Multi-scraper rotary melt filter

Abstract

The present invention relates to the field of melt filtration. Disclosed is a multi-scraper rotary melt filter. The multi-scraper rotary melt filter comprises a filter housing member; a rotary extrusion mechanism is provided inside the filter housing member; the filter housing member comprises a middle housing and a discharge port provided on the outer wall of the middle housing; and a feed port is formed in one end of the middle housing, and a waste discharge screw is arranged at the other end of the middle housing. The multi-scraper rotary melt filter is mounted at the tail end of an extruder, a rotating roller rotates, such that a plurality of arc-shaped blades are attached to the inner wall of a filter screen to rotationally scrape waste materials, and the waste is filtered by the filter screen; the plurality of arc-shaped blades are annularly arranged in multiple rows, such that the waste immediately enters the following group of arc-shaped blades once leaving the preceding group of arc-shaped blades, thereby continuously scraping the waste, ensuring that the waste can quickly and effectively enter a conical waste storage cavity, preventing the waste from blocking the filter screen, and improving the filtering efficiency and material recovery rate.

Description

Multi-blade rotary melt filter Technical Field

[0001] This invention relates to the field of melt filtration technology, specifically to a multi-blade rotary melt filter. Background Technology

[0002] A melt filter is used in the processing of molten materials to continuously filter large particles or other impurities in the melt, thereby obtaining a fine and pure molten material, which makes the quality of the product made after the melt solidifies more reliable.

[0003] However, existing melt filters are usually installed at the discharge end of the extruder. The natural pressure of the extruder causes the melt to move inside the filter. During this movement, fine particles in the melt pass through the filter screen and are discharged from the discharge port, while waste is blocked by the filter screen and moves forward into the slag discharge area. In this process, large particles of impurities in the melt adhere to the filter screen, affecting the filtration effect and speed. At the same time, when impurities clog the filter screen, the melt may not have enough time to complete filtration before entering the waste area, resulting in waste of melt material. To address these issues, a multi-blade rotary melt filter is provided. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a multi-blade rotary melt filter, which solves the problem that large particles of impurities in the melt adhere to the filter screen, affecting the filtration effect and speed. Additionally, when impurities clog the filter screen, the melt may enter the waste area before it can be filtered, resulting in waste of melt material.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: a multi-blade scraper rotary melt filter, including a filter housing component, wherein a rotary extrusion mechanism is provided inside the filter housing component, the filter housing component includes a middle section housing and a discharge port opened on the outer wall of the middle section housing, a feed port is provided at one end of the middle section housing, and a waste discharge screw is provided at the other end of the middle section housing;

[0006] The rotary extrusion mechanism includes a rotary filter pressurizing component and a support mesh cylinder disposed outside the rotary filter pressurizing component. The support mesh cylinder is fixedly disposed with the middle section shell, and a discharge chamber communicating with the discharge port is provided between the two.

[0007] The inner wall of the support cylinder is provided with a filter screen, and an extrusion chamber connected to the feed inlet is provided between the filter screen and the rotary filter pressurizing component.

[0008] The waste discharge screw is coaxially fixed with the rotary filter pressurizing component, and the waste discharge screw is located at the end of the extrusion chamber for the discharge of large particles of waste.

[0009] The outer surface of the rotary filter pressurizing component is provided with multiple arc-shaped blades. Multiple sets of arc-shaped blades are attached to the inner wall of the filter screen and rotate around the axis of the rotary filter pressurizing component to scrape off waste. The arc-shaped blades are inclined to one side along the axial direction of the rotary filter pressurizing component, and the end of the previous set of arc-shaped blades extends beyond the end of the next set of arc-shaped blades.

[0010] Preferably, an upper die head is fixedly installed at one end of the middle section housing, the feed inlet is opened on the outer surface of the upper die head, a lower die head is fixedly installed at the other end of the middle section housing, the lower die head is sleeved on the outside of the waste discharge screw, and cooling mechanisms are installed at both ends of the middle section housing.

