A double screen changer for plastic sheet production
The dual-filter design of the dual screen changer system solves the problem of incomplete impurity removal in single-stage filtration systems under high-throughput conditions, improves the flatness of plastic sheets and the stability of the device, and reduces maintenance costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- DONGGUAN DEKAI PLASTIC CO LTD
- Filing Date
- 2025-08-01
- Publication Date
- 2026-07-21
AI Technical Summary
Existing single-stage filtration systems are ineffective at removing micron-sized impurities during the production of plastic sheets under high-throughput conditions, resulting in insufficient surface quality and flatness, especially in applications such as optical films and packaging films.
A dual screen changer system is adopted, including a first screen changer and a second screen changer, which are connected in series horizontally through connecting pipes to achieve dual filtration. The first screen changer and the second screen changer use filter screens with different mesh sizes. Combined with a tapered connecting pipe and flange connection, a hydraulic cylinder drives a sliding plate to achieve stable filtration and sealing, reducing impurity residue and leakage.
It effectively reduces surface defects of plastic sheets, improves flatness, device stability and sealing, and reduces device maintenance costs.
Smart Images
Figure CN224527963U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of plastic equipment technology, and in particular to a dual screen changer for the production of plastic sheets. Background Technology
[0002] Plastic sheets are widely used in packaging, construction, industry and medical fields due to their lightweight, corrosion resistance and easy processing properties. During the production of plastic sheets, impurities in the molten plastic will directly affect the surface quality and mechanical properties of the final product.
[0003] In related technologies, screen changers are a type of filtration equipment used in the plastics processing process. Currently, the industry generally adopts single-stage filtration systems, which use metal filter screens to intercept and remove impurity particles from plasticized materials.
[0004] The existing screen changers have the following problems: As downstream applications continue to increase their requirements for the flatness of plastic sheets, especially in the fields of optical films and packaging films, people’s requirements for impurity control have reached the micron level. In recent years, the increase in extruder capacity has led to an increase in the throughput of plastic melt, and single-stage filtration systems are unable to filter out most of the impurities and foreign particles in one go under high-throughput conditions. Summary of the Invention
[0005] To improve the flatness of plastic sheets, this application provides a double screen changer for plastic sheet production.
[0006] The technical solution provided in this application for a dual screen changer for plastic sheet production is as follows: A dual screen changer for producing plastic sheets includes: a first screen changer, a second screen changer, and a connecting pipe, wherein the connecting pipe is used for feeding, and the first screen changer, the connecting pipe, and the second screen changer are connected in series in the horizontal feeding direction.
[0007] By adopting the above scheme, the plasticized material is horizontally transported through the connecting pipeline and passes through the first screen changer and the second screen changer in sequence to achieve dual filtration. This effectively reduces the occurrence of surface defects in plastic sheets caused by residual impurities in the single-stage filtration system, and indirectly improves the flatness of the plastic sheets produced in subsequent production.
[0008] Preferably, the first screen changer includes a first filter, a first housing, and a first support plate. The first support plate is slidably disposed on the inner side wall of the first housing in a vertical direction, and the first filter is supported on the first support plate.
[0009] By adopting the above scheme, the first bearing plate provides rigid support for the first filter screen. When the plastic material passes through, the first filter screen forms a stable filtration interface, intercepting impurities while dispersing the fluid impact force. The sliding setting ensures that the first bearing plate fits tightly against the side wall of the first housing, reducing the occurrence of material bypass leakage.
[0010] Preferably, the second screen changer includes a second filter, a second housing, and a second support plate. The second support plate is slidably disposed on the inner side wall of the second housing in a vertical direction, and the second filter is supported on the second support plate.
[0011] By adopting the above scheme, the second bearing slide plate plays a rigid support role for the second filter screen. When the plasticized material passes through, the second filter screen forms a stable filtration interface, intercepting impurities while dispersing the fluid impact force. The sliding setting makes the second bearing slide plate fit tightly against the side wall of the second housing, reducing the occurrence of material bypass leakage.
[0012] Preferably, the mesh count of the second filter is greater than that of the first filter.
[0013] By adopting the above scheme, the second screen changer uses a higher mesh size filter screen, which forms a coarse-fine graded filtration with the first filter screen of the first screen changer. The first filter screen is responsible for intercepting larger impurities, while the second filter screen is responsible for further intercepting fine particles, effectively improving the purity of the output material.
[0014] Preferably, the internal piping of the connecting pipe is arranged in a tapering structure.
