Three-stage extrusion device for tandem polymer foaming extrusion processing

Abstract

The present invention relates to a three - stage extrusion device for serial polymer foaming extrusion processing, which includes a first - stage extruder for heating and plasticizing raw materials. A raw material feeder is provided on the first - stage extruder. The discharge end of the first - stage extruder is connected to a second - stage extruder for adding additives to the raw materials, and an additive feeder is provided on the second - stage extruder; the output end of the second - stage extruder is connected to a third - stage extruder for cooling and homogenizing the raw materials. The first - stage extruder, the second - stage extruder and the third - stage extruder are connected in sequence. The second - stage extruder can be specifically used for mixing raw materials and additives, which can ensure the mixing effect between raw materials and additives to the greatest extent, ensure that the additives can be evenly mixed in the raw materials, thereby guaranteeing product quality. The rotational speeds and the length - to - diameter ratios of the three extruders can be freely adjusted. According to the current raw materials and process requirements, the most suitable rotational speed and extruder parameters for the current stage can be selected, so that the processing effect of each step can reach the best.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer foaming extrusion equipment, and in particular to a three-stage extrusion device for serial polymer foaming extrusion processing. Background Art

[0002] Currently, the manufacturing method of foamed products is as follows: carbon dioxide or inert gas is introduced into a polymer melt through conventional processing equipment such as extruders, injection molding machines, and molding presses to make them mix evenly. After pressure relief, the gas dissolved in the melt expands to obtain foamed products.

[0003] The utility model with the publication number CN209095860U provides a foaming extruder, which includes a barrel. The barrel includes a feeding section, an air inlet section, and an extrusion section connected in sequence. A screw is provided in the barrel. A driving device for driving the screw to rotate is connected to one side of the feeding section away from the air inlet section. During operation, raw materials enter the barrel from the feeding section, the raw materials are melted and extended in the barrel under the drive of the screw, the foaming agent enters the barrel from the air inlet section, and after the foaming agent and the raw materials are mixed in the barrel, they are extruded from the extrusion section to form foamed products.

[0004] However, in the screw extruder in the prior art, the melting of raw materials and the mixing of raw materials and the foaming agent are both completed in one barrel. Since the length of the barrel cannot be too long, the residence time of the raw materials in the barrel is limited, resulting in a poor mixing effect of the raw materials and the foaming agent. In this way, after foaming and molding, the distribution of pores in the raw materials is uneven, and the product quality cannot be effectively guaranteed. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a three-stage extrusion device for serial polymer foaming extrusion processing, in which the foaming agent and the raw materials are mixed evenly, and the product quality can be effectively guaranteed.

[0006] The above invention purpose of the present invention is achieved through the following technical solutions: A three-stage extrusion device for serial polymer foaming extrusion processing includes a first-stage extruder for heating and plasticizing raw materials. A raw material feeder is provided on the first-stage extruder. The discharge end of the first-stage extruder is connected to a second-stage extruder for adding additives to the raw materials. An additive feeder is provided on the second-stage extruder; the output end of the second-stage extruder is connected to a third-stage extruder for cooling and homogenizing the raw materials.

[0007] By adopting the above technical solution, the first-stage extruder, the second-stage extruder and the third-stage extruder are connected in sequence. The second-stage extruder can be specifically used for mixing raw materials and additives, which can ensure the mixing effect between the raw materials and additives to the greatest extent, ensure that the additives can be evenly mixed in the raw materials, and thus guarantee the product quality. The first-stage extruder, the second-stage extruder and the third-stage extruder can respectively process the raw materials in different steps. The rotation speeds and the length-diameter ratios of the three extruders can be freely adjusted. During production, according to the current raw materials and process requirements, the most suitable rotation speed and extruder parameters for the current stage can be selected, so that the processing effect of each step can reach the best, thereby effectively guaranteeing the product quality and production efficiency.

[0008] The present invention is further configured as: a polymer melt cooler is provided between the first-stage extruder and the second-stage extruder.

[0009] By adopting the above technical solution, the polymer melt cooler can cool the raw materials entering the second-stage extruder. After the raw materials are appropriately cooled, they enter the second-stage extruder. In this way, after the additives are added to the raw materials, the product performance can be effectively improved and the product quality can be guaranteed. In addition, the polymer melt cooler can be selected to be turned on or off according to needs. When it is not necessary to cool the raw materials, the polymer melt cooler can be turned off, improving the adaptability of the production process.