[0011] Preferably, the cooling mechanism includes:

[0012] The machine head sealing sleeve is fixed to the outer side of the upper machine head, and one end of the machine head sealing sleeve extends into the interior of the upper machine head;

[0013] The material cooling jacket is located on the outer side of the lower head;

[0014] Both the machine head sealing sleeve and the unloading cooling sleeve are equipped with hollow cooling chambers, and a coolant circulation connector is provided on the outer side of the hollow cooling chamber.

[0015] Preferably, a waste discharge pipe is fixedly installed inside the end of the lower head away from the middle section housing, the waste discharge screw is rotatably connected inside the waste discharge pipe, and the discharge cooling jacket is fixedly installed on the outer surface of the waste discharge pipe.

[0016] Preferably, a support cone is fixedly installed on the outer surface of the inner end of the waste discharge screw, and a conical waste storage cavity is formed between the support cone and the inner wall of the lower head. The conical waste storage cavity is connected to the interior of the waste discharge pipe.

[0017] Preferably, an annular feeding cavity is formed between the die head sealing sleeve and the inner wall of the upper die head, and the two ends of the annular feeding cavity are respectively connected to the feed inlet and the extrusion chamber.

[0018] Preferably, the inside of the machine head sealing sleeve is provided with a rotary drive mechanism, the rotary drive mechanism including;

[0019] The drive shaft is mounted at the end of the rotary filter pressurizing component;

[0020] The bearing cover chamber is fixedly mounted on the outer end face of the machine head sealing sleeve;

[0021] A tapered bearing, which is fixedly installed between the drive shaft and the bearing cover chamber;

[0022] The head seal assembly is fixedly installed on the outer surface of the drive shaft, and the head seal assembly is rotatably sealed with the inner wall of the head seal sleeve.

[0023] The wear-resistant sleeve of the machine head is installed on the outer surface of the connection between the rotary filter pressurizing component and the drive shaft, and the wear-resistant sleeve of the machine head is rotatably set with the inner wall of the machine head sealing sleeve.

[0024] Preferably, the rotary filter pressurizing component includes a rotating roller, the arc-shaped blade is mounted on the outer surface of the rotating roller, the two ends of the rotating roller are respectively integrally formed with a drive connection part and a transmission connection part, and the support cone and the wear-resistant sleeve of the head are respectively fixedly mounted on the two ends of the rotating roller.

[0025] Preferably, the end of the drive shaft is integrally formed with a drive connector, which is movably engaged with the drive connection part, and the end of the waste discharge screw is fixedly integrally formed with a transmission connector, which is movably inserted with the transmission connection part.

[0026] Preferably, the arc-shaped blade has an assembly station on the side facing the rotating roller, a spring is installed inside the assembly station, the other end of the spring is fixedly installed inside the rotating roller, and the arc-shaped blade has a slanted scraping groove on the side away from the rotating roller.

[0027] This invention discloses a multi-blade rotary melt filter, which has the following beneficial effects:

[0028] 1. This multi-blade rotary melt filter uses low pressure to force melt into the feed inlet. A drive shaft then rotates the rollers, causing multiple arc-shaped blades to rotate against the inner wall of the filter screen. Through contact with the material, fine particles pass through the filter screen into the discharge chamber, while coarse particles and impurities that do not pass through are scraped away by the arc-shaped blades. This causes the impurities to quickly move towards one end of the conical waste storage chamber. Because the multiple arc-shaped blades are arranged in multiple rows in a ring, with the end of the previous set of blades higher than the front of the next set, the waste material immediately enters the position of the next set of blades after leaving the previous set. This allows the waste residue to quickly enter the conical waste storage chamber, preventing clogging of the filter screen and improving filtration speed and efficiency, thus increasing filtration efficiency and material recovery rate.

