JPH08260376A - Unit weight profile controller for paper-making machine and its controlling method - Google Patents

Abstract

PURPOSE: To obtain a controller for paper grammage which can operate the paper grammage adjuster using air flows on the basis of detection of the unevenness profile of the paper stock on the paper-making wires to give paper of uniform basis weight. CONSTITUTION: In the paper-making machine, the paper stock is fed from the head box 2 on the wire cloth 1, simultaneously the unevenness profile f the paper stock is detected by transversely reciprocating the unevenness detector 3 comprising a non-contact type displacement sensor and the output is input to a computer. The computer compares the profile with the previously memorized unevenness profile to computing the thickness profile of the paper stock. On the basis of the result, the thickness profile of the paper stock corresponding to the jetting positions and pressure of the transversely reciprocating air nozzles in the grammage adjuster is computed and the grammage adjuster 4 is driven and controlled based on the computation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a basis weight profile controller for a paper machine and a control method thereof for adjusting the basis weight of a paper in the width direction to produce a paper having a good basis weight profile.

[0002]

2. Description of the Related Art Generally, paper is manufactured by causing a stock material, which is uniformly dispersed in a head box, to flow onto a wire, dehydrated, and dried. In order to produce a paper having a good basis weight profile, the basis weight can be adjusted in a step before the press machine. Here, the uniformity of the basis weight profile is determined by the dispersed state in the head box, the uniform outflow of the stock material onto the wire, and the like.

In order to make the dispersion state of the paper stock in the headbox uniform, the recent headbox has been improved to a nearly ideal state. Further, there is also known a method of adjusting a basis weight profile by using a head box capable of changing the raw material concentration in each position in the width direction. (IHI "IHI-V
Introduction of OITH new type headbox "Pulp and Paper Technology Association, 1994 Annual Meeting Summary, 1994, p35-p42)

As a method of controlling the uniform outflow of the stock onto the wire, a generally used method is to adjust the opening degree of the slice lip for ejecting the stock from the head box onto the wire in the width direction. Is the way. Further, regarding a device for adjusting a grammage profile by air in which at least one nozzle for injecting air is installed in the width direction of the wire, the applicant of the present invention has proposed a Japanese Patent Application No.
No. 317093 is filed. When this basis weight adjusting device is used, for example, the width direction of the paper is 10 mm width (10 m
It is possible to adjust the local basis weight (m to 100 mm width is possible).

[0005]

When producing paper with a good basis weight profile, it is important to have a uniform outflow of stock on the wire. The wire of a paper machine has minute unevenness in the width direction, and it is difficult to eliminate it. The minute unevenness in the width direction existing in the wire of this paper machine forms an uneven uneven profile of the stock material, resulting in non-uniformity of the basis weight profile. Since there is no paper machine equipped with a control method that takes into consideration the uneven profile of the stock material, it is not possible to produce paper having a better basis weight profile.

An object of the present invention is to provide a paper machine capable of producing paper having a good basis weight profile by effectively using a basis weight adjusting device using air.

[0007]

[Means for Solving the Problems] As a result of earnest research in view of the above, the unevenness detection device installed on the wire of the paper machine detects unevenness of the stock material at a plurality of positions of the paper, and the obtained unevenness profile allows air By controlling the grammage adjusting device according to the above, the grammage adjusting device can be effectively used, and a paper machine capable of producing paper having a good grammage profile has been invented.

That is, the basis weight profile control device for a paper machine according to the present invention comprises a concavo-convex detecting device for detecting concavities and convexities of a stock material in the width direction on a wire of the paper machine and at least one air blower in the width direction. It is characterized in that an air-based basis weight adjusting device equipped with a nozzle is additionally provided.

Preferably, the unevenness detecting device is a non-contact type displacement sensor.

In the basis weight profile control method for a paper machine of the present invention, the unevenness profile Y1 of the paper stock in the width direction of the wire of the paper machine is detected by the unevenness detection device including the non-contact type displacement sensor and set in advance. After calculating the stock thickness profile Y2 from the uneven profile Y0 in the width direction of the wire, the air-based stock thickness profile Y3 corresponding to the grammage adjusting device using air.
Is calculated and the basis weight adjusting device is driven and controlled by the air.

The grammage profile control device and control method for the paper machine of the present invention will be described in more detail below.

The paper machine of the present invention is preferably a Fourdrinier paper machine, a hybrid former, or the like having a free surface in at least a part of the initial dewatering region on the wire.