[0015] By adopting the above scheme, the first filter screen with a smaller mesh size is placed at the beginning of the tapered section of the internal pipeline of the connecting pipe. The larger initial cross-sectional area disperses the fluid impact. The narrowest part of the tapered section is connected to the second filter screen with a larger mesh size. The low-pressure zone formed by the Bernoulli effect reduces the inlet pressure of the second filter screen, thereby reducing the occurrence of damage to the high-mesh filter screen due to excessive pressure difference.
[0016] Preferably, flanges are provided at both ends of the connecting pipe.
[0017] By adopting the above scheme, the first screen changer and the second screen changer are fixedly connected to both ends of the connecting pipe by flange bolts, which improves the stability of the device and the connection strength.
[0018] Preferably, the mounting surface of the flange is provided with a sealing gasket.
[0019] By adopting the above scheme, the pre-tightening force of the flange bolts is used to compress the sealing gasket between the flanges, causing the sealing gasket to deform and fill the micro gaps, reducing the occurrence of plastic material leakage and improving the sealing performance of the device.
[0020] Preferably, the device further includes a screen-changing execution component, which is provided in two sets. Each set of the screen-changing execution component includes a hydraulic cylinder and a guide rail. The guide rails are symmetrically arranged on both sides of the inner wall of the first housing and the second housing. The side walls of the first bearing plate and the second bearing plate are adapted to the guide rails. The hydraulic cylinders are respectively arranged above the first bearing plate and the second bearing plate. The hydraulic rods of the hydraulic cylinders are vertically arranged and respectively connected to the top of the first bearing plate and the second bearing plate.
[0021] By adopting the above scheme, the hydraulic cylinder drives the hydraulic rod to move the first or second load-bearing slide plate vertically along the guide rail. The guide rail plays a guiding and limiting role, reducing the horizontal offset when the first or second load-bearing slide plate is raised or lowered. The clogged first or second filter screen can slide down to get out of the work station and be reset after manual replacement of the new filter screen, and then re-enter the work process.
[0022] In summary, this application includes at least one of the following beneficial technical effects: 1. After the plastic material undergoes double filtration, the surface defects of the plastic sheet caused by residual impurities in the single-stage filtration system are effectively reduced, which indirectly improves the flatness of the plastic sheet produced in subsequent production. 2. It reduced the occurrence of material leakage and improved the sealing performance of the equipment; 3. Improved the stability and connection strength of the device. Attached Figure Description
[0023] Fig. 1 This is a schematic diagram of the overall structure of an embodiment of this application.
[0024] Fig. 2 This is a schematic diagram illustrating the cooperative relationship between the first network switcher and the network switching execution component in an embodiment of this application.
[0025] Explanation of reference numerals in the attached drawings: 1. Connecting pipe; 11. Flange; 12. Sealing gasket; 2. First screen changer; 21. First housing; 22. First filter screen; 23. First load-bearing slide plate; 3. Second screen changer; 31. Second housing; 32. Second filter screen; 33. Second load-bearing slide plate; 4. Screen changing actuator; 41. Hydraulic cylinder; 42. Guide rail. Detailed Implementation
[0026] The following is in conjunction with the appendix Figs. 1-2 This application will be described in further detail.
[0027] This application discloses a dual screen changer for plastic sheet production. (Refer to...) Figs. 1-2A dual screen changer for producing plastic sheets includes a first screen changer 2, a second screen changer 3, and a connecting pipe 1. The connecting pipe 1 is used for feeding. The first screen changer 2, the connecting pipe 1, and the second screen changer 3 are connected in series in the horizontal feeding direction.
[0028] Therefore, during the horizontal conveying process, the plastic material undergoes continuous filtration through two stages of screen changer 2 and screen changer 3 connected in series, which effectively reduces the content of impurities remaining due to insufficient filtration in a single stage, reduces surface defects caused by impurities during the molding of plastic sheets, and indirectly improves the flatness of the finished plastic sheet products.
[0029] In the process described above, the first screen changer 2 includes a first filter 22, a first housing 21, and a first support plate 23. The first support plate 23 is slidably disposed on the inner side wall of the first housing 21 in a vertical direction, and the first filter 22 is correspondingly installed on the first support plate 23.
[0030] Therefore, the first bearing plate 23, as the rigid support structure of the first filter screen 22, maintains the shape stability of the first filter screen 22 during the flow of plasticized material, and forms a high-efficiency filtration barrier to intercept and remove impurities. At the same time, it disperses the dynamic pressure of the fluid and buffers the impact effect of material flow.
