A dynamic constant pressure precision feeding device for PP strapping production

Abstract

The present invention discloses a dynamic constant pressure precision feeding device for PP strapping production, which relates to the conveying of molding materials, including a machine body and an extrusion assembly arranged on the upper part of the machine body, the extrusion assembly including an extrusion barrel arranged above the machine body for realizing feeding, the interior of the extrusion barrel is rotatably connected to a screw, the interior of the screw is provided with a scraping assembly for removing scale generated during circulating cooling; the scraping assembly includes a bidirectional screw arranged at the inner center of the screw, both ends of the bidirectional screw are rotatably connected to positioning frames, and the outer side of the positioning frame is fixedly connected to the inner wall of the screw, a scraping ring is provided on the outside of the bidirectional screw, and the outer circumferential surface of the scraping ring is fixedly connected to a scraper, one end of the inner part of the bidirectional screw is fixedly connected to a turbine blade, a limiting rod is fixedly connected between the positioning frames, and the limiting rod movably penetrates the scraping ring; by removing scale generated on the inner wall of the screw due to cooling water, the heat conduction efficiency during cooling is guaranteed, the cooling of the screw is stable, and the uniformity of feeding is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of molding material conveying, and in particular to a dynamic constant pressure precision feeding device for producing PP strapping tapes. Background Art

[0002] The automatic precision feeding system for PP strapping tape production refers to the stage in which the raw materials for strapping tape production are introduced into the extruder and melted and extruded by the extruder. The most important link in the PP strapping tape production process is feeding, because uneven feeding will lead to large errors in important parameters such as width, toughness and gram weight of the final product, resulting in a significant decrease in the yield rate.

[0003] The discharge of the extruder is affected by the screw speed, feed amount, material properties, temperature, filter blockage, etc. The screw speed and feed amount can be controlled by adjusting the motor speed, and the material properties can be adjusted accordingly. When the filter is blocked, it can be replaced by an automatic screen changer, and the temperature can be controlled by the cooling system.

[0004] Generally, the heating cylinder is often cooled by air cooling cycle, while the screw is usually cooled by water cooling cycle. When using water cooling cycle, the cooling water is prone to scaling, which leads to an increase in the thickness of the inner wall of the screw, affecting the heat transfer efficiency and the cooling of the screw. If the screw temperature is too high, the melt will not flow smoothly, affecting the feeding efficiency and quality. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem that scaling of the traditional screw during the cooling process leads to reduced heat transfer efficiency, thereby affecting the cooling effect and further affecting the forward movement of material conveying, and to propose a dynamic constant pressure precision feeding device for PP strapping production.

[0006] To achieve the above-mentioned object, the present invention adopts the following technical solution: a dynamic constant pressure precision feeding device for PP strapping production, comprising a body, and an extrusion assembly arranged on the upper part of the body, the extrusion assembly comprising an extrusion barrel arranged above the body for feeding, a screw rotatably connected to the interior of the extrusion barrel, and a scraping assembly provided inside the screw for removing scale generated during circulating cooling;

[0007] The scraping assembly includes a bidirectional screw rod arranged at the inner center of the screw rod, the two ends of the bidirectional screw rod are rotatably connected to the positioning frame, and the outer side of the positioning frame is fixedly connected to the inner wall of the screw rod, the outside of the bidirectional screw rod is provided with a scraper ring, and the outer circular surface of the scraper ring is fixedly connected to the scraper, one end of the inside of the bidirectional screw rod is fixedly connected to the turbine blade, and a limiting rod is fixedly connected between the positioning frames, and the limiting rod movably passes through the scraper ring.

[0008] As a further description of the above technical solution:

[0009] The bidirectional screw rod is in the shape of a column with two ends open and an interior hollow, and a gap is left between one end of the bidirectional screw rod away from the turbine blade and the inner wall of the screw rod.

[0010] As a further description of the above technical solution:

[0011] Both sides of the scraper ring are provided with grinding components, and the grinding components include movable grooves opened on both sides of the scraper ring, and the interior of the movable groove is rotatably connected with a grinding ring.

[0012] As a further description of the above technical solution:

[0013] The sides of the frosted rings that are away from each other extend to the outside of the movable groove, and the inner surface of the frosted ring located outside the movable groove and the outer wall of the limiting rod are both provided with spiral patterns, and the limiting rod and the frosted ring are connected through the spiral patterns.

