阅读说明：本技术 超级压光机及线压值控制方法 (Super calender and linear pressure value control method ) 是由 陈清坤 于 2020-05-29 设计创作，主要内容包括：本申请涉及一种超级压光机及线压值控制方法,该超级压光机包括控制系统、与控制系统耦接的驱动机构、与驱动机构连接的压光辊组和与控制系统耦接的压力提供机构；驱动机构用于提供驱动力；压光辊组用于在驱动机构所提供驱动力对应的车速下传送纸张；压力提供机构用于给压光辊组施加压力,以调节压光辊组之间的线压值；控制系统设有第一预设模式,第一预设模式用于表征车速和线压值之间的关系,控制系统在车速处于升降速阶段时,按第一预设模式获取与当前的车速对应的线压值,进而控制压力提供机构对压光辊组施加与所获取的线压值相应的压力,以使得纸张的压光参数处于第一预设范围内。通过上述方式,本申请可以提高纸张在升降速阶段的压光质量。(The application relates to a super calender and a line pressure value control method, wherein the super calender comprises a control system, a driving mechanism coupled with the control system, a calender roll group connected with the driving mechanism and a pressure providing mechanism coupled with the control system; the driving mechanism is used for providing driving force; the press roller group is used for conveying paper at a speed corresponding to the driving force provided by the driving mechanism; the pressure providing mechanism is used for applying pressure to the calender roll group so as to adjust the line pressure value between the calender roll groups; the control system is provided with a first preset mode, the first preset mode is used for representing the relation between the vehicle speed and the line pressure value, when the vehicle speed is in a speed increasing and reducing stage, the control system obtains the line pressure value corresponding to the current vehicle speed according to the first preset mode, and then the pressure providing mechanism is controlled to apply pressure corresponding to the obtained line pressure value to the press roller group, so that the press roller parameters of the paper are in a first preset range. By means of the mode, the calendering quality of the paper at the speed increasing and reducing stage can be improved.)

1. A supercalender, characterized by comprising:

a control system;

a drive mechanism coupled to the control system for providing a driving force;

the calendering roller group is connected with the driving mechanism and used for conveying paper at a speed corresponding to the driving force provided by the driving mechanism;

a pressure providing mechanism coupled to the control system for applying pressure to the stack of rollers to adjust line pressure values within the stack of rollers;

the control system is provided with a first preset mode, the first preset mode is used for representing the relation between the vehicle speed and the line pressure value, when the vehicle speed is in a speed increasing and reducing stage, the control system acquires the line pressure value corresponding to the current vehicle speed according to the first preset mode, and then controls the pressure providing mechanism to apply pressure corresponding to the acquired line pressure value to the press roller group, so that press roller parameters of paper are in a first preset range.

2. Supercalender according to claim 1, characterized in that the control system is further provided with a second preset mode for characterizing the relation between the difference between calendering parameters and first target parameters and the line pressure value; when the vehicle speed is in a stable speed stage, the control system acquires the line pressure value corresponding to the difference value between the current calendering parameter and the first target parameter according to the second preset mode, and further controls the pressure providing mechanism to apply pressure corresponding to the acquired line pressure value to the calendering roller group, so that the difference value between the calendering parameter of the paper and the first target parameter is in a second preset range.

3. The supercalender according to claim 2, further comprising a man-machine circuit connected to the control system for displaying the calendering parameters and displaying images corresponding to the first and second preset modes, respectively.

4. Supercalender according to claim 3, characterized in that,

the image corresponding to the first preset mode comprises a first curve segment displayed in an acceleration stage in the acceleration and deceleration stage and a second curve segment displayed in a deceleration stage in the acceleration and deceleration stage; and displaying the image corresponding to the second preset mode as a third curve segment, wherein the third curve segment is connected between the first curve segment and the second curve segment and further displayed as the same curve.

5. The supercalender according to claim 1, further comprising a detection mechanism, coupled to the control system, for detecting the calendered paper along the axial direction of the calender stack and acquiring a plurality of calendering parameters of the paper distributed along the axial direction of the calender stack; the control system is used for calculating a plurality of calendering parameters distributed along the axial direction of the calendering roller group of the paper to obtain calendering uniformity;

the control system is preset with a third preset mode, the third preset mode is used for representing the relationship between the calendering uniformity and the line pressure value, the control system is used for acquiring the line pressure value corresponding to the calendering uniformity according to the third preset mode, and controlling the calendering roller group to adjust the corresponding position along the axis direction of the calendering roller group, so that the pressure corresponding to the acquired line pressure value is formed at the corresponding position between the calendering roller groups, and the calendering uniformity is further within a third preset range.

6. Supercalender according to claim 5, characterized in that the calendering uniformity is the difference between each of a plurality of the calendering parameters of the paper and a second target parameter; or the control system is used for calculating a plurality of calendering parameters of the paper distributed along the axial direction of the calendering roller group to obtain a 2sigma value, and the calendering uniformity is the difference value between the 2sigma value and a 2sigma target value.

