Paving method for water-containing materials

Abstract

A method for spreading water-containing materials, comprising: in the process of spreading cloth by a spreading device, in a unit time, in the direction of movement of the filter cloth, the length of the filter cloth released from the cloth roll is greater than the length of the filter cloth laid on the bottom plate of the filter cylinder. On the one hand, the spreading of the filter cloth is carried out synchronously with the spraying of sludge, and on the other hand, the filter cloth is pushed with little obstruction, thereby increasing the spreading speed of the filter cloth. Thus, the efficiency of the entire sludge dehydration is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of sludge treatment, and in particular relates to a method for spreading water-containing materials in a dehydration device, and more particularly to a method for spreading water-containing materials in a process of pushing a filter cloth. Background Art

[0002] In industry and daily life, a large amount of sludge is generated. Proper treatment and disposal of this growing amount of sludge has become an urgent problem to be solved in environmental protection. Sludge generally refers to a thick substance between liquid and solid. It can be transported by pumps, but it is difficult to separate solids and liquids through sedimentation. The concentration of suspended matter is generally 1% to 10%, and below this concentration is often called mud. Due to different sources of sludge and water treatment methods, the properties of the sludge produced are different. There are many types of sludge, and the classification is relatively complicated. Correspondingly, there are also many treatment methods.

[0003] Sludge dewatering is an important part of the whole sludge treatment process. Its purpose is to enrich the solids, reduce the sludge volume, and create conditions for the final disposal of the sludge. In order to separate the liquid phase and the solid phase of the sludge, the binding force between them must be overcome, so the main problem encountered in sludge dewatering is the energy problem. According to the different forms of binding force, different external measures can be used to achieve different dewatering effects, such as natural dehydration or mechanical dehydration.

[0004] Mechanical dehydration is a commonly used dehydration method. Multiple layers of sludge are wrapped with filter cloth and stacked vertically in the filter cylinder. The sludge is squeezed by the squeezing unit to separate the solid and liquid of the sludge. The general operation process includes: firstly laying the filter cloth flat, and then laying the sludge on the filter cloth. After the multiple layers of sludge are laid, the squeezing unit squeezes them. For example, the patent application No. CN114919221A submitted by the applicant discloses a multi-layer stacking solid-liquid separation method. In this method, after the filter cloth is laid, the sludge is sprayed onto the filter cloth above the laid filter cloth.

[0005] Chinese patent application number CN202023099235.0 discloses a fixing device for laying laminated filter cloth, which lays sludge on the filter cloth while laying the filter cloth. Specifically, the proximal end of the filter cloth is first pressed tightly, and the filter cloth is fed forward by the discharge port of the sludge spreading mechanism. During the feeding process of the sludge spreading mechanism, the discharge port of the sludge spreading mechanism spreads the sludge evenly on the filter cloth. In the process of spreading the sludge, the sludge spreading mechanism actually uses the sludge to press the filter cloth tightly, so that the filter cloth is unwound from the cloth roll.

[0006] In the process of mechanical dehydration of sludge, the laying effect and efficiency of sludge is a very important link in sludge treatment and is a technical point of concern to technicians in this field. Summary of the invention

[0007] One purpose of the present invention is to improve the efficiency of laying sludge on the filter cloth, on the one hand, the pushing and laying of the filter cloth is carried out simultaneously with the sludge spraying, and on the other hand, the filter cloth is pushed with less obstruction, thereby increasing the laying speed of the filter cloth. In turn, the efficiency of the entire sludge dewatering is improved.

[0008] Another object of the present invention is that sludge will not adhere to the cloth pushing and spreading device during the process of pushing the cloth, spraying the sludge, and retreating.

[0009] A method for laying sludge on sludge dewatering equipment comprises: in the process of pushing cloth by a cloth pushing and spreading device, in a unit time, in the direction of movement of the filter cloth, the length of the filter cloth released from the cloth winding roller is greater than the length of the filter cloth laid on the bottom plate of the filter cylinder.

[0010] That is, when the cloth-pushing and spreading device is pushing the cloth, there is excess filter cloth unrolled from the cloth-winding roller, and the cloth-pushing and spreading device is almost not subject to the resistance of the filter cloth to the cloth-pushing and spreading device, so the cloth-pushing and spreading can be pushed and spread quickly, thereby improving the spreading efficiency. For example, a section of filter cloth can be unrolled from the cloth-winding roller in advance before the cloth-pushing and spreading device pushes the cloth.

[0011] A sludge dewatering device is used to implement the above-mentioned method of laying sludge. The device includes a cloth pushing and spreading device and a filter cloth winding and unwinding device; the filter cloth winding and unwinding device is arranged on one side of the filter cylinder, and the cloth pushing and spreading device is arranged above the filter cylinder and moves back and forth in the horizontal direction of the side where the filter cloth winding and unwinding device is arranged; the filter cloth winding and unwinding device includes a cloth winding roller and a plurality of cloth guide rollers, the filter cloth is wound on the cloth winding roller, and the first end of the filter cloth is located in the filter cloth roll; in the working state, the second end of the filter cloth is arranged and fixed on the filter cylinder, and the length of the filter cloth between the cloth winding roller and the first cloth guide roller in the direction of movement of the filter cloth is greater than the straight-line distance between the cloth winding roller and the first guide roller; the filter cloth winding and unwinding device is provided with a first position sensor for sensing whether the lowest part of the filter cloth released between the cloth winding roller and the first cloth guide roller is in the first position.

[0012] During the operation of the sludge dewatering equipment of the present application, in the working state, for example, during the cloth spreading process, the length of the filter cloth between the cloth winding roller and the first cloth guide roller in the direction of movement of the filter cloth is greater than the straight-line distance between the cloth winding roller and the first guide roller, and the resistance of the filter cloth to the cloth pushing and spreading device is minimal, so the cloth can be pushed and spread quickly, thereby improving the efficiency of cloth spreading and spreading. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of an implementation method of the sludge dewatering equipment of the present application;

[0014] Figure 2 This application Figure 1 A partial enlarged view of the sludge dewatering equipment;

[0015] Figure 3 It is a structural schematic diagram of the mud paving assembly of the present application;

[0016] Figure 4 It is a structural schematic diagram of an implementation mode of the cloth pushing and spreading device of the present application;

[0017] Figure 5 yes Figure 4 A schematic cross-sectional view of a cloth-pushing and spreading device;

[0018] Figure 6 yes Figure 5 A partial enlarged view of the cloth-pushing and spreading device;

[0019] Figure 7 It is a schematic diagram of a working state of a cloth-pushing and spreading device;

[0020] Figure 8 It is a schematic diagram of the second working state of the cloth-pushing and spreading device;

[0021] Fig. 9 It is a structural schematic diagram of another embodiment of the sludge dewatering equipment of the present application;

[0022] Fig.10 It is a schematic diagram of a prior art mud paving assembly. DETAILED DESCRIPTION

[0023] The following is a further detailed description of the method for laying sludge on the sludge dewatering device of the present invention, which does not limit the scope of protection of the present application, and its scope of protection is defined by the claims. Certain disclosed specific details provide a comprehensive understanding of each disclosed embodiment. However, those skilled in the relevant art know that the embodiment can be implemented without using one or more of these specific details and using other materials, etc.

