A screen and its forming process

Abstract

The present invention relates to the technical field of domestic waste treatment, and discloses a screen and a forming process thereof, including a screen body, wherein a plurality of mesh areas are arranged in zones on the screen body, and adjacent mesh areas are provided with spacing; the outer aperture of each mesh near the outer wall is larger than the inner aperture near the inner wall; two screen bodies with semicircular cross sections are arranged relative to each other to form a screen cylinder, and the high-pressure area of ​​the screw extruder corresponds to at least two screen cylinders. The mesh of the screen body is formed into a structure with a small inner aperture and a large outer aperture through a rolling and shaping process. The problem of high cost caused by frequent replacement of existing screens and complex processing of existing screens is solved, and the use of this technology to treat kitchen waste can reduce the solid content in the liquid phase, reduce the subsequent environmental burden, and open up a new path for more efficient, economical and environmentally friendly domestic waste treatment.

Description

Technical Field

[0001] The invention relates to the technical field of domestic waste treatment, and in particular to a screen and a forming process thereof. Background Art

[0002] Kitchen waste refers to the waste generated in residents' daily life and food processing, catering services, unit catering and other activities; when processing kitchen waste, a screw extruder will be used to continuously extrude the material to achieve solid-liquid separation. During the processing, the material is transported from the feed end to the high-pressure area at the rear end by the spiral main shaft. After being extruded in the high-pressure area, the solid phase is discharged from the slag outlet of the screen group, and the liquid phase is discharged from the filter holes on the screen group.

[0003] The screw extruder is further divided into an extruder with a variable diameter screw main shaft and a sliding screen. The screen aperture of this type of extruder is relatively large, which is suitable for materials with larger particle sizes. In addition, the prior art also has an extruder with a non-variable screw main shaft and an integrated screen structure. The aperture of this type of extruder is relatively small, 5 to 6 mm, and is suitable for extruding materials with smaller particle sizes. The kitchen waste in this technology is mainly extruded using the latter; such as Figure 1 As shown, a conventional screw extruder with an integrated screen structure comprises a feed port 41, a slag outlet 42 and an extrusion zone between the feed port 41 and the slag outlet 42, wherein a screen drum assembly is arranged in the extrusion zone, and the screen drum assembly comprises a screen drum 2, a mounting drum frame 3 and a machine body shell 4 which are sequentially sleeved from the inside to the outside, a screw shaft 31 (i.e., a spiral auger) is arranged in the screen drum 2, and a motor for driving the spiral auger is arranged at one end of the screen drum 2 close to the feed port 41, and a back pressure structure is arranged at one end of the screen drum 2 close to the slag outlet 42, and the back pressure structure comprises a back cone 4 driven by a hydraulic cylinder, and the extrusion pressure on the kitchen waste inside the screen drum 2 can be adjusted by controlling the telescopic degree of the back cone 4; the screen drum 2 comprises two half-type screens combined and the screens are welded and installed as shown in FIG. Figure 2 In the installation drum frame 3 shown, the installation drum frame 3 includes symmetrically arranged half drum frames, and the two half drum frames are fixed by passing bolts. Although the prior art can perform solid-liquid separation, the inventor still found the following problems in the actual production process: the screen is easy to deform, and the strength and wear resistance are poor, resulting in frequent replacement and increased maintenance costs. Summary of the invention

[0004] The present invention aims to provide a screen and a forming process thereof, so as to solve the problem of high cost caused by frequent screen replacement in the existing kitchen waste and domestic waste treatment process.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] A screen comprises a screen body, on which a plurality of mesh areas are arranged in zones, and adjacent mesh areas are provided with spacing; the outer aperture of each mesh near the outer wall is larger than the inner aperture near the inner wall, and the outer aperture is 2.1 mm ≤ ≤ 2.8 mm.

[0007] Preferably, as an improvement, two screen bodies with semicircular cross-sections are arranged opposite to each other and combined to form a screen cylinder; the screen cylinder is a segmented structure, and the high-pressure zone of the screw extruder corresponds to at least two segments of the screen cylinder.

[0008] Preferably, as an improvement, at least one end surface of the screen body is provided with a plurality of U-shaped through grooves, which are used as welding points for welding the screen body to the mounting drum frame.

[0009] Preferably, as an improvement, the spacing a between adjacent mesh areas is 12 to 12.5 mm.

[0010] Preferably, as an improvement, the outer diameter of the mesh is 2.4-2.6 mm, and the inner diameter is 1.9-2.2 mm.

[0011] Preferably, as an improvement, the width b of the U-shaped through groove is 6 to 8 mm.

[0012] The present application also discloses a screen forming process, comprising the following steps:

[0013] Step 1: Process multiple mesh holes on the plate;

[0014] Step 2: bend and roll the plate with mesh processed in step 1 to form an arc structure with a semicircular cross-section and shape it into a screen body; the mesh of the screen body is formed into a structure with a small inner aperture and a large outer aperture through the rolling and shaping process.

[0015] Preferably, as an improvement, in step 2, the rolled screen body is shaped by using a mounting drum frame, and a shaping tool is installed on the screen body, the shaping tool includes an adjusting rod, and the adjusting rod includes a left end rod, a right end rod and a connecting rod threadedly connected between the left end rod and the right end rod;

[0016] The shaping method is as follows: when using a shaping tool to shape the rolled sheet, the rolled sheet is placed in the installation drum frame, at least two adjustment rods are welded at intervals inside the screen body, and the length of the adjustment rod is adjusted by twisting the screw on the adjustment rod so that the two ends of the adjustment rod can press the screen body tightly against the inner wall of the installation drum frame.

