Extrusion device capable of removing high boiling point impurity particles and impurity particle removal method

Abstract

The present application relates to an extrusion device capable of removing high-boiling-point impurity particles and a method for removing impurity particles. The extrusion device capable of removing high-boiling-point impurity particles comprises an extrusion barrel, an extrusion screw, a screw drive unit and a material heating unit. The extrusion screw is arranged in the extrusion barrel, and the material heating unit is arranged on the extrusion barrel, which can heat the material in the extrusion barrel into a molten state. The extrusion barrel is provided with a solvent injection unit and a solvent extraction unit. The solvent injection unit can pressurize and inject a solvent for dissolving high-boiling-point impurity particles into the extrusion barrel so that the solvent remains in a liquid state in the extrusion barrel. The solvent extraction unit is arranged behind the solvent injection unit and is used to extract the solvent mixed in the material from the extrusion barrel, which can improve the removal effect and removal efficiency of high-boiling-point impurity particles in materials such as plastic materials. The method for removing high-boiling-point impurity particles of the present application uses the extrusion device capable of removing high-boiling-point impurity particles of the present application.

Description

Technical Field

[0001] The present application relates to the field of extrusion granulation equipment, and in particular to an extrusion device capable of removing high-boiling-point impurity particles. In addition, the present application also relates to a method for removing high-boiling-point impurity particles. Background Art

[0002] Different types of plastic materials, especially various recycled waste plastic materials, are usually processed into plastic granules before being processed into plastic products, which is convenient for packaging and transportation of plastic materials. When granulating plastic granules, the plastic material is usually heated into a molten state, extruded and plasticized by an extruder, extruded through a template, and then cut into granules by a granulator. With the widespread use of plastic products, extrusion granulators have also been increasingly widely used in the industry.

[0003] Different plastic products have different requirements for the purity of plastic materials. In order to meet the processing needs of different plastic products, it is usually necessary to remove impurities in plastic materials before processing plastic particles. Different removal methods are usually used for impurities with different characteristics: for low-boiling impurities with a boiling point lower than the decomposition temperature of plastic, the method of reducing pressure and heating is usually used to remove impurities in plastic materials; for granular impurities with larger particle sizes, the method of filtering in the molten state of the plastic material is usually used to remove impurities in the plastic material; for impurities that can be dissolved in a specific solvent, the method of soaking the plastic material in the solvent is usually used to remove impurities in the plastic material. By removing impurities in plastic materials, the relevant properties of plastic products can be significantly improved, and the quality of plastic products, especially plastic products made from recycled waste plastic materials, can be improved.

[0004] The high-boiling-point impurity particles in existing plastic materials are mostly removed by soaking the plastic materials in a suitable solvent, taking advantage of the solubility of the impurity particles. However, the impurity particles are usually solidified inside the plastic material. In order to allow more impurity particles to dissolve in the solvent, the plastic material is usually extruded and pelletized in a molten state to form a thin sheet, and then the sheet is soaked for a long time. Not only is the removal process complicated, but the impurity removal time is also very long, and the removal efficiency is very low. The existing method of removing high-boiling-point impurity particles from plastic materials is usually carried out before the extrusion process of the plastic material, and then extrusion granulation is carried out after the impurity particles are removed. The process path is long, which restricts the granulation efficiency of the plastic material. Summary of the invention

[0005] In order to improve the removal effect and efficiency of high-boiling-point impurity particles in materials such as plastic materials, the present application provides an extrusion device and an impurity particle removal method that can remove high-boiling-point impurity particles.

[0006] The extrusion device provided in the present application for removing high boiling point impurity particles adopts the following technical solution:

[0007] An extrusion device capable of removing high-boiling-point impurity particles comprises an extrusion barrel, an extrusion screw, a screw driving unit and a material heating unit, wherein the extrusion screw is arranged in the extrusion barrel so that the material can be pushed from a feed port at one side end to a discharge port at the other end under the drive of the screw driving unit, the material heating unit is arranged on the extrusion barrel so that the material in the extrusion barrel can be heated into a molten state, the extrusion barrel is provided with a solvent injection unit and a solvent extraction unit, the solvent injection unit can pressurize and inject a solvent for dissolving high-boiling-point impurity particles into the extrusion barrel so that the solvent remains in a liquid state in the extrusion barrel, and the solvent extraction unit is arranged behind the solvent injection unit and can extract the solvent mixed in the material from the extrusion barrel.

[0008] By adopting the above technical scheme, the solvent can be injected into the material in a molten state by using the solvent injection unit and the solvent outlet unit arranged on the extrusion barrel, and fully mixed with the material under the action of the extrusion screw, so that the impurity particles mixed in the material can fully contact with the solvent, so that the impurity particles can be quickly and efficiently dissolved in the solvent and discharged through the solvent outlet unit, thereby improving the removal effect and removal efficiency of the impurity particles; by injecting the solvent into the extrusion barrel under pressure, the boiling temperature of the solvent can be increased, so that the solvent can remain liquid at the melting temperature of the material, thereby improving the solvent's ability to dissolve impurity particles and improving the removal effect of impurity particles.

