FI118771B - Roller hole pattern - Google Patents

Description

118771

TECHNICAL FIELD

The invention relates to a roll according to the preamble of claim 1. The invention further relates to a fiber web machine according to the preamble of claim 11. The invention further relates to the use of such devices.

BACKGROUND

Modern fibrous web machines or parts thereof include one or, in most cases, a plurality of rolls which, for example, control said fibrous web. The rolls can also 10 affect the fibrous web in question with a number of different physical properties to alter the physical properties of the fibrous web.

The roller often has channels or ductwork. Usually the channels contain oil. Alternatively, water or steam may be used instead of oil. At present, the number, size, and location of the oil channels (e.g., the distance from the surface of the roll) are determined by the required temperature and stress analyzes. The channels are made in the roll casing “* j, for example by drilling. Typically, drillings are made around the perimeter as often as possible. For example, the angle between the holes is equal, and so on, for example 360 degrees / 27. balancing and temperature range- · · · J ...: heat.

• · · ♦ · ♦. * · *. 20 In current technology, a roller, in some cases a thermal roller, for example, is heated by passing oil through a roller through oil passages near the roll surface. Oil channels. are usually holes in the roll casing. Since the heat is due to oil through the duct wall • · · * ;;; * to the sheath itself and hence to the surface of the roll, the temperature distribution becomes uneven in the circumferential direction of the roll sheath. The surface of the roller at the oil channels is warmer than elsewhere. This, in turn, leads to the so-called. gingerbread pattern on roll surface; •. * · *. the hotter spots are elevated. For example, a 27-channel roll has 27 coil, * 'coils. Thus, there is a 27-fold excitation at the rotation frequency. This example can serve as an excitation for, for example, harmful "barring" oscillation. Further examples of such known solutions are described in the prior art EP 0 710 741 B1 and DE 103 51 515 A1.

118771 2

SUMMARY

The object of the invention is to reduce harmful vibration. According to one aspect of the invention, the object can be achieved by a fiber web machine roll according to claim 1. According to another aspect of the invention, the object may be achieved by a fiber web machine according to Claim 11 having a roll. Moreover, the purpose can be achieved by the use of such devices.

In the invention, the roll of a fiber web machine includes a jacket having channels. The channels are unevenly distributed in the circumferential direction of the fiber web machine roll.

In the numerous embodiments of the invention, the vibration of the roll is reduced. For example, as the rolls 10 rotate, the uneven bump distribution in the roll preferably reduces roll vibration. For example, the harmonic oscillation in the roller due to peripheral drilling of rollers is reduced. With some additional applications, the excitation of barring oscillation decreases with this change. In some further applications, the oscillation that occurs at a frequency equal to the number of bores multiplied by the rotation frequency is decomposed into several (depending on the mathematical "model" of the decay) lower frequency components. That is, instead of one high peak, several low peaks are observed in the spectrum.

• t · · • ·:.: *: In addition, in some additional roller calender related applications (e.g., patented, · * · * tin seeker OptiLoad, conventional super calendars, multi roller machine calendars) Ιοί "]: 20 probabilities of successive nipples in fibrous web, such as paper -:: * · decreases with increasing heredity.

In addition, some further embodiments of the invention are described in the appended dependent claims.

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BRIEF DESCRIPTION OF THE FIGURES

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The invention will be described, by way of example only, with reference to the following: * * *: The following figure, in which: • t · • *: FIG.

DESCRIPTION OF THE ADDITIONAL APPLICATIONS

Referring to Fig. 1, a cross-sectional view of a fiber web machine roll 10 is described here in which the locations of the passages 11 are unevenly distributed in accordance with numerous further embodiments of the invention. In the numerous applications related to Figure 1, it is shown that the bores 11 of the channels 11 are disposed circumferentially so that the channels 11 are not evenly distributed but unevenly distributed in the direction of the circle 12. The distribution of the channels 11 is arranged such that the angle 13 between the channels (i.e., the holes) varies slightly. 5 In Figure 1, the 'gingerbread pattern' of a conventional roll is shown by a blue curve 15. In addition, the positions of the drills of a conventional roll are shown by dashes 16. For the sake of clarity, only two dots are referenced. only two angles 13 and 13 'between the channels 11 for further clarification of the pattern. That is, according to numerous embodiments of the invention, the locations of the bores of the roll 10, i.e. the channels 11, are shown in black dots. In numerous embodiments of the invention, the channels 11 may be oil channels. Other fluids such as water or even steam can also be used in the ducts 11.

