A composite plastic processing equipment for producing recycled plastic products

Abstract

This invention discloses a production equipment for recycled plastic products through composite plastic processing, relating to the field of recycled plastic granule preparation technology. It includes a main extruder body and a secondary extruder. The secondary extruder includes a frame, a mixing drum mounted on the frame, and a conveying screw inside the mixing drum. The conveying screw has a keyway, and a drive shaft has a plug inserted into and slidably connected to the keyway. The intermittent transmission assembly includes a protective shell fixedly mounted on the frame. When a transient drop in melt pressure occurs at the discharge end of the secondary extruder, a third motor rotates and drives the ball screw to rotate forward, causing the conveying screw to continuously rotate and feed material while simultaneously sliding axially towards the discharge end for compensation. This actively compresses the volume at the front end of the mixing drum to smooth out pressure fluctuations. This invention solves the industry defects of poor plasticizing quality in single-machine systems, fixed cavities in traditional dual-machine equipment, passive pressure compensation, and poor cleaning effects by enabling the conveying screw to move axially.

Description

Technical Field

[0001] This invention relates to the field of recycled plastic pellet preparation technology, and in particular to a recycled plastic product manufacturing equipment for composite plastic processing. Background Technology

[0002] Composite recycled plastics are recycled materials obtained from waste plastics through melting, mixing, and regranulation. They are widely used in the extrusion molding of profiles, pipes, sheets, and other products. Compared to virgin plastic raw materials, composite recycled plastics have more complex sources, resulting in greater fluctuations in melt viscosity, poorer flowability, and higher impurity content. This places stringent requirements on the pressure stabilization, cleaning capabilities, and adaptability of extrusion molding equipment.

[0003] Currently, recycled plastic extrusion molding mainly employs two modes: single-extrusion and dual-extrusion. Single-extrusion relies on only one extruder to complete the melting, mixing, and molding of raw materials. While the equipment structure is simple, the plasticization uniformity is poor, making it difficult to adapt to the stable processing of high-impurity composite recycled plastics. Dual-extrusion, on the other hand, uses the main extruder to handle the melting and plasticization of the raw materials, while the auxiliary extruder is responsible for the pressure stabilization, conveying, and molding of the melt. Compared to single-extrusion equipment, this significantly improves the plasticization uniformity of the material and the basic quality of the molded product.

[0004] However, existing dual-machine linkage extrusion equipment still has the following shortcomings in actual production:

[0005] Firstly, the conveying screw of a traditional auxiliary extruder only has a fixed-axis rotation feeding function and cannot achieve axial movement. During the final stages of batch production or when the main extruder's feed fluctuates, the material inside the auxiliary extruder's mixing drum becomes deficient, causing a rapid drop in melt pressure at its discharge end (die). Lacking an active, mechanical volumetric compensation structure, the pressure can only be restored by passively adjusting the screw speed through the electronic control system. However, this method suffers from lag and low compensation accuracy, easily leading to intermittent die discharge, uneven product wall thickness, and even a surge in scrap rates.

[0006] Secondly, impurities and low-melting-point components in the composite recycled plastic remain on the inner wall of the mixing drum for a long time and carbonize at high temperatures, forming "dead material" that is difficult to remove. Since the conveying screw cannot move axially, it cannot actively push out the residual material adhering to the drum wall. It is necessary to manually stop the machine periodically for disassembly and cleaning, resulting in poor production continuity, high operation and maintenance costs, and low overall equipment efficiency.

