A twin screw extruder

Abstract

The present invention relates to the technical field of plastic processing, and in particular to a twin-screw extruder, comprising a driving motor, a frame, a gear transmission, an extrusion barrel and a twin-screw arranged inside the extrusion barrel, a horizontally arranged conveying barrel is installed on the upper part of the frame through a supporting frame, the bottom of the conveying barrel is connected with the feeding end of the extrusion barrel through a feeding pipe, a conveying motor is arranged on the end of the conveying barrel away from the feeding pipe, the output shaft of the conveying motor rotates through a rotating hole to penetrate into the interior of the conveying barrel, and is transmission-connected with a feeding regulating mechanism, a feeding hopper connected to the interior of the conveying barrel is arranged on the top of the conveying barrel, and the design of the feeding regulating mechanism can avoid excessive pressure inside the feeding pipe, prevent the conveying motor from being overloaded, and affect its service life.

Description

Technical Field

[0001] The invention relates to the technical field of plastic processing, in particular to a twin-screw extruder. Background Art

[0002] The twin-screw extruder in plastic processing is a commonly used equipment, which consists of several parts such as a transmission device, a feeding device, a barrel and a screw. It has good feeding performance, mixing and plasticizing performance, exhaust performance, extrusion stability and other characteristics. It is used to heat, compress and extrude plastic raw materials. The plastic raw materials are fed into the barrel from the feed port, and the twin-screw extruder is equipped with a heating system to heat the plastic raw materials to the melting temperature. The molten plastic raw materials are compressed through mechanical action and then extruded.

[0003] When a twin-screw extruder is in use, in order to ensure that there is no problem of uneven discharge, it is necessary to maintain stable feeding. However, the existing feeding device cannot reasonably balance and stably feed according to the pressure, and it is easy to cause material breakage and uneven discharge. In addition, an existing method of feeding is to use a spiral conveyor. However, in this case, it is not easy to adjust and control the feeding speed. Once the feeding is too fast, the internal pressure is too high, which can easily cause the feeding motor to overload and affect its service life. Summary of the invention

[0004] The purpose of the present invention is to provide a twin-screw extruder to solve the problems in the prior art that the twin-screw extruder has unstable feeding and is difficult to adjust and control the feeding speed. Once the feeding is too fast, the internal pressure is too large, which easily causes the feeding motor to overload.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A twin-screw extruder comprises a driving motor, a frame, a gear transmission, an extrusion barrel and a twin-screw arranged inside the extrusion barrel, a horizontally arranged conveying barrel is installed on the upper part of the frame through a support frame, the bottom of the conveying barrel is connected with the feeding end of the extrusion barrel through a feeding pipe, a conveying motor is arranged on the end of the conveying barrel away from the feeding pipe, the output shaft of the conveying motor rotates through a rotating hole and penetrates into the interior of the conveying barrel, and is transmission-connected with a feeding adjustment mechanism, and a feeding hopper connected to the interior of the conveying barrel is arranged on the top of the conveying barrel;

[0007] The feeding adjustment mechanism includes a sleeve, a transmission rod and a piston block. The piston block is slidably arranged inside the conveying cylinder. A support rebound component is provided on the piston block. A movable hole running through both sides of the piston block is opened on the piston block, and a sealed bearing is installed in the movable hole; one end of the transmission rod is transmission-connected with the output shaft of the conveying motor, and the other end of the transmission rod movably passes through the inner ring of the sealed bearing, and is rotationally connected with the inner wall of the conveying cylinder away from the conveying motor through the rotating bearing, and a sliding strip parallel to the transmission rod is provided on the outer wall of the transmission rod; the sleeve is sleeved on the outer side of the transmission rod, and one end of the sleeve is fixedly connected to the inner ring of the sealed bearing, and a sliding groove running through both ends of the sleeve is opened on the inner wall of the sleeve along its axis, and a spiral conveying blade is provided on the outer wall of the sleeve;

[0008] The bottom side of the conveying cylinder is connected with a buffer tube, and the bottom of the piston block away from the conveying motor is connected with an isolation plate, which is used to close the top of the buffer tube.

