FI113071B - Calender - Google Patents

Description

1, 113071

Calendar

The invention relates to a calender of the type shown in the preamble of claim 1.

5

In multi-nip calendars, the paper web is calendered by overlapping the nipples between the calender rolls arranged as a roll stack. The rolls are mounted on a calendar body and are arranged in nip contact with one another so that the paper web can be calendered 10 by passing it through the nipples and applying a certain load between the rolls to provide a line load on the nip. For example, Finnish Patent 95062, corresponding to US Patent 5,590,593, discloses a calender in which in a stack of four rolls the two lower rolls are bend-compensated, preferably zone-adjustable rolls and have fixed mounting, i.e. their bearing housings are rigidly mounted on the calender base. The two upper rollers, the uppermost of which is also a deflection compensated roller, preferably a zone-adjustable roller, are mounted movable with their bearing housings secured to the calender body pivotable load arms. The top, or-20, pump-compensated roll may be provided with a flexible coating, and the second top roll must be heated so-called. a thermo roll. Also, the lowest, deflection compensated roll in the calender roll stack may be provided with a flexible coating. The calendar has alternative modes of driving, such as fish ·. passing a paper web to be sharpened through all three nipples closed or opening the top nipples through only two or one nip respectively. Advantages include: the fact that the calendar achieves substantially all the same benefits that can be achieved with conventional soft * calendars, in addition to which the middle nip in the calender is a hard nip that can equalize caliber. In addition, the calender's flexibility makes it 30 suitable for many paper grades.

Corresponding convertible calendars are also disclosed in European Application Publication 890676 and GB Application Publication 2119422. European Application Publication 890676 discloses a calender with 35 rolls attached to a calender roll stack. The top roll is fixedly fixed to the frame, the middle rolls are fixed to the load arms, and the lowest roll is arranged in a carriage that is vertically displaceable in the guide. The top and bottom rolls are deflection compensated rolls and the 2 113071 top and bottom rolls and the two middle rolls are elastic coated rolls, while the second lowest and second top roll are hard surface rolls. Typically for the calendar, when the top and bottom nip are closed, the other intermediate nips are open, whereupon the web 5 can be calendered symmetrically with the top and bottom nip and passed through the open nipples and through the output rollers adjacent to the rolls forming the open nip.

GB application 2119422, on the other hand, relates to an arrangement 10 in which two stacks of three rolls are disposed side by side in the same calender frame, each of the middle rolls being a hard roll and fixed on both sides with soft thence. These rolls above and below the hard roll 15 in each stack are adjustable for deflection. One of the soft-surface rolls of each roll stack serves only as a spare roll, which can be activated when the actual nip contact soft surface roll is damaged, for example, and thus the calender effectively functions as a double-nip calender 20 formed by two pairs of rolls.

U.S. Patent 4,332,191, Figs. 5D and 5E, shows a calender having two stacked three rolls, one of which in the upper middle is a soft roll and in the lower all rolls are hard rolls. In addition: 25 calendars have a stack of three rollers on the other side of the frame, with the middle roller soft. The web can be calendered by exporting it. '· /. through stacks with a soft center roll, or lowering: the lower roll of the upper stack to the lower stack yields four hard, · *; a stack of rolls through which the three nipples pass the web.

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Also known as the OPTIGLOSS ™ soft calender, which has two separate three-roller rolls, each with a middle roll which is a hard thermal roller and has a soft-surface roll on each side. This gives a total of 6 rolls of 4-nip calendars.

35

As described above, all calender structures are characterized by opening the nipples by means of the loading arms or by moving other calender roll supporting supports, such as a roll carrying carriage in the roll guides. This has been a prerequisite for opening the nipples when changing the calendering mode, i.e., changing the number or position of the calendering nips, e.g., by changing the quality of the paper being produced. Similarly, prior art solutions, such as EP-890676, are characterized in that the calendering mode is changed by opening some of the nipples and inserting the web through the remaining closed nipples. This results in many rollers having to be moved.

