Filter screen self-cleaning system and hot air system of paper machine

Abstract

The utility model provides a filter screen self-cleaning system and a hot air system of a paper machine, which comprise a central control unit, a wind pressure monitoring unit, a cleaning unit and a moving unit, the wind pressure monitoring unit is used for receiving wind pressure on two sides of a filter screen and transmitting the wind pressure to the central control unit; the central control unit judges the cleaning time of the filter screen according to the detected air pressure information, the cleaning unit can automatically clean the surface of the filter screen, and the moving unit can automatically control the filter screen to move to a cleaning area. Through combination of intelligent pressure difference control and automatic cleaning, capacity consumption in manual cleaning is reduced, efficiency, quality and safety in paper machine production are improved, and the paper machine has remarkable market application value. The hot air system comprising the filter screen self-cleaning system can automatically complete filtering work in the airflow circulation process and has the advantages of being high in automation degree and good in cleaning effect.

Description

TECHNICAL FIELD

[0001] The utility model relates to a filter screen cleaning structure, specifically a filter screen self-cleaning system and a hot air system of paper machine. BACKGROUND

[0002] In the production process of toilet paper, the paper pulp material is preliminarily formed through the head box injection, the felt cloth and the forming screen, and then sequentially passes through the pressing, drying cylinder drying and shroud hot air drying processes, and finally completes the wrinkling and winding. Among them, the shroud hot air drying system as a key heat supply unit provides the main heat source for the whole drying process.

[0003] The heat exchanger is the core component of the system, and its running state directly affects the drying efficiency and the quality of the finished paper. The filter screen is provided at the fresh air inlet of the heat exchanger, and the filter screen is filled with fireproof cotton filter medium to continuously trap dust and impurities in the fresh air. After long-term use, these dust and impurities will deposit on the surface of the filter screen. If not cleaned in time, not only the heat exchange efficiency will be reduced, but also the equipment may be blocked, thereby affecting the drying effect and product quality.

[0004] In the prior art, the cleaning of the filter screen relies on manual maintenance and needs to be stopped regularly for cleaning. Manual cleaning has obvious defects: first, the efficiency of manual cleaning is low and the operation is difficult; second, the high-temperature working environment has safety hazards; and at the same time, manual cleaning cannot realize timely cleaning of the filter screen. Therefore, the filter screen cleaning structure in the prior art needs to be improved. UTILITY MODEL CONTENTS

[0005] To solve the above technical problems, the utility model provides a filter screen self-cleaning system, which comprises a filter screen movably arranged outside a ventilation opening;

[0006] A wind pressure monitoring unit is used to monitor the pressure difference information between the air inlet side and the air outlet side of the filter screen.

[0007] A cleaning unit is arranged outside the ventilation opening and cleans the surface of the filter screen when the filter screen moves.

[0008] A moving unit is arranged outside the ventilation opening and is used to control the filter screen to move to a cleaning area.

[0009] A central control unit is used to receive the pressure difference information fed back by the wind pressure monitoring unit and send a work instruction according to the pressure difference information. The cleaning unit and the moving unit are respectively provided with executable elements, which can control the cleaning unit and the moving unit to work according to the instruction sent by the central control unit.

[0010] Further, the central control unit is pre-set with pressure difference information, and when the detected pressure difference is not less than the pre-set pressure difference, a work instruction is sent.

[0011] Further, the cleaning unit is capable of cleaning the filter screen by one or more of the following methods: gas blowing, liquid flushing, and brush vibration.

[0012] Further, the cleaning unit comprises a nozzle arranged outside the air vent, the nozzle being arranged between the air vent and the filter screen through an air pipe, and a first electromagnetic valve being arranged on the air pipe to control the starting of the nozzle.

[0013] Further, the moving unit comprises a sliding rail arranged along the moving direction of the filter screen, the filter screen being controlled by a driving member and being slidingly connected to the sliding rail.

[0014] Further, the length of the filter screen is not less than twice the length of the air vent, and the filter screen comprises a first part and a second part along the moving direction of the filter screen, the second part being arranged outside the air vent when the first part is cleaned.

[0015] Further, a blocking part is arranged in the stroke of the filter screen to control the filter screen to stay at a target position.

[0016] Further, the central control unit adopts a DCS control system.

