A grinding device for preparing a graphene modified polyolefin composite film material

Abstract

This application relates to the field of grinding equipment technology and discloses a grinding device for preparing graphene-modified polyolefin composite film materials. The device includes a drive shaft with multiple sets of stirring units connected end-to-end within it. Each stirring unit includes a rotating drum, and spiral stirring blades are fixedly connected to the outer wall of the drum. The multiple sets of spiral stirring blades can be connected end-to-end to form a propeller. During startup, the starting gear and the maintaining gear move axially and mesh with the driven gears one by one, driving the stirring units to rotate sequentially. This invention provides a grinding device for preparing graphene-modified polyolefin composite film materials. When using this vertical stirring mill, excessively worn stirring units can be replaced individually, reducing replacement costs. Alternatively, the order of the stirring units can be adjusted periodically to extend their service life and reduce operating costs. During startup, the stirring units are driven sequentially, significantly reducing the starting torque.

Description

Technical Field

[0001] This application relates to the field of grinding equipment technology, and in particular to a grinding device for preparing graphene-modified polyolefin composite film materials. Background Technology

[0002] Inorganic particle-modified polymers possess the advantages of polymers such as processability, dielectric properties, and toughness, while also combining the advantages of inorganic materials such as rigidity, thermal stability, and flame retardancy. The two properties complement each other, resulting in a wide range of applications. They can be used as materials for producing electronic packaging films and functional food packaging films.

[0003] Nano-reinforced polyolefin composites are generally based on the ability to improve the properties of polyolefins with a relatively small amount of nanofillers. Graphene, due to its unique physical properties, has been used to reinforce and modify polyolefins. The preparation of graphene-modified polyolefins using a mechanochemical reaction induced by ball milling shearing shows high efficiency and promising application prospects.

[0004] Vertical stirred mills are increasingly widely used due to their advantages of producing fine-grained products and high energy efficiency. During operation, the material stratifies under the influence of gravity and centrifugal force, effectively preventing over-grinding. However, because the upper and lower layers experience different pressures, the wear rate of the stirring blades will differ. Excessive wear in any part of the stirring blade necessitates replacement of the entire blade, affecting its service life.

[0005] Secondly, the stirred mill has a large mass, resulting in a large starting torque. This large starting torque will affect the service life of the motor, reducer, stirring shaft, and bearing housing. It will also increase energy consumption. Summary of the Invention

[0006] This application proposes a grinding device for preparing graphene-modified polyolefin composite film materials. When using this vertical stirring mill, the excessively worn stirring unit can be replaced individually to reduce replacement costs, and the order of the stirring units can be adjusted from time to time to improve the service life of the stirring units. At the same time, starting the stirring units one by one also reduces the starting torque.

[0007] To achieve the above objectives, this application adopts the following technical solution: a grinding device for preparing graphene-modified polyolefin composite film materials, comprising a grinding cavity, a driving assembly installed on the top of the grinding cavity, the driving assembly connected to a driving shaft via a reducer, the end of the driving shaft extending into the grinding cavity, multiple sets of stirring units provided inside the grinding cavity, the multiple sets of stirring units connected end to end, each stirring unit comprising a rotating drum, the outer wall of the rotating drum being fixedly connected to a helical stirring blade, the multiple sets of helical stirring blades being able to be connected end to end to form a propeller blade, two rotating drums being connected together via a connecting shaft, the driving shaft comprising an axially extendable drive shaft, the drive shaft being connected to a driven shaft via a coupler, the drive shaft and the driven shaft being respectively provided with a holding gear and a starting gear, the inner wall of the rotating drum being provided with driven teeth corresponding to the starting gear and the holding gear, the starting gear and the holding gear being able to simultaneously mesh with two adjacent driven teeth, during startup, the starting gear and the holding gear moving axially, meshing with the driven teeth one by one, driving the stirring units to rotate one by one.

[0008] Furthermore, the drive shaft moves from top to bottom.

[0009] Furthermore, the upper and lower ends of the spiral stirring blade are respectively provided with a lower inclined surface and an upper inclined surface, with the upper inclined surface inclined upward and the lower inclined surface inclined downward.

[0010] Furthermore, the upper end of the spiral stirring blade is provided with a guide plate, which is fixedly connected to the spiral stirring blade. The guide plate has a larger lifting angle than the spiral stirring blade. The highest point of the guide plate is lower than the lowest point of the upper inclined surface, and the end of the guide plate coincides with the starting position of the lower inclined surface.

[0011] Furthermore, the connecting shaft is provided with ratchet teeth, and the inner wall of the rotating drum is provided with positioning blocks corresponding to the ratchet teeth. The connecting shaft can drive the rotating drum to rotate in one direction. When the positioning block and the ratchet teeth are in contact, the adjacent spiral stirring blades are connected end to end.

