FI117645B - Heatable roll metal sheath - Google Patents

Description

117645 Heated metal sheath roll

The invention relates mainly to a heated metal watch roll according to claim 1 for use in the manufacture of paper, board or tissue paper.

Particularly in the manufacture of fibrous webs, currently heated rollers, mainly of iron or steel, are used, the inside of which is followed by the circulation of a liquid heat transfer medium either by means of perforations or by a displacement body. When the heating is tracked by a blasting member, there is a chamber 10 in the center of the roll with a blasting member in its center which forces one end of the heat transfer medium introduced into the roll to rotate near the roll shell. In peripheral bore-drilled rolls, fluid transport channels are drilled circumferentially, spaced apart from the shell of the roll. Each channel extends from one end of the roll to the other and back so that the inlet and outlet 15 are on the same side of the end of the roll. There are several disadvantages to the above roll heating methods; as the heat transfer medium passes from the inlet side to the other end of the roll and back to the outlet end in the perforated drilled perforated fluid transfer channels, the heat transfer medium causes the fluid transfer channels to expand, resulting in deformation of the roll casing (so-called pi). The production of periapherical drilled fluid delivery channels is also • · *: expensive. In cast iron or steel sheath v * rolls, however, the heat transfer fluid travels relatively far from the roll * * * and the heat transfer coefficient of the cast iron or steel is relatively low, preventing such a roll from achieving high heat transfer rates. It has also been suggested: * · *: 25 that a heated roll with a displacement member could be better made of a heat-conductive material such as copper, aluminum, tungsten * · * or some steel grades. However, the problem then arises that the heat transfer fluid cools considerably as it travels from one end of the roll to the other, which causes the roll * * to heat unevenly in the CD direction, i.e. the longitudinal direction of the roll; the temperature of the roll shell * * "* 30 at the liquid supply side is higher than at the other end of the roll.

• · • · i ··. ** ·. In order to overcome the above drawbacks, the invention has devised and implemented a novel heating roll which has the following objective: * · **: It is an object of the invention to provide a heating roll prior to all * * * 'manufacturing of a fiber web. 117645 heat transfer fluid would be able to uniformly dissipate heat in the axial direction of the roll. It was an object of the invention to provide a roll whose manufacturing costs would be significantly lower than those of the peripheral drills. It was an object of the invention to provide a thermo roll having a heat transfer coil and thus also a heat transfer power high enough for demanding calendering applications.

The roll of claim 1 achieves the above objectives.

The invention thus relates mainly to a heatable metal-sheathed roll for use in the manufacture of paper, board or tissue paper, the central axis of which has one or more agitators mounted on its central axis and which has a space within the roll which can be partially or completely filled with heat transfer fluid. The metal sheath of the roll is a highly heat-conductive material and at least one agitator is mounted on the center axis of the roll so that when the roll is rotated, the peripheral speed of the mixer is zero or different from the peripheral speed of the roll shell. In a preferred embodiment of the invention, the center of mass of the mixer is eccentric to the bearing position of the mixer 15 in the radial direction of the roll.

The invention is based on the selection of a highly heat-conductive material for the roll material, but instead of a conventional displacement body, one or more stirrers are mounted which are centered on the roll center with its center of mass eccentrically relative to the bearing location in the roll radial direction. Such a construction provides the advantage that, on the one hand, the heat transfer fluid from the heat transfer fluid to the roll shell is good due to the roll material and, on the other hand, the heat transfer fluid allows the heat transfer fluid to be uniformly distributed in the CD direction. With the center of gravity of the mixer outside the bearing position, the mixer does not rotate at all or rotates at a speed that is · · 25 different from the peripheral speed of the roll; on the surface of the jacket.

In a preferred embodiment of the invention, there is a single chamber within the roll, which has one or more plate-shaped mixers mounted on a central axis of the roll.

• · • · • · ·. * ··. In another preferred embodiment of the invention, there is a single chamber within the roll which is filled with a liquid heat transfer fluid or contains a liquid heat transfer fluid and a gas.

• · · • · • · '> • · * 3 117645

Other advantages of the roll according to the invention are as follows: the manufacturing cost of the roll according to the invention is lower than that of peripheral drilled rolls and does not exhibit MD (machine direction) deformation of the roll due to drilling. Nor does the roll according to the invention exhibit a heating profile error in the CD direction (transverse to the machine direction), unlike the prior art roller blades. The heating power of the roll according to the invention is better than that of known rolls without the limitations and disadvantages thereof.

DE-A-4016823 discloses a single-chamber thermo roll with a propeller-like body mounted on a central shaft inside roll 10. If such a body is to achieve effective mixing of the medium within the roll, the propeller must be provided with its own drive, thereby making the roll structure considerably complicated and costly in manufacture. Without its own use, the propeller-like body rotates at the same peripheral speed as the dock, and no effective mixing of the heat transfer fluid occurs.