[0017] Preferably, as an improvement, in step one, mesh holes are processed on a wear-resistant steel plate having a thickness of 5 to 6 mm by laser drilling.

[0018] Preferably, as an improvement, in step 1, the mesh aperture R processed on the plate is 2-2.5 mm.

[0019] Invention concept:

[0020] 1. The inventors have found that the areas where the existing screens are prone to deformation are mainly concentrated in the high-pressure area. After analysis, it may be due to the large extrusion pressure in the high-pressure area, and the circumferential edges of the mesh and the edges of the two ends of the screen are prone to wear and deformation. In order to solve the problems of screen strength and wear resistance in the prior art, the inventors pioneered the reduction of the aperture of the screw extruder screen, in order to increase the strength of the entire screen by increasing the interval between adjacent meshes. However, during the research and development process, the inventors found that the aperture of the screw extruder screen for kitchen waste in this field is generally 5-6mm, and the mesh with a smaller diameter cannot be made. The main reason is the particularity of kitchen waste. Kitchen waste usually refers to food waste generated in residents' daily lives, such as leftovers, fruit peels, and vegetable residues generated in family kitchens. These wastes come from thousands of households and are huge in quantity; our company uses a combination of anaerobic digestion + incineration to treat kitchen waste, and the materials output from the anaerobic tank are dehydrated by a screw extruder and then incinerated. After the kitchen waste is treated by anaerobic digestion, although some organic matter is decomposed and transformed, the remaining material still contains a lot of fiber, soft tissue and incompletely decomposed food residues. These substances are more likely to entangle together or adhere to the screen when passing through the screw extruder, especially when the mesh size is further reduced, causing the extruder to be blocked. In addition, although smaller apertures can theoretically improve dehydration efficiency and dry matter recovery rate, they will also increase the operating burden and maintenance cost of the equipment. Finer mesh means that greater extrusion force is required, which not only requires higher mechanical strength and power consumption, but may also accelerate the wear of the screen and shorten its service life. At the same time, fine meshes are more easily clogged by fine impurities, and the difficulty and frequency of cleaning will increase, affecting continuous and stable operation. Therefore, there is a big contradiction between increasing the interval between each mesh and improving the strength of the entire screen cylinder by directly reducing the mesh aperture.

[0021] Therefore, in order to solve the above problems, the inventor changed the original integrated screen drum structure into a segmented structure, distinguished between high-pressure and low-pressure areas, and dispersed the pressure in the corresponding areas. Even if there is a problem with the screen drum in the high-pressure area, only part of it needs to be replaced, thereby reducing the high cost caused by frequent integrated replacement.

[0022] However, in order to further eliminate the problem from the root, the inventor continued to conduct multiple experimental studies on the basis of the above, and designed each mesh to be a small inside and large outside structure. At the same time, the inventor also designed the mesh in different areas, so that multiple meshes are concentrated together to form a mesh area, and reserved spacing between adjacent mesh areas; after experimental comparison, the original screen was severely deformed after one month of use and basically needed to be replaced, while the screen body using this technology was used for one month, and the cylinder wall of the screen body was still flat, and the effect was significant. After analysis, the main reasons are as follows: if there is material stuck in the mesh during use, under the force of the spiral main shaft squeezing the material, the material stuck in the filter hole can easily fall off in the direction of the large aperture of the outer wall, thereby improving the water filtration efficiency of the material, reducing the risk of blockage, and improving the processing efficiency; at the same time, the reserved spacing between the mesh areas acts as a reinforcing rib, which further enhances the strength of the screen body on the original basis, and basically solves the problem of deformation of the screen body in a short period of time. In summary, the original mesh structure design causes the material to squeeze the mesh edge during extrusion, which in turn causes the mesh to deform easily. After the improvement of this technology, the force of the material squeezing the mesh edge is reduced and dispersed, while also increasing the strength of the single-section cylinder, thereby reducing the deformation of the screen body.

[0023] 2. In order to further reduce the processing cost, the inventor found that if the mesh is designed to be a small inside and large outside structure, since the thickness of the screen is relatively thin (about 6 mm), if the existing countersunk hole tool is to form the hole, it must use a needle-like tool head for hole processing, which is easy to break; in addition, the inventor has adopted a method of first drilling a small-diameter through hole in the plate, and then drilling a large-diameter hole near the outer wall of the through hole, and then processing to form a countersunk hole-like structure; however, during the processing, the inventor found that punching twice was rather cumbersome, so a breakthrough improvement was made in the screen forming process, and a new screen forming process was designed, which changed the original screen that required two punchings to only require one punching, and then the screen was rolled and formed during the process of forming the mesh so that the mesh naturally formed a mesh structure with a small inner diameter and a large outer diameter, which ultimately met the screen filtration requirements.

