Winding – tensioning – or guiding – Convolute winding of material – With particular drive
Reexamination Certificate
1999-03-09
2001-04-17
Walsh, Donald P. (Department: 3653)
Winding, tensioning, or guiding
Convolute winding of material
With particular drive
C242S541300, C242S908000, C242S534000
Reexamination Certificate
active
06216976
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a reel winding device for a material web reel that includes a reel lightening device with a blow box coupled to a compressed air supply, and to a process for lightening a material web reel in a winding and/or unwinding device. Further, the features of the present invention may be utilized both during winding and unwinding of material web reels. In both cases, similar problems may be solved in a same manner.
2. Discussion of Background Information
In order to reduce setup times, those who work with paper web reels, e.g., printing plants, want increasingly larger paper web reels, i.e., a larger paper web supply. Currently, the trend in the industry is to produce web reels having widths of more than 3 meters and reel diameters of more than 1.5 meters.
However, as the web reel widths become relatively large, the increased weight of the reel, when a certain reel diameter is exceeded, results in sagging of the paper web reel. In this case, the core, which is usually designed as a pasteboard tube, is no longer capable of providing the necessary rigidity.
This sagging during winding has been countered in the prior art by supporting the paper reel from beneath. However, this arrangement requires that the paper reel rest with a certain bearing force on the support, and the bearing pressure determines reel hardness. Thus, because the weight of the reel increases during winding, there is a danger that the reel hardness will increase from the inside out, which is an undesirable hardness pattern.
To avoid affecting reel hardness in this manner, the prior art has proposed to support the reel via an air cushion. In this case, the reel weight is distributed over a relatively large surface such that the bearing pressure remains low.
A blow box, which is fed compressed air from a compressed air supply, is used to generate the air cushion. The blow box is pivoted toward the paper reel as soon as the reel diameter exceeds a specific value of, e.g., approximately 500 mm. To prevent damage to the paper reel, a gap must be maintained between the reel and the blow box. However, this also results in significant energy losses due to escaping compressed air. Further, the pressure relationships in the blow box and, thus, the extent of lightening are permanently altered, particularly since the weight of the paper reel is subject to change as a result of the winding or unwinding.
SUMMARY OF THE INVENTION
The present invention provides a device for reel lightening by compressed air that keeps energy consumption low.
The present invention provides a reel winding device of the type generally discussed above that includes a compressed air supply and a regulating device that regulates a gap between the material web reel and a blow box to a predefined set point.
According to the features of the present invention, the formation of the gap between the material web reel and a blow box, in contrast to the prior art, is not left to chance, i.e., the gap is regulated by the regulating device. Thus, through regulation, it may also possible to take the changing weight of the reel into account. For example, with a smaller diameter of reel and a correspondingly lower reel weight, the necessary counter pressure which is generated by the air pressure is less than with a larger reel diameter, thus, energy savings result. Moreover, it is not necessary to always work with full air pressure. The gap size may be set to a relatively low value, e.g., approximately 0.5 mm. Since a regulating device in the compressed air supply can operate relatively quickly, it may be substantially ensured that, even with these small gap widths, an inadvertent touch-down of the material web reel onto the blow box may be substantially eliminated. With small gaps, the compressed air losses may also less, and it may be observed that significantly more stable pressure relationships may be obtained with such regulation.
It may be preferable to include a sensor device coupled to the regulating device to determine the size of the gap between at least one edge of the blow box and the peripheral surface of the material web reel, i.e., in the peripheral direction of the material web reel. This gap may be primarily utilized for leaking air. Moreover, it may deliver a reliable regulating variable with all relevant reel diameters. At smaller diameters, the material web reel may naturally dip deeper into the blow box than at higher reel diameters. If the gap at the edge of the blow box is monitored in the peripheral direction, then the dip does not affect the gap measurement. The sensor device utilizes at least one distance sensor, and possibly, a distance sensor for both edges. Distance sensors of this type are known, and they may be designed contact free, e.g., as optical sensors, or they may operate mechanically, e.g., a sensing roller attached to the blow box that abuts the periphery of the material web reel. A deflection of the sensing roller relative to the material web reel may then yield information related to the distance of the material web reel from the edge of the blow box.
It is also be preferable for the sensor device to be composed of a sensing roller that extends over the entire axial extent of the blow box. In this way, the sensor device may also provide an additional sealing function in addition to the measurement function. This may be particularly advantageous when such a sensing roller is used on both sides of the blow box.
Further, because the greatest amount of reel sag occurs in the axial center of the material web reel, the blow box may have a shorter axial dimension than the material web reel. Consequently, it suffices in most cases to support the material web reel in this zone, i.e., on both sides of the axial center. Accordingly, the compressed air supply may be restricted to a smaller width, which also reduces energy consumption. It is also easier to provide adequate stability for the desired gap between the blow box and the reel on the shorter length.
When the reel assumes the desired gap with the blow box, the compressed air may leak on the ends of the blow box, which would render regulation more difficult under certain circumstances, and the gap may change as the reel diameter changes. Accordingly, the present invention may also preferably include sealing belts may positioned on the ends of the blow box to endlessly circulate, and an upper strand of the sealing belts may be arranged to abut the material web reel. In this manner, leakage at the end of the blow boxes may be alleviated in a simple manner by utilizing the sealing belt, which is stretched around a circumferential portion of the material web reel, at least as far as the blow box extends in the peripheral direction. The sealing belt merely needs to have a thickness which covers the gap between the blow box and the material web reel at all reel diameters, which is possible with no problem. Since the sealing belt circulates with the material web reel, there is no relative movement between the sealing belt and the surface of the material web reel, thus, no frictional effects which could result in damage to the material web occur. In this case, it is merely necessary to seal the gap between the sealing belt and the ends of the blow box. However, this gap, when it exists, has at least a virtually constant flow-through characteristic, such that it is possible to consider it in the regulation as well.
However, it may be preferable for the sealing belts to abut the ends of the blow box. In this case, there is a moving seal between the blow box and the sealing belts which may not completely prevent escape of compressed air, but does keep the resulting losses low.
It may particularly preferable to provide a pressing device that acts in the axial direction to abuts the sealing belts. Thus, the sealing belts may be pressed with their natural stress against the ends of the blow box, which may improve impermeability.
It may be preferable to provide, at least on a side of the sealing belt positioned a
Greenblum & Bernstein P.L.C.
Voith Sulzer Papiermaschinen Patent GmbH
Walsh Donald P.
Webb Collin A
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