JPS63295790A - Method and apparatus for controlling drawing of sheets - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Objective of the Invention) (Industrial Field of Application) The present invention aims to keep sheets, which are transported between rolls in a slack state, within a preferable slack range in the manufacturing and processing process of sheets, and The present invention relates to a control method and device that aims to prevent deterioration in the product quality of sheets and improve productivity by smoothly transporting sheets, and in particular, to control the slack position of sheets at multiple positions including abnormal zones. The present invention relates to a method and apparatus for controlling the draw of sheets, which is characterized by detecting the flow rate and performing optimal control accordingly.

<Prior art and its problems> For example, in a paper machine, in the first process, the raw material flows out as a dilute valve liquid onto a running endless mesh belt, and a paper web is formed on this mesh belt, and then the press in the next process It is transferred to a process, and further transferred at high speed and transferred to a dryer process to become a product.

By the way, in the process-to-process transfer of this paper machine, for example, when transferring the paper web from the initial process to the press process, it is generally required that the paper web be transferred in a slack state in which it hangs downward within a certain range between rolls that are spaced apart. Problems arise when this slack state is excessive or insufficient. In other words, if a paper web that does not have sufficient strength descends to the depth of the valley in the slack state (hereinafter referred to as the "sag position"), the structure of the paper web will collapse under its own weight, causing the paper web to become thick and thin, impairing product quality. If the slack position falls further, it will lead to a paper web cutting accident.On the other hand, if the slack position rises, the paper web will receive a tensile force, which will also cause the paper web to become thinner and thicker, impairing product quality. Become. In addition, another problem is that if the slack position rises, air will be allowed to enter between the paper web and the press blanket during transfer from the initial process to the press process, and the influence of this air will cause the paper web to deteriorate just before the press roll. This causes wrinkles to appear on the surface, which also impairs the quality of the product.

In this way, variations in the slack position of the paper web between rolls are directly related to product quality, and it is important to always maintain the slack position of the paper web within a certain tolerance range that is compatible with the paper machine. It is. Similar problems have arisen in the production or processing of resin films and other sheets.

Recently, due to advances in optical sensor technology, etc., it has become possible to continuously extract the amount of variation in the slack position of sheets as the amount of change in electrical signals, etc. Conventionally, the method of detecting the slack position of sheets using such an optical sensor is to attach two light-receiving parts of the sensor at the upper and lower limit values of the slack position. (hereinafter referred to as the "upper abnormal band"), a band within both limits (hereinafter referred to as the "normal band"), and a band below the lower limit value (hereinafter referred to as the "lower abnormal band"). A control method (hereinafter referred to as "three-position control method") is adopted. However, with the three-position control method, it is difficult to respond to the amount of change in the slack position, considering the fact that the slack position changes rapidly.Also, there is a growing demand for the normal zone to be as narrow as possible from the viewpoint of safety. Nevertheless, it is clear that if the three-position control method is implemented as is, it will not be able to respond to the amount of change, as in the case where the slack position changes suddenly. Conventionally, such cases have been dealt with by reducing the pulse width of the output pulse, but this method has not solved the problem of lowering the response, which is another problem.

Technical matters for which the development was attempted> The present invention was developed in view of the above-mentioned actual situation, and it is capable of gently converging the slack position to an allowable range, and also dealing with some rapid fluctuations in the slack position. A method for controlling the draw of sheets, which also has the functions of determining loss of control, detecting sheet cutting accidents, displaying abnormal conditions of slack positions, issuing alarms, and stopping control. This is an attempt to develop a device.

(Structure of the Invention) Means for Achieving the Object> That is, the sheet draw control method of the present invention is a control method for keeping the slack state of sheets transported between rolls in a slack state in an optimal state. The slack position is detected at multiple positions, including the abnormal band, and draw control is performed based on this detection result, and when the slack position of the sheet reaches the abnormal band, an interrupt control output is issued. This feature is intended to achieve the above objective.