7. Supercalender according to claim 5, characterized in that the stack of calendering rolls comprises a first crown roll and at least one work roll arranged side by side; the pressure providing mechanism is arranged adjacent to the first controllable middle-high roller and is used for applying pressure to the first controllable middle-high roller; the first controllable medium-high roller and the working roller are used for threading paper to carry out calendaring treatment on the paper;

wherein the first variable-crown roll has a plurality of first pressure adjustment zones distributed along an axial direction thereof, and the control system is configured to adjust the pressure between the corresponding position corresponding to the first pressure adjustment zone and the adjacent work roll.

8. The supercalender according to claim 7, characterized in that the stack of calendering rollers comprises a second crown roll arranged on the side of the at least one work roll remote from the first crown roll, the paper being fed in sequence between the second crown roll and the work roll and between the first crown roll and the work roll, the detection means being adapted to detect calendering parameters of the calendered paper fed between the first crown roll and the work roll;

the second controllable crown roll has a plurality of second pressure adjustment zones distributed along an axial direction thereof, and the control system is further configured to adjust a pressure between the corresponding position corresponding to the second pressure adjustment zone and the adjacent work roll.

9. Supercalender according to claim 8, characterized in that the number of the at least one work roll is 8, arranged in sequence between the first and second crowned rolls;

the working roll adjacent to the first controllable medium-high roll, the working roll separated from the first controllable medium-high roll by two working rolls, the working roll adjacent to the second controllable medium-high roll and the working roll separated from the second controllable medium-high roll by two working rolls are set to be metal hot rolls, the rest working rolls are set to be rubber covered rolls, and hot water is stored in the metal hot rolls.

10. Supercalender according to any of claims 1-9, characterized in that the calendering parameters comprise the thickness value and/or the gloss value of the paper after calendering.

11. A line pressure value control method applied to a supercalender according to any of claims 1 to 10, characterized by comprising:

judging whether the vehicle speed is in a speed increasing and decreasing stage;

if so, acquiring the current vehicle speed, and acquiring the line voltage value corresponding to the current vehicle speed according to the first preset mode;

controlling the pressure providing mechanism to apply pressure corresponding to the acquired line pressure value to the calendering roller group so that the calendering parameter of the paper sheet is in the first preset range.

Technical Field

The invention relates to the technical field of papermaking, in particular to a super calender and a linear pressure value control method.

Background

In the production process of paper making, a supercalender is a kind of calendering equipment commonly used in paper making, and the supercalender is a key equipment for determining whether the glossiness or thickness of the surface of the calendered paper reaches the quality index. The surface of the base paper is uneven or the glossiness of the base paper does not meet the requirement, and further the base paper needs to be subjected to surface calendering treatment.

The speed of a supercalender generally goes through the stage of speeding up and down in work, and during the stage of speeding up and down, the change of speed of a motor vehicle leads to the line pressure that is difficult to carry out the calendering to the paper and adjusts the size, and present conventional means is just to utilize the manual work to adjust line pressure, and nevertheless the manual work is difficult to find corresponding line pressure and its instantaneous speed of a motor vehicle according to the transform of speed of a motor vehicle and matches, and then can seriously influence the calendering quality of paper at the stage of speeding up and down.

Disclosure of Invention

Therefore, it is necessary to provide a supercalender and a line pressure value control method capable of improving the calendering quality of the supercalender in the speed increasing and decreasing stages, aiming at the problem that the conventional supercalender is not high in the quality of paper in the speed increasing and decreasing stages.

In order to solve the technical problem, the application adopts a technical scheme that: providing a supercalender comprising a control system, a driving mechanism coupled with the control system, a calender roll group connected with the driving mechanism and a pressure providing mechanism coupled with the control system; wherein the driving mechanism is used for providing driving force; the calender roll group is used for conveying paper at a speed corresponding to the driving force provided by the driving mechanism; the pressure providing mechanism is used for applying pressure to the roller groups so as to adjust the line pressure value between the roller groups;

the control system is provided with a first preset mode, the first preset mode is used for representing the relation between the vehicle speed and the line pressure value, when the vehicle speed is in a speed increasing and reducing stage, the control system acquires the line pressure value corresponding to the current vehicle speed according to the first preset mode, and then controls the pressure providing mechanism to apply pressure corresponding to the acquired line pressure value to the press roller group, so that press roller parameters of paper are in a first preset range.

In order to solve the above technical problem, another technical solution adopted by the present application is: the linear pressure value control method is applied to the supercalender and comprises the following steps:

judging whether the vehicle speed is in a speed increasing and decreasing stage;

if so, acquiring the current vehicle speed, and acquiring the line voltage value corresponding to the current vehicle speed according to the first preset mode;

controlling the pressure providing mechanism to apply pressure corresponding to the acquired line pressure value to the calendering roller group so that the calendering parameter of the paper sheet is in the first preset range.

