EP0571582B1 - Roll press - Google Patents

Abstract

PCT No. PCT/DE92/01030 Sec. 371 Date Aug. 9, 1993 Sec. 102(e) Date Aug. 9, 1993 PCT Filed Dec. 10, 1992 PCT Pub. No. WO93/12290 PCT Pub. Date Jun. 24, 1993.A press includes at least two press units supported by respective bearing brackets. The bearing brackets are coupled together by releasable tension rods which transmit a pressing force. When the two press units are not transmitting a pressing force in a pressing plane, the tension rods are prestressed at a maximum of a fraction of the maximum pressing force. One of the bearing brackets is movable relative to the other bearing bracket along the pressing plane. The bearing brackets are guided by a pair of guide surfaces disposed parallel to the press plane.

Description

The invention relates to a roller press, preferably for treating a running web, e.g. Paper web. The roller press comprises two press units, e.g. Press rolls, the main axes of which lie in a press plane and which together form a press nip through which the web runs. The roller press can also comprise three press units, which form two press nips, or four press units, which form three press nips.

The invention relates to a roller press with the features specified in the preamble of claim 1. For the prior art, reference is made to US 3,921,514. In this construction, the internally generated (between zero and a maximum) pressing force is transmitted directly from the bearing blocks of one roller to the bearing blocks of the other roller with the aid of tension rods which are designed as screws. The machine frames belonging to the roller press therefore only need to be dimensioned for the weight of the rollers, but not for the transmission of the pressing force.

The invention relates in particular to the construction in which one of the two roller shells can be pressed onto the other roller by means of an internal pressing device (for example a press shoe) and can be removed again from the latter. A recurring problem arises when, for example, an endless felt belt running through the press nip has to be replaced in a roller press. In the case of a shoe press unit, the flexible press jacket also has to be replaced from time to time. In the cases mentioned, a gap must be temporarily created at least on one of the two roller ends between the two bearing blocks. To do this, the tension rods must be loosened and temporarily removed. After the tape change has been completed, the tension rods must be used again be excited. According to US 3,921,514, the prestressing force of the tension rods must be higher than the maximum pressing force. In a roller press with a shoe press unit, for example, this requirement can only be met with enormous effort because the maximum pressing force assumes very high values (order of magnitude 1000 kN / m). Thus, the already mentioned replacement of a felt belt or press jacket requires an enormously high amount of time.

In a construction according to US 3,921,514, the function of the tension rods is provided by screw connections which brace the bearing blocks with one another; This means that these screw connections must be pre-tensioned even when the roller press is not loaded. Such screw connections are extremely voluminous and expensive in highly loaded roller presses; assembling and releasing can only be carried out with enormous effort. In this context, it must be taken into account that such roller presses are preferably used in papermaking machines, the width of which in extreme cases can be up to 10 m. In particular, some roller presses are designed as shoe presses, in which the line force prevailing in the press nip can reach the order of magnitude of 1000 kN / m. To make matters worse, in many cases an endless felt belt (used to dewater the paper web) has to run through the press nip and that such a felt belt has to be exchanged for a new felt belt at certain intervals. Likewise, the rotating flexible (e.g. tubular) press element in shoe presses must be replaced from time to time.

The invention is therefore based on the object of further developing a roller press of the type mentioned in such a way that the disadvantages mentioned are avoided and a uniform treatment of the web across its width is always ensured.

The achievement of the object is characterized by the characterizing features of claim 1.

Explanation of some terms:

The "main axis" of a press unit can be, for example, the axis of rotation of a press roll shell or the longitudinal axis of the stationary support body, for example a shoe press unit (in the latter case, the axis of rotation can be arranged eccentrically to the main axis).

The "circumferential press element" can be a metallic press roll jacket, which is rotatable about a stationary support body and displaceable relative to it in the radial direction, or a press belt or a tubular press jacket, if it is a shoe press unit.