In addition, the sheet draw control device of the present invention is a control device for maintaining the slack state of sheets transported between rolls in a slack state in an optimal state, and the sheet draw control device adjusts the slack position of the sheets at multiple positions including an abnormal zone. and a control section that performs draw control based on the detection result and issues an interruptive control output when the slack position of the sheets reaches an abnormal band. This is an attempt to achieve the above objective.

(Example) The present invention will be explained in detail below based on the illustrated embodiment. First, the device of the present invention will be explained, and its operation mode will be explained, and the method of the present invention will also be explained. Fig. 1 As shown in the figure, the sheet draw control device 1 of the present invention is used by being incorporated into an existing paper machine 2, etc., and is used between each process of the paper machine 2, for example, from the first wire process to the next process. A detector 5, which is a main component of the detection section that is the main part of the present invention, is installed at the transfer connection to the press process.This detector 5 is mainly composed of measurement members such as optical means and laser light. This detects the slack position of the sea 1-il [A that is transferred on the roll 3 provided at the transfer connection section.Then, the information (analog signal) obtained by the detection! A position setting device 9 is provided for converting the signal into a digital signal.Furthermore, at the downstream of this position setting device 9, there is a control panel 11 which is a main component of a control unit mainly composed of a combination of a sequencer, a timer, or a microcomputer. From this control panel 11, there is a display panel 12 for displaying and announcing information, an alarm 13, or as needed.
A recorder (not shown) capable of outputting various information, a control panel 14 responsible for switching between automatic operation and manual operation, etc. are connected. Furthermore, the control circuit from the control 111 passes through a potentiometer 15 to a motor M that directly controls the rotation speed of the roll 3.
These components constitute the draw control device 1 for the sheet 11 of the present invention.

Next, each component will be explained in more detail.

First, in this embodiment, the detector 5, which constitutes the essential part of the present invention, is based on a reflective optical sensor 6, and the sensor 6 outputs an analog electrical signal proportional to the slack position of the sheets A. Normally, the output current of these optical sensors 6 and the like is extremely small, so after being amplified by an amplifier 7, it is sent to the subsequent position setting device 9. Furthermore, these devices are housed in a case 8 to block harmful influences from the outside such as water droplets and moisture. Then, the analog electrical signal output from the detector 5 is transmitted to four reference lines (upper limit line HH1, upper tolerance line H1, lower tolerance line, lower tolerance line, Side limit line LL
) is output to the subsequent control panel 11 as a digital electrical signal via the A-D converter 10. The digital electrical signal input to the control panel 11 is sent to the operation panel 14 as a modified pulse output using a five-position control system to be described later. This control panel 11 is also equipped with an accident/abnormality diagnosis function, an inspection function, etc., and if control becomes uncontrollable, if wet paper runs out, or if a malfunction occurs, it will immediately stop the control, and at the same time Announcements are made through the display panel 12 and alarm 13. Furthermore, all of this control information is recorded and can be outputted via a recorder at any time if necessary. During normal operation, the operation panel 14 sends a signal to the drive mechanism of the motor M for one or both of the rolls 3 through the subsequent potentimeter 15, thereby increasing or decreasing the rotational speed of the roll 3. , controls the slack position of sheets A.

It also plays the role of switching between automatic and manual operation, and returning to operation.

The overall configuration of the present invention has been described above, and the five-position control method, which is a characteristic control method of the present invention described earlier, will be explained below. First, as shown in Figure 3, Sea 1-IJI
Regarding the slack position of A, the upper limit line HH is the reference line where the tensile force of the sheet IA increases if it is located above this and there is a risk of it being torn, and conversely, if it is located below this, the sheet IA The reference line that may break due to the weight of Class A is the lower limit line LL, and in the middle there are two reference lines, the upper tolerance line H1 and the lower tolerance line. The band above the upper limit line HH is the upper abnormal zone B HH, and the band between the upper limit line HH and the upper tolerance line H is the upper tolerance zone B.
H1 and the following are similarly defined downward as normal zone BHL - lower acceptable zone BL, lower abnormal zone B1, and L. That is, the aforementioned five-position control system divides the sheets into these three bands and controls the sheet type A.
The name comes from the fact that it detects and controls the slack position of the

Below, we will discuss the control actions in each state in detail in the second section.
This will be explained based on the diagram and FIG.

