FI119066B - Calender - Google Patents

Description

119066

Calender

A calender

5 TECHNICAL FIELD

The invention relates to a method according to the preamble of claim 1.

The invention further relates to a calender according to the preamble of claim 2.

BACKGROUND OF THE INVENTION

Calendering generally aims to improve the properties such as smoothness and gloss of a web material such as a paper or board web. In calendering, the web is guided to a nip formed between rolls to be pressed against each other, i.e. a calendering nip, in which the web is deformed by the action of temperature, humidity and nip pressure. In the calender, the nips are formed by a smooth-faced press roll,, · · ·. such as between a metal roll and a roll coated with a flexible coating such as a polymer roll. The elastic roll roll adapts to the web surface shape and presses. **. counterpart of the web evenly against the smooth-faced press roll. In this context • · * ; calender rolls means rollers forming a calendering nip, top roller means the top roll of the roll stack, bottom roll means the lowest roll of the roll stack, and intermediate roll means one or more rolls between the top roll and the bottom roll.

25 Upper nip refers to the highest calender nip formed between the upper roll and the lower roll calender roll, the down nip refers to the roll caliper lower ka-Γ: a calender nip formed between the lower roll and lower roll calender roll, and the spacer nipple refers to the caliper **. calendering nips.

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Fl patent 96334 discloses a method for calendering paper or similar web material in a calender. In the method, the web material to be calendered is passed through nips formed by a deflection compensated upper roll and a deflection compensated lower roll and two or more intermediate rolls arranged between the upper and lower rolls. The rolls are imaged in a substantially vertical roll stack. Intermediate rolls are used rolls which have a substantially similar shape to the natural deflection line caused by its own weight. The nip load caused by the masses of the intermediate rolls and associated auxiliaries is substantially alleviated in the method and an adjustable load 10 is applied to the calendering nips by deflection compensated upper or lower roll and / or external load on the upper or lower roll.

Typically, compression is achieved in a multi-roll calender by securing the top or bottom roll of the roll stack and squeezing the stack of rolls against the fixed roll. Alternatively, both the upper and lower rollers may be pressed toward each other, either such that none of the intermediate rollers are locked in place or at least one of the intermediate rollers is locked in place. The deflections of the rolls can be compensated by deflection compensators on the upper and lower rollers such that the roller nipples have a straight line shape.

*: · * Ί 20 »·· · ... · Lightening of moving intermediate rolls is accomplished in prior art solutions a ·: by so-called UNIX computing. UNIX calculation is based on mechanics where ** • · · * ** rolls and related parts such as bearing housings, struts, and relief cylinders are molded into a moving mass system. This is a very complex computation that requires your own HP workstation and a • ·: ** person who specializes in roller computing.

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SUMMARY OF THE INVENTION

In the solution of the invention, UNIX computing is replaced by automatic weighing; Automatic weighing is achieved by equipping each intermediate roller with a lightweight cylinder 3119066 on both the operating and operating sides with a pQ valve and a linear sensor. Each spacer roller is slowly lifted programmatically from the top spacer roller, starting with the Q instruction of the valve and following the linear sensor reading to its normal operating position. The pressure values are read near the operating position during upward and downward movement 5 and the average of the readings is used as the relief pressure to which any over and under relief is added.

The main features of the method according to the invention are set forth in the characterizing part of claim 1.

10

The main features of the calendar according to the invention are set forth in the characterizing part of claim 2.

Automatic weighing takes into account post-commissioning changes in the masses of the intermediate rolls, which may be due, for example, to the fact that the customer will disable the scraper associated with the intermediate roller over a number of years.

The weight of the pressure sensors can be taken into account in the automatic weighing ···. Minta. In addition to the operating and maintenance side of the mass difference to compensate automatically • · · 20 means, that the solutions according to the prior art has required manual adjustment.

»*: Automatic weighing takes into account the frictions associated with the intermediate roll support systems and automatic weighing can be used to assist in troubleshooting.

··· φ • · * ·· 25 The automatic weighing also takes into account the change in the mass • • .. angle of the mass interleaver. This is not currently taken into account in prior art ** solutions.

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The solution according to the invention can be used in all multi-roll calendars, ··· 30 having at least one intermediate roll. A multi-roll calendar can consist of a single track • · • · 4 119066 or multiple tracks where the rolls form a stack. The roll stack may be vertical or may form an angle with the vertical.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 illustrates a multi-roll calender of two rolls in which the solution of the invention can be used.

Figure 2 shows a second set of rollers and the roller support arrangements associated with the rolls of the multi-roll calender shown in Figure 1.

