A PET conical co-rotating twin-screw extrusion granulator

Abstract

The application provides a PET conical corotating double-screw extrusion granulator, and belongs to the technical field of double-screw extrusion granulation, which comprises a conical screw, a positioning structure, a mounting piece, a constraint piece and an adjusting locking piece. The PET conical corotating double-screw extrusion granulator is characterized in that the positioning structure is arranged at the input end region and the output end region of the conical screw, and the abutting cooperation between the positioning structure and the inner wall of the inner cone cylinder is utilized to quickly establish the coaxial positioning state between the conical screw and the inner cone cylinder in the assembly stage; then the axial locking state is established by the constraint pieces at the input end and the output end, the axial adjustment reference is established later, the output end constraint piece is utilized to drive the conical screw to quantitatively retreat axially, the positioning structure is separated from the abutment with the inner cone cylinder, and the conical screw and the inner cone cylinder form a preset mounting gap, so that the problems of repeated detection, trial assembly and adjustment in the traditional assembly process are effectively avoided, the whole assembly flow line is simple, the assembly efficiency is high, and the dependence on manual experience is sufficiently reduced.

Description

Technical Field

[0001] This invention relates to the field of twin-screw extrusion granulation technology, specifically to a PET conical co-rotating twin-screw extruder granulator. Background Technology

[0002] The conical twin-screw extruder is a highly efficient mixing and extrusion equipment with advantages such as uniform plasticizing and mixing, high output, stable quality, and wide applicability. It can directly extrude various thermoplastic plastics, especially rigid polyvinyl chloride powder, and can also complete the modification and granulation processes of various plastics. Its application in the plastics processing industry is becoming increasingly widespread.

[0003] Existing conical co-rotating twin-screw extruders typically include a conical barrel and a conical twin-screw structure located inside the barrel. Since both the inner wall of the barrel and the outer circumference of the screw are conical, the precision of the gap between the screw and the barrel directly affects the stability of material conveying, the uniformity of plasticization, and the service life of the equipment. Therefore, high requirements are placed on the coaxiality and gap consistency between the screw and the barrel.

[0004] However, in the existing equipment, during the screw installation process, it is usually necessary to repeatedly check the radial clearance between the screw and the barrel, and adjust the screw position by means of external tooling, shim adjustment, or repeated trial installation to keep the screw and the barrel coaxial and form a predetermined working clearance. The entire installation process is not only cumbersome and time-consuming, but also heavily dependent on the experience and technical level of the operators.

[0005] Therefore, optimizing the structure of the conical twin-screw extruder to simplify its assembly process, improve assembly efficiency, and reduce reliance on manual experience has significant practical engineering value. Summary of the Invention

[0006] This invention provides a PET conical co-directional twin-screw extruder granulator, comprising a base, two conical screws, a positioning structure, a mounting component, a constraint component, and an adjusting locking component. The base has two interconnected inner conical cylinders. The larger diameter end of the conical screw is the input end, and the smaller diameter end is the output end. The conical screws are respectively disposed in the inner conical cylinders and are coaxial with the corresponding inner conical cylinders with a gap distribution. The positioning structure is disposed in the input and output end regions of the conical screws. In the assembled state, the positioning structure abuts against the inner wall of the inner conical cylinder, keeping the conical screws and inner conical cylinders coaxial. The mounting component is disposed at the input and output ends of the base. The constraint component is axially slidably disposed on the mounting component, and the constraint component is positioned between the conical screws and the inner conical cylinders. An axial limiting fit and a radial support fit are formed, allowing the tapered screw to rotate relative to the constraint member. An adjusting locking member is used to drive the constraint member to slide axially and lock its position. Specifically, the constraint member at the input end axially abuts against the tapered screw, causing the positioning structure to abut against the inner cone, establishing a coaxial positioning state. After the coaxial positioning state is established, the constraint member at the output end abuts against the tapered screw, forming an axial adjustment reference. After the axial adjustment reference is established, the constraint member at the input end releases its axial abutment against the tapered screw, and the constraint member at the output end moves a preset distance towards the input end to drive the tapered screw to move axially, causing the positioning structure to disengage from the inner cone and forming a preset installation gap between the tapered screw and the inner cone.

[0007] In one possible implementation, the positioning structure includes a mounting base and a plurality of positioning blocks distributed circumferentially on the mounting base, which is detachably mounted on a tapered screw.

[0008] In one possible implementation, the region of the conical screw near the output end is a homogenization section, the positioning block in the positioning structure at the output end is a spiral segment with the same spiral structure as the homogenization section, and the gap between the spiral segment and the inner cone is smaller than the gap between the conical screw and the inner cone.

