CN109129997B - Fully automatic recycled plastic granulation production line - Google Patents

Abstract

The invention discloses a full-automatic regenerated plastic granulating production line, which comprises a feed box and is characterized in that: the material box is connected with a material distribution box through a material loading auger, the material loading auger is electrically connected with a full box anti-overflow device, and the material distribution box is sequentially connected with a constant-speed discharging device, a first pushing auger, a melt filtering device, a melt connecting pipe, a defoaming mixing hopper, a second pushing auger, a plastic extruding device, a cooling water tank, a dewatering device, a particle forming machine, a particle screening device, a particle collecting device and a particle collecting hopper. The invention has reasonable and compact structure, so that the regenerated plastic granulation production line can basically realize automatic production, manual intervention is not needed basically, manual labor can be reduced greatly, dust emission and smoke emission can be reduced better by the omnibearing dust collection, emission reduction and filtration arrangement, and high-quality regenerated plastic particles can be produced cleanly.

Description

Fully automatic recycled plastic granulation production line

Technical Field

The invention relates to the field of recycled plastic processing machinery, in particular to a fully automatic recycled plastic granulation production line.

Background technique

Recycled plastic granules belong to the category of plastic granules. Recycled plastic granules are plastics produced by recycling used new materials or waste plastics through a screw machine, and then cut into granular plastic granules by a pelletizer.

Recycled plastic particles are mainly graded according to the different raw materials used and the characteristics of the processed plastic particles. They are generally divided into first, second and third grade materials, and their quality decreases in turn. Among them, third grade materials refer to raw materials that have been used twice or more. The processed particles are not very good in terms of elasticity, toughness and other aspects. The source of third grade materials is plastic waste in industry and life. Plastic waste that is everywhere in life can be recycled into particles and reused. Generally, third grade materials can only be used for injection molding. Although the application scope of third grade materials is limited, it will still significantly reduce the degree of plastic pollution in society and reduce resource waste. Third grade materials come from plastic waste in industry or life. They need to be initially screened, large pieces of debris are removed, and then broken into plastic fragments for the next step of granulation. On the one hand, plastic recycling and reuse is a requirement of an environmentally friendly and low-energy society. On the other hand, the traditional recycled plastic particle production line is purely manually loaded. A large amount of waste recycled plastic particles will raise a lot of dust during the loading process. The dust comes from dust and fine plastic particles generated during the crushing process. These raised dusts are easily inhaled directly by workers, causing great damage to health and causing great pollution to the environment. The industry needs a fully automatic recycled plastic granulation production line that can minimize manual operations, reduce dust, and produce recycled plastic particles in a clean manner.

Summary of the invention

The purpose of the present invention is to overcome the shortcomings of the above-mentioned traditional technology and provide a fully automatic recycled plastic granulation production line which can reduce manual operation, reduce dust, and can cleanly produce recycled plastic particles.

The purpose of the present invention is achieved through the following technical measures:

The fully automatic recycled plastic granulation production line includes a material box, which is characterized in that: the material box is connected to a distribution box through a feeding auger, the feeding auger is electrically connected to a full box overflow prevention device, the full box overflow prevention device is arranged on the upper part of the distribution box, the lower part of the distribution box is connected to a constant speed feeding device, the lower part of the constant speed feeding device is connected to a first propulsion auger, the first propulsion auger is equipped with a first constant temperature heating device, the outlet of the first propulsion auger is connected to a molten material filtering device, the molten material filtering device is connected to a molten material connecting pipe, and the molten material connecting pipe is equipped with a connecting pipe constant temperature device, The molten material connecting pipe is connected to a defoaming mixing hopper, a defoaming adding device is provided on the defoaming mixing hopper, a second propulsion auger is connected to the lower end of the defoaming mixing hopper, a dual-control constant temperature device is mounted on the second propulsion auger, a plastic extrusion device is connected to the outlet of the second propulsion auger, the plastic extrusion device is connected to a cooling water tank, the cooling water tank is connected to a dewatering device, the dewatering device is connected to a particle forming machine, the particle forming machine is connected to a particle screening device, the particle screening device is connected to a particle collecting device, and the particle collecting device is connected to a particle collecting hopper.