This FIG. 4 is a flowchart showing an example of the flow of the control program of the present invention, and although explanations corresponding to individual control steps will be omitted, the following describes some of the characteristic controls in this program. l
+! The three cases will be explained separately into cases (i) to (iv). Furthermore, what is indicated by the reference numeral 20 is a time-dependent slack position variation curve of the sheets A, which is a time-dependent representation of the change in the slack position of the sheets taken out by the detector 5. .

i) When the upper tolerance zone BH1 reaches the lower tolerance zone BL Consider the case shown in FIG. 2(i). First of all, normal zone B
When the slack position fluctuation curve 20 corresponding to ML reaches point a, the control panel 11 issues an accelerated pulse output 21 with a pulse width T1, thereby shifting the slack position 1 in the direction (downward) that relieves the tensile force of the sheet MA. Have them corrected. Also, after the acceleration pulse output 21 is generated, a waiting time T3 is set, and normally this waiting time T3 is set.
, neither the acceleration pulse output 21 nor the deceleration pulse output 22 is generated again.When the zeroth order reaches point b, the deceleration pulse output 22 of pulse width T2 is generated this time.

This will reduce the slack in the sheets (upward)
to correct the slack position. In this case as well, deceleration pulse output 2
2, a waiting time T3 is set.

ii) If the upper abnormal zone BI (n) is reached, the
). When the slack position fluctuation curve 20 reaches the 0 point, as in the case (i) above, the acceleration pulse output 21
occurs, and a waiting time T3 is counted from after the occurrence. However, if the slack position fluctuation curve 20 continues to rise further within this waiting time T3 and reaches point d, the acceleration pulse output 21 is issued again without waiting for this waiting time TI, and the slack position is moved downward. Command to make corrections. Further, when the upper limit line HH is exceeded and the upper abnormal band BHH is reached in this way, the upper limit time T H)I is counted from the time the upper limit line HH is reached. Although the explanation is omitted, the same applies when the lower abnormal band Bt,t is reached.

ii) If it does not return to 19 even after waiting the lower limit time THH, as shown in Figure 2 (iii), if it does not return to the upper tolerance band BH within the upper limit time THH, this upper limit time TM
After H elapses, the control panel 11 immediately determines that control is impossible, automatically stops the control, and at the same time turns on the display panel 12 and alarm 13.
Activate. Similarly, even if the lower limit time T LL is not returned, the control ill immediately determines that the control is uncontrollable and operates in the same manner as described above.

iv) When sheets A break If the slack position fluctuation curve 20 moves in the normal band BHI as shown in Figure 2 (iv), or in other cases, sheets A suddenly breaks for some reason. At that moment, the lower limit time TLL is counted, and after the elapse of that time, the control is immediately stopped and the display panel 12 and the alarm 13 are activated, as in (iii) above.

In the above embodiment, a five-position control system has been described, but by further providing a reference line, it is also possible to perform multiple divisions.Also, in the above embodiment, a reflective optical sensor 6 was used as the detector 5. In addition to this optical sensor 6, various sensors having functions that replace it can be used. Furthermore, the control panel 11 is not limited to a sequencer, a timer, etc., and may be controlled by a microcomputer. Further, the installation location of the detector 5 is not limited to the location in the above embodiment, and can be appropriately installed at a location where cutting accidents of sheets A occur frequently or a location where product quality deterioration occurs.