[0009] In one possible implementation, the mounting member is fixedly installed on the base after the tapered screw is inserted into the inner tapered cylinder and the positioning structure abuts against the inner tapered cylinder, and the constraint member forms a supporting engagement with the tapered screw in the radial direction.

[0010] In one possible implementation, the tapered screw is provided with a stepped surface, and the constraint member is provided with a limiting surface corresponding to the stepped surface, the limiting surface and the stepped surface together forming an axial limiting fit.

[0011] In one possible implementation, the adjusting locking element is an adjusting screw threaded onto the mounting component, which achieves axial feeding and locking by tightening.

[0012] In one possible implementation, the constraint includes a support limiting sleeve and a sliding part, the sliding part being slidably disposed on the mounting member, and the support limiting sleeve being rotatably mounted on the sliding part.

[0013] In one possible implementation, the mounting component is provided with a guide structure for the constraint component to slide, the guide structure being a guide groove.

[0014] The above-mentioned one or more technical solutions in the embodiments of the present invention have the following technical effects: According to the embodiments of the present invention, a PET conical co-rotating twin-screw extruder granulator is provided by setting positioning structures in the input and output regions of the conical screw, and using the abutment fit between the positioning structures and the inner wall of the inner cone, a coaxial positioning state between the conical screw and the inner cone is quickly established during the assembly stage; subsequently, an axial locking state is first established by the constraint members at the input and output ends, and then an axial adjustment reference is established. The output end constraint members drive the conical screw to quantitatively axially retract, so that the positioning structure disengages from the inner cone. At the same time, the corresponding relationship between the axial displacement and radial clearance of the conical structure is used to automatically form a preset installation gap, thereby effectively avoiding the problems of repeated testing, trial assembly and adjustment in the traditional assembly process. The entire assembly flow is simple, the assembly efficiency is high, and the reliance on manual experience is greatly reduced.

[0015] Furthermore, the positioning structure in this invention only participates in centering during the assembly stage and disengages from the inner cone during normal operation. Therefore, it does not participate in continuous friction support during operation, which can effectively avoid the wear, local heating and thermal expansion jamming problems of traditional long-term contact guide structures, and is conducive to improving the operational stability and service life of the equipment. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the base, inner cone, and conical screw of a PET conical co-rotating twin-screw extruder provided in an embodiment of the present invention;

[0017] Figure 2 This is a schematic diagram of the output end mounting component, sliding part, and positioning block of a PET conical co-rotating twin-screw extruder provided in an embodiment of the present invention;

[0018] Figure 3 This is a schematic diagram of the input end mounting component, sliding part, and positioning block of a PET conical co-rotating twin-screw extruder provided in an embodiment of the present invention.

[0019] In the figure: 1. Base; 2. Inner cone cylinder; 3. Conical screw; 4. Positioning structure; 41. Assembly seat; 42. Positioning block; 5. Mounting component; 6. Constraint component; 61. Support and limit sleeve; 62. Sliding part; 7. Adjusting and locking component. Detailed Implementation

[0020] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described below, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0021] Please see Figures 1-3 A PET conical co-rotating twin-screw extruder granulator includes a base 1, an inner cone 2, a conical screw 3, a positioning structure 4, a mounting component 5, a constraint component 6, an adjusting locking component 7, a drive mechanism (not shown in the figure), and an extrusion head (not shown in the figure).

[0022] like Figure 1 As shown, the base 1 has two interconnected inner conical cylinders 2, which are integrally formed. Each inner conical cylinder 2 has a tapered hole structure with a smaller diameter at the left end and a larger diameter at the right end; the larger diameter end is the input end, and the smaller diameter end is the output end. Two conical screws 3 are installed in the inner conical cylinders 2. The base 1 also has a heating system and a feed inlet (not shown in the figure) near the top of the input end. A feeding mechanism is installed at the feed inlet to feed the material into the inner conical cylinders 2. The material is then conveyed from right to left by the two conical screws 3 rotating in the same direction. Combined with the heating from the heating system, the material is mixed and melted during the conveying process.

[0023] During assembly, the conical screw 3 is inserted into the corresponding inner conical cylinder 2 from right to left, coaxial with the inner conical cylinder 2 and with a gap distribution. The right end of the conical screw 3 is the large-diameter end, and the left end is the small-diameter end. The large-diameter end is the input end and is connected to the external drive mechanism, while the small-diameter end is the output end, where an extrusion head (not shown in the figure) is installed. The taper of the conical screw 3 matches the taper of the inner conical cylinder 2. The conical screw 3 includes a central shaft and, from right to left, a feeding section, a melting section, a venting section, and a homogenizing section. The feeding section, melting section, venting section, and homogenizing section are all modular structures that can be detachably installed on the central shaft, and the structures of the feeding section, melting section, venting section, and homogenizing section are all existing technologies.

