Multi-cavity plastic conduit gas-assisted extrusion device

Abstract

The utility model relates to medical equipment manufacturing technical field especially is related to a kind of multi-cavity plastic catheter gas auxiliary extrusion device, it include: shunt cone is equipped with air inlet channel and multiple exhaust channels;Core rod connector is connected with shunt cone, it has first gas auxiliary cavity and air inlet channel intercommunication to form first air inlet auxiliary channel;Multiple core rods pass through core rod connector and connect exhaust channel to form exhaust auxiliary channel;Die and core rod connector are spaced apart to form compression setting cavity, and it is communicated with first air inlet auxiliary channel, exhaust auxiliary channel.The utility model is combined with die structure optimization, in extrusion process, using air inlet auxiliary adjustment and core rod exhaust gas auxiliary adjustment, the gas of multiple inner cavities excessively high pressure is discharged by suction pump, the gas pressure and flow of different inner cavities are separately controlled by setting the suction amount of different suction pump, not only avoid the problem that multi-cavity plastic catheter inner cavity is inflated and broken, but also can greatly improve the product quality of multi-cavity medical plastic catheter extrusion forming.

Description

Technical Field

[0001] This utility model relates to the field of medical device manufacturing technology, and in particular to a multi-lumen plastic catheter gas-assisted extrusion device. Background Technology

[0002] In modern medicine, minimally invasive interventional diagnosis and treatment are receiving increasing attention, often requiring the insertion of catheters into the patient's body for various surgical procedures. Therefore, medical catheters play a vital role in modern medical diagnosis and treatment. Generally, medical catheters are divided into single-lumen and multi-lumen types. Multi-lumen catheters have two or more cavities within their inner lumen, allowing for simultaneous infusion, drainage, drug administration, and the insertion of other auxiliary devices. This makes multi-lumen catheters more versatile than single-lumen catheters. Currently, the mainstream medical multi-lumen catheters on the market are mainly silicone catheters and plastic catheters. Medical plastic catheters, with their advantages of easy processing and lower price, are experiencing a year-on-year increase in demand.

[0003] Multi-lumen medical catheters are typically manufactured using continuous extrusion molding, involving components such as extruders, cooling and sizing devices, traction machines, and cutting machines. Besides the extrusion equipment, another crucial component is the die. The rationality of the die's internal flow channel structure and outlet structure significantly impacts the product quality of multi-lumen medical plastic catheters. This is primarily because the plastic melt itself possesses strong viscoelasticity. Under the stirring and transport conditions of the extruder screw, the plastic melt experiences significant shear and tensile stress within the die's flow channel. This causes the plastic melt and polymer chains to accumulate substantial elastic energy and orientation effects. When the melt is extruded from the die outlet, the release of the die wall constraint leads to elastic energy recovery, deorientation effects, and velocity rearrangement, resulting in issues such as die swell, extrusion deformation, and melt fracture—all detrimental to the quality of the medical catheter product. Meanwhile, because multi-lumen plastic catheters, such as two-lumen or three-lumen catheters, have multiple lumens of inconsistent shapes and sizes, the melt flow velocity distribution on the cross-section is extremely uneven, which in turn leads to uneven melt stress distribution. This makes problems such as die expansion, extrusion deformation, and melt fracture caused by extrusion of multi-lumen medical catheters more serious and prominent.

[0004] For multi-cavity extrusion dies, to effectively eliminate extrusion problems, an auxiliary gas layer needs to be applied to each cavity. This requires introducing multiple auxiliary gases into the various internal air channels of the die. However, the space available for machining multiple air channels within existing dies is very limited, making it difficult to design and machine the gas chambers and channels for gas-assisted extrusion. Therefore, it is necessary to optimize and improve the internal gas-assisted air channel structure of multi-cavity plastic conduit gas-assisted extrusion dies. Utility Model Content

[0005] This invention aims to at least improve one of the technical problems existing in the prior art. To this end, this invention proposes a multi-cavity plastic conduit gas-assisted extrusion device, which utilizes an external gas generator to produce air at a certain flow rate and pressure, and introduces multiple gas streams into the die, forming multiple auxiliary gas layers between the inner wall of the die flow channel, the outer walls of multiple mandrels, and the multi-cavity melt. Under the action of the auxiliary gas layers, the shear and tensile stresses between the melt and the inner wall of the die flow channel, as well as with the outer walls of the multiple mandrels, are eliminated, thereby solving the aforementioned extrusion problem.