[0007] Third, the existing equipment has a single detection and control strategy, relying on a single sensor (such as a level gauge or pressure sensor) for post-judgment. It cannot simultaneously achieve pre-judgment of material shortage and real-time closed-loop feedback of pressure, resulting in untimely or false triggering of pressure compensation. Furthermore, it only achieves passive pressure compensation through electrical speed regulation in the control cabinet, without a mechanical adaptive compensation structure for pressure compensation, resulting in uneven wire output at the discharge end. Summary of the Invention

[0008] The purpose of this invention is to provide a production equipment for recycled plastic products through composite plastic processing, in order to solve the technical problems mentioned in the background art, such as passive compensation of melt pressure at the discharge end of existing extrusion equipment, delayed response, and poor cleaning effect due to carbonization of residual material accumulation inside the mixing drum.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a recycled plastic product manufacturing equipment for composite plastic processing, comprising a main extruder body and a control cabinet, and further comprising:

[0010] The auxiliary extruder includes a frame, a second motor mounted on the frame, a second gearbox mounted on the frame, a drive shaft mounted inside the second gearbox, a mixing drum mounted on the frame, a conveying screw mounted inside the mixing drum, a keyway on the conveying screw, and a sliding insert mounted on the drive shaft.

[0011] A protective shell is installed on the frame, and a third motor is installed inside the protective shell. A ball screw located inside the protective shell is coaxially fixed at the output end of the third motor. The ball screw is rotatably connected to the protective shell. When a transient drop in melt pressure occurs at the discharge end of the auxiliary extruder, the third motor rotates and drives the ball screw to rotate forward, so that the conveying screw, while maintaining continuous forward rotation and feeding, slides axially towards the discharge end to actively compress the volume at the front end of the mixing drum and suppress pressure fluctuations.

[0012] Preferably, the protective shell is provided with a heavy-duty linear guide rail that is axially parallel to the drive shaft corresponding to the auxiliary extruder. The ball screw is threaded with a movable seat, which is slidably mounted on the heavy-duty linear guide rail to counteract the off-center overturning torque.

[0013] Preferably, an annular seat is fixedly assembled at the end of the movable seat facing the conveying screw, and a heavy-duty thrust roller bearing assembly is embedded in the annular seat. The annular seat is connected to a rotating seat through the heavy-duty thrust roller bearing assembly.

[0014] Preferably, the outer wall of the conveying screw is coaxially and fixedly connected to the rotating seat, which is used to transfer the extreme melt back pressure borne by the front of the conveying screw to the moving seat and isolate the high-speed rotation of the conveying screw.

[0015] Preferably, the production equipment further includes a detection component, which includes a capacitive level sensor and a high-temperature melt pressure sensor; the capacitive level sensor is installed at the feed end of the mixing drum, and a die head is provided at the discharge end of the mixing drum; the high-temperature melt pressure sensor is installed at the discharge end of the mixing drum near the die head; the capacitive level sensor, the high-temperature melt pressure sensor, the third motor, and the second motor are all electrically connected to the control cabinet.

[0016] Preferably, the second motor is connected to the second gearbox corresponding to the auxiliary extruder, driving the transmission shaft to rotate.

[0017] Preferably, the control cabinet has a built-in threshold judgment module for receiving material shortage signals or melt low pressure signals and triggering the third motor to turn the ball screw.

[0018] Preferably, the control cabinet has a built-in reset module. After the material is discharged, the system controls the second motor to maintain its original forward rotation direction, while the reset module only controls the third motor to be energized and rotate in the reverse direction, driving the ball screw to reverse and causing the conveying screw to push the moving seat backward, thereby realizing the axial reset of the conveying screw.

[0019] Preferably, a first motor is installed on the main extruder body, a first gearbox is installed on the main extruder body, the first motor is connected to the first gearbox on the main extruder body, the discharge end of the main extruder body is connected to the feed end of the mixing drum, and the first motor is electrically connected to the control cabinet.

[0020] Preferably, the main extruder body only has a raw material melting and metering conveying structure, which is used to continuously convey molten composite recycled plastic to the auxiliary extruder.