As a specific preferred embodiment, the device also includes a smoke collection and purification device, which includes a smoke fan, a smoke purification device and a plurality of dust hoods. The smoke fan is connected to the smoke purification device and the dust hood by a dust suction pipe. The dust hood is at least arranged in one or more of the material distribution box, the middle of the first propulsion auger, the defoaming mixing hopper, the middle of the second propulsion auger, and the plastic extrusion device. The middle of the first propulsion auger and the middle of the second propulsion auger are respectively provided with smoke exhaust holes. The smoke generated by the melted plastic is discharged to the dust hood through the smoke exhaust holes and collected and purified by the smoke collection and purification device. A dust hood is provided at each structure where smoke is generated and overflowed on the production line. The smoke fan attracts the smoke discharged by each device on the production line through the dust hood, and is purified by the smoke purification device, so that the entire production line meets very high environmental protection standards, realizes green and environmentally friendly production, and truly protects the environment. The smoke purification device adopts the purification equipment currently available on the market, and the specific structure is a well-known technology and is not repeated.

As a specific preferred embodiment, the full box overflow prevention device includes a vertical plate and a distance sensor, the vertical plate is hinged on the vertical plate crankshaft, the vertical plate crankshaft is placed on the distribution box through a bracket, the lower part of the vertical plate is located between the center and the inner wall of the distribution box, the distance sensor is installed accordingly to the vertical plate, and after the distance sensor senses the movement of the vertical plate, it sends a message to cause the feeding auger to stop feeding.

As a specific preferred embodiment, the constant speed unloading device includes a unloading auger and a unloading stepping motor driving the unloading auger, the unloading auger inlet is connected with the lower outlet of the material distribution box, the unloading auger outlet is connected with the inlet of the first propulsion auger, and the unloading auger pushes the plastic into the first propulsion auger at a constant speed.

As a specific preferred mode, the molten material filtering device comprises a filter body, the filter body comprises a first shell and a second shell, a material cavity is arranged between the first shell and the second shell, a filter plate is arranged in the material cavity, the filter plate divides the material cavity into an entry cavity and a discharge cavity, the entry cavity is communicated with the outlet of the first propulsion auger, the discharge cavity is communicated with the molten material connecting pipe, a molten material extrusion wheel is arranged in the entry cavity, the molten material extrusion wheel pushes the melted plastic through the filter plate into the discharge cavity, the molten material extrusion wheel is connected to the extrusion wheel driving motor, a waste residue discharge pipe is connected to the lower part of the entry cavity, a waste residue discharge switch is arranged on the waste residue discharge pipe, and a waste residue constant temperature device is installed on the waste residue discharge pipe. The melted plastic is pushed to the entry cavity by the first propulsion auger, the melted material extrusion wheel further squeezes the melted plastic, and extrude the melted plastic through the filter plate to the discharge cavity, and the mixed insoluble particles in the plastic will be blocked by the filter plate and pushed and deposited in the waste residue discharge pipe at the lower part. When there are a lot of insoluble particle residues in the waste residue discharge pipe, the waste residue discharge switch is turned on to discharge the residue. The filtered plastic will be more uniform and cleaner, the quality of the finished product will be higher, and the product quality will be greatly improved.

As a specific preferred embodiment, the defoaming adding device includes a quantitative feeding device, a defoaming particle hopper and a defoaming material pipe. The quantitative feeding device includes a feeder and a defoaming feeding stepper motor. The feeder inlet is connected to the defoaming particle hopper outlet, the feeder outlet is connected to the defoaming material pipe, the defoaming material pipe is connected to the defoaming mixing hopper, and a feeding wheel is installed inside the feeder. The defoaming feeding stepper motor drives the feeding wheel to rotate at a constant speed to release the defoaming agent into the defoaming mixing hopper. The molten plastic is mixed with the defoaming particles through the defoaming mixing hopper, which can improve the quality of the plastic and eliminate the gas in the plastic. Defoaming particles are a commonly used plastic additive. The internal structure of the feeder is a well-known technology and will not be described in detail.