[0024] Unless the context requires otherwise, in the specification and claims, the terms "include" and "comprising" should be construed as having an open-ended, inclusive meaning, that is, "including, but not limited to".

[0025] The "embodiment", "one embodiment", "another embodiment" or "certain embodiments" mentioned in the specification means that the specific features, structures or characteristics described in connection with the embodiment are included in at least one embodiment. Therefore, "embodiment", "one embodiment", "another embodiment" or "certain embodiments" do not necessarily all refer to the same embodiment. And the specific features, structures or characteristics can be combined in any way in one or more embodiments. Each feature disclosed in the specification can be replaced by any alternative feature that can provide the same, equal or similar purpose. Therefore, unless otherwise specified, the disclosed features are only general examples of equal or similar features.

[0026] In order to reduce the time taken by the sludge dewatering equipment to lay multiple layers of sludge, the cloth-pushing and spreading device sprays sludge while laying the filter cloth, and the retreat rate of the cloth-pushing and spreading device can be accelerated, thereby improving the efficiency of the overall sludge dewatering process.

[0027] A method for laying sludge on a sludge dewatering device comprises: before a cloth pushing and spreading device pushes the cloth, releasing a section of the filter cloth from a cloth rolling roller; in the moving direction of the filter cloth, the length of the released filter cloth is greater than or equal to the length of the filter cloth laid on the bottom plate of a filter cylinder; wherein the filter cloth is wound on the cloth rolling roller, the first end of the filter cloth is located in the filter cloth roll, the cloth rolling roller and the cloth pushing and spreading device are located on the same side of the filter cylinder, and the cloth pushing and spreading device is located above the filter cylinder; in a working state, the second end of the filter cloth is configured and fixed on the filter cylinder.

[0028] In an optional solution, the length of the released filter cloth in the moving direction of the filter cloth is greater than or equal to the length of the filter cloth laid on the filter cylinder bottom plate. It can also be understood that the length of the released filter cloth is greater than or equal to twice the length of the filter cylinder bottom plate in the moving direction of the filter cloth.

[0029] During each material spreading process, the cloth pushing and spreading device pushes the filter cloth between the filter cylinder and the cloth rolling roller from the first side wall of the filter cylinder to the opposite second side wall, and the cloth pushing and spreading device sprays sludge onto the filter cloth on the lower layer during the movement, wherein the first side wall of the filter cylinder is closer to the cloth rolling roller than the second side wall; the cloth pushing and spreading device does not spray sludge during the movement from the second side wall of the filter cylinder to the first side wall.

[0030] In some embodiments, the first speed of the cloth spreading device moving from the first side wall to the second side wall of the filter cylinder is less than the second speed of the cloth spreading device moving from the second side wall to the first side wall of the filter cylinder, wherein the filter cloth is spread and the sludge is sprayed during the movement from the first side wall to the second side wall.

[0031] In the existing sludge laying method, the cloth spreading device uses the force of the cloth pushing to release the filter cloth from the cloth rolling roller and lay it on the filter cylinder. During the cloth pushing process, the filter cloth is in a tensioned state, and the cloth pushing and spreading device is subjected to the resistance of the filter cloth when pushing the cloth. The cloth pushing speed is relatively low, so it takes a long time to lay each layer of sludge. Alternatively, when moving from the first side wall to the second side wall of the filter cylinder, the sludge is not sprayed, and the filter cloth is only spread on the bottom plate of the filter cylinder; when retreating from the second side wall to the first side wall, the sludge is sprayed to the lower filter cloth. When retreating, due to the spraying of sludge, the second speed cannot be too fast, so the first speed and the second speed are relatively low.

[0032] In the method for laying sludge of the present application, during the process of pushing the cloth and laying the material, the resistance of the filter cloth is small, the first speed of the cloth pushing and laying device can be increased, and the second speed of retreat is faster, so the time for laying each layer of sludge can be greatly shortened.

[0033] In some embodiments, during the time that the cloth pushing and spreading device moves from the second side wall of the filter cylinder to the first side wall, the length of the filter cloth released from the cloth rolling roller is greater than or equal to the length of the filter cloth laid on the bottom plate of the filter cylinder. That is, the length of the released filter cloth is greater than or equal to twice the length of the bottom plate of the filter cylinder in the direction of movement of the filter cloth.

[0034] In some embodiments, the filter cloth released from the cloth winding roller is V-shaped, and in the cloth pushing working state, the lowest part of the V-shape moves between a first position and a third position below the cloth winding roller and the first cloth guide roller, wherein in the vertical direction, the first position is lower than the third position.

[0035] The filter cloth itself has a certain weight, and the filter cloth released in advance from the cloth winding roller is supported between the cloth winding roller and the first cloth guide roller, and presents a V shape. The lowest part of the above-mentioned V shape is not limited to the position of the lowest point of the V shape, and can be a position near the lowest point of the V shape.

[0036] Each layer of paving process in the present application may include a cloth pushing process of the cloth pushing paving device and a retreat process of the cloth pushing paving device. The cloth pushing process is a process in which the cloth pushing paving device moves from the first side wall to the second side wall of the filter cylinder; the retreat process is a process in which the cloth pushing paving device moves from the second side wall to the first side wall of the filter cylinder.

[0037] When the lowest part of the filter cloth released from the cloth winding roller is at the first position, L1-L2≥2L, wherein L1 is the total length of the filter cloth released from the cloth winding roller, L2 is the straight-line distance between the cloth winding roller and the first cloth guide roller, and L is the length of the bottom plate in the moving direction of the filter cloth.