It is an object of the invention to provide a calender which can be modified in a new simple manner. To accomplish this purpose, the calender according to the invention is essentially characterized in what is set forth in the characterizing part of the appended claim 1.

The calender has two stacked three rolls stacked, the rolls 15 being movable so as to provide one run nip between the middle rolls or two run nips to each stack.

Stacks of three rolls superposed on the same calender body of the calender each preferably have a thermal roll in the middle and a soft surface roll at the top and below. The soft-surface rolls are preferably movable-shell rolls, whereby they can be moved in the nip plane direction by radially moving the diapers. The mobile diaper rolls are fixedly fixed to the calender body. In this case, the lower movable jacket roll of the upper roll stack and the upper 25 movable jacket roll of the lower roll stack are movable by moving the diapers: • to and from the nip contact with the upper roll and the middle roll of the lower roll stack. The upper roll of the upper roll stack and the lower roll of the lower roll stack are likewise movable by means of the movement of the roll mantle in the direction of the nip plane. ···. 30 from the last roll and back into the nip contact with the middle roll. The rollers are fixedly fixed to the frame at such distances from each other that the movement of the movable roller rollers allows all nipples to be opened.

The invention makes it possible to convert the calender only by arranging the middle rolls (the top roll of the lower roll stack and the lower roll of the upper roll stack) into and out of each other by arranging its own stack centered. For example, it is possible to perform a · · „113071 symmetric calendering in four nip formed by a hard surface roll and a soft pin roll with the lower calender roll of the upper stack and the upper calender roll of the lower stack open, or mat calendering by lowering the closed nip between rollers. Suitably, the distance between the axes of the rolls, the diameters of the roller shells, and the radial movement lengths of the roller shells can be dimensioned only by displacing the roller shrouds, i.e., no separate roller transporting devices are required.

10

The invention will now be described in more detail with reference to the accompanying drawings, in which Fig. 1 is a side view of a calender with nipples open, Fig. 2 shows a calender in a first run, and Fig. 3 shows a calender in a second run.

Figure 1 shows a side view of the calender. In the calender body R are superimposed six rolls forming two triple roll piles A and B. In the upper roll stack A, the top and bottom rolls 1 and 3 are movable diaphragms whose diapers are displaceable radially through the nip plane passing through the axes of rotation of the rolls. The roll covers of the rolls 1 and 3 in question are of a soft surface, for example, with a polymer coating. Between the highest and lowest rolls 1, 3 there is a hard heated roll 2, i.e. a so-called roller. a thermo roll. The surface of this middle roll 2 may be, for example, a smooth metal surface.

: »· <· 30 The lower roll stack B having roll nip plane extending to the upper roll stack <· t non A has similar rolls and in the same order as the upper roll stack A, i.e., the middle hard heated thermo roll 5 and above a soft-surface movable ·; 'sheath roll 4 and 6 respectively.

: / - i 35

Rolling shells 1, 3, 4 and 6 are so-called. SYM rollers with a fixed shaft for applying power to the various zones of machine width • »*. *. radially applied loading means by means of which the roll casing can be moved • · 5 113071 in a radial direction, in particular in a nip plane direction, for opening and closing the roll nip and adjusting the roll load.

5 The movable diaper rolls 1, 3 and 4, 6 of both rollers A, B have all the same dimensions and construction and the middle rolls 2 and 5 of each roll stack A, B have the same dimensions, so that only two types of rolls are needed for spare parts .

10

The movable-sheathed rollers 1, 3, 4 and 6 are secured to the roll body R by means of substantially stationary brackets 9 which support a fixed axis of the roll at both ends. Although Figure 1 shows the horizontal bolts 8 for securing the brackets 9 to the calender frame R, other means of securing the brackets to the stationary frame can also be used. The center rolls 2 and 5 of roll stacks A, B can be secured from their bearing housing to the frame R via pivoting supports and lightened hydraulically at each end by a hydraulic cylinder acting on the bearing housing and body 20 according to known articulation principles.

