Preparation equipment and preparation method of multi-layer composite medical tube

Abstract

The invention discloses preparation equipment and a preparation method of a multi-layer composite medical tube, and relates to the field of forming equipment of medical tubes, the preparation equipment comprises a workbench provided with a plurality of stations, and the stations at least comprise a gum dipping station and a curing station; the impregnation station is provided with a pipe body clamp and a gluing groove, the clamp is used for clamping a prefabricated TPU outer pipe preassembled with a spring layer and a metal braid layer, and pipe cavity gluing is completed through cooperation of a lifting mechanism and the gluing groove. The equipment is provided with a vacuum positive pressure switching device which is used for sucking TPU glue to the inner wall of a pipe in a negative pressure mode and blowing and scraping redundant glue in a positive pressure mode. And the curing station is provided with a curing device, so that rapid cross-linking curing is realized. The method can be used for efficiently preparing the composite medical tube with a stable structure and a uniform adhesive layer, and is suitable for precise medical instruments such as endoscope intubation tubes and the like.

Description

Technical Field

[0001] The present invention relates to the field of medical tube molding equipment, and in particular to a preparation device and a preparation method for a multi-layer composite medical tube. Background Art

[0002] With the continuous development of medical endoscopy technology, the insertion tube of the gastroenteroscope is not only required to have good flexibility and bending resistance, but also to meet high tensile and torque resistance. Existing gastroenteroscope insertion tubes generally adopt a three-layer composite structure, which includes an inner lining layer, an intermediate metal wire braided layer and an outer sheath layer. The inner lining layer is usually extruded from polytetrafluoroethylene (PTFE) or other low-friction plastics, with a smooth inner wall to ensure the smooth passage of operating instruments and gas and liquid channels; the intermediate metal wire braided layer: stainless steel or nickel-titanium alloy wire is woven / spirally wound on the outside of the inner lining tube to form a mesh or spiral structure that fits tightly to the inner lining, so as to improve the torque transmission accuracy and overall tensile strength of the pipeline; the outer sheath layer: coated with polyurethane (TPU) or other wear-resistant and chemical-resistant materials to provide a smooth outer surface and enhance wear resistance and disinfection resistance.

[0003] To meet more stringent mechanical performance requirements, a new composite tube structure was proposed. The tube body consists of an inner spring layer, an intermediate wire braid layer, and an outer sheath TPU layer, from the inside out. The inner spring layer uses a continuous stainless steel coil spring to enhance the tube's axial elastic recovery and compressive resistance. The intermediate wire braid layer is tightly wound around the outside of the adhesive layer, providing circumferential strength and torque transmission. The outer sheath TPU layer ensures a smooth and consistent surface and provides wear and chemical corrosion protection. The inner wall of the inner spring layer is impregnated with TPU glue, and the two metal layers are bonded to the outer sheath TPU layer through dipping or co-extrusion. However, existing three-layer pipe fabrication technology struggles to integrate this dual-layer metal structure in a single pass. Common processes currently face limitations: single-machine extrusion is limited: plastic extruders can only process thermoplastic polymers and are unable to coat the inner spring layer or the intermediate wire braid; wire braiding equipment cannot simultaneously form a composite layer from the inner spring layer to the intermediate wire braid; and existing single-shot extrusion technology is incapable of producing this composite pipe structure. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation device for a multi-layer composite medical tube, which has the advantages of uniform glue coating on the inner wall, high precision in controlling the thickness of the glue layer, and high production efficiency.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions: A preparation device for a multi-layer composite medical tube, comprising: A workbench, on which at least a dipping station and a curing station are provided; The upper part of the dipping station is provided with a tube clamp and the lower part is provided with a glue coating tank for clamping the prefabricated TPU outer tube pre-installed with an inner spring layer and an intermediate metal wire braided layer. The glue coating tank is filled with TPU glue. The tube clamp or the glue coating tank is provided with a lifting mechanism to allow the prefabricated TPU outer tube to enter and move out of the glue coating tank. The prefabricated TPU outer tube is arranged between the tube clamp and the glue coating tank to form a tube cavity. a vacuum-positive pressure switching device, connected to at least a portion of the tube body fixture and communicating with the tube cavity at the dipping station, for sucking air from the tube cavity in a negative pressure mode to draw TPU glue to the inner wall of the prefabricated TPU outer tube, and for introducing gas into the tube cavity in a positive pressure mode to scrape off excess glue; The curing station is provided with a curing device and a movable member for switching to the curing position, wherein the curing device is used to cross-link and cure the glue-coated pipe body.