The "internal pressure device" can either be a semi-annular pressure chamber or a series of radially movable support elements or an elongated, radially movable press shoe.

According to the invention, the following is therefore proposed: The "a press unit", the bearing blocks of which are rigidly supported, stands on a frame, foundation or the like, or is suspended (by means of its bearing blocks) from a (e.g. vertical or horizontal) support. The "other press unit" can be arranged above, to the side or below the rigidly supported press unit; their weight is borne by the pedestals of the rigidly supported press unit. The term "rigidly supported" also includes the two-part bearing block construction with axial guide elements.

The bearing blocks of the two press units are coupled in pairs at each end of the roller press by means of releasable tension rods. These tension rods are the only ones Element for transferring the pressing force from the bearing block to the bearing block. Thus, the machine frames belonging to the roller press need only be dimensioned for the dead weight of the press units, but not for the transmission of the press force. It is also essential that the tension rods are easily detachable. According to the invention, the tension rods - in the unloaded state of the roller press, i.e. at zero pressing force - are not biased at all or only to a fraction (e.g. 1/5) of the maximum pressing force, and the bearing blocks of the one pressing unit are rigidly supported on the machine frame, while the bearing blocks are other press unit are movable along the press plane during operation.

A distinction must be made between two cases: If the press unit with the movable pedestals (along the press plane) is above the press unit rigidly supported on the machine frame, the movable pedestals rest at zero press force on the bearing blocks below the rigidly supported press unit. In the opposite case, the movable bearing blocks hang on the bearing blocks of the rigidly supported press unit located above them by means of the tension rods. In this case, the tension rods are prestressed by the weight of the lower press unit.

In addition, these tension rods are movable or flexible in a sense, so that the bearing blocks of the "other pressing unit" are movable parallel to the pressing plane relative to the bearing blocks of the rigidly supported pressing unit.

The difficulties encountered during maintenance or replacement work in an embodiment in accordance with US Pat. No. 3,921,514 can - thanks to the use of the easily detachable tension rods mentioned - be reduced and the necessary ones Activities are carried out in a relatively short time, so that the roller press is quickly operational again.

However, the inventors have recognized that a disadvantage of this proposed construction is that the two bearing blocks cannot be positioned exactly relative to one another, although guide jaws are provided on the machine frame. In other words, there is a risk that the main axis of the "other" press unit with the movable bearing blocks (at least temporarily) does not lie exactly in the press plane. As a result, the web is treated unevenly across its width and / or the roller jackets wear unevenly. It must therefore also be ensured that the main axis of the "other", i.e. the movable press unit always remains as precise as possible in the press plane during operation.

To solve the problem, there is now a further essential measure, namely that the bearing blocks are "centered" with one another with the aid of at least one guide surface which is parallel to the pressing plane and independent of the machine frame. As a result, the mobility of the bearing blocks of the non-rigidly supported press unit is maintained along the press plane. At the same time, however, it is ensured that the main axes of the two press units always remain exactly in the press plane during operation. Uneven web treatment or uneven wear of a roll shell is thus avoided.

From GB 845,160 a rolling mill having two rolls is known with the following features: each of the Both rollers are mounted in a bearing block via a rotatable bearing journal. Each of the bearing blocks has two large flat guide surfaces on its outer sides, with which it can slide in the vertical direction on corresponding flat guide surfaces of a machine frame. The lower bracket rests on the machine frame, which has a threaded spindle with a vertical axis of rotation above the upper bracket. The threaded spindle engages the upper bracket to adjust the height of the roll gap; a spreading device presses the upper bracket against the spindle. Additional tension rods are unloaded in this operating state and especially during the rolling process. The rolling pressure is therefore not transmitted from the bearing block to the bearing block via the tension rods, but rather via the threaded spindle and the machine frame. Compared to the subject of the application, there is a completely different type of machine. There it is provided from time to time to extend the two rollers together with the bearing blocks as a coherent assembly from the machine frame and to retract them (for example after a repair). In order to facilitate retraction, the outer guide surfaces of the two bearing blocks are held flush in that the bearing blocks have additional, directly contacting guide surfaces. This means that the pedestals are "centered" on one another - regardless of the machine frame. During the rolling process, however, it is not possible to keep the two rollers parallel to one another with the help of the additional guide surfaces alone. In this operating state, the mentioned outer guide surfaces, which interact with the machine frame, are essential.