The roll according to the invention can be used, for example, as a thermo roll for profiling the fibrous web in the calender, for pressing the rolls to remove water from the fibrous web, and for drying the fibrous web after, for example, coating.

In the following, the invention will be described in more detail with reference to the accompanying preliminary drawings. The invention has been described only to the extent • 1 · considered necessary for the understanding of the invention and • · · referring to the general construction of thermo rolls and calendars generally used for calendering and * .2 · fiber web drying refers to prior art. Fig. 1 is a diagrammatic cross-sectional view of a thermo roll having an inside plate of a plate-like mixer according to the invention.

Fig. 2 is a perspective view of a plate-shaped, 3: slightly curved mixer according to the invention.

* ·: 1 · 1 Fig. 3 is a schematic cross-sectional view of a thermo roll having an ϊ., Ϊ säil 30 container which is a mixer whose center of mass is located near the inner surface of the roll shell.

2 ♦ · 1 • 1 3 • 1 • 1 φ 4 1 1 7645., 1

Fig. 4 is a schematic partial sectional view of a portion of a thermal bar having a plurality of mixers according to the invention.

Figure 1 illustrates a mixer according to the invention 1, which is the thermo roll 4 mounted on the central axis 4a as well as the behavior of the mixer, when the roller 5 is rotated at a certain speed, w (angular speed) in the direction of the arrow a closed-end. The thermal roller 4 is per se in a conventional calender with a counter roll, opposite, for example, a polymer coated roll, a shoe roll or a metal roll roll. Between the thermal roll and its counter roll, there is a roll nipple carrying a calenderable fibrous web, such as a cardboard or paper web, which is profiled.

10 The temperature of the fibrous web is increased by the thermal roller, which makes its surface more easily profiled as desired. The aforementioned conventional structures of the calender per se (counter roll, fibrous web) are not shown in the figures.

The (Termo) roll sheath 4b is made of a highly heat-conductive metal such as copper, aluminum, tungsten, special steel. Inside the roll is a chamber 5, 15, which contains heat transfer fluid 2, such as water or oil, supplied at one end of the roll, and a gas 3, such as air. The mixer 1 is mounted on the roll shaft 4a. The Se mixer has a mass m distributed such that the mass of the bearing side of the mixer is m; m2 and, viewed from the bearing, the mass of the outer part is m; ml. The distance of the center of mass of the mixer from the bearing point, i.e. from the central axis 4a of the rolls 20, is r; rl, which is also the radius of the center of mass. Since the center of mass of the mixer 1 is eccentrically located with respect to the bearing point, the gravitational force exerted by the mixer on the downstream side is caused by a gravitational force M = mgrl.

··· • · '···' When the heat transfer medium is to be agitated at P, the angle of the agitator is: *. · The relationship between 25 speed w and the agitation power P = M · w, where M is the torque caused by gravity to the center of mass. . When rotating a piece a = 45 degrees vertically with respect to P, power P = 0.7 · m · r · g · 2 V / D, where the term m »r denotes the mass of the part acting at the distance r from the bearing position eccentric cap., · The mass of 30 pieces is located. This gives m * r = P · D / 0.7 · g · 2V.

on the other hand, when it is desired that a particular mixer has a mixing power P

Due to the gravitational force exerted on it inside the thermal roll, the center of gravity of the mixer 1 must be eccentrically located with respect to its bearing position 4a. In this case · * "; the agitator's own gravity mg, which is imagined to affect the center of mass • 4 · 35 at a certain distance rl from the bearing point, i.e., the center of the thermal roller, causes a certain torque M If the torque M is high enough relative to the heat transfer fluid and the opposite torque caused by the use of the roll, it will prevent the se-5 from rotating with the heat transfer fluid and remain at a certain angle a with the vertical plane P, which vortices effectively mix the heat transfer fluid in the radial and axial direction of the roll 4. The chamber 5 inside the roll may contain only liquid 10 (cf. Figure 4), but It is often more efficient when the chamber contains, in addition to the heat transfer fluid 2, a suitable gas 3 such as air, inert gas, nitrogen, etc. The gas enhances the flows caused by the heat transfer fluid as well as turbulence.

Figure 2 shows another mixer 1 according to the invention. The mixer laa-15 is rotated from a central axis 4 inside the thermal roll; 4a. The mixer 1 shown in the figure is slightly curved and plate-shaped. The agitator has a mass m which is distributed such that the mass of the mixed part at the bearing point is m; m2 and, viewed from the bearing, the mass of the outer part is m; ml. A large part of the mass m of the mixer is located at an end opposite to the bearing point of the body, in the part m; ml. In practice, the mass distribution can be effected, for example, by different materials of the board.

