JP2874314B2 - Profile control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a profile control device for controlling a weight per unit area (hereinafter referred to as "weighing") of a paper machine, a coating machine, a film machine or the like to a target value. In particular, the present invention relates to improvement of controllability when paper runs out.

<Prior Art> A profile control device is disclosed, for example, in Japanese Patent Application Laid-Open No. 63-75195 proposed by the present applicant. FIG. 11 is a block diagram showing a configuration of a conventional paper machine and a control device thereof disclosed in the above publications. In the figure, a head box HB contains a raw material and is discharged from a plurality of slices arranged in the width direction. The opening degree of the slice is controlled by the actuator ACT, and an amount of the raw material corresponding to the opening degree is squeezed when passing through the wire part WP, and dried when passing through the dryer DR to a predetermined moisture content. Becomes In the calendar CL, the dried paper is compressed to a predetermined paper thickness (calipers), and wound on a reel RL. The white water from the water squeezing of the wire part WP is received at the pit PT and returned to the head box HB by the fan pump PMP.

The grammage, moisture content and paper thickness are
Each is measured by the sensor BM and sent to the profile detection unit 10. The profile detection unit 10 is also in charge of the pre-processing calculation for controlling the basis weight, moisture content, and paper thickness profile as follows.

(I) The required seed flow rate is calculated from the deviation between the target value of the grammage and the measured value.

(Ii) Calculate the variation in weighing in the width direction.

(Iii) Calculate a steam temperature (flow rate) having energy for providing a required degree of dryness from a deviation between the target value and the measured value of the moisture content.

(Iv) In order to reduce the variation in paper thickness,
Is controlled locally. This control is performed by heating / cooling the calendar roll. For example, heating uses steam,
Cooling is performed by blowing air. The seed opening valve control unit 20 calculates the valve opening based on the seed flow rate sent from the profile detection unit 10, gives the calculated opening to the seed opening valve VLV, and controls the average basis weight in the paper width direction to a set value. The slice control unit 30 calculates the amount of operation of each actuator ACT, controls the amount of the discharged raw material of each slice, suppresses variations in the basis weight in the width direction, and achieves uniform quality. The steam controller 40 is the profile controller 10
The steam pressure is determined based on the steam flow indication value sent from the plant and given to the steam valve STV to control the moisture content to the set value. The calendar control unit 50 heats / cools a predetermined position in the paper width direction of the calendar CL to a predetermined diameter to obtain a required paper thickness.

In such an apparatus, if a disturbance occurs in the process, a deviation occurs between the target value and the actual measurement value, resulting in insufficient drying and paper breakage. In the conventional paper out control, an output pattern for a slice at the time of paper out is output when paper out occurs, and the output value is changed from the pattern at the time of paper passing to converge to a desired paper quality. In this case, it is good paper out control to minimize the waste paper.

<Problems to be Solved by the Invention> However, in recent years, with the diversification of actuators, there have been cases in which the above control cannot cope. For example, if an actuator ACT that retracts when paper runs out is used, even if the output pattern is changed when paper runs out, it will not be output from the actuator ACT, and the settling time after passing the paper will be longer, and the caliper profile will be lower. There is a model that has a problem of deviating from the above and increasing waste paper. Also, depending on the installation location of the dryer DR,
It is known that even when the paper is out of paper, the paper is inside, and if only the pattern at a specific position is changed, a predetermined moisture content can be obtained, and the waste paper can be almost eliminated.

The present invention has solved such a problem, and provides a profile control device that can be generally used for various actuators and a dryer DR installation location, and that has a reduced settling time after paper passing and has less waste paper. With the goal.

<Means for Solving the Problems> FIG. 1 is a configuration block diagram for explaining the present invention that achieves the above object. In the figure, a detection end 10 measures the basis weight, moisture content, thickness, and the like in the width direction. The profile control device 20 inputs the signal measured at the detection end 10,
An operation amount output pattern in a direction of reducing the deviation by comparing the profile detection amount with the target value is output to the operation terminal 30. The operation end 30 is provided to be distributed in the width direction of a paper machine, a coating machine, a film machine, or the like, and adjusts values such as basis weight, moisture content, and thickness.

