A coating pressure screen slag control system for use in the production of coated white paper

Abstract

The utility model discloses a kind of coating pressure screen slag discharge control systems for coating white cardboard production in middle, including coating feeding groove and coating head, and coating pressure screen is connected between coating feeding groove and coating head by pipeline;Coating pressure screen bottom is connected with discharge pipeline, and discharge pipeline branch is connected with flushing pipeline;Second automatic stop valve for controlling the screen residue of stored coating is arranged in the lower side upper portion of flushing pipeline located branch on discharge pipeline;Discharge pipeline end is further provided with third automatic stop valve for controlling pipeline on-off again, for the screen residue of stored coating in discharge pipeline is preliminarily pre-stored after second automatic stop valve opens and is discharged;Only need to close second automatic stop valve when discharging, open third automatic stop valve, in the normal operation condition without affecting coating pressure screen, the screen residue stored in the corresponding pipeline of discharge pipeline between second automatic stop valve and third automatic stop valve can be discharged, effectively improve the quality of coating processing and the stability of papermaking.

Description

Technical Field

[0001] This utility model relates to the field of slag discharge control technology for cardboard, and in particular to a slag discharge control system for a coating pressure screen used in the production of coated white cardboard. Background Technology

[0002] The coating of coated white cardboard generally consists of two layers (bottom layer + top layer) or three layers (bottom layer + backing layer + top layer). The coating material is mainly composed of calcium carbonate, kaolin, latex, chemical additives and other components of various particle sizes. Impurities in the coating material need to be screened out by a pressure screen to avoid scratching or contaminating the paper coating.

[0003] The main function of a coating pressure screen is to remove impurities and large particles from coatings, ensuring the purity and uniformity of the coating. If these impurities enter the feeding trough, they can cause coating scratches, paper surface contamination, indentations, and other paper defects, and even damage the equipment. During operation, the coating passes through the pressure screen; fine coating particles can pass through the screen holes to the next process, while larger particles and impurities are blocked in the pulp zone, thus achieving filtration. Therefore, coating pressure screens play a crucial role in coating production and coating processes, ensuring coating quality and stable, efficient production.

[0004] However, the screen residue from the coating pressure screen accumulates continuously within the screen, and excessive residue can negatively impact its performance. Therefore, regular cleaning and slag removal are necessary. In existing technology, during cleaning, the coating pressure screen must be stopped, the automatic valve opened to empty it, and then the bypass valve opened. At this point, the coating supplied from the coating feed trough is sent to the bypass pipe next to the coating pressure screen, allowing unfiltered coating to directly pass through the bypass pipe and enter the coating head of the coating machine. Since the coating is not filtered by the pressure screen, impurities in the coating will directly reach the coating head and be applied to the paper, leading to defects such as scraper marks, dirt, and embossing, inevitably affecting the quality of the finished paper.

[0005] Therefore, there is an urgent need to improve the existing coating pressure screen slag discharge system to avoid the coating pressure screen stopping work and affecting the paper quality during slag discharge and cleaning. Utility Model Content

[0006] This invention provides a coating pressure screen slag discharge control system for coated white cardboard production, which effectively solves the quality fluctuation problem caused by the intermittent working mode of the coating pressure screen. The coating pressure screen can work continuously during slag discharge and cleaning, effectively improving the quality of coating processing and the stability of paper, and effectively improving the production efficiency of coating.

[0007] The technical solution adopted by this utility model to solve its technical problem is: A coating pressure screen slag discharge control system for coating white cardboard production includes a coating feeding trough and a coating head, wherein the coating feeding trough is used to receive coating supplied by a storage tank. The coating feeding tank and the coating head are connected by a pipeline to a coating pressure screen that filters the supplied coating. The bottom of the coating pressure screen is connected to a slag discharge pipe. Near the slag discharge port at the bottom of the coating pressure screen, a branch of the slag discharge pipe is connected to a flushing pipe that sprays high-pressure cleaning water into the interior of the coating pressure screen. A first automatic shut-off valve for controlling the opening and closing of the flushing pipe is installed on the flushing pipe. A second automatic shut-off valve is installed on the upper part of the flushing pipeline on the branch of the slag discharge pipeline to control the opening and closing of the pipeline and to control the discharge of the coating slag stored in the coating pressure screen. The end of the slag discharge pipeline below the second automatic shut-off valve is also provided with a third automatic shut-off valve for controlling the pipeline opening and closing again, and for pre-storing the paint slag discharged after the second automatic shut-off valve is opened in the slag discharge pipeline. The slag discharge pipe below the second automatic shut-off valve is also connected by a bypass to a clean water pipe that is used to flush out the pre-stored paint slag in the slag discharge pipe after the second automatic shut-off valve is closed and the third automatic shut-off valve is opened.

