core is lowered with a lifting device (N) Inside the roller sheath (11). 6. A Vais 1 paper machine made by a method according to any of the preceding claims, which includes a roller core (12) and a roller mill (11) provided with a shrink joint on the outer surface thereof, characterized in that the tapered roller ( 10) is formed by a roll sheath make (11), the inner diameter (D () of which is 1.5-4 Vo »smaller than the outer diameter (Du) of the roll core used (12). 7. A paper machine according to claim 6, characterized in that the outer surface of the roller sheath (11) is coated using thermal spraying. 8. Vais 1 paper machine according to claim 6 or 7, characterized in that the roller sheath is of stainless steel. 25 4 30 in. 35