[0024] Positioning structures 4 are respectively disposed in the input end region (near the input end) and output end region (near the output end) of each conical screw 3. Positioning structure 4 includes a mounting base 41 and several positioning blocks 42, with 3-6 positioning blocks 42 distributed circumferentially on the mounting base 41. The positioning blocks 42 in the positioning structures 4 at the same end of the two conical screws 3 are staggered axially or circumferentially to avoid interference between the two conical screws 3 during synchronous rotation. The mounting base 41 is detachably mounted on the conical screw 3. The positioning block 42 in the positioning structure 4 at the output end is a helical segment identical to the homogenizing section helical structure. The gap between the helical segment and the inner conical cylinder 2 is smaller than the gap between the conical screw 3 and the inner conical cylinder 2, ensuring that the conical screw 3 does not come into contact with the inner wall of the inner conical cylinder 2 when its helical end abuts against the inner wall. Specifically, during assembly, as the conical screw 3 is inserted into the inner conical cylinder 2, the positioning block 42 abuts against the inner wall of the inner conical cylinder 2 before the conical screw 3 contacts the inner wall of the inner conical cylinder 2. This positioning block positions the conical screw 3 according to the position of the inner conical cylinder 2, ensuring they remain coaxial. Similarly, the positioning structure 4 at the input end also abuts against the inner wall of the inner conical cylinder 2, positioning the conical screw 3 according to the position of the inner conical cylinder 2, ensuring they remain coaxial. This creates positioning points at the front and rear ends of the conical screw 3, stably maintaining the coaxiality between the conical screw 3 and the inner conical cylinder 2. The positioning block 42 in the positioning structure 4 at the input end is an arc-shaped conical block. Its conical surface abuts against the inner conical surface of the inner conical cylinder 2. The arc-shaped conical surface is located on the right side of the feed inlet, so it does not affect the feeding process. Simultaneously, it increases the contact area between the positioning block 42 and the inner wall of the inner conical cylinder 2, further improving the stability of the positioning process. Of course, the input end positioning block 42 can also be set as a spiral segment corresponding to the spiral structure of the feeding section, and the gap between the spiral segment and the inner cone 2 is also set to be smaller than the gap between the conical screw 3 and the inner cone 2. During the assembly process, the corresponding positioning block 42 also abuts against the inner wall of the inner cone 2 before the conical screw 3 contacts the inner wall of the inner cone 2.

[0025] See Figures 1-3Mounting element 5 is located at the input and output ends of the base 1. Specifically, mounting element 5 is an end cap, which is fixedly and sealed to both ends of the base 1 by bolts. Constraint element 6 is slidably mounted on mounting element 5 along the axial direction. Specifically, constraint element 6 is a combined structure, including a support limiting sleeve 61 and a sliding part 62. Mounting element 5 has a guide groove for mounting the sliding part 62; the guide groove is a guide structure, and the outer surface of the sliding part 62 forms a sliding fit with the guide groove, allowing the sliding part 62 to move axially. The support limiting sleeve 61 is rotatably mounted on the sliding part 62 via a set of angular contact ball bearings (not shown in the figure). The inner hole of the support limiting sleeve 61 forms a radial support fit with the journal of the tapered screw 3, while its end face forms an axial limiting fit with the shoulder on the tapered screw 3. This allows the tapered screw 3 to rotate freely relative to constraint element 6, but its radial and axial positions are constrained.

[0026] See Figures 1-3 The adjusting locking element 7 is used to drive the constraint element 6 to slide axially and lock its position. Specifically, the adjusting locking element 7 is an adjusting screw threaded onto the mounting part 5. Specifically, a threaded hole is machined on the side of the mounting part 5, and the adjusting locking element 7 is screwed into the threaded hole, with its front end abutting against the outer end face of the sliding part 62 of the constraint element 6. By turning the adjusting locking element 7, the constraint element 6 can be pushed to move towards the inside of the machine body (input end direction or output end direction); when turned in the opposite direction to loosen it, the constraint element 6 can be retracted under the action of external force. Specifically, there are at least three adjusting locking elements 7 on each mounting part 5. One is located in the middle, and the other two are located on both sides, wherein the middle one is used for adjustment, and the two side ones are used for further locking after adjustment.