As a specific preferred embodiment, the dual-control thermostatic device includes a second heating device and a water-cooled thermostatic device, the second heating device includes a plurality of annular heaters, the water-cooled thermostatic device includes a plurality of annular water jackets, the annular water jackets and the annular heaters are staggered and mounted on the second propulsion auger, the annular water jacket pipeline is connected with a circulating water pump and a cooling water pool, and the circulating water pump drives the cooling water to circulate between the annular water jacket and the cooling water pool. The second heating device and the water-cooled thermostatic device in the dual-control thermostatic device correspond to different working periods respectively. During normal assembly line operation, the second propulsion auger pushes the plastic to extrude the plastic strip through the plastic extrusion device. The auger will generate a large amount of heat due to severe pressure and friction, which will further increase the temperature of the plastic, resulting in gas precipitation, plastic denaturation, and serious quality degradation in the plastic. In the present invention, the circulating water in the annular water jacket is used for cooling, and the temperature of the plastic in the auger is maintained at the most suitable temperature, which greatly improves the quality of the plastic and improves the product quality. When the production line is to start operation from the cooling state, the residual plastic in the auger will hinder the smooth start of the equipment. The second heating device is used to heat the plastic to the melting temperature, making the equipment easier to start.

As a specific preferred embodiment, the dewatering device includes a dewatering trough, and water absorbing blocks are respectively provided at both ends of the dewatering trough, and the water absorbing blocks protrude from the bottom surface of the trough of the dewatering trough. A vibration roller is provided in the middle of the dewatering trough, and the vibration roller is connected to a vibration drive motor. The outer periphery of the vibration roller is provided with a striking protrusion protruding from the surface, and an air-drying device is provided at one end of the dewatering trough facing the particle forming machine. The plastic strips are extruded by the plastic extrusion device and fall into the cooling water tank for cooling and forming. The temperature of the formed plastic strips drops significantly during the process of passing through the cooling water tank, but they will be contaminated with water, which affects the casting and processing of the finished particles. The dewatering device of the present invention can completely remove the water on the plastic strips and improve the quality of the finished plastic particles. The plastic strips that have initially absorbed water through the water absorbing blocks will encounter the vibration rollers. The rotating vibration rollers continuously hit the plastic strips through the striking protrusions on the surface to form vibrations, and shake off the residual water on the plastic strips. Finally, while the water absorbing blocks absorb the residual water again, the air-drying device blows air quickly to completely dry the plastic strips, and the plastic strips entering the particle forming machine are completely free of water. The plastic strips entering the dewatering device still have a relatively high temperature, generally up to 50-70°C, are soft in texture, and will not break in the vibration of the impact. The dewatering device of the present invention can significantly improve the quality of the finished particles and the quality of the finished product.

As a specific preferred embodiment, the particle screening device includes a vibrating screen, the vibrating screen is provided with sieve holes for allowing plastic particles to pass through, the vibrating screen is placed on an elastic bracket, a vibrating motor is provided on the vibrating screen, a receiving tray is provided below the vibrating screen, the bottom height of the receiving tray decreases from one end close to the particle forming machine to the far end, and a discharge port is provided at the end of the receiving tray with a lower height.

As a specific preferred embodiment, the particle collection device includes a blower, the blower is connected to a wind feeding pipe, a receiving hopper is provided below the discharge port of the receiving tray, the lower opening of the receiving hopper is connected to the wind feeding pipe, and the end of the wind feeding pipe points to the inside of the particle collection hopper. A discharge pipe is provided on the side of the particle collection hopper, and a ton bag is placed through a receiving bracket, and the discharge pipe points to the ton bag. The wind blows the plastic particles into the particle collection hopper, and after being buffered in the particle collection hopper, the particles slide into the ton bag through the discharge pipe along its inner wall, thereby avoiding the bouncing and flying of particles caused by wind blowing, so as to completely recycle the manufactured plastic particles and avoid loss and waste.

Due to the adoption of the above technical scheme, compared with the prior art, the advantages of the present invention are: the present invention discloses a fully automatic recycled plastic granulation production line, which, through a reasonable and compact structure, enables the recycled plastic granulation production line to basically realize automatic production, basically without manual intervention, and can greatly reduce labor, and the all-round dust suction, emission reduction and filtering settings can better reduce dust and smoke emissions, and can cleanly produce high-quality recycled plastic particles.

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a fully automatic recycled plastic granulation production line of the present invention.

2 is a schematic structural diagram of the full box overflow prevention device on the material distribution box in the present invention in normal operation state.