[0009] A further technical solution is that a plurality of mounting grooves are opened along the path of the inner walls on opposite sides of the slide groove, and a movable wheel is arranged in the mounting groove for rotation through a fixing pin, and the wheel surface of the movable wheel is protruding from the groove opening of the mounting groove away from the bottom of the mounting groove.

[0010] A further technical solution is to have two slide bars and two slide grooves, the two slide bars are symmetrically arranged on the outer wall of the transmission rod with the axis of the transmission rod as the symmetry axis, and the two slide grooves are symmetrically arranged on the inner wall of the sleeve with the axis of the sleeve as the symmetry axis.

[0011] A further technical solution is that a sealing strip is provided at the opening of one end of the slide groove away from the piston block and at the opening of one end of the sleeve away from the piston block.

[0012] A further technical solution is that the support rebound assembly includes a support spring and a support ring. The support ring is movably sleeved on the outside of the transmission rod and placed between the piston block and the conveying motor. The support spring is sleeved on the outside of the transmission rod. One end of the support spring is fixedly connected to the piston block, and the other end is fixedly connected to the support ring.

[0013] A further technical solution is that two strip holes connected to the interior of the conveying cylinder are opened on the outer wall of one end close to the conveying motor, and the two strip holes are symmetrically arranged on the outer wall of the conveying cylinder. Two screws are connected to the support ring, and the ends of the two screws away from the support ring respectively pass through the two strip holes and are threadedly connected with nuts.

[0014] A further technical solution is that a scale line parallel to the strip hole is provided on the outer wall of the conveying cylinder.

[0015] A further technical solution is that a limit ring is fixedly sleeved on the end of the transmission rod away from the conveying motor.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] Through the design of the support rebound component, the piston block, the transmission rod, the slide bar, the sleeve, the slide groove, the spiral conveying blade and the buffer tube, during the spiral conveying process, when the internal pressure of the feed pipe is too large, the extrusion reaction force generated by the spiral conveying blade can be used to make the piston block and the spiral conveying blade slide along the transmission rod toward the conveying motor. The movement of the piston block will do work on the support rebound component, and at the same time, the isolation plate also moves with the piston block. The isolation plate no longer completely closes the top of the buffer tube, and the end of the spiral conveying blade away from the piston block moves to the upper part of the buffer tube. Since the buffer tube is located in front of the feed pipe relative to the material conveying direction inside the conveying cylinder, the material inside the conveying cylinder will be discharged through the buffer tube first, thereby slowing down the material entering the feed pipe. When the internal pressure of the feed pipe becomes smaller, the piston block is reset under the action of the support rebound component, thereby driving the isolation plate and the spiral conveying blade to reset, and the isolation plate closes the buffer tube. Through the above structure, the internal pressure of the feeding barrel can be avoided from being too large, and the conveying motor can be prevented from being overloaded, thereby affecting its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a schematic structural diagram of a twin-screw extruder.

[0019] Figure 2 It is a sectional view of a side view of the conveying tube of the present invention.

[0020] Figure 3 This is a sectional view of another state of the conveying tube of the present invention from the side.

[0021] Figure 4 It is a schematic diagram of the connection between the transmission rod, sleeve and spiral conveying blade of the present invention.

[0022] Figure 5 It is a schematic cross-sectional view of the three-dimensional structure of the sleeve of the present invention.

[0023] Figure 6 It is a top cross-sectional schematic diagram of the sleeve of the present invention.

[0024] Icons: 1-drive motor, 2-frame, 3-gear transmission, 4-extrusion barrel, 5-support frame, 6-conveying barrel, 7-feeding pipe, 8-conveying motor, 9-rotating hole, 10-feeding hopper, 11-sleeve, 12-transmission rod, 13-piston block, 14-sealed bearing, 15-rotating bearing, 16-slide bar, 17-slide groove, 18-spiral conveying blade, 19-buffer tube, 20-isolation plate, 21-mounting groove, 22-fixing pin, 23-movable wheel, 24-sealing strip, 25-support spring, 26-support ring, 27-bar hole, 28-screw, 29-nut, 30-scale line, 31-limiting ring, 32-transmission belt, 33-limiting block. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0026] Example 1