[0009] In a specific possible implementation scheme, a solvent injection port is provided on the extrusion barrel, and the solvent injection unit includes a solvent filling pump, a pressure container and a solvent heating mechanism. The solvent filling pump is connected to the pressure container and can inject a solvent of a set pressure into the pressure container. The solvent heating mechanism is arranged in the pressure container to heat the solvent in the pressure container. The pressure container is connected to the solvent injection port to inject the solvent into the extrusion barrel through the solvent injection port.

[0010] By adopting the above technical scheme, using the solvent filling pump and pressure vessel in the solvent injection unit, a stable high-pressure state of the solvent can be formed, which is beneficial to increasing the boiling point of the solvent; using the solvent heating mechanism in the solvent injection unit, the temperature of the solvent can be increased before the solvent is injected into the material in the molten state, avoiding the solvent causing the adjacent materials to cool rapidly and solidify, thereby improving the plasticization effect of the material and the effect of mixing with the solvent.

[0011] In a specific embodiment, the solvent injection unit further comprises a flow control mechanism, which is disposed at the connection between the pressure container and the solvent injection port so as to control the flow rate of the solvent injected into the extrusion barrel.

[0012] By adopting the above technical solution, the flow control mechanism arranged at the connection between the pressure vessel and the solvent injection port can be used to control the amount of solvent injected into the extrusion barrel, thereby controlling the amount of high-boiling point impurity particles that can be dissolved by the solvent and the amount of solvent that needs to be separated from the material. While ensuring that the amount of high-boiling point impurity particles remaining in the material meets the design requirements, the plasticizing effect of the material in the extrusion barrel is guaranteed.

[0013] In a specific possible implementation scheme, the extrusion barrel includes a solvent outlet, and the solvent outlet unit includes a solvent outlet chamber, a reverse pushing screw and a reverse screw driving mechanism. One end of the solvent outlet chamber is connected to the solvent outlet, and the reverse pushing screw is arranged in the solvent outlet chamber and can push the material to move toward the solvent outlet under the reverse screw driving mechanism. The other end of the solvent outlet chamber is provided with a solvent discharge outlet.

[0014] By adopting the above technical scheme, the reverse pushing screw arranged in the solvent outlet chamber can be used to reversely push the material flowing into the solvent outlet chamber through the solvent outlet under the action of high pressure, thereby preventing the material from flowing to the solvent outlet at the other end of the solvent outlet chamber. The solvent mixed in the material can flow through the gap between the reverse pushing screw and the solvent outlet chamber due to its very low viscosity, flow toward the solvent outlet, and flow out through the solvent outlet, thereby realizing the separation of the solvent from the material.

[0015] In a specific embodiment, a solvent outlet heating device is provided on the side wall of the solvent outlet chamber adjacent to one end of the extrusion cylinder.

[0016] By adopting the above technical scheme, using the extraction heating device arranged on the side wall of one end of the solvent extraction chamber adjacent to the extrusion barrel, the material in the solvent extraction chamber can be continuously heated to prevent the material from solidifying due to temperature drop after leaving the extrusion barrel, thereby preventing the reverse driving screw from pushing the material to flow in the direction of the extrusion barrel, and the material in the extrusion barrel continuously flowing into the solvent extraction chamber, thereby ensuring the material flow performance and the extraction effect of the solvent in the material.

[0017] In a specific feasible implementation scheme, a transmission chamber and an adjustment chamber are arranged between the solvent derivation chamber and the reverse screw drive mechanism, a transmission screw is arranged in the transmission chamber, an output shaft of the reverse screw drive mechanism extends into the transmission chamber, and is drivingly connected to the transmission screw through a gear, a spline sleeve and a screw mounting seat are arranged in the adjustment chamber, the screw mounting seat is fixed in the adjustment chamber, the spline sleeve is supported on the screw mounting seat, a rotating shaft of the reverse push screw is rotatably connected to the adjustment chamber, and an end portion extends into the screw mounting seat and is spline-connected to one end of the spline sleeve, one end of the transmission screw extends into the adjustment chamber and is spline-connected to the other end of the spline sleeve.

[0018] By adopting the above technical solution, the transmission screw arranged in the transmission chamber can reliably transmit the rotational driving force between the reverse screw driving mechanism and the reverse pushing screw, so that the two reverse pushing screws can be reliably driven to rotate synchronously by one reverse screw driving mechanism; by using the spline sleeve connected between the transmission screw and the reverse pushing screw, the driving force can be transmitted between the transmission screw and the reverse pushing screw while ensuring that the reverse pushing screw has sufficient positional freedom.

[0019] In a specific possible implementation manner, a hydraulic valve is provided between the solvent derivation unit and the solvent derivation outlet, and a pressure gauge is provided at the solvent discharge outlet.

[0020] By adopting the above technical solution, the flow of the material between the extruder and the solvent outlet can be monitored by using a hydraulic valve arranged between the solvent outlet unit and the solvent outlet, so as to facilitate the reverse push of the screw to adjust the rotation speed and ensure the sufficient discharge of the solvent in the material; the pressure gauge arranged at the solvent outlet can be used to monitor the amount of solvent discharged from the material, thereby monitoring the discharge rate of the solvent in the material.