[0014] As a further description of the above technical solution:

[0015] A scale inhibition component is provided between the scraper ring and the bidirectional screw rod. The scale inhibition component includes a permanent magnet ring movably sleeved on the outside of the bidirectional screw rod. A connecting column is fixedly connected between the permanent magnet ring and the scraper ring. The scraper ring is made of a permanent magnet.

[0016] As a further description of the above technical solution:

[0017] The inner circular surface of the permanent magnet ring is provided with a sliding block which slides inside the sliding groove on the surface of the bidirectional screw rod.

[0018] As a further description of the above technical solution:

[0019] The number of the limiting rods is four, and the four limiting rods are distributed in a circular array on the circular track of the inner circular surface of the frosted ring.

[0020] As a further description of the above technical solution:

[0021] The extrusion assembly also includes a driving unit arranged at the upper end of the body for driving the screw to rotate, a heating cylinder is movably connected to the outside of the extrusion barrel, the upper end of the extrusion barrel is fixedly connected to a feed hopper, one end of the extrusion barrel away from the driving unit is movably connected to a screen changer, and the other end of the screen changer is movably connected to a die head, and an inspection window is provided at the front end of the body.

[0022] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0023] The turbine blades are driven to rotate by impact of cooling water, so the rotation of the turbine blades drives the bidirectional screw to rotate synchronously, and the rotation of the bidirectional screw can drive the scraper ring on its surface to move back and forth left and right. During displacement, the restriction of the limiting rod can prevent the scraper ring from rotating, so that it can only move left and right. During the displacement process, the scraper on the surface of the scraper ring can scrape off the scale attached to the inner wall of the screw, and the scraped scale is discharged with the cooling water, thereby reducing the chance of a decrease in heat conduction efficiency during the water cooling process due to scale coverage, ensuring the stability of the screw cooling, making it stable for material transportation, and ensuring the uniformity of the feed during material extrusion. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Shows an overall schematic diagram provided according to an embodiment of the present invention;

[0025] Figure 2 It shows a view of the combination of an extrusion cylinder and a heating cylinder provided in an embodiment of the present invention;

[0026] Figure 3 A schematic diagram of the internal structure of an extrusion barrel according to an embodiment of the present invention is shown;

[0027] Figure 4 A schematic diagram of the internal structure of a screw provided in an embodiment of the present invention is shown;

[0028] Figure 5 The embodiment of the present invention provides Figure 4 Enlarged view of point A in the middle;

[0029] Figure 6 A schematic diagram of the internal structure of a bidirectional screw rod provided in an embodiment of the present invention is shown;

[0030] Figure 7 A schematic diagram of the combination of a scale grinding component and a scale suppression component provided according to an embodiment of the present invention is shown.

[0031] Legend:

[0032] 10. Body;

[0033] 20. Extrusion assembly; 21. Drive unit; 22. Extrusion barrel; 23. Heating barrel; 24. Feed hopper; 25. Screen changer; 26. Die head; 27. Inspection window; 28. Screw;

[0034] 30. Scraping assembly; 31. Bidirectional screw; 32. Positioning frame; 33. Scraping ring; 34. Limiting rod; 35. Turbine blade; 36. Scraper;

[0035] 40. Grinding assembly; 41. Movable groove; 42. Grinding ring; 43. Spiral pattern;

[0036] 50. Scale suppression assembly; 51. Permanent magnetic ring; 52. Connecting column. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0038] like Figure 1-Figure 7 As shown, the present invention provides a dynamic constant pressure precision feeding device for PP strapping production:

[0039] The machine body 10 includes a body 10 and an extrusion assembly 20 arranged on the upper part of the body 10. The extrusion assembly 20 includes an extrusion barrel 22 arranged above the body 10 for feeding. The internal rotation of the extrusion barrel 22 is connected to a screw 28. The extrusion assembly 20 also includes a drive unit 21 arranged at the upper end of the body 10 for driving the screw 28 to rotate. The external movably sleeve of the extrusion barrel 22 is provided with a heating barrel 23. The upper end of the extrusion barrel 22 is fixedly connected to a feed hopper 24. The end of the extrusion barrel 22 away from the driving unit 21 is movably connected to a screen changer 25, and the other end of the screen changer 25 is movably connected to a die head 26. An inspection window 27 is provided at the front end of the body 10.