[0008] Preferably, a feed branch pipe for supplying paint directly into the coating head is also connected in parallel on the feed pipe between the paint feeding trough and the feed inlet of the paint pressure screen. The feed branch pipe is connected in parallel to the screen material conveying pipe connected to the discharge port of the paint pressure screen. The feeding pipeline is connected to a fourth automatic shut-off valve for controlling the on / off of the pipeline, the feeding branch pipeline is connected to a fifth automatic shut-off valve for controlling the on / off of the pipeline, and the inlet and outlet of the coating pressure screen are respectively equipped with an automatic feed shut-off valve and an automatic discharge shut-off valve for controlling the on / off of the feed and discharge. The screen conveying pipeline below the coating head is also connected to a sixth automatic shut-off valve to control the on / off state of the pipeline.

[0009] Preferably, the screening conveying pipeline below the sixth automatic shut-off valve is further branched with a paint recovery pipeline for returning uncoated paint from the coating head and the lower pipeline to the paint feeding tank when the machine stops.

[0010] Preferably, the coating pressure screen is connected to a return pipe that serves to exhaust air.

[0011] Preferably, the coating head is further connected to a secondary recovery pipeline that filters the remaining coating material again through a filter and then returns it to the coating material feeding tank.

[0012] Preferably, the coating pressure screen includes a vertically arranged cylindrical screen frame and a screen drum. The screen drum is coaxially fitted into the center of the screen frame. The upper end of the screen frame is provided with a feed inlet extending into the screen drum. The lower end of the screen frame is provided with a discharge outlet extending from the gap between the screen drum and the screen frame for discharging the screened coating. A flushing water pipe connected to the bottom flushing pipe and rotating under the drive of a motor is inserted into the center of the screen drum. A scraper with brush-shaped PTFE is also connected to the side of the flushing water pipe for scraping the inner wall of the screen drum. A slag discharge pipe connected to the bottom of the screen drum is connected to the slag discharge pipe.

[0013] The beneficial effects of this utility model are: During slag discharge, simply close the second automatic shut-off valve and open the third automatic shut-off valve. Without affecting the normal coating screening of the coating pressure screen, i.e. without stopping the machine, the slag stored in the corresponding pipe of the slag discharge pipeline between the second and third automatic shut-off valves can be discharged, effectively improving the quality of coating processing and the stability of paper, and effectively improving the production efficiency of coating.

[0014] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0015] Figure 1 This is a schematic diagram illustrating the working principle of this utility model; Figure 2 This is a partial cross-sectional view of the coating pressure screen in this utility model. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. Terms such as "center," "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0018] Furthermore, if the terms "first" or "second" are used only to distinguish technical features, they should not be interpreted as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or implicitly indicating the order of the technical features indicated.

[0019] Furthermore, in the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installing," and "connecting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be reasonably determined in conjunction with the specific content of the technical solution.