[0017] The utility model provides a filter screen self-cleaning system, including central control unit, air pressure monitoring unit, cleaning unit and moving unit, air pressure monitoring unit is used to receive the air pressure of filter screen both sides and passes to central control unit, and central control unit judges the cleaning time of filter screen according to the air pressure information detected, wherein the cleaning unit can automatically clean the surface of filter screen, and the moving unit can automatically control filter screen to move to the cleaning area.

[0018] The utility model also provides a paper machine's hot air system, including heat exchanger, the wet end circulation pipeline and dry end circulation pipeline connected between heat exchanger and the dry material, the new air inlet of heat exchanger is provided with above-mentioned filter screen self-cleaning system.

[0019] Further, the dry end circulation pipeline is provided with a dry end air bellow, and the wet end circulation pipeline is provided with a wet end air bellow, the dry end air bellow and the wet end air bellow are used for receiving the moisture of the dry material, and the moisture inlet of the dry end air bellow and the wet end air bellow is provided with the filter screen self-cleaning system.

[0020] This invention also provides a hot air system for a paper machine. The filter self-cleaning system not only has a heat exchange inlet to filter dust carried by the fresh air, but can also be installed at corresponding positions in the dry and wet end circulation pipes to filter the dried, wet air. The hot air system including the aforementioned filter self-cleaning system can automatically complete the filtration process during airflow circulation, offering advantages such as high automation and excellent cleaning effect. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a filter self-cleaning system according to this utility model;

[0022] Figure 2 This is a schematic diagram of the nozzles arranged on the trachea in Example 1;

[0023] Figure 3 This is a side view of the filter screen sliding connection frame;

[0024] Figure 4 This is a schematic diagram of the hot air system of a paper machine according to the present invention.

[0025] Reference numerals: 1. Filter self-cleaning system; 11. Vent; 12. Filter; 121. First part; 122. Second part; 13. Air pressure monitoring unit; 131. Pressure sensor; 14. Cleaning unit; 141. Nozzle; 142. Air pipe; 143. First solenoid valve; 15. Moving unit; 151. Slide rail; 152. Frame; 153. Cylinder; 154. Second solenoid valve; 155. Limiting part; 16. Central control unit.

[0026] 2. Heat exchanger; 3. Object to be dried; 4. Dry end circulation pipeline; 41. Dry end air box; 42. Dry end fan; 43. Dry end air inlet section; 44. Dry end air outlet section; 5. Wet end circulation pipeline; 51. Wet end air box; 52. Wet end fan; 53. Wet end air inlet section; 54. Wet end air outlet section; 6. First pipeline; 7. Second pipeline; 8. Third pipeline. Detailed Implementation

[0027] Example 1: As Figures 1 to 3 The illustrated self-cleaning filter system 1 includes a filter 12 disposed at the equipment vent 11, with the filter 12 having an air inlet side and an air outlet side on its two sides. In this embodiment, the equipment is a heat exchanger 2 in a paper machine hot air system. Fresh air enters the heat exchanger 2 from the air inlet side, and after heating, it dries components such as the drying cylinder and protective cover. The fresh air may contain dust or fine particles, which can accumulate on the filter 12, affecting its ventilation capacity. Therefore, the filter 12 needs to be cleaned regularly.

[0028] The filter screen self-cleaning system 1 comprises a wind pressure monitoring unit 13, a cleaning unit 14, a moving unit 15 and a central control unit 16. The wind pressure monitoring unit 13 is used for monitoring the wind pressure on the air inlet side and the air outlet side, judging the accumulation state of dust on the filter screen 12 according to the pressure difference between the air inlet side and the air outlet side, and controlling the cleaning time. The cleaning unit 14 is used for cleaning the surface of the filter screen 12. The moving unit 15 controls the filter screen 12 to move to the cleaning area, avoids the obstruction of the ventilation opening 11 during the cleaning process, ensures the overall cleaning process, and prevents the dust from falling into the heat exchanger 2. The wind pressure monitoring unit 13, the cleaning unit 14 and the moving unit 15 are connected to the central control unit 16. The cleaning unit 14 and the moving unit 15 comprise executable elements, which can control the cleaning unit 14 and the moving unit 15 to start according to the pressure information fed back by the wind pressure monitoring unit 13.