[0029] 2. This multi-blade rotary melt filter has cooling mechanisms at both the upper and lower die heads. Cooling water circulates through the coolant circulation joint to reduce the temperature at the waste discharge pipe and the rotary drive mechanism. This allows the material in the spiral groove of the waste discharge screw to change from a molten state to a solid state, ensuring continuous and effective extrusion. It also prevents the die head sealing assembly from overheating, which could lead to seal failure and leakage. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 is a schematic diagram of the overall outer surface structure of the present invention;

[0032] Figure 2 is a schematic diagram of the overall side structure of the present invention;

[0033] Figure 3 is a cross-sectional view of the overall internal structure of the present invention;

[0034] Figure 4 is a schematic diagram of the outer surface structure of the rotary extrusion mechanism of the present invention;

[0035] Figure 5 is a schematic diagram of the outer surface structure of the roller of the present invention;

[0036] Figure 6 is a cross-sectional view of the internal structure of the roller of the present invention;

[0037] Figure 7 is a schematic diagram of the outer surface structure of the transmission joint of the present invention;

[0038] Figure 8 is a schematic diagram of the outer surface structure of the drive connector of the present invention;

[0039] Figure 9 is a cross-sectional view of the internal structure of the lower head of the present invention;

[0040] Figure 10 is a cross-sectional view of the internal structure of the upper part of the present invention;

[0041] Figure 11 is a schematic diagram of the outer surface structure of the arc-shaped blade of the present invention.

[0042] In the diagram: 1. Filter housing; 11. Middle section housing; 12. Upper head; 13. Feed inlet; 14. Discharge outlet; 15. Annular feed chamber; 16. Discharge chamber; 17. Support cone; 18. Conical waste storage chamber; 19. Waste discharge pipe; 110. Waste discharge screw; 111. Lower head; 112. Transmission joint; 2. Rotary drive mechanism; 21. Drive shaft; 22. Bearing cover chamber; 23. Conical bearing; 24. Head sealing assembly; 25. Drive... 26. Connector; 3. Head wear-resistant sleeve; 4. Cooling mechanism; 5. Head sealing sleeve; 6. Feeding cooling sleeve; 7. Hollow cooling chamber; 8. Coolant circulation connector; 9. Rotary extrusion mechanism; 10. Rotary filter pressurizing component; 11. Rotary roller; 12. Arc-shaped blade; 13. Spring component; 14. Transmission connection part; 15. Drive connection part; 16. Assembly station; 17. Angled scraper groove; 18. Filter screen; 19. Support screen cylinder. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] This application provides a multi-blade rotary melt filter, which solves the problem that large particles of impurities in the melt adhere to the filter screen, affecting the filtration effect and speed. At the same time, when impurities clog the filter screen, the melt may enter the waste area before it can be filtered, resulting in waste of melt material.

[0045] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0046] This invention discloses a multi-blade rotary melt filter.

[0047] As shown in Figures 1-11, the filter housing 1 includes a filter housing component 1, and a rotary extrusion mechanism 4 is provided inside the filter housing component 1. The filter housing component 1 includes a middle section housing 11 and a discharge port 14 opened on the outer wall of the middle section housing 11. A feed port 13 is provided at one end of the middle section housing 11, and a waste discharge screw 110 is provided at the other end of the middle section housing 11.

[0048] The rotary extrusion mechanism 4 includes a rotary filter pressurizing component 41 and a support mesh cylinder 43 disposed outside the rotary filter pressurizing component 41. The support mesh cylinder 43 is fixedly disposed with the middle section shell 11, and a discharge chamber 16 communicating with the discharge port 14 is provided between the two.

[0049] The inner wall of the support cylinder 43 is provided with a filter screen 42, and an extrusion chamber connected to the feed inlet 13 is provided between the filter screen 42 and the rotary filter pressurizing component 41.

[0050] The waste discharge screw 110 is coaxially fixed with the rotary filter pressurizing component 41. The waste discharge screw 110 is located at the end of the extrusion chamber for the discharge of large particles of waste.

[0051] The outer surface of the rotary filter pressurizing component 41 is provided with multiple arc-shaped blades 412. The multiple sets of arc-shaped blades 412 are attached to the inner wall of the filter screen 42 and rotate around the axis of the rotary filter pressurizing component 41 to scrape off waste.

[0052] The arc-shaped blades 412 are tilted to one side along the axis of the rotary filter pressurizing element 41, and the end of the first set of arc-shaped blades 412 extends beyond the end of the second set of arc-shaped blades 412.

