FI86449C - OVER APPARATUS FOR OIL ELIMINERING AV BARRING I EN KALANDER. - Google Patents

Description

86449 1 Method and apparatus for eliminating the calendar barring Förfarande och apparatur för eliminering av barring i en kalander 5

The invention relates to a method for eliminating a calendar barring in a calendar, which comprises a lower roll and rollers arranged on the lower roll on the frame JO by means of load levers, arranged in a roll stack, the bearing housings of which are supported by means of load levers.

The invention also relates to an apparatus for eliminating a calendar barring in a calendar, comprising a lower roll and rollers arranged on a stack of rollers on a lower roll, the bearing housings of which are mounted on load levers supported on the calendar frame.

In multi-roll calenders, barring is a fairly common phenomenon that causes significant problems with the end result of paper calendering. Barring 20 is a self-excited oscillation that occurs as a periodic motion in the vertical direction of the rollers. Self-excited vibration means that the thickness of the paper periodically calendered in the previous nips- * ’! the variation acts as an excitation, whereby the calender itself increases its vibration energy. Barring causes variations in the caliber of the paper to be calendered, '25 which can be on the order of ··' + 10% when delivered at high speeds. Changes in the caliber, in turn, significantly weaken e.g.

paper printability.

Attempts have been made in the past to remove the calendar barring with varying degrees of success. For example, U.S. Patent 3,199,442 discloses a solution in which the bearing housings of calender rolls are supported by fish; to the supporting structures of the vehicle by means of special damping means intended to dampen vibrations. However, such damping means have not succeeded in eliminating the vibration of the calender rolls 35.

* · * · • · 2 86449 1 U.S. Pat. No. 3,111,894, on the other hand, discloses a solution in which, in particular in connection with the upper rollers of the calender, special support rod and pressure roller constructions are arranged in order to eliminate vibration. This system, too, has not been found to work perfectly.

The most effective way to remove or reduce the calender barring in a multi-roll calendar comprising a roll stack of multiple overlapping calender rolls is to overlap the overlapping rolls of the roll stack 10 relative to each other, i.e., move relative to each other so that not all rolls have a common and straight nip. With such an overlap, the distances between the nips of the roll stack can be changed, and with suitable overlaps, the barring effect has been found to attenuate. However, the overlapping of the rollers has previously been very difficult to perform, since in practice the overlapping has been done by inserting spacers of different thicknesses between the bearing housings of the rollers and the load levers of the bearing housings. This operation has always required the removal of the rollers and has been a very time consuming operation. Also, once the overlap has been performed, it has not been possible to adjust it other than by removing the rollers and changing the thickness of said spacers.

It is an object of the present invention to provide a method and apparatus which provides a significant improvement over prior art solutions. To achieve this, the method according to the invention is mainly characterized in that when the rollers are mounted in place, at least one roll above the lower roll is moved relative to its load levers so that said roll overlaps from the common nip plane of the roll stack.

30

The apparatus according to the invention is mainly characterized in that the bearing housings of at least one of the rollers above the lower rollers are mounted on the load levers mainly in the machine direction and provided with adjusting devices arranged between the bearing housings and the load levers, the position of said roll being overlapping.

3 86449

The invention achieves several significant advantages over the previously known solutions, and in connection with these advantages, e.g. following. In the invention, the barring effect of the calendar is eliminated by arranging the rollers with respect to each other, and this overlap can be performed according to the invention without removing the rollers. Thus, the overlapping of the rolls according to the invention is a much simpler and faster operation than before. According to the invention, the overlapping of the rollers can be performed either while the machine is standing or running. The overlap adjustment can also be easily performed and, if necessary, it can be done with 10 machines running. The overlap control can also be automated in the invention, because the overlap control devices can be easily connected to e.g. computer control. Other advantages and features of the invention will become apparent from the following detailed description of the invention.

The invention will now be described in detail with reference to the figures of the accompanying drawing.

Figure 1 shows a fully schematic side view of a calendar in which the method and apparatus according to the invention have been applied.

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Fig. 2 is a view corresponding to Fig. 1 of a calender in which the overlapping of the rolls has been performed according to the invention.

In the figures of the drawing, the calendar is generally indicated by the reference number 10. The calender 10 according to the figures is a four-roll calender comprising:. a lower roll 12 and a second, third and fourth roll 13, 14, 15 formed on it as a roll stack, which are supported on the calender body 11 by means of load levers 16. The calender can also be a multi-roll, e.g. a six-roll calender, contrary to the figures. The lower roller 12 is supported on the base B 30 from the lower roller bearing housings 24 by means of fixed supports 25. However, the fixed supports 25, which are commonly used in machine calenders, can be replaced, for example, by cylinders, if the possibility of movement of the lower roll 12 is vertical. : direction is deemed necessary. The load levers 16, on the other hand, are articulated to the calender body 35 11 by means of transverse joints 17 of the machine, and the load levers 16 are, for example, in the known manner shown in the figures. : with respect to the body 11 of the calender by means of loading devices 18 arranged between the supports 19 4 86449 1 in the body 11 and the load levers 16.

The load levers 16 can also be lightened, if necessary, by means of relief devices or beams marked with reference numeral 18 '.