[0038] When the lowest part of the filter cloth released from the cloth roller is at the third position, the length of the filter cloth will be equal to the straight-line distance between the cloth roller and the first cloth guide roller, that is, the filter cloth will be in a taut state. At this time, the cloth release speed of the cloth roller can be increased, or the cloth spreading can be stopped to check whether each component can work normally.

[0039] An optional solution is to adjust the rotation speed of the cloth winding roller during the entire material laying process so that the lowest point of the filter cloth released from the cloth winding roller is between the first position and the second position; in the vertical direction, the second position is between the first position and the third position.

[0040] In this solution, during the cloth pushing process and the backward process of the cloth pushing and spreading device, the lowest part of the filter cloth released from the cloth rolling roller is always located between the first position and the second position, and the filter cloth is in a relaxed state between these two positions. When the lowest part of the filter cloth released from the cloth rolling roller reaches the third position, the filter cloth is about to be in a tightened state.

[0041] In practical applications, the movement trajectory of the filter cloth is determined based on factors such as the processing scale of the equipment and the material laying requirements, and then the above-mentioned sensing positions, namely the first position, the second position and the third position, can be determined.

[0042] An optional solution, the mud spreading component of the cloth pushing and spreading device of the present application includes: a first component and a second component respectively having a channel, the second end of the second component is provided with a discharge port, the second end of the first component is connected to the first end of the second component, so that the first component channel is connected to the second component channel; the cross-section of the channel of the second component is the same in a direction perpendicular to the forward direction of the sludge, and the bottom surface of the second component supporting the sludge is a plane; the cross-sectional area of ​​the first component channel at the second end is smaller than the cross-sectional area at the first end, and the cross-sectional area of ​​the second component channel is the same as the cross-sectional area of ​​the first component channel at the second end.

[0043] The first end of the first component is connected to the channel of the third component for conveying sludge. The sludge from the third component enters the second component from the end with a larger cross-sectional area of ​​the first component, and through the change in the cross-sectional area of ​​the second component channel, it acts as a pressurizer in the second component channel, and the sludge is distributed wider in the horizontal direction perpendicular to the flow of sludge in the second component (i.e., the width of the channel). After flowing into the second component from the end with a smaller cross-sectional area of ​​the first component, the sludge is further distributed horizontally wider in the channel of the second component, and can occupy the entire second component channel, and evenly flows out at the discharge port of the second component and is laid on the filter cloth.

[0044] In certain embodiments, in a horizontal direction perpendicular to the sludge flow direction, the width of the second end of the first component channel is greater than the width of the first end.

[0045] In the vertical direction perpendicular to the sludge flow direction, the height of the second end of the first component channel is smaller than the height of the first end.

[0046] Optionally, the width of the channel of the first component gradually increases from the first end to the second end.

[0047] The height of the channel of the first component gradually decreases from the first end to the second end.

[0048] Through the setting of the first component channel structure, the sludge enters the channel through the first section of the first component. During the forward process, the pressure gradually increases, and the sludge occupies the first component and gradually disperses continuously from the center to both sides. The bottom of the first component channel moves from the center to both sides in the width direction.

[0049] In certain embodiments, the cross-sectional area of ​​the first component channel at the second end is 0.7-1.0 times the cross-sectional area of ​​the first end.

[0050] In certain embodiments, the ratio of the length of the first component in the sludge flow direction to the width of the first component channel at the second end is 1:0.6 to 1:3.

[0051] The width of the second end of the first component refers to the length of the second component channel in the horizontal direction perpendicular to the sludge flow direction.

[0052] The length of the first component refers to the length between the first end and the second end.

[0053] In certain embodiments, in the sludge flow direction, the ratio of the length L1 of the first component to the length L2 of the second component is 1:0.5-1:8.

[0054] The cloth-pushing and spreading device with the above-mentioned mud-spreading assembly of the present application pushes the cloth relatively quickly, and correspondingly, the mud also flows out from the spreading port quickly and evenly, and the mud is spread on the filter cloth more evenly.

[0055] on the other hand There are many kinds of dewatering equipment to implement the above-mentioned method of laying sludge, and the following equipment is preferred.

[0056] A sludge dewatering device comprises: a cloth pushing and spreading device and a filter cloth winding and unwinding device; the filter cloth winding and unwinding device is arranged on one side of a filter cylinder, the cloth pushing and spreading device is arranged above the filter cylinder, and moves back and forth in a horizontal direction on the side where the filter cloth winding and unwinding device is arranged; the filter cloth winding and unwinding device comprises a cloth winding roller and a plurality of cloth guide rollers, the filter cloth is wound on the cloth winding roller, and the first end of the filter cloth is located in the filter cloth roll; in a working state, the second end of the filter cloth is arranged and fixed on the filter cylinder, and the length of the filter cloth between the cloth winding roller and the first cloth guide roller in the filter cloth movement direction is greater than the straight-line distance between the cloth winding roller and the first guide roller; a first position sensor is arranged on the filter cloth winding and unwinding device, for sensing whether the lowest part of the filter cloth unrolled from the cloth winding roller is in the first position.

[0057] A second position sensor is arranged on the filter cloth winding device for sensing whether the lowest part of the filter cloth unwinding from the cloth winding roller is at the second position.

[0058] A third position sensor is arranged on the filter cloth winding device for sensing whether the lowest part of the filter cloth unwinding from the cloth winding roller is at the third position.

[0059] The first, second and third position sensors may be contact position sensors; or proximity sensors, such as electromagnetic, photoelectric, differential edge pressure, eddy current, capacitance, reed switch, Hall, or ultrasonic sensors.

[0060] In some embodiments, the first position sensor may be a contact position sensor, and the first position sensor is located below the cloth winding roller and the first cloth guiding roller and between their horizontal projections, so that the first position sensor can contact the filter cloth.

[0061] In some other embodiments, the first position sensor may be a proximity position sensor, and the first position sensor may sense the lowest position of the released filter cloth. For example, the first position sensor is located below the cloth winding roller and the first cloth guide roller, and does not need to contact the filter cloth, and may sense the filter cloth by other means such as infrared or laser.

[0062] The filter cloth has a certain weight. The filter cloth released from the cloth winding roller moves downward between the cloth winding roller and the first guide roller under the action of gravity. The position sensor can sense the position of the filter cloth moving downward, and then according to the position relationship between the cloth winding roller and the first guide roller (such as the height of the two, the straight-line distance between the two) and the setting position of the position sensor, the length of the released filter cloth can be obtained.

