Production device and production method of polyethylene composite pipe

Abstract

The application discloses a polyethylene composite pipe production device and a production method. The production device comprises a distribution joint assembly, an outer die, an inner sleeve arranged in the outer die, a core die arranged in the inner sleeve, and an inner layer extrusion structure connected with the core die; an annular outer layer flow channel for extruding an outer layer of the polyethylene composite pipe is formed between the outer die and the inner sleeve, an annular feeding channel is formed between the inner sleeve and the core die, an extrusion flow channel is arranged in the core die, the distribution joint assembly is in communication with the outer layer flow channel and the extrusion flow channel respectively, and the inner layer extrusion structure is in communication with the extrusion flow channel. The chopped basalt fiber and calcium carbonate powder mixture can be sprayed on the extruded polyethylene pipe outer layer to form a reinforcing layer, so that the radial stiffness of the polyethylene composite pipe is improved. The outer layer, the reinforcing layer and the inner layer of the polyethylene composite pipe can be formed at one time, and the production efficiency is improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of polyethylene composite pipe production, and discloses a polyethylene composite pipe production device and a production method. BACKGROUND

[0002] At present, polyethylene composite pipes have been widely applied in various industries, and with the gradual expansion of urban construction, polyethylene pipes will also be used in more severe environments, therefore, the performance requirements for polyethylene composite pipes are higher and higher. In order to improve the strength of polyethylene composite pipes, some technologies will wrap continuous reinforcing fibers on the embryo pipe of the polyethylene composite pipe during the production of the polyethylene composite pipe, so that the axial strength of the polyethylene composite pipe can be improved, but the radial rigidity of the polyethylene composite pipe still cannot meet the requirements of some severe environments. Therefore, the application provides a polyethylene composite pipe production device and a production method, which can improve the rigidity of the polyethylene composite pipe by spraying a reinforcing layer on the pipe. SUMMARY

[0003] The application aims to solve the above problems and provides a polyethylene composite pipe production device and a production method, which can improve the rigidity of the polyethylene composite pipe by spraying a reinforcing layer on the pipe.

[0004] The application is achieved by the following technical scheme: a polyethylene composite pipe production device, which comprises a distribution joint assembly, an outer die, an inner sleeve arranged in the inner part of the outer die, a core die arranged in the inner part of the inner sleeve, and an inner layer extrusion structure connected with the core die; an annular outer layer flow channel for extruding the outer layer of the polyethylene composite pipe is formed between the outer die and the inner sleeve, an annular feeding channel is formed between the inner sleeve and the core die, an extrusion flow channel is arranged in the core die, the distribution joint assembly is in communication with the outer layer flow channel and the extrusion flow channel respectively, and the inner layer extrusion structure is in communication with the extrusion flow channel.

[0005] Further, a guide plate is arranged on the end face of the extrusion end of the core die; the guide plate is annularly arranged around the periphery of the extrusion flow channel; the end of the guide plate away from the core die is outwardly bent and extends to the outlet of the feeding channel, so that the cross section of the guide plate is in the shape of a circular arc, and the material blown out from the feeding channel is guided to the inner wall of the outer layer of the polyethylene composite pipe.

[0006] An annular glue spraying pipe is mounted on the end part of the extrusion end of the inner sleeve, and a plurality of glue spraying openings towards the outer layer of the polyethylene composite pipe are uniformly arranged on the glue spraying pipe.

[0007] The production device of the polyethylene composite pipe further comprises a distribution cover; the distribution cover is bolted on one end of the core mold away from the extrusion end, and the distribution cover forms a distribution cavity with the outer die, the inner sleeve and the core mold, and the feeding channel communicates with the distribution cavity.

[0008] The height of the outer layer runner gradually increases from the feeding end to the extrusion end, and the outer wall of the inner sleeve is provided with a spiral runner which gradually becomes shallower from the feeding end to the discharging end.

[0009] The distribution joint assembly comprises a distribution joint, a first distribution pipe and a second distribution pipe connected with the distribution joint respectively, and a stop valve arranged on the second distribution pipe; the distribution joint is provided with a feeding port, and a first distribution channel and a second distribution channel which respectively communicate with the feeding port; the first distribution pipe communicates with the first distribution channel, and the second distribution pipe communicates with the second distribution channel; the first distribution pipe communicates with the spiral runner after penetrating through the side wall of the outer die, and the second distribution pipe communicates with the extrusion runner after penetrating through the side wall of the outer die and the inner sleeve.