The beneficial effect of this application is: be different from prior art's condition, this application is equipped with first preset mode, and first preset mode can acquire the line pressure value that corresponds with current speed of a motor vehicle when the speed of a motor vehicle is in the speed up-down stage, and then control pressure provides the mechanism and applys the pressure that corresponds with the line pressure value that acquires to the press polish roller group to make the press polish parameter of paper be in first preset scope. Through the setting of the first preset mode, the calendering parameters of the paper calendered by the supercalender in the speed-up and speed-down stage can be kept within a first preset range, and the condition that the quality of the paper is not high and the paper needs to be rewound in the speed-up and speed-down stage is reduced.

Drawings

FIG. 1 is a schematic perspective view of a portion of an embodiment of a supercalender of the present application;

FIG. 2 is a schematic structural view of an embodiment of the supercalender of the present application;

FIG. 3 is a schematic diagram of the variation of linear pressure versus vehicle speed for an embodiment of the supercalender of the present application;

FIG. 4 is a schematic view of a part of the construction of a first controllable crown roll of the supercalender shown in FIG. 1;

FIG. 5 is a flow chart of line pressure control for an embodiment of the supercalender of the present application.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "inner", "outer", "left", "right" and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

Referring to fig. 1 and 2, fig. 1 is a partial perspective view of an embodiment of a supercalender of the present application, and fig. 2 is a schematic view of the structure of the embodiment of the supercalender of the present application. An embodiment of the supercalender of the present application comprises a control system 10, a drive mechanism 20 coupled to the control system 10, a calender stack 30 connected to the drive mechanism 20 and a pressure providing mechanism 40 coupled to the control system 10.

The drive mechanism 20 is used to provide a driving force. The calender roll group 30 is used to convey the sheet at a vehicle speed corresponding to the driving force provided by the driving mechanism 20. That is, the calendar roll group 30 rotates by the driving force provided by the driving mechanism 20, and conveys and calenders the sheet at the vehicle speed by the rotation. The pressure providing mechanism 40 is used to apply pressure to the stack 30 to adjust the line pressure between the stack 30. The line pressure value is the amount of pressure per unit distance exerted by the calender roll stack 30 on the sheet. The line pressure value is unchanged, the slower the vehicle speed is, the higher the glossiness of the paper is, and the faster the vehicle speed is, the lower the glossiness is. When the vehicle speed is constant, the higher the linear pressure value is, the higher the glossiness of the paper is, and the lower the linear pressure value is, the lower the glossiness of the paper is.

The control system 10 is provided with a first preset mode for characterizing the relationship between vehicle speed and line pressure values. For example, the vehicle speed and the line pressure value may be positively correlated, i.e., the higher the vehicle speed, the greater the line pressure value. Specifically, the relationship between the vehicle speed and the line pressure value may be a non-linear positive correlation, and of course, may also be a linear positive correlation. The first preset mode can be preset in advance, for example, the relationship between the vehicle speed and the line pressure value is calculated in the early stage through long-term experience, repeated experiments, simulation and the like, so that different speed values in the speed increasing stage and the speed decreasing stage correspond to the corresponding line pressure values to obtain stable calendering parameters. The vehicle speed value and the line pressure value that can be obtained in advance are written into the control system 10, for example, by programming a PLC.

When the vehicle speed is in the speed increasing and decreasing stage, the control system 10 obtains the line pressure value corresponding to the current vehicle speed according to the first preset mode, and further controls the pressure providing mechanism 40 to apply the pressure corresponding to the obtained line pressure value to the calender roll group 30, so that the calendering parameters of the paper are in the first preset range. The ramp-up and ramp-down phases may include a ramp-up phase and a ramp-down phase.

The super calender is a kind of calendering equipment in the field of paper making, and is suitable for calendering coated paper, writing paper, offset printing paper, etc. The supercalender in one embodiment of the present application is calendering coated paper. In other embodiments, coated paper, writing paper, or the like may be calendered, and the choice of paper type is not limited herein. In an embodiment of the present application, the calendering parameters comprise the thickness value and/or the gloss value of the paper after calendering. In the examples of the present application, the calendering parameter is one of the values comprising thickness and gloss. In other embodiments, the calendering parameters may also include both the thickness value and the gloss value, so that the gloss value of the corresponding paper grade after calendering is satisfactory at the same time as the thickness value.