[0063] For example: in the vertical direction, the cloth winding roller is higher than the first cloth guide roller, and the third position sensor is arranged between the first cloth guide roller and the first position sensor; or, in the vertical direction, the cloth winding roller is lower than the first cloth guide roller, and the third position sensor is arranged between the cloth winding roller and the first position sensor.

[0064] In some embodiments, the third position sensor is a contact position sensor. In the vertical direction, the third position sensor is about 10-30 cm lower than the height of the first cloth guide roller or the cloth winding roller.

[0065] When the third position sensor senses the filter cloth, it indicates that the filter cloth released from the cloth roller is about to be in a tensioned state. At this time, the cloth roller can be driven to release the cloth or the cloth release speed of the cloth roller can be increased to ensure that the filter cloth is in a relaxed state during the spreading process of the dehydration equipment.

[0066] In certain embodiments, the cloth pushing and spreading device pushes the filter cloth forward, and during the movement from the first side wall of the filter cylinder to the opposite second side wall, the cloth rolling roller is in a non-working state; during the movement of the cloth pushing and spreading device from the second side wall to the first side wall of the filter cylinder, the cloth rolling roller is driven to rotate to release a section of filter cloth; when the front end of the cloth pushing and spreading device in the forward direction is at the first side wall of the filter cylinder, the length of the filter cloth released by the cloth rolling roller is greater than the length of the filter cloth laid on the bottom plate of the filter cylinder.

[0067] During the spreading process, when the cloth pushing and spreading device moves from the second side wall of the filter cylinder to the first side wall, the cloth rolling roller rotates at a constant speed to unwind a certain length of filter cloth from the cloth rolling roller. When the cloth pushing and spreading device pushes the cloth, the cloth rolling roller stops working.

[0068] Alternatively, during the spreading process, the cloth rolling roller works alternately at two speeds. When the cloth pushing and spreading device moves from the second side wall of the filter cylinder to the first side wall, the cloth rolling roller rotates at the first speed to unwind a certain length of filter cloth from the cloth rolling roller; when the cloth pushing and spreading device pushes the cloth, the cloth rolling roller rotates at the second speed, and the first speed is greater than the second speed.

[0069] The total length of the filter cloth released by the cloth rolling roller at the first speed and the filter cloth released by the cloth rolling roller at the second speed is greater than twice the length of the filter cloth laid on the bottom plate of the filter cylinder; preferably, the filter cloth released by the cloth rolling roller at the first speed accounts for more than 2 / 3 of the total length of the released filter cloth. This ensures that the filter cloth is always relaxed when the cloth pushing and spreading device is pushing the cloth.

[0070] A method for controlling the above-mentioned sludge dewatering equipment comprises: 1) the cloth rolling roller rotates to release a section of the filter cloth rolled on the cloth rolling roller; when the first position sensor senses the filter cloth, the cloth rolling roller stops releasing the cloth; 2) the cloth pushing and spreading device pushes the filter cloth from the first side wall of the filter cylinder to the second side wall, and during the cloth pushing process, sludge is sprayed onto the lower filter cloth to complete the laying of a layer of sludge; 3) during the process of the cloth pushing and spreading device moving from the second side wall of the filter cylinder to the first side wall, the cloth rolling roller rotates and repeats step 1) to release a section of the filter cloth from the cloth rolling roller; 4) in the horizontal direction, the cloth pushing and spreading device moves outside the filter cylinder, and the first cloth pressing assembly presses the filter cloth above the first side wall of the filter cylinder onto the side wall at the top of the filter cylinder; and steps 2) - 4) are repeated in sequence.

[0071] Generally, the filter cylinder is a prism structure with a rectangular or square cross section. The upper and lower ends of the filter cylinder are open. A bottom plate that can move up and down is arranged inside the filter cylinder. The filter cloth is laid on the bottom plate of the filter cylinder, and the sludge is sprayed on the filter cloth. After each layer of sludge is laid, the bottom plate moves downward so that the upper surface of the laid layer of sludge is basically on the same plane as the top of the filter cylinder, and then the next layer of sludge is laid.

[0072] In specific operation, a variety of methods can be used to determine whether the cloth-pushing and spreading device pushes the filter cloth from the first side wall of the filter cylinder to the second side wall. For example, by setting the time, the cloth-pushing and spreading device moves at a uniform speed. According to its forward speed and the distance from the first side wall to the second side wall of the filter cylinder, the running time t can be obtained. After time t, the cloth-pushing and spreading device retreats, and the cloth-rolling roller starts to rotate to release the cloth. The rotation time and speed of the cloth-rolling roller can also be determined according to the length of the released filter cloth, the cloth-pushing and spreading device from the second side wall to the initial position (i.e., the position where the cloth is started to be pushed), and the movement speed. In short, during the process of the cloth-pushing and spreading device pushing the cloth from the first side wall of the filter cylinder to the second side wall, the cloth-rolling roller remains inactive and the filter cloth is in a relaxing device; during the process of the cloth-pushing and spreading device pushing the cloth from the second side wall of the filter cylinder to the first side wall (the position where the cloth is started to be pushed), the cloth-rolling roller rotates, and the length of the released filter cloth meets the amount required for laying each layer of sludge, which is convenient for the next cloth-pushing and spreading.

[0073] The cloth rolling roller can also be controlled to rotate or not work by detecting the position of the cloth pushing and spreading device.

[0074] In some embodiments, during the entire spreading process, the rotation speed of the cloth rolling roller is adjusted so that the lowest part of the filter cloth released from the cloth rolling roller is located between the first position and the second position. This ensures that the filter cloth is in a relaxed state during the cloth pushing and spreading device, thereby reducing the resistance of the filter cloth to the cloth pushing and spreading device during the process.

[0075] In this solution, the working state of the cloth rolling roller has nothing to do with the moving position and moving speed of the cloth pushing and spreading device. It is only necessary to control the lowest part of the released filter cloth to be between the first position and the second position.

[0076] In some embodiments, among the plurality of cloth guide rollers, in the horizontal direction, the second cloth guide roller is closest to the filter cylinder and is located above the cloth pushing and spreading device. A first cloth pressing assembly is arranged near the first side wall of the filter cylinder to press the filter cloth above the first side wall of the filter cylinder onto the filter cylinder.

[0077] The cloth pushing and spreading device of the present application can be any device disclosed in the prior art to achieve this function.

[0078] Optionally, the cloth pushing and spreading device includes a shell and a mud spreading assembly disposed in the shell, a spreading opening is provided at the bottom of the shell, a cloth pushing head extending downwardly at an angle is provided at the front end of the shell, a first end of the cloth pushing head is connected to the shell, and a second end opposite to the first end is lower than the spreading opening at least when the cloth pushing head is in contact with the filter cloth.