[0031] Furthermore, the first bearing slide plate 23 forms a dynamic sealing interface by sliding and engaging with the first housing 21, which effectively reduces the occurrence of material bypass leakage and improves the filtration accuracy of the device.
[0032] On the other hand, the second screen changer 3 is provided in relation to the first screen changer 2, and includes a second filter 32, a second housing 31 and a second support plate 33. The second support plate 33 is slidably disposed on the inner side wall of the second housing 31 in the vertical direction, and the second filter 32 is supported on the second support plate 33.
[0033] Correspondingly, in this embodiment, both the first housing 21 and the second housing 31 are arranged in a box-shaped structure, and the bottom of the first housing 21 and the second housing 31 can collect materials and impurities that leak out of the equipment and drip downwards.
[0034] Furthermore, in this embodiment, both the first filter screen 22 and the second filter screen 32 are arranged in a disc-shaped structure, and the cross-sectional size of the first filter screen 22 and the second filter screen 32 is adapted to the cross-sectional size of the connecting pipe 1.
[0035] Furthermore, in this embodiment, both the first bearing plate 23 and the second bearing plate 33 have two hollow circular holes in the vertical direction. The inner wall of the hollow circular hole has a groove adapted to the first filter screen 22 or the second filter screen 32. The first filter screen 22 or the second filter screen 32 is mechanically squeezed into the groove. Therefore, the dual filter screen structure of the single screen changer allows the other filter screen to be used alternately when one filter screen is replaced, thereby achieving maintenance without stopping the machine.
[0036] Correspondingly, after installation, the staff needs to use tools to press the edge of the first filter screen 22 or the second filter screen 32 completely to the bottom of the groove to ensure that there are no protrusions, so as to reduce the occurrence of the first filter screen 22 or the second filter screen 32 falling off and the first bearing plate 23 or the second bearing plate 33 being obstructed from moving.
[0037] Meanwhile, the mesh count of the second filter 32 is greater than that of the first filter 22. In this embodiment, the first filter 22 is a woven filter, and the second filter 32 is a sintered filter.
[0038] Therefore, the second filter 32, by using a filter with a higher mesh size, forms a coarse-fine graded filtration with the first filter 22. The first filter 22, as the first barrier, utilizes the surface interception characteristics of the woven filter to physically block larger impurities and foreign particles through its mesh size, thereby reducing the load on the downstream second filter 32 and lowering the risk of clogging.
[0039] Correspondingly, the second filter screen 32 serves as a secondary filtration unit. It traps fine impurities in the material through the deep filtration mechanism of the sintered filter screen. Its three-dimensional pore structure can accommodate more pollutants and has stronger impact resistance. The combination of the two improves the purity of the outflowing material.
[0040] In addition, the internal pipeline of the connecting pipe 1 is set in a tapered structure. The first filter screen 22 with a smaller mesh size is placed at the beginning of the tapered section of the internal pipeline of the connecting pipe 1. The large initial cross-sectional area disperses the fluid impact, and the low resistance allows the fluid to pass through at high speed, reducing the occurrence of fine particles remaining on the surface of the first filter screen 22 to form a filter cake, thus reducing the risk of clogging.
[0041] Furthermore, in Bernoulli's principle, p + 1 / 2ρv² + ρgh = c, where ρ is density, v is velocity, h is height, p is static pressure, and c is a constant. That is, in flow at the same height, an increase in velocity leads to a decrease in static pressure, and vice versa.
[0042] Therefore, the narrowest part of the tapered section connects to the second filter screen 32 with a larger mesh size. The opening of the second filter screen 32 is small, which increases the fluid resistance and causes the plasticized material to flow through the second filter screen 32 at a low speed. This prolongs the contact time between the material and the second filter screen 32, improves the interception efficiency of fine particles, and reduces the inlet pressure of the second filter screen 32 by utilizing the low-pressure zone formed by the Bernoulli effect. This reduces the occurrence of damage to the high-mesh filter screen due to excessive pressure difference and extends the service life of the second filter screen 32.
[0043] On the other hand, flanges 11 are installed at both ends of the connecting pipe 1, and sealing gaskets 12 are fixed on the mating surfaces of the flanges 11.
[0044] Therefore, the first screen changer 2 and the second screen changer 3 are connected to the flanges 11 at both ends of the connecting pipe 1 by flange bolts 11, and the three are rigidly connected to form a complete conveying system, which improves the stability and connection strength of the device.