[0021] The beneficial effects of this invention are:

[0022] 1. When the high-temperature melt pressure sensor detects a pressure drop, the control system drives the ball screw to rotate, causing the entire conveying screw to slide axially towards the discharge end, creating a "piston pressure compensation" effect. This actively compresses the front volume, instantly smoothing out pressure fluctuations. Compared to traditional electronic speed control, this system offers faster response and higher precision, effectively avoiding intermittent discharge and uneven product wall thickness. During the compensation stroke, especially towards the end of the batch, the axially moving conveying screw forcibly pushes the impurity-containing residual melt remaining on the inner wall of the mixing drum and at the front end, actively pushing the adhered and accumulated carbonized residue towards the die head and discharging it. This combines "pressure compensation" and "cleaning action" into one. This significantly reduces the frequency of manual disassembly and cleaning, lowers maintenance costs, and improves production continuity. A capacitive level sensor is installed at the feed end to pre-judge material shortages, and a high-temperature melt pressure sensor is installed at the discharge end to monitor molding pressure in real time. Both are electrically connected to the control cabinet and have a built-in threshold judgment module. This dual detection mechanism avoids the lag of a single sensor, ensuring the timeliness and accuracy of pressure compensation actions and preventing false triggering. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0024] Figure 2 This is a cross-sectional plan view of the auxiliary extruder in this invention.

[0025] Figure 3 This is an exploded view of the drive shaft and conveying screw in this invention.

[0026] Figure 4 This is a schematic diagram of the structure of the third motor and the ball screw in this invention.

[0027] Figure 5 This is a schematic diagram of the moving seat and heavy-duty linear guide rail in this invention.

[0028] Figure 6 This is a cross-sectional view of the annular seat and the rotating seat in this invention.

[0029] Figure 7 This is a schematic diagram of the rotating seat in this invention.

[0030] Figure 8 This is a schematic diagram of the transmission shaft and key in this invention.

[0031] The attached figures are labeled as follows: 1. Main extruder body; 101. Frame; 102. Second motor; 103. Second gearbox; 104. Drive shaft; 1041. Insert; 105. Mixing drum; 106. Conveying screw; 1061. Keyway; 107. Die head; 108. First gearbox; 2. Auxiliary extruder; 3. Control cabinet; 4. First motor; 5. Protective shell; 501. Third motor; 503. Ball screw; 6. Moving seat; 7. Annular seat; 8. Rotating seat; 9. Capacitive level sensor; 10. High-temperature melt pressure sensor; 11. Discharge pipe. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and 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.

[0033] Example:

[0034] Composite recycled plastics are recycled materials obtained from waste plastics through melting, mixing, and regranulation. They are widely used in the extrusion molding of profiles, pipes, sheets, and other products. Compared to virgin plastic raw materials, composite recycled plastics have more complex sources, resulting in greater fluctuations in melt viscosity, poorer flowability, and higher impurity content. This places stringent requirements on the pressure stabilization, cleaning capabilities, and adaptability of extrusion molding equipment.

[0035] Currently, recycled plastic extrusion molding mainly employs two modes: single-extrusion and dual-extrusion. Single-extrusion relies on only one extruder to complete the melting, mixing, and molding of raw materials. While the equipment structure is simple, the plasticization uniformity is poor, making it difficult to adapt to the stable processing of high-impurity composite recycled plastics. Dual-extrusion, on the other hand, uses the main extruder to handle the melting and plasticization of the raw materials, while the auxiliary extruder is responsible for the pressure stabilization, conveying, and molding of the melt. Compared to single-extrusion equipment, this significantly improves the plasticization uniformity of the material and the basic quality of the molded product.

[0036] However, existing dual-machine linkage extrusion equipment still has the following shortcomings in actual production:

[0037] Traditional auxiliary extruders only have a fixed-axis rotating feeding function for the conveying screw and cannot achieve axial movement. During the final stages of batch production or when the main extruder's feed fluctuates, the material inside the auxiliary extruder's mixing drum becomes deficient, causing a rapid drop in melt pressure at the discharge end (die). Lacking an active, mechanical volumetric compensation structure, the pressure can only be restored by passively adjusting the screw speed through the electronic control system. However, this method suffers from lag and low compensation accuracy, easily leading to intermittent die discharge, uneven product wall thickness, and even a surge in scrap rates.