[0024] Beneficial effects:

[0025] 1. This technology combines the design of small inside and large outside mesh and the mesh partition design, which not only solves the problem of shortened service life of traditional screen mesh after the mesh becomes smaller, but also reduces the environmental pollution caused by kitchen waste treatment and reduces the subsequent treatment costs. It has a profound impact on the field of kitchen waste treatment and has a breakthrough impact on the kitchen waste treatment of the entire city and even the country; especially in reducing environmental pollution and reducing subsequent treatment costs. The improved screw extruder screen aperture is reduced to 3mm and below, which means that in the process of kitchen waste treatment, the liquid phase and solid phase can be separated more finely, thereby greatly reducing the solid content in the liquid phase to a level below 9%, reducing the burden of the subsequent treatment stage, as follows:

[0026] (1) For the subsequent liquid phase centrifuge centrifugal treatment stage, the original solid content in the liquid phase was 12-15%, which means that the centrifugal efficiency will be affected and the wear on the drum will be greater. After adopting this technology, the solid content in the liquid phase is reduced to less than 10%, which improves the treatment efficiency and service life of the centrifuge;

[0027] (2) For the subsequent sewage treatment stage, the use of this technology to pre-treat food waste can reduce the solid content in the early liquid phase and reduce the energy consumption and chemical consumption in the subsequent treatment stage. For example, reducing the use of flocculants in the sewage treatment process means reducing the input of chemicals, which not only reduces costs, but also reduces chemical residues in the treatment process, reduces the negative impact of the treatment process on the environment, and improves the effluent water quality, which helps to achieve a more environmentally friendly and sustainable food waste treatment solution and ensure the comprehensive utilization of wastewater; less floc formation reduces the load on the sedimentation tank or filtration unit, improves the treatment efficiency, and reduces the frequency of maintenance and cleaning, thereby reducing the overall operating cost;

[0028] Overall, this technology can not only reduce chemical consumption and energy use in the subsequent treatment stages, but also reduce equipment maintenance and replacement costs, thereby significantly saving costs in long-term operations, improving economic benefits and reducing negative impacts on the environment.

[0029] 2. The screen cylinder structure formed by the screen mesh using this technology has good performance and can reduce maintenance and replacement costs:

[0030] Compared with the screw extruder in the prior art in which the screen cylinder is an integrated structure or the corresponding screen cylinder of the screw extruder is designed as an integrated structure, experiments have found that the screen cylinder formed by the screen body of the present technology and the screen cylinder is placed in the screw extruder with a multi-stage structure design, especially with at least two sections of screen cylinder corresponding to the high-pressure area of ​​the screw extruder, can further reduce the deformation problem of the screen cylinder. Analysis shows that the main reason is that the present technology shortens the length of the screen in the high-pressure area, which not only adjusts the force of the entire interior, but also makes the deformation of the local area of ​​the plate surface more controllable during the plate processing, so that the screen can fit better with the mounting drum frame; if the fit is not good, the kitchen waste material will rotate during the contact with the screen, which is more likely to cause the screen to deform.

[0031] Furthermore, this technology sets the screen drum as a segmented structure, which not only combines the advantages mentioned above, but also the split structure allows the screen in the high-pressure area to be divided into zones. When the wear is severe, only part of the high-pressure section of the screen needs to be replaced, rather than the entire screen body, which significantly reduces maintenance costs and downtime. The segmented design facilitates quick positioning of the worn area, making repair or replacement work easier and faster, reducing maintenance complexity and improving equipment availability and production efficiency. Furthermore, at least two sections of the screen drum are located in the high-pressure area, which not only reduces screen deformation, but also reduces replacement costs.

[0032] 3. The design of U-shaped groove has the following advantages:

[0033] 1. Ensure better fixing effect: The inner edge surface of the U-shaped groove can fully contact with the solder, thereby achieving better fixing.

[0034] 2. Convenient for welding operation: Compared with the case without U-shaped groove, the design of U-shaped groove provides clear operation guidance for welding workers, making welding operation more convenient and standardized, and helping to improve the accuracy and consistency of welding.

[0035] 3. Easy to repair and replace: Once the screen needs to be repaired or replaced, the U-shaped groove design also makes it easier to disassemble and reinstall, because the structure of the welding area is more clear, reducing the risk of damage to the surrounding structure.

[0036] 4. The U-shaped through-groove design can guide the thermal stress and mechanical stress generated by welding to disperse along the groove shape, avoid stress concentration, reduce the damage of local excessive stress to the welding joint and the parent material, improve the fatigue resistance of the entire structure, and extend the service life of the equipment.

[0037] 5. Aesthetics: From the appearance point of view, the design with U-shaped welding groove makes the equipment look more neat and professional. It is also conducive to the standardized production of equipment and facilitates the subsequent interchange and upgrading of parts.

[0038] 6. The width b of the U-shaped through groove is 6-8mm, which can provide a larger contact area for welding, thus increasing the filling amount of welding materials, thereby improving the overall strength and pull-off resistance of the welding part. The existence of the welding groove allows the weld to penetrate deeper into the material, forming a stronger mechanical lock and reducing the probability of welding cracks and defects.

[0039] If the slot width of the U-shaped through slot is less than 6mm, the smaller slot width means that the welding space is limited, which makes the welding operation difficult, especially during manual welding, when the arc or welding rod is difficult to accurately enter the slot, resulting in a decrease in welding quality, and may cause incomplete welding and increased weld defects. Narrow slots may result in insufficient welding metal filling and thin welds, which will weaken the strength and toughness of the welded joint and increase the risk of fracture and falling off, especially under conditions of high stress, which can easily lead to equipment failure. If the slot width is too small, the heat will be concentrated in a smaller area during welding, which can easily cause local overheating, causing thermal deformation of the welding area and surrounding materials, and affecting the stability of equipment operation. When the slot width of the U-shaped through slot is greater than 8mm, the inventor found that when the welding area is disassembled in the later stage, it is easy to cause damage or deformation to structures such as the mounting barrel rack, affecting the performance of the overall machine. Therefore, the use of this slot width can not only meet the requirements of welding strength and durability, but also facilitate actual operation and maintenance.