[0053] An upper head 12 is fixedly installed at one end of the middle section housing 11, and a feed inlet 13 is opened on the outer surface of the upper head 12. A lower head 111 is fixedly installed at the other end of the middle section housing 11. The lower head 111 is sleeved on the outside of the waste discharge screw 110. Cooling mechanisms 3 are installed at both ends of the middle section housing 11.

[0054] The cooling mechanism 3 includes a head sealing sleeve 31 and a discharge cooling sleeve 32. The head sealing sleeve 31 is fixed to the outer side of the upper head 12, and one end of the head sealing sleeve 31 extends into the interior of the upper head 12. The discharge cooling sleeve 32 is disposed on the outer side of the lower head 111. Both the head sealing sleeve 31 and the discharge cooling sleeve 32 are provided with hollow cooling chambers 33, and coolant circulation connectors 34 are provided on the outer side of the hollow cooling chambers 33. A waste discharge pipe 19 is fixedly installed inside the lower head 111 at the end away from the middle section housing 11. A waste discharge screw 110 is rotatably connected to the interior of the waste discharge pipe 19, and the discharge cooling sleeve 32 is fixedly installed on the outer surface of the waste discharge pipe 19.

[0055] The cooling water is circulated through the feeding cooling jacket 32 ​​to reduce the temperature of the waste discharge pipe 19, thereby reducing the temperature of the material in the spiral groove of the waste discharge screw 110, causing it to change from a molten state to a solid state. The spiral groove of the waste discharge screw 110 is designed with a certain angle to ensure that material is discharged only when the waste discharge screw 110 rotates. In use, when the drive shaft 21 drives the rotating roller 411 to rotate, it synchronously drives the waste discharge screw 110 to rotate, realizing the spiral conveying of waste outward.

[0056] Coolant circulates through the hollow cooling chamber 33 in the head seal sleeve 31 to absorb heat, thereby reducing the temperature of the head seal assembly 24 and ensuring that the plastic melt does not leak out through the gap between the drive shaft 21 and the head seal assembly 24. The head seal assembly 24 adopts a combined packing seal, which in this case is composed of a copper gasket and a non-metallic heat insulation gasket.

[0057] A support cone 17 is fixedly installed on the outer surface of the inner end of the waste discharge screw 110. A conical waste storage cavity 18 is formed between the support cone 17 and the inner wall of the lower head 111. The conical waste storage cavity 18 is connected to the interior of the waste discharge pipe 19.

[0058] An annular feeding cavity 15 is formed between the die head sealing sleeve 31 and the inner wall of the upper die head 12. The two ends of the annular feeding cavity 15 are connected to the feed inlet 13 and the extrusion chamber, respectively.

[0059] The head sealing sleeve 31 is internally equipped with a rotary drive mechanism 2, which includes a drive shaft 21, a bearing cover chamber 22, a tapered bearing 23, a head sealing assembly 24, and a head wear-resistant sleeve 26. The drive shaft 21 is installed at the end of the rotary filter pressurizing component 41; the bearing cover chamber 22 is fixedly installed on the outer end face of the head sealing sleeve 31; the tapered bearing 23 is fixedly installed between the drive shaft 21 and the bearing cover chamber 22; the head sealing assembly 24 is fixedly installed on the outer surface of the drive shaft 21, and the head sealing assembly 24 is rotatably sealed with the inner wall of the head sealing sleeve 31; the head wear-resistant sleeve 26 is installed on the outer surface of the connection between the rotary filter pressurizing component 41 and the drive shaft 21, and the head wear-resistant sleeve 26 is rotatably arranged with the inner wall of the head sealing sleeve 31.

[0060] The tapered bearing 23 is provided to counteract the axial thrust of the plastic melt on the drive shaft 21. During operation, there is a certain pressure inside the filter, which will force the drive shaft 21 to move backward. This thrust must be counteracted, hence the tapered bearing 23. This structure can also be a thrust bearing or a thrust sliding bearing.