Specifically, a target thickness value and/or a target gloss value may be preset. For calendering parameters including thickness values, the first predetermined range is a range defined between values before and after a target thickness value, for example a target thickness value of 5mm, which may be [5-2,5+3 ]. For calendering parameters including gloss values, the first predetermined range is a range defined between values before and after a target gloss value, for example a target gloss value of 50GU, and the first predetermined range may be [50-9,50+15 ]. For calendering parameters comprising thickness value and gloss value, the first predetermined range may comprise a range defined between values before and after the target thickness value and a range defined between values before and after the target gloss value, the thickness value and the gloss value of the paper sheet being required to simultaneously satisfy the respective ranges. Of course, the calendering parameters can also be characteristic values calculated based on the thickness value and the gloss value, and the characteristic values are obtained by performing corresponding operations, such as weighted average, on the thickness value and the gloss value. The first preset range may be a range defined between values before and after the characterization value calculated based on the target thickness value and the target gloss value. The calendering parameters of the calendered paper are in a first preset range, which can show that the calendered paper can meet corresponding requirements, for example, the thickness and/or the glossiness of the paper are always in a stable range, and the quality of the paper is stable.

The supercalender control system 10 may be a control circuit including a processor, for example, a PLC (Programmable Logic Controller) may be used. The PLC is used for controlling the driving mechanism 20 so that the driving mechanism 20 drives the roller group 30 to rotate, and further the paper can be calendered between the roller groups 30. The drive mechanism 20 can, for example, comprise a motor that can rotate the calender stack 30.

With continued reference to fig. 1, the calender roll group 30 comprises a first crown roll 310, at least one work roll 320 and a second crown roll 330 arranged side by side, and the paper can pass through the first crown roll 310, the at least one work roll 320 and the second crown roll 330 in sequence. In an embodiment of the present disclosure, the number of the working rolls 320 may be 8, and the working rolls are sequentially arranged between the first variable-height roll 310 and the second variable-height roll 330. The working roll 320 adjacent to the first variable crown roll 310, the working roll 320 spaced from the first variable crown roll 310 by two working rolls 320, the working roll 320 adjacent to the second variable crown roll 330, and the working roll 320 spaced from the second variable crown roll 330 by two working rolls 320 are provided as the metal heat roll 340, the remaining working rolls 320 are provided as the blanket roll 350, and hot water is stored in the metal heat roll 340.

Corresponding to that shown in fig. 1, roll No. 10 corresponds to first controlled crown roll 310, roll No. 9, roll No. 7, roll No. 4 and roll No. 2 correspond to metal thermo roll 340, roll No. 8, roll No. 6, roll No. 5 and roll No. 3 correspond to rubber covered roll 350, and roll No. 1 corresponds to second controlled crown roll 330. The paper passes through a No. 1 roller to a No. 10 roller in sequence for calendering. Wherein, when the paper sheet contacts with the surface of the metal hot roller 340, the glossiness of the paper sheet surface is obviously improved under the action of the temperature and the friction force of the contact surface of the metal hot roller 340. In one embodiment of the present application, the number of work rolls 320 is selected to be 8. In other embodiments, the number of the working rollers 320 may also be 10 or 12, and the number of the working rollers 320 may also be adjusted according to the selection of the paper type, and is not limited herein.

With continued reference to fig. 1, the supercalender further includes a plurality of guide rollers 360 and spreader rollers 370, the guide rollers 360 are used to guide the paper direction, so that the paper is located between the rollers of the roller set 30, a part of the guide rollers 360 are arranged at one side of the roller set 30, and another part of the guide rollers 360 are arranged at the other side of the roller set 30. A spreader roll 370 is provided at one side of the calender roll stack 30 for spreading the paper during calendering. The number of the guide rollers 360 and the spreader rollers 370 is not limited herein.

The pressure providing mechanism 40 is used to apply a corresponding pressure to the calendar stack 30 to adjust the line pressure value in the calendar stack 30. The pressure providing mechanism 40 may comprise at least one hydraulic cylinder for acting on the first crown roll 310 and/or the second crown roll 330 and thereby adjusting the linear pressure values of the paper between the first crown roll 310, the plurality of work rolls 320 and the second crown roll 330. In an embodiment of the present application, the number of the hydraulic cylinders is 2, and the hydraulic cylinders are respectively disposed on two opposite sides of the first variable crown roll 310. In other embodiments, the hydraulic cylinders may be disposed at other positions, for example, at two ends of the first variable-height roller 310 opposite to the axial direction, as long as the hydraulic cylinders act on the first variable-height roller 310 and can adjust the linear pressure value of the paper among the first variable-height roller 310, the work roller 320, and the second variable-height roller 330, and the specific position of the first variable-height roller 310 is not limited herein.