On the wire of the paper machine of the present invention, an unevenness detecting device and a grammage adjusting device using air are installed. At this time, the unevenness detection device is installed immediately before the grammage adjustment device using air. By installing immediately before, the uneven profile to be adjusted by the grammage adjusting device using air can be accurately detected. Further, for the purpose of monitoring the amount of change in the unevenness of the paper material, it is possible to install the unevenness detecting device immediately after the basis weight adjusting device using air. At this time, feedback control is also possible by using the data of the unevenness detection device installed immediately after the air-based basis weight adjustment device.

A device having a non-contact type displacement sensor is preferably used as the unevenness detecting device installed on the wire of the paper machine of the present invention. The non-contact displacement sensor is
A structure that can move in the horizontal direction is preferable.Furthermore, there is a drive motor on the column to which the sensor is attached, the sensor is automatically reciprocated in the width direction of the paper, and the output signal from the sensor is transferred to the computer. It is preferable to automatically detect the uneven profile of the material.

The non-contact displacement sensor according to the present invention is
It is preferable that the working distance is 10 mm or more and the resolution is 0.5 mm or less. As the type of the non-contact displacement sensor, a sensor whose principle is a reflection time of a transmitted wave from an ultrasonic transducer, or a sensor which measures a deviation of a reflection spot of laser light irradiated at a certain angle on the surface is used. be able to.

The grammage adjusting device based on air installed on the wire of the paper machine of the present invention has one or more air nozzles for injecting air to the paper material on the wire. The air output is controlled at the position selected by the uneven profile obtained by the unevenness detection device. As a method of adjusting the output of air, a method of manually adjusting the air piping with a pressure reducing valve, a method of automatically adjusting the air piping with a solenoid valve, and the like can be considered. As a method of injecting air to the selected position, using an air nozzle equipped with a mechanism capable of horizontal movement in the width direction of the paper, moving to a position where the grammage is to be adjusted, and a method of injecting air, Alternatively, a method of arranging a plurality of air nozzles in the width direction of the paper and injecting air with the air nozzle at a position where the grammage is desired to be adjusted can be considered.

The paper machine of the present invention can be used in combination with the conventional method of adjusting the opening degree of the slice lip for ejecting the stock onto the wire from the head box in the width direction and controlling the basis weight profile. You can Furthermore, the present invention is not limited to these, and various modifications are possible.

[0018]

[Function] A non-contact type displacement sensor is installed on the wire of the paper machine, and the unevenness of the paper material on the wire is measured to select the air injection position and the air injection pressure, etc. Setting becomes easy, paper with a good basis weight profile can be manufactured, and effective use of air becomes possible.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A grammage profile controller for a paper machine according to the present invention will be described below with reference to the drawings.

Example 1 FIG. 1 is a schematic diagram showing the relationship between a grammage profile control device for a paper machine and a wire device for a paper machine according to the present invention. The head box 2 of the paper machine shown in FIG. 1 supplies a stock containing pulp or the like to the reticulated wire device 1. On the wire device 1, an unevenness detection device 3 and a grammage adjustment device 4 using air are attached. The unevenness detection device 3 is installed immediately before the grammage adjustment device 4 using air.

FIG. 2 is an enlarged perspective view of the unevenness detecting device 3 of FIG. The unevenness detection device 3 has an arch 12 installed so as to straddle the wire device 1, and a non-contact displacement sensor 11 that detects unevenness of the liquid stock material on the wire device 1 is attached. The non-contact displacement sensor 11 is movable in the horizontal direction. Further, the arch 12 has a driving motor and automatically reciprocates the sensor in the width direction of the paper. The output signal from the non-contact type displacement sensor 11 is transferred to a computer, and the uneven profile of the paper material is automatically detected.

FIG. 3 is an enlarged perspective view of the grammage adjusting device 4 using the air of the air nozzle fixed type shown in FIG. In the grammage adjusting device 4 using air, an arch 22 is installed so as to straddle the wire device 1, and a plurality of air nozzles 21 for ejecting air to the liquid paper material on the wire device 1 are arranged in the width direction. Air is jetted by the air nozzle corresponding to the position selected by the unevenness profile obtained by the unevenness detector 3. Each nozzle is equipped with a solenoid valve in the air pipe to control the output of air.

FIG. 5 is a flow chart of processing by the grammage profile controller of the paper machine.

In step 1, the electric signal representing the unevenness detected by the unevenness detecting device 3 can be interpreted as a widthwise detection profile based on the position information of the non-contact displacement sensor 11. The obtained detection profile is subjected to processing such as smoothing to obtain the uneven profile Y1.
(X). At this time, since the unevenness detecting device 3 is located immediately before the grammage adjusting device 4 using air, the mapping process generally performed in the grammage profile control of the paper machine is not necessary.

