FI98081C - Calendar - Google Patents

Description

98081 5

The present invention relates to a calender for paper finishing according to the preamble of claim 1.

To improve the printability of the paper, it is coated and its surface is smoothed. In particular, the weight properties of coated paper are formed only during calendering. Coated paper grades are most commonly calendered, but the calendering of uncoated printing papers has also become more common because uncoated paper grades are used whenever possible in terms of the quality of the final printed product, as uncoated papers are less expensive than coated papers. Calendering 15 substantially improves the quality of the paper, so it is often advisable to connect calender equipment to existing paper machines.

There are several calendering methods and the best 20 of them are obtained with a supercalender. These machines are used in the production of very high quality coated papers. Other grades of paper are made using various soft calendering equipment, in which the paper is transported between a soft polymer roll and a hard steel roll. It is important for the calendering result that a high pressure and an elevated temperature is applied to the nip, «·. **: so that the paper irones as well as possible. Soft calenders • · ·. ·: Are usually on-machine hardware, but in particular, with older paper webs 30 with a narrower web width, it is conceivable that the yield of the machine will be further improved. by improving the quality of the paper by calendering part of the paper separately * · · · ·. ·; ·. soft calender.

• · · • · ': The problem with the soft calender is the heat resistance of the soft polymer roll, which causes difficulties, especially in the web. in the event of interruptions. If the hot steel roll comes into direct contact with the polymer roll in connection with a track break, it will be immediately damaged. For this reason, current calender devices have very powerful nip force control devices that allow the rollers to be quickly separated from each other after a track break. Because the rolls are very massive, especially on wide paper machines, the calender body is subjected to quite high forces during the separation of the rollers, which is why the body structure of the calenders must be quite massive and firmly attached to the foundations. As a result, the structure becomes expensive, 10 so installing a soft calender on old narrow paper machines is not always profitable. Another problem with current calender structures is the replacement of rollers. The soft roller wears out in use and must be replaced periodically. This results in a long downtime in known calenders, 15 since almost the entire calender has to be dismantled when the roll is replaced. Although replacements due to normal wear and tear can be controlled by adapting them to scheduled maintenance, roller replacements 20 due to unexpected roll damage 20, such as due to line breaks, stop on-machine production of the entire paper machine for a long time.

It is an object of the present invention to provide a calender structure in which the compressive force of the rolls is not derived from the calender / | 25 frame through the foundations and where the rollers can be changed • ·. *. * Quickly.

The invention is based on the fact that the end bearings of the calender are fastened to each other by means of joints and the rollers are pressed t · · 30 together by actuators on the opposite side of the joint. · · · · · · · · · · · · · · · · · · · ·

More precisely, the calender according to the invention is characterized by what is stated in the characterizing part of claim 1: V 35.

3,98081

The invention provides considerable advantages.

The calender according to the present invention is lightweight and inexpensive to manufacture, so that it can be adapted to existing paper machines at low cost. This device is particularly well suited for small paper machines, allowing the life of the machine to be increased by improving the quality of the paper, even if the machine might otherwise have to be replaced too small and inefficient. The track of the entire calender 10 can be changed in one package and the track change is very fast. Production interruptions thus remain short, as a second track can be kept in reserve, which is quickly raised in place of the worn track. The nip force of the calender is generated by actuators acting on its end bearings, so no heavy frame structure is required, no nip and release force need to be applied to the calender body and foundations. The space requirement of the calender is small and the track is well visible, so the operating personnel can easily service the device. Since heavy frame-20 structures are not required, the installation of the calender is very fast and its manufacture is inexpensive.

The invention is explained in more detail below in the accompanying drawings. with the help of

Fig. 1 shows one embodiment of the invention.

• · • ·· m ··· • · · '* Figure 2 shows another embodiment of the invention.

Figure 3 shows a third embodiment of the invention.

• · · * · · • · · •:. As can be seen from the figures, the calender according to the invention can be placed on simple frame brackets 1. The actual calender body is formed by the end bearing brackets 2, 3, or 11, 12 or 13, 14, 15 of the rollers 8, 9: V 35, on the bearings of which the rollers rotate. In the solution 4 98081 of Fig. 1, the soft roll 9 is placed at the bottom and its end bearing bracket 11 has lugs 4 on which the entire calender rests on the frame brackets 1. The steel rack 8, i.e. the hard r roll bearing bracket 12 is connected by a hinge or joint 5 to the soft roll 9 bearing bracket 11. On the opposite side 8, 9 there is a hydraulic cylinder 5, the cylinder of which is attached by a joint 6 to the bearing bracket 1 of the soft roll 8 and whose piston rod is attached by a second joint 7 to the bearing bracket 12 of the hard roller 8. The natural-10 stitch frame has a similar structure.

The required nip force is obtained by pressing the bearing brackets 11, 12 and the rollers 8, 9 attached to them by a cylinder 5 around the joint 10.

The track of Figure 2 is quite similar to the track of Figure 1, but with the soft roller 9 placed at the top. Also in this solution, the track rests on the lugs 4 of the bearing bracket 3 of the soft roller 9 and the hard roller 8 hangs with its bearing brackets 2 below it. The invention thus provides an apparatus with which the paper can be calendered on both sides simply by positioning; similar tracks in a different position.

If the calendering result is to be improved, the paper must be passed through several nips. In the solution of Fig. 3, the soft roll 9 is placed between two hard rolls 8 and the bearing brackets 13, 14, 15 of the rolls 8, 9 are connected in a manner according to the invention by joints 10 and hydraulic cylinders. lä 5. The bearing bracket 14 of the middle soft roller 9 is «· ♦, · ♦ 30 profitable and the track rests on its lugs 4. Here: In the T: track, the paper passes through two nips.

In addition to the above, the present invention has other embodiments.

i’V 35:: The track can also be adapted to the lugs attached to the hard roller bearing bracket 5 98081 and there can be several rollers as required. It is also conceivable for the rollers to be placed in a position other than vertical overlap.

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Claims (6)

98081 A soft calender comprising a frame structure (1) and at least one soft roll (9) and at least one hard roll 5 (8) and bearing brackets (2, 3) with bearings to which the rollers (8, 9 are rotatably attached at their ends, characterized by - a hinge (10) with which the bearing brackets (2, 3) of the same roller end are pivotally connected to each other, and 10 - at least one actuator (5) at each end of the rollers, with which the rollers (8, 9) can be pressed by means of bearing brackets (2, 3) by turning them around the hinge (10) Calender according to Claim 1, characterized in that the actuator (5) is on the side of the rollers (8, 9) opposite to the hinge (10). 1 Calender according to Claim 1 or 2, characterized in that the bearing bracket (3) of the soft roll (9) has lugs (4) on which the rollers (8, 9) are arranged. A calender according to claim 3, characterized by; 25 characterized in that the bearing bracket (12) of the hard roller (8) is • • ** fitted on the bearing bracket (11) of the soft roller (9). Calender according to Claim 3, characterized in that the bearing bracket (2) of the hard roll (8) is arranged below the bearing bracket (2) of the soft roll (9). . i · · • · · '· · *. Fish blade according to one of the preceding claims, characterized in that a first hard roll (8) and a soft roll (9) are arranged under the soft roll (9). : A second hard roller (8) is fitted on top of the 35. 98081