[0027] See also Figures 1 to 6 It is shown that a twin-screw extruder of the present invention comprises a driving motor 1, a frame 2, a gear transmission 3, an extrusion barrel 4 and a twin screw arranged inside the extrusion barrel 4, the driving motor 1 is installed at the lower part of the frame 2, the driving motor 1 is connected to one end of the gear transmission 3 through a transmission belt 32, the other end of the gear transmission 3 is connected to the twin screw arranged in the extrusion barrel 4, the gear transmission 3 is convenient for adjusting the speed, so as to control the extrusion rate, the twin screw is arranged in the extrusion barrel 4 by the installation method of the prior art, a horizontally arranged conveying barrel 6 is installed on the upper part of the frame 2 through a supporting frame 5, the bottom of the conveying barrel 6 is connected to the feeding end of the extrusion barrel 4 through a feeding pipe 7, a conveying motor 8 is provided on one end of the conveying barrel 6 away from the feeding pipe 7, the output shaft of the conveying motor 8 rotates through the rotating hole 9 to penetrate into the interior of the conveying barrel 6, and is connected to the feeding adjustment mechanism, a supporting bearing is provided in the rotating hole 9, the output shaft of the conveying motor 8 is fixedly connected to the inner ring of the supporting bearing to ensure its stable rotation, and a feeding hopper 10 connected to the interior of the conveying barrel 6 is provided at the top.

[0028] As a preferred embodiment, see Figures 2 to 4As shown, the feeding adjustment mechanism includes a sleeve 11, a transmission rod 12 and a piston block 13. The piston block 13 is slidably arranged inside the conveying cylinder 6. A support rebound component is provided on the piston block 13. A movable hole running through both sides of the piston block 13 is opened. A sealing bearing 14 is installed in the movable hole. A sealing rubber pad is fixedly connected to one side of the piston block 13. Through the design of the piston block 13 and the sealing rubber pad, the inner wall of the conveying cylinder 6 is set to a smooth surface to prevent the squeezed material from flowing out of one end of the conveying cylinder 6, and the friction between the piston block 13 and the sealing rubber pad and the inner wall of the conveying cylinder 6 is small, which does not affect the sliding of the piston block 13 along the conveying cylinder 6; one end of the transmission rod 12 is transmission-connected to the output shaft of the conveying motor 8, and the other end of the transmission rod 12 is movable through the inner ring of the sealing bearing 14, and by rotating the bearing 1 5 is rotatably connected with the inner wall of the end of the conveying cylinder 6 away from the conveying motor 8, and a sliding bar 16 parallel to the inner wall of the transmission rod 12 is provided; the sleeve 11 is sleeved on the outer side of the transmission rod 12, and one end of the sleeve 11 is fixedly connected with the inner ring of the sealing bearing 14. A sliding groove 17 penetrating through both ends of the sleeve 11 is opened on the inner wall of the sleeve 11 along its axis, and a spiral conveying blade 18 is provided on the outer wall of the sleeve 11; when the sleeve 11 is sleeved on the outer side of the transmission rod 12, the sliding bar 16 penetrates the sliding groove 17 and is slidably connected with the sliding groove 17. Through the design of the sliding bar 16 and the sliding groove 17, when the sleeve 11 is sleeved on the outer side of the transmission rod 12, the rotation of the transmission rod 12 can drive the sleeve 11 to rotate, and the sleeve 11 can also slide along the transmission rod 12. It should be noted that the length of the sliding bar 16 is longer than the length of the sleeve 11.

[0029] As a preferred embodiment, see Figure 2 , Figure 3 It is shown that a buffer tube 19 is connected to the bottom side of the conveying cylinder 6, and an isolation plate 20 is connected to the bottom of the side of the piston block 13 away from the conveying motor 8. The isolation plate 20 is used to close the top of the buffer tube 19. When the conveying cylinder 6 is not working, the isolation plate 20 is placed on the top of the buffer tube 19 to close the top of the buffer tube 19. When the isolation plate 20 follows the piston block 13 to move toward the conveying motor 8, the isolation plate 20 follows the movement of the buffer plate and no longer completely closes the top of the buffer tube 19. It should be noted that the isolation plate 20 can be set according to the shape of the inner wall of the conveying cylinder 6, so as to ensure that when the isolation plate 20 is set inside the conveying cylinder 6, the top of the buffer tube 19 can be closed.