[0010] The inner layer extrusion structure comprises a horn-shaped inner die and a conical distribution shuttle; the inner die is installed on the end face of the extrusion end of the core mold through an installation plate, and the distribution shuttle is fixed in the inner die through an installation rod; the inner die and the distribution shuttle form a ring-shaped inner layer runner which extends to the outer layer of the polyethylene composite pipe and communicates with the extrusion runner; the distal ends of the inner die and the distribution shuttle are close to the outer layer of the polyethylene composite pipe, so that a storage cavity which communicates with the ring-shaped inner layer runner is formed among the outer layer of the polyethylene composite pipe, the inner die and the distribution shuttle; the distal end of the distribution shuttle is provided with a horizontal extension part which forms an extrusion gap which communicates with the storage cavity between the horizontal extension part and the outer layer of the polyethylene composite pipe.

[0011] The distribution shuttle is connected with a compression ring for extruding the inner layer of the polyethylene composite pipe through a support rod.

[0012] A production method of a polyethylene composite pipe, which adopts the production device of the polyethylene composite pipe described above, and specifically comprises the following steps:

[0013] Step 1: Close the stop valve, and extrude the outer layer of the polyethylene composite pipe after the molten polyethylene raw material passes through the first distribution channel, the first distribution pipe, the spiral runner and the outer layer runner;

[0014] Step 2: when the outer layer of the polyethylene composite pipe is extruded, the adhesive is supplied to the glue spraying pipe to uniformly spray the adhesive on the inner wall of the outer layer of the polyethylene composite pipe; meanwhile, the mixture of the chopped basalt fiber and the calcium carbonate powder is blown into the distribution cavity, and the mixture of the chopped basalt fiber and the calcium carbonate powder is uniformly adhered to the inner wall of the outer layer of the polyethylene composite pipe after passing through the feeding channel and the guide plate to form a reinforcing layer;

[0015] Step 3: when the front end of the outer layer of the polyethylene composite pipe moves to the corresponding position at the end of the inner die, the stop valve is opened, and the molten polyethylene raw material passes through the second distribution channel, the second distribution pipe, the extrusion flow channel and the annular inner layer flow channel to be coated on the inner side of the reinforcing layer by the horizontal extension to form the inner layer of the polyethylene composite pipe;

[0016] Step 4: the inner layer of the polyethylene composite pipe is compressed by the compression ring to form a pipe blank;

[0017] Step 5: after the pipe blank is shaped, cooled and cut, the polyethylene composite pipe is obtained.

[0018] Further, the weight ratio of the chopped basalt fiber and the calcium carbonate powder is 1:1, the length of the chopped basalt fiber is 1-2 mm, and the particle size of the calcium carbonate powder is 50-100 nm.

[0019] Compared with the prior art, the application has the following beneficial effects: the feeding channel and the guide plate are arranged to spray the mixture of the chopped basalt fiber and the calcium carbonate powder on the outer layer of the extruded polyethylene pipe to form a reinforcing layer, so as to improve the radial stiffness of the polyethylene composite pipe. The outer layer, the reinforcing layer and the inner layer of the polyethylene composite pipe can be formed at one time, and the production efficiency is improved.

[0020] Some of the additional features of the present application can be explained in the following description. Some of the additional features of the present application will be apparent to those skilled in the art upon examination of the following description or can be learned by practice or use of the following examples. The features disclosed by the present application can be realized and attained by means of the instruments, methods and combinations particularly pointed out in the following description. BRIEF DESCRIPTION OF DRAWINGS

[0021] The drawings described herein are intended to provide a further understanding of the present application, and constitute a part of the present application. The schematic embodiments of the present application and the description thereof are used to explain the present application, and do not constitute a limitation on the present application. In the drawings, the same reference numerals represent the same components. Among them,

[0022] Figure 1 is a sectional view of the present application.

[0023] Figure 2 is Figure 1 is an enlarged schematic view of A in FIG. 2.