[0040] 4. The spacing area between adjacent mesh areas corresponds to the frame reinforcement of the installation drum frame, and the mesh area corresponds to the hollow area of ​​the installation drum frame; the filtration surface of the screen body after the mesh area is improved will not be affected, thereby ensuring the filtration efficiency and effect.

[0041] Each screen body adopts a method of arranging mesh holes in different areas, and controls the spacing a between adjacent mesh areas to be 12mm to 12.5mm, which can further improve the strength of the screen body and increase the service life of the entire equipment.

[0042] 5. Since the screen body is used in high-pressure scenarios, as the kitchen waste material is pushed forward by the spiral, the outer aperture is set to 2.1-2.8 mm, the optimal setting is 2.4-2.6 mm, and the inner aperture is 1.9-2.2 mm, which helps to reduce the direct impact of solid materials on the screen, distribute the pressure, and improve the durability of the screen. At the same time, this design also helps the solid particles or fiber materials in the material to pass through the screen more smoothly, reduce blockage, and facilitate cleaning and maintenance. The difference in the inner and outer apertures helps to form a certain pressure gradient to ensure the separation effect.

[0043] 6. The forming process of the screen using this technology has the following advantages:

[0044] 1. Precise control of aperture: Laser drilling technology can control the diameter of the hole extremely accurately, ensuring the consistency and accuracy of each aperture, and even very small holes can achieve high precision.

[0045] 2. Simplify the process flow: It is difficult to accurately process a screen with such a small aperture using traditional milling. Generally speaking, through holes are processed first, and then large-aperture holes are processed on the outside of the screen to form a structure with a large outside and a small inside. However, using this process, the screen only needs two steps: laser drilling and rolling to finalize the shape. The inner aperture of the inner wall of the screen can automatically form a structure with a small inner aperture and a large outer aperture during the rolling process.

[0046] That is to say, differentiated apertures can be automatically formed: the inventor cleverly utilizes the natural extension and deformation of the screen material during the rolling and shaping process. For example, a hole structure with an inner diameter of about 2mm and an outer diameter of about 2.5mm can be automatically formed without secondary processing. Therefore, this technology abandons the traditional cumbersome process of step-by-step processing of inner and outer apertures, and automatically forms the required inner and outer apertures through one-time laser drilling combined with the rolling and shaping steps. This not only reduces the processing steps and reduces the manufacturing complexity; at the same time, the mounting drum rack is used to shape the screen body, which is very convenient and saves process flow.

[0047] 3. Improve material utilization and yield rate: Compared with the material waste and high scrap rate that may be caused by milling, the laser processing combined with the rolling shaping process is more efficient, reduces material loss, and is conducive to cost control and environmentally friendly production.

[0048] In summary, the inventor's innovative screen structure and molding process effectively solve the problems of screen deformation and high solid content in the liquid phase during kitchen waste treatment, significantly improve the life of the screw extruder screen drum, and not only reduce maintenance costs; but also use this technology to pre-treat kitchen waste, which can reduce the solid content in the early liquid phase and reduce the subsequent environmental burden. The new process accelerates screen production, reduces costs, and promotes the efficiency and economy of kitchen waste treatment as a whole. It has made significant contributions to the progress of the industry and promoted resource recycling and environmental protection. This technological innovation has opened up a new path for more efficient, economical and environmentally friendly domestic waste treatment.

[0049] 7. Use the shaping tool to shape the screen body after rolling, which can eliminate the stress after rolling and avoid rebound, thus playing a role in solidification; at the same time, in the initial stage of shaping, the plate can be adjusted by adjusting the pull rod to tighten it, so that it can be installed close to the inner wall of the drum frame. It is worth mentioning that this shaping tool can also be used in the subsequent screen docking installation process, and fine-tuning can be performed by adjusting the pull rod to facilitate the precise docking and installation of the two semi-arc screen bodies. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a schematic structural diagram of an integrated screen drum in a screw extruder in the background technology.

[0051] Figure 2 for Figure 1 Schematic diagram of the structure of the cylinder rack installed in.

[0052] Figure 3 This is a top view of the plate after laser drilling.

[0053] Figure 4 for Figure 3 A partial enlarged view of middle A.

[0054] Figure 5 It is a schematic diagram of the structure of the installation drum rack with the screen placed.

[0055] Figure 6 for Figure 5 Top view of the middle screen body.

[0056] Figure 7 To install the screen Figure 2 Front view of the mounting cartridge in the holder.

[0057] Figure 8 for Figure 7 Front view of the middle screen cylinder.

[0058] Fig. 9 This is a schematic diagram of the structure of the screw extruder in Example 1 of the present invention.

[0059] Fig.10 for Fig. 9 Exploded view of the cylinder holder installed in.

[0060] Fig.11 for Fig.10 Schematic diagram of the upper-middle half-tube frame.

[0061] Fig.12 Comparative Example 7: An integrated screen installed in a screw extruder and used for one month.