[0021] In a specific possible implementation manner, the solvent injection unit and the solvent derivation unit are both provided in plurality, and the plurality of solvent injection units and the solvent derivation units are arranged in groups and at intervals in the axial direction of the extrusion cylinder.

[0022] By adopting the above technical scheme, using multiple groups of solvent injection units and solvent outlet units spaced at different axial positions of the extruder barrel, the solvent can be injected into and outlet into the material multiple times, and the high-boiling point impurity particles in the material can be removed in stages multiple times, which greatly improves the removal amount and removal rate of high-boiling point impurity particles in the material, and greatly improves the removal effect of high-boiling point impurity particles in the material.

[0023] The method for removing high boiling point impurity particles provided in this application adopts the following technical solution:

[0024] A method for removing high-boiling-point impurity particles uses an extrusion device capable of removing high-boiling-point impurity particles provided by the present application to remove high-boiling-point impurity particles, comprising the following steps: heating a material into a molten state and pushing the material toward a discharge end of an extrusion barrel; pressurizing a solvent to ensure that the solvent can remain in a liquid state at the heating temperature of the material; injecting the solvent into the material to allow the solvent to be fully mixed with the material; and discharging the solvent while preventing the material from flowing out to remove the high-boiling-point impurity particles dissolved in the solvent.

[0025] By adopting the above technical scheme, a method of injecting a solvent into a molten material under high pressure conditions is used, so that the solvent can be kept in a liquid state under a high temperature environment that keeps the material in a molten state, and the high-boiling-point impurity particles are dissolved by the liquid solvent, so that the high-boiling-point impurity particles are carried in the solvent and discharged, thereby removing the high-boiling-point impurity particles in the material; a method of mixing the molten material with the liquid solvent can be used to form a sufficient mixture between the material and the solvent, forming an opportunity for the high-boiling-point impurity particles mixed in different positions in the material to directly contact the solvent, so that the high-boiling-point impurity particles in the material can be quickly and fully dissolved in the solvent, thereby improving the removal effect and removal efficiency of the impurity particles.

[0026] In a specific embodiment, before injecting the solvent into the material, the method further comprises the step of heating the solvent so that the temperature of the solvent is higher than the melting point of the material.

[0027] By adopting the above technical solution, by heating the solvent to a temperature higher than the melting point of the material, it is possible to reduce the rapid drop in the temperature of the material caused by the solvent injected into the material absorbing a large amount of heat from the material, causing the nearby material to solidify due to the low temperature, affecting the fluidity of the material, and further affecting the removal effect of high-boiling point impurity particles in the material, as well as the plasticization effect of the material, thereby ensuring that the material plasticization extrusion and impurity particle removal are carried out simultaneously.

[0028] In summary, the present application includes at least one of the following beneficial technical effects:

[0029] 1. By arranging a solvent injection unit and a solvent extraction unit on the extruder, the solvent can be injected into the material in a molten state, so that the material is mixed with the solvent in a molten state, so that the impurity particles mixed in the material are more likely to contact with the solvent, which is conducive to the impurity particles being fully and quickly dissolved in the solvent. When the solvent extraction unit is used for removal, the impurity particles are removed from the material while the material is plasticized and extruded, which simplifies the removal process of the impurity particles and improves the removal effect and efficiency of the impurity particles;

[0030] 2. The solvent filling pump and pressure vessel can form a high-pressure state of the solvent, increase the boiling point of the solvent, and thus ensure that the solvent can remain in liquid state at a temperature that keeps the material in a molten state. The liquid solvent is used to dissolve and absorb high-boiling-point impurity particles in the material, thereby improving the solvent's solubility and loading capacity for impurity particles, and ensuring the removal speed and removal effect of impurity particles;

[0031] 3. The reverse driving screw arranged in the solvent outlet chamber can push the molten material toward the extruder barrel, preventing the high-viscosity material from flowing out through the solvent outlet under the high pressure in the extruder barrel, and at the same time allowing the low-viscosity solution to flow out along the gap between the reverse driving screw and the side wall of the inner cavity of the solvent outlet chamber, separating the solvent from the molten material during the material plasticizing and extrusion process, and conveniently removing high-boiling point impurity particles from the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic structural diagram of an embodiment of an extrusion device capable of removing high-boiling-point impurity particles of the present application.

[0033] Figure 2 It is a cross-sectional schematic diagram of a solvent derivation unit in one direction in one embodiment of the extrusion device capable of removing high-boiling-point impurity particles of the present application.

[0034] Figure 3 It is a cross-sectional schematic diagram of another direction of the solvent derivation unit in one embodiment of the extrusion device capable of removing high-boiling-point impurity particles of the present application.

[0035] Figure 4 The flowchart is a flowchart of an embodiment of the method for removing high boiling point impurity particles of the present application.