[0010] The present invention is further configured as: the discharge end of the third-stage extruder is connected with a static mixer, and the rear end of the static mixer is connected with a mold.

[0011] By adopting the above technical solution, the static mixer can not only stably realize the output of the raw materials, but also remix the products output from the third-stage extruder, further improving the mixing effect of the raw materials and additives. For different products, different models of molds can be replaced, with strong adaptability.

[0012] The present invention is further configured as: the length-diameter ratio of the first-stage extruder is 16:1 - 32:1, the length-diameter ratio of the second-stage extruder is 24:1 - 64:1, the length-diameter ratio of the third-stage extruder is 16:1 - 36:1, and the rotation speed of the second-stage extruder is lower than that of the first-stage extruder.

[0013] By adopting the above technical solution, the first-stage extruder is set to be shorter and has a large heating power, which can very quickly realize the melting and plasticizing of the raw materials. The rotation speed of the second-stage extruder is lower than that of the first-stage extruder, and the second-stage extruder is longer. In this way, the raw materials stay in the second-stage extruder for a longer time, and the mixing of the raw materials can be more fully and evenly realized. The third-stage extruder selects a single-screw extruder, and the length of the third-stage extruder is moderate, which can stably realize the output of the raw materials while ensuring the cooling efficiency of the raw materials.

[0014] The present invention is further configured as follows: the barrel of the three-stage extruder is composed of an inner barrel and an outer barrel sleeved with each other. A spiral cooling channel is provided on the outer peripheral surface of the inner barrel. Liquid inlet pipes and liquid outlet pipes are provided at both ends of the outer barrel. The liquid inlet pipes and the liquid outlet pipes are respectively communicated with both ends of the cooling channel. A heat exchanger and a cooling pump are connected in series between the liquid inlet pipe and the liquid outlet pipe. A liquid storage tank for storing a cooling medium is further included, and the cooling pump is placed in the liquid storage tank.

[0015] By adopting the above technical solution, the cooling pump transports the cooling medium in the liquid storage tank into the cooling channel. The cooling medium absorbs heat, thereby realizing the cooling of the raw materials. After the cooling medium is output from the liquid outlet pipe, it enters the heat exchanger. The heat exchanger cools the coolant output from the cooling channel. The heat exchanger is connected to the liquid storage tank. The cooled coolant output from the heat exchanger enters the liquid storage tank for reuse.

[0016] The present invention is further configured as follows: a cooling cover is provided outside the outer barrel. The cooling cover surrounds the outer barrel. An axial flow fan is provided on the cooling cover. An air inlet hole communicated with the air outlet of the axial flow fan is provided on the cooling cover. There are several axial flow fans, and several of the axial flow fans are arranged in an array along the length direction of the cooling cover on the cooling cover. A plurality of ventilation holes for the air flow to flow out are provided on the cooling cover.

[0017] By adopting the above technical solution, during operation, the axial flow fan and the ventilation holes cooperate to generate a stable air flow in the cooling cover. When the air flow is flowing, it can take away the heat on the surface of the outer barrel and cool the outer barrel. The external cooling system can assist the internal cooling system to cool the outer barrel. In this way, the load of the internal cooling system will be reduced, and the temperature of the cooling medium output from the liquid outlet pipe can be effectively reduced. This not only reduces the volume of the heat exchanger, but also can reduce the load of the cooling pump, extend the service life of the cooling pump, and reduce energy consumption.

[0018] The present invention is further configured as follows: the vertical section of the cooling cover is in the shape of a regular octagon. The axial flow fans are arranged in two columns and symmetrically arranged on both sides of the cooling cover. The ventilation holes are provided on the top surface and the bottom surface of the cooling cover. The cooling cover is composed of a left cover body and a right cover body arranged symmetrically. The left cover body and the right cover body are symmetrically arranged with respect to the length direction of the barrel. The left cover body and the right cover body are fixedly connected by a buckle.

[0019] By adopting the above technical solution, the two columns of axial flow fans are symmetrically arranged on both sides of the cooling cover, and the ventilation holes are provided on the top surface and the bottom surface of the cooling cover. In this way, the air flow blown out by the axial flow fans can be discharged from the top surface and the bottom surface of the cooling cover, and the hot air flow in the cooling cover can be stably discharged. When it is necessary to clean or replace the inside of the cooling cover, only need to open the buckle, and the left cover body and the right cover body can be separated, so as to disassemble the cooling cover.