[0006] Further configuration: the vacuum positive pressure switching device includes: A vacuum pump, used to extract the air in the lumen of the tube under negative pressure mode; A compressed gas source, used to introduce gas into the lumen under positive pressure mode; Solenoid valve, used to switch between the vacuum pump and the compressed air source to achieve switching between negative pressure suction mode and positive pressure purge mode; A pressure sensor is located on the tube body fixture and is arranged toward the tube cavity, and is used to detect the pressure in the tube cavity in real time; The first controller is electrically connected to the vacuum pump, compressed air source, solenoid valve and pressure sensor, and is used to control the start and stop of the vacuum pump and compressed air source and the switching of the solenoid valve according to the detected tube cavity pressure.

[0007] Further configuration: the curing device includes: UV light source; A rod-shaped base is connected to a movable member and is driven by the movable member to move up and down relative to the curing station in a vertical direction to adjust the relative position of the UV light source and the prefabricated TPU outer tube.

[0008] Further configuration: a micro-motion device is also included for micro-vibrating or rotating the prefabricated TPU outer tube during negative pressure and positive pressure stages to assist the self-leveling of the adhesive layer; the micro-motion device includes: An exciter is provided on the tube body fixture to provide micro-vibration motion to the prefabricated TPU outer tube on the tube body fixture; A rotating device is connected to the pipe body fixture and is used to drive the pipe body fixture to rotate at a constant speed; The second controller is connected to the vibrator and the rotating device by electrical signals, and is used to switch or superimpose the action modes of the vibrator and the rotating device according to a preset program, so as to apply micro-vibration or rotation to the tube body separately or simultaneously during the negative pressure suction and positive pressure purge stages.

[0009] Further configuration: further comprising: a loading station and an unloading station; the workbench is an annular workbench, and the loading station, the dipping station, the curing station and the unloading station are arranged in sequence on the circumference of the annular workbench; The driving mechanism is used to drive the annular workbench to rotate and sequentially transport the prefabricated TPU outer tube to the next workstation.

[0010] Further configuration: the tube body clamp includes an air path channel connected to the vacuum positive pressure switching device and an annular groove adapted to the prefabricated TPU outer tube, the prefabricated TPU outer tube is clamped in the annular groove, and the vacuum positive pressure switching device is connected to the air path channel through a rotary joint.

[0011] It is further configured that the viscosity of the TPU glue is within the range of 5–10 Pa·s.

[0012] Another object of the present invention is to provide a method for preparing the multi-layer composite medical tube using the manufacturing equipment, comprising the following steps: S1, loading positioning S11. Place the prefabricated TPU outer tube pre-installed with a stainless steel spring and an intermediate metal wire braid layer into the dipping station fixture on the workbench; S12. Adjust the axis of the prefabricated TPU outer tube to be coaxial with the center of the glue coating tank and keep them fixed; S2, negative pressure suction glue coating S21. Lower the tube body fixture or raise the glue coating tank so that the prefabricated TPU outer tube is immersed in the glue coating tank; S22, start the vacuum pump and reduce the pressure in the lumen to 20–50 mbar via the solenoid valve; S23: Maintain the negative pressure for 10–20 seconds to allow the TPU glue with a viscosity of 5–10 Pa·s to climb along the inner wall to the top of the tube; S3, positive pressure blowing and scraping film S31, raising the tube body fixture or lowering the glue coating tank to allow the prefabricated TPU outer tube to leave the glue coating tank; S32: Switch to the compressed air source and introduce 5–10 mbar positive pressure into the lumen through the solenoid valve. Maintain this pressure for 5–10 seconds to scrape off excess glue. S4, UV light curing S41, the workbench drives the pipe body to move to the curing station, and the moving component extends the curing device into the curing position inside the pipe body; S42, start the UV light source for 10–30 seconds, the wavelength of the UV light source is 365–405 nm, and the irradiation intensity is 10–50 mW / cm²; S43, after the curing is completed, the prefabricated TPU outer tube is moved out of the curing position; S5. Cutting.