[0027] The following describes the dynamic mating logic of the present invention in conjunction with the installation process: Step 1: Establishing a coaxial positioning state. Push the two tapered screws 3 into the corresponding inner tapered cylinders 2 from the input end until the positioning structures 4 at the front and rear ends of the tapered screws 3 abut against the inner tapered surface of the inner tapered cylinder 2. Then install the mounting part 5 at the output end. Here, when the support limiting sleeve 61 and the sliding part 62 are pre-assembled together, they are also pre-set to be assembled together with the mounting part 5. During the installation of the mounting part 5, first align the support limiting sleeve 61 with the tapered screws 3 and put it on the end of the tapered screws 3 until the mounting part 5 abuts against the base 1. Then use fasteners to fix the mounting part 5 and the base 1 together. Subsequently, screw the adjusting locking part 7 located at the input end. Through the axial limiting surface of the constraint part 6 contacting and abutting the stepped surface of the tapered screws 3, the positioning structure 4 is pressed against the inner tapered surface of the inner tapered cylinder 2. At this time, the two tapered screws 3 are locked in a position coaxial with the inner tapered cylinder 2.

[0028] Step 2: Establish the axial adjustment reference. While maintaining the coaxial positioning described above, install the mounting piece 5 at the input end (including the pre-assembled constraint piece 6). Then, tighten the adjusting locking piece 7 at the output end, causing it to push the constraint piece 6 at the output end towards the input end, until the axial limiting surface of the constraint piece 6 at the output end also abuts against the stepped surface of the tapered screw 3. Here, the stepped surface of the tapered screw 3 is the end face of the tapered structure. At this point, the position of the constraint piece 6 at the output end is the axial adjustment reference.

[0029] Step 3: Release the input constraint and precisely retract. Keeping the output adjusting locking member 7 stationary, loosen the input adjusting locking member 7 in the opposite direction, releasing the input constraint member 6 from its axial clamping position on the conical screw 3. At this point, the conical screw 3 is only axially positioned by the output constraint member 6. Continue to slowly tighten the output adjusting locking member 7 (e.g., 1 / 4 turn each time), causing it to push the output constraint member 6 a preset distance towards the input. Due to the axial limiting engagement between the output constraint member 6 and the conical screw 3, the conical screw 3 will move synchronously towards the input following the constraint member 6. This movement causes the originally tightly abutting positioning structure 4 to disengage from the inner conical surface of the inner conical cylinder 2, preventing jamming due to thermal expansion during subsequent operation. After the positioning structure 4 disengages from the inner conical cylinder 2, the radial position of the conical screw 3 is jointly supported and limited by the input and output constraint members 6, maintaining the coaxial state between the conical screw 3 and the inner conical cylinder 2. Since the positioning structure 4 has already aligned the conical screw 3 during the assembly stage, it is only necessary to maintain the predetermined axial position using the constraint member 6. Simultaneously, the working clearance between the conical screw 3 and the inner conical cylinder 2 reaches the preset installation clearance. Because the taper parameters of the inner conical cylinder 2 and the conical screw 3 are fixed, there is a definite correspondence between the axial movement of the conical screw 3 and the radial clearance change. Those skilled in the art can determine the axial adjustment amount of the constraint member 6 based on the target installation clearance. Furthermore, based on the axial adjustment mechanism of this invention, the clearance between the conical screw 3 and the inner conical cylinder 2 can be precisely set. Precise control of the clearance improves the stability of the shearing state during melt conveying, effectively avoiding material backflow and ineffective shearing due to excessive clearance, or additional shearing power consumption and localized overheating due to insufficient clearance. This helps reduce drive energy consumption and achieve energy saving, improving plasticizing quality. Since the spiral structure of the output end positioning block 42 is aligned with the material conveying direction, it does not obstruct material flow or create dead zones.

[0030] It should be noted that, in this invention, during installation, the positioning block 42 contacts the inner wall of the inner cone cylinder 2 before the tapered screw 3. At this time, a small gap remains between the tapered screw 3 and the inner cone cylinder 2 (this gap is smaller than the preset installation gap). Subsequently, the tapered screw 3 is precisely retracted by adjusting the locking component 7 at the output end, causing the positioning block 42 to separate from the inner wall of the inner cone cylinder 2. Simultaneously, the gap between the tapered screw 3 and the inner cone cylinder 2 reaches the preset installation gap (0.05mm to 0.08mm). Since the adjusting locking component uses threaded transmission (pitch 1.0 to 1.5mm), micron-level feed can be achieved by controlling the rotation angle. Furthermore, the separation gap between the positioning block 42 and the inner cone cylinder 2 during the retraction process (≥0.02mm) is much larger than the thermal expansion. Therefore, this adjustment process is precise, controllable, and repeatable. In addition, the processing accuracy of existing technologies can fully meet the requirements of this invention. Specifically, the roundness of the inner bore of the high-performance extruder's inner cone 2 can reach 0.01mm, and the straightness of the axis meets grade 7 accuracy (GB / T 1184). The screw's outer diameter accuracy reaches grade 8, with a straightness of 0.015mm and coaxiality better than 0.02mm. The thread element length tolerance is ±0.01mm, far exceeding the 0.02mm gap control of the positioning block 42 and the 0.05-0.08mm working gap requirements required by this invention. Supported by standards such as JB / T 8538 and JB / T 6492, the manufacturing precision of the relevant components is sufficient to ensure the accurate implementation of the forced centering and retraction separation of the positioning structure.

