Presses – With additional treatment of material – Heating – cooling – or drying
Reexamination Certificate
1999-07-15
2001-10-23
Gerrity, Stephen F. (Department: 3721)
Presses
With additional treatment of material
Heating, cooling, or drying
C100S16200R, C100S16300R
Reexamination Certificate
active
06305280
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority under 35 U.S.C. §119 of German Application No. 198 32 067.1, filed on Jul. 16, 1998, the disclosure of which is expressly incorporated by reference herein in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to a calender for use with a material web, such as, for example, a paper web or similar material, in which a frame holds at least one roll stack having a plurality of rolls, and in which an end roll is designed as a sag compensation roll having a jacket supported on a non-rotatably held bracket by a sag compensation device.
2. Discussion of Background Information
A calender for use with material webs is disclosed, for example, in German Patent DE 196 33 671 A1. A calender of this patent has two roll stacks, in which each roll stack has five rolls. The rolls are arranged one above the other in a common vertical plane and passed through one after another by a material web, such as, for example, a paper web. An upper roll is stationarily attached to a frame, while a lower roll is attached to a slide that is displaced by a hydraulic cylinder in a direction of the roll stack when subjected to a load. Each jacket of an associated sag compensation roll, of a plurality of sag compensation rolls, is mounted at its end on an associated bracket. The brackets are held on the roll frame (or on the slide) in a stationary manner.
However, any change in the load results in a change in a compressive stress in all the nips of the roll stack.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to develop a calender for use with a material web that offers improved processing capabilities, so that, for example, a change in the load will not result in a change in a compressive stress in the nips of the roll stack.
The object of the present invention is achieved by fixedly mounting an intermediate roll, adjacent to an upper sag compensation roll, on a frame of the calender. The upper sag compensation roll permits a compressive stress in an upper nip to be independently adjusted with respect to any compressive stress in any nips located below the upper sag compensation roll.
By such a design, two regions in the roll stack are created. A compressive stress in a first region (e.g., an upper nip) may be adjusted independently from a compressive stress in a second region (e.g., a remaining nip). Thus, it is possible to operate the calender with a maximum compressive stress in the upper nip, which results in a significant improvement in a glazing of the material web, particularly when the web is introduced through the first nip.
According to the disclosed calender of the present invention, the stack has five rolls. However, it is understood that the stack may include a different number of rolls, such as, for example, eight rolls, without departing from the spirit and/or scope of the invention.
According to a feature of the invention, two end rolls are of the jacketed lift type. Brackets associated with the two end rolls are fixedly mounted to the frame of the calender. As a result, a load is equally applied to the roll stack from both ends. Additionally, the present invention requires only one spare roll for both end rolls.
A typical sag compensation roll of the jacketed lift type is disclosed in, for example, German Patent DE 30 04 913 C2. In the present invention, the sag compensation roll comprises an upper roll and a lower roll of a roll stack. When the calender is operated, the jacket of one end roll is moved until it reaches a stop, such that the position of the jacket is fixed relative to the frame.
Intermediate rolls located below an upper intermediate roll are mounted on levers, and pivot about frame-stationary pivot axes. The intermediate rolls follow a change in load by the lower sag compensation roll. In addition, the nips located below the upper nip automatically open when the lower sag compensation roll is lowered.
Two similar roll stacks are arranged one after another in the disclosed invention. The two roll stacks are arranged in a direction of a web travel, such that the upper intermediate roll of the first roll stack comes into contact with one side of the material web and the upper intermediate roll of the second roll stack comes into contact with a second side of the material web. This allows the paper web to be processed in such a way that roughly the same processing results appear on both sides of the material web. Further, when the similar roll stacks have end rolls of the jacketed lift type, only one spare roll is required for both stacks.
According to an object of the invention, a calender for use with a material web comprises a frame, at least two roll stacks, and an adjusting device. Each roll stack of the at least two roll stacks has a plurality of rolls, end rolls of the plurality of rolls forming sag compensation rolls with a jacket. The sag compensation rolls are supported on a bracket that is afixed to the frame. It is noted that the bracket of the disclosed invention is non-movable. An intermediate roll, fixedly mounted to the frame, is positioned adjacent one of the sag compensation rolls. The adjusting device adjusts a sag compensation roll in order to adjust a compressive stress in a first nip, such that the compressive stress in the first nip is adjusted independently from a compressive stress adjustment of a second nip.
According to a feature of the invention, the end rolls comprise jacketed lift type rolls that are fixedly mounted to the frame by the bracket.
Another feature of the invention is that the intermediate roll is located below an upper intermediate roll that is attached to a pivotally mounted lever.
An advantage of the invention is that the at least two roll stacks are arranged one after another in a direction of travel of the material web, such that an intermediate roll of a first roll stack comes into contact with one side of the material web, while an immediate roll of a second roll stack comes into contact with an other side of the material web.
According to another object of the invention, a calender is disclosed for use with a material web, in which the calender has at least one roll stack with at least four rolls, end rolls of the at least one roll stack being designed as sag compensation rolls with a jacket non-rotatably supported on a bracket. The calender additionally comprises an intermediate roll that is positioned proximate an upper sag compensation roll, and an adjusting device that adjusts a compressive stress in an upper nip independently of a compressive stress in a remaining nip.
A still further object of the invention concerns a calender for use with a material web, in which the calender comprises a roll stack, and an adjusting device. The roll stack comprises an upper roll, a lower roll, and at least one intermediate roll. An upper nip is formed between the upper roll and the intermediate roll. A second nip is formed between the lower roll and the intermediate roll. The adjusting device adjusts a compressive stress in the first nip independently from a compressive stress adjustment of the second nip.
In an advantage of the current invention, the at least one intermediate roll comprises a plurality of intermediate rolls, with additional nips being formed by the plurality of intermediate rolls. The compressive stress in the upper nip is adjusted independently from a compressive stress adjustment of the additional nips. The compressive stress in the upper nip is adjusted independently from a compressive stress adjustment of said lower nip and said additional nips.
According to another advantage of the invention, at least one of the upper roll and the lower roll comprises a sag compensation roll. The sag compensation roll may comprise a jacketed lift type sag compensation roll.
In a still further advantage of the invention, the calendar comprises a frame, and a mounting device that fixedly mounts the intermediate roll to the frame. Alternatively, a lever pivotally mounts the intermedia
Gerrity Stephen F.
Greenblum & Bernstein P.L.C.
Voith Sulzer Papiertechnik Patent GmbH
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