In contrast to this, the following is characteristic of the construction according to the invention: on the bearing blocks alone or at least mainly such guide surfaces are provided which are independent of the machine frame. These guide surfaces are central in that area of the Roll press arranged, which (seen in the axial direction) is close to the press nip. During the normal operating state, in which the roller press is loaded and the tension rods are therefore under tension, the guide surfaces interact with the tension rods in such a way that the bearing blocks are held in the correct position with respect to one another with high accuracy. In other words, the transfer of the pressing force from the bearing block to the bearing block as well as the correct positioning of the "other" pressing unit (whose bearing blocks are movable) is completely independent of the machine frame.

In principle, it is sufficient if each bearing block has only a single guide surface. In the simplest case, there is only a single pair of guide surfaces at each end of the roller press, which e.g. by spring force (or with an inclined arrangement of the pressing plane) by gravity in mutual contact. It is only essential that each movable bearing block is positioned by a guide surface of the adjacent rigidly supported bearing block in such a way that its main axis is always in the pressing plane.

In a further embodiment of the invention, two pairs of guide surfaces parallel to the pressing plane are provided at each end of the roller press. For example, one bearing block can have a projection which engages in a recess in the other bearing block.

According to a further embodiment of the invention, however, a removable intermediate piece known per se is preferably provided between the two bearing blocks. However, this is now designed as a so-called guide piece; ie the side surfaces of the cuboid guide piece parallel to the pressing plane are now guide surfaces; because the guide piece engages - similar to one between a shaft and a hub arranged key - fits snugly into the recesses of the two pedestals to ensure the correct position of the movable pedestals. It is understood that the intermediate piece can be removed from the recesses, if necessary, for example for a change of felt.

Further refinements of the invention are specified in the additional subclaims. A e.g. Spreading device provided on the guide piece. This makes it possible to generate a small pretensioning force in the tie rods before the roller press is started up, in order to ensure the exact position of the tie rods and the movable bearing blocks with even greater accuracy.

Die Fig. 1

ist eine Ansicht auf eine Stirnseite der Walzenpresse.

Die Fig. 2

ist ein Längsschnitt entlang der Linie II der Fig. 1.

An embodiment of the invention is described below with reference to the drawing.

1

is a view of an end face of the roller press.

2

is a longitudinal section along the line II of Fig. 1st

The roller press shown has an underlying first press roller 1 and an overhead second press roller 3. The axes of these press rollers lie in a press plane E. The first press roller 1 has a rotatable roller jacket 1 a and a bearing journal 2 attached to it, which is mounted in a bearing block by means of a roller bearing 2a 5 (with lids 5a and 5b) rests. The bearing block 5 stands on a frame-shaped machine frame 15, of which some sections are indicated in FIGS. 1 and 2.