The inventor of the application finds that the change of the vehicle speed of the supercalender during working can go through a speed-up stage and a speed-down stage, the paper is guided from the speed-up stage to carry out calendering operation, and the paper is in a calendered state along with the reduction of the vehicle speed in the speed-down stage. At present, the speed of the supercalender can reach 1500m/min at most, the speed of the acceleration stage needs 150 seconds from 0 to 1500m/min, the deceleration stage is opposite to the acceleration stage, namely, the speed of the supercalender is always in the change process in the acceleration and deceleration stage. The corresponding speed of the supercalender in the speed-up stage or the speed-down stage is to the set speed value according to a certain acceleration or deceleration, the speed is always in the changing process, the linear pressure value in the calender roll group 30 is difficult to adjust due to the change of the speed of the supercalender, and the manual adjustment mode is usually adopted at present, so that the paper quality is difficult to ensure. In an embodiment of the present application, the control system 10 of the supercalender sets a first preset mode, when the supercalender is in the speed-up/down stage, the control system 10 obtains a line pressure value corresponding to the current vehicle speed according to the first preset mode, and then controls the pressure providing mechanism 40 to apply a pressure corresponding to the obtained line pressure value to the calender roll group 30, so that the line pressure value corresponding to the current vehicle speed is automatically adjusted by using the first preset mode through the control system 10, and compared with a manual mode, the adjustment efficiency is higher and more accurate, and manual misoperation can be reduced, so that the calendering parameters of the calendered paper corresponding to the speed-up/down stage are within a first preset range, and the requirement of the paper quality can be met. The preset speed of a motor vehicle corresponds with the line pressure value, then can correspond adjustment line pressure value according to the speed of a motor vehicle, and then make the calendering parameter that the paper after the calendering corresponds alright remain throughout in first preset range betterly, so set up, supercalender does not even be in the speed change's speed raising stage, the calendering parameter also is in comparatively stable state, so alright make the paper also can obtain stable calendering parameter to the condition that the speed of a motor vehicle changes in speed raising stage, improve the calendering quality and the stability of paper, reduce the condition that the paper after the supercalender is calendered at speed raising stage needs the reburning because the calendering parameter is unstable.

The supercalender further comprises a detection mechanism 60, which detection mechanism 60 can be coupled to the control system 10 for detecting calendering parameters of the paper. Specifically, when the supercalender is in an up-down stage, the detection mechanism 60 can send the detected calendering parameters to the control system 10. The control system 10 may also acquire a line pressure value corresponding to the current vehicle speed, and control the pressure supply mechanism 40 to apply a pressure corresponding to the acquired line pressure value to the calender roll group 30. The pressure providing mechanism 40 acts on the roller group 30 and can adjust the distance between each roller in the roller group 30, so that the pressure applied to the paper by the adjacent rollers changes, namely the line pressure value changes. The line pressure in the calender roll stack 30 can be controlled by controlling the pressure providing mechanism 40. And then the linear pressure value corresponding to the current running vehicle speed can be obtained, so that the calendering parameters of the paper are in a first preset range.

The control system 10 is further provided with a second preset mode for characterizing the relationship between the line pressure value and the difference between the calendering parameters and the first target parameters. The second preset mode may be preset in advance, for example, the relationship between the difference between the calendering parameters and the first target parameters and the line pressure value may be calculated in a manner of long-term experience in the early stage, repeated experiments, simulation, and the like, and then the calculated relationship is written into the control system 10, for example, the calculated relationship is obtained by programming a PLC.

When the vehicle speed is in the speed stabilizing stage, the control system 10 obtains a line pressure value corresponding to the difference value between the current calendering parameter and the first target parameter according to a second preset mode, and further controls the pressure providing mechanism 40 to apply a pressure corresponding to the obtained line pressure value to the calendering roller group 30, so that the difference value between the calendering parameter of the paper and the first target parameter is in a second preset range. For calendering parameters including a thickness value, the first target parameter may include a target thickness value, and assuming that the target thickness value is 3mm and the thickness value is 4mm, the difference between the thickness value and the target thickness value is 1mm, and assuming that the line pressure value corresponding to 1mm is 500N, the control system 10 controls the pressure providing mechanism 40 to apply a pressure corresponding to the line pressure value to the calender stack 30, for example, the pressure providing mechanism 40 applies a thickness value of 3mm corresponding to 3000N. Assuming that the second preset range is [ -2,2] and the pressure providing mechanism 40 is configured to keep the difference between the thickness value and the target thickness value within [ -2,2], it is possible to decrease 1000N on the basis of 3000N to increase 1000N. For example, when the line pressure value is 4200N and the difference between the corresponding thickness value and the target thickness value is not within [ -2,2], it is necessary to reduce to [2000,4000] so that the difference between the thickness value and the target thickness value is not within [ -2,2 ]. Assuming that the second predetermined range is [ -0.5,0.5], the control system 10 controls the pressure providing mechanism 40 to decrease 250N to increase 250N on the basis of 3000N, that is, to be in [2750,3250 ]. For the gloss, assuming that the target gloss value is 50GU and the measured gloss value is 60GU, the measured gloss value is different from the target gloss value by 10GU and the line pressure value corresponding to 10GU is 100N, at which time the control system 10 controls the pressure supply mechanism 40 to apply a pressure corresponding to the line pressure value to the calender roll group, for example, 50GU when the pressure supply mechanism 40 applies 2000N. Assuming that the second preset range is [ -20,20], the control system 10 controls the pressure providing mechanism 40 to decrease the range of 200N to increase the range of 200N, that is, to [1800,2200], so that the difference between the gloss value and the target gloss value can be maintained within [ -20,20 ].

