Roll or roller – Concentric layered annulus – Specific composition
Reexamination Certificate
2000-03-30
2001-11-13
Rosenbaum, I Cuda (Department: 3726)
Roll or roller
Concentric layered annulus
Specific composition
C492S053000, C492S059000
Reexamination Certificate
active
06315704
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATION
The present application claims priority under 35 U.S.C. §119 of German Patent Application No. 199 14 708.6, filed Mar. 31, 1999, 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 relates to a process for producing a resilient roll having a hard roll core (such as a metal) and a resilient covering layer. In forming the covering layer, an inner connecting layer is first applied to the roll core and then an outer functional layer is applied to the connecting layer. Furthermore, the invention is directed towards a roll, in particular for smoothing paper webs, having a hard roll core (such as a metal), which is provided on its outer periphery with a resilient covering layer. The resilient covering layer can comprise a radially outer functional layer and a radially inner connecting layer for connecting the functional layer to the roll core.
2. Discussion of Background Information
Resilient rolls of this type are used, for example, in the calendering of paper webs. An elastic roll and a hard roll form a press nip, through which the paper web to be processed is directed. While the hard roll has a very smooth surface, consisting, for example, of steel or hard cast iron, and is responsible for smoothing that side of the paper web which faces it, the resilient (i.e., second) roll, acting on the opposite side of the paper web serves to compact the paper web and then renders it uniform in the press nip. The resilience of the second roll therefore prevents a too intensive compaction of the paper web, which would lead to a specky appearance of the paper web.
The rolls are of the order of from about 6 to 12 m long and of from about 800 to 1500 mm in diameter. The rolls withstand line forces of up to approximately 600 N/mm and compressive stresses of up to approximately 50 N/mm
2
. Since the tendency or trend in paper manufacture is for calendering to be carried out on-line (i.e., the paper web leaving the papermaking machine or coating machine is immediately led through the paper smoothing or calendering device), higher requirements than previously are placed on the rolls of the smoothing device, particularly with respect to their temperature resistance. The high transport speeds of the paper web, necessitated by on-line operation, and the associated high rotational speeds of the calender rolls, increase their alternating flexure frequency, which in turn leads to increased roll temperatures. These high temperatures, produced in on-line operation, lead to problems which, in the case of known resilient rolls, can lead to the destruction of the synthetic covering of the roll. On the one hand, in the case of known synthetic coverings, maximum temperature differences of about 20° C. over the width of the roll are permissible. On the other hand, the polymers normally used for the coating have a significantly higher coefficient of thermal expansion than the steel or hard cast iron rolls normally used. Accordingly, as a result of an increase in the temperature, high axial stresses occur between the steel or hard cast iron roll and the synthetic coating connected to it.
As a result of these high stresses, associated with heated locations, occurring at certain points or regions within the synthetic coating, so-called hot spots can occur, at which the separation or even the bursting of the synthetic layer takes place.
These hot spots tend to occur in particular when, in addition to the mechanical stresses and the relatively high temperature, there are crystallization points in the form of, for example, faulty adhesive bonds, deposits or above-average bulges in the resilient covering. These bulges can occur, for example, as a result of creases or foreign bodies on the paper web. In such cases, the temperature at these crystallization points can rise from a normal of about 80° C. to 90° C. to more than 150° C., which results in the aforementioned destruction of the synthetic layer.
SUMMARY OF THE INVENTION
The present invention relates to a process for producing a resilient roll having a hard roll core and a resilient covering layer. The process includes forming the covering layer by applying a radially inner connecting layer to the roll core and then applying a radially outer functional layer to the connecting layer. In forming at least one of the connecting layer and the functional layer, glass fibers and carbon fibers are simultaneously wound onto the roll core.
Further, the glass fibers and the carbon fibers are wound onto the roll core in glass fiber and carbon fiber rovings. Each roving comprises a plurality of fibers of identical type positioned beside one another. During the winding, a plurality of glass fiber and carbon fiber rovings positioned beside one another and adjoining one another are simultaneously wound onto the roll core to form a roving layer.
According to a further feature of the present invention, in forming at least one of the connecting layer and the functional layer, a number of roving layers are wound over another one.
Additionally, before being wound onto the roll core, the glass fibers and carbon fibers are surrounded with a matrix material, the matrix material comprising a resin/hardener combination. The glass fibers and carbon fibers can also be drawn through a resin/hardener bath.
According to another feature of the invention, the glass fibers and the carbon are wound substantially dry onto the roll core and have a soft matrix material applied to glass fibers and carbon fibers while the glass fibers and carbon fibers are being wound onto the roll core. The glass fibers and carbon fibers are completely embedded in the matrix material.
According to yet another feature of the invention, the glass fibers and carbon fibers are wound substantially dry onto the roll core and have a soft matrix material applied to the glass fibers and carbon fibers, after the glass fibers and carbon fibers have been wound onto the roll core. The glass fibers and carbon fibers are completely embedded in the matrix material. The matrix material can be a resin/hardener combination.
According to a further feature, the matrix material can be one of a thermosetting polymer and a thermoplastic polymer. Further, the fiber content of the connecting layer can be about 40 to 70% by volume. Yet further, the fiber content of the connecting layer can be about 50 to 60% by volume. Preferably, the fiber content of the connecting layer can be about 55% by volume.
In addition, the fiber content of the functional layer can be about 5 to 20% by volume. Preferably, the fiber content of the functional layer can be about 8 to 12% by volume.
The present invention also relates to a roll, for use in smoothing paper webs. The roll can have a hard roll core provided with a resilient covering layer. The covering layer can include a radially outer functional layer and a radially inner connecting layer that connects the functional layer to the roll core. Further, at least one of the connecting layer and the functional layer can be made up of a mixture of glass fibers and carbon fibers, which are embedded in a soft matrix material and are distributed substantially uniformly over the length of the roll core. The mixture ratio of glass fibers to carbon fibers can be between about 60/40 and about 90/10.
The matrix material can be a polymer. Further, the matrix material can be a resin/hardener combination. The roll core can be a metal roll core.
According to a feature of the invention, the mixture ratio of glass fibers to carbon fibers can be about 70/30.
REFERENCES:
patent: 3490119 (1970-01-01), Fukuyama et al.
patent: 4466164 (1984-08-01), Tadokoro et al.
patent: 5324248 (1994-06-01), Quigley
patent: 5334124 (1994-08-01), Ohno
patent: 5387172 (1995-02-01), Habenicht et al.
patent: 5776043 (1998-07-01), Kato et al.
patent: 5784961 (1998-07-01), Lorig et al.
patent: 5790926 (1998-08-01), Miozoe et al.
patent: 5797322 (1998-08-01), Lorig et al.
patent: 5836860 (1998-11-01), Watanabe
Cuda Rosenbaum I
Greenblum & Bernstein P.L.C.
Voith Sulzer Papiertechnik Patent GmbH
LandOfFree
Roll for smoothing paper webs does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Roll for smoothing paper webs, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Roll for smoothing paper webs will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2580985