3 is a schematic structural diagram of the state where the filling is stopped by the overflow prevention device on the material distribution box in the present invention.

FIG4 is a schematic structural diagram of a constant speed feeding device in the present invention.

FIG5 is a schematic structural diagram of the melt filtering device of the present invention.

FIG6 is a schematic diagram of the structure of the defoaming adding device of the present invention.

FIG. 7 is a schematic diagram of the structure of the water removal device of the present invention.

FIG8 is a schematic diagram of the structure of the vibrating roller of the dewatering device of the present invention.

FIG9 is a schematic diagram of the structure of the particle screening device of the present invention.

Detailed ways

Embodiment: As shown in Figures 1 to 9, a fully automatic recycled plastic granulation production line includes a material box 1, the material box 1 is connected to a distribution box 3 through a feeding auger 2, the feeding auger 2 is electrically connected to a full box overflow prevention device 31, the full box overflow prevention device 31 is arranged on the upper part of the distribution box 3, the lower part of the distribution box 3 is connected to a constant speed feeding device 6, the lower part of the constant speed feeding device 6 is connected to a first propulsion auger 7, the first propulsion auger 7 is equipped with a first constant temperature heating device 8, the outlet of the first propulsion auger 7 is connected to a melt filtering device 9, the melt filtering device 9 is connected to a melt connecting pipe 10, the melt connecting pipe 10 is equipped with a connecting pipe constant temperature device 11, the melt connecting pipe The pipe 10 is connected to a defoaming mixing hopper 12, on which a defoaming adding device 13 is provided, a second propulsion auger 14 is connected to the lower end of the defoaming mixing hopper 12, a dual-control constant temperature device 17 is mounted on the second propulsion auger 14, a plastic extrusion device 18 is connected to the outlet of the second propulsion auger 14, the plastic extrusion device 18 is connected to a cooling water tank 19, the cooling water tank 19 is connected to a dewatering device 20, the dewatering device 20 is connected to a particle forming machine 21, the particle forming machine 21 is connected to a particle screening device 22, the particle screening device 22 is connected to a particle collecting device 23, and the particle collecting device 23 is connected to a particle collecting hopper 24.

In this embodiment, the production line also includes a smoke collection and purification device, which includes a smoke fan, a smoke purification device and a plurality of dust hoods 4. The smoke fan is connected to the smoke purification device and the dust hood 4 by a dust suction pipe 5. The dust hood 4 is at least arranged in the material distribution box 3, the middle of the first propulsion auger 7, the defoaming mixing hopper 12, the middle of the second propulsion auger 14 and the plastic extrusion device 18. The middle of the first propulsion auger 7 and the middle of the second propulsion auger 14 are respectively provided with smoke exhaust holes, and the smoke generated by the melted plastic is discharged to the dust hood 4 through the smoke exhaust holes and collected and purified by the smoke collection and purification device. A dust hood 4 is provided at each structure where smoke is generated and overflowed on the production line. The smoke fan attracts the smoke discharged by each device on the production line through the dust hood 4, and is purified by the smoke purification device, so that the entire production line reaches a very high environmental protection standard, realizes green and environmentally friendly production, and truly protects the environment. The smoke purification device adopts the purification equipment currently available on the market, and the specific structure is a well-known technology, which will not be repeated. The smoke fan and smoke purification device are not shown in the accompanying drawings.

As shown in Figures 2 and 3, the full box overflow prevention device 31 includes a vertical plate 311 and a distance sensor 312. The vertical plate 311 is hinged on the vertical plate shaft 313. The vertical plate shaft 313 is placed on the distribution box 3 through a bracket. The lower part of the vertical plate 311 is located between the center and the inner wall of the distribution box 3. The distance sensor 312 is installed corresponding to the vertical plate 311. After the distance sensor 312 senses the movement of the vertical plate 311, it sends a message to stop the feeding auger 2 from feeding.

As shown in FIG4 , the constant speed unloading device 6 comprises an unloading auger 61 and an unloading stepping motor 62 driving the unloading auger 61. The inlet of the unloading auger 61 is connected to the lower outlet of the material distribution box 3, and the outlet of the unloading auger 61 is connected to the inlet of the first propulsion auger 7. The unloading auger 61 pushes the plastic into the first propulsion auger 7 at a constant speed. The spiral blades in the first propulsion auger 7 are not shown in the figure.

