FI86449B - Procedure and equipment for elimination of barring in a calender - Google Patents

Description

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

The invention relates to a method for eliminating a calendar barring in a calender comprising a lower roll and rollers arranged on the lower roll in the body of the calendar 10 by means of load levers, arranged in a roll stack, the bearing housing of which is supported by means of load levers.

The invention also relates to an apparatus for eliminating a calendar barring in a calender comprising a lower roll and rollers arranged in a roll-15 on a stack of rollers, the bearing housings of which are mounted on load levers supported on the calendar frame.

In multi-roll calendars, barring is a fairly common phenomenon that causes significant problems with the end result of paper calendering. Barring 20 is an itetically induced vibration that occurs as a periodic motion in the vertical direction of the rollers. Self-excitation vibration means that • · in the previous nips, the variation in the thickness of the periodically calendered paper acts as an excitation, causing the calendar to increase its own vibration energy. Barring causes variations in the caliber of the calendered paper, * '* 25 which, when delivered at high speeds, can even be in the order of -' · * + 10%. Changes in the caliber, in turn, significantly weaken e.g.

paper printability.

In the past, attempts have been made to remove the calendar barrlngla with false success with several different solutions. For example, U.S. Patent 3,199,442 discloses a solution in which the bearing housings of calender rolls are supported by fish; support structures through special damping members designed to train the vibration. However, such damping means have not been able to eliminate the vibration of the calender rolls.

• * · «l» f «♦ NSDOCID: <FI 86449B I> 2 86449 1 U.S. Pat. No. 3,111,894, for its part, discloses a solution in which special support rod and pressure roller constructions are arranged, in particular in connection with the upper rollers of the calendar, 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 calendar rolls is to overlap the overlapping rolls of roll roll jQ with respect to each other, i.e., move them relative to each other so that the lime rolls of the roll stack have no common and straight nip. With such an overlap, the distances between the nipples of the roll stack can be changed, and with suitable overlaps, the barring effect has been found to be attenuated. However, the overlapping of the rollers has in the past 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 housings of the bearing housing. This operation has always required the removal of the rollers and has been a very time consuming operation. It has also not been possible to adjust the one-time overlap 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 roll 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 overlapping the roll.

INSDOCID: <FI 86449B I> 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.

20

Fig. 2 is a view corresponding to Fig. 1 of a calendar in which the overlapping of the rolls has been performed in accordance with the invention.

In the figures of the drawing, the calendar is generally indicated by the reference numeral 10. The calendar 10 according to the figures is a four-roll calendar comprising a lower roll 12 and second, third and fourth rolls 13, 14, 15 formed on it as a roll stack supported by load levers 16 on the calendar body 11. Contrary to the figures, the calendar can also be a multi-roll, e.g. a six-roll calendar. 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 commonly used in machine calenders can be replaced, e.g., by cylinders, if the possibility of movement of the lower roll 12 is vertical; direction is deemed necessary. The load levers 16, in turn, are ... e.g., articulated to the calendar body 35 11 in the known manner in the figures by transverse joints 17 of the machine and the peel levers 16 are loaded relative to the calender body 11 by the supports 19 in the body 11. NSDOCID: <FI 86449B I> 4 86449 1 With loading devices arranged between 16.

The load levers 16 can also be lightened, if necessary, by means of lightening 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 calender 10 are not directly and rigidly attached to the load pulses 16, but instead the bearing housings 20 mentioned in the invention are attached to special brackets 21 which are 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 overlap of the rollers 13,14,15 with little adjustment of the adjusting device 23 and to minimize the simultaneous movement of the rollers in height relative to the load lever 16, it is preferred that the joint 22 between the bracket 21 and the load lever 16 be clearly located 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 from this common nip plane A-A; moved 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 aj * ®2 a3 ® from said common nip plane A-A is different.

35 This arrangement ensures that the successive nips Nj »N2 are respectively located in the same vertical plane. When, in such an arrangement, a variation in the thickness of the paper causes a roll NSDOCID at some nipple: <FI 86449B | > 5 86449 1 oscillation, i.e. barrlngia, el this oscillation is amplified in the next nlp because the nipple 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 overlapping the rollers 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 device 18, as illustrated in Figure 2 of the drawing.

15

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 inventive idea defined in the appended claims.

25 /: 30 35 INSDOCID: <FI 86449B I>

Claims (13)

A method for eliminating a calendar barring in a calendar (10), comprising a lower roll (12) and rollers (13, 14, 15) arranged in a roll stack mounted on the lower roll by means of load levers (16) on the calender body 5 (11), the bearing housings (20) of which are supported by means of loading levers (16), wherein, when the rollers (12-15) are in place, at least one roll (13, 14, 15) above the lower roll (12) is moved overlapping the common nip plane (AA) of the roll stack, characterized in that said at least one lower roll ( 12) the upper roll (13.14.15) is moved relative to the load levers (16) of that roll. Method according to Claim 1, characterized in that all the rollers (13, 14, 15) above the lower roll (12) are moved 15 from each other from the common nip plane (A-A) of the roll stack. Method according to claim 2, characterized in that the rollers (13, 14, 15) are overlapped from the common nip plane (AA) so that the displacement (8,, 8,, 3,) of each roll (13, 14, 15) from the common The 20 nip levels (AA) are of different sizes and / or in different directions. Method according to one of the preceding claims, characterized in that the roller (s) (13, 14, 15) are moved by tilting the bearing housings (20) of the roller (s) (13.14.15) relative to the load levers (16). Method according to one of the preceding claims, characterized in that the movement of the roller (s) (13, 14, 15) and the adjustment of the overlap are carried out during operation of the machine. 30 Method according to one of the preceding claims, characterized in that when the overlap is set as desired, the roll (s) (13.14.15) are locked in position. 6 86449 An apparatus for eliminating a calender barring in a calendar (10), comprising a lower roll (12) and rollers (13, 14, 15) arranged as a roll stack on the lower roll, the bearing housings (20) being mounted on the load levers (16) supported on the calendar frame (11) such that at least one of the rollers (13, 14, 15) above the lower roll (12) is movable overlapping the common nip plane (AA) of the roll stack, characterized in that said overlapping roll (13,14,15) the bearing housings (20) are mounted on the load levers (16) mainly movably in the machine direction and are provided with adjusting devices (23) arranged between the bearing housings (20) and the load levers (16), said roll (13, 14,15) the position must be adjusted in relation to its load levers (16). 10 Apparatus according to Claim 7, characterized in that all bearing housings (20) of the rollers (13, 14, 15) above the lower roller (12) are mounted on the respective load levers (16) in a machine-adjustable manner and are provided with adjusting devices (20). 15 Apparatus according to Claim 7 or 8, characterized in that the bearing housings (20) of the rollers (13, 14, 15) above the lower roller (12) are mounted on the load levers (16) pivotally in a cross-machine direction joint (17). 20 Apparatus according to one of Claims 7 to 9, characterized in that the adjusting devices (23) can be rigidly locked in position when the desired overlap of the rollers (13, 14, 15) has been achieved. Apparatus according to one of Claims 7 to 10, characterized in that the adjusting devices (23) consist of elements of variable length. Apparatus according to one of Claims 7 to 11, characterized in that the adjusting devices (23) are hydraulic cylinders or the like. Apparatus according to one of Claims 7 to 11, characterized in that the adjusting devices (23) consist of a screw transmission. ... · 35 NSDOCtD: <FI 86449B I> 8 86449