[0029] Specifically, the wind pressure monitoring unit 13 comprises pressure sensors 131 arranged on the air inlet side and the air outlet side respectively. Each pressure sensor 131 can be matched with a pressure gauge to directly display the real-time wind pressure on both sides of the filter screen 12. The air inlet side pressure sensor 131 can monitor the initial pressure before the fresh air enters the filter screen 12, reflecting the wind power of the fresh air. The air outlet side pressure sensor 131 is used for monitoring the pressure after the fresh air enters the filter screen 12. The pressure difference p1 obtained by subtracting the air outlet side pressure from the air inlet side pressure can reflect the wind resistance of the filter screen 12, so as to judge the real-time blockage state of the filter screen 12.

[0030] Each pressure sensor 131 is connected to the central control unit 16, and the detected pressure information is fed back to the central control unit 16. The central control unit 16 calculates the detection pressure difference p1 in real time. The central control unit 16 is pre-set with a pressure difference information p2. The preset pressure difference p2 is set according to the actual working condition requirement. The detection pressure difference p1 is compared with the preset pressure difference p2. If p2≤p1, it indicates that the wind resistance of the filter screen 12 is large, and the fresh air cannot be stably supplied to the heat exchanger 2. At this time, the cleaning unit 14 and the moving unit 15 are controlled to start, and the filter screen 12 is cleaned.

[0031] In this embodiment, the cleaning unit 14 is mainly a blowing module, which includes a plurality of nozzles 141 located between the air vent 11 and the filter screen 12. The plurality of nozzles 141 are connected to the left and right sides of the air vent 11 through two air tubes 142, i.e., the cleaning area of the filter screen 12 is located on both sides of the air vent 11. Each air tube 142 is connected to a high-pressure gas source, and a first electromagnetic valve 143 is arranged on the air tube 142. The first electromagnetic valve 143 is connected to the central control unit 16 and controls the airflow to be sprayed from the nozzles 141 according to the instruction of the central control unit 16 to clean the dust on the filter screen 12. It should be noted that the position of the air tube 142 is not limited to the left and right sides of the air vent 11, and the position of each nozzle 141 can be adjusted according to the actual cleaning requirements. As shown in FIG. 2, each nozzle 141 is arranged along the extension direction of the air tube 142, and the distance between the nozzle 141 and the filter screen 12 is set according to the size of the gas source pressure to achieve sufficient cleaning. The distance between adjacent nozzles 141 is set according to the spraying range of the nozzle 141, and the overlapping cleaning area of the two nozzles 141 on the filter screen 12 is preferably not less than half of the cleaning area of a single nozzle 141, so that each part of the filter screen 12 can be fully cleaned, and the generation of a cleaning dead angle is avoided. Figure 2

[0032] In addition, the cleaning unit 14 can be replaced with other dust removal modes, which only need to include a cleaning element for cleaning the surface of the filter screen 12, and the cleaning element can be started according to the instruction of the central control unit 16. For example, a plurality of electric brushes are arranged to vibrate and remove dust from the surface of the filter screen 12; or a water pipe connected to a water source is arranged to flush the surface of the filter screen 12 with water flow or medicament; and other common vibration and flushing dust removal modes.

[0033] The moving unit 15 includes two sliding rails 151 arranged in the moving direction of the filter screen 12, corresponding to the arrangement direction of the nozzles 141. The sliding rails 151 extend in the horizontal direction, and the filter screen 12 is slidingly connected in the sliding rails 151. The cleaning areas of the two groups of nozzles 141 cover the filter screen 12 in the height direction, and in the process of moving the filter screen 12 along the sliding rails 151, the airflow sprayed from the nozzles 141 passes through the mesh holes of the filter screen 12 to dynamically clean the entire area of the filter screen 12. Further, the moving unit 15 includes a frame 152 connected to the outer side of the air vent 11. The frame 152 has a U-shaped cross section, the filter screen 12 is accommodated in the inner side of the frame 152, and the two horizontal edges of the frame 152 are in sliding contact with the two long edges of the filter screen 12, respectively, so as to limit the relative position of the filter screen 12 and the filter screen 12.

