JPH0241490A - Control device of profile of paper thickness - Google Patents

Abstract

PURPOSE:To shorten settling time of profile by providing a means of treatment corresponding to position calculating deviation in each operating end and a means varying corresponding relationship of measured values of profile of paper thickness and plural actuators. CONSTITUTION:Plural actuators installed in a calendar roll are driven by operating output calculated according to deviation between measured values of profile of paper thickness in papermaking machine and setting value. Corresponding relationship between plural measured values of profile of paper thickness in paper width direction and plural actuators is decided and deviation with each operation end is calculated by the means of treatment corresponding to position 18. Corresponding relationship between measured value of paper thickness profile and plural actuators is varied by sequence means 23 according to indication C1 of operator or setting state C2 of profile of paper thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to improving the controllability of profile control in a paper thickness profile control process device of a paper machine.

(Conventional technology) An overview of the papermaking process will be explained with reference to FIG.

The raw material valve P joins the return raw material from the white water silo 3 through the seed box 11 and the seed inlet valve 2, and is supplied to the head box 5 by the pump 4. The raw material in the head box is discharged in the form of a sheet onto the wire part 8 from the gap in the slicing lip 6, is squeezed out in the press part 9, heated and dried with steam in the dry part 1o, and then transferred to the calender 11.
After that, it is wound onto a reel 12 and becomes a product. 7 is a plurality of (for example, 6) for manipulating the gap of the slice lip.
0 slice bolts.

13 is the basis weight of the paper by scanning the product in the paper width direction.

This is a B/M meter that measures paper thickness with a moisture content of 1. Based on this measurement value, each profile measurement value PV, PV2. PV3 is calculated by dividing the paper in the width direction into a plurality of points, for example, 360 points.

Profile measurement of absolute dry basis weight at each point determined by calculation gp
The difference between v and the setting @SV1 is controlled and calculated by the profile control leg device 14, and the lip opening degree is adjusted by operating the slice bolt 7 corresponding to the measurement point using the operation output M■1, and the absolute dry basis weight profile of the product is determined. Feedback control is performed so that the absolute dry basis weight matches the set absolute dry basis weight profile.

Similarly, the difference between the calculated moisture content profile measurement &1 PV2 and the set value S V 2 at each point is controlled and calculated by the profile control device 14, and realized by the infrared heater 01 corresponding to the measurement point using the operation output MV2. Feedback control is performed so that the moisture content profile matches the set profile by manipulating the output of the heater in the profile control device.

Similarly, the difference between the calculated paper thickness profile measurement @P3 at each point and the set value SV3 is determined by the profile control device 14.
The control calculation is performed using the operation output M V 3 to operate the operation end of the carenter corresponding to the measurement point to adjust the roll cap, and feedback control is performed so that the paper thickness profile of the product matches the set profile.

15 is a man-machine interface that communicates with the control device 14 and has a profile display function.

The present invention relates to improving paper thickness profile control among these three types of profile control.

FIG. 5 is a partially enlarged view of the calender roll 11, which is an actuator for controlling the paper thickness. The actuators 17, 172, 173, . . . are arranged facing the rolls.

There are various types of actuators, including a method in which electromagnetic waves are supplied to the roll using a coil and the relevant portion is expanded by heat generated by an eddy current, and a method in which hot air and cold air are generated by nozzles for expansion and contraction.

Figure 6 shows the correspondence between a plurality of paper thickness measurement points (for example, 360 points) n and a plurality of zones m that each actuator has. Mechanically allocate multiple measurement points to

In this example, three measurement points are attached to one zone. The relationship between zones and measurement points is as shown in the table below.The average value of the measured values in each zone is taken as the measured value in that zone, the deviation from the set profile is calculated, and the control calculation for that zone is calculated based on this deviation. is calculated.

FIG. 7 shows the functional block line section of the paper thickness profile control system, where 18 is the 4 correspondence and deviation processing function, and 1 is the speed type PI calculator for the deviation calculated for each zone.
, 20 is a non-interference algorithm processing function that compensates for interference between adjacent operation ends, 21 is an optimal paper edge output signal processing function that predicts and estimates the measured value of the paper edge and generates an apparent operation output, and 22 is a This is an output average value optimization processing function that performs bias processing on each operation output signal so that the average value of all operation outputs is constant.

(Problem to be solved by the invention) Is it possible to perform paper thickness profile control in a steady state with such a configuration?Recently, the number of actuators has increased (for example, 10
0 lines), so the width of one zone is becoming narrower.

For this reason, even if the amount of operation for one zone is changed, the change in paper thickness is small. As a result, there is a problem that the control gain is insufficient when starting to make paper or when starting after paper runs out, and it takes a long time to settle the profile.