[0030] When the present solution is actually used, through the design of the support rebound component, the piston block 13, the transmission rod 12, the slide bar 16, the sleeve 11, the slide groove 17, the spiral conveying blade 18 and the buffer tube 19, during the spiral conveying process, the material enters the interior of the conveying cylinder 6 from the feed hopper 10, and the conveying motor 8 drives the transmission rod 12 to rotate. At this time, through the setting of the slide bar 16 and the slide groove 17, the sleeve 11 follows the transmission rod 12 to rotate, and then drives the spiral conveying blade 18 to rotate to convey the material of the conveying cylinder 6 to the feed pipe 7, and finally enters the extrusion barrel 4, ensuring normal feeding. When the internal pressure of the feed pipe 7 is too large, the extrusion reaction force generated by the spiral conveying blade 18 can be used to make the piston block 13 and the spiral conveying blade 18 slide along the transmission rod 12 to move in the direction of the conveying motor 8. The movement of the piston block 13 will do work on the support rebound component, and at the same time, the isolation plate 20 also moves with the piston block 13, and the isolation plate 20 no longer moves on the buffer The top of the tube 19 is completely closed, and the end of the spiral conveying blade 18 away from the piston block 13 moves to the upper part of the buffer tube 19. Since the buffer tube 19 is located in front of the feed tube 7 relative to the material conveying direction inside the conveying cylinder 6, the material inside the conveying cylinder 6 will be discharged through the buffer tube 19 first, thereby slowing down the entry of the material into the feed tube 7. The bottom of the buffer tube 19 can be connected to a recycling box for recycling materials, so that the material discharged through the buffer tube 19 can be subsequently recycled and used. When the internal pressure of the feed tube 7 becomes smaller, under the action of the support rebound component, the piston block 13 is reset, thereby driving the isolation plate 20 and the spiral conveying blade 18 to reset. The isolation plate 20 is reset to the top of the buffer tube 19, and the buffer tube 19 is closed to prevent the material inside the conveying cylinder 6 from being sent out through the buffer tube 19. Through the above structure, the internal pressure of the feed tube can be avoided from being too high, and the conveying motor 8 can be prevented from being overloaded, thereby affecting its service life.

[0031] Example 2

[0032] Based on the above embodiments, see Figure 5 , Figure 6 As shown, a plurality of mounting grooves 21 are opened along the path of the inner walls on opposite sides of the slide groove 17, and a movable wheel 23 is rotatably arranged in the mounting groove 21 through a fixing pin 22. The wheel surface of the movable wheel 23 is away from the bottom of the mounting groove 21 and protrudes from the notch of the mounting groove 21. When in use, by setting the movable wheel 23, the wheel surface of the movable wheel 23 is slidably contacted with the side wall of the slide bar 16, thereby reducing the friction force of the sliding connection between the slide bar 16 and the slide groove 17, ensuring that when the transmission rod 12 drives the sleeve 11 to rotate, the sleeve 11 can slide smoothly along the transmission rod 12.

[0033] As a preferred embodiment, see Figure 5 , Figure 6As shown, two slide bars 16 and two slide grooves 17 are provided, the two slide bars 16 are symmetrically arranged on the outer wall of the transmission rod 12 with the axis of the transmission rod 12 as the axis of symmetry, and the two slide grooves 17 are symmetrically arranged on the inner wall of the sleeve 11 with the axis of the sleeve 11 as the axis of symmetry. When the sleeve 11 is sleeved on the outer side of the transmission rod 12, the two slide bars 16 respectively pass through the corresponding slide grooves 17 and are slidably connected with the slide grooves 17. By providing two slide bars 16 and two slide grooves 17, the uniformity of force between the transmission rod 12 and the sleeve 11 is ensured.

[0034] As a preferred embodiment, see Figure 4 As shown, a sealing strip 24 is provided at the opening of one end of the chute 17 away from the piston block 13 and the opening of the other end of the sleeve 11 away from the piston block 13. By providing the sealing strip 24, materials are prevented from entering the chute 17 and the sleeve 11.