[0062] Fig.13 This is a graph showing a screen formed using Example 1 installed in a screw extruder and used for one month. DETAILED DESCRIPTION

[0063] The following is further described in detail through specific implementation methods:

[0064] The marks in the drawings of the specification include: screen body 11, U-shaped through groove 111, pressure plate gap 112, mesh area 12, screen cylinder 2, mounting cylinder frame 3, spiral shaft 31, half cylinder frame 32, semi-ring frame rib 321, eight-shaped reinforcement rib 322, axial tension rib 323, bolt column 324, pressure plate 33, partition 34, clamping protrusion 341, body shell 4, feed port 41, slag outlet 42, liquid outlet 43, back cone 44, motor 45, machine cover 5, left end rod 61, right end rod 62, connecting rod 63, limiting ear groove 64, material guide half cylinder frame 7.

[0065] Example 1

[0066] like Figure 1-13 As shown, a screen forming process includes the following steps:

[0067] Step 1: Cut the wear-resistant steel with a thickness of 5-6 mm into rectangular plates. In this embodiment, the preferred plate is 6 mm thick NM400 wear-resistant steel plate with a tensile strength of ≥1200 MPa, a yield strength of ≥800 MPa, an elongation of ≥10%, and an impact toughness of ≥24 J. The length of one side of the plate after cutting is B. 1 =500~550mm, the other side length is B 2 450-500 mm, in this embodiment B 1 =548mm, B 2 =494mm; laser drilling is used to perform the first drilling process on the plate in different areas to form multiple square mesh areas 12, each mesh area 12 includes multiple rows of mesh holes arranged along the axial direction, and adjacent rows of mesh holes are staggered; the first drilling diameter of each mesh hole R = 2 to 2.5mm, and the specific processing in this embodiment is 2.3mm. Specifically, combined with Figure 3 , 4 As shown, radially speaking, the distance d between the centers of adjacent meshes in the same row is 3.5-4.5 mm, and specifically 3.7 mm in this embodiment; the distance e between the centers of adjacent offset meshes in adjacent rows is d*1 / 2, and specifically 1.85 mm in this embodiment. Looking at two adjacent rows of meshes along the axial direction, the line connecting any one mesh in each row and the center of the circle of two adjacent meshes forms an equilateral triangle, the distance f between the centers of adjacent meshes in the same row is the height of the equilateral triangle*2, and f is 6.4 in this embodiment, and the distance g between the centers of adjacent offset meshes in two adjacent rows is the height of the equilateral triangle, and specifically 3.2 mm in this embodiment. The spacing a between adjacent mesh areas 12 is 12-12.5, and specifically 12.5 mm in this embodiment. It is easy to roll into a round shape, and while ensuring strength, it will not reduce the water filtration area compared to the original one-piece screen.

[0068] Step 2: Place the plate with mesh processed in step 1 along the side length B 1 direction (i.e., Figure 3 The vertical direction) is bent and rolled to form an arc structure with a semicircular cross section and shaped as follows Figure 5 The mesh body 11 shown in the figure; the mesh of the mesh body 11 is formed into a structure with a small inner aperture and a large outer aperture through a rolling and shaping process. The specific process is as follows:

[0069] Rolling: A plate rolling machine is used to roll the plate to form the screen body 11. The rolling speed is 8 to 12 revolutions per minute, and the specific embodiment is 10 revolutions per minute. The diameter of the rolling shaft is 360 to 370 mm, and the specific embodiment is 365 mm. The inventors have found through experiments that the forming effect can be guaranteed if the diameter of the rolling shaft is controlled within the above range. In addition, if the rolling speed is lower than 8 revolutions per minute, it may lead to problems such as increased forming time and mesh deformation; if the rolling speed is higher than 12 revolutions per minute, it will lead to unstable forming and excessive mesh deformation; controlling the number of revolutions within this range can ensure the quality of rolling.

[0070] Shaping: The rolled screen body 11 is shaped by installing the drum frame 3, and a shaping tool is provided inside the screen body 11. The shaping tool includes: Figure 4 The adjustment rod shown in the figure includes a left end rod 61, a right end rod 62 and a connecting rod 63 threadedly connected between the left end rod 61 and the right end rod 62. A screw is welded to one end of the left end rod 61 close to the connecting rod 63, and the annular buckle at the end of the screw is welded to the left end rod 61. One end of the right end rod 62 is hook-shaped, and the other end is a screw. A strip through hole is provided in the middle of the connecting rod 63, and axial threaded holes are provided at both ends of the connecting rod 63. The screws on the left end rod 61 and the screws on the right end rod 62 are respectively extended into the axial threaded holes and threadedly connected thereto; the strip through hole is mainly convenient for checking the extension of the screws on the left end rod 61 and the screws on the right end rod 62. In other embodiments other than this embodiment, a limiting ear groove 64 is also provided on the back of the mounting barrel frame 3, which is convenient for positioning and matching with the protrusions on the equipment during subsequent installation to achieve high-precision installation.

[0071] When the screen body 11 is shaped by the shaping tool, the rolled screen body 11 is placed in the installation drum frame 3; the adjusting rods are welded on the upper and lower parts of the screen body 11 respectively. In other embodiments other than the present embodiment, the adjusting rods can also be welded on the upper, middle and lower parts, or more adjusting rods are welded, which all belong to the protection scope of the present invention; by twisting the screw on the adjusting rod, the length of the adjusting rod is adjusted so that the two ends of the adjusting rod can press the screen body 11 against the inner wall of the installation drum frame 3. Under natural conditions at room temperature, the adjusting rod is removed after 3 days, and in this embodiment, the adjusting rod is removed after 7 days; after measurement, the radius R of the final screen body 11 is 176.5, the outer aperture is about 2.5mm (2.4-2.6mm), and the inner aperture is about 2mm (1.9-2.2mm).