The upper, second press roll 3 is a so-called long-nip press roll. Your roller shell 3a is a tubular, flexible press jacket which is attached to two rotatable jacket support disks 3b. Each jacket support disk rests on the stationary bearing journal 4 of a stationary support body 4a, which extends through the interior of the roll jacket 3a. The support body 4a has a recess 4b relative to the lower press roll 1 and therein a piston-like and hydraulically actuated press shoe 4c. With its concave sliding surface, the latter presses the press jacket 3a against the lower press roll 1, in order to thereby form an extended press nip (in the running direction). A paper web to be dewatered runs through this together with at least one endless felt belt F. The upper press roll 3 rests (at each roll end) with the bearing journal 4 likewise in a bearing block 6. Between the two bearing blocks 5 and 6 there is a removable one on the bearing block 5 horizontal cuboid guide piece 9 is provided. The bearing block 6 of the upper press roller 3 rests on this when the roller press is in its unloaded state (ie when the recess 4b is depressurized). However, the loaded state is shown in which the press shoe 4c exerts a pressing force on the lower press roll 1. The resulting reaction forces are transmitted from the upper bearing block 6 to the lower bearing block 5 with the aid of flexible tension rods 7 and 8. The upper bracket 6 is lifted in this state by the distance p from the intermediate piece 9.

1, a flexible tension rod 7, 8 is provided on both sides of the pressing plane E. These tension rods and U-shaped intermediate pieces 10, 11 are inserted from the side into recesses in the bearing blocks 5 and 6. (The lower bearing block 5 has arms 5c and 5d, in which T-slots are provided.) Each of the flexible tension rods 7, 8 has a hammer head 20 at each end and is preferably designed in the manner of a leaf spring, the "leaf plane" of which is perpendicular to the pressing plane E. lies. As a result, the tension rods 7, 8 can deform when the support body 4, 4a is the second Press roll 3 experiences a (for example thermally induced) change in length and / or bends under the pressing force. Consequently, the upper bearing block 6 can be rigidly connected to the bearing journal 4; the axial sliding surface between these two components required in an older construction and a spherical sleeve can be dispensed with. However, it should be emphasized that the invention can also be used when the axial sliding surface and the spherical sleeve are present, the tension rods not having to be flexible. However, the following is essential: For the guide piece 9 already mentioned, a recess 25 is provided in the lower bearing block 5 according to FIG. 1, which has side surfaces parallel to the pressing plane E. Likewise, opposite the recess 25, a recess 26 is provided in the upper bearing block 6, which also has side surfaces parallel to the pressing plane E. The distances between the side surfaces mentioned are expediently the same in both recesses 25 and 26. Therefore, the cuboid intermediate piece 9 with its side surfaces 24, which are also parallel to the pressing plane E, fits into both recesses 25 and 26. The drawing shows this arrangement only at one of the two ends of the roller press. However, it is understood that the same arrangement is provided at the other end. Overall, it is thus achieved that the main axes 1A and 3A of the two rollers 1 and 3 and always lie exactly in the press plane E. This also applies if there is only a relatively loose connection between the bearing blocks 5, 6 when the roller press is relieved by means of the tension rods 7 and 8. The "centering" of the bearing blocks 5, 6 according to the invention can also be used with an inclined arrangement of the roller press.

Deviating from the drawing, it may be necessary to dispense with the fact that the guide piece 9 can be removed; in this case it can be used together with the bearing block 5 form a one-piece component; in other words: it can form a nose formed on the bearing block 5. According to another alternative, not shown, the guide piece is divided by a horizontal parting line into an upper and a lower section, for example only the lower section performing the guiding function and therefore engaging in both recesses 25 and 26. The height of the upper section can be adjusted using a spreading device.

However, the embodiment shown is preferred with the following features: An axis of rotation 27 perpendicular to the pressing plane E is fixed in the upper bearing block 6. On this the head 28 of a threaded spindle 23 is rotatably mounted so that the axis of the threaded spindle is always in the pressing plane E (or at a short distance from it and parallel to it). The threaded spindle 23 extends into a bore 21 provided in the guide piece 9. A spindle nut 22 can come into contact with the guide piece 9 by turning on the spindle 23. As a result, in the unloaded state of the roller press, a slight pretension can be applied to the tension rods 7, 8, which is retained if the pressing force is temporarily reduced to zero during operation. In this case, the bearing block 6 does not rest directly on the guide piece 9, but indirectly via the axis of rotation 27, spindle 23 and spindle nut 22.