[0035] Example 3

[0036] Based on the above embodiments, see Figure 2 , Figure 3 As shown, the support rebound assembly includes a support spring 25 and a support ring 26. The support ring 26 is movably sleeved on the outside of the transmission rod 12 and placed between the piston block 13 and the conveying motor 8. The inner ring diameter of the support ring 26 is larger than the sum of the outer ring diameter of the transmission rod 12 and the height of the slide bar 16 to ensure that the transmission rod 12 and the slide bar 16 can smoothly pass through the support ring 26. The support spring 25 is sleeved on the outside of the transmission rod 12. One end of the support spring 25 is fixedly connected to the piston block 13, and the other end is fixedly connected to the support ring 26. When in use, when the piston block 13 moves toward the conveying motor 8, the support spring 25 will be squeezed. The present invention utilizes the reset and pressure balance characteristics of the support spring 25, so that when the internal pressure of the feeding pipe 7 is relatively large, the piston block 13 moves to squeeze the support spring 25 to generate elastic potential energy. When the internal pressure of the feeding pipe 7 is reduced, the support spring 25 releases the elastic potential energy to reset and push the piston block 13 to move and reset, thereby ensuring subsequent normal conveying.

[0037] As a preferred embodiment, see Figure 1 , Figure 3As shown, two bar holes 27 connected to the interior of the conveying cylinder 6 are opened on the outer wall of one end close to the conveying motor 8, and the two bar holes 27 are symmetrically arranged on the outer wall of the conveying cylinder 6. Two screws 28 are connected to the support ring 26. The ends of the two screws 28 away from the support ring 26 pass through the two bar holes 27 respectively and are threadedly connected with nuts 29. The outer wall of the conveying cylinder 6 is provided with scale lines 30 parallel to the bar holes 27; through the design of the screws 28, the bar holes 27 and the nuts 29, it is convenient to adjust the support ring 26 to a fixed position inside the conveying cylinder 6, so that when the feeding pressure is too large, the support ring 26 can be adjusted to be fixed close to the conveying motor 8, so that the support spring 25 relaxes the pressure, so that the piston block 13 can move toward the conveying motor 8, and the method combined with the above-mentioned embodiment can reduce The pressure of the feed pipe 7, when the pressure is insufficient, the support ring 26 is adjusted to be fixed away from the conveying motor 8, so that the support spring 25 accumulates energy and increases pressure, so that the piston block 13 will not easily move toward the conveying motor 8, thereby ensuring continuous delivery of materials to the feed pipe 7. In actual operation, the best balance point is found through multiple attempts, and the position of the nut 29 and the scale line 30 are aligned, which is convenient for later debugging reference and easy to use. It should be noted that a limit block 33 is provided on the inner wall of the conveying cylinder 6 at the end of the bar hole 27 away from the conveying motor 8. The limit block 33 is used to limit the piston block 13, so that there is a maximum sliding distance for the piston block 13 to slide to the end of the conveying motor 8, thereby preventing the piston block 13 from sliding through the bar hole 27, so that the material in the conveying cylinder 6 is discharged through the bar hole 27.

[0038] As a preferred embodiment, see Figure 2 , Figure 3 As shown, a limiting ring 31 is fixedly sleeved on one end of the transmission rod 12 away from the conveying motor 8. By setting the limiting ring 31, the sleeve 11 can be limited to prevent the sleeve 11 from sliding along the transmission rod 12 and contacting the inner wall of the conveying cylinder 6. Although the present invention is described herein with reference to a plurality of illustrative embodiments of the present invention, it should be understood that a person skilled in the art can design many other modifications and implementations, which will fall within the scope and spirit of the principles disclosed in the present application. More specifically, within the scope of the present application, the drawings and the claims, a variety of modifications and improvements can be made to the components and / or layout of the subject combination layout. In addition to the deformation and improvement of the components and / or layout, other uses will also be obvious to a person skilled in the art.