[0036] Explanation of the reference numerals: 1. extrusion barrel; 11. solvent injection port; 12. solvent outlet port; 2. extrusion screw; 3. screw drive unit; 4. material heating unit; 5. solvent injection unit; 51. solvent filling pump; 52. pressure vessel; 53. solvent heating mechanism; 54. flow control mechanism; 6. solvent outlet unit; 61. solvent outlet chamber; 611. solvent outlet port; 612. outlet heating device; 62. reverse push screw; 63. reverse screw drive mechanism; 64. transmission chamber; 641. transmission screw; 65. adjustment chamber; 651. spline sleeve; 652. screw mounting seat; 66. hydraulic valve; 67. solvent collecting container; 7. feeding device; 8. pelletizing device. DETAILED DESCRIPTION

[0037] The specific implementation of the present application is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present application, and is not used to limit the present application.

[0038] In the present application, unless otherwise stated, the directions or positional relationships indicated by the directional words such as "front" and "rear" are directions or positional relationships based on the material flow direction in the extrusion device capable of removing high-boiling-point impurity particles of the present application. Among them, the directional word "front" refers to the feeding direction, and the description of the directions or positional relationships of the various components in the extrusion device capable of removing high-boiling-point impurity particles of the present application is consistent with the description of the extrusion device.

[0039] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0040] An embodiment of the extrusion device of the present application that can remove high boiling point impurity particles is as follows: Figures 1 to 3 As shown, it includes an extrusion barrel 1, an extrusion screw 2, a screw driving unit 3 and a material heating unit 4. A feed port is arranged on the side of one end of the extrusion barrel 1, and a discharge port is arranged on the end face of the other end. The plastic material enters the feed port of the extrusion barrel 1 under the push of the feeding device 7, and is heated into a molten state in the extrusion barrel 1 and pushed toward the discharge end, extruded through the extrusion template arranged at the discharge port, and evenly cut by the pelletizing device 8 arranged at the rear end of the extrusion template to form granular plastic particles.

[0041] The extrusion screw 2 is arranged in the extrusion barrel 1 and along the axial direction of the extrusion barrel 1, and is used to push the molten plastic material from the feed end to the discharge end, and repeatedly shear and plasticize the plastic material during the pushing process to improve the performance of the plastic material.

[0042] The screw drive unit 3 is arranged at the feed end of the extruder barrel 1, and usually includes a screw drive motor, a clutch, and a reduction gearbox. The screw drive motor is connected to the reduction gearbox through the clutch, and is connected to the extrusion screw 2 through the reduction gearbox. When the screw drive motor is working, it can drive the extrusion screw 2 to rotate, forming a driving force to push the plastic material forward and shear and plasticize the plastic material.

[0043] The material heating unit 4 can be arranged on the side wall of the extrusion barrel 1 or inside the side wall to directly heat the side wall of the extrusion barrel 1; it can also be arranged outside the extrusion barrel 1 and connected to the heat exchange pipe arranged inside the side wall of the extrusion barrel 1 through a pipe, and the heat exchange pipe is used to heat the extrusion barrel 1, so that the material in the extrusion barrel 1 is heated into a molten state and maintained at a set temperature for shearing and plasticization.

[0044] A solvent injection unit 5 and a solvent extraction unit 6 are provided on the side wall of the extrusion barrel 1. The solvent injection unit 5 is provided at an axial position on the extrusion barrel 1 close to the feed port, and is used to pressurize and inject a solvent capable of dissolving the specified high-boiling-point impurity particles in the plastic material into the extrusion barrel 1. If it is necessary to remove the sodium chloride impurity particles mixed in the plastic material, pure water can be pressurized and injected into the extrusion barrel 1 through the solvent injection unit 5. The specific pressure of the solvent injected into the extrusion barrel 1 is determined by the set temperature of the molten plastic material in the section and the boiling point of the solvent, so as to ensure that the solvent remains in a liquid state at the set temperature. For example, if the set temperature of polyethylene (PE) plastic in a certain section is 120°C, the pressure of the water injected into the section needs to be set to above 205KPa.

[0045] Under the extrusion and shearing action of the extrusion screw 2, the molten plastic material and the liquid solvent are fully mixed, so that the high-boiling point impurity particles contained in the plastic material are fully in contact with the liquid solvent. At the same time, the liquid solvent is more conducive to the dissolution and dispersion of the high-boiling point impurity particles, so that the high-boiling point impurity particles are carried between the solvent molecules and flow with the solvent molecules.

[0046] The solvent derivation unit 6 is disposed on the extrusion barrel 1 and is located at a certain distance behind the solvent injection unit 5. The solvent derivation unit 6 can separate the plastic material and the solvent from the plastic material mixed with the solvent in the extrusion barrel 1, and guide the solvent out of the extrusion barrel 1, thereby separating the high boiling point impurity particles dissolved in the solvent and removing them from the plastic material.