[0024] Figure 3 Figure 1 is a cross-sectional view of the outer die and the inner sleeve of the present application.

[0025] Figure 4 Figure 2 is a cross-sectional view of the outer die and the inner sleeve of the present application. Figure 1 Figure 3 is an enlarged view of the area B in Figure 2.

[0026] In the above-mentioned figures, the reference numerals are as follows: 1 - dispensing joint, 2 - material injection port, 3 - first dispensing channel, 4 - second dispensing channel, 5 - first dispensing pipe, 6 - second dispensing pipe, 7 - shut-off valve, 8 - outer die, 9 - inner sleeve, 10 - feeding channel, 11 - core die, 12 - dispensing cavity, 13 - dispensing cover, 14 - material inlet runner, 15 - extrusion runner, 16 - mounting plate, 17 - mounting rod, 18 - inner die, 19 - annular inner layer runner, 20 - distribution shuttle, 21 - compression ring, 22 - support rod, 23 - polyethylene composite pipe outer layer, 24 - horizontal extension, 25 - storage cavity, 26 - extrusion gap, 27 - helical runner, 28 - outer layer runner, 29 - guide plate, 30 - glue injection pipe. DETAILED DESCRIPTION

[0027] In order to make the personnel in the art better understand the scheme of the present application, the technical scheme in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person of ordinary skill in the art without making creative labor should belong to the protection scope of the present application.

[0028] It should be noted that if the terms "first", "second", and the like are involved in the specification and claims of the present application and the above-mentioned drawings, they are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, if the terms "include" and "have" and any variations thereof are involved, it is intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to the clearly listed steps or units, but can include other steps or units not clearly listed or inherent to the process, method, product or device.

[0029] In this application, when terms such as "upper," "lower," "left," "right," "front," "back," "top," "bottom," "inside," "outside," "center," "vertical," "horizontal," "transverse," and "longitudinal" are used, the orientations or positional relationships they indicate are based on the orientations or positional relationships shown in the accompanying drawings. These terms are primarily intended to better describe this application and its embodiments and are not intended to limit the devices, elements, or components indicated to having a specific orientation, or to being constructed or operated in a specific orientation.

[0030] Furthermore, some of the above terms may be used to express other meanings besides indicating a position or location. For example, the term "on" may also be used to indicate a dependency or connection in certain circumstances. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0031] Furthermore, in this application, the terms "installed," "disposed," "provided with," "connected," "connected," and "socketed" should be interpreted broadly. For example, they can refer to fixed connections, removable connections, or integral structures; mechanical connections or electrical connections; direct connections, indirect connections through an intermediary, or internal communication between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0032] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0033] Example

[0034] like Figure 1 As shown, this embodiment discloses a production device for a polyethylene composite pipe, which includes a distribution joint assembly, an outer die 8, an inner sleeve 9, a core die 11, an inner layer extrusion structure and a distribution outer cover 13.

[0035] Specifically, such as Figure 3 As shown, the inner sleeve 9 is sleeved inside the outer die 8. One end of the inner sleeve 9 is the extrusion end, and the other end is the feed end. The outer diameter of the inner sleeve 9 gradually decreases from the feed end to the extrusion end. Therefore, an annular outer layer flow channel 28 for extruding the outer layer 23 of the polyethylene composite pipe is formed between the inner sleeve 9 and the inner wall of the outer die 8. The outer layer flow channel 28 extends toward the extrusion end, and its width gradually increases from the feed end to the extrusion end. The feed end of the inner sleeve 9 is fitted with the outer die 8, so that the outer layer flow channel 28 is terminated at the feed end, preventing the material in the outer layer flow channel 28 from flowing out of the feed end. In addition, the outer wall of the feed end of the inner sleeve 9 is provided with a spiral flow channel 27, which gradually becomes shallower from its feed end to its discharge end.

[0036] Through the above structure, when the molten polyethylene raw material is extruded into the spiral flow channel 27, the polyethylene raw material flows along the outer flow channel 28 and the spiral flow channel 27 to the extrusion end at the same time. As the polyethylene raw material continuously flows forward, the spiral flow channel 27 gradually becomes shallower, and the polyethylene raw material in the spiral flow channel 27 continuously enters the outer flow channel 28 and finally flows along the outer flow channel 28 only, so that the polyethylene raw material uniformly fills the outer flow channel 28, and is finally extruded from the outer flow channel 28 to form the polyethylene composite pipe outer layer 23.