[0040] A scraping assembly 30 for removing scale generated during circulating cooling is provided inside the screw 28; the scraping assembly 30 includes a bidirectional screw 31 provided at the inner center of the screw 28, and both ends of the bidirectional screw 31 are rotatably connected to a positioning frame 32, and the outer side of the positioning frame 32 is fixedly connected to the inner wall of the screw 28, a scraping ring 33 is provided on the outside of the bidirectional screw 31, and a scraper 36 is fixedly connected to the outer circular surface of the scraping ring 33, one end of the inside of the bidirectional screw 31 is fixedly connected to a turbine blade 35, a limiting rod 34 is fixedly connected between the positioning frames 32, and the limiting rod 34 movably passes through the scraping ring 33; the bidirectional screw 31 is a cylindrical body with openings at both ends and a hollow interior, and a gap is left between the end of the bidirectional screw 31 away from the turbine blade 35 and the inner wall of the screw 28.

[0041] Specifically, the raw material polypropylene resin particles for producing PP strapping tape are first transported to the inside of the feed hopper 24 through the feeding pump. Then, the material enters the extruder barrel 22 through the feed hopper 24, and the screw 28 is controlled to rotate by the driving unit 21 to realize the transportation of the material. During the transportation process, the material is heated and melted by the heating barrel 23. The molten material is continued to be transported by the screw 28 and first filtered through the screen inside the screen changer 25. Then, it is discharged after being shaped by the die head 26, realizing the feeding operation for the next level of production of PP strapping tape.

[0042] It should be noted that the structure of the driving unit 21 and how the driving unit 21 drives the screw 28 to rotate are both prior arts and common knowledge in the art, so their structure and principles will not be described in detail here.

[0043] During the extrusion process, the screw 28 continuously rubs against the material, thereby increasing the temperature of the screw 28. The increased temperature of the screw 28 will cause the plasticization temperature of the material to be too high and decompose, and will also affect the forward conveyance of the material, resulting in unstable discharge. Therefore, the screw 28 needs to be circulated and cooled. The water cooling system of the screw 28 is common knowledge in the art, so how to introduce cooling water into the interior of the screw 28 will not be described in detail here.

[0044] During cooling, the cooling water enters the inside of the bidirectional screw 31 inside the screw 28, and then the cooling water enters the inside of the screw 28 from the other end of the bidirectional screw 31, and refluxes from the inside of the screw 28 to form a circulating cooling. During the circulating cooling process, since the turbine blades 35 are fixedly connected to the inside of the bidirectional screw 31, the cooling water impacts the turbine blades 35 to drive them to rotate. Since the two ends of the bidirectional screw 31 are movably connected to the inside of the positioning frame 32, the turbine blades 35 rotate and drive the bidirectional screw 31 to rotate synchronously. When the bidirectional screw 31 rotates, it can drive the scraper ring 33 on its surface to move back and forth left and right. When the displacement is made, the limiting rod 34 is used. The restriction prevents the scraper ring 33 from rotating, so that it can only move left and right. During the displacement process, the scraper 36 on the surface of the scraper ring 33 can scrape off the scale attached to the inner wall of the screw 28, and the scraped scale is discharged with the cooling water, thereby reducing the probability of a decrease in heat conduction efficiency during the water cooling process caused by scale coverage, ensuring the stability of the cooling of the screw 28, making it stable for material transportation and ensuring the uniformity of feeding when the material is extruded. At the same time, during the cooling process, the scraper ring 33 always continuously drives the scraper 36 to scrape the inner wall of the screw 28, which not only removes the scale but also reduces the formation and accumulation of scale, making it more convenient and easy to clean the scale.

[0045] It should be noted that in order to prevent the cooling water from heating up too high, the cooling water needs to circulate quickly inside the screw 28. Therefore, a booster pump needs to be used to increase the pressure when injecting the cooling water to ensure that the cooling water has a sufficiently strong water pressure when entering the bidirectional screw 31. Under the action of such high water pressure, the turbine blades 35 will inevitably be driven to rotate and the bidirectional screw 31 will be driven to rotate synchronously.