[0031] After completing the above adjustments, tighten the locking nuts on all adjusting locking parts 7. Then, connect the drive mechanism to the input end of the conical screw 3 located outside the inner conical cylinder 2. The specific drive mechanism includes a motor, a transmission box, and a spline sleeve. The input end of the conical screw 3 is connected to the transmission box through the spline sleeve. The motor drives the two conical screws 3 to rotate in the same direction through the transmission box. Install the extrusion head on the output end of the conical screw 3. The inner conical cylinder 2 has a radial discharge port (not shown in the figure). The inlet of the extrusion head and the radial discharge port are sealed together. The material enters the extrusion head through the discharge port-inlet and is then extruded and formed.

[0032] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0033] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "connected," "installed," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, an integral connection, or a sliding connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made based on the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A PET conical co-rotating twin-screw extruder granulator, characterized in that: It includes a base having two interconnected inner conical cylinders; Two conical screws, the large-diameter end of the conical screws is the input end and the small-diameter end is the output end, and the conical screws are respectively arranged in the inner conical cylinders, and are coaxial with the corresponding inner conical cylinders and have gap distribution; A positioning structure is provided in the input and output regions of the tapered screw. In the assembled state, the positioning structure abuts against the inner wall of the inner tapered cylinder, so that the tapered screw and the inner tapered cylinder remain coaxial. Mounting components are installed at the input and output ends of the base; The constraint component is axially slidably mounted on the mounting component, and the constraint component and the tapered screw form an axial limiting fit and a radial support fit, allowing the tapered screw to rotate relative to the constraint component; Adjust the locking mechanism to drive the constraint component to slide axially and lock its position; Among them, the constraint member located at the input end axially abuts against the tapered screw, so that the positioning structure abuts against the inner tapered cylinder and establishes a coaxial positioning state; After the constraint at the output end is established in the coaxial positioning state, it abuts against the tapered screw to form an axial adjustment reference; The positioning structure includes an assembly base and several positioning blocks. The positioning blocks are distributed circumferentially on the assembly base, and the assembly base is detachably mounted on the tapered screw. After the axial adjustment reference is established, the constraint at the input end releases its axial clamping on the conical screw, and the constraint at the output end moves a preset distance toward the input end to drive the conical screw to move axially, so that the positioning structure disengages from the inner conical cylinder and a preset installation gap is formed between the conical screw and the inner conical cylinder.

2. The PET conical co-rotating twin-screw extruder granulator according to claim 1, characterized in that: The area of ​​the conical screw near the output end is the homogenization section. The positioning block in the positioning structure at the output end is a spiral segment with the same spiral structure as the homogenization section, and the gap between the spiral segment and the inner cone is smaller than the gap between the conical screw and the inner cone.

3. A PET conical co-rotating twin-screw extruder granulator according to claim 1, characterized in that: The mounting component is fixedly installed on the base after the tapered screw is placed inside the inner tapered cylinder and the positioning structure abuts against the inner tapered cylinder, and the constraint component forms a supporting fit with the tapered screw in the radial direction.

4. A PET conical co-rotating twin-screw extruder granulator according to claim 1, characterized in that: The tapered screw has a stepped surface, and the constraint member has a limiting surface corresponding to the stepped surface. The limiting surface and the stepped surface together form an axial limiting fit.

5. A PET conical co-rotating twin-screw extruder granulator according to claim 1, characterized in that: The adjusting locking component is an adjusting screw threaded onto the mounting component, which achieves axial feeding and locking by tightening.

6. A PET conical co-rotating twin-screw extruder granulator according to claim 1 or 4, characterized in that: The constraint component includes a support limiting sleeve and a sliding part. The sliding part is slidably disposed on the mounting component, and the support limiting sleeve is rotatably mounted on the sliding part.

7. A PET conical co-rotating twin-screw extruder granulator according to claim 1, characterized in that: The mounting component is provided with a guide structure for the constraint component to slide, and the guide structure is a guide groove.

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