[0072] This embodiment also discloses a screen formed by the above process, such as Figure 5 , 6As shown, the screen body 11 includes a plurality of square mesh areas 12 enriched with mesh holes, and the spacing a between adjacent mesh areas 12 in the radial direction is 12-14 mm. In this embodiment, the spacing between adjacent mesh areas 12 in the radial direction is 12.5 mm, and the spacing between adjacent mesh areas 12 in the axial direction will increase by 0.3-1.5 on the basis of the spacing before processing due to the extrusion of rolling. Taking 12.5 before processing as an example, the spacing in the middle of the axial direction after rolling is 14 mm, and the spacing between the upper and lower axial directions is 12.8 mm.

[0073] The outer aperture of each mesh near the outer wall is larger than the inner aperture near the inner wall. For the sake of distinction, the aperture near the outer wall is called the outer aperture, and the aperture near the inner wall is called the inner aperture. The outer aperture is R+M. 1 , inner diameter is RM 2 ; R = 2 ~ 2.5mm, M 1 =0.1~0.3mm, M 2 =0.1-0.4mm. In this embodiment, taking R=2.3mm as an example, the outer aperture range after the rounding process is 2.4-2.6mm, and the inner aperture range is 1.9-2.2mm.

[0074] like Figure 5 As shown, the mesh area 12 includes multiple rows of mesh holes arranged along the axial direction, and adjacent rows of mesh holes are staggered. At least one end face of the screen body 11 is provided with multiple U-shaped through grooves 111. The lower end face of the screen body 11 of the present technology is provided with multiple U-shaped through grooves 111, which are used as welding points for welding the screen body 11 to the mounting drum frame 3; the groove width b of the U-shaped through groove 111 is 6 to 8 mm, and is specifically 6 mm in this embodiment; the groove depth k of the U-shaped through groove 111 is less than or equal to the groove width, and is specifically less than in this embodiment, k is 3 mm. As shown in FIG. Figure 6 As shown, compared with a perfect semicircle, the two end faces of the screen body 11 are lower than the diameter passing through the center of the circle, that is, the line between the two ends of the screen body 11 does not pass through the center of the circle, but is lower than the diameter passing through the center of the circle; and thus a pressure plate gap 112 is reserved, and the gap width in this embodiment is 7.5 mm, so as to reserve a gap for the pressure plate 33 that presses the screen during subsequent installation.

[0075] The above-mentioned screen mesh forms a screen cylinder, and two screen mesh bodies 11 with a semicircular cross section are relatively spliced ​​to form a screen cylinder 2, specifically, they are relatively spliced ​​using the mounting drum frame 3 of the screw extruder, and the screen cylinder 2 is welded in the mounting drum frame 3. The screen cylinder 2 is a segmented screen cylinder, which includes at least three segments, and at least two of them are located in the high-pressure area of ​​the screw extruder; this embodiment is specifically as follows Figure 8Taking the four-section screen drum as an example, two sections are located in the high-pressure area of ​​the screw extruder extrusion zone, and the other two sections are located in the low-pressure area of ​​the screw extruder extrusion zone. Among the four screen drums, the mesh area 12 on the screen body 11 of the screen drums 2 at both ends has an anti-deformation spacing between the end of the screen body 11, so that the mesh area 12 forms a certain distance with the end of the screen body 11 to avoid deformation of the end. Figure 3 Shown is Figure 8 In the schematic diagram of the plate at the leftmost end of the screw extruder before the screen body 11 is rolled up, it can be seen that an anti-deformation spacing h is set between the mesh area 12 at the left end of the screen body 11 and the end, and h is 20±1mm. Figure 2 The installation cartridge holder 3 shown in FIG. Figure 7 Status shown.

[0076] The axial direction referred to in this document refers to the central axis direction of the screen drum 2 of the screw extruder, which is also the conveying direction of the kitchen waste in the screen drum 2; the radial direction refers to the diameter direction of the screen drum 2.

[0077] In other embodiments besides this embodiment, a screw extruder equipped with a segmented screen drum is also disclosed, such as Fig. 9 , 10 The figure shows a feed port 41, a slag outlet 42 and an extrusion zone between the feed port 41 and the slag outlet 42. A screen drum assembly is arranged in the extrusion zone. The screen drum assembly includes a screen drum 2, a mounting drum frame 3 and a body shell 4 which are sequentially sleeved from the inside to the outside. A cover 5 is arranged at the body shell 4 corresponding to the extrusion zone. A spiral auger is arranged in the screen drum 2. There is a gap between the screen drum 2 and the spiral auger blades, and the spiral auger is driven to rotate by a motor 45 through a pulley. The screen drum 2 is installed in the mounting drum frame 3. The screen drum 2 in this embodiment is a segmented screen drum structure disclosed above, and each segment of the screen drum 2 includes two screen bodies 11 arranged oppositely. The spacing between adjacent mesh areas 12 corresponds to the frame ribs of the mounting drum frame 3, and the mesh area 12 corresponds to the hollow area of ​​the mounting drum frame 3.