[0046] like Figure 5 and Figure 7As shown, both sides of the scraper ring 33 are provided with a grinding assembly 40, and the grinding assembly 40 includes a movable groove 41 opened on both sides of the scraper ring 33, and the inner part of the movable groove 41 is rotatably connected to the frosting ring 42; the side of the frosting ring 42 away from the movable groove 41 extends to the outside of the movable groove 41, and the inner circular surface of the frosting ring 42 is located in the area outside the movable groove 41 and the outer wall of the limiting rod 34 are provided with spiral patterns 43, and the limiting rod 34 is spirally connected to the frosting ring 42 through the spiral patterns 43. There are four limiting rods 34, and the four limiting rods 34 are distributed in a circular array on the circular track of the inner circular surface of the frosting ring 42.

[0047] Specifically, since scale will stubbornly adhere to the inner wall of the screw 28 after long-term accumulation, if it is directly scraped off by the scraper 36, it is easy to cause wear to the scraper 36 and the interior of the screw 28, thereby affecting the effect of subsequent scale scraping;

[0048] Based on this, a grinding assembly 40 is set on both sides of the scraper 36. When the scraper ring 33 moves left and right, the grinding ring 42 first grinds the scale through sliding friction, and then uses the scraper 36 to scrape off the ground scale. On the one hand, the ground scale is easier to scrape off, and on the other hand, it reduces the wear on the scraper 36 and the inner wall of the screw 28 when scraping the scale, ensuring the effect of subsequent scale scraping and further improving the scale removal effect. In addition, since the grinding ring 42 is connected by a spiral transmission through the spiral pattern 43, and the four limiting rods 34 are distributed in a circular array on the circular track of the inner circle of the grinding ring 42, a spiral transmission combination of bolts and nuts is formed between the grinding ring 42 and the limiting rods 34. Therefore, when the grinding ring 42 moves left and right, it will be driven to rotate by the spiral pattern 43. Compared with translational grinding, the grinding ring 42 can have a better grinding effect on scale by rotating while displacing, which further improves the scale removal effect and ensures the stable and uniform feeding.

[0049] like Figure 5 and Figure 7 As shown, a scale inhibition component 50 is provided between the scraper ring 33 and the bidirectional screw rod 31. The scale inhibition component 50 includes a permanent magnet ring 51 movably sleeved on the outside of the bidirectional screw rod 31. A connecting column 52 is fixedly connected between the permanent magnet ring 51 and the scraper ring 33. The scraper ring 33 is made of a permanent magnet. The inner circular surface of the permanent magnet ring 51 is provided with a slider that slides inside the slide groove on the surface of the bidirectional screw rod 31.

[0050] Specifically, after the cooling water enters the inside of the bidirectional screw 31, the cooling water will pass through the permanent magnet ring 51. At this time, the magnetic field generated by the permanent magnet ring 51 can change the structure of the particles in the water, making it less likely to adhere to the wall surface, thereby reducing the formation of scale layers. After that, the cooling water flows out from the other end of the bidirectional screw 31, and when it flows back from the inside of the screw 28, it passes through the scraper ring 33 again. The scraper ring 33 is also made of permanent magnets. Therefore, the magnetic field formed by the scraper ring 33 is used to change the structure of the particles in the water again, further reducing the probability of scale layer formation. In addition, the left and right reciprocating motion of the scraper ring 33 can also increase the coverage of the magnetic field on the cooling water, further inhibiting the formation of scale. By solving the influence of scale on the cooling of the screw 28 from the source, the stability and uniformity of the feed are once again guaranteed.

[0051] Instructions for use: First, the raw material polypropylene resin particles for producing PP strapping tape are conveyed to the inside of the feed hopper 24 through the feeding pump, and then the material enters the extrusion barrel 22 through the feed hopper 24, and the screw 28 is controlled to rotate by the driving unit 21 to realize the conveying of the material. During the conveying process, the material is heated and melted by the heating barrel 23. During the extrusion process of the material, the screw 28 continuously rubs against the material, thereby increasing the temperature of the screw 28. At this time, cooling water is passed into the inside of the bidirectional screw 31 inside the screw 28, and then the cooling water enters the inside of the screw 28 from the other end of the bidirectional screw 31, and refluxes from the inside of the screw 28 to form a circulating cooling. During the circulating cooling process, since the turbine blades 35 are fixedly connected to the inside of the bidirectional screw 31, the cooling water impacts the turbine blades 35 to drive it to rotate. When the turbine blades 35 rotate, the bidirectional screw 31 is driven to rotate synchronously. When the screw 31 rotates, it can drive the scraper ring 33 on its surface to move back and forth left and right. During the displacement process, the scraper 36 on the surface of the scraper ring 33 can scrape off the scale attached to the inner wall of the screw 28, and the scraped scale is discharged with the cooling water. At the same time, during the cooling process, the scraper ring 33 always continuously drives the scraper 36 to scrape the inner wall of the screw 28. While removing the scale, it also reduces the formation and accumulation of scale, making it more convenient and easy to clean the scale. Finally, the molten material is continued to be conveyed by the screw 28, first filtered by the screen inside the screen changer 25, and then discharged after being shaped by the die head 26, realizing the feeding operation for the next level of production of PP strapping tape. By removing the scale, the probability of reduced heat conduction efficiency in the water cooling process caused by scale coverage is reduced, thereby ensuring the stability of the cooling of the screw 28, making it stable for material transportation, and ensuring the stability and uniformity of the feed during material extrusion.