When the speed of a vehicle is in a steady-speed stage, because systematic errors occurring in the operation of the calender roll group 30 or errors occurring in other parts of the supercalender can cause the quality fluctuation of paper in the production process, the fluctuation of the quality of the paper can further cause the calendering parameters of the paper to change in the steady-speed stage, and further deviate from the preset calendering parameters. The control system 10 sets a second preset mode, and when the difference between the current calendering parameter and the first target parameter exceeds a second preset range, the second preset mode obtains the line pressure value corresponding to the difference between the current calendering parameter and the first target parameter, and further applies a pressure corresponding to the obtained line pressure value to the calendering roller group 30 by controlling the pressure providing mechanism 40, so that the difference between the calendering parameter of the paper and the first preset target parameter is within the second preset range.

In the process of calendering the paper, the length of the paper along the axial direction of the roller set 30 is constant, but along the direction perpendicular to the axial direction of the roller set 30, that is, corresponding to the direction of the calendering flow of the paper, the thickness or quality of the paper per unit distance often has a certain difference, because of the variation of the thickness of the paper, the linear pressure value applied to the paper by the roller set 30 during the calendering process of the paper per unit distance is also different. For example, if the thickness of the current paper at the unit distance is too thick or too thin, the difference between the thickness or the gloss of the calendered paper and the first target parameter is too high, and the line pressure applied to the corresponding current paper is too large or too small, if the difference between the current thickness or the gloss and the first target parameter is back to the second preset range, the pressure providing mechanism 40 is required to adjust the line pressure applied to the paper by the calender roll set 30, and the adjustment of the line pressure at this time is to adjust the line pressure corresponding to the change of the thickness of the paper at the unit distance, that is, to the case that the thickness of the corresponding paper is too thick or too thin, so as to increase or decrease the line pressure, and make the difference between the thickness or the gloss of the calendered paper and the first target parameter back to the second preset range.

Referring to fig. 2 and 3, fig. 3 is a schematic diagram illustrating a variation state of a line pressure value and a vehicle speed according to an embodiment of the present application. In an embodiment of the supercalender of the present application, the supercalender further comprises a man-machine circuit 50 connected to the control system 10, the man-machine circuit 50 being configured to display calendering parameters and to display images corresponding to the first preset mode and the second preset mode, respectively. The man-machine circuit 50 includes a control panel for displaying the calendering parameters and the images corresponding to the first preset mode and the second preset mode, and a control circuit for performing command control on the supercalender, such as turning on or off the power supply, selecting the corresponding paper type, selecting the first preset mode or the second preset mode, and the like.

The image corresponding to the first preset mode comprises a first curve segment 510 displayed in an acceleration stage in the acceleration and deceleration stage and a second curve segment 520 displayed in a deceleration stage in the acceleration and deceleration stage; the image corresponding to the second preset mode is displayed as a third curve segment 530, and the third curve segment 530 is connected between the first curve segment 510 and the second curve segment 520, and further displayed as a same curve. It will be appreciated that different paper grades correspond to different first curve segments 510, second curve segments 520, and third curve segments 530 during the ramp-up, ramp-down, and ramp-down phases. Referring to fig. 3 and 4, when the vehicle speed is different, the corresponding line pressure value corresponds to the vehicle speed. It can be understood that, in the same paper type, a calendering parameter is set, the speed-up stage can be divided into a plurality of speed-up processes, for example, 10 percentage values of the set vehicle speed are shown graphically, corresponding to 10 different speed-up processes, the average value of the vehicle speed in each speed-up process is selected as a target value in the different speed-up processes, a plurality of different line pressure values can be input into a control panel for one target value until the obtained calendering parameter corresponding to the line pressure value is the same as the set calendering parameter, and the target value corresponding to the line pressure value is recorded. By repeating the above steps, more line pressure values corresponding to the target value can be obtained, and a mathematical model can be established at multiple points to obtain the first curve segment 510. The second curve segment 520 is obtained in the same manner as the first curve segment 510, and will not be described herein. It will be appreciated that the third curve segment 530 corresponds to the vehicle speed having reached the final vehicle speed value, the final vehicle speed value and the line pressure value, and corresponds to point P in the graph, i.e., the first curve segment 510, the second curve segment 520, and the third curve segment 530 may be a continuous curve. However, the line pressure value fluctuates to some extent at a plurality of points P in the figure, that is, at a stable vehicle speed, and the plurality of points P fluctuate up and down in the axial direction of the line pressure value in the figure. In the speed stabilization stage, the thickness value or the gloss value after calendering is also deviated due to the gram weight of the paper, and the line pressure value is required to be adjusted, so that the line pressure value is also floated. However, when the vehicle speed is in the steady-speed stage, if there is no reason for the paper itself, only one point P is shown in the figure, and the first curve segment 510, the second curve segment 520 and the third curve segment 530 are continuous curves.