Here, the smoothing is one of the processes generally performed by the currently commercially available detectors, and the detected value is calculated with the previously detected value at the same position. However, this is a method of reducing noise.

Here, the mapping means converting the position information in the width direction of the paper, which is detected when the paper is dried, into the position information when the head box 2 and the wire device 1 are present. This is as the paper dries
The cause is the phenomenon that the length of the paper in the width direction shrinks. If the detection device and the adjustment device are adjacent to each other as in the present invention, the mapping process is not necessary.

In step 2, the uneven profile Y
1 (X) is a purely uneven profile of paper stock, so the uneven profile Y of the wire detected in advance Y
0 (X) is taken and the stock thickness profile Y2
(X).

Here, the uneven profile Y0 (X) of the wire detected in advance is the uneven profile detected without supplying the paper material on the wire. At this time, whether or not the displacement profile Y0 (X) is detected while using the sliding function of the paper machine is determined when the paper material is actually supplied and the displacement profile Y1 (X) is detected. It depends on whether or not the dynamic function is used.

Here, the sliding function of the paper machine means that the wire of the wire device is about 50 to 10 perpendicular to the flow direction.
It is a function of reciprocating 0 mm. It is now commonly used on paper machines.

In step 3, the paper stock thickness profile Y2 (X) is calculated as the air-compatible paper stock thickness profile Y3 (X) corresponding to the air basis weight adjusting device 4. This is because the paper stock thickness profile Y2 (X) is detected every 10 mm in the width direction of the paper, whereas the adjustable width of the basis weight adjusting device by air is every 20 mm.
This is a calculation for obtaining the average value of two detection values for 20 mm corresponding to this.

In step 4, the basis weight adjusting device 4 by air is driven and controlled by the air-compatible paper material thickness profile Y3 (X) obtained in step 3.

These Y3 (X) values obtained by the means according to the flow chart in FIG. 5 are data before the basis weight control by the basis weight adjusting device 4 by air is always performed. This makes it possible to accurately monitor Y3 (X), which changes over time, and facilitates the selection of the position where the air is jetted.

Example 2 In Example 1, the air-based basis weight adjusting device is replaced with an air-based basis weight adjusting device having a plurality of horizontally movable air nozzles. FIG. 4 is an enlarged perspective view of an air nozzle movable type air-based basis weight adjusting apparatus including an air nozzle 31 that is movable in the horizontal direction. Similar to the first embodiment, the arch 32 is installed so as to straddle the wire device 1. The arch 32 includes a moving table 33 that can move in the horizontal direction.
3, an air nozzle is attached. The air nozzle is moved to a position selected by the uneven profile obtained by the unevenness detection device 3, and air is jetted. The devices and processes other than the grammage adjusting device using air are the same as in the first embodiment.

[0034]

As is apparent from the above, by using the grammage profile control device of the paper machine according to the present invention, the grammage adjusting device using air can be efficiently used, and the grammage can be adjusted even when the local grammage varies. Provided is a basis weight profile control device for a paper machine, which is capable of producing paper with a good profile.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a relationship between a grammage profile control device of a paper machine and a wire device of the paper machine.

FIG. 2 is an enlarged perspective view of the unevenness detection device.

FIG. 3 is an enlarged perspective view of a grammage adjusting device using air of a fixed air nozzle type.

FIG. 4 is an enlarged perspective view of a grammage adjusting device using movable air of an air nozzle.

FIG. 5 is a flowchart of processing by a grammage profile control device of a paper machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wire device 2 Head box 3 Unevenness detection device 4 Basic weight adjustment device by air 11 Non-contact type displacement sensor 12 Arch 21 Air nozzle 22 Arch 31 Air nozzle 32 Arch 33 Moving table

Claims (3)

[Claims] 1. A paper machine wire is provided with an unevenness detecting device for detecting unevenness of a stock material in a width direction and a grammage adjusting device using air having at least one air nozzle in the width direction. Basis weight profile control device for paper machines. 2. The basis weight profile control device for a paper machine according to claim 1, wherein the unevenness detection device is a non-contact displacement sensor. 3. An unevenness detecting device comprising a non-contact type displacement sensor detects an unevenness profile Y1 of a stock material in a width direction of a wire of a paper machine, and detects from a preset unevenness profile Y0 of the wire in the width direction. After calculating the stock material thickness profile Y2, the air-compatible paper material thickness profile Y3 corresponding to the air-based basis weight adjusting device is calculated, and the air-based basis weight adjusting device is drive-controlled. Basis weight profile control method.