[0061] The rotary filter pressurizing component 41 includes a rotating roller 411, an arc-shaped blade 412 mounted on the outer surface of the rotating roller 411, and a drive connection part 415 and a transmission connection part 414 integrally formed at both ends of the rotating roller 411, respectively. The support cone 17 and the wear-resistant sleeve 26 of the head are respectively fixedly installed at the two ends of the rotating roller 411.

[0062] The end of the drive shaft 21 is integrally formed with a drive connector 25, which is movably engaged with the drive connection part 415. The end of the waste discharge screw 110 is integrally formed with a transmission connector 112, which is movably inserted with the transmission connection part 414.

[0063] An assembly station 416 is provided on the side of the arc-shaped blade 412 facing the rotating roller 411. A spring 413 is installed inside the assembly station 416. The other end of the spring 413 is fixedly installed inside the rotating roller 411. A slanted scraping groove 417 is provided on the side of the arc-shaped blade 412 away from the rotating roller 411. By slanting the scraping groove 417, the contact area between the arc-shaped blade 412 and the filter screen is reduced, thereby effectively scraping away impurities from the inner wall of the filter screen 42.

[0064] Working principle: When in use, the device connects the feed inlet 13 to an extruder. Under the natural pressure of the extruder, the melt enters the filter. Simultaneously, an external drive component installed at the end of the drive shaft 21 causes the drive shaft 21 to rotate. At this time, the external melt enters the extrusion chamber through the annular feed cavity 15, and under pressure, the melt moves along the extrusion chamber towards the conical waste storage cavity 18. At this time, the drive shaft 21 drives the rotating roller 411 to rotate, causing multiple arc-shaped blades 412 to rotate against the inner wall of the filter screen 42. Under the action of the spring component 413, the arc-shaped blades 412 are tightly attached to the inner wall of the filter screen 42. At this time, the arc-shaped blades 412 quickly scrape off the waste residue attached to the inner wall of the filter screen 42, causing the residue to move in a spiral state. In this process, fine material passes through the filter screen 42 and enters the discharge chamber 16, and is finally discharged through the discharge port 14. Coarse material and impurities that do not pass through the filter screen 42 are pushed forward into the conical waste storage chamber 18, and then spirally extruded outward by the waste discharge screw 110. During this process, since multiple arc blades 412 are arranged in multiple rows in a ring, and the end of the previous set of arc blades 412 is higher than the front end of the next set of arc blades 412, the material immediately enters the end position of the next set of arc blades 412 after leaving the previous set of arc blades 412, thereby achieving continuous scraping of waste and avoiding missed scraping of waste. This ensures that most of the material can be filtered and collected when it enters the conical waste storage chamber 18, improving filtration efficiency and material recovery rate.

[0065] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A multi-blade rotary melt filter, comprising a filter housing (1), wherein a rotary extrusion mechanism (4) is provided inside the filter housing (1), characterized in that: The filter housing component (1) includes a middle section housing (11) and a discharge port (14) opened on the outer wall of the middle section housing (11). One end of the middle section housing (11) is provided with a feed inlet (13), and the other end of the middle section housing (11) is provided with a waste discharge screw (110). The rotary extrusion mechanism (4) includes a rotary filter pressurizing component (41) and a support mesh cylinder (43) disposed outside the rotary filter pressurizing component (41). The support mesh cylinder (43) is fixedly disposed with the middle section shell (11), and a discharge chamber (16) connected to the discharge port (14) is provided between the two. The inner wall of the support mesh cylinder (43) is provided with a filter screen (42), and an extrusion chamber connected to the feed inlet (13) is provided between the filter screen (42) and the rotary filter pressurizing component (41). The waste discharge screw (110) is coaxially fixed with the rotary filter pressurizing component (41), and the waste discharge screw (110) is set at the end of the extrusion chamber for the discharge of large particles of waste. The outer surface of the rotary filter pressurizing component (41) is provided with multiple arc-shaped blades (412). The multiple sets of arc-shaped blades (412) are attached to the inner wall of the filter screen (42) and rotate around the axis of the rotary filter pressurizing component (41) to scrape off waste. The arc-shaped blades (412) are tilted to one side along the axis of the rotary filter pressurizing member (41), and the end of the first set of arc-shaped blades (412) extends beyond the end of the second set of arc-shaped blades (412).