[0020] The present invention is further configured as follows: A plurality of rollers are circumferentially arrayed around the outer circumference of the outer cylinder at both ends of the cooling cover. The rotation axes of the rollers are arranged parallel to the axis of the outer cylinder. Convex rings are provided on the outer peripheral surface of the outer cylinder at both ends of the cooling cover. Annular grooves that cooperate with the convex rings are provided at both ends of the cooling cover. Conductive rings connected to a power source are provided on the side surfaces of the convex rings. Conductive sheets that contact the conductive rings are provided on the annular grooves. The axial flow fan is electrically connected to the conductive sheets; A drive system for driving the cooling cover to rotate is further included.

[0021] By adopting the above technical solution, by providing rollers, the cooling cover can rotate relative to the outer cylinder, so that the axial flow fan can cool the outer cylinder in all directions, further improving the cooling effect of the axial flow fan. The drive system can drive the cooling cover to rotate, improving the stability of the heat dissipation process. After installation, the conductive sheet can contact the conductive ring, thus stably realizing the power supply of the axial flow fan. And the conductive sheet is arranged in the annular groove, and the annular groove can shield and protect the conductive sheet, improving the safety during use.

[0022] The present invention is further configured as follows: The drive system includes gear teeth provided on the outer peripheral surface of the convex ring. The gear teeth are circumferentially arrayed on the convex ring. A gear that meshes with the gear teeth is rotatably connected to the cooling cover. A driving member for driving the gear to rotate is provided on the cooling cover.

[0023] By adopting the above technical solution, during operation, the driving member drives the gear to rotate. Since the gear meshes with the gear teeth and the convex ring is fixed, the cooling cover can be driven to rotate, with a simple structure and convenient operation.

[0024] The present invention is further configured as follows: Connecting rings arranged in a ring shape are provided around the convex ring at both ends of the cooling cover. The annular grooves are provided on the inner surface of the connecting rings. Positioning pins are slidably connected to the side surfaces of the connecting rings along the axis direction of the outer cylinder. Positioning holes that cooperate with the positioning pins are provided on the convex ring.

[0025] By adopting the above technical solution, when the cooling cover does not need to rotate, the driving member is turned off, and the positioning pins are inserted into the positioning holes, so that the rotation of the cooling cover can be restricted, and the cooling cover is fixed on the outer cylinder.

[0026] In summary, the present invention includes at least one of the following beneficial technical effects:

[0027] 1. By adopting the three-stage extrusion method, the second-stage extruder can be specifically used for mixing raw materials and additives, which can ensure the mixing effect between the raw materials and additives to the greatest extent. Moreover, the mixing temperature and rotation speed of the second-stage extruder can be adjusted, which can adapt to the addition and mixing of more additives;

[0028] 2. The barrel of the three - stage extruder is cooled by combining two methods: using a cooling medium and an axial - flow fan, which can effectively improve the cooling effect. Brief Description of the Drawings

[0029] Figure 1 It is a schematic diagram of the overall structure of the first embodiment of the present invention.

[0030] Figure 2 It is a schematic diagram of the installation of the cooling cover and the outer cylinder in the second embodiment of the present invention.

[0031] Figure 3 It is Figure 2 the assembly explosion diagram (the inner cylinder is separated from the outer cylinder).

[0032] Figure 4 It is Figure 2 the vertical sectional view in

[0033] Figure 5 It is Figure 4 the enlarged view of part A in

[0034] Figure 6 It is a schematic diagram of the convex - ring structure of the present invention.

[0035] Figure 7 It is a schematic diagram of the installation of the wind wheel in the third embodiment of the present invention.

[0036] In the figure, 1 is the first - stage extruder; 11 is the raw - material feeder; 12 is the polymer melt cooler; 2 is the second - stage extruder; 21 is the additive feeder; 3 is the third - stage extruder; 31 is the static mixer; 32 is the die; 4 is the inner cylinder; 41 is the cooling channel; 5 is the outer cylinder; 51 is the liquid inlet pipe; 52 is the liquid outlet pipe; 53 is the annular convex rib; 6 is the cooling cover; 61 is the left cover body; 611 is the positioning groove; 62 is the right cover body; 621 is the positioning block; 63 is the buckle; 64 is the roller; 65 is the gear; 66 is the motor; 7 is the axial - flow fan; 71 is the air inlet hole; 72 is the ventilation hole; 8 is the convex ring; 81 is the conductive ring; 82 is the gear teeth; 83 is the positioning hole; 9 is the connecting ring; 91 is the annular groove; 92 is the conductive sheet; 93 is the positioning pin; 10 is the wind wheel; 101 is the wheel shaft; 102 is the wheel blade. Detailed Embodiments

[0037] The present invention will be further described in detail below with reference to the accompanying drawings.