Claims

1. A twin-screw extruder, comprising a drive motor (1), a frame (2), a gear box (3), an extrusion barrel (4), and a twin-screw disposed inside the extrusion barrel (4), characterized in that: A horizontally arranged conveying cylinder (6) is installed on the upper part of the frame (2) through a support frame (5); the bottom of the conveying cylinder (6) is connected to the feeding end of the extrusion cylinder (4) through a feeding pipe (7); a conveying motor (8) is provided on the end of the conveying cylinder (6) away from the feeding pipe (7); the output shaft of the conveying motor (8) rotates through a rotating hole (9) to penetrate into the interior of the conveying cylinder (6) and is transmission-connected to a feeding adjustment mechanism; a feeding hopper (10) is provided on the top of the conveying cylinder (6) and is connected to the interior of the conveying cylinder (6); The feeding adjustment mechanism comprises a sleeve (11), a transmission rod (12) and a piston block (13); the piston block (13) is slidably arranged inside the conveying cylinder (6); a support rebound component is arranged on the piston block (13); a movable hole penetrating through both sides of the piston block (13); a sealed bearing (14) is installed in the movable hole; one end of the transmission rod (12) is transmission-connected to the output shaft of the conveying motor (8); the other end of the transmission rod (12) is movable through the inner hole of the sealed bearing (14); The transmission rod (12) is provided with a sliding bar (16) parallel to the transmission rod (12); the sleeve (11) is sleeved on the outer side of the transmission rod (12); one end of the sleeve (11) is fixedly connected to the inner ring of the sealing bearing (14); a sliding groove (17) is provided on the inner wall of the sleeve (11) along its axis and passes through both ends; and a spiral conveying blade (18) is provided on the outer wall of the sleeve (11); When the sleeve (11) is sleeved on the outer side of the transmission rod (12), the slide bar (16) passes through the slide groove (17) and is slidably connected to the slide groove (17), and the length of the slide bar (16) is longer than the length of the sleeve (11); The bottom side of the conveying cylinder (6) is connected to a buffer tube (19), and the bottom of the piston block (13) away from the conveying motor (8) is connected to an isolation plate (20), and the isolation plate (20) is used to close the top of the buffer tube (19).

2. A twin-screw extruder according to claim 1, characterized in that: A plurality of mounting grooves (21) are provided along the path of the inner walls on opposite sides of the slide groove (17), and a movable wheel (23) is rotatably arranged in the mounting groove (21) via a fixing pin (22), and the wheel surface of the movable wheel (23) is away from the bottom of the mounting groove (21) and protrudes out of the notch of the mounting groove (21).

3. A twin-screw extruder according to claim 1, characterized in that: Two of the slide bars (16) and two of the slide grooves (17) are provided. The two slide bars (16) are symmetrically arranged on the outer wall of the transmission rod (12) with the axis of the transmission rod (12) as the axis of symmetry. The two slide grooves (17) are symmetrically arranged on the inner wall of the sleeve (11) with the axis of the sleeve (11) as the axis of symmetry.

4. A twin-screw extruder according to claim 1, characterized in that: A sealing strip (24) is provided at an opening of one end of the slide groove (17) away from the piston block (13) and at an opening of one end of the sleeve (11) away from the piston block (13).

5. A twin-screw extruder according to claim 1, characterized in that: The support and rebound assembly comprises a support spring (25) and a support ring (26); the support ring (26) is movably sleeved on the outside of the transmission rod (12) and is placed between the piston block (13) and the conveying motor (8); the support spring (25) is sleeved on the outside of the transmission rod (12); one end of the support spring (25) is fixedly connected to the piston block (13), and the other end is fixedly connected to the support ring (26).

6. A twin-screw extruder according to claim 5, characterized in that: Two strip holes (27) are provided on the outer wall of one end of the conveying cylinder (6) close to the conveying motor (8) and are connected to the interior of the conveying cylinder (6). The two strip holes (27) are symmetrically arranged on the outer wall of the conveying cylinder (6). Two screw rods (28) are connected to the support ring (26). The ends of the two screw rods (28) away from the support ring (26) respectively pass through the two strip holes (27) and are threadedly connected with nuts (29).

7. A twin-screw extruder according to claim 6, characterized in that: The outer wall of the conveying cylinder (6) is provided with a scale line (30) parallel to the strip hole (27).

8. A twin-screw extruder according to claim 1, characterized in that: A limiting ring (31) is fixedly sleeved on one end of the transmission rod (12) away from the conveying motor (8).

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