JPH02182992A - Detection of mixed flow of paper machine - Google Patents

Abstract

PURPOSE:To detect fixed flow accurately at a real time by jetting ink in the width direction of paper stock at equal intervals in the vicinity of a feed opening of paper stock by a marker and detecting deviation of position of ink mark by a mark detection device arranged in the downstream. CONSTITUTION:Ink is jetted from a marker 5 to a paper layer and a linear mark by ink is formed on the paper layer. Ink is made to flow according to orientation of fiber in traveling, state of mixed flow at a wet part is detected by a detector 13a and contraction state of paper in a dryer is recognized by a detector 13b to weigh and control the amount of mixed flow.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for detecting diagonal flow in a paper machine for controlling paper layer formation such as basis weight in a paper machine.

[Prior art] In a paper machine, the stock suspension that exits the head box is transferred onto the wire, and then dehydrated as it runs along with the wire running at high speed, so that the direction of the fibers is relatively aligned. After forming a paper layer in this state, it is conveyed to a press part via couch rolls.

In such a case, if the orientation of the fibers on the wire is non-uniform, this tendency is further amplified in the dry part and has a decisive effect on the quality of the paper as a final product.

In particular, controlling the uniformity in the width direction in a paper machine is important.

Therefore, it is required that the stock is suspended as uniformly as possible in the headbox, but the so-called diagonal flow, in which the orientation of the fibers already latent in the headbox deviates diagonally from the direction of movement of the stock, This becomes apparent when the stock is discharged from the stock supply port onto the free surface, and is further amplified when a paper layer is formed on the wire, eventually causing uneven thickness in the width direction.

Therefore, it is very important to understand the diagonal flow quantitatively in order to control the equal basis weight by adjusting the slicing opening of the stock supply port, and it is especially essential for automatically controlling the paper machine. It is something.

Conventionally, there was no means for detecting the above-mentioned mixed flow, and unevenness in basis weight was detected by scanning in the width direction using a B/M meter.

[Problem to be solved by the invention] However, even if scanning is performed at right angles to the running direction of the paper stock in the paper machine, the paper stock is traveling at high speed even during scanning, so the distance from the stock supply port is the same. Rather than scanning in the width direction, it is measuring different parts at diagonal positions, and it is difficult to say that the actual width direction basis weight distribution is being detected. There was no way to detect irregularities in basis weight caused by this.

The present invention solves these drawbacks, makes it possible to accurately detect actual mixed flow in real time, and uses this to control basis weight unevenness, thereby making it possible to control basis weight with higher accuracy. It is.

[Means for Solving the Problems] The present invention jets ink simultaneously over the entire width of the stock at equal intervals in the width direction of the stock using a marker provided on the stock supply date R from the head box, thereby preventing the slanting of the stock. This invention relates to a method for detecting a diagonal flow in a paper machine, characterized in that a mark detection device disposed downstream detects a shift in the position of an ink mark formed according to the flow of the ink.

[Operation] Ink is jetted onto the paper layer from a marker such as an inkjet to form a linear mark on the paper layer.
Ink flows according to the orientation of the running fibers, and detection devices placed after the wet and dry parts of the paper machine detect the state of diagonal flow in the wet part and the state of paper shrinkage inside the dryer in the dry part. You can know accurately in real time.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, and as shown in FIG. Markers 5 made of inkjet or the like having several nozzles 4 are arranged at regular intervals.

Connected to said marker 5 is a conduit 8 which leads ink from an ink container 6 via a pump 7 .

First and second detection devices 13a, such as television cameras, detect ink linear marks at two locations: at the end of the wet part 9, after the couch roll 1O, and at the rear of the dry part 11, in front of the take-up roll 12. , 13b are arranged.

An arithmetic and control device 14 is connected to the first and second detection devices 13a and 13b, and a recorder 15 for printing out data and a display 1B such as a television are connected to the arithmetic and control device 14. In the figure, 17 shows the wire of the wet part 9, 18 shows the press part, and 19 shows the calender roll.

As described above, when the adjustment stage of the paper machine 3 is finished and the steady state is reached, ink is supplied from the ink container 6 to the marker 5 using the pump 7 for a certain period of time (for example, 1 minute), and the marker 5 such as an inkjet Ink is ejected from the wire 17 to form a linear mark on the paper stock moving on the wire 17.

At the starting end of the wire 17, the fibers are not yet fixed and are in a suspension state, so the ink also flows according to the orientation of the fibers, and when the paper stock forms a diagonal flow, the shape of the diagonal flow is changed by the ink. It clearly appears on the paper layer.

A first detection device 13a provided at the rear of the couch roll 10 and before the stock is transferred to the press part 18,
A linear mark made of the ink is detected. In such a case,
The diagonal flow rate in the paper layer forming section can be determined via the arithmetic and control device 14 from the difference between the distance between each mark detected by the detection device 13a and the distance between the nozzles 4 of the marker 5 that ejected ink.

Furthermore, irregularities in the flow of paper stock can be detected by displaying the irregularities in the flow of paper stock on the display 16 from the degree of disturbance or blurring of linear marks caused by ink.
It is also possible to easily guess and select the locations where the opening degree should be finely adjusted.

A second detection device 13b disposed at the rear of the dry part 11 and at the front of the take-up reel 12 also detects the linear mark made of ink. Detection is performed every few minutes after the papermaking reaches a steady state or just before the winding is completed.

In the dry part 11, shrinkage in the width direction is large in areas where the paper thickness is thin and areas with high moisture content, but the marks detected by the first detection device 13a and the marks detected by the second detection device 13b are compared, and the data is calculated and controlled. By sending the paper to the device 4, the state of paper shrinkage in the dry part 11 caused by the diagonal flow is quantitatively detected.

By detecting the above-mentioned detection values in real time using an arithmetic and control device or the like, the operator can quickly and accurately know the points to be adjusted, thereby making it possible to control the basis weight more reliably.

Note that the method for detecting mixed flow in a paper machine according to the present invention is not limited to the above-described embodiments, and even if ink is continuously ejected by a marker to form a linear mark,
Also, it is possible to form dot marks intermittently, and the same effect can be achieved in a colorless manner by using a solution of radioactive elements such as isotopes instead of ink, which deviates from the gist of the invention. Of course, various changes can be made within the scope.

[Effects of the Invention] As explained above, according to the method for detecting mixed flow in a paper machine of the present invention, various excellent effects as described below can be achieved.

■ By jetting ink from a marker to the paper stock supply opening of the head box at equal intervals in the width direction of the paper stock, the ink flows in a diagonal flow in the paper layer forming section, making it possible to detect marks made by the ink downstream. By detecting it with a device, the diagonal flow rate can be determined quickly and accurately.

■ Also, the basis weight can be accurately controlled by ■.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of an apparatus for carrying out the method of the present invention. l is the head box, 2 is the stock supply port, 4 is the nozzle, 5
is a marker, 6 is an ink container, 13a is a first detection device,
13b is a second detection device, 14 is an arithmetic and control device, and 16 is a display device.

Claims (1)

[Claims] 1) Markers installed near the stock supply port from the head box simultaneously jet ink across the entire width of the stock at equal intervals in the width direction of the stock, and mark the position of the ink marks formed according to the diagonal flow of the stock. A method for detecting mixed flow in a paper machine, characterized in that a shift is detected by a mark detection device disposed downstream.