[0038] Embodiment 1:

[0039] Refer to Figure 1, a three - stage extrusion device for serial polymer foaming extrusion processing disclosed by the present invention, includes a first - stage extruder 1. The discharge end of the first - stage extruder 1 is connected to a second - stage extruder 2, and the discharge end of the second - stage extruder 2 is connected to a third - stage extruder 3. A raw material feeder 11 is connected to the first - stage extruder 1. The raw material feeder 11 adds raw materials into the first - stage extruder 1. The raw materials are heated and plasticized in the first - stage extruder 1. After forming a molten state, they enter the second - stage extruder 2. A additive feeder 21 is connected to the second - stage extruder 2. The additive feeder 21 can feed additives into the second - stage extruder 2. The molten raw materials and additives are mixed in the second - stage extruder 2. After the mixing is completed, the raw materials enter the third - stage extruder 3, where they are cooled and homogenized, and finally the finished products are output from the third - stage extruder 3.

[0040] Refer to Figure 1 , the first - stage extruder 1, the second - stage extruder 2 and the third - stage extruder 3 are connected in sequence. The second - stage extruder 2 can be specifically used for mixing raw materials and additives, which can ensure the mixing effect between raw materials and additives to the greatest extent, ensure that the additives can be evenly mixed in the raw materials, and thus guarantee the product quality. The first - stage extruder 1, the second - stage extruder 2 and the third - stage extruder 3 can process raw materials in different steps respectively. The rotation speeds and the length - to - diameter ratios of the three extruders can be freely adjusted. During production, according to the current raw materials and process requirements, the most suitable rotation speed and extruder parameters for the current stage can be selected. For example, the rotation speed and temperature of the first - stage extruder 1 can be adjusted to a relatively high state, so that the heating and plasticization of raw materials can be achieved quickly, and the processing effect of each step can reach the best, thereby effectively guaranteeing the product quality and production efficiency.

[0041] Refer to Figure 1 , to meet the processing requirements of different additives, when encountering some additives that are not resistant to high temperatures, the temperature of the raw materials entering the second - stage extruder 2 cannot be too high, otherwise it is easy to affect the performance of the additives. Therefore, a polymer melt cooler 12 is provided between the first - stage extruder 1 and the second - stage extruder 2. The polymer melt cooler 12 can cool the raw materials entering the second - stage extruder 2. After the raw materials are appropriately cooled, they enter the second - stage extruder 2. In this way, after the additives are added to the raw materials, the product performance can be effectively improved and the product quality can be guaranteed. In addition, the polymer melt cooler 12 can be selected to be turned on or off according to needs. When the raw materials do not need to be cooled, the polymer cooler can be turned off to improve the adaptability of the production process.

[0042] Refer to Figure 1, to stably achieve the output of the product, a static mixer 31 is connected to the discharge end of the three - stage extruder 3, and a die 32 is connected to the discharge end of the static mixer 31. The static mixer 31 can not only stably achieve the output of the raw materials, but also remix the products output from the three - stage extruder 3, further improving the mixing effect of the raw materials and additives. After the raw materials are output from the static mixer 31, they can enter the die 32. The die 32 is designed according to the product requirements. After the raw materials are output from the die 32, the final product can be formed. For different products, different models of dies 32 can be replaced, with strong adaptability.

[0043] Refer to Figure 1 , to effectively ensure that the functions of each stage can be reliably realized, the length - to - diameter ratio of the first - stage extruder 1 is 16∶1 - 32∶1, and the first - stage extruder 1 is a twin - screw extruder. The first - stage extruder 1 is set shorter with a large heating power, which can very quickly achieve the melting and plasticizing of the raw materials. The length - to - diameter ratio of the second - stage extruder 2 is 24∶1 - 64∶1, and the second - stage extruder 2 is also a twin - screw extruder. The rotation speed of the second - stage extruder 2 is lower than that of the first - stage extruder 1. The second - stage extruder 2 is longer, so that the raw materials stay in the second - stage extruder 2 for a longer time, and the mixing of the raw materials can be more fully and evenly realized. The length - to - diameter ratio of the third - stage extruder 3 is 16∶1 - 36∶1, and the third - stage extruder 3 is a single - screw extruder. The length of the third - stage extruder 3 is moderate, and the output of the raw materials can be stably achieved while ensuring the cooling efficiency of the raw materials.