The pattern storage unit 40 immediately before a paper break stores an output pattern of the operation terminal 30 when a paper break occurs in the paper machine or the like. The paper-out-of-paper pattern storage unit 50 stores a predetermined output pattern of the operation terminal 30 when a paper out occurs. The pattern switching unit 60 outputs the output pattern of the out-of-paper pattern storage unit 40 to each operation terminal when a paper break occurs, and then controls the output pattern of the pattern storage unit 50 immediately before the paper break when each paper feed is started. Output to the end.

<Operation> Each component of the present invention performs the following operation. The out-of-paper pattern storage unit 40 holds an output pattern of the operation terminal 30 when a paper break occurs when the process is in an equilibrium state. The out-of-paper-pattern storage unit 50 stores a pattern that can be output when the paper runs out, which is known empirically. The pattern switching unit 60 selects the out-of-paper pattern storage unit 50 during the out of paper, and selects the pattern storage unit 40 immediately before the out of paper after the paper is passed,
An output pattern for the operation terminal 30 of the profile control device 20 is assumed. After the sheet is passed, the output pattern in the state of reaching the equilibrium state is obtained from the pattern storage unit 40 immediately before the paper breakage, so that the predetermined paper quality is earlier than when control is started from the output pattern of the pattern storage unit 50 at the time of paper breakage. Is obtained.

<Example> Hereinafter, the present invention will be described with reference to the drawings.

FIG. 2 is a configuration block diagram showing one embodiment of the present invention. In the figure, the detection end 10 measures the grammage, moisture content, thickness, etc. in the width direction. For example, for the grammage, refer to the β-ray thickness gauge (see Yokogawa Technical Report Vol.26p.179 (1982)). ) And moisture content are measured by infrared moisture meter (Yokogawa Technical Report Vol.24p.107 (198
0)) and an air levitation caliper meter (see the same document) for the thickness. In relation to measurement in the width direction, the detection end 10 is supported by a housing called a frame, and performs measurement while scanning in the paper width direction. The profile control device 20 inputs the signal measured at the detection end 10,
The operation amount output pattern in the direction of reducing the deviation by comparing the profile detection amount with the target value is output to the operation end 30. The operation end 30 is provided in a paper machine, a coating machine, a film machine, and the like, and corresponds to the above-described actuator for adjusting the basis weight, a dryer for adjusting the water content, a calendar for adjusting the thickness, and the like. Are also provided in the paper width direction, and the operation amount of each operation end 30 can be determined independently.

The pattern storage unit 40 immediately before the paper break stores the output pattern of the operation terminal 30 when the paper break occurs in the paper machine or the like.
And reads the pattern output to the operation terminal 30. The out-of-paper pattern storage unit 52 holds a predetermined output pattern of the operation terminal 30 when the out-of-paper condition occurs. This output pattern is adapted to the out-of-paper condition of the target process, and is usually determined by experience. The out-of-paper pattern unit 54 loads the contents of the out-of-paper pattern storage unit 52 for the specific operation end 30, and loads the contents of the out-of-paper pattern unit 54 for the remaining operation ends 30 and stores them as output patterns. The pattern switching unit 60 intervenes with respect to the output pattern of the profile control device 20 when a paper break occurs, and outputs an output pattern of the paper break pattern unit 54 to each operation terminal 30 when a paper break occurs,
Then, when paper passing starts, the pattern storage unit just before
Forty output patterns are output to each operation terminal 30. The timer 70 delays the switching operation of the pattern switching unit 60. Since the operation of the actuator may require a large time constant, the timer 70 is provided to stabilize the controllability. The value of the timer may be about a time constant, and may be set to a value different from n seconds when the paper runs out and m seconds when the paper feed starts. When the time constant is small, the timer 70 may not be provided.

FIG. 3 is an explanatory diagram of an output pattern, in which the operation amounts of the operation end 30 of the pattern storage unit 40 immediately before the paper break, the pattern storage unit 52 at the time of paper break, and the paper break pattern unit 54 are arranged in the paper width direction. In the figure, an area A and an area C are provided at the edge of the paper, and an area B is set at the center. Paper cut pattern section
Numeral 54 loads data from the pattern storage unit 52 when the paper runs out for both ends A and C, and loads data from the pattern storage unit 40 immediately before the paper run for the center B. The reason that the content of the pattern storage unit 52 when the paper runs out is determined only for both ends A and B,
For the following reasons. For a process in which paper is present inside the dryer while the paper is running out, there is an empirical thing called fine paper (horizon). Both ends of the paper are set to a predetermined value because the calendar or the like cools quickly, and the center is blanked on the assumption that the paper is read from the pattern storage unit 40 immediately before the paper breaks.