[0078] The area where the back pressure of a traditional screw extruder is about 5 kilograms is a low-pressure area, and the rest is a high-pressure area. Through research, the inventor designed a segmented screen inside the screw extruder and re-divided the extrusion area. The low-pressure area is: the extrusion area corresponding to the back pressure of the screw extruder of 0 to 10 kilograms; and the high-pressure area includes two areas: the extrusion area corresponding to the back pressure of the screw extruder of 10 to 30 kilograms, and the extrusion area corresponding to the back pressure of the screw extruder of 30 to 50 kilograms.

[0079] When the segmented screen drum 2 has three sections, one section is located in the extrusion area corresponding to the back pressure of the screw extruder of 0 to 10 kg; one section is located in the extrusion area corresponding to the back pressure of the screw extruder of 10 to 30 kg; and the other section is set in the extrusion area corresponding to the back pressure of the screw extruder of 30 to 50 kg. When the segmented screen has four sections, there are two sections of the screen in the extrusion area corresponding to the back pressure of the screw extruder of 30 to 50 kg, and the other two sections are respectively set in the extrusion area corresponding to 0 to 10 kg and the extrusion area corresponding to 10 to 30 kg.

[0080] like Fig.10 As shown, the present embodiment also discloses a segmented installation of a drum rack, including a plurality of drum rack bodies connected to each other, with partitions 34 provided between adjacent drum rack bodies, the partitions 34 being bolted to the drum rack bodies, and the partitions 34 being a square structure formed by splicing upper and lower U-shaped frames, the middle parts of the upper and lower sides of the partitions 34 both protrude outward to form a clamping protrusion 341, and the surrounding areas of the partitions 34 protrude from the drum rack body; arc reinforcement ribs arranged around the partitions 34 are provided on the machine cover 5, and the partitions 34 can be clamped into the arc reinforcement ribs for fixation; arc reinforcement ribs are also correspondingly provided on the body shell 4 at the bottom of the extrusion zone, for clamping the lower partition 34 for fixation; therefore, the present technology utilizes the partitions 34 to make up the distance between the drum rack body and the body shell 4 and the machine cover 5, so that the entire drum rack body can be compressed and fixed when the machine cover 5 is closed. Fig.10 As shown, in this embodiment, three drum rack bodies are specifically taken as an example. The drum rack body at the left end is connected to two material guide half drum racks 7, and the two material guide half drum racks 7 are located Fig. 9 The feed port 41 shown is used to receive the material from the feed port 41, and the inner wall of the screen body in the material guiding half-cylinder frame 7 is axially provided with reinforcing ribs, which can improve the overall strength and also play a role in guiding flow; the spiral auger extends into the material guiding half-cylinder frame, and the reinforcing ribs are located between the spiral blades of the spiral auger and the screen body.

[0081] The drum frame body is connected to the machine shell 4 by bolts near the discharge end. The drum frame body includes two symmetrically arranged half-drum frames 32, and a pressure plate 33 is bolted between the two half-drum frames 32. The pressure plate 33 extends to the edge of the screen body 11 to press it; the two half-drum frames 32 are fixed by passing a bolt column 324, and a gasket is provided at the bolt column 324, and the bolt column 324 will pass through the pressure plate 33. The half-drum frame 32 includes two strip plates and a plurality of semi-ring frame ribs 321 spaced apart and connected between the two strip plates. An eight-shaped reinforcing rib 322 is welded axially in the middle of the semi-ring frame rib 321, and an axial tension rib 323 is also provided on the semi-ring frame rib 321. The axial tension rib 323 is located on both sides of the eight-shaped reinforcing rib 322. The segmented installation drum frame of the present technology is used to install the screen body, which can realize split disassembly and assembly, and is more efficient. The installation drum frame is divided into two parts, which can not only fix each section of the screen body well, but also disperse the force.

[0082] This embodiment also discloses a method for forming and installing a screw extruder screen. The inventor uses the above-mentioned shaping tooling to achieve the docking installation of two semi-arc screen bodies 11. The specific steps are as follows:

[0083] I. Forming: The outer diameter of the mesh of the final screen body 11 is larger than the inner diameter by means of the rolling and shaping process. For detailed steps, see the rolling and shaping method in step 1 and step 2 of the aforementioned screen shaping process.

[0084] II. Shaping and assembling the installation drum rack: Place the screen body 11 into the installation drum rack 3 and shape it using the adjustment rod; during subsequent installation, fine-tune it using the adjustment rod, and then spot weld the screen body 11 to the installation drum rack 3 in the circumferential direction;

[0085] III. Installation: The limiting ear groove 64 on the back of the installation drum frame 3 is positioned and matched with the protrusion on the screw extruder to facilitate accurate positioning and docking installation with the other half of the screen body 11; during installation, the spacing between adjacent mesh areas 12 is aligned with the Fig. 9 The mesh area 12 corresponds to the hollow area of ​​the installation drum frame 3; after being placed for more than 3 days, the adjustment rod is removed. The adjustment rod shaping tooling in this technology can not only realize the shaping of the screen, but also be used for subsequent installation and adjustment, which reduces the molding process and ensures the installation accuracy.

[0086] As shown in Table 1, the present technology also discloses other embodiments and comparative examples, which are the same as Embodiment 1 except for the following parameters.