An object of the present invention is to provide a filter paper thickness profile control device that can solve these problems by simple means.

(Means for Solving the Problems) The structural feature of the present invention is to operate a plurality of actuators attached to the calender roll as operating ends based on the deviation between the paper thickness profile measurement value and the set value of the paper machine. ,
In an apparatus for controlling a paper thickness profile using a roll cap, a position correspondence processing means for determining the correspondence between the plurality of paper thickness profile measurement values in the paper width direction and the plurality of actuators and calculating a deviation for each operating end, and an operator; The present invention further comprises a sequence means for changing the correspondence between the paper thickness profile measurement value and the plurality of actuators in accordance with the instruction or the settling state of the paper thickness profile.

(Function) A plurality of actuators attached to the calender roll are driven by an operation output calculated based on a deviation between a paper thickness profile measurement value of the paper machine and a set value.

The position correspondence processing means determines the correspondence between the plurality of paper thickness profile measurements in the paper width direction and the plurality of actuators, and calculates the deviation for each operating end.

The sequence means changes the correspondence between the paper Jj profile measurement value and the plurality of actuators in accordance with an operator's instruction or a settled state of the paper thickness profile.

(Example) The present invention will be described in detail based on the functional block diagram of FIG. Elements that are the same as those described in FIG. 7 are designated by the same reference numerals, and their explanation will be omitted, and a description of the features of the present invention will be added.

Reference numeral 23 denotes a sequence means, which changes the correspondence relationship between the profile measurement point and the actuator in response to a command Y to the position correspondence processing function 18. It is activated by the manual operation C1 of the commanding operator or by the signal C2 from the profile monitoring means 24.

That is, when the profile is not stable (the deviation is large) and the control gain is insufficient, the positional relationship is changed manually or automatically.

An example of changing the correspondence relationship is shown in the table below.

That is, the actuators in adjacent zones are simultaneously operated by operating outputs based on deviations from groups of the same measurement points. Although the control resolution is reduced by such an operation method, it is possible to increase the control gain.

FIG. 2 is a flowchart showing a signal processing procedure to explain the present invention in detail. When the profile is stable, control calculations with high resolution are performed using the same positional relationships as in the past, not shown in Table 3. If the profile is not stable, the control calculation is changed to the correspondence according to table 2, and the control gain is increased.

Figure 3 shows a comparison of the control amount with conventional control based on this change in correspondence, and compares it with the amount of change in paper thickness in the case of conventional independent control for each zone shown in (A). It can be seen that the amount of change in paper thickness increases significantly when adjacent zones are operated simultaneously as shown in (B).

In the above embodiment, the simultaneous operation of adjacent zones has been described, but it is also possible to operate two or more zones at the same time.

Furthermore, the inputs to the sequence means include, in addition to the inputs of the embodiments,
It is possible to input factors that require the control gain to be increased transiently, such as when two sheets are out at the start.

Also, the diple that defines the correspondence is man-machine means 1
5, it is easy to make maintenance possible, and it is possible to realize a paper thickness profile control device that is versatile and compatible with different brands.

(Effects of the Invention) As explained above, according to the present invention, when the paper thickness profile is not stable (when the deviation is large), it is possible to perform an operation that obtains a large control gain even though the resolution in the width direction is not good. This makes it possible to shorten profile settling time. Therefore, it is possible to perform an operation in which the occurrence of paper waste can be reduced, and it is possible to contribute to improving the controllability of paper thickness profile control in a paper machine.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a flowchart showing a signal processing procedure for explaining the operation,
Fig. 3 is a characteristic diagram for comparing control amounts with a conventional control device, Fig. 4 is a conceptual diagram of a paper machine control device, Fig. 5 is a configuration diagram of an actuator section for paper thickness profile control, and Fig. 4 is a conceptual diagram of a paper machine control device. FIG. 6 is an explanatory diagram showing the correspondence between measurement points and actuator zones, and FIG. 7 is a functional block diagram showing an example of a conventional paper thickness control system. 18...Position corresponding processing function 19...Velocity type PI
Arithmetic function 20...Interference algorithm processing function 21
... Optimal paper edge output signal processing function 22 ... Output average value optimization processing function 23 ... Sequence means 24
...Profile monitoring means

Claims (1)

[Claims] A device that controls the paper thickness profile using a roll cap by operating multiple actuators attached to the calender roll as operating ends based on the deviation between the paper thickness profile measurement value and the set value of the paper machine. position correspondence processing means for determining the correspondence between the paper thickness profile measurement value and the plurality of actuators and calculating the deviation for each operating end; A paper thickness profile control device comprising a sequence means for changing a value and a correspondence relationship between the plurality of actuators.