[0079] Furthermore, at least when the cloth pushing head abuts against the filter cloth, the height difference between the second end of the cloth pushing head and the material laying opening is greater than the thickness of the material laid on the filter cloth;

[0080] Preferably, the material spreading opening is arranged close to the cloth pushing head.

[0081] In the cloth pushing process of the cloth pushing and spreading device of the present application, the cloth pushing head pushes the filter cloth, and uses the reaction force to flatten the filter cloth under the shell, and at the same time spreads the sludge on the filter cloth under the shell. The height difference between the second end of the cloth pushing head and the spreading opening can leave a space for the sludge to be spread between the filter cloth under the shell and the spreading opening, which can prevent the sludge from adhering to the shell and improve the spreading effect of the sludge.

[0082] Furthermore, the cloth pushing head is rotatably connected to the shell, and the cloth pushing head is configured with a first position for rotating upward to an upper limit, and a second position for rotating downward to a lower limit. When the cloth pushing head is in the first position and the second position, the height difference of the second end of the cloth pushing head is greater than the thickness of the material laid on the filter cloth.

[0083] Furthermore, when the cloth pushing head rotates to the first position, the height of the second end of the cloth pushing head is lower than the height of the rotation center of the cloth pushing head; an elastic member for driving the cloth pushing head to rotate to the first position is provided between the cloth pushing head and the shell.

[0084] Further, in a direction from the first end to the second end of the cloth pushing head, a thickness of the cloth pushing head in a direction perpendicular to the direction from the first end to the second end gradually decreases.

[0085] Furthermore, the cross-section of the second end of the cloth pushing head is configured to be an arc shape protruding in a direction away from the first end.

[0086] Preferably, in a direction perpendicular to the first end to the second end of the cloth pushing head, the maximum thickness of the arc shape of the second end of the cloth pushing head is smaller than the thickness of the first end of the cloth pushing head.

[0087] The above-mentioned cloth pushing head structure of the present application enables the cloth pushing head to support the filter cloth and feed it forward, and the filter cloth slides smoothly along the cloth pushing head, thereby reducing the resistance of the cloth pushing head to the filter cloth, improving the smoothness of the sliding of the filter cloth along the second end of the cloth pushing head, and avoiding the cloth pushing head from damaging the filter cloth during the cloth pushing process.

[0088] Furthermore, the second end of the cloth pushing head is a solid cylinder with a diameter smaller than the thickness of the front end of the shell. The solid cylinder is connected to the shell through a support plate extending downward from the front end of the shell. The end of the support plate away from the solid cylinder is the first end of the cloth pushing head.

[0089] Further, a support plate extends obliquely from the upper side of the solid column along the tangent direction of the solid body to the upper edge of the front end of the shell; or, two support plates extend obliquely from the upper and lower sides of the solid column along the tangent direction of the solid body to the upper and lower edges of the front end of the shell;

[0090] The end of the support plate is smoothly connected to the outer peripheral wall of the solid column.

[0091] Furthermore, a notch is provided in the middle of the second end of the cloth pushing head, which is adapted to the shape of the working end of the cloth pressing assembly arranged on the side of the filter cylinder away from the cloth pushing and spreading device, for the working end of the cloth pressing assembly to pass through and press the filter cloth covered on the second end of the cloth pushing head onto the filter cylinder.

[0092] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0093] Example 1

[0094] like Figure 1 , 2 As shown, a sludge dewatering device includes a cloth pushing and spreading device 1, a frame 4 and a filter cylinder 2. The frame 4 is located on one side of the first side wall of the filter cylinder 2. The cloth pushing and spreading device 1 is slidably arranged on the frame 4, and an extrusion device 8 is arranged directly above the filter cylinder.

[0095] A cloth winding roller 7 and a plurality of cloth guide rollers are arranged on the frame 4, and the filter cloth 71 is wound on the cloth winding roller 7, and the first end of the filter cloth 71 is located in the cloth roll of the cloth winding roller 7; during the spreading process, the other end of the filter cloth 71 is fixed on the filter cylinder; the filter cloth 71 released from the cloth winding roller 7 is laid on the bottom plate in the filter cylinder 2 through the guidance of a plurality of cloth guide rollers and the push of the cloth pushing and spreading device 1.

[0096] The cloth rolling roller 7 is located on the frame 4 farthest from the filter cylinder 2, the first cloth guide roller 72 among the plurality of cloth guide rollers is closest to the cloth rolling roller 7, and the second cloth guide roller 73 among the plurality of guide rollers is closest to the first side wall of the filter cylinder 2. Other cloth guide rollers are arranged between the first guide roller 72 and the second guide roller 73, and the filter cloth 71 is spread in a lateral direction perpendicular to the moving direction during operation, and each spreading of the cloth can at least cover the entire surface of the bottom plate inside the filter cylinder.

[0097] In the vertical direction, the first position sensor 74 and the third position sensor 75 are located below the cloth winding roller 7 and the first cloth guide roller 72, and the first position sensor 74 is located below the third sensor 75. The first and third position sensors can be contact sensors (travel switches, two-dimensional matrix type) and proximity sensors (such as electromagnetic, electro-optical, capacitive, reed switch, Hall type, etc.).

[0098] As attached Figure 1 As shown, the first and third position sensors are photoelectric sensors, and are located below the cloth winding roller 7 and the first cloth guide roller 72. When the first position sensor detects the filter cloth 7, the total length of the filter cloth released between the cloth winding roller 7 and the first cloth guide roller 72 is greater than twice the length of the bottom plate in the forward direction of the filter cloth.

[0099] In the vertical direction, the cloth rolling roller 7 and the first cloth guide roller 72 can be on the same plane, and the cloth rolling roller 7 can also be higher than the first cloth guide roller 72, or lower than the first cloth guide roller 72. In either case, the second position sensor 75 is slightly lower than the relatively lower component. In this arrangement, when the third position sensor 75 cannot detect the filter cloth 71, the filter cloth between the first cloth guide roller 72 and the cloth rolling roller 7 is about to be in a tensioned state, some components may fail, or the cloth releasing speed of the cloth rolling roller can be increased.