[0038] Impurities and low-melting-point components in composite recycled plastics remain on the inner wall of the mixing drum for a long time and carbonize at high temperatures, forming "dead material" that is difficult to remove. Since the conveying screw cannot move axially, it cannot actively push away the residual material adhering to the drum wall. It is necessary to manually stop the machine periodically for disassembly and cleaning, resulting in poor production continuity, high operation and maintenance costs, and low overall equipment efficiency.

[0039] Furthermore, the existing equipment has a single detection and control strategy, relying on a single sensor (such as a level gauge or pressure sensor) for post-judgment. It cannot simultaneously achieve pre-judgment of material shortage and real-time closed-loop feedback of pressure, resulting in untimely or false triggering of pressure compensation.

[0040] To resolve the above technical issues, please refer to Figures 1 to 8As shown in the figure, this embodiment provides a recycled plastic product manufacturing equipment for composite plastic processing, including a main extruder body 1 and a control cabinet 3, and also includes an auxiliary extruder 2. The auxiliary extruder 2 includes a frame 101, a second motor 102 mounted on the frame 101, a second gearbox 103 mounted on the frame 101, a drive shaft 104 mounted inside the second gearbox 103, a mixing drum 105 mounted on the frame 101, a conveying screw 106 mounted inside the mixing drum 105, a keyway 1061 formed on the conveying screw 106, and a drive shaft 104 provided with a keyway 1061. The inner sliding insert 1041; a protective shell 5 is provided on the frame 101, and a third motor 501 is provided inside the protective shell 5. The output end of the third motor 501 is coaxially fixed with a ball screw 503 located inside the protective shell 5. The ball screw 503 is rotatably connected to the protective shell 5. When the melt pressure drops transiently at the discharge end of the auxiliary extruder 2, the third motor 501 rotates and drives the ball screw 503 to rotate forward, so that the conveying screw 106, while maintaining continuous forward rotation and feeding, slides axially towards the discharge end to actively compress the volume of the front end of the mixing drum 105 and suppress pressure fluctuations.

[0041] Inside the protective shell 5, there is a heavy-duty linear guide parallel to the axial direction of the drive shaft 104 corresponding to the auxiliary extruder 2. The heavy-duty linear guide consists of multiple smooth guide posts that are slidably connected to the moving seat 6. The moving seat 6 is threaded onto the ball screw 503 and is slidably mounted on the heavy-duty linear guide to counteract the off-center overturning torque. An annular seat 7 is fixedly mounted on one end of the moving seat 6 facing the conveying screw 106. A heavy-duty thrust roller bearing assembly is embedded in the annular seat 7. The annular seat 7 is connected to a rotating seat 8 through the heavy-duty thrust roller bearing assembly. The outer wall of the conveying screw 106 is coaxially fixedly connected to the rotating seat 8 to transfer the extreme melt back pressure borne by the front of the conveying screw 106 to the moving seat 6 and to isolate the high-speed rotation of the conveying screw 106.

[0042] The production equipment also includes a detection component, which includes a capacitive level sensor 9 and a high-temperature melt pressure sensor 10. The capacitive level sensor 9 is installed at the feed end of the mixing drum 105, and a die head 107 is provided at the discharge end of the mixing drum 105. The high-temperature melt pressure sensor 10 is installed at the discharge end of the mixing drum 105 near the die head 107. The capacitive level sensor 9, the high-temperature melt pressure sensor 10, the third motor 501, and the second motor 102 are all electrically connected to the control cabinet 3. The second motor 102 is connected to the second gearbox 103 corresponding to the auxiliary extruder 2, driving the transmission shaft 104 to rotate. The control cabinet 3 has a built-in threshold judgment module, which is used to receive material shortage signals or melt low pressure signals and trigger the third motor 501 to turn the ball screw 503.

[0043] The control cabinet 3 has a built-in reset module. After the material is discharged, the system controls the second motor 102 to keep its original forward rotation direction unchanged. The reset module only controls the third motor 501 to be energized and rotate in the reverse direction, driving the ball screw 503 to reverse, so that the conveying screw 106 pushes the moving seat 6 backward, thereby realizing the axial reset of the conveying screw 106.

