JPH01270963A - Coating control apparatus - Google Patents

Abstract

PURPOSE:To reduce the labor of an operator by calculating the required alteration quantity of steam pressure when the brand of paper to be made is altered and applying said alteration quantity to a feedback control part to perform feedforward control. CONSTITUTION:A feedback control part 14, wherein the moisture content of the paper in the dryer part 6 being the post-stage of a coating apparatus is compared with objective moisture content and the feedback control of drying steam pressure is performed on the basis of the deviation between them, is provided. In a feedforward control part 13, the required alteration quantity of steam pressure is calculated from the change of the aforementioned various control quantities when the brand of paper to be prepared is altered and this steam pressure altered quantity is applied to the control quantity from the feedback control part 14. As a result, the setting of steam pressure necessary for reducing moisture content to the objective value of the new brand paper within a short time can be automatically performed and the labor of an operator can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a coating control device that improves followability to target value changes in paper machines and coating machines.

(Prior Art) FIG. 6 shows a schematic configuration of a coating bar and a dryer part corresponding to the latter stage of the coating process. The paper web 1 being manufactured is passed through a coating bart 2, where it is coated with a coating agent 4 stored in a tank 3. The portion of the coating agent 4 that does not adhere to the paper web 1 is collected in a recovery tank 5, transferred to the tank 3 again, and used again for coating.

The paper web 1 coated with the coating agent 4 in the coating bar 2 is passed through a dryer part 6, dried by a cylinder roll 7 heated by high-temperature steam, and then passed through a reeler 9.
It is being wound up.

In such a coating IV apparatus, moisture and other sensors 10 and 11 are arranged in the coating bar 2 and the dryer part 6, and the components of the paper web 1 (for example, the weight per unit area,
Control is performed so that paper having a target moisture content can be obtained by measuring the moisture content (water content, etc.) and optimizing the vapor pressure in the dryer part 6.

(Problem to be Solved by the Invention) However, in such a conventional coating control device, feedback control mainly based on PI control is performed in order to perform constant value control, and the vapor pressure in the dryer part 6 is feedback-controlled. As a result, the moisture content of paper web 1 is υl1fl adjusted to match the target value, so when the control target value is changed significantly, such as when changing the brand of paper to be manufactured, the control value is tracked to the target value. It takes time to do so. Therefore, the operator manually adjusts the steam pressure to a predetermined value to compensate for the time delay, which imposes a large amount of effort on the operator.

This invention was made in view of these conventional problems, and its purpose is to maintain the steam pressure even if there is a significant change in the control target value, such as a change in the brand of paper being manufactured. Feedforward control can automatically set the optimum moisture content for the newly changed paper brand to dry it in a short time, reducing operator effort. The purpose of the present invention is to provide a coating control device that can perform the following steps.

[Structure of the Invention] (Means for Solving the Problems) The coating control device of the present invention compares the moisture content of filter paper with a target moisture content in a dryer part, and supplies drying steam based on the deviation. Feedback i1 for pressure feedback control. In a coating control device equipped with a lJ flit section, when the brand of paper to be manufactured is changed, the required amount of change in steam pressure is determined from changes in various υ control amounts, and the required amount of change in steam pressure is calculated from the feedback control section of the dryer part. The present invention is characterized in that a feedforward control unit is provided to apply this vapor pressure change port to the control unit.

(Function) In the coating device of the present invention, when the brand of paper to be manufactured is changed, various hams are changed depending on the target paper brand, and the changes in these various control amounts Calculates the amount of change in steam pressure required to obtain a predetermined moisture content, and applies it to the feedback control mm of the dryer part to perform feedforward control to obtain the optimum steam pressure to obtain paper with the desired moisture content. You can move quickly.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

The mechanical configuration of the coating control device according to one embodiment of the present invention is as follows:
This is almost the same as FIG. 6 shown in the conventional example, and the detailed explanation of the structure is omitted by using the same reference numerals as in FIG. 6.

FIG. 1 is a block diagram of an embodiment of the present invention, which is comprised of a parameter calculation section 12, a feedforward control section 13, and a feedback control section 14.

Now, if we consider the plant model of dryer part 6 shown in Figure 2, the water that evaporates! The following model is established between iEa and the vapor pressure pa of the dryer part 6.