[0006] The technical solution of this utility model is as follows:

[0007] A multi-lumen plastic conduit gas-assisted extrusion device, comprising:

[0008] The head body has a cavity, and the surface of the head body has a plurality of through holes communicating with the cavity;

[0009] A flow divider cone is embedded in the cavity of the head body. The flow divider cone has multiple flow channel holes and an inlet flow channel and multiple exhaust flow channels are opened inside the flow divider cone.

[0010] The mandrel connector is connected to the flow divider cone and has a first air auxiliary cavity, which communicates with the air intake channel to form a first air intake auxiliary channel;

[0011] Multiple mandrels, each mandrel passing through the mandrel connector and connected to the exhaust channel of the splitter cone to form an auxiliary exhaust channel;

[0012] The die is embedded in the cavity of the head body and is in close contact with the flow divider cone. The die and the mandrel connector are spaced apart to form a compression and shaping cavity. The compression and shaping cavity is connected to the first intake auxiliary flow channel and the exhaust auxiliary flow channel. The end of the die away from the flow divider cone is provided with an annular stepped portion, and the annular stepped portion near the compression and shaping cavity is provided with an inclined portion.

[0013] A retaining ring is fixedly connected to the head body to axially restrict the flow divider cone and the die.

[0014] An air-assisted cover plate is connected to the die and forms a second air intake auxiliary flow channel with the annular stepped portion. The second air intake auxiliary flow channel communicates with the compression and shaping cavity.

[0015] In one possible technical solution, the distance between the gas-assisted cover plate and the inclined portion is further in the range of 0.1mm to 0.4mm, which facilitates the formation of a uniform air cushion layer on the inner surface of the die, so that the melt flows in a plunger-like manner to form the plastic conduit melt.

[0016] In one possible technical solution, the inclined portion forms an angle of 5° to 20° with the axial direction of the die, which facilitates the formation of an air cushion layer that is tightly attached to the inner surface of the die within the compression and shaping cavity, and is beneficial for extruding a uniform plastic conduit melt.

[0017] In one possible technical solution, the die is further provided with a second air inlet, which is connected to an external air source device and can be fitted with an air inlet connector for pressurizing and filling the second air inlet channel.

[0018] In one possible technical solution, the crescent-shaped cylinder and the air-assisted cover plate have a notch at an angle to the connecting body, and the compression shaping cavity and the first air intake auxiliary flow channel are connected through the notch.

[0019] According to the multi-lumen plastic catheter gas-assisted extrusion device of this utility model, combined with die structure optimization, during the extrusion process, air intake auxiliary regulation and mandrel exhaust gas-assisted regulation are adopted to discharge the excessively high pressure gas in multiple inner lumens through the air pump. By setting the air pump volume of different air pumps, the gas pressure and flow rate of different inner lumens can be controlled individually. This not only avoids the problem of the inner lumen of the multi-lumen plastic catheter being burst, but also greatly improves the product quality of the multi-lumen medical plastic catheter extrusion molding.