[0100] Generally, the filter cylinder 2 is a quadrangular prism structure with a rectangular cross section, and is open at the top and bottom. A bottom plate 21 is arranged in the filter cylinder 2. The cross section of the bottom plate 21 is substantially the same as the cross section of the cylinder body 2. The lengths of the sides of the bottom plate 21 are slightly smaller than the lengths of the corresponding cylinder bodies, so that the bottom plate 21 can move up and down in the filter cylinder 2. The bottom plate 21 is connected to a hydraulic rod 22, and the hydraulic rod 22 can drive the bottom plate to move up and down.

[0101] The first cloth pressing assembly 5 is respectively arranged at both ends of the first side wall of the filter cylinder 2, and the second cloth pressing assembly 6 is arranged on the second side wall opposite to the first side wall. In the process of the cloth pushing and spreading device 1 moving from the first side wall to the second side wall of the filter cylinder 2, the first cloth pressing assembly 5 presses the filter cloth 7 below the cloth spreading device 1 onto the side wall of the filter cylinder 2. During the movement, there are filter cloths 71 above and below the cloth pushing and spreading device 1, and the ejected sludge falls on the lower filter cloth. In the process of the cloth pushing and spreading device 1 moving from the second side wall to the first side wall of the filter cylinder 2, the second cloth pressing assembly 6 presses the filter cloth on the second side wall onto the filter cylinder 2. The cloth pushing and spreading device 1 withdraws from the outside of the filter cylinder 2, and the sludge on the bottom plate 21 is wrapped by the upper and lower layers of filter cloth.

[0102] Each component or part of the sludge dewatering equipment (such as a cloth rolling roller, a cloth pushing and spreading device, etc.) is electrically connected to the overall control module, and the operation or movement of each component is controlled by the overall control module.

[0103] During the spreading process, the second end of the filter cloth 71 is fixed on the bottom plate 21. When the cloth is pushed, in the vertical direction, the cloth pushing and spreading device 2 is located above the top of the first side wall of the filter cylinder 2 and between the second cloth guide rollers 73. During the movement from the first side wall to the second side wall, the cloth pushing and spreading device 2 pushes the filter cloth to move together and spreads the filter cloth on the bottom plate 21 of the filter cylinder 2.

[0104] A method for laying sludge on the above-mentioned sludge dewatering equipment includes: 1) the cloth rolling roller 7 starts to rotate and releases a section of the filter cloth rolled on the cloth rolling roller 7; when the first position sensor 74 detects the filter cloth, the cloth rolling roller 7 stops releasing the cloth; 2) the cloth pushing and spreading device 1 pushes the cloth to push the filter cloth 7 from the first side wall of the filter cylinder 2 to the second side wall, and during the cloth pushing process, sludge is sprayed onto the lower filter cloth 7 to complete the laying of a layer of sludge; 3) in the process of the cloth pushing and spreading device 1 moving from the second side wall of the filter cylinder 2 to the first side wall, the cloth rolling roller 7 rotates, and step 1) is repeated to release a section of filter cloth from the cloth rolling roller 7; 4) in the horizontal direction, the cloth pushing and spreading device 1 moves outside the filter cylinder, and the first cloth pressing assembly presses the filter cloth above the first side wall of the filter cylinder to the side wall at the top of the filter cylinder; steps 2)-4) are repeated in sequence.

[0105] This method of laying sludge has high sludge laying efficiency, thereby improving the overall dehydration efficiency.

[0106] In this embodiment, the specific structure of the cloth pushing and spreading device 1 is as follows:

[0107] As attached Figure 3 As shown, the cloth spreading device 1 includes a shell 11 and a mud spreading component 12 arranged in the shell 11, and the mud spreading component 12 includes a first component 121 and a second component 122. The first component 121 and the second component 122 both have channels for the mud to flow.

[0108] The first end 1211 of the first component 121 is connected to the third component 123 for conveying sludge, and the second end 1212 of the first component 121 is connected to the second component 122. The other end of the second component 122 is provided with a discharge port 1221, and the other end is arranged in an arc shape, and the discharge port is arranged downward. Alternatively, the first component and the second component are an integrated structure, or the first, second, and third components are an integrated structure.

[0109] A specific implementation method is shown in the attached Figure 1 As shown, the cross section of the first component 121 channel at the first end 1211 is circular or quasi-circular, and it is connected to the channel of the third component 123. The cross section at the second end 1212 of the first component 121 channel is rectangular. The horizontal direction perpendicular to the sludge flow direction is the width of the channel, and the vertical direction perpendicular to the sludge flow direction is the height of the channel. From the first end 1211 to the second end 1212 of the first component 121, the width of the first component 121 channel gradually increases, and the height of the channel decreases. The cross-sectional area of ​​the second end of the first component 121 channel is 0.7-1 times the cross-sectional area of ​​the first end.

[0110] In the sludge flow direction, the ratio of the length of the first component 121 to the width of the second end of the first component is 1:0.6-1:3, and the ratio of the length of the first component 121 to the second component 122 is 1:0.5-1:8.

[0111] As attached Figure 4 As shown, four groups of mud spreading components 12 can be arranged side by side in the housing 11, and the discharge ports 1221 of the mud spreading components 12 are located on the same straight line. The mud can be evenly distributed on the filter cloth. The third component 123 of the mud spreading component 11 passes through the second end of the housing, and the discharge port of the second component 122 is close to the first end of the housing.

[0112] The structure of the mud spreading assembly of the cloth pushing and spreading device 11 of this embodiment can evenly spread the mud on the filter cloth when the mud speed is fast, and the mud thickness difference is less than 1mm. This is combined with the low resistance and fast cloth pushing and spreading filter cloth of this application to improve the sludge laying efficiency.

[0113] In some examples, the specific structure of the housing 11 is shown in the attached Figure 4-8 The shell has a space for accommodating the mud spreading assembly, and a spreading opening 1121 is provided at the bottom of the shell 11, near the first end of the shell. The discharge opening 1221 of the mud spreading assembly 11 coincides with the spreading opening 1121 in a direction perpendicular to the bottom of the shell. The first end of the shell 11 is provided with a cloth pushing head 113 extending obliquely downward, and the first end of the cloth pushing head 113 is connected to the first end of the shell 11. During the cloth pushing process, the second end of the cloth pushing head 113 opposite to the first end is lower than the spreading opening 1121.