As shown in FIG5 , the molten material filtering device 9 comprises a filter body, and the filter body comprises a first shell 91 and a second shell 92, a material cavity 93 is provided between the first shell 91 and the second shell 92, a filter plate 94 is provided in the material cavity 93, and the filter plate 94 separates the material cavity into an entrance cavity and a discharge cavity, the entrance cavity is communicated with the outlet of the first propulsion auger 7, and the discharge cavity is communicated with the molten material connecting pipe 10, a molten material extrusion wheel 95 is provided in the entrance cavity, and the molten material extrusion wheel 95 pushes the melted plastic through the filter plate 94 into the discharge cavity, the molten material extrusion wheel 95 is transmission-connected with an extrusion wheel drive motor 97, and the extrusion wheel drive motor 97 is connected to the molten material extrusion wheel 95 through a reducer 96, and a waste residue discharge pipe 98 is connected to the lower part of the entrance cavity, a waste residue discharge switch 100 is provided on the waste residue discharge pipe 98, and a waste residue constant temperature device 99 is mounted on the waste residue discharge pipe 98. The melted plastic is pushed into the cavity by the first push auger 7, and the melt extrusion wheel 95 further squeezes the melted plastic and squeezes the melted plastic into the discharge cavity through the filter plate 94, while the mixed insoluble particles in the plastic will be blocked by the filter plate 94 and pushed and deposited into the waste residue discharge pipe 98 at the bottom. When there are a lot of insoluble particles in the waste residue discharge pipe 98, the waste residue discharge switch 100 is turned on to discharge the residue. The filtered plastic will be more uniform and clean, and the finished product quality will be higher, and the product quality will be greatly improved.

As shown in Figure 6, the defoaming adding device 13 includes a quantitative feeding device 132, a defoaming particle hopper 131 and a defoaming material pipe 133. The quantitative feeding device 132 includes a feeder and a defoaming feeding stepper motor. The feeder inlet is connected to the outlet of the defoaming particle hopper 131, and the feeder outlet is connected to the defoaming material pipe 133. The defoaming material pipe 133 is connected to the defoaming mixing hopper 12. A feeding wheel is installed inside the feeder. The defoaming feeding stepper motor drives the feeding wheel to rotate at a constant speed to release the defoaming agent into the defoaming mixing hopper 12. The molten plastic is mixed with the defoaming particles through the defoaming mixing hopper 12, which can improve the quality of the plastic and eliminate the gas in the plastic. Defoaming particles are a commonly used plastic additive. The internal structure of the feeder is a well-known technology and is not described in detail.

As shown in Figure 1, the dual-control thermostatic device 17 includes a second heating device and a water-cooled thermostatic device. The second heating device 15 includes a plurality of annular heaters 15, and the water-cooled thermostatic device includes a plurality of annular water jackets 16. The annular water jackets 16 and the annular heaters 15 are staggered and sleeved on the second propulsion auger 14. The annular water jacket 16 pipeline is connected with a circulating water pump and a cooling water pool. The circulating water pump drives the cooling water to circulate between the annular water jacket 16 and the cooling water pool. The second heating device and the water-cooled thermostatic device in the dual-control thermostatic device 17 correspond to different working periods respectively. During normal assembly line operation, the second propulsion auger 14 pushes the plastic to extrude through the plastic extrusion device 18 to form a plastic strip. The auger will generate a large amount of heat due to severe pressure and friction, which will further increase the temperature of the plastic, resulting in gas precipitation in the plastic, plastic denaturation, and serious quality degradation. In the present invention, the circulating water in the annular water jacket 16 is used to cool down and maintain the plastic temperature in the auger at the most suitable temperature, which greatly improves the quality of the plastic and improves the product quality. When the production line is to start operation from a cooling state, the plastic remaining in the auger will hinder the smooth start of the equipment. The annular heater 15 of the second heating device is heated to the melting temperature of the plastic, making it easier to start the equipment.