[0047] The extrusion device capable of removing high-boiling-point impurity particles of the present application can remove high-boiling-point impurity particles mixed in the plastic material from the plastic material while plasticizing and extruding the plastic material, without the need to set up an independent high-boiling-point impurity removal process, thereby simplifying the high-boiling-point impurity particle removal process and improving the removal efficiency of high-boiling-point impurity particles. Moreover, compared with the traditional method of first cutting the plastic material into very thin slices and then soaking the slices in a solvent to dissolve the high-boiling-point impurity particles, the impurity particles are more likely to contact the solvent, dissolve in the solvent at a higher speed and dissolve in the solvent at a higher rate, and have a better high-boiling-point impurity particle removal effect.

[0048] In some embodiments of the extrusion device of the present application that can remove high boiling point impurity particles, such as Figure 1 As shown, a solvent injection port 11 connected to the barrel cavity is provided on the side wall of the extrusion barrel 1. The solvent injection unit 5 includes a solvent filling pump 51, a pressure container 52 and a solvent heating mechanism 53. The solvent filling pump 51 uses a pressure pump capable of generating sufficient pressure, and the solvent filling pump 51 is arranged between the container containing the solvent and the pressure container 52, and is used to transport the solvent into the pressure container 52 and form a set pressure in the pressure container 52.

[0049] The solvent heating mechanism 53 can be arranged in the pressure vessel 52, or can be arranged outside the pressure vessel 52, and is connected to the pressure vessel 52 through a pipeline, and is used to heat the solvent in the pressure vessel 52, or circulate and heat the solvent in the pressure vessel 52, so as to heat the solvent in the pressure vessel 52 to a temperature close to that of the molten plastic material in the extrusion barrel 1, so as to prevent the injection of the solvent into the extrusion barrel 1 from causing a significant change in the temperature of the plastic material in the extrusion barrel 1.

[0050] The pressure container 52 is connected to the solvent injection port 11, and the high-pressure solvent in the pressure container 52 can be injected into the extrusion barrel 1 through the solvent injection port 11, and the pressure in the extrusion barrel 1 is maintained at the same level as the pressure in the pressure container 52, so that the solvent remains in a liquid state in the extrusion barrel 1. Under the extrusion and shearing action of the extrusion screw 2, the plastic material in the extrusion barrel 1 is fully mixed with the liquid solvent, so that the high-boiling point impurity particles contained in the plastic material are more likely to contact with the liquid solvent, so that they can be better dissolved in the solvent.

[0051] In a preferred embodiment of the extrusion device of the present application that can remove high boiling point impurity particles, as Figure 1 As mentioned above, a flow control mechanism 54 is also provided in the solvent injection unit 5. The flow control mechanism 54 can use various mechanisms capable of controlling the flow of liquid, such as a flow pump, a flow valve, etc. The flow control mechanism 54 is provided at the connection between the pressure vessel 52 and the solvent injection port 11, and can control the flow of the solvent injected into the extrusion barrel 1 according to the actual content of high-boiling-point impurity particles in the plastic material and the content requirements of the high-boiling-point impurity particles of the product, while ensuring the removal effect of the high-boiling-point impurity particles, reducing the influence of the injected solvent on the plasticizing effect of the plastic material, and reducing the residual solvent components in the plastic material.

[0052] In some embodiments of the extrusion device of the present application that can remove high boiling point impurity particles, such as Figures 1 to 3 As shown, a solvent outlet 12 is provided on the side wall of the extrusion barrel 1 behind the solvent injection port 11. Usually, the solvent outlet 12 needs to maintain a sufficient distance from the solvent injection port 11 to ensure that the high-boiling point impurity particles of the plastic material can be fully dissolved in the solvent during the time when the plastic material is pushed from the solvent injection port 11 to the solvent outlet 12.

[0053] The solvent outlet unit 6 comprises a solvent outlet chamber 61, a reverse driving screw 62 and a reverse screw driving mechanism 63. One end of the solvent outlet chamber 61 is connected to the solvent outlet 12, and is usually arranged perpendicular to the extrusion barrel 1. Two reverse driving screws 62 are usually arranged, and the two reverse driving screws are arranged in parallel in the solvent outlet chamber 61. The reverse driving screws 62 are provided with reverse rotating spirals, and the spirals of the two reverse driving screws 62 are nested with each other. When the reverse driving screws 62 rotate, the mutually nested spirals can push the plastic material toward the solvent outlet 12. The reverse screw driving mechanism 63 usually uses an electric motor, and the reverse screw driving mechanism 63 is arranged at the end of the solvent outlet chamber 61, connected to the reverse driving screw 62, and is used to drive the reverse driving screw 62 to rotate. A solvent outlet 611 is arranged at one end of the solvent outlet chamber 61 away from the extrusion barrel 1, and the solvent outlet 611 is used to discharge the solvent separated from the plastic material and dissolved with high boiling point impurity particles.