[0037] The core die 11 is arranged inside the inner sleeve 9 and coaxial with the inner sleeve 9. The annular feeding channel 10 is formed between the core die 11 and the inner sleeve 9. Similarly, the core die 11 is also divided into a feeding end and an extrusion end, and the distribution outer cover 13 is fixedly installed on the feeding end of the core die 11 by bolts, while the feeding end of the inner sleeve 9 and the outer mouth die 8 can be fixed with the distribution outer cover 13 by bolts. The distribution outer cover 13 forms a distribution cavity 12 with the feeding end of the outer mouth die 8, the inner sleeve 9 and the core die 11, and the feeding channel 10 communicates with the distribution cavity 12. The distribution outer cover 13 is provided with a feeding port which communicates with an external feeding pipe, and a fan can be arranged on the feeding pipe to blow the mixture of chopped basalt fibers and calcium carbonate powder into the distribution cavity 12, and then uniformly distribute it into the feeding channel 10 so that the mixture flows along the feeding channel 10.

[0038] In addition, as shown in Figure 4 the end face of the extrusion end of the core die 11 is provided with a guide plate 29 fixed by bolts. The guide plate 29 is annular, and the end of the guide plate 29 away from the core die 11 is bent outward and extends to the outlet of the feeding channel 10. That is, the cross section of the guide plate 29 is in the shape of a circular arc. When the mixture of chopped basalt fibers and calcium carbonate powder is blown out of the feeding channel 10, the mixture is guided and blocked by the guide plate 29 and flows outward, so as to be guided to the inner wall of the just extruded polyethylene composite pipe outer layer 23.

[0039] In addition, the end of the extrusion end of the inner sleeve 9 is fixed with an annular glue injection pipe 30, and the glue injection pipe 30 is uniformly provided with a plurality of glue injection ports facing the polyethylene composite pipe outer layer 23. When specifically arranged, the glue inlet head of the glue injection pipe 30 extends into the feeding channel 10, and after passing through the inner sleeve 9 and the outer mouth die 8 from the feeding channel 10, it is connected to an external glue injection machine. Since the diameter of the glue inlet head of the glue injection pipe 30 is small, it will not affect the flow of materials inside the feeding channel 10 and the outer flow channel 28 when it passes through the feeding channel 10 and the outer flow channel 28, nor will it affect the normal production of the equipment.

[0040] When the glue injection machine injects glue into the glue injection pipe 30, the glue is evenly sprayed from the glue injection port to the inner wall of the just-extruded polyethylene composite pipe outer layer 23, so that when the mixture of chopped basalt fibers and calcium carbonate powder is blown onto the inner wall of the polyethylene composite pipe outer layer 23, it is adhered to the inner wall of the polyethylene composite pipe outer layer 23 to form a reinforcing layer.

[0041] The core mold 11 is horizontally provided with an extrusion flow channel 15 at the center position inside the core mold 11, and the guide plate 29 is arranged around the periphery of the outlet of the extrusion flow channel 15. The core mold 11 is also provided with an inclined material inlet flow channel 14, which is in communication with the extrusion flow channel 15.

[0042] The distribution joint assembly is in communication with the outer layer flow channel 28 and the extrusion flow channel 15, respectively. Specifically, the distribution joint assembly comprises a distribution joint 1, a first distribution pipe 5 and a second distribution pipe 6 connected to the distribution joint 1, respectively, and a stop valve 7 arranged on the second distribution pipe 6.

[0043] The distribution joint 1 is provided with a material injection port 2, and the inside of the distribution joint 1 is provided with a first distribution channel 3 and a second distribution channel 4 in communication with the material injection port 2, respectively. The first distribution pipe 5 is in communication with the first distribution channel 3, and the second distribution pipe 6 is in communication with the second distribution channel 4. The first distribution pipe 5 penetrates the side wall of the outer die 8 and is in communication with the spiral flow channel 27, and the second distribution pipe 6 penetrates the side wall of the outer die 8 and the inner sleeve 9 and is in communication with the material inlet flow channel 14.

