GB1587420A

GB1587420A - Strip mill

Info

Publication number: GB1587420A
Application number: GB48299/77A
Authority: GB
Original assignee: ASEA AB
Current assignee: ABB Norden Holding AB
Priority date: 1976-11-22
Filing date: 1977-11-21
Publication date: 1981-04-01
Also published as: DE2750047A1; JPS5365771A; SE7613004L

Description

(54) IMPROVED STRIP MILL (71) We, ASEA AKTIEBOLAG, a Swedish Company of Vasteris, Sweden, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a strip mill of the kind described in our British Patent Specification No. 1,156,705.

The strip mill described in Specification No 1,156,705 comprises a billy roll, or bending roll, which is divided in to a number of zones located axially one after the other, each zone comprising at least two pressure-sensitive regions which are arranged opposite to each other in at least one axial plane. Each of these regions comprises a pressure-sensitive transducer which is arranged in the vicinity of the surface of the bending roll and which is of the type emitting an electrical output signal which is a function of the force by which a strip running across the bending roll influences the transducer.The output signals from the transducers are supplied to a signal processing unit, in which the signals from the various measuring zones are put together in different ways, dependent on what information is desired regarding the strip, for example the distribution of the strip tension along the bending roll.

An uneven distribution of the strip tension along the bending roll signifies that the roller gap is incorrectly adjusted to the profile of the strip thickness used. To correct such irregularities it is known to resort to certain measures such as cooling the rollers or changing the mechanical cambering of the rollers. Since the speed of the rolled metal through one pair of rolls is high, a change in the distribution of the strip tension must be rapidly adjusted to correct the fault occurring. The regulating devices necessary to effect a correction must therefore be automatically controlled, suitably from said signal processing unit. Practical examples of regulating devices are nozzles for applying a coolant such as a gas or a liquid onto the rolls.These nozzles are then arranged in a number of zones across the direction of rolling, one or more nozzles being located in each regulating zone.

According to the present invention, a strip mill comprising a bending roll for measuring the variation of the strip tension across the strip width, said bending roll being divided into a plurality of measuring zones, each of which emits a measuring signal corresponding to the strip pressure against the roll in the respective zone, and with a plurality of regulating zones comprising regulating devices for regulating the distribution of the strip tension, for example by means of readjustment of the distribution of the roll force along the roll gap, or by selective control of the temperature of the rolls across the width of the roll track, and a signal processing unit which is supplied with said measuring signals and is arranged to emit control signals to said regulating devices, is characterised in that at least one of the regulating zones has a width which covers at least one complete measuring zone and a fraction of one or two further measuring zones, and in that the signal processing unit is arranged to form, for theor each of said at least one regulating zones, a weighted sum of measuring from the or each measuring zone completely covered by the particular regulating zone and a fraction of the measuring signal from the or each measuring zone partial covered by the particular regulating zone, the or each fractional signal having a value corresponding to the degree of coverage of said measuring zone in relation to the particular regulating zone, and to generate from these sum signals a corresponding control signal for each regulating zone and supply it to the respective regulating device.

The invention will now be described, by way of example, with reference to the accompanying drawing, the single Figure of which is a diagram showing schematically how the measuring zones and regulating zones of a strip mill in accordance with the invention may be arranged relative to one another.

In the example illustrated, the bending roll 20 is equipped with sixteen measuring zones, which are numbered 1-16, of equal width. A number of regulating zones A-F are arranged in a known manner in the vicinity of the strip. Each regulating zone is provided with one (as in this case) or more than one nozzle, marked X, for applying a coolant onto the rolls (not shown) of the mill.

If a disturbance in the form of a change in the distribution of the strip tension occurs in one area, which is covered by regulating zone E, this is recorded as a change in the measuring signals from emasuring zones 11, 12, 13 and 14. Of these measuring zones, regulating zone E covers measuring zonesl2 and 13 entirely but only half of the measuring zone 11 and three-tenths of the measuring zone 14. The regulating signal, which is to be supplied to the regulating zone E from the signal processing unit 21, is then chosen according to the equation.

where noll designates a change of the signal from measuring zone 11, and so on.

Since the width of each measuring zone is constant and known, and since the width of each regulating zone is known in this case, the signal processing unit can be arranged so that it forms a weighted sum of the measuring signals from the whole measuring zones as well as fractions thereof corresponding to the width of each regulating zone; and, when a change in these measuring signals occurs, so that it forms a control signal to the regulating device commensurate with said change. In this way, the strip is continuously monitored with regard to changes occurring in the distribution of the strip tension, and the respective regulating devices are controlled to a corresponding degree.

As examples of other regulating devices may be mentioned the eccentric bearings in the supports of the two upper, intermediate backing rolls in strip mills of the Sendzimir type.

In an alternative arrangement (not shown), each regulating zone is provided with one or more nozzles for applying heat to the rolls of the mill. In another arrangement (also not shown), each regulating zone is provided with one or more sections for applying heat to the rolls of the mill by electrical heating, e.g. by electric heating lamps or inductively.