(Effects of the Invention) The present invention has the four configurations described above, and exhibits the following effects. That is, in the multi-position control system according to the present invention, even if the slack position changes rapidly, it cannot be further responded to even if the acceleration pulse output 21 or deceleration pulse output 22 that suppresses this change is generated once or multiple times. Even in such cases, a two-stage output method is adopted in which an output pulse is generated in an interruptive manner when the slack position reaches an abnormal position. By adopting this two-stage output method, the pulse widths Tl and T2 of the output pulses can be made smaller, which can meet the demand for making the normal band BHL narrower. As described above, the present invention can cope with rapid changes in the slack position, and also makes the normal zone BHL narrower to control the slack position. Therefore, according to the present invention, it is possible to always perform highly reliable control that can almost completely prevent cutting of sheets A in advance, thereby preventing deterioration of product quality of sheets A and accidents caused by cutting of sheets A. As a result, productivity is improved.

Further, according to the present invention, it is possible to determine loss of control and detect cutting accidents at the locations where sheets A are loosened, and it is easy to take corresponding measures1, which is extremely valuable in terms of process control.

[Brief explanation of drawings]

Fig. 1 is a skeletal configuration diagram showing an embodiment of the present invention, Fig. 2 is a diagram of the operating principle in each state of the multi-position control system, and Fig. 3 is an enlarged view of the slack position of sheets transferred between rolls. The skeleton diagram shown in FIG. 4 is a flowchart showing an example of the control program of the present invention. 1; sheet draw control device 2; paper machine 3; roll 5; detector 6; optical sensor 7: amplifier 8; case 9; position setting device 10; A-D converter 11; control panel 12; display panel 13 Alarm 14; Operation panel 15; Potentiometer 20; Slack position fluctuation curve 21; Acceleration pulse output 22; Deceleration pulse output A; Sheets M; Motor HH; Upper limit line H; Upper tolerance line L; Lower tolerance line LL; Lower limit line B o si 'i Upper abnormal zone BI (; Upper tolerance zone B HL i Normal zone BL; Lower tolerance zone B LL; Lower abnormal zone Tl; Pulse width (acceleration pulse output) T2 , Pulse [(of deceleration pulse output) T3; Standby time THH; Upper limit time TLL; Lower limit time

Claims (8)

[Claims] (1) In a control method for maintaining the optimal slack state of sheets that are transported between rolls in a slack state, the slack position of sheets is detected at multiple positions, including the abnormal band, and this detection result is used to A draw control method for sheets, etc., characterized in that the control is performed and, when the slack position of the sheets reaches an abnormal band, a control output is generated in an interruptive manner. (2) The sheet draw control method according to claim 1, which includes a function of also detecting the cutting state of the sheet when detecting the slack position. (3) The sheet draw control method according to claim 1 or 2, which includes a function of determining uncontrollability. (4) A patent claim that includes a function to automatically stop control in the case of detecting a cutting accident of the sheet at the position where the slack position is detected, or in the case of determining that the control is uncontrollable, or both. A method for controlling the draw of sheets according to the first, second or third scope. (5) In a control device for maintaining the slack state of sheets transported in a slack state between rolls in an optimal state, a detection unit that detects the slack position of sheets at multiple positions including an abnormal band; In addition to controlling the draw based on the result,
A draw control device for sheets, comprising: a control section that issues a control output in an interruptive manner when the slack position of the sheets reaches an abnormal band. (6) The sheet draw control device according to claim 5, characterized in that, in detecting the slack position, the apparatus has a function of also detecting the cutting state of the sheet at this detection position. (7) The sheet draw control device according to claim 5 or 6, wherein the control section has a function of determining uncontrollability. (8) A function that automatically stops control in either one or both of the cases where the detection unit detects a cutting accident of the sheet at the slack position detection point, and the control unit determines that control is impossible. A sheet draw control device according to claim 5, 6, or 7, characterized in that the device comprises: