The invention concerns a device for guiding a strip, especially a metal strip, by means of one or more rolls. In this regard, the roll force that acts on the rolls during the guidance of the strip, i.e., under load, is measured.
Devices of this type are known in the prior art, e.g., from European Patent EP 0 539 784 B2, which discloses a continuous casting plant in which the rolls of a strand guide apparatus are adjusted by means of hydraulic cylinders. To measure the mechanical loads that act on the individual rolls of the strand guide apparatus during its operation, a load cell or force gauge is assigned to each roll. In this regard, the load cell is mounted between the bearing block in which the roll is supported and a segmented crosshead.
Moreover, the following documents disclose prior-art devices of the aforementioned type:
In practical terms, all of these documents disclose a device for guiding a metal strip with a bearing block, in which a roll for guiding the strip is rotatably supported. In addition, the device comprises a sensor unit for detecting deformation of the bearing block during the guidance of the strip and an evaluation unit for computing the roll force that acts on the roll from the deformation of the bearing block that is detected by the sensor unit.
Proceeding from this prior art, the objective of the invention is to further develop a known device for guiding a metal strip in such a way that, on the one hand, the sensor unit and/or the evaluation unit are located spatially close to the location of the deformation that is to be measured and that, on the other hand, they are protected from environmental influences.
This objective is achieved by the object of device claim 1. In practical terms, in accordance with the invention, the bearing block, whose deformation is being measured, has a cavity or a recess for holding the sensor unit and/or the evaluation unit.
The cavity in the bearing block offers the advantage that when the sensor unit and/or the evaluation unit is mounted in the cavity, on the one hand, it is then located spatially close to the location of the deformation of the bearing block that is to be measured and, on the other hand, it is protected there in the bearing block from environmental influences, especially moisture.
The term “strip” is used very broadly in the context of the invention. It basically means strips of any material and any cross section, including cables and threads. However, the term especially means metal strips, including, specifically, slabs.
The term “roll” is also used very broadly in the context of the invention. In principle, therefore, rolls may also be wheels or guide pulleys. However, the term is applied here especially to a strand guide roll of a strand guide apparatus, a roll of a rolling stand, or a roll of a looper or other device for the temporary storage of metal strip.
The claimed indirect method for measuring the roll force offers the advantage that it is very easily installed and yields reliable measurement results for the roll forces for an extended period of time.
A design of the sensor unit in the form of an ultrasonic sensor, an eddy-current sensor, or an optical gap sensor offers the advantageous possibility of contactless measurement of the deformation, which requires only minor design measures on the bearing block.
If the bearing block has a suitable weak point, it is advantageous if its deformation during the guidance of the strip can be easily detected by the sensor unit as representative of the deformation of the bearing block.
It is especially simple to design the weak point in the form of a slot. It is then advantageous for the sensor unit to be designed as a simple and inexpensive gap sensor, which then detects the deformation of the bearing block under load in the form of constriction of the slot.
Advantageous embodiments of the device are objects of the dependent claims.
The specification is accompanied by three figures.
The invention is described in detail below with reference to the specific embodiments illustrated in the drawings. In all of the figures, elements that are the same are identified by the same reference numbers.
The evaluation unit 144 then uses this deformation to compute the sought force F acting on the roll under load.
In this regard, however, it is necessary to consider that the geometric variations of the specified order of magnitude occur only in the area of the artificially incorporated weak point; otherwise, the deformations are typically of a much smaller order of magnitude that are barely still measurable. In this respect, the weak point offers a suitable means of transforming the deformation of the bearing block to a magnitude that can be measured or of rendering the deformation visible. On the one hand, the weak point must be suitably designed for this purpose. On the other hand, however, it is also necessary to guarantee that the bearing block 120 is not weakened to an unacceptable degree by the weak point, but rather, e.g., in the case of an embodiment of the device as a strand guide apparatus, to guarantee that the deformation of the weak point remains so small that the strand shell of a slab is not subjected to an overload due to the change in the roll position under load.
Number | Date | Country | Kind |
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10 2006 027 066.5 | Jun 2006 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2007/004753 | 5/30/2007 | WO | 00 | 12/10/2008 |