In an embodiment of the supercalender of the present application, the detecting mechanism 60 is further configured to detect the calendered paper along the axial direction of the calender roll group 30 and obtain a plurality of calendering parameters of the paper distributed along the axial direction of the calender roll group 30. The control system 10 is used to calculate a plurality of calendering parameters of the sheet distributed along the axial direction of the calender roll group 30 to obtain the calendering uniformity. The control system 10 is preset with a third preset mode, where the third preset mode is used to represent a relationship between the calendering uniformity and the line pressure value, and the third preset mode may be preset in advance, for example, the calendering uniformity required by a user, and then is written into the control system 10, for example, the third preset mode is obtained by programming a PLC. The control system 10 is configured to obtain a line pressure value corresponding to the calendering uniformity according to a third preset mode, and control the calender roll group 30 to adjust a corresponding position along the axial direction of the calender roll group 30, so as to form a pressure corresponding to the obtained line pressure value at a corresponding position between the calender roll groups 30, thereby enabling the calendering uniformity to be within a third preset range. In particular, at least part of the positions in the axial direction in the calender roll stack 30 can be adjusted, for example the distance between the part positions of two oppositely situated rolls can be adjusted, so that the part positions of the two rolls can be brought closer to each other or further away from each other, so that the line pressure which is formed between the two rolls can be adjusted. At this time, the roll is a controlled crown roll, and the controlled crown roll includes a plurality of pressure adjusting regions, so that the distance between the controlled crown roll and the adjacent roll can be adjusted, and further the linear pressure between the controlled crown roll and the adjacent roll can be adjusted, and the specific structure refers to the detailed description of the first controlled crown roll 310 below.

It will be appreciated that the sheet thickness per unit area in the axial direction of the stack 30 is also different, and the detection means 60 is arranged to detect the sheet in the axial direction of the stack 30 and to obtain a plurality of calendering parameters distributed in the axial direction of the stack 30. In one embodiment of the present application, the detecting mechanism 60 includes a scanning unit, which reciprocates along the axial direction of the calender roll group 30, and the detected data can be transmitted to the human-machine circuit 50 in real time and then displayed on the control panel.

The calendering uniformity is the difference between each of a plurality of calendering parameters of the paper and a second target parameter; alternatively, the control system 10 is used to calculate a plurality of calendering parameters for the sheet along the axial direction of the calender roll stack 30 to obtain a 2sigma value, and the calendering uniformity is the difference between the 2sigma value and the 2sigma target value. In an embodiment of the present application, the second target parameter may be a thickness value and/or a gloss value, and the thickness value and/or the gloss value scanned by the scanning unit is compared with the second target parameter to obtain a difference therebetween. In other embodiments, the calendering uniformity may also be a 2sigma value calculated from a plurality of calendering parameters distributed along the axial direction of the calendering roller group 30, that is, a mean value a of the calendering parameters scanned by the scanning unit is calculated, and then a standard deviation B of the plurality of calendering parameters is calculated. The probability of a 2sigma value, i.e., a numerical distribution over (A-2B, A +2B), is 0.9544. The lower the corresponding standard deviation B, the higher the uniformity of the resulting calendering parameters.

Referring to fig. 4, fig. 4 is a schematic view showing a partial structure of a first crown roll of the supercalender shown in fig. 1. The principle of the second crown roll 330 is identical to the first crown roll 310, so that no further illustration of the second crown roll 330 is made here. Wherein the first variable-crown roll 310 has a plurality of first pressure adjustment zones a distributed along an axial direction thereof, and the control system 10 is configured to adjust a pressure between a corresponding position corresponding to the first pressure adjustment zone and the adjacent work roll 320. When the difference between the calendering parameters of the paper in the axial direction of the calendering roller group 30 and the second target parameters is too large, the corresponding first pressure adjusting area a can be adjusted, so that the calendering uniformity is in a third preset range.