[0012] Furthermore, the distance L between the starting gear and the holding gear is greater than the length of the stirring unit, and the difference between L and the length of the stirring unit is less than the width of the holding gear. Each time the starting gear and the driven gear mesh, the starting gear meshes with the bottom of the driven gear, and the bottom of the holding gear meshes with the top of the driven gear. Before the drive shaft moves downward, the drive shaft moves upward and waits for a set time before moving to the next stirring unit, so that the starting gear does not disengage from the driven gear, and the holding gear disengages from the driven gear.

[0013] Furthermore, the connecting shaft is connected to the rotating drum via a flat key.

[0014] Furthermore, the upper part of the starting gear is provided with a conical friction head that can deform and retract. The coupler is a magnetic powder clutch. When the friction head enters the next stirring unit, the transmission torque of the coupler is reduced first. When the starting gear meshes with the next set of driven teeth, it recovers. The maintaining gear can mesh with the lowest driven teeth.

[0015] The beneficial effects of this invention are:

[0016] This application provides a grinding device for preparing graphene-modified polyolefin composite film materials. When using this vertical stirred mill, the excessively worn stirring unit can be replaced individually to reduce replacement costs, and the order of the stirring units can be adjusted from time to time to improve the service life of the stirring units and reduce the operating costs.

[0017] Meanwhile, during startup, the stirring units are driven sequentially, and the next stirring unit is driven only when the previous stirring unit is running stably. This greatly reduces the starting torque, improves the service life of the relevant equipment, and reduces energy consumption. Attached Figure Description

[0018] The accompanying drawings, which form part of this specification, illustrate embodiments disclosed in this application and, together with the specification, serve to explain the principles of the embodiments disclosed in this application.

[0019] Referring to the accompanying drawings and the following detailed description, the embodiments disclosed in this application can be understood more clearly, wherein:

[0020] Figure 1 This is a schematic diagram of the present invention;

[0021] Figure 2 This is a schematic diagram of multiple stirring units forming a whole in this invention;

[0022] Figure 3 This is a schematic diagram of the stirring unit in this invention;

[0023] Figure 4 This is a schematic diagram of the stirring unit and drive shaft in this invention.

[0024] In the diagram: 1. Grinding chamber; 2. Drive shaft; 21. Active shaft; 22. Driven shaft; 23. Coupler; 24. Starting gear; 25. Holding gear; 26. Friction head; 3. Drive assembly; 4. Stirring unit; 41. Rotary drum; 42. Spiral stirring blade; 43. Connecting shaft; 44. Racket; 45. Positioning block; 46. Positioning cone; 47. Driven tooth; 48. Upper inclined surface; 49. Lower inclined surface. Detailed Implementation

[0025] Example 1:

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0027] Please see Figures 1-2 A grinding device for preparing graphene-modified polyolefin composite film material is a vertical stirred mill, including a grinding chamber 1, which contains a mixture (not shown) and grinding balls. A drive assembly 3 is installed on the top of the grinding chamber 1. The drive assembly 3 is connected to a drive shaft 2 through a reducer. The drive shaft 2 extends into the grinding chamber 1 through the end of the grinding chamber 1. Multiple stirring units 4 are provided in the grinding chamber 1, and the multiple stirring units 4 are connected end to end to form a whole.

[0028] Please see Figures 3-4 The stirring unit 4 includes a rotating drum 41, with spiral stirring blades 42 fixedly connected to the outer wall of the rotating drum 41. The spiral stirring blades 42 are complete spirals with an integer number of turns. Multiple sets of spiral stirring blades 42 connected end to end form a propeller blade. The outer diameter of the connecting shaft 43 is smaller than the inner diameter of the rotating drum 41, allowing it to be inserted into the rotating drum 41. Two rotating drums 41 are connected together via the connecting shaft 43. The drive shaft 2 includes an axially extendable drive shaft 21, which is connected to a driven shaft 22 via a coupler 23. The drive shaft 21 and the driven shaft 22 are respectively provided with a holding gear 25 and a starting gear. 24. The inner wall of the rotating drum 41 is provided with driven teeth 47 corresponding to the starting gear 24 and the holding gear 25. When the holding gear 25 meshes with the driven teeth 47, the starting gear 24 can also mesh with the adjacent driven teeth 47. The drive shaft 21 is driven by hydraulic or pneumatic pressure and always maintains a transmission connection with the drive assembly 3 when moving. In this embodiment, the drive shaft 21 is connected to the hydraulic rod, and the hydraulic cylinder and piston rod always maintain a meshing state and rotate synchronously. The outer side of the hydraulic cylinder is provided with a gear and is connected to the reducer. The top of the hydraulic cylinder is connected to the external pressure source through a water-cooled ring.