[0054] When the plastic material mixed with the solvent moves to the position of the solvent outlet 12 under the push of the extrusion screw 2, the molten plastic material enters the solvent outlet chamber 61 under the action of the internal pressure of the extrusion barrel 1 and flows toward the solvent outlet 611. The rotation of the reverse driving screw 62 pushes the plastic material back into the extrusion barrel 1, so that the plastic material repeatedly flows in the extrusion barrel 1 and the solvent outlet chamber 61. Since the viscosity of the molten plastic material is high and the viscosity of the solvent is low, the plastic material is more likely to flow back toward the extrusion barrel 1 under the push of the reverse driving screw 62, and the reverse driving screw 62 has a smaller pushing effect on the solvent, so that the solvent is more likely to flow and gather along the gap between the reverse driving screw 62 and the gap between the reverse driving screw 62 and the solvent outlet chamber 61 toward the solvent outlet 611, and finally discharged through the solvent outlet 611. The solvent containing high-boiling-point impurity particles discharged through the solvent outlet 611 is collected into the solvent collection container 67 through a pipeline for extracting high-boiling-point impurity materials, or discharged after treatment.

[0055] As a specific embodiment of the extrusion device for removing high boiling point impurity particles of the present application, Figure 2 and Figure 3 As shown, a decoupling heating device 612 is also provided on the side wall of the solvent decoupling chamber 61. The decoupling heating device 612 is arranged on the solvent decoupling chamber 61 near the extrusion barrel 1, and is used to continue heating the plastic material leaving the extrusion barrel 1 to prevent the plastic material from cooling and solidifying after leaving the extrusion barrel 1, thereby affecting the pushing of the plastic material and the separation of the solvent from the plastic material.

[0056] In some embodiments of the extrusion device of the present application that can remove high boiling point impurity particles, such as Figure 2 and Figure 3As shown, a transmission chamber 64 and an adjustment chamber 65 are provided between the solvent outlet chamber 61 and the reverse screw drive mechanism 63. Two transmission screws 641 are provided in the transmission chamber 64, and the two transmission screws 641 are provided in parallel with each other and are both rotatably connected to the transmission chamber 64 through bearings. The reverse screw drive mechanism 63 is fixed on the transmission chamber 64, and the output shaft of the reverse screw drive mechanism 63 extends into the transmission chamber 64, and a drive mechanism gear is provided on the output shaft, and transmission screw gears are provided at different positions on the two transmission screws 641, and the transmission screw gears on the two transmission screws 641 are meshed with the drive mechanism gears, and when the reverse screw drive mechanism 63 rotates, the two transmission screws 641 can be driven to rotate synchronously.

[0057] The regulating chamber 65 is fixed between the solvent outlet chamber 61 and the transmission chamber 64, and two spline sleeves 651 and a screw mounting seat 652 are arranged in the regulating chamber 65. The screw mounting seat 652 is fixed in the regulating chamber 65, and two spline sleeve support holes are arranged on the end plate connected to the solvent outlet chamber 61. The two spline sleeves 651 are respectively arranged in the two spline sleeve support holes on the screw mounting seat 652. The rotating shaft at one end of the reverse driving screw 62 is rotatably connected with the end plate of the regulating chamber 65 through a bearing, and the ends of the two reverse driving screws 62 are both extended into the screw mounting seat 652, and are respectively spline-connected with one end of a spline sleeve 651. The ends of the two transmission screws 641 close to the regulating chamber 65 are both extended into the regulating chamber 65, and are respectively spline-connected with the other end of a spline sleeve 651.

[0058] In this way, the two synchronously rotating transmission screws 641 transmit the rotational driving force to a reverse pushing screw 62 through a spline sleeve 651, respectively, driving the two reverse pushing screws 62 to rotate synchronously in the solvent outlet chamber 61, and play a reverse pushing role on the plastic material. The rotational driving force transmitted through the spline sleeve 651 can improve the freedom of movement of the two reverse pushing screws 62 and prevent the reverse pushing screws 62 from getting stuck during the rotation process.

[0059] In some embodiments of the extrusion device of the present application that can remove high boiling point impurity particles, such as Figure 1 As shown, a hydraulic valve 66 is provided between the solvent outlet unit 6 and the solvent outlet 12 , and the hydraulic valve 66 can monitor the pressure of the plastic material at the solvent outlet 12 , and maintain the stability of the pressure of the plastic material in the extrusion barrel 1 by controlling the rotation speed of the reverse driving screw 62 .

[0060] A pressure gauge is provided at the solvent discharge port 611, through which the amount of solvent separated from the plastic material can be monitored, thereby controlling the working parameters of the solvent injection unit 5 and the solvent extraction unit 6 to ensure the removal effect of high-boiling point impurity particles in the plastic material.

[0061] In some embodiments of the extrusion device of the present application that can remove high boiling point impurity particles, such as Figure 1 As shown, multiple groups of solvent injection units 5 and solvent derivation units 6 are arranged in pairs on the side wall of the extrusion cylinder 1, and each group of solvent injection units 5 and solvent derivation units 6 are respectively arranged at different positions in the axial direction of the extrusion cylinder 1, and are arranged at intervals in the axial direction of the extrusion cylinder 1. Among them, each group of solvent derivation units 6 is arranged behind the same group of solvent injection units 5, and the solvent injection units 5 arranged in the rear group are located behind the solvent derivation units 6 in the front group.