[0020] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of a multi-cavity plastic conduit gas-assisted extrusion device according to an embodiment of the present invention;

[0023] Figure 2 This is a side view of the flow divider cone of the multi-lumen plastic conduit gas-assisted extrusion device according to an embodiment of the present invention;

[0024] Figure 3 This is a cross-sectional view (AA) of the flow divider cone of the gas-assisted extrusion device for a multi-cavity plastic conduit according to an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the mandrel connector of the multi-cavity plastic conduit gas-assisted extrusion device according to an embodiment of the present utility model;

[0026] Figure 5 This is another perspective schematic diagram of the mandrel connector of the multi-cavity plastic conduit gas-assisted extrusion device according to an embodiment of the present utility model;

[0027] Figure 6 This is a schematic diagram of the die structure of the gas-assisted extrusion device for a multi-cavity plastic conduit according to an embodiment of the present invention;

[0028] Figure 7 This is a schematic cross-sectional view of the die of the gas-assisted extrusion device for a multi-cavity plastic conduit according to an embodiment of the present invention;

[0029] Figure 8 yes Figure 1 Enlarged schematic diagram of part A in the diagram.

[0030] Figure label:

[0031] The head body 1 has a cavity 100, a through hole 101, and a gas connector 102;

[0032] Flow divider cone 2, flow channel hole 200, inlet flow channel 201, first exhaust flow channel 2021, second exhaust flow channel 2022;

[0033] Core rod connector 3, first air auxiliary cavity 300, first air inlet auxiliary flow channel 3001, connecting body 310, crescent cylinder 320, core rod cylinder 330;

[0034] First core rod 41, second core rod 42;

[0035] Die 5, annular stepped part 500, inclined part 5001, second air auxiliary port 501;

[0036] Card Circle 6;

[0037] 7. Air-assisted cover plate. Detailed Implementation

[0038] The embodiments of this utility model are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. It should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application.

[0039] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0041] The terms "first," "second," "third," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects and not to describe a particular order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, it may include a series of steps or units, or optionally, steps or units not listed, or other steps or units inherent to these processes, methods, products, or devices.

[0042] The accompanying drawings show only the portions relevant to this application, not all of them. Before discussing exemplary embodiments in more detail, it should be noted that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe operations (or steps) as sequential processes, many of these operations may be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations may be rearranged. The process may be terminated when its operation is completed, but may also have additional steps not included in the drawings. The process may correspond to a method, function, procedure, subroutine, subprogram, etc.

[0043] The terms “component,” “module,” “system,” “unit,” etc., used in this specification are used to refer to computer-related entities, hardware, firmware, combinations of hardware and software, software, or software in execution. For example, a unit can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, a thread of execution, a program, and / or distributed between two or more computers. Furthermore, these units can be executed from various computer-readable media on which various data structures are stored. Units can communicate, for example, via local and / or remote processes based on signals having one or more data packets (e.g., data from a second unit interacting with another unit between a local system, a distributed system, and / or a network; for example, the Internet interacting with other systems via signals).

[0044] Example 1

[0045] like Figures 1 to 8 As shown, this embodiment provides a multi-lumen plastic conduit gas-assisted extrusion device, comprising:

[0046] The head body 1 has a cavity 100. The surface of the head body 1 has a plurality of through holes 101 that communicate with the cavity 100. The through holes 101 are used for ventilation or exhaust. The through holes 101 can be fitted with gas connectors 102 for connecting to external gas source equipment or precision air pumps.

[0047] The flow divider cone 2 is embedded in the cavity 100 of the head body 1. The flow divider cone 2 has multiple flow channel holes 200. The flow divider cone 2 has an inlet flow channel 201 and multiple exhaust flow channels. Specifically, in this embodiment, the exhaust flow channels include a first exhaust flow channel 2021 and a second exhaust flow channel 2022, which are respectively aligned with the through hole of the head body 1 to facilitate extension to the outside of the head body 1 for connection to an external air pump device. The inlet flow channel 201 is aligned with the through hole of the head body 1 to facilitate extension to the outside of the head body 1 for connection to an external air source device.

[0048] The mandrel connector 3 is connected to the flow divider cone 2 and has a first gas auxiliary cavity 300. The first gas auxiliary cavity 300 is connected to the inlet flow channel to form a first inlet auxiliary flow channel 3001, which is used to introduce internal auxiliary gas into the surface of multiple mandrels in the die to form multiple internal gas auxiliary gas layers.