The first crown roll 310 and the second crown roll 330 are composed of a cylinder 311, a mandrel 312, a piston 313 supported on the mandrel, a sealing device 314, and the like, and specifically, refer to a partial structural schematic diagram of the first crown roll 310 of fig. 4. The cylinder 311 is supported on an array of pistons 313 of the mandrel 312 by hydrostatic pressure, the lower part of the pistons 313 is connected with a hydraulic system (not shown) outside the cylinder, the upper surface and the lower surface of the pistons 313 are communicated through capillary holes, hydraulic oil which passes through the capillary holes leaks out from the position between the surface of the piston 313 and the inner wall of the cylinder 311, so as to obtain a pressure balanced and stable oil film between the upper surface and the lower surface of the piston 313 to bear the pressure between the piston 313 and the cylinder 311, the first controllable medium-high roll 310 and the second controllable medium-high roll 330 can comprise a plurality of pressure zones as shown in the figure, each pressure zone can comprise one or a plurality of pistons 313, and the distance between the position of the corresponding cylinder 311 and the adjacent working roll 320 can be adjusted by adjusting the oil supply pressure at different parts of the pistons 313, so as to adjust the thickness uniformity of paper along the axial direction of the first controllable medium-high roll 310 or the second controllable medium-high roll 330.

The calender roll group 30 comprises a second controllable crown roll 330 which is arranged at one side of at least one working roll 320 far away from the first controllable crown roll 310, the paper is sequentially threaded between the second controllable crown roll 330 and the working roll 320 and between the first controllable crown roll 310 and the working roll 320, and the detection mechanism 60 is used for detecting the calendering parameters of the calendered paper led out between the first controllable crown roll 310 and the working roll 320; the second variable crown roll 330 has a plurality of second pressure adjustment zones distributed along an axial direction thereof, and the control system 10 is further configured to adjust the pressure between the respective positions corresponding to the second pressure adjustment zones and the adjacent work rolls 320.

Referring to fig. 5, fig. 5 is a flow chart of the linear pressure control of an embodiment of the supercalender of the present application. Another embodiment of the present application further provides a line pressure control method applied to the supercalender, including:

s110: judging whether the vehicle speed is in a speed increasing and decreasing stage;

generally, a supercalender comprises a speed-up stage, a speed-stabilizing stage and a speed-reducing stage, wherein the speed of the speed-up stage and the speed-reducing stage is constantly in change, and a control system acquires a current speed value and compares the current speed value with a preset speed value in the speed-stabilizing stage to obtain whether the current speed is in the speed-up and speed-reducing stage.

S120: if so, acquiring the current vehicle speed, and acquiring a linear pressure value corresponding to the current vehicle speed according to a first preset mode;

when the speed of a motor vehicle is in the stage of speeding up and down, control system obtains the line pressure value that current speed of a motor vehicle corresponds according to first preset mode, and then control pressure provides the mechanism and applys the pressure that corresponds with the line pressure value to the press polish roller group to make the press polish parameter of paper be in first preset within range. The speed increasing stage is displayed as a first curve section on the man-machine circuit, the speed reducing stage is displayed as a second curve section on the man-machine circuit, namely the regulation and control of the linear pressure value and the vehicle speed in the speed increasing stage can be carried out according to the first curve section, and the regulation and control of the linear pressure value and the vehicle speed in the speed reducing stage can be carried out according to the second curve section. So set up, be in the speed-up stage or the speed-down stage at the supercalender, also can make the calendering parameter that the paper reachs after the calendering be in first preset within range under the condition that the speed is constantly changed.

S130: and controlling the pressure providing mechanism to apply pressure corresponding to the acquired line pressure value to the roller group so that the calendering parameter of the paper is in a first preset range.

The control system is coupled with the pressure providing mechanism, when the speed changes in the speed increasing and reducing stage, each speed value corresponds to a corresponding linear pressure value on the first curve section and the second curve section, and then the control system can control the pressure providing mechanism to apply pressure corresponding to the obtained linear pressure value on the calendering roller group, so that the calendering parameters of the paper can be in a first preset range.

In another embodiment, the method further comprises:

s140: judging whether the vehicle speed is in a stable speed stage;

s150: if so, acquiring a line pressure value corresponding to the difference value between the current piezooptical parameter and the first target parameter;

s160: and controlling the pressure providing mechanism to apply pressure corresponding to the acquired line pressure value to the roller group so that the difference value between the calendering parameter of the paper and the first target parameter is in a second preset range.

When the speed of a vehicle is in steady speed stage, the axial direction of the press roller group is the first direction, the direction vertical to the axial direction of the press roller group is the second direction, and the second direction corresponds to the press rolling flow direction of the paper. The thickness of the paper of unit distance in the second direction is inconsistent before calendering, and then leads to different paper thickness all carry out the calendering according to the line pressure value that the steady speed stage corresponds, and the calendering parameter of the paper that so reachs also can have the difference. Therefore, the control system controls the pressure providing mechanism to apply pressure corresponding to the acquired line pressure value to the calendering roller group by acquiring the line pressure value corresponding to the difference value of the current calendering parameter and the first target parameter, so that the difference value of the calendering parameter of the paper and the first target parameter can be in a second preset range.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.