[0062] The arrangement of each group of solvent injection unit 5 and solvent extraction unit 6 can perform multiple rounds of extraction and separation of high-boiling-point impurity particles mixed in the plastic material during the plasticization process of the plastic material, thereby being able to separate the high-boiling-point impurity particles in the plastic material to a greater extent with a smaller amount of solvent injection, thereby improving the removal efficiency of the high-boiling-point impurity particles.

[0063] The extrusion device capable of removing high-boiling-point impurity particles of the present application can be used to implement the high-boiling-point impurity particle removal method of the present application, and can conveniently and efficiently remove high-boiling-point impurity particles mixed in the plastic material during the plasticizing and extrusion process of the plastic material.

[0064] An embodiment of the method for removing high boiling point impurity particles of the present application can utilize the extrusion device capable of removing high boiling point impurity particles of any embodiment of the present application to remove high boiling point impurity particles, such as Figure 4 As shown, the following steps are included:

[0065] 1. The material is heated into a molten state and pushed toward the discharge end of the extrusion barrel 1 under the action of the extrusion screw 2.

[0066] The plastic material in the extrusion barrel 1 is melted into a molten state under the heating of the material heating unit 4, and the extrusion screw 2 is driven by the screw driving unit 3 to rotate, pushing the molten plastic material to the discharge end of the extrusion barrel 1, and in the process of pushing, the plastic material is sheared and plasticized to improve the quality of the plastic material. The plastic material pushed to the discharge end of the extrusion barrel 1 is extruded through the extrusion template and cut into plastic particles under the action of the pelletizing device.

[0067] 2. Pressurize the solvent used to dissolve the high-boiling point impurity particles in the plastic material to a level that allows the solvent to remain in a liquid state at the heating temperature of the molten plastic material.

[0068] Since the molten plastic material usually has a high temperature, the solvent used to dissolve the high-boiling impurity particles usually boils at the melting temperature of the plastic material to form a gaseous state. The gaseous solvent molecules cannot dissolve and absorb the high-boiling impurity particles, and cannot separate the impurity particles from the plastic material. The melting point of plastic materials is usually above 100°C. For example, the melting point of PE plastic is usually 110-130°C, and the boiling point of water commonly used to dissolve the sodium chloride particles mixed in PE is 100°C under normal pressure. At the melting temperature of PE plastic, water has been vaporized into water vapor and has lost its ability to dissolve sodium chloride, making it impossible to separate the sodium chloride particles from the PE plastic. Pressurizing water to about 205KPa can increase the boiling point of water to 120°C, so that the water remains in a liquid state at a temperature below 120°C, so that the sodium chloride particles mixed in PE can be dissolved and separated in the molten state of PE. Pressurizing to a higher pressure can further increase the boiling point of water, allowing water to remain liquid at higher temperatures and maintain the ability to dissolve and absorb sodium chloride particles at higher temperatures.

[0069] 3. Inject the solvent into the material so that the solvent and the material are fully mixed.

[0070] The solvent in a high-pressure state is injected into the extrusion barrel 1 through the solvent injection unit 5, and the high-pressure state is maintained in the extrusion barrel 1, so that the molten plastic material and the liquid solvent are fully mixed under the shearing action of the extrusion screw 2. In this way, the high-boiling point impurity particles mixed in the molten plastic material are more likely to contact with the liquid solvent, so as to be dissolved in the solvent and separated from the plastic material.

[0071] 4. While preventing the material from flowing out, discharge the solvent to remove the high-boiling point impurity particles dissolved in the solvent.

[0072] A solvent outlet 12 on the extrusion barrel 1 is provided with a solvent outlet unit 6 to prevent the molten plastic material in a high-pressure state from flowing out through the solvent outlet 12. Since the viscosity of the solvent is relatively small, the solvent outlet unit 6 has a smaller blocking effect on the outflow of the solvent, making it easier for the solvent to flow out through the solvent outlet 12. After the solvent flows out of the extrusion barrel 1, the high-boiling-point impurity particles dissolved in the solvent are taken out, and the high-boiling-point impurity particles are removed from the plastic material. In this way, while the plastic material is extruded and plasticized, the high-boiling-point impurity particles in the plastic material can be effectively removed by utilizing the good solubility of the solvent for the high-boiling-point impurity particles, thereby simplifying the removal process of the high-boiling-point impurity particles and improving the removal effect and efficiency of the high-boiling-point impurity particles.

[0073] In a preferred embodiment of the high-boiling-point impurity particle removal method of the present application, before injecting the solvent into the plastic material in the extrusion barrel 1, the solvent is also heated by the solvent heating mechanism 53 to a temperature higher than the melting point of the plastic material and close to the temperature of the molten plastic material in the extrusion barrel 1. In this way, when the solvent is injected into the plastic material, the change in the temperature of the plastic material caused by contact with the solvent can be reduced, especially the solidification of the plastic material due to a rapid drop in temperature is avoided, and the change in the fluidity of the plastic material due to a drop in temperature is reduced. While removing the high-boiling-point impurity particles in the plastic material, the influence on the advancement and plasticization of the plastic material is reduced, and the pelletizing effect of the plastic material is guaranteed.