[0044] The main extruder body 1 is equipped with a first motor 4 and a first gearbox 108. The first motor 4 is connected to the first gearbox 108 on the main extruder body 1. The discharge end of the main extruder body 1 is connected to the feed end of the mixing drum 105. The first motor 4 is electrically connected to the control cabinet 3. The main extruder body 1 only has a raw material melting and quantitative feeding structure, which is used to continuously feed molten composite recycled plastic to the auxiliary extruder 2.

[0045] When the equipment is started, the control cabinet 3 connected to the main extruder body 1 outputs a control signal to drive the first motor 4 and the second motor 102 connected to the main extruder body 1 to run synchronously. The first motor 4 drives the corresponding conveying screw 106 of the main extruder body 1 to rotate through the corresponding first gearbox 108, which heats, melts and continuously mixes the input composite recycled plastic raw material. The discharge end of the main extruder body 1 is equipped with a discharge pipe 11. The discharge outlet of the discharge pipe 11 is inserted into the feed end of the auxiliary extruder 2, and the plasticized molten recycled plastic material is continuously conveyed to the feed inlet of the auxiliary extruder 2 through the discharge end of the main extruder body 1 and the discharge pipe 11. Then, it enters the mixing drum 105 of the auxiliary extruder 2 through the feed inlet of the auxiliary extruder 2.

[0046] Compared to single-machine extrusion equipment, this dual-machine linkage equipment realizes separate operations for plasticizing and pressure stabilization. The main extruder body 1 focuses on raw material mixing and plasticizing, while the auxiliary extruder 2 focuses on discharge pressure stabilization, which greatly improves the plasticizing uniformity of recycled plastic materials, reduces bubbles and delamination defects, and the basic molding quality of the product is better than that of single-machine equipment, enabling small-batch continuous production.

[0047] As the equipment starts up, the output shaft of the second motor 102 drives the transmission shaft 104 inside the second gearbox 103 to rotate continuously on a fixed axis. The plug 1041 fixed at the end of the transmission shaft 104 engages with the keyway 1061 at the tail of the conveying screw 106. The plug 1041 rotates synchronously with the transmission shaft 104. The torque is transmitted through the keyway 1061 to drive the conveying screw 106 to rotate inside the mixing drum 105. The conveying screw 106 continuously pushes the molten material toward the die head 107 to complete the conventional extrusion molding operation.

[0048] Control cabinet 3 controls the third motor 501 to remain in a de-energized state. Since the power is physically cut off, the ball screw 503 remains stationary. The conveying screw 106 relies solely on the sliding fit between the insert 1041 and the keyway 1061 to perform high-speed rotation feeding within the mixing drum 105. The movable seat 6 threaded onto the ball screw 503, the annular seat 7 fixed at the end of the movable seat 6, the rotating seat 8 embedded inside the annular seat 7, and the conveying screw 106 all remain in their initial positions.

[0049] Meanwhile, the capacitive level sensor 9 at the feed end of the mixing drum 105 collects the internal material inventory signal in real time, and the high-temperature melt pressure sensor 10 near the die head 107 at the discharge end collects the melt forming pressure signal in real time. The detection data is continuously transmitted to the control cabinet 3. When the molten material pressure at the discharge port is insufficient, the high-temperature melt pressure sensor 10 detects the pressure drop at the die head 107 and sends a signal to the control cabinet 3, thereby causing the control cabinet 3 to control the third motor 501 to start. The third motor 501 rotates and drives the ball screw 503 to rotate.

[0050] During the rotation of the ball screw 503, the moving seat 6 is driven to slide axially along the inner wall of the protective shell 5 toward the die head 107 by the threaded transmission structure. The moving seat 6 resists the off-center load by the heavy-duty linear guide rail. The moving seat 6 drives the annular seat 7 fixed at the end to move axially synchronously. The rotating seat 8 rotatably connected inside the annular seat 7 moves axially synchronously. At the same time, the rotating seat 8 can rotate freely inside the annular seat 7, completely isolating the axial sliding motion of the moving seat 6 from the rotational motion of the conveying screw 106.