In the solution according to the invention, the bearing housings 20 of the second, third and fourth rolls 13, 14, 15 of the calendar 10 are not directly and rigidly attached to the load levers 16, but instead the bearing housings 20 mentioned in the invention are attached to special brackets 21 articulated and pivoted. In addition, control devices 23 are arranged between the brackets 21 and the load levers 16, by means of which the brackets 21 and the bearing housings 20 can be pivoted about the joint 22 relative to the load lever 16. While the bearing housings 20 are rotated by the adjusting devices 23 around the joints 22, said bearing housings 20 15 and thus also the rollers move from their previous nip plane. The rollers 13,14,15 thus overlap with respect to each other. In order to maximize the overlapping movement of the rollers 13,14,15 with little adjustment of the adjusting device 23 and to minimize the simultaneous height movement of the rollers relative to the load lever 16, it is preferred that the joint 22 between the bracket 21 and the load lever 16 aside. A preferred embodiment can therefore be considered to be the solution shown in the figures, in which said joint 22 is located just at the upper edge of the bracket 21. Correspondingly, the figures show that the adjusting device 25 23 is arranged at the lower edge of the bracket 21, whereby the power requirement of the adjusting device 23 is as small as possible.

Fig. 2 shows a situation in which the rollers 13, 14, 15 have been moved overlapping with respect to each other by utilizing the control devices 23. The nips 30 between the rollers and then are not located in the common nip plane A-A corresponding to Fig. 1, but are shifted from this common nip plane A-A to the side. According to Fig. 2, the overlap from the common nip plane A-A on each roll is further different, so that the displacement of each roll 3j * a2 and a3 from said common nip plane A-A is different.

35 This arrangement ensures that the successive nips ^ a, respectively, are not located in the same vertical plane. In such an arrangement, when the variation in the thickness of the paper in one nip causes the roll 5 86449 1 to vibrate, i.e. barring, this vibration is not amplified in the next nip because the nip levels are in different directions.

The figures in the drawing show a hydraulic cylinder 5 used as a control device 23. Such a solution is advantageous especially if the control is to be automated. However, the adjusting device 23 according to the figures can be replaced by, for example, a screw or the like, if automatic adjustment is not necessarily necessary. However, the adjustment length of the adjusting device should most preferably be more than 40 mm in order to make the possibility of overlap of the rolls telq sufficiently large, i.e. 20-30 mm. As already stated above, when the rollers overlap, the position of the rollers in the height direction also changes. However, the change in height can be taken into account and corrected by means of the loading devices 18, as illustrated in Figure 2 of the drawing.

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The invention has been described above by way of example with reference to the figures of the accompanying drawing. However, the invention is not limited to the example shown in the figures, but many modifications are possible within the scope of the invention as defined in the appended claims.

. 25 /; 30 35

Claims (13)

A method of eliminating calender bearings in a calender (10) comprising a lower roll (12) and rollers (13,14,15) arranged in a roll stack and mounted on top of the lower roll of the body (11) by the calender by means of load levers (16), the bearing housings (20) of the rollers (13,14,15) being supported by the load levers (16), where the rollers (12-15) are mounted in place, at least one roll ( 13,14,15) which is above the lower roll (12) in an overlapping manner from the common key plane (AA) of the roll stack, characterized in that said at least one roll (13,14,15) which is above the lower roll (12) is moved relative to the loading levers (16) of the roll. 15 Method according to claim 1, characterized in that all the rolls (13,14,15) located above the lower roll (12) are transferred in an overlapping manner from the common key plane (A-A) of the roll stack. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Method according to claim 2, characterized in that the 2 rolls (13,14,15) are transmitted in an overlapping manner from the common 3 same key plane (AA) in such a way that the displacement (β, β, β}) of 4 each roll (13,14,15) from the common key plane (AA) is of 5 different sizes and / or different directions. 6 7 4. A method according to any of the preceding claims, characterized in - 8, that the roller (s) (13,14,15) is transferred by leaning on the bearing housings (20) of the roller (s) (13,14,15) in relation 10 to the load levers (16). 11 12 5. A method according to any of the preceding claims, characterized in that the transfer of the roll (s) (13,14,15) 14 and the adjustment of the overlap are carried out while the machine is in the thread. 16 6. A method according to any of the preceding claims, characterized in that, where the overlap is regulated in the desired manner, the roll (s) (13,14,15) is read in its position. An apparatus for eliminating calender bearings in a calender (10) comprising a lower roll (12) and rolls (13,14,15) arranged in a roll stack on top of the lower roll, wherein the bearing housings (20) of the rollers ( 13.14.15) are mounted on load levers (16) which are impacted against the body of the calender (11) in such a way that each of the rollers (13.14.15) above the lower roller (12) is displaceable in overlapping ways from the common key plane (AA) of the roller stack, characterized in that the bearing housings (20) of said overlapping roller (13,14,15) are mounted on the load levers (16) mainly for being displaced in the machine direction and provided with control devices (23) arranged between the bearing housings (20) and the load levers (16), with which the position of said roller (13,14,15) can be controlled in relation to their load levers (16). Installation according to claim 7, characterized in that the bearing housings (20) of the rollers (13,14,15) above the lower roll (12) are mounted at corresponding load beams (16) in the machine direction in an adjustable manner and provided with control devices. (20). Installation according to claim 7 or 8, characterized in that the bearing housings (20) of the rollers (13,14,15) above the lower roll (12) are mounted in a pivotal manner at the load beams (16) with a hinge (17). ) which is transverse in relation to the machine. Installation according to any of claims 7-9, characterized in that the control devices (23) can be read rigidly at their position where the desired overlap of the rollers (13, 14, 15) is achieved. Installation according to any of claims 7-10, characterized in that the control devices (23) consist of means of variable length. 35 12. An installation according to any of claims 7-11, characterized in that the control devices (23) consist of hydraulic cylinders or the like. Installation according to any of claims 7-11, characterized in that the control devices (23) consist of a screw connection.