[0049] Multiple mandrels, each mandrel passing through the mandrel connector 3 and connected to the exhaust channel of the flow divider cone 2 to form an auxiliary exhaust channel;

[0050] The die 5 is embedded in the cavity 100 of the head body 1 and is in close contact with the flow divider cone 2. The die 5 and the mandrel connector 3 are spaced apart to form a compression and shaping cavity. The compression and shaping cavity is connected to the first intake auxiliary flow channel 3001 and the exhaust auxiliary flow channel. The end of the die 5 away from the flow divider cone 2 is provided with an annular stepped portion 500, and the annular stepped portion 500 near the compression and shaping cavity is provided with an inclined portion 5001.

[0051] The retaining ring 6 is fixedly connected to the head body 1 to axially restrict the flow divider cone 2 and the die 5;

[0052] The air-assisted cover plate 7 is connected to the die 5 and forms a second air intake auxiliary flow channel with the annular stepped portion 500. The second air intake auxiliary flow channel communicates with the compression and shaping cavity.

[0053] It should be noted that, in this embodiment, the mandrel connector 3 includes:

[0054] The connecting body 310 is in the shape of a hollow frustum, and its outer diameter gradually shrinks along the extrusion direction. The connecting body 310 is connected to the flow divider cone 2 by internal and external threads.

[0055] The crescent-shaped tube 320 is connected to and communicates with the connecting body 310, wherein the diameter of the circle containing the outer wall of the crescent-shaped tube 320 is equal to the minimum diameter of the connecting body 310;

[0056] The mandrel cylinder 330 is connected to and communicates with the connecting body 310, wherein the mandrel cylinder 330 is tangent to the minimum diameter circle of the connecting body 310, and the mandrel cylinder 330 is located outside the crescent cylinder 320. The crescent cylinder 320 and the mandrel cylinder 330 can be used for multi-mandrel insertion and connection with the diverter cone 2 for extruding multi-lumen medical plastic catheters.

[0057] It should be noted that the mandrel connector 3 includes two sleeves with different inner diameters. The mandrel passes through each sleeve and is threadedly fixed to the diverter cone 2. A gap exists between each mandrel and the inner wall of the sleeve, allowing for the introduction of multiple internal auxiliary gases to the multiple inner wall surfaces of the multi-lumen medical plastic catheter to assist in the extrusion of the multi-lumen medical plastic catheter. In this embodiment, the mandrel includes:

[0058] The first core rod 41 passes through the crescent cylinder 320 and is threadedly connected to the flow divider cone 2;

[0059] The second mandrel 42 passes through the mandrel cylinder 330 and is threadedly connected to the flow divider cone 2. A gap of about 0.2 mm is reserved between the first mandrel 41 and the inner wall surface of the crescent cylinder 320, and a gap of about 0.2 mm is reserved between the second mandrel 42 and the inner wall surface of the mandrel cylinder 330. This gap is used to regulate the gas pressure of each cavity while extruding the multi-cavity medical plastic catheter. By discharging the excess gas in the gas-assisted layer of each cavity through a vacuum pump, the excessive gas pressure in the cavity is prevented from bursting the multi-cavity medical plastic catheter.

[0060] It should be noted that in this embodiment, the compression shaping cavity is connected to the first air intake auxiliary channel 3001. Specifically, there is a notch at an angle to the connecting body 310 between the end of the crescent-shaped cylinder 320 away from the connecting body 310 and the end of the air auxiliary cover plate 7. The compression shaping cavity and the first air intake auxiliary channel 3001 are connected through the notch.

[0061] It should be noted that, in this embodiment, the side wall of the die 5 is provided with a second auxiliary air port 501 that connects to an external air source device, and an air inlet connector can be installed for pressurizing and filling the second auxiliary air inlet channel.