: The center of mass of the body is not located near the bearing, but at a distance r * * · V *; r3 from the bearing position, which causes a certain torque that • · · V · resists rotation of the body with 25 heat transfer fluids such as oil or water in the chamber inside the roll. Heat Transfer Liquid - · * · *: Flows axial (length) and radial currents of the roll which mix • ·. * · *. fluid and improve the uniform distribution of heat in the heat transfer fluid * ·· φ along the length and radial direction of the roll. Due to the fluid flows · ... / in the chamber inside the roll, heat is uniformly transferred to the roll casing, whether at the feed end of the roll '· · 30, i.e. at the end from which the heat transfer fluid is fed to the roll or at the *

· * * * • · ·. ···. Also shown in Fig. 3 is a thermal roller 4 used for calendering, the inside of which is a chamber 5 filled with heat transfer fluid 2. A mixer 1 is mounted inside the roller and is mounted on a central roller shaft 4a. The mixer 1 is shaped to conform to the roll shell 4b and has a mass m almost entirely within the radius 6 117645 r; r2 from the center axis of the roll 4a, whereby the center of gravity radius at the bearing position r; r2 is almost the same as the radius R of chamber 5. In such a mixer 1, the mass causes a high torque M = mgr2 due to gravity, whereby the center of mass of the mixer is positioned almost perpendicular to the vertical plane 5 passing through the center axis of the roll. The agitator 1 scrapes the heat transfer fluid near the inner surface of the roll shell 4b, causing fluid flows in the radial direction of the roll.

Fig. 4 shows a thermal roller 4 provided with a plurality of overlapping plate-shaped stirrers 1 mounted on a central axis of the roll; Γ, 1; Γ ', 1; Γ ".. which 10 correspond to the masses m, m 4, m 5, m 6, and the mass center distances r. R4, r5, r6 roll center shaft 4a vary When the roll is rotated at a certain angular velocity w in the direction of a closed-end direction of the arrow, fitting mixers of the center of gravity of the distance, the total mass and heat transfer fluid angle relative to a vertical plane.

Only certain embodiments of the invention have been described above, and it will be apparent to one skilled in the art that the invention may be practiced in many other ways within the scope of the inventive idea set forth in the claims.

Thus, the mixer may be, for example, in the form of a propeller or may have various spiral-like blades to aid mixing along the length of the roll. In the examples described above, the roll is a thermal roll used in calendering. A particularly preferred thermo roll in accordance with the invention is thermally L, for demanding calendering processes such as calendering the fiber web in longip * * · * quick calendars employing a belt calender or a shoe calender, for example a metal belt calender. However, the roll may also be a used roll in the description of the fibrous web, whereby the fibrous web passes through a roll nip between two rolls.

• · ·:.,. Ί The telanip still has a drainage defect on one or both sides of the fiber web. By heating one or both rolls, the stripping properties of the wire veil: * · *: are improved.

• · »• # *: ** With a plurality of mixers inside the roll in the axial direction, the shape, weight and center of gravity distance of each of the 30 mixers from the bearing point (generally the center axis of the roll) can be individually designed to mix heat transfer fluid. effectively in both the axial and radial directions of the roll. Mixers can be added in series or sequentially. There may also be discontinuities between mixers, 1 * ·· * where there is no mixing.

7 117645

In the examples above, the weight of the agitators is so large that the agitators settle at a certain angle with respect to the vertical when the roll is rotated because they are not sufficient to rotate the pieces on the central axis of the roll. It is to be understood that the angle of the mixer with respect to the vertical plane is not necessarily constant, because, for example, the speed of rotation of the roll and the flows of heat transfer fluid inside the roll chamber influence the position of the mixer.

However, if the mass of the heat transfer medium is large enough and the mass of the mixer and the distance of the center of mass from the axis of rotation are suitably selected, the mixer can also be made to rotate at a rotational speed different from the rotation speed of the roll.

• · • · ♦ • · ·. \ • · • · · · · · · · · · * * * * * · ··· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · anything ·– would all - all - - - · • · • · • · ♦

Claims (11)