2. The multi-blade doctor roll rotary melt filter of claim 1, wherein: One end of the middle section housing (11) is fixedly installed with an upper head (12), the feed port (13) is opened on the outer surface of the upper head (12), the other end of the middle section housing (11) is fixedly provided with a lower head (111), the lower head (111) is sleeved on the outside of the waste discharge screw (110), and cooling mechanisms (3) are installed at both ends of the middle section housing (11).

3. The multi-blade doctor roll rotary melt filter of claim 2, wherein: The cooling mechanism (3) includes: The machine head sealing sleeve (31) is fixed to the outside of the upper machine head (12), and one end of the machine head sealing sleeve (31) extends into the inside of the upper machine head (12); The material cooling jacket (32) is located on the outer side of the lower head (111); Both the machine head sealing sleeve (31) and the unloading cooling sleeve (32) are provided with hollow cooling chambers (33), and a coolant circulation connector (34) is provided on the outside of the hollow cooling chambers (33).

4. The multi-blade doctor roll rotary melt filter of claim 3, wherein: The lower head (111) is fixedly fitted with a waste discharge pipe (19) at one end away from the middle section housing (11). The waste discharge screw (110) is rotatably connected to the inside of the waste discharge pipe (19). The discharge cooling sleeve (32) is fixedly installed on the outer surface of the waste discharge pipe (19).

5. The multi-blade doctor roll rotary melt filter of claim 4, wherein: A support cone (17) is fixedly installed on the outer surface of the inner end of the waste discharge screw (110). A conical waste storage cavity (18) is formed between the support cone (17) and the inner wall of the lower head (111). The conical waste storage cavity (18) is connected to the interior of the waste discharge pipe (19).

6. The multi-blade doctor roll rotary melt filter of claim 3, wherein: The sealing sleeve (31) of the machine head and the inner wall of the upper machine head (12) form an annular feeding cavity (15), and the two ends of the annular feeding cavity (15) are respectively connected to the feed inlet (13) and the extrusion chamber.

7. The multi-blade doctor roll rotary melt filter of claim 5, wherein: The machine head sealing sleeve (31) is provided with a rotary drive mechanism (2), which includes: A drive shaft (21) is mounted at the end of a rotary filter pressurizing element (41); The bearing cover chamber (22) is fixedly installed on the outer end face of the machine head sealing sleeve (31); A tapered bearing (23) is fixedly installed between the drive shaft (21) and the bearing cover chamber (22); The head seal assembly (24) is fixedly installed on the outer surface of the drive shaft (21), and the head seal assembly (24) is rotatably sealed with the inner wall of the head seal sleeve (31). The wear-resistant sleeve (26) of the head is installed on the outer surface of the connection between the rotary filter pressurizing component (41) and the drive shaft (21). The wear-resistant sleeve (26) of the head is rotatably set with the inner wall of the head sealing sleeve (31).

8. The multi-blade doctor roll rotary melt filter of claim 7, wherein: The rotary filter pressurizing component (41) includes a rotating roller (411), the arc-shaped blade (412) is installed on the outer surface of the rotating roller (411), and the two ends of the rotating roller (411) are integrally formed with a drive connection part (415) and a transmission connection part (414), respectively. The support cone (17) and the wear-resistant sleeve (26) of the head are respectively fixedly installed at the two ends of the rotating roller (411).

9. The multi-blade doctor roll rotary melt filter of claim 8, wherein: The drive shaft (21) has an integrally formed drive connector (25) at its end, which is movably engaged with the drive connection part (415). The waste discharge screw (110) has an integrally formed transmission connector (112) at its end, which is movably inserted with the transmission connection part (414).

10. The multi-blade doctor roll rotary melt filter of claim 8, wherein: An assembly station (416) is provided on the side of the arc-shaped blade (412) facing the rotating roller (411). A spring (413) is installed inside the assembly station (416). The other end of the spring (413) is fixedly installed inside the rotating roller (411). A slanted scraping groove (417) is provided on the side of the arc-shaped blade (412) away from the rotating roller (411).

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