[0074] In the description of the present application, the description with reference to the terms "one embodiment", "specific embodiment", "preferred embodiment", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0075] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. An extrusion device capable of removing high-boiling-point impurity particles, comprising an extrusion barrel (1), an extrusion screw (2), a screw drive unit (3) and a material heating unit (4), wherein the extrusion screw (2) is arranged in the extrusion barrel (1) so as to be able to push the material from a feed port at one side to a discharge port at the other end under the drive of the screw drive unit (3), and the material heating unit (4) is arranged on the extrusion barrel (1) so as to be able to heat the material in the extrusion barrel (1) into a molten state, characterized in that: The extrusion barrel (1) is provided with a solvent injection unit (5) and a solvent extraction unit (6); the solvent injection unit (5) is capable of pressurizing and injecting a solvent for dissolving high-boiling-point impurity particles into the extrusion barrel (1) so that the solvent remains in a liquid state in the extrusion barrel (1); the solvent extraction unit (6) is arranged behind the solvent injection unit (5) and is capable of extracting the solvent mixed in the material from the extrusion barrel (1); The extruder barrel (1) comprises a solvent outlet (12), and the solvent outlet unit (6) comprises a solvent outlet chamber (61), a reverse driving screw (62) and a reverse screw driving mechanism (63). One end of the solvent outlet chamber (61) is connected to the solvent outlet (12), the reverse driving screw (62) is arranged in the solvent outlet chamber (61) and can push the material to move in the direction of the solvent outlet (12) under the reverse screw driving mechanism (63), and the other end of the solvent outlet chamber (61) is provided with a solvent discharge outlet (611).

2. The extrusion device capable of removing high boiling point impurity particles according to claim 1, characterized in that: The extrusion barrel (1) is provided with a solvent injection port (11), and the solvent injection unit (5) comprises a solvent filling pump (51), a pressure container (52) and a solvent heating mechanism (53). The solvent filling pump (51) is connected to the pressure container (52) and can inject a solvent of a set pressure into the pressure container (52). The solvent heating mechanism (53) is arranged in the pressure container (52) so as to heat the solvent in the pressure container (52). The pressure container (52) is connected to the solvent injection port (11) so as to inject the solvent into the extrusion barrel (1) through the solvent injection port (11).

3. The extrusion device capable of removing high boiling point impurity particles according to claim 2, characterized in that: The solvent injection unit (5) further comprises a flow control mechanism (54), wherein the flow control mechanism (54) is arranged at the connection between the pressure container (52) and the solvent injection port (11) so as to control the flow rate of the solvent injected into the extrusion barrel (1).

4. The extrusion device capable of removing high boiling point impurity particles according to claim 1, characterized in that: A solvent outlet heating device (612) is provided on a side wall of the solvent outlet chamber (61) adjacent to one end of the extrusion cylinder (1).

5. The extrusion device capable of removing high boiling point impurity particles according to claim 1, characterized in that: A transmission chamber (64) and an adjustment chamber (65) are provided between the solvent outlet chamber (61) and the reverse screw drive mechanism (63); a transmission screw (641) is provided in the transmission chamber (64); an output shaft of the reverse screw drive mechanism (63) extends into the transmission chamber (64) and is drivingly connected to the transmission screw (641) via a gear; a spline sleeve (651) and a screw mounting seat (652) are provided in the adjustment chamber (65); the screw mounting seat (652) is fixed in the adjustment chamber (65), the spline sleeve (651) is supported on the screw mounting seat (652), the rotating shaft of the reverse push screw (62) is rotatably connected to the adjustment chamber (65), and the end thereof extends into the screw mounting seat (652) and is spline-connected to one end of the spline sleeve (651), and one end of the transmission screw (641) extends into the adjustment chamber (65) and is spline-connected to the other end of the spline sleeve (651).

6. The extrusion device capable of removing high boiling point impurity particles according to claim 5, characterized in that: A hydraulic valve (66) is provided between the solvent outlet unit (6) and the solvent outlet (12), and a pressure gauge is provided at the solvent outlet (611).

7. The extrusion device capable of removing high boiling point impurity particles according to any one of claims 1 to 6, characterized in that: The solvent injection unit (5) and the solvent derivation unit (6) are both provided in plurality, and the plurality of solvent injection units (5) and solvent derivation units (6) are arranged in groups and at intervals in the axial direction of the extrusion cylinder (1).

8. A method for removing high boiling point impurity particles, characterized in that: Removing high-boiling-point impurity particles using an extrusion device capable of removing high-boiling-point impurity particles according to any one of claims 1 to 7 comprises the following steps: The material is heated into a molten state and pushed toward the discharge end of the extruder (1); Pressurizing the solvent to ensure that the solvent can remain liquid at the heating temperature of the material; Injecting the solvent into the material so that the solvent and the material are fully mixed; While preventing the material from flowing out, the solvent is discharged to remove high-boiling-point impurity particles dissolved in the solvent.

9. The method according to claim 8, characterized in that Before injecting the solvent into the material, the method further comprises the step of heating the solvent so that the temperature of the solvent is higher than the melting point of the material.

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