[0114] The cloth pushing head 113 can be an integrated structure with the housing 11; or, the cloth pushing head 113 and the housing 11 are separate structures, and the cloth pushing head 113 can be rotatably connected to the first end of the housing 11 through a connecting piece. The cloth pushing head 113 includes a cloth pushing column 1134, a rear plate and a first support plate 1131, and a second support plate 1132; one end of the first and second support plates are respectively connected to the circular periphery of the cloth pushing column 1134, and the second end is connected to the opposite sides of the rear plate. The first and second support plates are respectively tangent to the outer peripheral wall of the cloth pushing column 1134. The rear plate of the cloth pushing head 113 is connected to the housing 11.

[0115] Optionally, a reinforcing plate 1133 is provided between the two supporting plates.

[0116] The cloth pushing head 113 has two working states. First, during the cloth spreading process, the cloth pushing column 1134 of the cloth pushing head 113 rotates downward to the second position, the second position is lower than the spreading opening, and the distance between the second position and the spreading opening is greater than the thickness of the sludge to be laid. Second, after laying the filter cloth, when retreating, the cloth pushing head 113 includes a first position that rotates upward to the upper limit, and the cloth pushing head 113 is in the first position higher than the upper surface of the sludge to be laid.

[0117] In this embodiment, a structure for driving the cloth pushing head 113 to rotate between the first position and the second position may be provided between the cloth pushing head 113 and the housing 11 .

[0118] In this embodiment, the cloth pushing head 113 can be driven to rotate by a separate small motor. An elastic member, such as a torsion spring, can also be used to drive the cloth pushing head 113 to rotate to the first position.

[0119] In some specific embodiments, the cloth pushing head 113 is installed at the first end of the housing 11 via a rotating shaft, and the axis of the rotating shaft extends in a lateral direction perpendicular to the sludge flow direction. A limiting structure is provided between the cloth pushing head 113 and the housing 11 for limiting the upper limit position of the upward rotation of the cloth pushing head 113 and the upper limit position of the downward rotation.

[0120] The limiting structure can be arranged between the rotating shaft and the sleeve on the cloth pushing head 113. The limiting structure includes a first limiting structure and a second limiting structure, wherein the first limiting structure limits the upper limit position of the cloth pushing head 113 when rotating upward, and limits the cloth pushing head 113 to the first position, and the second limiting structure limits the upper limit position of the cloth pushing head 113 when rotating downward, and limits the cloth pushing head 113 to the second position.

[0121] In some other possible embodiments, the rotation of the cloth pushing head 113 can be limited by the front end surface of the shell 11. Specifically, the rotating shaft can be set between the middle of the first end surface of the shell 11 and the cloth pushing head 113, and there is a gap between the rear plate of the cloth pushing head 113 and the shell 11 for the cloth pushing head 113 to rotate. When the cloth pushing head 113 rotates to the first position, the upper end of the cloth pushing head 113 close to the shell 11 abuts against the front end of the shell 11, and when the cloth pushing head 113 rotates to the second position, the lower end of the cloth pushing head 113 close to the shell 11 abuts against the front end of the shell 11.

[0122] Preferably, in this embodiment, an elastic member is provided between the cloth pushing head 113 and the housing 11, and the elastic member is used to drive the cloth pushing head 113 to rotate toward the first position. During the forward feeding of the housing 11, the reaction force applied by the filter cloth 71 to the cloth pushing head 113 is greater than the elastic force of the elastic member, and the cloth pushing head 113 rotates toward the second position under the driving force of the reaction force of the filter cloth 71. Thus, the cloth pushing head 113 can be automatically switched between the first position and the second position, and can match the cloth pushing and spreading action of the housing 11.

[0123] As an optional solution, when the cloth pushing head 113 rotates to the first position, the height of the axis of the cloth pushing column 1134 is lower than the height of the rotation center of the cloth pushing head 113, thereby ensuring that the cloth pushing head 113 can rotate smoothly to the second position under the reaction force of the filter cloth 71.

[0124] Example 2

[0125] The configuration of this embodiment is basically the same as that of the embodiment 1, except that in the vertical direction, a second position sensor 76 is provided before the first position sensor 74 and the third position sensor 75. Fig. 9 shown.

[0126] In some embodiments, the first, second and third position sensors are proximity sensors (such as electromagnetic, electro-optical, capacitive, reed switch, Hall, etc.) The first, second and third position sensors are all arranged below the filter cloth 71 between the cloth winding roller 7 and the first cloth guide roller 72 .

[0127] During operation, the rotation speed of the cloth rolling roller 7 has nothing to do with the operating state of the cloth pushing and spreading device 1, as long as the lowest point of the filter cloth released from the cloth rolling roller is between the second position sensor 76 and the first sensor 74. Specifically, the best working state is: during the entire spreading process, by controlling the rotation speed of the cloth rolling roller 7, the first position sensor 74 can be unable to detect, and the second position sensor 76 always keeps detecting the filter cloth. In this state, the filter cloth 71 pushed by the cloth pushing and spreading device 1 is always in a relaxed state. When the third position sensor 75 cannot detect the filter cloth 71, the filter cloth released by the cloth rolling roller 7 is about to be in a tensioned state, and some components may fail.

[0128] Experimental Example 1

[0129] This experimental example is in the attached Figure 1 The method for laying sludge on the sludge dewatering device shown in the figure, the sludge laying component in the push cloth laying device is as shown in the attached Figure 3 As shown, the length of the first component 121 is 300 mm, and the channel cross-sectional area at the first end is 25 cm 2 , the length at the second end is 200mm and the width is 10mm; the length of the second component 122 is 330mm; the cross-section of the top of the filter cylinder is a square with an inner side length of 800mm.

[0130] The method for laying sludge in this experimental example includes: 1) starting the cloth roller to rotate, and after the filter cloth rolled on the cloth roller is released for 1.7 meters, the cloth roller stops releasing the cloth; 2) the cloth pushing and spreading device pushes the filter cloth from the first side wall of the filter cylinder to the second side wall at a first speed of 0.25 m / s. During the cloth pushing process, the sludge moves at a speed of 0.02 L / (s·cm 2) speed to the lower filter cloth, completing the laying of a layer of sludge; 3) the cloth-pushing and spreading device moves from the second side wall of the filter cylinder to the first side wall at a second speed of 0.5 m / s. During this process, step 1) is repeated to release 1.7 meters of filter cloth from the cloth roller; 4) in the horizontal direction, the cloth-pushing and spreading device moves outside the filter cylinder, and the first cloth-pressing assembly presses the filter cloth above the first side wall of the filter cylinder to the top of the filter cylinder; steps 2) - 4 are repeated in sequence. 100 layers of sludge are laid within 810 s. The thickness of each layer of sludge on the filter cloth is about 10 mm, and the thickness of the sludge on the entire filter cloth is within 1 mm.