[0052] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A dynamic constant pressure precision feeding device for PP strapping production, comprising a body (10), characterized in that: The machine body (10) further comprises an extrusion assembly (20) disposed on the upper portion of the machine body (10), the extrusion assembly (20) comprising an extrusion barrel (22) disposed above the machine body (10) for feeding, a screw (28) being rotatably connected to the interior of the extrusion barrel (22), and a scraping assembly (30) being disposed inside the screw (28) for removing scale generated during circulating cooling; The scraping assembly (30) includes a bidirectional screw rod (31) provided at the inner center of the screw rod (28), two ends of the bidirectional screw rod (31) are rotatably connected to positioning frames (32), and the outer side of the positioning frame (32) is fixedly connected to the inner wall of the screw rod (28), a scraping ring (33) is provided on the outside of the bidirectional screw rod (31), and a scraper (36) is fixedly connected to the outer circumference of the scraping ring (33), one end of the inside of the bidirectional screw rod (31) is fixedly connected to a turbine blade (35), and a limiting rod (34) is fixedly connected between the positioning frames (32), and the limiting rod (34) movably passes through the scraping ring (33); Both sides of the scraper ring (33) are provided with a grinding assembly (40), and the grinding assembly (40) includes a movable groove (41) opened on both sides of the scraper ring (33), and the interior of the movable groove (41) is rotatably connected to a frosting ring (42); the side of the frosting ring (42) away from the movable groove (41) extends to the outside of the movable groove (41), and the inner circular surface of the frosting ring (42) is located in the area outside the movable groove (41) and the outer wall of the limiting rod (34) are provided with a spiral pattern (43), and the limiting rod (34) and the frosting ring (42) are spirally connected through the spiral pattern (43).

2. A dynamic constant pressure precision feeding device for PP strapping production according to claim 1, characterized in that: The bidirectional screw rod (31) is in the shape of a column with both ends open and the interior hollow, and a gap is left between the end of the bidirectional screw rod (31) away from the turbine blade (35) and the inner wall of the screw rod (28).

3. A dynamic constant pressure precision feeding device for PP strapping production according to claim 1, characterized in that: A scale suppression component (50) is provided between the scraper ring (33) and the bidirectional screw rod (31). The scale suppression component (50) comprises a permanent magnet ring (51) movably sleeved on the outside of the bidirectional screw rod (31). A connecting column (52) is fixedly connected between the permanent magnet ring (51) and the scraper ring (33). The scraper ring (33) is made of a permanent magnet.

4. A dynamic constant pressure precision feeding device for PP strapping production according to claim 3, characterized in that: The inner circular surface of the permanent magnet ring (51) is provided with a sliding block that slides inside the sliding groove on the surface of the bidirectional screw rod (31).

5. A dynamic constant pressure precision feeding device for PP strapping production according to claim 3, characterized in that: The number of the limiting rods (34) is four, and the four limiting rods (34) are distributed in a circular array on the circular track of the inner circular surface of the frosted ring (42).

6. A dynamic constant pressure precision feeding device for PP strapping production according to claim 3, characterized in that: The extrusion assembly (20) further comprises a driving unit (21) disposed at the upper end of the machine body (10) for driving the screw (28) to rotate, a heating cylinder (23) being movably sleeved on the outside of the extrusion barrel (22), a feed hopper (24) being fixedly connected to the upper end of the extrusion barrel (22), a screen changer (25) being movably connected to one end of the extrusion barrel (22) away from the driving unit (21), and a die head (26) being movably connected to the other end of the screen changer (25), and an inspection window (27) being provided at the front end of the machine body (10).

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