[0044] Adopting the technical solution of this application, the production range is very wide, and it can achieve PS foaming, XPS foaming, EPS foaming, PLA extrusion foaming, and PU foaming, etc. The additives can be blowing agents or other functional additives. The blowing agents can be carbon dioxide, nitrogen, alcohol, freon, alkanes, etc.

[0045] The implementation principle of this embodiment is as follows: During operation, the raw materials enter the first - stage extruder 1 through the raw material feeder 11. The raw materials are heated and plasticized in the first - stage extruder 1. After the molten raw materials pass through the polymer melt cooler 12, they enter the second - stage extruder 2. The additives enter the second - stage extruder 2 under the transportation of the additive feeder 21. The additives and the raw materials are mixed in the second - stage extruder 2. After mixing, the additives enter the third - stage extruder 3. The raw materials are cooled and homogenized in the third - stage extruder 3, and finally pass through the static mixer 31 and enter the die 32. After being output from the die 32, the finished product can be formed.

[0046] Embodiment Two:

[0047] A three - stage extrusion device for serial polymer foaming extrusion processing, refer to Figure 2 And Figure 3, different from the first embodiment, in this embodiment, the barrel of the triple extruder 3 is composed of an inner barrel 4 and an outer barrel 5. The outer diameter of the inner barrel 4 is equal to the inner diameter of the outer barrel 5. The cooling channel 41 includes a spiral groove provided on the outer surface of the inner barrel 4. Liquid inlet pipes 51 and liquid outlet pipes 52 are provided at both ends of the outer barrel 5. The liquid inlet pipes 51 and the liquid outlet pipes 52 communicate with both ends of the cooling channel 41 respectively. After the outer barrel 5 is sleeved outside the inner barrel 4, the cooling channel 41 can be formed. The liquid inlet pipe 51 is connected with a cooling pump. The cooling pump is arranged in a liquid storage tank. A cooling medium is stored in the liquid storage tank. The cooling medium is generally cooling oil. The cooling pump transports the cooling medium in the liquid storage tank into the cooling channel 41. The cooling medium is output from the liquid outlet pipe 52 and then enters a heat exchanger. The heat exchanger cools the cooling liquid output from the cooling channel 41. The heat exchanger is connected with the liquid storage tank. The cooled cooling liquid output from the heat exchanger enters the liquid storage tank to be reused.

[0048] Refer to Figure 2 and Figure 3 , to further improve the cooling effect of the outer barrel 5, a cooling cover 6 is provided outside the outer barrel 5. The cooling cover 6 is arranged around the outer barrel 5. An axial flow fan 7 is provided on the cooling cover 6. An air inlet hole 71 communicating with the air outlet of the axial flow fan 7 is provided on the cooling cover 6. The air inlet hole 71 and the air outlet direction of the axial flow fan 7 are both perpendicular to the axis of the outer barrel 5. To improve the air cooling effect, there are several axial flow fans 7. The several axial flow fans 7 are arranged in an array along the length direction of the cooling cover 6 on the cooling cover 6. Several ventilation holes 72 for air to flow out are provided on the cooling cover 6. When the axial flow fan 7 is turned on, the air blown by the axial flow fan 7 can blow onto the outer barrel 5 to cool the outer wall of the outer barrel 5. The air blown into the cooling cover 6 can be directly discharged through the ventilation holes 72. The axial flow fan 7 is convenient for maintenance and installation, and at the same time has low power consumption, which can effectively reduce energy consumption and save energy.

[0049] Refer to Figure 2 and Figure 3 , several annular ridges 53 are provided on the outer peripheral surface of the outer barrel 5. The annular ridges 53 are arranged in an array along the length direction of the barrel. The annular ridges 53 can increase the contact area between the barrel and the air. When the air flows through the surface of the barrel, more heat on the barrel can be taken away, further improving the cooling effect of the barrel. At the same time, by setting the annular ridges 53, the overall anti-bending performance of the barrel can also be increased, improving the structural strength of the barrel.

[0050] Refer to Figure 2 and Figure 3, for the convenience of installing and disassembling the axial flow fan 7, the vertical section of the cooling cover 6 is octagonal, that is, the cooling cover 6 is generally octagonal prism-shaped as a whole. The axial flow fans 7 are arranged in two rows, and the two rows of axial flow fans 7 are symmetrically arranged on both sides of the cooling cover 6. The ventilation holes 72 are arranged on the top surface and the bottom surface of the cooling cover 6. In this way, the air flow blown out by the axial flow fan 7 can be discharged from the top surface and the bottom surface of the cooling cover 6, and the hot air flow inside the cooling cover 6 can be stably discharged. In addition, two rows of ventilation holes 72 are arranged on both the top surface and the bottom surface of the cooling cover 6, further increasing the air discharge volume of the ventilation holes 72 and improving the air cooling efficiency.