However, the change in angle 13 must not be too great so that the temperature distribution does not deviate too much in the direction 12 of the roll 10. If, for example, the spacing of the channels 11 (i.e., the holes depicted in the black dots in Figure 1) varies, for example, in a sinusoidal manner, the portion of the unbalance of the channels 11 curving (i.e., increasing the imbalance) is advantageously eliminated. The sinusoidal cycle is typically •• li * more than 3 cycles per revolution. One of the criteria for maintaining the straightness • · · 20 is the location of the center of the group of channels 11 (i.e., the group of holes) on the back line 14 of the roll 10.

• M • * A good result in terms of vibration excitation is achieved by the completely random placement of channels *: if 11, i.e. holes. In numerous further embodiments of the invention, a suitable simple mathematical method provides a good enough result. In this case, the thermal distortion of the roll 10 must also be guaranteed. In some applications, the effect of vibration due to stiffness variation in the direction of the roll 10 in the direction of the frame 12 is the same as that caused by the deformation of the thermoplastic.

·· •: "In many applications of the invention, the harmonic oscillation of the rollers 10 due to the peripheral bores 11 of the rollers 10 is reduced. In addition, in some cases, the excitation of the barring vibrations occurring • · * · 30 may be minimized. frequency bores x rotation frequency, decomposes into several (depending on the mathematical 'model' of decay) lower frequency components. 118771 4 decreases the caliper fluctuation caused by successive nipples on the paper.

Expression of duct system

Especially in the older machine base, venting the duct system 11, such as the calender moon-5 oil system, after a roll change is a cumbersome and time-consuming operation. The venting is performed almost as a final step and thus directly affects the downtime required for roll replacement. Particularly in the case of thermo rolls, the extraction of air is difficult because the air rises to the top of the roll and is poorly discharged towards the shaft pin 14.

The air can be sucked out of the roll 10 and / or the entire duct system 11, for example the entire oil system, before the fluid is discharged to the roll 10. Compressed air ejector-type vacuum pumps provide a relatively fast 99% air suction. The ejector costs € 1000. This would leave a liter of air in the roller 10 having, for example, a volume of 100 liters of duct system 11. Again, such a small amount of air 15 bubbles easily, does not interfere with the operation of the pumps, and can be vented quickly.

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Sanctions and Scope of the Invention While the foregoing description contains many details, these are only made to illustrate the invention and should not, therefore, limit the scope of the invention. · *; * 20 It is noted that many details can be combined in numerous ways in one or more embodiments of the invention, i.e., it will be apparent to one skilled in the art * ··· * that numerous modifications and variations can be made to the devices without or spirit.

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Claims (11)

1. Vais in a fiber web machine (10), comprising a sheath, which sheath comprises channels, characterized in that the channels (11) are unevenly distributed in the direction of the circumferential circle (12) of the fiber machine roller. Roll according to claim 1, characterized in that the channels are distributed so that the winkein (13,13 ') between the adjacent channels varies. Roll according to claim 2, characterized in that said angle (13,13 ') is defined relative to the midpoint of the rolling circle. 4. A roller according to claim 1, characterized in that the channels are distributed such that the center of gravity of the channels or the center of gravity of liquid which they contain are located substantially on the axis (14) of the roller. Roll according to claim 1, characterized in that the channels are distributed on the circular periphery such that the distance between the channels varies sinusoidally. Roll according to claim 5, characterized in that the variation period for the channel spacing is higher than three per revolution. The roll according to claim 1, characterized in that the channel distribution is random. fair in men's minds. ··· ♦ • j · ' A roller according to claim 1, characterized in that the channel distribution in men is adapted to follow a mathematical model. • e · • · ·. * ··. 20 Roller according to claim 8, characterized in that the duct distribution is adapted to reduce imbalance and heat curl. ··: * ·· 10. Roll according to claim 8, characterized in that the channel distribution is adapted so that the effect on vibration caused by stiffness variation in the periphery of the roll. · 1.1 '25 ring. • · · ♦ · ϊ A fiber web machine having a roller (10), said roller comprising a sheath, comprising::: sheath comprising channels, characterized in that the channels (11) are unevenly distributed in the direction of the circumferential circle (12) on the roller of the fiber machine.