DE19722523A1 - Method and device for hydraulic-electrical gap control - Google Patents

Abstract

The invention relates to a method and device for regulating the width (h) of the gap between at least two rollers coupled in a roll mill. If the gap changes as a result of disturbances during the rolling process, the piston travel and the valve position are detected and corrected so that the gap returns to the predetermined width. The operator can modify this predetermined width during operation. The device for implementing this method is characterized in that a valve (10) is fitted on a roller (1) having one control loop for the valve (10), and one for the roller (1).

Description

The invention relates to a method and a device for hydraulic-electrical Regulation of the nip in rolling mills, especially in multi-rolling mills Processing of liquid to highly pasty colors and other media.

In the applicant's earlier DE 30 16 785, a hydraulic multi-roll mill is included two or more rollers, their end bearings by a hydraulic piston-cylinder connection order are interconnected, disclosed. By applying hydraulic pressure to the clamping or releasing chamber of the hydraulic piston-cylinder arrangement the rollers towards or away from each other with a clamping or releasing force acted upon, by presetting the maximum pressure in the clamp a minimum gap width is permanently preset. The fluctuations in the gap Width in operation by adjusting a pressure reducing valve for the loosening chambers reduced or enlarged accordingly. This pressure reducing valve will controlled by a nip encoder.

Another DE 30 16 786 from the applicant describes a method and a device to regulate the gap width between two in a multi-roll mill tendency rolls described. The setting of the nip is based on follow the principle. If the gap width changes during the rolling process the cooling or heating intensity is first maintained while maintaining the roller pressure changed the sense that the gap resumes the predetermined width, and that if the range of variation of the cooling or heating intensity is insufficient, the Roller pressure to produce or restore the predetermined gap width, as is changed in the above-mentioned DE 30 16 785.

Each of the rollers has its own control system or regulator. The controller of the first The roller becomes an actual signal via a temperature sensor of the roller and a target signal supplied via a setpoint device.  

A temperature control signal thus arises at the output of the controller a spool is created. Another temperature signal from the controller is applied to a differential temperature setting stage and one at the output of this The signal generated in the stage provides a target temperature signal for the second roller. This The signal is fed to the controller of the second roller. An output signal from this Controller is fed to another control spool analogous to the first spool, which covers the cross section of the water pipe so that the temperature of the Roller is adjusted to a predetermined target value. A disadvantage of this be Known device are cooling or heating water pipes, one for each roller Cooling or hot water pipe is provided. Another disadvantage is the transition from the first cooling or heating variation area to the second variation area where with the roller pressure and its changes to change the gap width ge will work.

Practice shows that the minimum gap width before production starts Lich mechanically, e.g. B. is set with gears. The gap fluctuations, wel caused by the viscosity changes of the processing product after completion of production d. H. newly hired outside of the company the.

The object of the present invention is the desired gap width between at least two rolls operating in a multi-roll mill in operation to restore or make reproducible. If the gap fluctuates This does not become wide as a result of disturbance variables, as in the known solutions except half of the operation or set in operation, but those for a specific product Abberu given parameters for setting the fluctuating gap width be opened.

This object is achieved with the features of claim 1. The new procedure ren is characterized in that the piston travel in the hydraulic piston-cylinder-An order and the valve setting during the rolling process detected and correct be greed so that the gap assumes the predetermined width again. The past  correct gap width is in a comparator at the input of the first control loop fed. Positions of the piston S are also fed in. A first way knife detects the piston position during the entire rolling process and delivers corresponding actual signals to the first controller, which has an actuating signal determined a new setting of the piston. According to the new procedure, in addition the piston position also recorded and corrected the valve position. This is with the second control loop solved. Another odometer registers the valve position and sends actual signals to a second controller. In a comparator at the entrance of the second control circuit is the setting signal for the valve with the actual signal for the Valve compared and given to the second controller so that at the output of the second control a control signal for the valve. So that the valve and accordingly, the cylinder re-regulated. This process has several advantages compared to the earlier application by the applicant of DE 30 16 786. To an ent falls the first stage of the known method, namely the adjustment of the gap width with the help of the cooling or heating intensity including complicated and costly cooling or heating water pipes, in addition there are also several pressure reducing valves and the back pressure reducing valve for the second setting variant with the roller pressure. The outstanding advantage arises from the fact that the new method the gap can be freely selected during the rolling process and the setpoint is regulated becomes.