[0131] In this experimental example, the adhesion stress of the sludge is 600Pa and the water content is 82%.

[0132] Comparative Example 1

[0133] The sludge dewatering equipment and sludge laying method of this comparative example are basically based on Experimental Example 1, but the difference is that the sludge laying method does not perform step 1), and does not spray sludge when pushing the cloth, but sprays sludge when retreating. Specifically:

[0134] 1) The cloth pushing and spreading device pushes the filter cloth to move from the first side wall of the filter cylinder to the second side wall at a first speed of 0.2 m / s;

[0135] 2) The cloth spreading device moves from the second side wall of the filter tank to the first side wall at a second speed of 0.25 m / s. During this process, the sludge moves at a speed of 0.02 L / (s·cm 2 ) speed to the lower filter cloth to complete the laying of a layer of sludge;

[0136] 3) In the horizontal direction, the cloth pushing and spreading device moves out of the filter cylinder, and the first cloth pressing assembly presses the filter cloth above the first side wall of the filter cylinder to the top of the filter cylinder; and steps 1) to 2) are repeated in sequence.

[0137] 100 layers of sludge were laid in 1065 seconds. The thickness of each layer of sludge on the filter cloth was about 10 mm, and the thickness of the sludge on the entire filter cloth was within 1 mm. In step 1), the first speed was significantly lower than the second speed of Experimental Example 1 due to the resistance of the tensioned filter cloth to the cloth-pushing device. In step 2), the second speed was also much lower than the second speed of Experimental Example 1 in order to match the sludge ejection speed and the thickness of each layer of sludge.

[0138] Comparative Example 2

[0139] The sludge dewatering equipment and the method for laying sludge in this comparative example are basically based on Experimental Example 1, except that the structure of the sludge laying assembly is different.

[0140] The mud paving components of this comparative example are shown in the attached Fig.10As shown, the cross-sectional area of ​​the first component 1-1' along the sludge flow direction gradually increases. On the vertical plane perpendicular to the sludge flow direction, the height of the channel remains basically unchanged, and the width in the horizontal direction perpendicular to the sludge flow direction gradually increases. The first component 1-1' is connected to the second component 1-2' at the first end, and is connected to the third component 1-3' at the second end. The cross-sectional area of ​​the channel of the first component 1-1' at the first end is 50cm 2 , the second end cross-sectional area is 20cm 2 ; The length of the first component 1-1' is 300mm, and the length of the second component 1-2' is 330mm.

[0141] The thickness of each layer of sludge on the filter cloth is about 10mm, and the thickness of sludge on the entire filter cloth varies by 2-3mm.

Claims

1. A method for laying sludge on a sludge dewatering device, comprising: 1) Before the cloth-pushing and spreading device pushes the cloth, the cloth-winding roller rotates to release a section of the filter cloth rolled on the cloth-winding roller; In the moving direction of the filter cloth, the length of the released filter cloth is greater than or equal to the length of the filter cloth laid on the bottom plate of the filter cylinder; When the first position sensor detects the filter cloth, the cloth roller stops releasing the cloth; 2) The cloth-pushing and spreading device pushes the filter cloth from the first side wall of the filter cylinder to the second side wall. During the cloth-pushing process, the sludge is sprayed onto the lower filter cloth to complete the laying of a layer of sludge; 3) When the cloth pushing and spreading device moves from the second side wall of the filter cylinder to the first side wall, the cloth rolling roller rotates and repeats step 1) to release a section of filter cloth from the cloth rolling roller; 4) In the horizontal direction, the cloth pushing and spreading device moves outside the filter cylinder, and the first cloth pressing assembly presses the filter cloth above the first side wall of the filter cylinder to the top of the filter cylinder; repeat steps 2) - 4) in sequence; The filter cloth released from the cloth rolling roller is in a V shape, and in the cloth pushing working state, the lowest part of the V shape moves between a first position and a third position below the cloth rolling roller and the first cloth guide roller, wherein in the vertical direction, the first position is lower than the third position; The sludge dewatering equipment comprises: a cloth pushing and spreading device and a filter cloth winding and unwinding device; the filter cloth winding and unwinding device is arranged on one side of the filter cylinder, the cloth pushing and spreading device is arranged above the filter cylinder, and moves back and forth in the horizontal direction of the side where the filter cloth winding and unwinding device is arranged; the filter cloth winding and unwinding device comprises a cloth winding roller and a plurality of cloth guide rollers, the filter cloth is wound on the cloth winding roller, and the first end of the filter cloth is located in the filter cloth roll; in the cloth pushing working state, the second end of the filter cloth is arranged and fixed on the bottom plate in the filter cylinder, and the length of the filter cloth between the cloth winding roller and the first cloth guide roller in the moving direction of the filter cloth is greater than the straight-line distance between the cloth winding roller and the first guide roller; A first position sensor and a third position sensor are provided on the filter cloth winding device, the first position sensor is used to sense whether the lowest part of the filter cloth is at the first position, and the third position sensor is used to sense whether the lowest part of the filter cloth is at the third position; During the whole spreading process, the rotation speed of the cloth rolling roller is adjusted so that the lowest part of the filter cloth released from the cloth rolling roller is located between the first position and the second position; In the vertical direction, the second position is located between the first position and the third position; The second position sensor arranged on the filter cloth winding device is used to sense whether the lowest part of the filter cloth is in the second position.

2. The method according to claim 1, characterized in that: The first speed at which the cloth-pushing and spreading device moves from the first side wall to the second side wall of the filter cylinder is lower than the second speed at which the cloth-pushing and spreading device moves from the second side wall to the first side wall of the filter cylinder; The filter cloth is laid and the sludge is sprayed during the movement from the first side wall to the second side wall.

3. The method according to claim 1 or 2, characterized in that: The cloth-pushing and spreading device includes a shell and a mud-spreading component arranged in the shell, and the mud-spreading component includes: a first component and a second component respectively having channels, the second end of the second component is provided with a discharge port, the second end of the first component is connected to the first end of the second component, so that the first component channel is connected to the second component channel; the cross-section of the channel of the second component is the same in a direction perpendicular to the forward direction of the sludge, and the bottom surface of the second component supporting the sludge is a plane; the cross-sectional area of ​​the first component channel at the second end is smaller than the cross-sectional area at the first end, and the cross-sectional area of ​​the second component channel is the same as the cross-sectional area of ​​the first component channel at the second end.

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