If a new felt F has to be drawn into the roller press, the procedure is as follows: First, the upper press roller 3 is raised somewhat with the aid of an eyelet 12 and a hydraulic cylinder 16 which hangs on the machine frame 15, so that the spindle nut 22 is twisted open the spindle 23 can be released from the guide piece 9. Then the press roll is lowered until the bearing block 6 rests directly on the guide piece 9. Now the tension rods 7, 8 and intermediate pieces 10, 11 can be removed will. For example, the tension rod 8 is pushed onto a bolt 14 which is fastened to the machine frame 15. Now the upper press roll 3 is raised again with the help of the hydraulic cylinder 16. Thus, the guide piece 9 can now be swiveled out laterally upwards together with the spindle 23, as shown in FIG. 2 with dash-dotted lines. The guide piece 9 remains permanently connected to the spindle 23 with the aid of a small bolt 29 which extends transversely through the guide piece and the spindle.

The spreading device consisting of the parts 22, 23, 27, 28 can also be arranged below the guide piece 9 in the bearing block 5, so that the guide piece is pivoted out laterally downward.

Claims (6)

1. Roller press, preferably for the treatment of a continuous sheet, for example a sheet of paper, with two pressing units (1, 3), of which the main axes lie in a pressing plane (E) and which together form apressing nip through which the sheet travels, also with the following features:

   a) one of the two pressing units (3) has a stationary carrying member (4, 4a) extending through a rotatable roller shell (3a) and an internal press-on device (4b, 4c) for the radial movement of the roller shell and for the production of a pressing force acting on the sheet in the pressing nip;

   b) at each end of the roller press the two pressing units (1, 3) are supported in bearing blocks (5, 6) which are coupled to one another in pairs by detachable tension rods (7, 8) serving to transfer the pressing force from bearing block to bearing block;

   c) the bearing blocks (5) of one of the two pressing units (1) are supported directly on a machine frame (15), foundation or the like and carry at least a proportion of the weight of the other pressing unit (3);

   characterized by the following features:

   d) the tension rods (7, 8) are pretensioned with a pressing force of zero to at most a fraction of the maximum pressing force;

   e) one bearing block (6) of the bearing blocks (5, 6) coupled to one another in pairs is movable relative to the other bearing block (5) so this bearing block (6), in the loaded state of the roller press, is deflected relative to the other bearing block (5) with respect to its position in the unloaded state of the roller press by a distance (p) along the pressing plane (E);

   f) the bearing blocks (5, 6) are guided relative to one another by means of at least one pair of guide surfaces (24, 25; 24, 26), the guide surfaces lying parallel to the pressing plane (E) and being independent of a stationary machine frame (15), mounting or the like;
2. Roller press according to Claim 1, characterized by the following features:

   a) a removable guide member (9) is arranged between the bearing blocks (5, 6) coupled to one another in pairs;

   b) the bearing blocks (5, 6) coupled to one another in pairs each have a recess (25, 26) - as viewed in the axial direction -, the guide member (9) engaging in the recesses with its lateral faces (24) parallel to the pressing plane (E).
3. Roller press according to Claim 1 or 2, characterized in that a spreader (22, 23) is provided between the bearing blocks (5, 6) coupled to one anotherin pairs.
4. Roller press according to Claim 3, characterized in that one of the two bearing blocks (6) coupled to one another in pairs is connected to the guide member (9) via a threaded spindle (23).
5. Roller press according to Claim 4, characterized in that the guide member (9) has a bore (21) into which the free end of the threaded spindle (23) penetrates and in that a spindle nut (22) which can be applied to the guide member (9) by rotation is located on the threaded spindle.
6. Roller press according to Claim 4 or 5, characterized in that the threaded spindle (23) is pivotal together with the guide member (9) round a pivot pin (27) perpendicular to the pressing plane (E) and fixed in one of the bearing blocks (6) coupled to one another in pairs.

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