[0029] During startup, the drive shaft 21 moves axially, either from bottom to top or from top to bottom. To reduce the starting torque, it is preferred to move from top to bottom. The starting gear 24 and the holding gear 25 mesh with the driven gear 47 one by one, driving the rotating drum 41 to rotate in sequence. During this process, the starting gear 24 is used to start the rotating drum 41 and make it start to rotate, while the holding gear 25 is used to maintain the rotation of the rotating drum 41 and maintain its working state.

[0030] Please see Figure 3Since adjacent stirring units 4 will rotate relative to each other, in order to avoid collisions between adjacent spiral stirring blades 42 and to ensure the movement of materials, the gap between two adjacent stirring units 4 cannot be too large. Therefore, the upper and lower ends of the spiral stirring blades 42 are respectively provided with a lower inclined surface 49 and an upper inclined surface 48, with the upper inclined surface 48 facing upward and the lower inclined surface 49 facing downward. The axial distance between the upper inclined surface 48 and the lower inclined surface 49 is large enough to prevent mutual collisions. At most, they will rub against each other on their inclined surfaces. The bottom spiral stirring blade 42 may not have an upper inclined surface 48, and the top spiral stirring blade 42 may not have a lower inclined surface 49.

[0031] To further facilitate the smooth movement of material at the junction of the two spiral mixing blades 42, a guide plate 46 is provided at the upper end of the spiral mixing blade 42. Except for the top spiral mixing blade 42, the guide plate 46 can be welded to the spiral mixing blade 42. The guide plate 46 has a larger lifting angle than the spiral mixing blade 42. The highest point of the guide plate 46 is lower than the lowest point of the upper inclined surface 48. The end of the guide plate 46 coincides with the starting position of the lower inclined surface 49. Because the guide plate 46 has a higher lifting angle, the material will "jump" when passing through this point and pass through the gap between the two mixing units 4. At the same time, the larger lifting angle here is also beneficial for crushing.

[0032] Please see Figure 3 and Figure 4 To ensure that the two stirring units 4 rotate at the same speed, the two spiral stirring blades 42 are connected end to end. The connecting shaft 43 is provided with ratchet 44, and the inner wall of the rotating drum 41 is provided with positioning blocks 45 corresponding to the ratchet 44, so that the connecting shaft 43 drives the rotating drum 41 to rotate in one direction. The connecting shaft 43 and the rotating drum 41 both rotate in the same direction. When the upper rotating drum 41 rotates faster, the rotating drum 41 rotates relative to the connecting shaft 43, and the connecting shaft 43 is not subjected to the force of the rotating drum 41. When the rotating drum 41 rotates faster, the rotating drum 41 rotates relative to the connecting shaft 43, which can drive the connecting shaft 43 to rotate. When the positioning block 45 and the ratchet 44 are in contact, the adjacent spiral stirring blades 42 are exactly connected end to end. In order to ensure the correspondence between the positions of the ratchet 44 and the positioning block 45, if there are multiple sets of ratchet 44 and positioning block 45, the two sets of ratchet 44 and positioning block 45 should be staggered in the axial direction.

[0033] The distance L between the starting gear 24 and the holding gear 25 is greater than the length of the stirring unit 4, and the difference between L and the length of the stirring unit 4 is less than the width of the holding gear 25. Each time the starting gear 24 and the driven gear 47 mesh, the starting gear 24 meshes with the bottom of the driven gear 47, and the bottom of the holding gear 25 meshes with the top of the driven gear 47. Before the drive shaft 2 moves downward, the drive shaft 2 moves upward and waits for a set time before moving to the next stirring unit 4. The starting gear 24 does not disengage from the driven gear 47, and the holding gear 25 disengages from the driven gear 47. The upper stirring unit 4 loses driving force, the rotation speed slows down, the ratchet 44 contacts the positioning block 45, and the adjacent spiral stirring blades 42 connect end to end.

[0034] Since the connecting shaft 43 has a transmission structure, in order to further reduce the replacement cost of the stirring unit 4, the connecting shaft 43 is connected to the rotating drum 41 by a flat key. When the stirring unit 4 needs to be replaced, only the external rotating drum 41 and the spiral stirring blade 42 are replaced. A dynamic seal is provided between the connecting shaft 43 and the rotating drum 41.