Fig. 3 is a sectional view of an intermediate roll mounting arrangement.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figure 1 shows a multi-roll calender in which the solution of the invention can be used. The multi-roll calender comprises two rolls 20A, 20B, in which the fiber web W is calendered in the nipples between the roll rolls. First-. * · *. the tracks of its track 20A are indicated from above with reference numerals 21A-25A and · 20 · 20 of the other track 20B with reference numerals 21B-25B. Each track 20A, · ***. 20B upper and lower roller 21A, 25A; 21B, 25B are polymer-coated deflection composites. The upper and lower intermediate rollers 22A, ··· »24A of each of the track 20A, 20B; 22B, 24B are steel rolls, either heated and / or cooled, and middle rolls 23A, 23B are polymer-coated rolls.

25 ·· • Figure 2 shows a second set of rolls 20B and! · Of the multi-roll calender shown in Figure 1. The lower roll 25B of the roller 20B is supported by its bearing ····· on both the operating and maintenance sides of the cylinder device 50 and the upper roller 21B is: * '* · firmly supported on the calender body. The intermediate rollers 22B-24B are supported on the calender body ♦ ** 30 by the pivot arms 32B, 33B, 34B and the pivot arms are moved around the pivot points by the roller cylinder devices 42B, 43B, 44B.

• · 5 119066

Each relief cylinder device 42B, 43B, 44B is provided with a pQ valve A and a linear sensor B connected to the control unit 100. The intermediate rolls are slowly lifted programmatically from the upper intermediate roll 22B, starting with the QQ 5 instruction of pQ valve A and following normal sensor reading. The pressure values are read near the operating position during upward and downward movement and the average of the readings is used as the relief pressure to which any over and under relief is added.

Movable-shell rollers can be used for the upper 21B and lower roll 25B of the roller 20B, whereby the intermediate rolls 22B-24B can be floated between the upper 2IB and the lower roll 25B. The nipples of the track 20B are closed by raising the lower roll 25B with the cylinder device 50 upwards, after which the nipples are loaded with the upper 21B and lower roll 25B diapers.

Fig. 3 is a sectional view of an intermediate roller mounting arrangement. The shaft 22C of the spacer wire 22B is located in the bearing housing 22D which rests on the link arm 32B. The Ni-arm 32B is secured to the body R via a bolt 32C at the pivot point. The relief cylinder is attached to the link arm 32B at position 32D. * * · The cylinder movement is perpendicular to the image plane. The bearings of the link arm 32B to the bolt 32C fixed to the frame R 20 are normally made of bronze bearings, * · · · ... · which are difficult to stiffen for efficient lubrication under all conditions. The tracks of the track are small and movement cycles are intermittent. Due to the lubrication problem, the frictional * * ί ** forces increase, which in turn makes it difficult to control nip forces. A separate lubrication system * · · • · * ··· * also causes additional costs and maintenance. Intermediate Rollers 25 Bronze bushes and lower roller slides can be replaced with self-lubricating normally • ·; '* with graphite-containing bronze material. Also, the wide * * * ··· 'bushings of composite material can act as bearing members. With such an arrangement, frictional conditions are constant and, due to the freedom of maintenance, no separate lubrication lubricants are required.

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In the embodiment shown in the figures, the roll stacks 20A, 20B are substantially vertical, but the roll stacks 20A, 20B may, of course, also form an angle with the vertical for purposes of the invention. The line drawn through the center of the rolls may form a straight line or a broken line.

5

Only some preferred embodiments of the invention have been described above, and it will be apparent to those skilled in the art that they may be subject to numerous modifications within the scope of the appended claims.

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Claims (2)

7 119066 A method for lightening calender spacer rollers, characterized in that the method comprises the steps of: 5. lifting each spacer (22B-24B) from the upper spacer roller (22B) into the QQ of a pQ valve (A) coupled to the spacer roller reduction cylinder (42B-44B). with reference and following the linear sensor (B) reading to the normal operating position of the intermediate roller (22B-24B), - reading the pressure values of the pQ valve during upward and downward movement of the intermediate roller (22B-24B); 22B-24B) as a relief pressure to which any over and under relief is added. Calender with at least one roll stack (20B) having lower (25B) and top roll 15 (2IB) and at least one intermediate roll (22B-24B) with bearing housings supported on the operating and maintenance side of the articulation arm (32B-34B) and which pivot arm (32B-34B) is further supported on a relief cylinder (42B-44B), characterized in that each relief cylinder (42B-44B) is provided with a pQ valve (A) and a linear sensor (B). »·· • · ♦ 1 2 3 · 4 m • • 4 4 4 4 · ·· 1 • ♦ · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · • · 1 · · • 4 4 4 2,444 4 4 * · • · · · · 3 4 4 • 4 4 • 4 8 119066