As shown in Figures 7 and 8, the dewatering device 20 comprises a dewatering trough 201, which is arranged on a dewatering trough frame 202. Water absorbing blocks 203 with water absorbing effect are respectively arranged at both ends of the dewatering trough 201, and the water absorbing blocks 203 protrude from the bottom surface of the trough 201. A vibration roller 204 is arranged in the middle of the dewatering trough 201, and the vibration roller 204 is connected to a vibration driving motor 204. The outer periphery of the vibration roller 204 is provided with a striking protrusion 205 protruding from the surface. The end of the dewatering trough 201 facing the particle forming machine 21 is provided with an air drying device 206. The plastic strips extruded by the plastic extrusion device 18 fall into the cooling water tank 19 for cooling and forming. The temperature of the formed plastic strips drops significantly during the process of passing through the cooling water tank 19, but they will be contaminated with water, which affects the casting processing and use of the finished particles. The dewatering device 20 of the present invention can completely remove the water on the plastic strips and improve the quality of the finished plastic particles. The plastic strip that has been initially absorbed water by the water absorbing block 203 will encounter the vibration roller 204. The rotating vibration roller 204 continuously hits the plastic strip through the hitting protrusions 205 on the surface to form vibration, and shakes off the residual water on the plastic strip. Finally, while the water absorbing block 203 absorbs the residual water again, the air drying device 206 completely dries the plastic strip by rapid air blowing, and the plastic strip entering the particle forming machine 21 is completely free of water. The plastic strip entering the dewatering device 20 still has a relatively high temperature, generally up to 50-70°C, and is soft in texture and will not break in the vibration of the hitting. The use of the dewatering device 20 in the present invention can significantly improve the quality of the finished particles and the quality of the finished product.

As shown in FIG9 , the particle screening device 22 includes a vibrating screen 221, the vibrating screen 221 is provided with sieve holes for allowing plastic particles to pass through, the vibrating screen 221 is placed on an elastic bracket 222, a vibration motor 223 is provided on the vibrating screen 221, and a receiving tray 224 is provided below the vibrating screen 221. The bottom heights of the vibrating screen 221 and the receiving tray 224 decrease from one end close to the particle forming machine 21 to the far end, and a discharge port is provided at the lower end of the receiving tray 224.

As shown in FIG. 9 , the particle collection device 23 includes a blower 231, and the blower 231 is connected to a wind feeding pipe 232. A receiving hopper 233 is provided below the discharge port of the receiving tray 224, and the lower opening of the receiving hopper 233 is connected to the wind feeding pipe 232, and the end of the wind feeding pipe 232 points to the inside of the particle collection hopper 24. A discharge pipe is provided on the side of the particle collection hopper 24, and a ton bag is placed through a receiving bracket, and the discharge pipe points to the ton bag. The wind blows the plastic particles into the particle collection hopper 24, and after being buffered in the particle collection hopper 24, it slides into the ton bag through the discharge pipe along its inner wall, thereby avoiding the bouncing and flying of particles caused by wind blowing, so as to completely recycle the manufactured plastic particles and avoid loss and waste.

Claims (5)