[0051] While the conveying screw 106 continuously rotates and feeds material, the sliding engagement between the tail keyway 1061 and the end insert 1041 of the drive shaft 104, as well as the ball screw 503 driving the moving seat 6 to move axially, pushes the annular seat 7 and the rotating seat 8 to move axially, so that the rotating seat 8 drives the conveying screw 106 to move towards the discharge end of the auxiliary extruder 2. The side of the conveying screw 106 near the discharge end is a plunger-type structure, and the discharge port of the mixing drum 105 is a melt space with the same shape as the plunger-type structure of the conveying screw 106, which is used to accommodate the plunger-type structure.

[0052] When the high-temperature melt pressure sensor 10 detects insufficient molten material discharge pressure, the conveying screw 106 pushes the plunger structure a certain distance into the melt space, causing part of the melt space to be occupied by the plunger structure. This enhances the discharge pressure of the molten material at the outlet end. When the high-temperature melt pressure sensor 10 detects stable molten material discharge pressure, it immediately sends a signal to the control cabinet 3, causing the control cabinet to stop the third motor 501 from rotating. The third motor 501 can self-lock and rotate in both directions when not in use, thus maintaining stable molten material discharge pressure. The material is discharged from the stirring drum 105 through the plunger structure and the melt space. This action creates a "piston pressure compensation" effect, instantly smoothing out pressure drops and enabling monitoring of the end pressure. This prevents insufficient molten material pressure at the outlet, which could lead to uneven discharge. The axial position of the conveying screw 106 is adjusted in real time according to the pressure to supplement pressure and maintain stable pressure at the discharge end.

[0053] It should be noted that if the supplementary pressure during this process is continuous discharge and the pressure at the end is insufficient, the conveying screw 106 is moved axially within a small range to reduce the melt space, thereby adjusting the discharge pressure of the molten material at the end. During continuous discharge, the third motor 501 does not reverse to avoid the conveying screw 106 moving in the opposite direction, which would increase the melt space. If the molten material is about to be completely discharged, the conveying screw 106 is made to squeeze the last material directly out of the melt space through a plunger structure. Only after the molten material is completely discharged can the third motor 501 reverse to reset the conveying screw 106.

[0054] Meanwhile, the axial movement distance of the conveying screw 106 is changed according to the pressure monitored in real time by the high-temperature melt pressure sensor 10, and there is a maximum distance limit to avoid the plunger structure from impacting the discharge port. The maximum distance can only allow the plunger structure to fill the plunger space, and the conveying screw 106 can only move to the maximum distance during the final discharge stage. After all the material is discharged, the axial movement of the conveying screw reaches the maximum movement distance, and the control cabinet 3 immediately controls the third motor 501 to reverse, so as to avoid the plunger structure from impacting the discharge port, lift and compensate for the falling melt pressure, and ensure that the die head 107 discharges continuously and evenly during the discharge. At the same time, the axially forward-moving conveying screw 106 forcibly pushes the residual melt containing impurities inside the mixing drum 105, automatically completing the cleaning operation inside the mixing drum 105 and preventing the accumulation of carbonized dead material.

[0055] After the molten material at the end is discharged, the high-temperature melt pressure sensor 10 detects that the melt pressure has returned to the preset threshold and transmits the signal to the control cabinet 3. The reset module built into the control cabinet 3 then issues a command to trigger the reset logic. At this time, the second motor 102 is strictly prohibited from reversing, as reversing the second motor 102 will cause severe backflow and damage. Therefore, the second motor 102 continues to rotate in the forward direction, and the control cabinet 3 controls the third motor 501 to rotate in the reverse direction, so that the third motor 501 drives the ball screw 503 to rotate in the reverse direction synchronously. The ball screw 503 drives the moving seat 6 to move in the reverse direction, so that the conveying screw 106 accurately returns to the balance position, ensuring the uniformity of the wire diameter.