[0051] Refer to Figure 2 and Figure 3 , for the convenience of installing and disassembling the cooling cover 6, the cooling cover 6 is composed of a left cover body 61 and a right cover body 62 which are symmetrically arranged. The left cover body 61 and the right cover body 62 are symmetrically arranged with respect to the length direction of the machine barrel. The left cover body 61 and the right cover body 62 are fixedly connected by buckles 63. There are several buckles 63, and several buckles 63 are uniformly arranged in an array along the length direction of the cooling cover 6 at the connection of the left cover body 61 and the right cover body 62. When it is necessary to clean or replace the inside of the cooling cover 6, only need to open the buckles 63, and the left cover body 61 and the right cover body 62 can be separated, so as to disassemble the cooling cover 6.

[0052] Refer to Figure 3 , in order to improve the connection strength between the left cover body 61 and the right cover body 62, positioning grooves 611 (see Figure 7 ) are arranged at the top and bottom of the left cover body 61, and positioning blocks 621 matched with the positioning grooves 611 are arranged on the right cover body 62. When splicing, the positioning blocks 621 are embedded in the positioning grooves 611, which can play a role in positioning and supporting the left cover body 61 and the right cover body 62.

[0053] Refer to Figure 3 , to further improve the cooling effect of the cooling cover 6 on the outer cylinder 5, a number of rollers 64 are arranged in a circumferential array around the outer cylinder 5 at both ends of the cooling cover 6. The rotating shafts of the rollers 64 are parallel to the axis of the outer cylinder 5. The rollers 64 are arranged inside the cooling cover 6. By arranging the rollers 64, the cooling cover 6 can rotate relative to the outer cylinder 5, so that the axial flow fan 7 can cool the outer cylinder 5 in all directions, further improving the cooling effect of the axial flow fan 7.

[0054] Refer to Figure 4 and Figure 5, in order to stably rotate the cooling cover 6, convex rings 8 are provided on the outer peripheral surface of the outer cylinder 5 at both ends of the cooling cover 6. The convex rings 8 are arranged in contact with the side surfaces at both ends of the cooling cover 6. The convex rings 8 can play a limiting role in the axial direction of the cooling cover 6, restricting the cooling cover 6 to rotate only around the outer cylinder 5. A driving system for driving the rotation of the cooling cover 6 is also provided on the outer cylinder 5. The driving system can drive the cooling cover 6 to rotate, improving the stability of the heat dissipation process.

[0055] In addition, referring to Figure 4 and Figure 5 , since the cooling cover 6 needs to rotate 360°, in order to stably supply power to the axial flow fan 7, annular grooves 91 cooperating with the convex rings 8 are provided at both ends of the cooling cover 6. Conductive rings 81 connected to the power supply are provided on the side surfaces of the convex rings 8. The conductive rings 81 are coaxially arranged with the convex rings 8. Conductive sheets 92 in contact with the conductive rings 81 are provided on the side walls of the annular grooves 91. The axial flow fan 7 is electrically connected to the conductive sheets 92. After the left cover body 61 and the right cover body 62 are installed, the convex rings 8 can enter the annular grooves 91. At this time, the conductive sheets 92 can be in contact with the conductive rings 81, thus stably supplying power to the axial flow fan 7. And by arranging the conductive sheets 92 in the annular grooves 91, the annular grooves 91 can shield and protect the conductive sheets 92, improving the safety during use.

[0056] Referring to Figure 4 and Figure 5 , in order not to affect the installation of the left cover body 61 and the right cover body 62, connection rings 9 are provided around the convex rings 8 on the end faces of the cooling cover 6. The thickness of the connection rings 9 is greater than that of the convex rings 8, and the inner diameter of the connection rings 9 is smaller than the outer diameter of the convex rings 8. The annular grooves 91 are provided on the inner peripheral surfaces of the connection rings 9. In this way, when installing, the left cover body 61 and the right cover body 62 can be directly slid horizontally. The driving system includes gear teeth 82 provided on the outer peripheral surface of the convex ring 8. The gear teeth 82 are arranged in a circumferential array on the convex ring 8. A gear 65 meshing with the gear teeth 82 is rotatably connected to the cooling cover 6. The gear 65 is rotatably arranged at the end of the cooling cover 6. A notch communicating with the annular groove 91 is provided on the connection ring 9. The gear 65 meshes with the gear teeth 82 through the notch. A driving member for driving the rotation of the gear 65 is provided on the cooling cover 6. During operation, the driving member drives the gears 65 at both ends of the cooling cover 6 to rotate. Since the gear 65 meshes with the gear teeth 82 and the convex ring 8 is fixed, the cooling cover 6 can be driven to rotate. The structure is simple and the operation is convenient.