[0020] A coating pressure screen slag discharge control system for use in the production of coated white cardboard, such as Figure 1 As shown, the system includes a paint feeding tank 1 and a coating head 2. The paint feeding tank 1 receives paint supplied from the storage tank. A paint pressure screen 3, which filters the supplied paint, is connected to the paint feeding tank 1 and the coating head 2 via a pipeline. A slag discharge pipe 4 is connected to the bottom of the paint pressure screen 3. A branch of the slag discharge pipe 4 near the slag discharge port at the bottom of the paint pressure screen 3 is connected to a flushing pipe 5, which sprays high-pressure cleaning water into the paint pressure screen 3. A first automatic shut-off valve 6 is installed on the flushing pipe 5 to control the on / off state of the pipe. A control valve is installed on the upper part of the flushing pipe 5 below the branch of the slag discharge pipe 4. The pipeline is open and closed by a second automatic shut-off valve 7, which controls the discharge of coating slag stored in the coating pressure screen 3. A third automatic shut-off valve 8 is also provided at the end of the slag discharge pipeline 4 below the second automatic shut-off valve 7, which controls the pipeline opening and closing again, and is used to pre-store the coating slag discharged after the second automatic shut-off valve 7 is opened in the slag discharge pipeline 4. A bypass connection is also provided on the slag discharge pipeline 4 below the second automatic shut-off valve 7, which is used to flush and discharge the coating slag pre-stored in the slag discharge pipeline 4 after the second automatic shut-off valve 7 is closed and the third automatic shut-off valve 8 is opened.

[0021] like Figure 2As shown, the coating pressure screen 3 includes a vertically arranged cylindrical screen frame 30 and a screen drum 31. The screen drum 31 is coaxially fitted into the center of the screen frame 30. The upper end of the screen frame 30 is provided with a feed inlet 32 ​​that extends into the screen drum 31. The lower end of the screen frame 30 is provided with a discharge outlet 33 that extends out from the gap between the screen drum 31 and the screen frame 30 for discharging the screened coating. A flushing water pipe 34, which is connected to the bottom flushing pipe 5 and rotates under the drive of a motor, is inserted into the center of the screen drum 31. A scraper 35 with brush-shaped PTFE is also connected to the side of the flushing water pipe 34 to scrape the inner wall of the screen drum 31. A slag discharge pipe 36, which is connected to the slag discharge pipe 4, is also connected to the bottom of the screen drum 31.

[0022] During slag discharge, simply close the second automatic shut-off valve 7 and open the third automatic shut-off valve 8. Without stopping the coating pressure screen 3, the slag stored in the corresponding pipe of the slag discharge pipeline 4 between the second automatic shut-off valve 7 and the third automatic shut-off valve 8 will be discharged, effectively improving the quality of coating processing and the stability of paper production, and effectively improving the production efficiency of coating.

[0023] like Figure 1 As shown, a feed branch pipe 11 for directly supplying paint into the coating head 2 is also connected in parallel to the feed pipe 10 between the paint feeding tank 1 and the feed inlet 32 ​​of the paint pressure screen 3. The feed branch pipe 11 is connected in parallel to the screen material conveying pipe 12 connected to the discharge port 33 of the paint pressure screen 3. The feed pipe 10 is connected to a fourth automatic shut-off valve 13 for controlling the on / off of the pipe, and the feed branch pipe 11 is connected to a fifth automatic shut-off valve 14 for controlling the on / off of the pipe. The feed inlet 32 ​​and the discharge port 33 of the paint pressure screen 3 are respectively equipped with an automatic feed shut-off valve 15 and an automatic discharge shut-off valve 16 for controlling the on / off of the material. In this way, by switching the fourth automatic shut-off valve 13 and the fifth automatic shut-off valve 14, the paint in the paint feeding tank 1 that does not need to be filtered by the paint pressure screen 3 can be directly supplied to the coating head 2 as needed.

[0024] Continue as Figure 1 As shown, a sixth automatic shut-off valve 17 for controlling the on / off state of the pipeline is also connected to the screening conveying pipeline 12 below the coating head 2. A branch of the screening conveying pipeline 12 below the sixth automatic shut-off valve 17 is also connected to a paint recovery pipeline 18 for returning uncoated paint in the coating head 2 and the lower pipeline to the paint feeding tank 1 when the machine stops. The paint recovery pipeline 18 promptly recovers the uncoated paint in the coating head 2 and the lower pipeline when the machine stops. At the same time, a return pipeline 19 for exhaust function is also connected to the paint pressure screen 3 to realize multiple circulation and filtration of paint in the paint feeding tank 1. The coating head 2 is also connected to a secondary recovery pipeline 21 for filtering the remaining paint after coating through the filter 20 and then returning it to the paint feeding tank 1, effectively saving paint and reducing production costs.