The rolls are disposed on two overlapping piles A, B such that movable-sheath rolls 1, 3, 4 and 6 can be moved away from the middle hard rolls 2 and 5 and the lower roll 3 of the upper roll stack and the upper 25 rolls 4 of the lower roll stack. N1, N2, N3, N4, N5 Up-: * · The wedding down is open. Figure 1 illustrates this situation. The distance d of the roll diapers I in the nipples may be a few millimeters, e.g. less than 10 mm.

: ··. Figure 2 shows the first driving situation where each roller, ··. 30 non A, B both nips N1, N2 and N4, N5 are closed, i.e. a calendering nip is formed on either side of the heated thermal roller 2, 5 with the corresponding soft-surface roll 1, 3 and 4, 6. Thus, in the first running situation, the web to be calendered is passed through a total of four nips, all of which are nip formed by a soft-surface roll and a hard heated roll. Between the roll stacks, the web goes through the open nip N3. The web must also be calendered symmetrically, i.e. in the first roll stack the first surface is hard against the hot roll roll · 'and in the next stack the opposite surface is against the hot hot roll 6113071 roll. By adjusting the load and / or temperature, different sides can also be treated differently in successive roll stacks A, B.

Fig. 3 shows another driving situation in which the lower roll 5 of the upper roll stack A and the upper roll 4 of the lower roll stack B are displaced from the middle roll 2 and 5 of the respective roll stack, i.e. they are displaced in the nip plane to close the space between the rolls. a calendering nip N3 is formed, which is bounded on each side by a soft-surface roll. The calenderable web is run in this driving mode 10 only through this nip N3 to perform mat calendering. In this driving mode, the rolls 3 and 4, the SYM rolls, are rotated 180 ° so that the loading members are aligned with the calender nip N3. If either or both rollers are provided with two sets of loading members 180 ° apart within the roll shell, the roll need not be turned.

15

The nip N3 may also be formed by lowering the lower roll B 6 of the lower stack B and the central roll 5 attached to the frame via the pivoting supports, thereby releasing the nip N4, and lowering the lower roll 3 of the upper stack A to form the nip N3.

20

There is no need for separate loading cylinders in the calender since the loading can be achieved by the loading members inside the SYM rollers (soft-surface rollers 1, 3, 4, 6).

In addition, the drawings show the calender take-out rollers 7, which:: allow the calenderable web W to be taken out of the nipples and are located V on both sides of the roll stack A, B.

I *: Preferably, the above calendar performs on-line calendering of paper, whereby it can be placed in a papermaking line. The Kalan blade is short in the machine direction, making it easy to place it in an old line, for example during rebuilds. In addition, the change of species, that is, the change of the driving mode ::: from the calendering mode of Figure 2 to the calendering mode of Figure 3, and the conversion is easy.

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Claims (5)

1. Calendars having two stacks (A, B) of three rollers arranged one above the other, that between the stacks there is a space bounded by the bottom roll (3) of the upper stack (A) and the top roll (4) in the lower stack, characterized in that said two rolls (3, 4) are soft surface rolls, and they can each be separated from the nip contact with the rolls (2, 5) by their own roll stack and carried to the nip contact (N3 ) together. 10 Calender according to claim 1, characterized in that the upper roller (1) of the upper roller stack (A) and the lower roller (6) of the lower roller stack (B) are also soft surface rollers, and the middle rollers ( 2, 5) in the roll stacks (A, B) are hardened rolls. 15 Calender according to claim 2, characterized in that the center rolls (2, 5) are heatable thermo rolls. 4. Calender according to any of the preceding claims, characterized in that at least the lower roll (3) in the upper roll stack (A) and the top roll (4) in the lower roll stack (B) are installed fixedly on the calender. body (7) said that their mantles can '; is moved in the direction of the roller stack relative to the support of the rollers (9). t · * · Calender according to claim 4, characterized in that at least ': the lower roll (3) in the upper roll stack (A) and the top roll (4) in the lower roll stack (B) are provided with load means inside the roll sheath. ; 30 * · »