[0044] The material injection port 2 of the distribution joint 1 is connected to the discharge end of the extruder, and the molten polyethylene raw material is extruded into the outer layer flow channel 28 and the extrusion flow channel 15 by the extruder.

[0045] The inner layer extrusion structure is in communication with the extrusion flow channel 15, and specifically, as shown in Figure 1 、 2 The inner layer extrusion structure comprises an inner die 18 and a distribution shuttle 20. The inner die 18 is trumpet-shaped, and the periphery of the material inlet of the inner die 18 is provided with a mounting plate 16. The inner die 18 is mounted on the end face of the extrusion end of the core mold 11 through the mounting plate 16, and the material inlet of the inner die 18 is in butt joint with the discharge port of the extrusion flow channel 15. A sealing gasket is arranged between the mounting plate 16 and the end face of the core mold 11 to improve the sealing performance therebetween.

[0046] The diverging cone 20 is conical in shape and is fixed in the inner die 18 by means of the mounting rod 17. The tip of the diverging cone 20 is directed towards the material inlet of the inner die 18, and an annular inner layer flow channel 19 is formed between the inner die 18 and the diverging cone 20, which extends outwards to the vicinity of the inner wall of the extruded polyethylene composite pipe outer layer 23. The annular inner layer flow channel 19 is in communication with the extrusion flow channel 15, so that the molten polyethylene raw material can flow from the extrusion flow channel 15 into the annular inner layer flow channel 19. Since the diverging cone 20 is conical in shape, the polyethylene raw material is evenly distributed into the annular inner layer flow channel 19.

[0047] In addition, as shown in Figure 2 the tip of the inner die 18 and the diverging cone 20 are both close to the inner wall of the extruded polyethylene composite pipe outer layer 23, so that when the polyethylene composite pipe outer layer 23 is extruded, a storage cavity 25 is formed between the polyethylene composite pipe outer layer 23, the inner die 18 and the diverging cone 20, which is in communication with the annular inner layer flow channel 19, and the polyethylene raw material in the annular inner layer flow channel 19 is extruded into the storage cavity 25.

[0048] At the same time, the tip of the diverging cone 20 is provided with a horizontal extension 24, which forms an extrusion gap 26 in communication with the storage cavity 25 between the horizontal extension 24 and the extruded polyethylene composite pipe outer layer 23, and the polyethylene raw material in the storage cavity 25 is extruded from the extrusion gap 26 to form the polyethylene composite pipe inner layer on the reinforcing layer.

[0049] As a preferred solution, a compression ring 21 for extruding the polyethylene composite pipe inner layer is connected to the diverging cone 20 by means of a support rod 22, and the compression ring 21 is located behind the diverging cone 20. The outer diameter of the compression ring 21 should match the outlet diameter of the annular inner layer flow channel 19, so that the compression ring 21 can extrude the polyethylene composite pipe inner layer.

[0050] The method for producing a polyethylene composite pipe using the above production device is as follows:

[0051] First, the stop valve 7 is closed, and the polyethylene raw material is placed in the extruder, and the polyethylene raw material is melted and extruded by the extruder. The molten polyethylene raw material is extruded into the polyethylene composite pipe outer layer 23 after passing through the material inlet 2, the first distribution channel 3, the first distribution pipe 5, the spiral flow channel 27 and the outer layer flow channel 28.

[0052] Then, when the polyethylene composite pipe outer layer 23 is extruded from the outer layer flow channel 28, the glue injection machine is started and injects glue into the glue spraying hose 30. The glue spraying hose 30 evenly sprays the glue onto the inner wall of the polyethylene composite pipe outer layer 23. Simultaneously, the fan blows a mixture of chopped basalt fibers and calcium carbonate powder into the distribution chamber 12. The mixture is evenly distributed from the distribution chamber 12 into the feed channel 10. After passing through the feed channel 10 and the guide plate 29, it is evenly blown onto the inner wall of the polyethylene composite pipe outer layer 23 and adhered to the inner wall of the polyethylene composite pipe outer layer 23 by the glue, forming a reinforcement layer.