The invention further relates to a new device for carrying out the method. The device has a valve, which on the hydraulic piston-cylinder arrangement is arranged on. Two coupled control loops record and correct the col way of the cylinder and the valve position. A P controller is preferred for the Control loop for the cylinder and a PID controller for the second control loop for the Valve. This device is particularly suitable for use in rolling mills.

The invention is described below with reference to the drawings; in this shows

Fig. 1 is a schematic representation of a two-roll mill in front view and

Fig. 2 is a schematic representation in the manner of a block diagram of the control loops according to the invention.

In Fig. 1, two parallel to each other and a roll gap h forming roll 6 , 7 are shown, which are held by a hydraulic piston-cylinder arrangement at a predetermined more or less short distance. Each pair of rollers is provided with a piston-cylinder arrangement on both sides of the end face. A valve 10 , which restores the initial setting of the cylinder 1 , is arranged in each piston-cylinder arrangement.

According to Fig. 2 registers a displacement measuring device 2 the piston travel during the Walzenvor loss and sends an actual signal x _i to a comparator 3 which is connected to the input of a first regulator 4. In the comparator 3 , the setpoints x _s for the piston travel are specified from the outside, for. B. from a controller 5 , and fed. The comparator 3 outputs a difference signal x _w from signals x _i and x _s to the first controller 4 , which outputs an actuating signal x _st to a further comparator 8 . A second odometer 11 supplies the valve position y _i to the second comparator 8 . This outputs a difference signal y _w from the signals y _i and x _st to a further controller 9 , which outputs an actuating signal y _st to the valve 10 . In this way, the predetermined roll gap h or its changes during the rolling process are corrected, so that optimal quality of the product is guaranteed. When using the coupled control loops according to the invention, the back pressure reducing valves used in earlier solutions cited above are also eliminated. Further cost savings result from the fact that the pressure reducing valves for the clamping chambers of the piston-cylinder arrangement are also eliminated. The first adjustment or the restoration of the roller pressure in the clamping and releasing chambers of the piston-cylinder arrangement is carried out with the aid of a single valve, ie a coupled control circuit shown in FIG. 2 is provided for each piston-cylinder arrangement.

Reference list

1

cylinder

2nd

first odometer
x _i

Controlled variable (piston travel)

3rd

first comparator
x _p

Setpoint for the piston stroke (specified from outside)
x _w

Control deviation (x _f

= X _i

-X _p

)

4th

first controller (P controller)
x _st

Actuating variable for the piston stroke

5

control

6

,

7

Rollers

8th

further comparator

9

second controller (PID controller)

10th

Valve

11

second odometer
y _i

Control variable (valve position)
y _s

Setpoint for valve position
y _w

Control deviation
h nip width

Claims (11)

1. A method for matching the gap to the product during the rolling process between at least two rollers working together in a rolling mill, which can be mutually clamped or detached from one another by hydraulic piston-cylinder arrangements provided on the roller end faces, with a predetermined product adapted to the product Roll pressure and roll zenspalt is set, characterized in that when changing the gap h during the rolling process, the piston travel and the valve position are detected and corrected so that the gap assumes the predetermined width. 2. The method according to claim 1, characterized in that the nip (h) is detected and set using two control loops. 3. The method according to claim 2, characterized in that the first Re gelkreis the piston travel and the second control loop detects the valve position and a poses. 4. The method according to any one of claims 2 or 3, characterized in that the control loops are coupled. 5. Use of the method according to one of the preceding claims in a hydraulic rolling mill. 6. Device for carrying out the method according to one of the preceding claims, characterized in that a valve ( 10 ) is arranged on the cylinder ( 1 ) and that the valve ( 10 ) and the cylinder ( 1 ) are each assigned a control loop. 7. The device according to claim 6, characterized in that the first re gelkreis for the cylinder ( 1 ), the cylinder ( 1 ) itself, a distance meter ( 2 ), a most controller ( 4 ), a second controller ( 9 ) and a valve ( 10 ). 8. The device according to claim 7, characterized in that the second Re gelkreis for the valve ( 10 ), the valve ( 10 ) itself, a second odometer ( 11 ), and the second controller ( 9 ). 9. The device according to claim 7, characterized in that the first Controller is preferably a P controller. 10. The device according to claim 7 or 8, characterized in that the second controller is preferably a PID controller. 11. The device according to one of claims 6 to 10, characterized by Ver application in a hydraulic rolling mill.