[0045] At the same time, the bolts of flange 11 use the bolt preload to compress the sealing gasket 12 between flanges 11, causing the sealing gasket 12 to deform and fill the micro gaps, thereby reducing the occurrence of plastic material leakage and further improving the sealing performance of the device.
[0046] Furthermore, the bolt fastening method facilitates disassembly, maintenance, or replacement of components by operators, effectively reducing the maintenance cost of the equipment.
[0047] In addition, the device also includes a screen changing execution component 4. There are two sets of screen changing execution components 4, which are respectively installed inside the first housing 21 and the second housing 31. Each set of screen changing execution components 4 includes a hydraulic cylinder 41 and a guide rail 42. The guide rail 42 is symmetrically installed on both sides of the inner wall of the first housing 21 and the second housing 31. The hydraulic cylinder 41 is fixed above the first bearing plate 23 and the second bearing plate 33. The hydraulic rod of the hydraulic cylinder 41 is vertically arranged and connected to the top of the first bearing plate 23 and the second bearing plate 33 respectively.
[0048] Correspondingly, the hydraulic cylinder 41 drives the hydraulic rod to move the first bearing plate 23 or the second bearing plate 33 vertically back and forth along the guide rail 42. The guide rail 42 guides and limits the first bearing plate 23 and the second bearing plate 33, and reduces the horizontal displacement of the bearing plate during lifting and lowering by physical blocking.
[0049] Furthermore, the clogged first filter screen 22 or second filter screen 32 can slide down to detach from the work station. After the maintenance personnel manually replace the new filter screen, the hydraulic cylinder 41 drives the hydraulic rod to move the first bearing slide plate 23 or the second bearing slide plate 33 back to the initial work station precisely, and the filtration operation is restored.
[0050] The implementation principle of a dual screen changer for plastic sheet production in this application embodiment is as follows: During the horizontal conveying process, the plasticized material passes through two stages of continuous coarse and fine grade filtration, namely the first filter screen 22 and the second filter screen 32 connected in series. This effectively reduces the impurity content remaining due to insufficient filtration in a single stage, reduces surface defects caused by impurities during the plastic sheet molding process, and indirectly improves the flatness of the subsequent finished plastic sheet.
[0051] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.
Claims
1. A double screen changer for plastic sheet production, characterized in that, It includes a first screen changer (2), a second screen changer (3), and a connecting pipe (1). The connecting pipe (1) is used for feeding. The first screen changer (2), the connecting pipe (1), and the second screen changer (3) are connected in series in the horizontal feeding direction.
2. A double screen changer for plastic sheet production according to claim 1, characterized in that, The first screen changer (2) includes a first filter screen (22), a first housing (21) and a first support plate (23). The first support plate (23) is slidably disposed on the inner side wall of the first housing (21) in the vertical direction, and the first filter screen (22) is supported on the first support plate (23).
3. A double screen changer for plastic sheet production according to claim 2, characterized in that, The second screen changer (3) includes a second filter screen (32), a second housing (31) and a second support plate (33). The second support plate (33) is slidably disposed on the inner side wall of the second housing (31) in the vertical direction, and the second filter screen (32) is supported on the second support plate (33).
4. A double screen changer for plastic sheet production according to claim 3, characterized in that, The mesh count of the second filter (32) is greater than that of the first filter (22).
5. A double screen changer for plastic sheet production according to claim 1, characterized in that, The internal piping of the connecting pipe (1) is arranged in a tapering structure.
6. A double screen changer for plastic sheet production according to claim 1, characterized in that, Flanges (11) are provided at both ends of the connecting pipe (1).
7. A double screen changer for plastic sheet production according to claim 6, characterized in that, The mounting surface of the flange (11) is provided with a sealing gasket (12).
8. A double screen changer for plastic sheet production according to claim 3, characterized in that, It also includes a screen changing execution component (4), which is provided in two sets. Both sets of the screen changing execution component (4) include a hydraulic cylinder (41) and a guide rail (42). The guide rail (42) is symmetrically arranged on both sides of the inner wall of the first housing (21) and the second housing (31). The side walls of the first bearing plate (23) and the second bearing plate (33) are adapted to the guide rail (42). The hydraulic cylinder (41) is respectively arranged above the first bearing plate (23) and the second bearing plate (33). The hydraulic rod of the hydraulic cylinder (41) is arranged vertically and is respectively connected to the top of the first bearing plate (23) and the second bearing plate (33).