WHAT WE CLAIM IS: 1. A strip mill comprising a bending roll for measuring the variation of the strip tension across the strip width, said bending roll being divided into a plurality of measuring zones, each of which emits a measuring signal corresponding to the strip pressure against the roll in the respective zone, and with a plurality of regulating zones comprising regulating devices for regulating the distribution of the strip tension, and a signal processing unit which is supplied with said measuring signals and is arranged to emit control signals to said regulating devices, characterised in that at least one of the regulating zones has a width which covers at least one complete measuring zone and a fraction of one or two further measuring zones, and in that the signal processing unit is arranged to form, for the or each of said at least one regulating zones, a weighted sum of measuring signals from the or each measuring zone completely covered by the particular regulating zone and a fraction of the measuring signal from the or each measuring zone partially covered by the particular regulating zone, the or each fractional signal having a value corresponding to the degree of coverage of said measuring zone in relation to the particular regulating zone, and to generate from these sum signals a corresponding control signal for each regulating zone and supply it to the respective regulating device.

2. A strip mill according to claim 1, in which regulation of the distribution of the strip tension is effected by means of readjustment of the distribution of the roll force along the roll gap, or by selective control of the temperature of the rolls across the width of the roll track.

3. A strip mill according to claim 1 or 2, in which the regulating devices consist of a number of nozzles for applying a coolant onto the rolls of the mill, one or more cooling nozzles being put together to form a cooling zone.

4. A strip mill according to claim 1 or 2 and having working rolls backed by backing rolls and regulating devices for adjusting eccentric bearings in the supports of the two upper, intermediate backing rolls, which regulating devices are controlled by the control signals.

5. A strip mill according to claim 1 or 2 in which the regulating devices consist of a number of nozzles for applying heat to the rolls of the mill by way of flames, one or more nozzles being put together to form a heating zone.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. accompanying drawing, the single Figure of which is a diagram showing schematically how the measuring zones and regulating zones of a strip mill in accordance with the invention may be arranged relative to one another. In the example illustrated, the bending roll 20 is equipped with sixteen measuring zones, which are numbered 1-16, of equal width. A number of regulating zones A-F are arranged in a known manner in the vicinity of the strip. Each regulating zone is provided with one (as in this case) or more than one nozzle, marked X, for applying a coolant onto the rolls (not shown) of the mill. If a disturbance in the form of a change in the distribution of the strip tension occurs in one area, which is covered by regulating zone E, this is recorded as a change in the measuring signals from emasuring zones 11, 12, 13 and 14. Of these measuring zones, regulating zone E covers measuring zonesl2 and 13 entirely but only half of the measuring zone 11 and three-tenths of the measuring zone 14. The regulating signal, which is to be supplied to the regulating zone E from the signal processing unit 21, is then chosen according to the equation. where noll designates a change of the signal from measuring zone 11, and so on. Since the width of each measuring zone is constant and known, and since the width of each regulating zone is known in this case, the signal processing unit can be arranged so that it forms a weighted sum of the measuring signals from the whole measuring zones as well as fractions thereof corresponding to the width of each regulating zone; and, when a change in these measuring signals occurs, so that it forms a control signal to the regulating device commensurate with said change. In this way, the strip is continuously monitored with regard to changes occurring in the distribution of the strip tension, and the respective regulating devices are controlled to a corresponding degree. As examples of other regulating devices may be mentioned the eccentric bearings in the supports of the two upper, intermediate backing rolls in strip mills of the Sendzimir type. In an alternative arrangement (not shown), each regulating zone is provided with one or more nozzles for applying heat to the rolls of the mill. In another arrangement (also not shown), each regulating zone is provided with one or more sections for applying heat to the rolls of the mill by electrical heating, e.g. by electric heating lamps or inductively. WHAT WE CLAIM IS:

1. A strip mill comprising a bending roll for measuring the variation of the strip tension across the strip width, said bending roll being divided into a plurality of measuring zones, each of which emits a measuring signal corresponding to the strip pressure against the roll in the respective zone, and with a plurality of regulating zones comprising regulating devices for regulating the distribution of the strip tension, and a signal processing unit which is supplied with said measuring signals and is arranged to emit control signals to said regulating devices, characterised in that at least one of the regulating zones has a width which covers at least one complete measuring zone and a fraction of one or two further measuring zones, and in that the signal processing unit is arranged to form, for the or each of said at least one regulating zones, a weighted sum of measuring signals from the or each measuring zone completely covered by the particular regulating zone and a fraction of the measuring signal from the or each measuring zone partially covered by the particular regulating zone, the or each fractional signal having a value corresponding to the degree of coverage of said measuring zone in relation to the particular regulating zone, and to generate from these sum signals a corresponding control signal for each regulating zone and supply it to the respective regulating device.

6. A strip mill according to claim 1 or 2, in which the regulating devices consist of a

number of sections for applying heat to the rolls of the mill by electrical heating, one or more sections being put together to form a heating zone.

7. A strip mill according to claim 6, in which the electrical heating is effected by heating lamps or inductively.

8. A strip mill according to any of the preceding claims, in which the measuring zones of the bending roll are of equal width.

9. A strip mill according to claim 1, constructed and arranged substantially as herein described with reference to, and as illustrated in, accompanying drawing.