[0034] ​In the embodiment, the length of the filter screen 12 is set to be not less than twice the length of the air vent 11, and includes a first part 121 and a second part 122 along the moving direction of the filter screen 12. In normal state, the first part 121 is opposite to the outer side of the air vent 11, and during cleaning, the first part 121 is moved to a cleaning position along the slide rail 151, and the second part 122 is opposite to the outer side of the air vent 11; after the first part 121 is cleaned, it is returned to the air vent 11. During the cleaning process of the filter screen 12, the outer side of the air vent 11 is always covered by the filter screen 12, so that dust carried by fresh air is prevented from entering the air vent 11 when the filter screen 12 is cleaned; similarly, the first part 121 and the second part 122 can also be arranged in a structure for mutual backup, and after the first part 121 is cleaned, it is not immediately returned to work, and when the second part 122 has excessive dust, the filter screen 12 is controlled to move, and the second part 122 is cleaned, so that the cleaning of the filter area is rotated.

[0035] As shown in Figure 3 , the driving member of the filter screen 12 is a cylinder 153 arranged at the bottom of the filter screen 12, the output end of the cylinder 153 is connected to one side of the width of the filter screen 12, and a second electromagnetic valve 154 is arranged on the pipeline connected with the air source of the cylinder 153, the second electromagnetic valve 154 is opened according to the information of the central control unit 16, and the stroke of the cylinder 153 is controlled.

[0036] Further, a limiting part 155 is arranged in the stroke of the filter screen 12, and the filter screen 12 is blocked by the limiting part 155 when it moves to the target stroke position, so that the filter screen 12 is prevented from continuing to move. The limiting part 155 can be arranged on the external pipeline, and a corresponding pin or stopper is arranged on the edge of the filter screen 12.

[0037] Further, the driving member of the filter screen 12 is not limited to the direct driving element such as the cylinder 153, but can also be a lead screw structure driven to rotate by a motor, the lead screw and the motor are fixedly connected to the frame 152, and the filter screen 12 is drivingly connected to the lead screw.

[0038] In the embodiment, the central control unit 16 adopts a DCS control system, global management is realized by a central control room, and the air pressure monitoring unit 13, the cleaning unit 14 and the moving unit 15 are regulated and controlled by multiple decentralized units. The central control unit 16 also includes an operation interface to display the differential pressure information of the air pressure monitoring unit 13, the state information of the cleaning unit 14 and the moving unit 15, and can remotely adjust the valve opening degree, start and stop the equipment, etc.

[0039] Embodiment 2: as Figure 4The hot air system of a paper machine shown in the embodiment comprises a heat exchanger 2, a dried object 3, a wet end circulation pipeline 5 and a dry end circulation pipeline 4 connected between the heat exchanger 2 and the dried object 3, the fresh air inlet of the heat exchanger 2 is provided with the filter screen self-cleaning system 1, the fresh air entering the heat exchanger 2 is filtered, and the heat exchanger 2 heats the filtered fresh air.

[0040] The dry end circulation pipeline 4 is the region where the hot air blows to the dried object, the dry end circulation pipeline 4 is provided with a dry end air bellow 41, which is connected to the hot gas outlet of the heat exchanger 2 through a first pipeline 6 to receive the hot gas flow after heat exchange. The humidity of the gas in the dry end circulation pipeline 4 is low, the dry end circulation pipeline 4 has a dry end air inlet section 43 and a dry end air outlet section 44 connected to the dried object 3, and the hot gas flow is circulated in the dry end circulation pipeline 4 by the dry end air blower 42. The dry end air outlet section 44 is connected to the wet end air bellow 51 of the wet end circulation pipeline 5 through a second pipeline 7, and the moisture of the dried gas enters the wet end circulation pipeline 5.

[0041] Compared with the dry end circulation pipeline 4, the humidity of the gas in the wet end circulation pipeline 5 is higher, the wet end circulation pipeline 5 is internally provided with a wet end air blower 52, including a wet end air inlet section 53 and a wet end air outlet section 54, for circulating the gas flow and maintaining the air pressure balance in the pipeline. The wet end circulation pipeline 5 is connected to the heat exchanger 2 through a third pipeline 8, part of the moisture is discharged to the outside through a fourth pipeline of the heat exchanger 2, part of the moisture is dried by heat exchange in the heat exchanger 2, and then is transmitted to the dry end circulation pipeline 4 through the first pipeline 6, and dries the dried object 3 together with the fresh air, which plays a role of balancing the air pressure and recycling the energy.