117645 1. Upphettbar cylinder (4) med en metal case som används vid tillverkning- 4 en av papper, carton eller mujukpapper, stalk matxel (4a) frnns lagrat copplat ätminstone en blandare (1) and colors det inne i cylindem finns et utrymme (5) ) som kan fyllas delvis eller helt med coloröverföringsvätska (2), nipple tongue 1: av att ··· · · * '* · 20 - cylindems metal sheath (4b) bestär av ett material med hög color conductiv- : tet, • · · * · * · - åminstone en blandare (1) ålår lægår lærlør (4; 4a) lær att blandarens • · Rens mass måttel å belägen excentriskt i förhällande account blandarens lagrings- • · a point of a slund att attand periferihastighet (W) noll eller avviker frän peri-. 25 ferihastigheten hos cylindermanteln dä cylindem roteras runt measuresxeln. • * * * · # * · · A heatable metal sheath roll (4) for use in the manufacture of paper, board or tissue, having at least one stirrer (1) mounted on a central axis (4a) and having a space (5) within the roll which can be filled heat transfer fluid (2) partially or completely characterized in that: - the metal sheath (4b) of the roll is made of a highly heat-conducting material, - at least one mixer (1) is mounted on the center axis of the roll (4; 4a) with respect to the bearing point 10, so eccentric that when the roll is rotated about a central axis, the agitator speed (W) of the mixer is zero or different from the circumferential velocity of the roll casing. 2. Cylinder (4) enligt patent krav 1, kangnetecknad av att blandarens (1) mass-center point for excentriskt i förhällande account-lagringspunkten (4a) i cylin- • * * dems radial and och attar mass mass point * m · · "* Tadkommer et vridmoment M alstrat av blandarens tyngdkrafit, flashes vridmo-: · *: 30 motsätter sig et vridmoment mot blandaren (1) frän cylindems measuresxel *: ·· * (4a). 117645 ίο Roll (4) according to Claim 1, characterized in that the center of mass of the mixer (1) is eccentrically located relative to the bearing point (4a) in the radial direction of the roll and that the mixer center of gravity causes a torque M caused by the agitator 4a) the torque applied to the mixer (1). ' Cylinder (4) enligt face av föregäende patentkrav, colors utrymmet (5) be-stär av en kammare inne i cylindem (1) sträcker sig i närheten av den inre ytan av cylindermanteln (4b). A roll (4) according to any one of the preceding claims, wherein the space (5) consists of a single chamber inside the roll, characterized in that the mixer • (1) extends near the inner surface of the roll casing (4b). Roll (4) according to one of the preceding claims, characterized in that the space (5) has a plurality of mixers (1) which: is mounted bearing-mounted to the center axis of the roll (4a). ♦ * ♦ • · · • · • *. ···. Roller (4) according to one of the preceding claims, characterized in that the mixer (1) comprises turbulence-causing elements in the heat transfer medium. 25 like wings. • · · · ** · »·« 4. Cylinder (4) is a face-to-face patent filing device, a turn-off nozzle (5) finns flera blandare (1), and a frangible copolymer (4a). 5. Cylinder (4) enligt nägot av föregäende patentkrav, kännetecknad av att blandaren (1) innefattar organ, säsom roderblad, mica alstrar turbulens i color-överföringsmediet. 6. Cylinder (4) enligt face av föregäende patentkrav, kännetecknad av att blandaren (1) and utformad för att alstra strömning i cylindems radiala riktning i Värmeöverföringsmediet (2). Roll (4) according to one of the preceding claims, characterized in that the mixer (1) is shaped to cause a radial flow of the roll ***** in the heat transfer medium (2). • · • · - 7. Cylinder (4) enligt face av föregäende patent engraving, colors utrymmet (5) be-stär av en kammare inne i cylindem, som är fylld med flytande coloröverföingsföringsmedium (2) eller som innefattar flytande coloröverföringsmedium (2) och gas ( 3). A roll (4) according to any one of the preceding claims, wherein the space (5), ·. : 30 consists of a single chamber inside the roll filled with liquid * * 117645 heat transfer medium (2) or containing liquid heat transfer medium (2) and gas (3). 8. Cylinder (4) enligt face av föregäende patentkrav, kanknetecknad av att blandarens (1) pulp bel belge of interest cylindems casing * ♦ 1 2 • · 1 * .2 1 20 9. Cylinder (4) enligt face av föregäende patentkrav, kännetecknad av att ♦ 2 · V: in i i utrymmet (5) finns flera blandare, med olika mass (m) och / eller belägna • 1 2 **, „'· Överlappande i förhällande account varandra i cylindems längdriktning och / eller av- ständet (r) frän deras massmittunkt account blandamas lagringspunkt i cylindems: 3: radial area riktning avviker sinsemellan. , ···: Roll (4) according to one of the preceding claims, characterized in that the mixed mass (1) is mainly in the vicinity of the roll shell (4b). Roll (4) according to one of the preceding claims, characterized in that the space (5) has a plurality of mixers having different masses (m) and / or overlapping relative to one another in the longitudinal direction of the roll and / or having a center of mass distance (r) from the point of bearing in the radial direction of the roll. Roll (4) according to one of the preceding claims, characterized in that the roll (4) is used for wet pressing, drying or calendering. 10. Cylinder (4) enligt nägot av föregäende patentkrav, kännetecknad av att cy- • · · lindem (4) används vid vätpressning, torkning eller calendering. • 1 1 · ♦ ·· • · ·. . · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · To ·erate