[0025] The above-described embodiments are merely preferred embodiments of this utility model and are not intended to limit the scope of implementation of this utility model. All equivalent changes made in accordance with the shape, structure and principle of this utility model should be covered within the protection scope of this utility model.

Claims

1. A coating pressure screen slag discharge control system for use in the production of coated white cardboard, characterized in that, It includes a paint feeding tank and a coating head, wherein the paint feeding tank is used to receive paint supplied by the storage tank; The coating feeding tank and the coating head are connected by a pipeline to a coating pressure screen that filters the supplied coating. The bottom of the coating pressure screen is connected to a slag discharge pipe. Near the slag discharge port at the bottom of the coating pressure screen, a branch of the slag discharge pipe is connected to a flushing pipe that sprays high-pressure cleaning water into the interior of the coating pressure screen. A first automatic shut-off valve for controlling the opening and closing of the flushing pipe is installed on the flushing pipe. A second automatic shut-off valve is installed on the upper part of the flushing pipeline on the branch of the slag discharge pipeline to control the opening and closing of the pipeline and to control the discharge of the coating slag stored in the coating pressure screen. The end of the slag discharge pipeline below the second automatic shut-off valve is also provided with a third automatic shut-off valve for controlling the pipeline opening and closing again, and for pre-storing the paint slag discharged after the second automatic shut-off valve is opened in the slag discharge pipeline. The slag discharge pipe below the second automatic shut-off valve is also connected by a bypass to a clean water pipe that is used to flush out the pre-stored paint slag in the slag discharge pipe after the second automatic shut-off valve is closed and the third automatic shut-off valve is opened.

2. The coating pressure screen slag discharge control system for coated white cardboard production according to claim 1, characterized in that: The feeding pipeline between the coating feeding trough and the feeding port of the coating pressure screen is also connected in parallel to a feeding branch pipeline for supplying coating directly into the coating head. The feeding branch pipeline is connected in parallel to the screen material conveying pipeline connected to the discharge port of the coating pressure screen. The feeding pipeline is connected to a fourth automatic shut-off valve for controlling the on / off of the pipeline, the feeding branch pipeline is connected to a fifth automatic shut-off valve for controlling the on / off of the pipeline, and the inlet and outlet of the coating pressure screen are respectively equipped with an automatic feed shut-off valve and an automatic discharge shut-off valve for controlling the on / off of the feed and discharge. The screen conveying pipeline below the coating head is also connected to a sixth automatic shut-off valve to control the on / off state of the pipeline.

3. A coating pressure screen slag discharge control system for coated white cardboard production according to claim 2, characterized in that: The screening conveying pipeline below the sixth automatic shut-off valve is also branched into a paint recovery pipeline for returning uncoated paint from the coating head and the lower pipeline to the paint feeding tank when the machine stops.

4. A coating pressure screen slag discharge control system for coated white cardboard production according to claim 1, characterized in that: The coating pressure screen is connected to a return pipe that serves to exhaust air.

5. A coating pressure screen slag discharge control system for coated white cardboard production according to claim 1, characterized in that: The coating head is also connected to a secondary recovery pipeline that filters the remaining coating material again through a filter and then returns it to the coating material feeding tank.

6. A coating pressure screen slag discharge control system for coated white cardboard production according to claim 1, characterized in that: The coating pressure screen includes a vertically arranged cylindrical screen frame and a screen drum. The screen drum is coaxially fitted into the center of the screen frame. The upper end of the screen frame is provided with a feed port extending into the screen drum. The lower end of the screen frame is provided with a discharge port extending from the gap between the screen drum and the screen frame for discharging the screened coating. A flushing water pipe connected to the bottom flushing pipe and rotating under the drive of a motor is inserted into the center of the screen drum. A scraper with brush-shaped PTFE is also connected to the side of the flushing water pipe for scraping the inner wall of the screen drum. A slag discharge pipe connected to the bottom of the screen drum is connected to the slag discharge pipe.

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