[0087] Table 1

[0088]

[0089]

[0090] Experimental Example 1: Rolling Forming

[0091] According to the parameters shown in Example 1 to Comparative Example 4, the aperture of the first punching, the distance d between the centers of radially adjacent mesh holes, the distance f between the centers of axially adjacent mesh holes, the spacing a between adjacent mesh areas 12, the thickness of the plate, etc. The inventor uses the forming process of the screen to bend and curl the plate after the mesh is processed.

[0092] Comparison of Comparative Example 4 with Example 1 shows that when the distance d between the centers of radially adjacent mesh holes is less than 3.5, the mesh holes are greatly deformed when the screen is rolled into a round shape and cannot meet the requirements.

[0093] Experimental Example 2: The screens formed by Examples 1-4, Comparative Examples 1-3, 5-7 were installed in a screw extruder, and after one month of use, they were taken out and visually observed to see if there was obvious deformation and cracking in the appearance; for screens without obvious deformation and cracking, the thickness of the screens was measured by measuring tools (vernier caliper and micrometer), and compared with the thickness before the screens were placed, the thickness deviation of ±0.3mm was considered normal, otherwise it was considered unqualified. Under the same test environment and extrusion pressure, the solid content in the liquid phase of the material extruded using the screen was tested, and the following conclusions were drawn.

[0094]

[0095] Through the above experiments, it can be seen that the use of segmented meshes in embodiments 1-4, with the meshes divided into regions and the aperture of the meshes controlled to be small inside and large outside, has a breakthrough improvement in service life compared with the prior art. Fig.12 and Fig.13 As shown, the integrated screen in comparative example 7 was installed in a screw extruder and used for one month; the screen formed by Example 1 was installed in a screw extruder, and 2 sections were set in the high-pressure area of ​​the screw extruder and 2 sections were set in the low-pressure area; it was used for one month. By comparison, it was found that the segmented screen drum 2 in Example 1, the mesh was divided into regions and the outer aperture of the screen aperture was controlled to be 2.4-2.6 mm, and the inner aperture was 1.9-2.2 mm. The service life of the screen was significantly improved compared with the prior art, and the solid content in the liquid phase was less than 10%.

[0096] In Example 4, the number of screen drum sections is set to three, which means that two sections are set in the high-pressure area and one section is set in the low-pressure area. The performance of the screen is basically the same as that of Example 1, but when replacing the screen, the screen in the low-pressure area needs to be replaced completely, which increases the replacement cost; and compared with Example 1, during molding, since the length of the screen is twice that of the segmented type, the curling is difficult to control, which increases the processing time cost and uncontrollability.

[0097] Comparison between Example 1 and Embodiment 1 shows that the mesh aperture is too small, which has a significant impact on the water filtering efficiency. It is observed that within the same period of time, the amount of filtered water discharged from the liquid outlet 43 in Example 1 is relatively low.

[0098] Comparison of Comparative Example 2 with Example 1 shows that the mesh aperture is set too large, resulting in a solid content in the liquid phase greater than 10%, affecting subsequent processing procedures.

[0099] Comparing Comparative Example 3 with Example 1, it can be seen that if the thickness of the plate is too small, the service life of the screen will be affected. The inventor found that the plate gradually deformed during use and eventually part of it broke. At the same time, the inventor also used plates thicker than 7 mm for rolling and found that the size of the whole machine needed to be increased to match, which was costly.

[0100] Comparing Comparative Example 5 with Example 1, it can be seen that when the distance d between the centers of radially adjacent mesh holes is greater than 4.5 mm, the distance between adjacent mesh holes is too wide, which affects the water filtration efficiency.

[0101] By comparing Comparative Example 6 with Example 1, it can be seen that when the segmented screen drum 2 has two segments, one segment is located in the low-pressure area of ​​the extrusion zone corresponding to the back pressure of the screw extruder of 0 to 10 kg, and the other segment spans the high-pressure area of ​​the extrusion zone corresponding to the back pressure of the screw extruder of 30 to 50 kg. The experiment found that the mesh surface in the high-pressure area was deformed.

[0102] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A screen forming process, characterized in that: The steps include: Step 1: Processing a plurality of meshes on the plate; the plurality of meshes are gathered together to form a mesh area, and a spacing is provided between adjacent mesh areas; Step 2: bend and roll the plate after the mesh is processed in step 1 to form an arc structure with a semicircular cross section and shape it into a screen body; the mesh of the screen body is formed into a structure with a small inner aperture and a large outer aperture through the rolling and shaping process; In step 2, the rolled screen body is shaped by using a mounting drum frame, and a shaping tool is installed on the screen body; the shaping tool includes an adjusting rod, and the adjusting rod includes a left end rod, a right end rod and a connecting rod threadedly connected between the left end rod and the right end rod; The shaping method is as follows: when using a shaping tool to shape the rolled plate, the plate is placed in a close fit in the installation drum frame; at least two adjustment rods are welded in the screen body at intervals, and the length of the adjustment rod is adjusted by twisting the screw on the adjustment rod so that the two ends of the adjustment rod can press the screen body tightly against the inner wall of the installation drum frame.

2. A screen forming process according to claim 1, characterized in that: In step 1, mesh holes are processed on a wear-resistant steel plate having a thickness of 5 to 6 mm by laser drilling.

3. A screen forming process according to any one of claims 1 to 2, characterized in that: In step 1, the mesh aperture R processed on the plate is 2 to 2.5 mm.

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