[0056] By creating a keyway 1061 at the tail of the conveying screw 106 and a sliding insert 1041 at the end of the drive shaft 104, a sliding transmission pair is formed. Simultaneously, in conjunction with the third motor 501 and the ball screw 503, when the high-temperature melt pressure sensor 10 installed at the discharge end of the mixing drum 105 detects a transient drop in melt pressure within the plunger-type space, the control cabinet 3 triggers the third motor 501 to rotate and drives the ball screw 503 to rotate forward. This drives the moving seat 6, the annular seat 7, and the rotating seat 8 to continuously feed material while maintaining forward rotation of the conveying screw 106. At the same time, the entire assembly slides axially toward the discharge end die head 107, actively compressing the front volume of the mixing drum 105 and smoothing pressure fluctuations in milliseconds. This mechanical active compensation structure overcomes the shortcomings of traditional electronic speed regulation passive compensation, such as delayed response and low precision, and effectively avoids problems such as discontinuous discharge and uneven product thickness. During continuous material conveying, the conveying screw 106 can only move axially toward the discharge end, and the third motor 501 does not reverse but only performs pressure compensation. Only at the end of the discharge period, after the molten material has been discharged, can the third motor 501 reverse and reset the conveying screw 106.

[0057] During the forward axial sliding of the conveying screw 106 due to pressure compensation, it satisfies the real-time pressure detection and compensation during the discharge process. At the end of the discharge, its spiral edge forcibly pushes the impurity-containing residual melt retained on the inner wall and front end of the mixing drum 105, and actively pushes the adhering and accumulated carbonized residue towards the die head 107 through the plunger structure and discharges it. This design combines the pressure compensation action and the cleaning action into one, eliminating the need for manual shutdown for disassembly and cleaning, greatly reducing equipment maintenance time and production costs, and improving production continuity.

[0058] A capacitive level sensor 9 is installed at the feed end of the mixing drum 105 for pre-judgment of material shortage; a high-temperature melt pressure sensor 10 is installed at the discharge end near the die head 107 for real-time and accurate detection of melt pressure. Both are electrically connected to the control cabinet 3, which has a built-in threshold judgment module that simultaneously receives material shortage signals and melt low pressure signals, avoiding lag or false triggering by a single sensor.

[0059] During continuous material conveying, when the pressure returns to the preset threshold, the reset module built into the control cabinet 3 only controls the third motor 501 to stop, preventing the conveying screw 106 from axially displacing, while keeping the second motor 102 in its original forward direction unchanged. After the material discharge is completed, the third motor 501 is controlled to reverse and drive the ball screw 503 to reverse, so that the ball screw 503 pulls the moving seat 6 in the opposite direction, thereby realizing the axial reset of the conveying screw 106.

[0060] Inside the protective shell 5, a heavy-duty linear guide rail parallel to the axis of the drive shaft 104 is installed, and the movable seat 6 is slidably mounted on it, effectively offsetting the off-center overturning torque generated by the extreme melt back pressure on the front of the conveying screw 106. At the same time, an annular seat 7 is fixed at the end of the movable seat 6, and a heavy-duty thrust roller bearing assembly is embedded in the annular seat 7. The rotating seat 8 is rotatably connected to the annular seat 7 through the bearing assembly. The tail of the conveying screw 106 is coaxially fixed with the rotating seat 8, which precisely isolates the high-speed rotational motion of the conveying screw 106 from the axial sliding motion of the movable seat 6, so that they do not interfere with each other, reduce component wear, and ensure long-term stable operation of the equipment under high pressure and high speed conditions.

[0061] In summary, this invention systematically solves the problems of insufficient material pressure at the discharge end, poor cleaning effect, and control lag in existing recycled plastic extrusion equipment during the discharge process by using axial slip compensation of the conveying screw 106, capacitive material level sensor 9, closed-loop detection of high-temperature melt pressure sensor 10, and optimized transmission force structure moving seat 6, ring seat 7, and rotating seat 8. This significantly improves the molding quality of recycled plastic products, the automation level of the equipment, and the continuous production capacity.