FIG. 4 is a time chart showing the relationship between the output pattern and the process. During paper passing, the profile is controlled by the profile controller 20 or the pattern storage
There are 40 output patterns. During the paper break, the output pattern of the paper break pattern section 54 is in principle.
In the case where a timer is provided, the pattern storage unit 40 immediately after the occurrence of the paper-out occurs instead of the paper-out pattern unit 54 from the pattern storage unit 40 immediately before the paper-out, and the pattern-out immediately before the paper-out unit 54 Replaces part 40.

Fig. 5 is a time chart showing the transition of data.
(A) is a paper out signal, (B) is a pattern just before paper out,
(C) is a paper break pattern, (D) is a pattern switching signal,
(E) is an n-second timer, (F) is a pattern switching pulse,
(G) is an m-second timer, (F) is a pattern switching pulse,
(H) is an output pattern. At time T1, the paper-out signal indicating occurrence of paper-out becomes H. Then, the output pattern at time T1 of the profile control device 20 is loaded into the pattern storage unit 40 immediately before the paper break. Time this load completed
At T2, data is loaded into the out-of-paper pattern unit 54 from the immediately before out-of-paper pattern storage unit 40 and the out-of-paper pattern storage unit 52, and at time T3, the pattern switching unit 60 instructs switching. Then, the n-second timer starts measuring time, and the time is up at time T4, a pattern switching pulse is output, and the output pattern of the profile control device 20 becomes the content of the paper cut pattern unit 54. Next, when paper feeding is resumed at time T5, the m-second timer starts measuring time, and the time-up is performed at time T6.
At T7, a pattern switching pulse is output, and the output pattern of the profile control device 20 becomes the content of the pattern storage unit 40 immediately before the paper break.

Next, a case where the present invention is applied to preheating of a calendar will be described. 6A and 6B are explanatory views of the calendar and the actuator, wherein FIG. 6A is a front view and FIG. 6B is a side view. Paper that has passed through a dryer (not shown) is wound on a reel via a calendar. FIG. 7 is an explanatory view of a profile control state, in which (A) is a paper thickness profile, (B) is a control output to an actuator, and (C) is a calendar temperature pattern. The actuator controls the local temperature by blowing steam or air to the calendar, and adjusts the diameter of the calendar using thermal expansion.

In such an apparatus, when a paper break occurs, the actuator retracts to the position shown by the broken line in the figure. FIG. 8 is an explanatory diagram of the calendar temperature pattern, in which the broken line shows the state before the paper break, and the solid line shows the state after the paper break. Since the actuator is separated and the amount of heat brought in from the dryer carrying the paper disappears, the calendar cools rapidly.

9A and 9B are explanatory diagrams of the output pattern. FIG. 9A shows a pattern storage unit 52 when paper is out of paper, and FIG.
Reference numerals 40 and (C) denote actuator output patterns of the paper cut pattern portion 54. In the out-of-paper pattern storage unit 52, a larger operation amount is set in advance for an actuator having a large output in a steady state. Then, when an actuator arrival signal (an instruction from the operator or an instruction from a higher-level control device, which indicates that the actuator is forcibly attached to the calendar even while the paper is running out) is received while the paper is running out, The output of FIG. 9C is performed. Then the calendar is warmed.

FIG. 10 is an explanatory diagram of the temperature pattern of the calendar by the actuator landing signal. The solid line is the temperature pattern by the actuator output, and the broken line is the temperature pattern when the actuator is out of paper. Even after the actuator arrival signal is sent, the paper is still out of paper. Therefore, the papermaking paper system automatically removes the actuator from the calendar after a certain period of time. Then the calendar starts to cool down again, but by the time the paper is connected, it approaches the temperature pattern before the paper break. Therefore, the calendar temperature patterns after the paper passing and before the paper break are close. When a predetermined time m seconds elapses after the paper is passed, the pattern switching unit 40
, The paper thickness profile control can be continued without breaking the calendar temperature pattern.

In this way, the change in the temperature pattern of the calendar is reduced before and after the paper breakage, which is a large disturbance in the control of the paper thickness profile, so that the variation in the thermal expansion of the calendar is reduced. This has the effect that the controllability of the paper thickness profile is significantly improved.