[0053] Next, when the front end of the extruded polyethylene composite pipe outer layer 23 moves to the corresponding position at the end of the inner die 18, the stop valve 7 is opened, and the molten polyethylene raw material passes through the second distribution channel 4, the second distribution pipe 6, the feed flow channel 14, the extrusion flow channel 15 and the annular inner layer flow channel 19 at the same time, and is coated on the inner side of the reinforcement layer by the horizontal extension part 24 to form the inner layer of the polyethylene composite pipe.

[0054] During the process of the pipe being extruded and moving forward, the inner layer of the polyethylene composite pipe is compressed again by the pressure ring 21 to form an embryonic pipe.

[0055] Finally, the embryonic tube is shaped, cooled, and cut to obtain a polyethylene composite pipe.

[0056] Of course, as with conventional technology, continuous basalt fibers can also be wound around polyethylene composite pipes.

[0057] In this embodiment, the weight ratio of the chopped basalt fibers to the calcium carbonate powder is 1:1, the length of the chopped basalt fibers is 1 mm, and the particle size of the calcium carbonate powder is 50 nm.

[0058] By providing a feed channel 10 and guide plates 29, the present invention allows a mixture of chopped basalt fibers and calcium carbonate powder to be sprayed onto the outer layer 23 of an extruded polyethylene pipe, thereby forming a reinforcement layer that improves the radial stiffness of the polyethylene composite pipe. Furthermore, the present invention allows the outer layer, reinforcement layer, and inner layer of the polyethylene composite pipe to be formed in one step, improving production efficiency.

[0059] It should be noted that all features disclosed in this specification, or steps in all methods or processes disclosed, except for mutually exclusive features and / or steps, can be combined in any manner.

[0060] In addition, the above specific embodiments are exemplary, and those skilled in the art can think of various solutions under the inspiration of the disclosure of the present application, and these solutions also belong to the disclosed range of the present application and fall within the protection scope of the present application. Those skilled in the art should understand that the specification and drawings of the present application are illustrative and do not constitute a limitation on the claims. The protection scope of the present application is defined by the claims and their equivalents.

Claims

1. A production device for polyethylene composite pipes, characterized in that: The invention comprises a distribution joint assembly, an outer die (8), an inner sleeve (9) sleeved inside the outer die (8), a core die (11) arranged inside the inner sleeve (9), and an inner layer extrusion structure connected to the core die (11); an annular outer layer flow channel (28) for extruding an outer layer (23) of a polyethylene composite pipe is formed between the outer die (8) and the inner sleeve (9); an annular feeding channel (10) is formed between the inner sleeve (9) and the core die (11); an extrusion flow channel (15) is arranged in the core die (11); the distribution joint assembly is communicated with the outer layer flow channel (28) and the extrusion flow channel (15) respectively; and the inner layer extrusion structure is communicated with the extrusion flow channel (15); A guide plate (29) is provided on the end face of the extrusion end of the core die (11); the guide plate (29) is annularly surrounding the periphery of the extrusion flow channel (15); the end of the guide plate (29) away from the core die (11) is bent outward and extends to the outlet of the feeding channel (10), so that the cross section of the guide plate (29) is in the shape of an arc, so as to guide the material blown out from the feeding channel (10) to the inner wall of the outer layer (23) of the polyethylene composite pipe.

2. The production device of the polyethylene composite pipe according to claim 1, characterized in that: An annular glue spraying tube (30) is installed on the end of the extrusion end of the inner sleeve (9), and a plurality of glue spraying ports facing the outer layer (23) of the polyethylene composite pipe are evenly arranged on the glue spraying tube (30).

3. The production device of the polyethylene composite pipe according to claim 2, characterized in that: The invention also includes a distribution outer cover (13); the distribution outer cover (13) is installed on the end of the core mold (11) away from the extrusion end by means of bolts, and a distribution cavity (12) is formed between the distribution outer cover (13), the outer die (8), the inner sleeve (9) and the core mold (11), and the feeding channel (10) is connected to the distribution cavity (12).

4. The production device of the polyethylene composite pipe according to claim 3, characterized in that: The height of the outer layer flow channel (28) gradually increases from the feed end to the extrusion end, and the outer wall of the inner sleeve (9) is provided with a spiral flow channel (27), and the spiral flow channel (27) gradually becomes shallower from its feed end to the discharge end.