[0042] It should be noted that the filter screen self-cleaning system 1 provided in the embodiment 1 is not limited to the fresh air inlet of the heat exchanger 2, and can also be arranged at the air inlets of the dry end air bellow 41 and the wet end air bellow 51 to filter the dried moisture. Figure 4 As can be seen, the filter screen self-cleaning system 1 can also be arranged at the air inlets of the dry end air bellow 41 and the wet end air bellow 51 to filter the dried moisture, which can effectively prevent the hot gas flow from carrying too much dust in the drying process and bringing it into the circulation drying system again to pollute the dried object 3.

[0043] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and cannot be understood as limiting the present application, and those skilled in the art can make changes, modifications, replacements and modifications to the above embodiments within the scope of the present application.

Claims

1. A filter screen self-cleaning system characterized by: The utility model relates to a filter screen self-cleaning system for heat exchanger, comprising, a filter screen (12) movably arranged outside the air vent (11); a wind pressure monitoring unit (13) for monitoring the pressure difference information between the air inlet side and the air outlet side of the filter screen (12); a cleaning unit (14) arranged outside the air vent (11) for cleaning the surface of the filter screen (12) when the filter screen (12) moves; a moving unit (15) arranged outside the air vent (11) for controlling the filter screen (12) to move to a cleaning area; a central control unit (16) for receiving the pressure difference information fed back by the wind pressure monitoring unit (13) and issuing a work instruction according to the pressure difference information; the cleaning unit (14) and the moving unit (15) are respectively provided with executable elements capable of controlling the cleaning unit (14) and the moving unit (15) to work according to the instruction issued by the central control unit (16).

2. A filter screen self-cleaning system as claimed in claim 1, characterized in that: The central control unit (16) is pre-set with pressure difference information, and when the detected pressure difference is not less than the pre-set pressure difference, a work instruction is issued.

3. A filter screen self-cleaning system as claimed in claim 1, wherein: The cleaning unit (14) can clean the filter screen in one or more of the following ways: gas blowing, liquid flushing, and brush vibration dust removal.

4. The filter screen self-cleaning system of claim 1, wherein: The cleaning unit (14) comprises a nozzle (141) arranged outside the air vent (11), the nozzle (141) is arranged between the air vent (11) and the filter screen (12) through an air pipe (142), and a first electromagnetic valve (143) for controlling the start of the nozzle (141) is arranged on the air pipe (142).

5. The filter screen self-cleaning system of claim 1, wherein: The moving unit (15) comprises a slide rail (151) arranged in the moving direction of the filter screen (12), and the filter screen (12) is controlled by a driving member and is slidably connected in the slide rail (151).

6. A filter screen self-cleaning system as claimed in claim 1, wherein: The length of the filter screen (12) is not less than twice the length of the air vent (11), and the filter screen (12) comprises a first part (121) and a second part (122) in the moving direction of the filter screen (12), and when the first part (121) is cleaned, the second part (122) is shielded outside the air vent (11).

7. A filter screen self-cleaning system as claimed in claim 5, wherein: A blocking part (155) is arranged in the stroke of the filter screen (12) for controlling the filter screen (12) to stay at a target position.

8. A filter screen self-cleaning system as claimed in claim 1, wherein: The central control unit (16) adopts a DCS control system.

9. A hot air system of a paper machine, comprising a heat exchanger (2), a wet end circulation line (5) and a dry end circulation line (4) connected between the heat exchanger (2) and a material to be dried (3), characterized in that: The fresh air inlet of the heat exchanger (2) is provided with the filter screen self-cleaning system according to any one of claims 1-8.

10. The paper machine's hot air system as claimed in claim 9, characterized in that A dry end air bellow (41) is arranged on the dry end circulation pipeline (4), and a wet end air bellow (51) is arranged on the wet end circulation pipeline (5), the dry end air bellow (41) and the wet end air bellow (51) are used for receiving the moisture of the dried material (3), and the moisture inlets of the dry end air bellow (41) and the wet end air bellow (51) are provided with the filter screen self-cleaning system according to any one of claims 1-8.

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