[0057] In this embodiment, referring to Figure 2 and Figure 3The driving part is a motor 66. There can be four motors 66, which are symmetrically fixed in pairs at the ends of the cooling cover 6. The output shaft of the motor 66 is parallel to the axis of the outer cylinder 5 and is connected to the gear 65. The motor 66 is electrically connected to the conductive sheet 92. When the motor 66 is turned on, the gear 65 can be driven to rotate, thereby driving the cooling cover 6 to rotate as a whole.

[0058] Reference Figure 3 as well as Figure 6 In order to facilitate the fixation of the cooling cover 6 when it is not necessary to rotate the cooling cover 6, a positioning pin 93 is slidably connected to the side of the connecting ring 9 along the axial direction of the outer cylinder 5, and a positioning hole 83 cooperating with the positioning pin 93 is provided on the convex ring 8. When it is not necessary to rotate the cooling cover 6, the driving part is closed and the positioning pin 93 is inserted into the positioning hole 83, so that the rotation of the cooling cover 6 can be limited and the cooling cover 6 can be fixed on the outer cylinder 5.

[0059] The implementation principle of this embodiment is as follows: when working, the cooling pump delivers the cooling medium in the liquid storage tank into the cooling channel 41, and the cooling medium takes away the heat on the barrel. After the cooling medium is output from the cooling channel 41, it is cooled by the heat exchanger and flows back to the liquid storage tank; while the cooling pump is working, the axial flow fan 7 is turned on, and the air flow passes through the outer wall of the outer cylinder 5 and is output from the ventilation hole 72, and the axial flow fan 7 dissipates heat to the outer wall of the outer cylinder 5; when you want to disassemble the cooling cover 6, open the buckle 63 and slide the left cover body 61 and the right cover body 62 in the horizontal direction.

[0060] Embodiment three:

[0061] A three-stage extrusion device for serial polymer foam extrusion processing, referring to Figure 7 , which is different from the first embodiment, in this embodiment, the driving member does not use the motor 66, and a wind wheel 10 is connected to rotate along the length direction of the cooling cover 6 in the cooling cover 6. The wind wheel 10 is eccentrically arranged relative to the axial flow fan. Both ends of the wind wheel 10 are connected to the gears 65 after extending out of the cooling cover 6. When the axial flow fan 7 rotates, the axial flow fan 7 blows the wind wheel 10, and the rotation of the wind wheel 10 can drive the gears 65 at both ends of the cooling cover 6 to rotate, thereby realizing the rotation of the cooling cover 6. Gears 65 are arranged at both ends of the wind wheel 10.

[0062] In addition, in order to stably realize the driving of the cooling hood 6, there are two wind wheels 10, and the two wind wheels 10 are symmetrical about the center of the outer cylinder 5. Gears 65 are provided at both ends of the two wind wheels 10, so that the axial flow fans 7 located on both sides of the cooling hood 6 can play a role in the rotation of the cooling hood 6, and the driving of the cooling hood 6 can be realized more stably.

[0063] In this embodiment, the wind wheel 10 includes an axle 101 and blades 102 arranged in a circular array on the surface of the axle 101. The two ends of the axle 101 are rotatably connected to the two ends of the cooling cover 6 and extend out of the cooling cover 6. The axle 101 is staggered relative to the axial flow fan 7, so that when the axial flow fan 7 is turned on, the axial flow fan 7 can blow the wind wheel 10 to rotate.