5. The production device of the polyethylene composite pipe according to claim 4, characterized in that: The distribution joint assembly comprises a distribution joint (1), a first distribution pipe (5) and a second distribution pipe (6) respectively connected to the distribution joint (1), and a stop valve (7) arranged on the second distribution pipe (6); an injection port (2) is arranged in the distribution joint (1), and a first distribution channel (3) and a second distribution channel (4) respectively connected to the injection port (2); the first distribution pipe (5) is connected to the first distribution channel (3), and the second distribution pipe (6) is connected to the second distribution channel (4); the first distribution pipe (5) passes through the side wall of the outer die (8) and is connected to the spiral flow channel (27), and the second distribution pipe (6) passes through the side wall of the outer die (8) and the inner sleeve (9) and is connected to the extrusion flow channel (15).

6. The production device of the polyethylene composite pipe according to claim 5, characterized in that: The inner layer extrusion structure comprises a trumpet-shaped inner die (18) and a conical diverter shuttle (20); the inner die (18) is mounted on the end face of the extrusion end of the core die (11) via a mounting plate (16); the diverter shuttle (20) is fixed in the inner die (18) via a mounting rod (17); an annular inner layer flow channel (19) extending toward the outer layer (23) of the polyethylene composite pipe is formed between the inner die (18) and the diverter shuttle (20); the annular inner layer flow channel (19) is communicated with the extrusion flow channel (15) The ends of the inner die (18) and the diverter shuttle (20) are both close to the outer layer (23) of the polyethylene composite pipe, so that a storage cavity (25) communicating with the annular inner layer flow channel (19) is formed between the outer layer (23) of the polyethylene composite pipe, the inner die (18) and the diverter shuttle (20); a horizontal extension portion (24) is provided at the end of the diverter shuttle (20), and an extrusion gap (26) communicating with the storage cavity (25) is formed between the horizontal extension portion (24) and the outer layer (23) of the polyethylene composite pipe.

7. The production device of the polyethylene composite pipe according to claim 6, characterized in that: The diverter shuttle (20) is connected to a pressure ring (21) for extruding the inner layer of the polyethylene composite pipe via a support rod (22).

8. A method for producing a polyethylene composite pipe, characterized in that: The production device of the polyethylene composite pipe according to any one of claims 1 to 7 comprises the following steps: Step 1: closing the stop valve (7), and extruding the molten polyethylene raw material through the first distribution channel (3), the first distribution pipe (5), the spiral flow channel (27) and the outer layer flow channel (28) to form the outer layer (23) of the polyethylene composite pipe; Step 2: When the outer layer (23) of the polyethylene composite pipe is extruded, glue is introduced into the glue spraying pipe (30) so that the glue is evenly sprayed on the inner wall of the outer layer (23) of the polyethylene composite pipe; at the same time, a mixture of chopped basalt fibers and calcium carbonate powder is blown into the distribution cavity (12). The mixture of chopped basalt fibers and calcium carbonate powder passes through the feeding channel (10) and the guide plate (29) and evenly adheres to the inner wall of the outer layer (23) of the polyethylene composite pipe to form a reinforcement layer; Step 3: When the front end of the outer layer (23) of the polyethylene composite pipe moves to the corresponding position at the end of the inner die (18), the stop valve (7) is opened, and the molten polyethylene raw material passes through the second distribution channel (4), the second distribution pipe (6), the extrusion flow channel (15) and the annular inner layer flow channel (19), and is coated on the inner side of the reinforcement layer by the horizontal extension portion (24), thereby forming the inner layer of the polyethylene composite pipe; Step 4: The inner layer of the polyethylene composite pipe is compressed by a compression ring (21) to form an embryonic tube; Step 5: After the embryonic tube is shaped, cooled and cut, a polyethylene composite pipe is obtained.

9. The method for producing a polyethylene composite pipe according to claim 8, characterized in that: The weight ratio of the chopped basalt fibers to the calcium carbonate powder is 1:1, the length of the chopped basalt fibers is 1 to 2 mm, and the particle size of the calcium carbonate powder is 50 to 100 nm.

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