[0062] It should be noted that, in this embodiment, the distance between the gas-assisted cover plate and the inclined portion is in the range of 0.1mm to 0.4mm, which facilitates the formation of a uniform air cushion layer on the inner surface of the die 5, so that the melt flows in a plunger-like manner to form the plastic conduit melt.

[0063] It should be noted that, in this embodiment, the inclined portion forms an angle of 5° to 20° with the axial direction of the die, which facilitates the formation of an air cushion layer that is tightly attached to the inner surface of the die 5 in the compression and shaping cavity, and is beneficial for extruding a uniform plastic conduit melt.

[0064] According to the multi-lumen plastic catheter gas-assisted extrusion device of this utility model, through the mandrel connector and further optimization of the die structure, during the extrusion process, air intake auxiliary regulation and mandrel exhaust gas-assisted regulation are adopted to discharge the excessively high pressure gas in multiple inner lumens through the air pump. By setting the air volume of different air pumps, the gas pressure and flow rate of different inner lumens can be controlled individually. This not only avoids the problem of the inner lumen of the multi-lumen plastic catheter being burst, but also greatly improves the product quality of the multi-lumen medical plastic catheter extrusion molding.

[0065] Example 2

[0066] like Figures 1 to 8 As shown, this embodiment provides a gas-assisted extrusion method for multi-lumen plastic conduits based on Embodiment 1. The method includes the following steps:

[0067] S1, Extrusion preparation: Connect the device to the air source equipment, each exhaust channel is independently controlled, and after fixing the heating ring around the outer wall of the die, connect it to the extruder.

[0068] S2, Extrusion Operation: The plastic raw material is introduced into the extruder, the power is turned on, and the extruder and die are heated until the preset temperature is reached. Then the extrusion operation is carried out to obtain a plastic conduit melt containing multiple cavities. The extrusion process includes inlet gas-assisted regulation and mandrel exhaust gas-assisted regulation. The thickness of the gas-assisted layer is adjusted based on the inlet gas-assisted regulation, and the gas pressure of the corresponding cavity of each mandrel is adjusted to achieve balance based on the exhaust gas-assisted regulation of each mandrel.

[0069] S5, Water-cooled molding: The plastic conduit melt is drawn into a cooling water tank to obtain a multi-lumen medical plastic conduit.

[0070] It should be noted that, in this embodiment, S2, the intake auxiliary adjustment includes:

[0071] The thickness of the first gas-assisted layer is adjusted by adjusting the distance between each mandrel and the mandrel connector.

[0072] The thickness of the second gas-assisted layer is adjusted by adjusting the distance between the gas-assisted cover plate and the inclined portion.

[0073] It should be noted that, in this embodiment, in S2, the mandrel exhaust gas-assisted adjustment specifically involves adjusting the exhaust volume of each mandrel's exhaust channel to balance the gas pressure in the inner and outer layers of the plastic conduit melt corresponding to that mandrel. This mainly includes:

[0074] Obtain the gas pressure inside the cavity of each mandrel;

[0075] Based on the comparison of gas pressure in each inner cavity, if the gas pressure is the same, the exhaust volume of each mandrel in the exhaust channel is controlled to be equal. If the gas pressure is different, the exhaust volume of the mandrel in the exhaust channel is adjusted to keep the gas pressure in each inner cavity the same, so as to obtain the adjusted gas pressure.

[0076] Adjust the intake pressure of the second intake auxiliary channel according to the adjusted gas pressure to make the pressure of the inner and outer gas auxiliary layers of the melt equal, so as to stably output the plastic conduit melt with multiple inner cavities.

[0077] According to the gas-assisted extrusion method for multi-lumen plastic catheters of this utility model, combined with die structure optimization, during the extrusion process, air intake auxiliary regulation and mandrel exhaust gas-assisted regulation are adopted to discharge excessively high-pressure gas in multiple inner lumens through a vacuum pump. By setting the suction volume of different vacuum pumps, the gas pressure and flow rate of different inner lumens can be controlled individually. This not only avoids the problem of the inner lumen of the multi-lumen plastic catheter being burst, but also greatly improves the product quality of multi-lumen medical plastic catheters extruded and molded.