[0062] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A production equipment for recycled plastic products through composite plastic processing, comprising a main extruder body (1) and a control cabinet (3), characterized in that, Also includes: A secondary extruder (2) includes a frame (101), a second motor (102) is mounted on the frame (101), a second gearbox (103) is mounted on the frame (101), a drive shaft (104) is mounted inside the second gearbox (103), a mixing drum (105) is mounted on the frame (101), a conveying screw (106) is mounted inside the mixing drum (105), a keyway (1061) is provided on the conveying screw (106), and a plug (1041) that can slide in the keyway (1061) is mounted on the drive shaft (104). A protective shell (5) is provided on the frame (101), and a third motor (501) is provided inside the protective shell (5). The output end of the third motor (501) is coaxially fixed with a ball screw (503) located inside the protective shell (5). The ball screw (503) is rotatably connected to the protective shell (5). When the melt pressure drops transiently at the discharge end of the auxiliary extruder (2), the third motor (501) rotates and drives the ball screw (503) to rotate forward, so that the conveying screw (106) can slide axially towards the discharge end while maintaining continuous forward rotation feeding, so as to actively compress the volume of the front end of the mixing drum (105) and suppress pressure fluctuations. The protective shell (5) is provided with a heavy-duty linear guide rail that is axially parallel to the drive shaft (104) corresponding to the auxiliary extruder (2). The ball screw (503) is threaded with a movable seat (6). The movable seat (6) is slidably mounted on the heavy-duty linear guide rail to counteract the off-center overturning torque. The movable seat (6) is fixedly equipped with an annular seat (7) at one end facing the conveying screw (106). The annular seat (7) is fitted with a heavy-duty thrust roller bearing assembly. The annular seat (7) is connected to a rotating seat (8) through the heavy-duty thrust roller bearing assembly. The outer wall of the conveying screw (106) is coaxially fixedly connected to the rotating seat (8) to transmit the extreme melt back pressure borne by the front of the conveying screw (106) to the moving seat (6) and to isolate the high-speed rotation of the conveying screw (106). The production equipment also includes a detection component, which includes a capacitive level sensor (9) and a high-temperature melt pressure sensor (10). The capacitive level sensor (9) is installed at the feed end of the mixing drum (105), and a die head (107) is provided at the discharge end of the mixing drum (105). The high-temperature melt pressure sensor (10) is installed at the discharge end of the mixing drum (105) near the die head (107). The capacitive level sensor (9), the high-temperature melt pressure sensor (10), the third motor (501), and the second motor (102) are all electrically connected to the control cabinet (3).

2. The equipment for producing recycled plastic products from composite plastics according to claim 1, characterized in that: The second motor (102) is connected to the second gearbox (103) corresponding to the auxiliary extruder (2) and drives the transmission shaft (104) to rotate.

3. The equipment for producing recycled plastic products from composite plastics according to claim 1, characterized in that: The control cabinet (3) has a built-in threshold judgment module, which is used to receive material shortage signal or melt low pressure signal and trigger the third motor (501) to turn the ball screw (503) to rotate.

4. The equipment for producing recycled plastic products from composite plastics according to claim 1, characterized in that: The control cabinet (3) has a built-in reset module. After the material is discharged, the system controls the second motor (102) to keep the original forward running direction unchanged. The reset module only controls the third motor (501) to be energized and rotate in the reverse direction, driving the ball screw (503) to reverse, so that the conveying screw (106) pushes the moving seat (6) backward, thereby realizing the axial reset of the conveying screw (106).

5. The equipment for producing recycled plastic products from composite plastics according to claim 1, characterized in that: The main extruder body (1) is equipped with a first motor (4) and a first gearbox (108). The first motor (4) is connected to the first gearbox (108) on the main extruder body (1). The discharge end of the main extruder body (1) is connected to the feed end of the mixing drum (105). The first motor (4) is electrically connected to the control cabinet (3).

6. The equipment for producing recycled plastic products from composite plastics according to claim 1, characterized in that: The main extruder body (1) only has a raw material melting and quantitative feeding structure, which is used to continuously feed molten composite recycled plastic to the auxiliary extruder (2).

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