Ea=ni・pa (1) Therefore, in the parameter development section 12, the coating agent attachment 11
The parameters are constantly adjusted according to the fluctuations in 1a and are supplied to the feedforward control section 13. The feedforward control unit 13 controls the target water content l when the brand of paper to be manufactured is changed.
When the amount of moisture is changed significantly, the feedforward amount δPa calculated using the above parameters is applied to the feedback control tIl amount of the feedback control unit 14, and the steam of the dryer part 6 is adjusted so that the target moisture content can be obtained in a short time. Set the pressure.

In FIG. 3, the level of the coating agent 4 in the tank 3 is controlled by a level control section 16 to be constant. Here, when the coating agent is not newly replenished from the inlet 17, the recovery tank 5
The decrease of 1 novel can be thought of as a spear attached to 1 paper. Therefore, the adhesion amount g is determined from FIGS. 3 and 4 using the following formula.

g-α(VB-VA)/TXWXv +++++++
(2) Here, ■A: Tank level at the end of measurement ■B
: Tank level T at the start of measurement: Measurement time W: Paper width ■= Line speed α: Deposit amount conversion coefficient, which is information obtained from the sensors 15 and 18.

Furthermore, considering the balance formula for the amount of water in the dryer part 6, the amount of evaporated water Ea is given as follows.

Ea −(ul +μC−μ2)XWxv ・−・−(
3) However, μm: Moisture m before the coating bart μC: Moisture amount deposited on the coating bart μ2: Moisture content after the dryer part And here, the adhering moisture content μC is μc − (10O−C)xa /100...(
4).

However, C is the concentration (%) of the coating agent.

Therefore, from the above equations (1) and (3), the following equation is obtained.

= (μm+μC-μ2)xWxv/Pa...
(5) This parameter is calculated for each brand of paper to be manufactured and stored in the parameter calculation unit 12. Also,
By taking the average of the parameters that have been constantly calculated during actual plant operation, these parameters can be constantly rewritten to optimal conditions.

Now, when the brand of paper stock 1 is changed, various control amounts are changed. As a result of this, the sensor 10 obtains (
5) The values of the moisture content μm and the line speed V in the formula change, and due to this change, the moisture content μ2 of the final product obtained by the sensor 11 in FIG. 6 changes.

Therefore, in order to predict this fluctuation and make the water content μ2 quickly follow the target water content, feedback ill m [
1 is applied with a feedforward amount δPa shown by the following equation (7).

In other words, in equation (3), if changes in water content μm and line speed V are considered as disturbances in dryer part 6, μm→μm+δμm ・・・・・・(6) V−+
V+δV, and the feedforward I control amount δPa is δPa
1lll (μm+μC-μ2)XWXδV/+WXV
It is determined as xδμm/ (7).

Therefore, by applying this feedforward control δpa to the output of the feedback control section 14,
By controlling large fluctuations in the water content μ2 using the forward-forward control and performing feedback control in the feedback control section 14, it is possible to quickly respond to changes in the brand of paper being manufactured.

[Effects of the Invention] As described above, according to the present invention, the parameter calculation section calculates the amount of variation in steam pressure in the dryer part from changes in various control II amounts, and the steam pressure is adjusted even for a new brand of paper. In order to optimize the pressure, this amount of change in steam pressure is applied to the feedback control 1ItIL to perform feedforward control, thereby drying the moisture content to the target value for a new brand of paper in a short time. The required steam pressure can be set automatically, reducing operator effort.

4.L of the drawing! Fig. 1 is a block diagram of one embodiment of the present invention, Fig. 2 is a plant model diagram of the dryer part of the above embodiment, Fig. 3 is an explanatory diagram showing the coating bar of the above embodiment, and Fig. 4 is a block diagram of an embodiment of the present invention.
FIG. 5 is an explanatory diagram of the level control operation of the coating agent in the coating bar of the above embodiment, FIG. 5 is an explanatory diagram of the dryer part of the above embodiment, and FIG. 6 is an explanatory diagram of the conventional example.

1... Paper web 2... Coating bar 3.5... Tank 4.17... Coating agent 6... Dryer part 7... Cylinder roll 9... Winding roll 12...
- Parameter calculation unit 13... Feedforward control unit 14... Feedback control unit 10.11.15... Sensor 16... Level t, lj control unit

Claims (1)

[Scope of Claims] A feedback control unit that compares the moisture content of paper in a dryer part, which is a subsequent stage of the coating device, with a target moisture content and performs feedback control of drying steam pressure based on the deviation. In the coating control device, when the brand of paper to be manufactured is changed, the required amount of change in steam pressure is calculated from the changes in the various control amounts, and this vapor pressure is added to the control amount from the feedback control section of the dryer part. A coating control device comprising a feed forward control section that applies a change amount.