[0035] Since the starting gear 24 continues to rotate when disengaging from the previous driven gear 47, the driven shaft 22 and the starting gear 24 also generate considerable inertia. To avoid excessive impact force between the starting gear 24 and the driven gear 47, a conical friction head 26 is provided on the upper part of the starting gear 24. The friction head 26 is elastic and retractable to ensure that it can pass through the driven gear 47. The coupler 23 is a magnetic powder clutch that can actively reduce torque. When the friction head 26 enters the next stirring unit 4, the torque of the coupler 23 is reduced first. Under the frictional force of the friction head 26, the starting gear 24 gradually decelerates. When the starting gear 24 engages with the next set of driven gears 47, the coupler 23 continues to transmit torque to maintain the engagement of the gear 25 with the lowest driven gear 47. If there is insufficient space at the bottom, the driven shaft 22 can be configured as a telescopic type.

[0036] When starting the equipment, the starting gear 24 first meshes with the uppermost driven gear 47, driving the uppermost stirring unit 4 to rotate. Then it continues to move downwards, and the starting gear 24 meshes with the next driven gear 47. The holding gear 25 meshes with the first driven gear 47, causing the first stirring unit 4 to continue to rotate. The starting gear 24 drives the next stirring unit 4 to rotate, and the drive shaft 21 gradually moves downwards, eventually starting each stirring unit 4.

Claims

1. A grinding apparatus for preparing graphene-modified polyolefin composite film materials, comprising a grinding cavity (1), wherein a driving assembly (3) is mounted on the top of the grinding cavity (1), and the driving assembly (3) is connected to a driving shaft (2) via a reducer, the end of the driving shaft (2) extending through the grinding cavity (1) into the grinding cavity (1), characterized in that, The grinding chamber (1) is equipped with multiple sets of stirring units (4), which are connected end to end. Each stirring unit (4) includes a rotating drum (41). The outer wall of the rotating drum (41) is fixedly connected with a spiral stirring blade (42). The multiple sets of spiral stirring blades (42) can be connected end to end to form a propeller blade. Two rotating drums (41) are connected together by a connecting shaft (43). The connecting shaft (43) is connected to one of the rotating drums (41) by a flat key and can drive the other rotating drum (41) to rotate in one direction. The drive shaft (2) includes an axially extendable drive shaft (21). The drive shaft (21) is connected to the driven shaft (22) via a coupler (23). The drive shaft (21) and the driven shaft (22) are respectively provided with a holding gear (25) and a starting gear (24). The inner wall of the rotating drum (41) is provided with driven teeth (47) corresponding to the starting gear (24) and the holding gear (25). The starting gear (24) and the holding gear (25) can simultaneously mesh with two adjacent driven teeth (47). When starting, the starting gear (24) and the holding gear (25) move axially and mesh with the driven teeth (47) one by one, driving the stirring unit (4) to rotate one by one. The spiral stirring blade (42) has a lower inclined surface (49) and an upper inclined surface (48) at its upper and lower ends, respectively. The upper inclined surface (48) is inclined upward and the lower inclined surface (49) is inclined downward. The upper end of the spiral stirring blade (42) is provided with a guide plate (46). The guide plate (46) is fixedly connected to the spiral stirring blade (42). The guide plate (46) has a larger lifting angle than the spiral stirring blade (42). The highest point of the guide plate (46) is lower than the lowest point of the upper inclined surface (48). The end of the guide plate (46) coincides with the starting position of the lower inclined surface (49). The connecting shaft (43) is provided with a ratchet (44). The inner wall of the rotating cylinder (41) is provided with a positioning block (45) corresponding to the ratchet (44). When the positioning block (45) and the ratchet (44) are in contact, the adjacent spiral stirring blades (42) are exactly connected end to end.

2. The grinding apparatus for preparing graphene-modified polyolefin composite film materials according to claim 1, characterized in that, The drive shaft (21) moves from top to bottom.

3. The grinding apparatus for preparing graphene-modified polyolefin composite film materials according to claim 1, characterized in that, The distance L between the starting gear (24) and the holding gear (25) is greater than the length of the stirring unit (4), and the difference between L and the length of the stirring unit (4) is less than the width of the holding gear (25). Each time the starting gear (24) and the driven gear (47) mesh, the starting gear (24) meshes with the bottom of the driven gear (47), and the bottom of the holding gear (25) meshes with the top of the driven gear (47). Before the drive shaft (2) moves downward, the drive shaft (2) moves upward and waits for a set time before moving to the next stirring unit (4), so that the starting gear (24) does not disengage from the driven gear (47), and the holding gear (25) disengages from the driven gear (47).

4. The grinding apparatus for preparing graphene-modified polyolefin composite film materials according to claim 1, characterized in that, The upper part of the starting gear (24) is provided with a conical friction head (26) that can deform and retract. The coupler (23) is a magnetic powder clutch. When the friction head (26) enters the next stirring unit (4), the transmission torque of the coupler (23) is reduced first. When the starting gear (24) meshes with the next set of driven teeth (47), it recovers. The holding gear (25) can mesh with the lowest driven teeth (47).

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