<Effects of the Invention> As described above, the present invention has the following practical effects.

When a paper break occurs, the output pattern of the paper break pattern storage unit 50 is provided during the paper break, and the output pattern of the pattern storage unit 40 immediately before the paper break is provided to the operation end after the paper has passed.
Therefore, since the output pattern suitable for the out-of-paper state is given earlier from the output pattern in the equilibrium state, early stabilization of the process can be realized. Thus, waste paper is reduced.

When part of the contents of the paper break pattern section 54 is obtained from the pattern storage section 52 at the time of paper break and the rest is obtained from the pattern storage section 40 immediately before the paper break, early stabilization is realized in the case where thin paper occurs. .

When a timer is interposed in the switching of the pattern switching unit 60 as in the embodiment, the time constant of the actuator is compensated, and the control becomes stable.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram illustrating the present invention. FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 3 is an explanatory diagram of an output pattern, FIG. 4 is a time chart showing the relationship between an output pattern and a process, and FIG. It is a time chart shown. 6 is an explanatory diagram of a calendar and an actuator, FIG. 7 is an explanatory diagram of a profile control state, FIG. 8 is an explanatory diagram of a calendar temperature pattern, FIG. 9 is an explanatory diagram of an output pattern,
FIG. 10 is an explanatory diagram of a calendar temperature pattern based on an actuator landing signal. FIG. 11 is a configuration block diagram of a conventional process. 10: detection end, 20: profile control device, 30: operation end, 40: pattern storage unit just before paper break, 50, 52 ... pattern storage unit when paper breaks, 54: paper break pattern unit, 60 ...
... Pattern switching unit.

Claims (3)

(57) [Claims] 1. A signal obtained by measuring a basis weight, a moisture content, a thickness, etc. in a width direction is input, and an amount of operation in a direction to reduce a deviation by comparing the detected amount of the profile with a target value is set in a paper machine or a coating machine. Machine,
In a profile control device that outputs to operation terminals distributed in the width direction provided in a film machine or the like, a pattern storage unit immediately before a paper break that holds an output pattern of the operation terminal when a paper break occurs in the paper machine or the like, A paper break pattern storage unit that holds the output pattern of the operation terminal when a predetermined paper break occurs, and an output pattern of the paper break pattern storage unit that outputs the paper break pattern is output to each operation terminal when a paper break occurs, and then the paper feed starts. A pattern switching unit that outputs an output pattern of the pattern storage unit immediately before the paper breakage to each operation terminal when the operation is performed. 2. A signal obtained by measuring the basis weight, moisture content, thickness, etc. in the width direction is input, and the amount of operation in the direction of reducing the deviation by comparing the detected amount of the profile with a target value is set in a paper machine, Machine,
In a profile control device that outputs to operation terminals distributed in the width direction provided in a film machine or the like, a pattern storage unit immediately before a paper break that holds an output pattern of the operation terminal when a paper break occurs in the paper machine or the like, A paper-out-time pattern storage unit that holds an output pattern of the operation end when a predetermined paper-out occurs, and a content of the paper-out-time pattern storage unit for a specific operation end among the operation ends distributed in the width direction, For the remaining operation ends, the paper break pattern section that loads the contents of the pattern storage section immediately before the paper break and the output pattern of the paper break pattern storage section when a paper break occurs are output to each operation end, and then when paper feeding is started And a pattern switching unit that outputs an output pattern of the pattern storage unit immediately before the paper breakage to each operation terminal. Iru control device. 3. A signal obtained by measuring a paper thickness in the width direction is input, and an operation amount in a direction of reducing the deviation by comparing the detected amount of the paper thickness profile with a target value is distributed in the width direction. A profile control device for outputting an actuator for blowing steam or air to a calendar to be compressed; When the paper runs out, the pattern storage unit holds the output pattern of the actuator at the time, and among the actuators distributed in the width direction, the contents of the paper breakage pattern storage unit are loaded for the actuator in the end region of the paper, and the remaining actuators are loaded. A paper break pattern section that loads the contents of the pattern storage section immediately before a paper break A pattern switching unit that outputs an output pattern of the paper break pattern storage unit to each actuator when this occurs, and outputs an output pattern of the pattern storage unit immediately before paper break to each actuator when paper feeding is started thereafter. A profile control device, comprising: