Extrusion mechanism capable of precisely controlling temperature

Abstract

The extrusion mechanism comprises a gun barrel, a screw rod, an outer heating device and an inner heating assembly, a feeding hopper is arranged at the top of the gun barrel, a heating inner cavity is formed in the screw rod, and the inner heating assembly comprises a medium pipe; the inner heating assembly further comprises a backflow cover which is arranged on the side wall of the inlet end of the medium pipe, a center opening for containing the medium pipe is formed in the center of the backflow cover, the end, away from the center opening, of the backflow cover extends in the direction close to the outlet of the medium pipe, and the end, facing the outlet of the medium pipe, of the backflow cover is rotationally connected with the outer wall of the screw in a sealed mode through a sealing bearing. The end, close to the inlet of the backflow cover, of the heating inner cavity communicates with the backflow cover inner cavity, and the bottom of the backflow cover is connected with a liquid outlet pipe. The heating temperature of the material is controlled by controlling the oil temperature, so that the temperature is more stable, meanwhile, the material is conveniently and rapidly cooled, when maintenance is needed, the maintenance time is shortened through rapid cooling, the material can be immediately put into production after maintenance is completed, and the production efficiency is improved.

Description

Technical Field

[0001] This application relates to the field of extruders, and more particularly to an extrusion mechanism for precise temperature control. Background Technology

[0002] Extrusion granulators are widely used in the plastics industry and are a common type of extrusion granulation equipment. In the production of plastic lunch boxes, granular plastic is melted in an extruder and extruded into sheets. These sheets are then pressed and cut to obtain the final lunch box.

[0003] Typically, extruders rely on heating wires on the outer wall of the barrel to heat and melt the material inside. The rotating or pushing screw inside the barrel then propels the molten material through the die. In this traditional structure, the barrel only provides heating, and the screw only propels the material forward. However, the material inside the barrel takes a long time to heat and melt, especially the material near the screw's outer wall, which is furthest from the inner wall. This results in a significant delay in the extruder's warm-up process during startup, severely impacting production efficiency.

[0004] Patent application No. 201910426231.1 discloses a heating screw for extruders and injection molding machines, including a screw body with a hollow structure. A heating rod is inserted into the inner cavity of the screw body. A bidirectional bearing is installed at both the front and rear ends of the heating rod. The bidirectional bearing includes an inner ring, an outer ring, and first balls. The inner ring is fitted inside the outer ring. Multiple first balls are arranged between the inner and outer rings. A convex annular stepped structure is formed on the outer circumference of the outer ring. An auxiliary pressure ring is provided at the annular step. Multiple second balls are arranged circumferentially between the auxiliary pressure ring and the stepped plane of the annular step. Multiple third balls are arranged circumferentially between the auxiliary pressure ring and the stepped plane.

[0005] While the aforementioned technology achieves the effect of simultaneously heating the material between the barrel and the screw from both inside and outside, the heating rod typically uses a temperature sensor to control the temperature. When the temperature is too high, the heating rod stops working, and when the temperature is too low, the heating rod starts working. This results in poor temperature control and is prone to problems such as insufficient or excessive temperature. At the same time, when the material temperature is high, it is difficult to cool down quickly because the screw is covered by multiple layers, making it difficult to accurately control the material temperature. Summary of the Invention

[0006] In order to more accurately control the temperature of the material inside the extruder, this application provides an extrusion mechanism for precise temperature control.

[0007] This application provides an extrusion mechanism for precise temperature control, which adopts the following technical solution:

[0008] An extrusion mechanism for precise temperature control includes a barrel, a screw, an external heating device, and an internal heating assembly. The barrel has a feed hopper at its top, and the screw has a heating chamber inside. The internal heating assembly includes a medium pipe rotatably connected to the heating chamber via a rotating bearing. The outer diameter of the medium pipe is smaller than the inner diameter of the heating chamber. The heating chamber is closed at its end near the discharge end of the barrel, and the outlet of the medium pipe connects to the gap between the medium pipe and the heating chamber. The internal heating assembly also includes a reflux shroud, which is located on the side wall at the inlet end of the medium pipe. The reflux shroud has a central opening for accommodating the medium pipe, and its end away from the central opening extends towards the outlet of the medium pipe. The end of the reflux shroud facing the outlet of the medium pipe is rotatably and sealingly connected to the outer wall of the screw via a sealing bearing. The end of the heating chamber near the inlet of the reflux shroud connects to the inner cavity of the reflux shroud, and a liquid outlet pipe is connected to the bottom of the reflux shroud.

[0009] By adopting the above technical solution, a screw rotating inside the barrel propels the material forward. An external heating device heats the outer wall of the barrel, while an internal heating component heats the material within the heating cavity, achieving dual heating from both inside and outside, thus enabling rapid heating of the material. During internal heating, hot oil is pumped into the medium pipe through the inlet. The hot oil flows through the medium pipe cavity and reaches the outlet. It then flows back through the gap between the medium pipe and the heating cavity, entering the return shroud, and finally exiting through the outlet pipe. This heating method controls the material's heating temperature by controlling the oil temperature, resulting in a more stable temperature. Simultaneously, when cooling is needed, a radiator connected to the inlet pipe dissipates heat from the oil, allowing for convenient and rapid cooling of the material. When maintenance is required, rapid cooling reduces maintenance time, allowing for immediate resumption of production after maintenance, thus improving production efficiency.

[0010] Optionally, the outer wall of the medium tube is provided with a drainage thread, the inlet of the medium tube is connected to a medium box, and the bottom of the medium box is higher than the center opening.

[0011] By adopting the above technical solution and setting the flow-guiding thread, when the screw rotates, the medium pipe and the screw rotate relative to each other, thereby guiding the hot oil towards the direction of the return shroud. There is no need for the pump body to drive the hot oil flow, reducing the driving device, using less electricity, and saving production costs.

[0012] Optionally, the inner wall of the reflux hood is provided with an annular groove, and the liquid outlet pipe is connected to the bottom of the annular groove.

[0013] By adopting the above technical solution and setting up an annular groove, hot oil enters the annular groove first after entering the reflux shroud, thus facilitating the entry of hot oil into the outlet pipe.

[0014] Optionally, the top of the return shroud is provided with an exhaust pipe, and the top of the exhaust pipe is provided with a threaded cap that seals the top of the exhaust pipe, and the threaded cap is screwed tightly onto the top of the exhaust pipe.

[0015] By adopting the above technical solution, the exhaust pipe is designed so that when hot oil first enters the reflux shroud, the threaded cap is opened, and when the reflux pipe is full of oil, the threaded cap is closed. This keeps the reflux shroud full of oil, making it less likely for air bubbles to exist in the heating chamber, ensuring that the screw is heated evenly, and thus the material is heated evenly.

[0016] Optionally, the exhaust pipe is a transparent pipe.

[0017] By adopting the above technical solution, it is convenient to observe the oil level in the return shroud. When the oil level is lower than the bottom of the exhaust pipe, the threaded cap can be opened to exhaust the oil.

[0018] Optionally, the external heating device includes multiple heating sleeves that are sleeved side by side on the outer wall of the gun barrel, and a heating tube for heating the gun barrel is provided inside the heating sleeve; a clamping cavity is provided inside the heating sleeve, and an interface for connecting the clamping cavity is provided on the outer wall of the heating sleeve, a fan is connected to the interface, and an air outlet communicating with the clamping cavity is provided on the outer wall of the heating sleeve.

[0019] By adopting the above technical solution, multiple heating jackets are installed side by side on the outer wall of the gun barrel. The temperature of each heating jacket can be controlled individually to achieve heating temperatures at different stages and locations, thus realizing segmented heating. After the fan operates, it cools the heating tubes in the clamping cavity, achieving rapid cooling of the outer wall of the gun barrel. When maintenance is required, the dual rapid cooling of the outer wall of the gun barrel and the screw reduces maintenance time. After maintenance is completed, production can be resumed immediately, improving production efficiency.

[0020] Optionally, a gas collecting cylinder is provided in the middle of the barrel, a pressure relief valve is provided at the top of the gas collecting cylinder, and a pressure gauge is provided on the gas collecting cylinder.

[0021] By adopting the above technical solution, water vapor is generated after the material is heated. The water vapor accumulates in the gas collection cylinder. By observing the pressure gauge, when the pressure is high, the pressure relief valve is opened to release the gas. If the gas is not released, the plastic products will contain air bubbles, which will affect sales.

[0022] Optionally, it also includes a drive assembly for rotating the screw. The drive assembly includes a drive wheel, a driven wheel, a belt, and a drive motor. The drive wheel is coaxially fixed to the shaft of the drive motor, and the driven wheel is coaxially fixed to the outer wall of the screw. The belt is tensioned and connected to the drive wheel and the driven wheel. The outer diameter of the driven wheel is larger than the outer diameter of the drive wheel.

[0023] By adopting the above technical solution, the drive motor drives the active wheel to rotate, thereby driving the driven wheel to rotate. Because the outer diameter of the driven wheel is larger than that of the active wheel, the speed is reduced, so that both the material and the hot oil move slowly, thus ensuring that the material is heated fully and that the hot oil does not flow too fast, causing the temperature to rise.

[0024] In summary, this application includes at least one of the following beneficial technical effects:

[0025] 1. By controlling the oil temperature, the heating temperature of the material is controlled, making the temperature more stable and also allowing the material to cool down quickly. When maintenance is required, the rapid cooling reduces maintenance time, and the material can be put into production immediately after maintenance, thus improving production efficiency.

[0026] 2. By setting a drainage thread, there is no need to set up a pump to drive the hot oil flow, saving costs;

[0027] 3. By setting an exhaust pipe and a threaded cap, air bubbles are less likely to exist in the heating cavity, ensuring that the material is heated evenly. Attached Figure Description

[0028] Figure 1 This is an overall schematic diagram of the temperature-controlled extrusion mechanism according to an embodiment of this application (showing the complete structure of the temperature-controlled extrusion mechanism installed on the extruder).

[0029] Figure 2 yes Figure 1 AA-line cross-section view.

[0030] Figure 3 yes Figure 1 The enlarged view at point B mainly shows the structure of the gas collecting cylinder and the heating jacket.

[0031] Figure 4 yes Figure 2 The enlarged view at point C mainly shows the internal structure of the screw.

[0032] Figure 5 This is a partial split diagram of an embodiment.

[0033] Figure 6 yes Figure 5 The enlarged view at point D mainly shows the structure of the return shroud and drive assembly.

[0034] Explanation of reference numerals in the attached drawings: 1. Barrel; 11. Gas collecting cylinder; 111. Pressure relief valve; 112. Pressure gauge; 12. Feed hopper; 2. Screw; 21. Connecting bearing; 22. Heating inner cavity; 3. External heating device; 31. Heating jacket; 311. Interface; 312. Air outlet; 32. Fan; 4. Internal heating assembly; 41. Medium pipe; 411. Sealed bearing; 412. Drainage thread; 413. Rotating bearing; 42. Return hood; 421. Center port; 422. Liquid inlet pipe; 5. Medium tank; 51. Controller; 53. Circular groove; 54. Liquid outlet pipe; 6. Radiator; 7. Exhaust pipe; 71. Threaded cap; 8. Drive assembly; 81. Drive wheel; 82. Driven wheel; 83. Belt; 84. Drive motor. Detailed Implementation

[0035] The following is in conjunction with the appendix Figures 1-6 This application will be described in further detail.

[0036] This application discloses an extrusion mechanism for precise temperature control. (Refer to...) Figure 1 and Figure 2 The temperature-controlled extrusion mechanism includes a barrel 1, a screw 2, an external heating device 3, and an internal heating component 4.

[0037] Reference Figure 3 The external heating device 3 includes multiple heating sleeves 31 arranged side-by-side on the outer wall of the barrel 1. These heating sleeves 31 operate independently, enabling segmented heating of the barrel 1. A heating tube (not shown in the figure) for heating the barrel 1 is fixed inside each heating sleeve 31; the heating tube is an electric heating element that heats up when energized. A cavity (not shown in the figure) is formed inside each heating sleeve 31, and the heating tube is fixed to the side wall of the cavity near the barrel 1. An interface 311 connecting to the cavity is formed on the outer wall of the heating sleeve 31, and a fan 32 is connected to the interface 311. An air outlet 312 communicating with the cavity is formed on the outer wall of the heating sleeve 31 on the side opposite to the interface 311, allowing air generated by the fan 32 to be blown out.

[0038] Reference Figure 3 Two heating jackets 31 are spaced apart, and a gas collecting cylinder 11 is installed in the space between them. The gas collecting cylinder 11 is connected to the inner cavity of the middle section of the barrel 1. A pressure relief valve 111 is connected to the top of the gas collecting cylinder 11. A pressure gauge 112 is also connected to the top of the gas collecting cylinder 11. When the pressure gauge 112 shows too high pressure, the pressure relief valve 111 is opened to release pressure and prevent the water vapor produced after the material is heated from affecting the quality of the plastic product.

[0039] Reference Figure 1 A feed hopper 12 is fixed at the top of the starting end of the barrel 1, and the material enters the barrel 1 from the feed hopper 12.

[0040] Reference Figure 3 , Figure 4The end of the screw 2 near the feed hopper 12 is rotatably connected to the inner wall of the barrel 1 via a connecting bearing 21, which is located on the side of the feed hopper 12 away from the gas collecting cylinder 11. A heating cavity 22 is provided inside the screw 2, which extends along the length of the screw 2. The end of the screw 2 near the feed hopper 12 is open, while the end of the screw 2 away from the feed hopper 12 is closed.

[0041] Reference Figure 4 The internal heating assembly 4 includes a medium pipe 41 and a return shroud 42. The medium pipe 41 is rotatably connected to the heating inner cavity 22 via a rotating bearing 413. Both ends of the medium pipe 41 are rotatably connected to the heating inner cavity 22 via rotating bearings 413. The outer diameter of the medium pipe 41 is smaller than the inner diameter of the heating inner cavity 22. Both ends of the medium pipe 41 are open. The outlet of the medium pipe 41 connects the gap between the medium pipe 41 and the heating inner cavity 22.

[0042] Reference Figure 5 , Figure 6 The return shroud 42 is fixed to the medium pipe 41 (see...) Figure 4 The side wall at the inlet end of the reflux shroud 42 has a central opening 421 for accommodating the medium pipe 41, with the end of the medium pipe 41 located at the central opening 421 serving as its inlet. The end of the reflux shroud 42 away from the central opening 421 extends towards the outlet of the medium pipe 41. The end of the screw 2 near the feed hopper 12 is located inside the reflux shroud 42, and the end of the reflux shroud 42 facing the outlet of the medium pipe 41 is rotatably and sealingly connected to the outer wall of the screw 2 via a sealed bearing 411. The heating inner cavity 22 near the end of the reflux shroud 42 communicates with the inner cavity of the reflux shroud 42.

[0043] Reference Figure 4 , Figure 5 The outer wall of the medium pipe 41 is provided with a drainage thread 412, and the center port 421 is connected to an inlet pipe 422 that communicates with the medium pipe 41. The end of the inlet pipe 422 away from the medium pipe 41 is connected to a medium tank 5. The medium tank 5 is used to hold hot oil. A heating wire is provided inside the medium tank 5 to heat the oil. A controller 51 is fixed on the outer wall of the medium chamber. The controller 51 displays the temperature inside the heating tank and the oil level. It is also provided with a button for adjusting the heating temperature. The bottom of the medium tank 5 is higher than the center port 421. The oil is pushed into the inlet pipe 422 by rotating the drainage thread 412.

[0044] Reference Figure 4 , Figure 5 A radiator 6 is connected to the inlet pipe 422. When the screw 2 needs to be cooled, the radiator 6 is turned on and the heating wire for oil heating is turned off to achieve rapid cooling.

[0045] Reference Figure 4 , Figure 6The inner wall of the reflux shroud 42 is provided with an annular groove 53, which is coaxial with the medium pipe 41. The axis of the annular groove 53 is horizontal. The bottom of the annular groove 53 is connected to the liquid outlet pipe 54, and the end of the liquid outlet pipe 54 away from the reflux shroud 42 is connected to the top surface of the medium tank 5, thereby realizing reflux.

[0046] An exhaust pipe 7 is fixed to the top of the return shroud 42. The exhaust pipe 7 is a transparent pipe. A threaded cap 71 that seals the top of the exhaust pipe 7 is threaded to the top of the exhaust pipe 7. The inner wall of the threaded cap 71 is provided with an internal thread, and the outer wall of the top of the exhaust pipe 7 is provided with an external thread. The threaded cap 71 is screwed tightly to the top of the exhaust pipe 7.

[0047] Reference Figure 6 The temperature-controlled extrusion mechanism also includes a drive assembly 8 that drives the screw 2 to rotate. The drive assembly 8 includes a drive wheel 81, a driven wheel 82, a belt 83, and a drive motor 84. The drive wheel 81 is coaxially fixed to the shaft of the drive motor 84, the driven wheel 82 is coaxially fixed to the outer wall of the screw 2, and the belt 83 is tensioned and connected to the drive wheel 81 and the driven wheel 82. The outer diameter of the driven wheel 82 is larger than the outer diameter of the drive wheel 81 to achieve speed reduction.

[0048] The implementation principle of the temperature-controlled extrusion mechanism in this application embodiment is as follows: During operation, the screw 2 is rotatably connected inside the barrel 1 to push the material forward, the external heating device 3 heats the outer wall of the barrel 1, and the internal heating component 4 is located in the heating inner cavity 22 to heat the material, thereby achieving dual heating inside and outside, and thus achieving rapid heating of the material.