1. A fully automatic recycled plastic granulation production line, comprising a material box, characterized in that: the material box is connected to a material distribution box through a feeding auger, the feeding auger is electrically connected to a full box overflow prevention device, the full box overflow prevention device is arranged on the upper part of the material distribution box, the lower part of the material distribution box is connected to a constant speed feeding device, the lower part of the constant speed feeding device is connected to a first propulsion auger, the first propulsion auger is equipped with a first constant temperature heating device, the outlet of the first propulsion auger is connected to a melt filtering device, the melt filtering device is connected to a melt connecting pipe, the melt connecting pipe is connected to A defoaming mixing hopper is connected, a defoaming adding device is arranged on the defoaming mixing hopper, a second propulsion auger is connected to the lower end of the defoaming mixing hopper, a dual-control constant temperature device is mounted on the second propulsion auger, a plastic extrusion device is connected to the outlet of the second propulsion auger, the plastic extrusion device is connected to a cooling water tank, the cooling water tank is connected to a dewatering device, the dewatering device is connected to a particle forming machine, the particle forming machine is connected to a particle screening device, the particle screening device is connected to a particle collecting device, and the particle collecting device is connected to a particle collecting hopper; The full box overflow prevention device includes a vertical plate and a distance sensor, the vertical plate is hinged on the vertical plate shaft, the vertical plate shaft is placed on the material distribution box through a bracket, the lower part of the vertical plate is located between the center of the upper opening of the material distribution box and the inner wall, the distance sensor is installed corresponding to the vertical plate, and the distance sensor sends a message to stop the feeding auger after sensing the movement of the vertical plate; The molten material filtering device comprises a filter body, the filter body comprises a first shell and a second shell, a material cavity is arranged between the first shell and the second shell, a filter plate is arranged in the material cavity, the filter plate separates the material cavity into an inlet cavity and a discharge cavity, the inlet cavity is communicated with the outlet of the first propulsion auger, the discharge cavity is communicated with the molten material connecting pipe, a molten material extrusion wheel is arranged in the inlet cavity, the molten material extrusion wheel pushes the melted plastic through the filter plate into the discharge cavity, the molten material extrusion wheel is transmission-connected with an extrusion wheel driving motor, a waste residue discharge pipe is connected to the lower part of the inlet cavity, a waste residue discharge switch is arranged on the waste residue discharge pipe, and a waste residue constant temperature device is mounted on the waste residue discharge pipe; The dual-control thermostatic device includes a second heating device and a water-cooled thermostatic device, the second heating device includes a plurality of annular heaters, the water-cooled thermostatic device includes a plurality of annular water jackets, the annular water jackets and the annular heaters are staggered and sleeved on the second propulsion auger, the annular water jacket pipeline is connected to a circulating water pump and a cooling water pool, and the circulating water pump drives the cooling water to circulate between the annular water jacket and the cooling water pool; It also includes a smoke collection and purification device, which includes a smoke fan, a smoke purification device and a plurality of dust hoods, wherein the smoke fan is connected to the smoke purification device and the dust hood by a dust suction pipe, and the dust hood is at least arranged at one or more of the material distribution box, the middle part of the first propulsion auger, the defoaming mixing hopper, the middle part of the second propulsion auger, and the plastic extrusion device; The constant speed unloading device includes an unloading auger and an unloading stepping motor driving the unloading auger, the unloading auger inlet is connected with the lower outlet of the material distribution box, the unloading auger outlet is connected with the first propulsion auger inlet, and the unloading auger pushes the plastic into the first propulsion auger at a constant speed. 2. The fully automatic recycled plastic granulation production line according to claim 1 is characterized in that: the defoaming addition device includes a quantitative feeding device, a defoaming particle hopper and a defoaming material pipe, the quantitative feeding device includes a feeder and a defoaming feeding stepper motor, the feeder inlet is connected with the defoaming particle hopper outlet, the feeder outlet is connected with the defoaming material pipe, the defoaming material pipe is connected with the defoaming mixing hopper, the feeder is equipped with a feeding wheel, and the defoaming feeding stepper motor drives the feeding wheel to rotate at a constant speed to release the defoaming agent into the defoaming mixing hopper. 3. The fully automatic recycled plastic granulation production line according to claim 1 is characterized in that: the dewatering device includes a dewatering trough, water absorption blocks are respectively provided at both ends of the dewatering trough, the water absorption blocks protrude from the bottom surface of the trough, a vibration roller is provided in the middle of the dewatering trough, the vibration roller is connected to a vibration drive motor, and the outer periphery of the vibration roller is provided with striking protrusions protruding from the surface, and an air-drying device is provided at one end of the dewatering trough facing the granule forming machine. 4. The fully automatic recycled plastic granulation production line according to any one of claims 1 to 3 is characterized in that: the particle screening device includes a vibrating screen, the vibrating screen is provided with sieve holes for allowing plastic particles to pass through, the vibrating screen is placed on an elastic bracket, the vibrating screen is provided with a vibration motor, a receiving tray is provided below the vibrating screen, the bottom height of the receiving tray decreases from one end close to the particle forming machine to the far end, and a discharge port is provided at the end of the receiving tray with a lower height. 5. The fully automatic recycled plastic granulation production line according to claim 4 is characterized in that: the particle collection device includes a blower, the blower is connected to a wind feeding pipe, a receiving hopper is provided below the discharge port of the receiving tray, the lower opening of the receiving hopper is connected to the wind feeding pipe, and the end of the wind feeding pipe points to the inside of the particle collection hopper.