[0078] The gas-assisted extrusion method for multi-lumen plastic catheters according to this invention can greatly eliminate problems such as mold expansion, extrusion deformation and melt fracture of multi-lumen medical plastic catheters.

[0079] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the utility model.

[0080] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0081] Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The reference to "embodiment" herein means that a specific feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily indicate the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0082] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A multi-lumen plastic catheter gas-assisted extrusion apparatus, characterized by, include: The head body (1) has a cavity (100), and the surface of the head body (1) is provided with a plurality of through holes communicating with the cavity (100); The flow divider cone (2) is embedded in the cavity (100) of the head body (1). The flow divider cone (2) has multiple flow channel holes (200). The flow divider cone (2) has an inlet flow channel (201) and multiple exhaust flow channels. The mandrel connector (3) is connected to the flow divider cone (2) and has a first air auxiliary cavity (300), which is connected to the air intake channel to form a first air intake auxiliary channel (3001). Multiple mandrels, each mandrel passing through the mandrel connector (3) and connected to the exhaust channel of the split cone (2) to form an auxiliary exhaust channel; The die (5) is embedded in the cavity (100) of the head body (1) and is in close contact with the flow divider cone (2). The die (5) and the mandrel connector (3) are spaced apart to form a compression and shaping cavity. The compression and shaping cavity is connected to the first intake auxiliary flow channel (3001) and the exhaust auxiliary flow channel. The end of the die (5) away from the flow divider cone (2) is provided with an annular stepped portion (500), and the annular stepped portion (500) near the compression and shaping cavity is provided with an inclined portion (5001). The retaining ring (6) is fixedly connected to the head body (1) to axially restrict the flow divider cone (2) and the die (5). The air-assisted cover plate (7) is connected to the die (5) and forms a second air intake auxiliary channel with the annular stepped portion (500). The second air intake auxiliary channel is connected to the compression and shaping cavity.

2. The multi-lumen plastic catheter gas-assisted extrusion apparatus of claim 1, wherein, The mandrel connector (3) includes: The connecting body (310) is connected to the diversion cone (2); The crescent-shaped tube (320) is connected to and communicates with the connecting body (310); The mandrel cylinder (330) is connected to and communicates with the connecting body (310).

3. Multi-lumen plastic catheter gas-assist extrusion apparatus according to claim 1 or 2, characterized in that The core rod includes: The first core rod (41) passes through the crescent tube (320) and is connected to the flow divider cone (2), wherein there is a gap between the first core rod (41) and the crescent tube (320); The second core rod (42) passes through the core rod cylinder (330) and is connected to the flow divider cone (2), wherein there is a gap between the second core rod (42) and the core rod cylinder (330).

4. The multi-lumen plastic catheter gas-assisted extrusion apparatus of claim 2, wherein, The connecting body (310) is in the shape of a hollow frustum, and its outer diameter gradually shrinks along the extrusion direction.

5. The multi-lumen plastic catheter gas-assisted extrusion apparatus of claim 1, wherein, The distance between the air-assisted cover plate (7) and the inclined part (5001) is 0.1mm to 0.4mm.

6. The multi-lumen plastic catheter gas-assisted extrusion apparatus of claim 1, wherein, The angle between the inclined portion (5001) and the axial direction of the die (5) is 5° to 20°.

7. The multi-lumen plastic catheter gas-assisted extrusion apparatus of claim 1, wherein, The die (5) is provided with a second auxiliary air port (501) for connection to an external air source device.

8. The multi-lumen plastic conduit gas-assisted extrusion device according to claim 2, characterized in that, The crescent-shaped tube (320) and the air-assisted cover plate (7) have a notch at an angle to the connecting body (310).

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