[0049] When the internal heating component 4 is heating, the medium pipe 41 and the screw 2 rotate relative to each other, thereby drawing hot oil from the medium tank 5 into the inlet pipe 422, and then passing through the inner cavity of the medium pipe 41, the gap between the medium pipe 41 and the heating inner cavity 22, the inner cavity of the return shroud 42 and the outlet pipe 54, and finally returning to the medium tank 5.

[0050] When the screw 2 needs cooling for maintenance, the radiator 6 and fan 32 are turned on to achieve simultaneous heat dissipation from both inside and outside the barrel 1, resulting in rapid heat dissipation. This heating method controls the material heating temperature by controlling the oil temperature, making the temperature more stable. Production can be resumed immediately after maintenance, improving production efficiency.

[0051] In summary, the solution proposed in this application facilitates rapid heating of materials and rapid cooling of the inside and outside of the barrel 1, thereby improving production efficiency, facilitating the control of material temperature, and making the material temperature more stable.

[0052] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An extrusion mechanism for precise temperature control, comprising a barrel (1), a screw (2), an external heating device (3), and an internal heating assembly (4), wherein a feed hopper (12) is provided at the top of the barrel (1), characterized in that: The screw (2) is provided with a heating inner cavity (22). The inner heating assembly (4) includes a medium pipe (41), which is rotatably connected to the heating inner cavity (22) via a rotating bearing (413). The outer diameter of the medium pipe (41) is smaller than the inner diameter of the heating inner cavity (22). The end of the heating inner cavity (22) near the discharge end of the barrel (1) is closed. The outlet of the medium pipe (41) connects the gap between the medium pipe (41) and the heating inner cavity (22). The inner heating assembly (4) also includes a return shroud (42), which is disposed in... The side wall at the inlet end of the medium tube (41) has a central opening (421) for accommodating the medium tube (41) in the center of the reflux shroud (42). The end of the reflux shroud (42) away from the central opening (421) extends towards the outlet of the medium tube (41). The end of the reflux shroud (42) facing the outlet of the medium tube (41) rotates and seals the outer wall of the connecting screw (2) through the sealing bearing (411). The end of the heating inner cavity (22) near the inlet of the reflux shroud (42) is connected to the inner cavity of the reflux shroud (42). The bottom of the reflux shroud (42) is connected to the liquid outlet pipe (54).

2. The extrusion mechanism for precise temperature control according to claim 1, characterized in that: The outer wall of the medium tube (41) is provided with a drainage thread (412), and the inlet of the medium tube (41) is connected to a medium box (5). The bottom height of the medium box (5) is higher than the center opening (421).

3. The extrusion mechanism for precise temperature control according to claim 1, characterized in that: The inner wall of the reflux hood (42) is provided with an annular groove (53), and the liquid outlet pipe (54) is connected to the bottom of the annular groove (53).

4. The extrusion mechanism for precise temperature control according to claim 1, characterized in that: The top of the return shroud (42) is provided with an exhaust pipe (7), and the top of the exhaust pipe (7) is provided with a threaded cap (71) that seals the top of the exhaust pipe (7), and the threaded cap (71) is screwed onto the top of the exhaust pipe (7).

5. The extrusion mechanism for precise temperature control according to claim 4, characterized in that: The exhaust pipe (7) is a transparent pipe.

6. The extrusion mechanism for precise temperature control according to claim 1, characterized in that: The external heating device (3) includes multiple heating sleeves (31) that are sleeved side by side on the outer wall of the barrel (1). A heating tube for heating the barrel (1) is provided inside the heating sleeve (31). A clamping cavity is provided inside the heating sleeve (31). An interface (311) for connecting the clamping cavity is provided on the outer wall of the heating sleeve (31). A fan (32) is connected to the interface (311). An air outlet (312) for communicating with the clamping cavity is provided on the outer wall of the heating sleeve (31).

7. The extrusion mechanism for precise temperature control according to claim 1, characterized in that: A gas collecting cylinder (11) is provided in the middle of the barrel (1), a pressure relief valve (111) is provided at the top of the gas collecting cylinder (11), and a pressure gauge (112) is provided on the gas collecting cylinder (11).

8. The extrusion mechanism for precise temperature control according to claim 1, characterized in that: It also includes a drive assembly (8) for rotating the screw (2). The drive assembly (8) includes a drive wheel (81), a driven wheel (82), a belt (83), and a drive motor (84). The drive wheel (81) is coaxially fixed on the shaft of the drive motor (84). The driven wheel (82) is coaxially fixed on the outer wall of the screw (2). The belt (83) is tensioned and connected to the drive wheel (81) and the driven wheel (82). The outer diameter of the driven wheel (82) is larger than the outer diameter of the drive wheel (81).

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