[0064] The embodiments of this specific implementation method are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A three - stage extrusion device for serial polymer foaming extrusion processing, including a first - stage extruder (1) for heating and plasticizing raw materials. A raw material feeder (11) is provided on the first - stage extruder (1). It is characterized in that: The discharge end of the first - stage extruder (1) is connected to a second - stage extruder (2) for adding additives to the raw materials. An additive feeder (21) is provided on the second - stage extruder (2); the output end of the second - stage extruder (2) is connected to a third - stage extruder (3) for cooling and homogenizing the raw materials; the barrel of the third - stage extruder (3) is composed of an inner barrel (4) and an outer barrel (5) which are sleeved with each other. A spiral cooling channel (41) is provided on the outer peripheral surface of the inner barrel (4). The cooling channel (41) includes a spiral groove provided on the outer surface of the inner barrel (4). Liquid inlet pipes (51) and liquid outlet pipes (52) are provided at both ends of the outer barrel (5). The liquid inlet pipes (51) and the liquid outlet pipes (52) are respectively communicated with both ends of the cooling channel (41). A heat exchanger and a cooling pump are connected in series between the liquid inlet pipe (51) and the liquid outlet pipe (52). A liquid storage tank for storing a cooling medium is also included, and the cooling pump is placed in the liquid storage tank; A cooling cover (6) is provided outside the outer barrel (5). The cooling cover (6) is arranged around the outer barrel (5). An axial - flow fan (7) is provided on the cooling cover (6). An air inlet hole (71) communicated with the air outlet of the axial - flow fan (7) is provided on the cooling cover (6). The axial - flow fans (7) are several. The several axial - flow fans (7) are arranged in an array along the length direction of the cooling cover (6) on the cooling cover (6). Several ventilation holes (72) for the air flow to flow out are provided on the cooling cover (6); Several rollers (64) are arranged in a circumferential array around the outer barrel (5) at both ends of the cooling cover (6). The rotation axes of the rollers (64) are arranged parallel to the axis of the outer barrel (5). Convex rings (8) are provided on the outer peripheral surface of the outer barrel (5) at both ends of the cooling cover (6). Annular grooves (91) matched with the convex rings (8) are provided at both ends of the cooling cover (6). A conductive ring (81) connected to a power source is provided on the side surface of the convex ring (8). A conductive sheet (92) in contact with the conductive ring (81) is provided on the annular groove (91). The axial - flow fan (7) is electrically connected to the conductive sheet (92); A driving system for driving the cooling cover (6) to rotate is also included.

2. The three - stage extrusion device for serial polymer foaming extrusion processing according to claim 1, It is characterized in that: A polymer melt cooler (12) is provided between the first - stage extruder (1) and the second - stage extruder (2).

3. The three - stage extrusion device for serial polymer foaming extrusion processing according to claim 1 or 2, It is characterized in that: The discharge end of the third - stage extruder (3) is connected to a static mixer (31), and the rear end of the static mixer (31) is connected to a mold (32).

4. The three - stage extrusion device for serial polymer foaming extrusion processing according to claim 3, It is characterized in that: The length-diameter ratio of the first-order extruder (1) is 16:1 - 32:1, the length-diameter ratio of the second-order extruder (2) is 24:1 - 64:1, the length-diameter ratio of the third-order extruder (3) is 16:1 - 36:1, and the rotational speed of the second-order extruder (2) is lower than that of the first-order extruder (1).

5. The three-stage extrusion device for serial polymer foaming extrusion processing according to claim 1, characterized in that: The vertical section of the cooling cover (6) is arranged in a regular octagon shape. The axial flow fans (7) are arranged in two columns and symmetrically on both sides of the cooling cover (6). The ventilation holes (72) are arranged on the top surface and the bottom surface of the cooling cover (6). The cooling cover (6) is composed of a left cover body (61) and a right cover body (62) which are symmetrically arranged. The left cover body (61) and the right cover body (62) are symmetrically arranged about the length direction of the barrel. The left cover body (61) and the right cover body (62) are fixedly connected by a buckle (63).

6. The three-stage extrusion device for serial polymer foaming extrusion processing according to claim 1, characterized in that: The drive system includes gear teeth (82) arranged on the outer peripheral surface of the convex ring (8). The gear teeth (82) are arranged in a circumferential array on the convex ring (8). A gear (65) meshing with the gear teeth (82) is rotatably connected to the cooling cover (6). A driving member for driving the gear (65) to rotate is arranged on the cooling cover (6).

7. The three-stage extrusion device for serial polymer foaming extrusion processing according to claim 6, characterized in that: Circular connecting rings (9) are arranged around the convex ring (8) at both ends of the cooling cover (6). An annular groove (91) is arranged on the inner surface of the connecting ring (9). A positioning pin (93) is slidably connected to the side surface of the connecting ring (9) along the axis direction of the outer cylinder (5). A positioning hole (83) cooperating with the positioning pin (93) is arranged on the convex ring (8).

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