Paper making and fiber liberation – Apparatus – Running or indefinite length product forming and/or treating...
Reexamination Certificate
1999-06-30
2001-03-13
Silverman, Stanley S. (Department: 1731)
Paper making and fiber liberation
Apparatus
Running or indefinite length product forming and/or treating...
C162S363000, C162S368000, C162S205000, C162SDIG007, C034S114000, C034S115000, C034S117000, C029S254000
Reexamination Certificate
active
06200427
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a suction roll for the formation or treatment of a material web, such as, in particular, a paper, card or textile web. The suction roll includes an outer suction roll jacket formed by a perforated, rotating, hollow cylinder and a non-perforated support body which passes through the suction roll jacket. The suction roll jacket is supported on the support body, at at least one point of its axial extent, in particular against its own weight, against the suction force, against the tensile force of an outer, recirculating belt, and/or against a pressing force acting from the outside.
2. Discussion of Background Information
The previously known suction rolls of this kind have, among other things, the disadvantage that the line force is restricted to a relatively low value. These rolls are thus, for example, not suitable for use in connection with deflection compensated rolls.
In a suction roll of the initially named kind known from DE-C-227223 in which a plurality of longitudinal cells subjected to axial suction are formed between a screen-like perforated outer jacket and an inner jacket, the inner jacket is secured by spiders and hubs to a rotating shaft.
In FR-A-2364291 a roll subjected to suction from the outside is described which includes a hollow, deflection compensated cylinder which is supported via a sliding shoe on an inner stationary carrier, which has through-going radial bores with a relatively large spacing from one another which communicate with longitudinal grooves. The roll is also provided with an outer jacket having longitudinal grooves which communicate with those of the deflection compensated cylinder, and thus with the inner space of the deflection compensated cylinder. In another embodiment of a roll subjected to suction from the outside, known from this FR-A-236429 1, a non-perforated roll jacket provided with grooves is supported via a pressure medium chamber on an inner stationary carrier.
SUMMARY OF THE INVENTION
The object of the invention is to provide a suction roll of the initially named kind which can be used without problem, in particular also in connection with associated deflection compensated rolls, and -which is in particular also suitable for the production of higher pressing forces. Moreover, the suction roll should be capable of being used in advantageous manner, in particular also as a suction breast roll, or forming roll or screen suction roll.
This object is satisfied in accordance with the invention in a suction roll having sealing ribs which extend radially between the support body and the suction roll jacket, and also axially over the full length of the suction roll jacket. The support body has an axially extending, throughgoing bore concentric to the outer suction roll surface. An axially ex-tending, rotationally fixed yoke passes through this bore, and is supported at its two ends outside of the support body on a frame. The support body is supported at the yoke by at least one hydrostatic and/or hydrodynamic support element, with it preferably being possible to influence the bending line of the support body.
An alternative solution proposed by the invention for a suction roll without ribs is characterized in that the support body has a right cylindrical outer contour and also a throughgoing axial bore concentric to the latter. An axially extending, rotationally fixed yoke passes through this bore and is supported at its two ends outside of the support body on a frame. The support body is supported at the yoke by at least one, preferably hydrostatic and/or hydrodynamic support element on the yoke, and it is preferably possible to influence the bending, line of the support body. The support body eccentrically contacts the inner circumference of the suction roll jacket. The outer circumferential speed of the support body is at least substantially the same as the inner circumferential speed of the suction roll jacket.
As a result of this design, significantly higher pressing forces can be produced with a minimum effort. In particular, it is also possible to associate one or more shoe pressing units with the suction roll, by which a higher line force can, if necessary, be achieved and which can in particular lie above 200 kN /m. Moreover, the suction roll of the invention can in particular also be used as a suction breast roll or as a forming suction roll or as a screen suction roll. Advantageous possibilities of use thus also result, in particular in conjunction with the formation of pressure zones in forming cylinders. Moreover, with this enlarged scope of use in the forming region, the screen tensions and the associated roll deflection and the adjustment of the screen tension and of the screen running length, which may be possible by a Nipco control (deflection compensated roll) can be taken into account over the full machine width.
With respect to the second alternative, the advantages named in the following also result, amongst other things. Thus, a high loadability is achieved as a consequence of the direct support of the jacket, above all with broad, broad-nip counter-rolls, and the line force can, for example, be larger than
200
kN/m. Through the zone control, a regulatable deflection or contour of the nip profile is possible, due to direct support with a flexible jacket of the support body formed by a Nipco or deflection compensated roll and also a more flexible suction roll jacket. Since the suction roll jacket can have a thinner wall thickness as a result of the direct support without ribs, the suction roll jacket is less expensive in total. Moreover, because less hole air has to be pumped away as a consequence of the lower wall thickness of the suction roll jacket, lower energy costs arise for the vacuum to be produced. The manufacturing costs are further reduced in that a less expensive Nipco jacket can also be used for the support body in addition to the thin suction roll jacket, and no form of ribs or other webs are necessary between the suction roll jacket and the support body.
With the ribs which are provided in the first alternative, a type of cellular suction roll arises, and end face suction and/or also a different type of suction can be provided. The support body is in particular supported by the different deflection compensated rolls.
In an embodiment of the suction roll of the invention formed in accordance with the first alternative, which is referred in practice, at least one, non-rotating connection is provided. At least at one roll end, with sectors formed between the suction roll jacket and the support body by the ribs alternately lying opposite to the connection as a consequence of the rotation of the roll. The sector or sectors which respectively lie opposite to the non-rotating connection is sealed relative to the connection, and is connected via the latter to a pressure or vacuum source, so that different pressures result for the sectors spread about in the circumferential direction.
In certain cases a non-uniform suction can consciously be provided over the width. Thus, it can in practice, for example, transpire that suction only takes place at the edge. Moreover, an external suction can be provided in combination with end face or internal suction.
In an expedient embodiment, the sectors formed by the ribs between the suction roll jacket and the support body are subdivided in the direction of the roll axis by at least one radially extending partition wall into at least two axial sections, which can be separately subjected to pressure.
In certain cases, it is expedient if at least one non-rotating connection is respectively provided at the two roll ends. If the sectors are subdivided in the direction of the roll axis by at least two axially spaced apart partition walls, at least three axial sections can be separately subjected to pressure. In this connection, it is expedient if the sectors formed between the suction roll jacket and the support body in at least one axially central roll zone are connectable via connection lines to
Esslinger Klaus
Kotitschke Gerhard
Mayer Wolfgang
Meschenmoser Andreas
Mirsberger Peter
Halpern Mark
Silverman Stanley S.
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