[0013] Further setting: in step S2, step S24 is also included: synchronously starting the micro-motion device to apply ±1-2mm, 0.5-2Hz axial micro-vibration or 1-5rpm rotation to the prefabricated TPU outer tube.

[0014] In summary, the present invention has the following beneficial effects: First, the traditional "three-layer" extrusion and in-line braiding process cannot simultaneously coat the inner spring layer and the intermediate wire braid layer within the same tube. However, this device uses a vacuum in the dipping station to fully absorb the TPU glue along the inner wall of the tube. It then quickly switches to a positive-pressure "air knife" mode to scrape off the excess. The pressure differential and capillary force work together to form a single, uniform film. This allows for efficient and reliable lamination of the inner spring layer and intermediate wire braid layer to the inner wall of the prefabricated TPU outer tube, avoiding the weak bonds and interface weakening associated with multiple-section splicing or discrete bonding.

[0015] Secondly, the solution of the present invention precisely utilizes the timing, pressure, and rheological properties of the negative pressure suction and positive pressure scraping, which not only ensures full cavity infiltration, but also automatically and quantitatively leaves a controllable film thickness, breaking through the problem that conventional air knife or dip coating cannot be completed in narrow tube lumens. By forcing the TPU glue to penetrate into the micron-level gap between the inner spring layer and the middle metal wire braided layer during the negative pressure suction stage, and solidifying after the positive pressure "air knife" scraping, the remaining film not only relies on chemical adhesion, but also forms a mechanical interlock with the metal layer. Traditional processes rely solely on surface coating and extrusion, which makes it difficult to achieve such a deep TPU glue filling and bite action, thereby significantly improving the interlayer bonding strength and fatigue life.

[0016] Third, the present invention superimposes ±1–2mm axial micro-vibration or 1–5rpm slow rotation during both negative and positive pressure stages, leveraging shear and centrifugal forces to eliminate bubbles and smooth the adhesive film. This allows the semi-fluid adhesive to instantly level itself and eliminate tiny bubbles after millisecond pressure switching. This process achieves efficient defect removal within the confined lumen of an endoscope, a feat difficult to achieve with conventional air knife or vibration techniques on open surfaces.

[0017] Fourth, the annular workbench is linked with multiple workstations, forming a closed loop from loading → negative pressure gluing → positive pressure scraping → UV curing → unloading, which can realize assembly line production and reduce manual intervention; combined with the lifting mechanism, moving components, and curing device, the preparation cycle of a single tube can be shortened, greatly improving production capacity.

[0018] Fifth, in the present invention, TPU glue viscosity, surface tension, positive pressure difference, tube diameter and contact angle are clearly incorporated into a unified formula to guide parameter selection and thickness control, which is used for real-time parameter calibration and process stability assurance, breaking through the limitations of empirical parameter adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of a device for preparing a multi-layer composite medical tube; Figure 2 It is a structural diagram of the workbench; Figure 3 Schematic diagram of the structure of the tube body fixture; Figure 4 It is a structural diagram of the glue coating tank and curing device; Figure 5 This is the schematic diagram of the vacuum positive pressure switching device.

[0020] In the figure, 10, prefabricated TPU outer tube; 100. Workbench; 101. Loading station; 102. Dipping station; 103. Curing station; 104. Unloading station; 105. Driving mechanism; 106. Lifting mechanism; 200, pipe body fixture; 201, air passage; 202, annular groove; 203, rotary joint; 300, glue tank; 400, vacuum positive pressure switching device; 401, vacuum pump; 402, compressed air source; 403, solenoid valve; 404, pressure sensor; 405, first controller; 500, curing device; 501, moving member; 502, rod-shaped base; 503, UV light source; 600, micro-motion device; 601, exciter; 602, rotating device; 603, second controller. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below with reference to the accompanying drawings.

[0022] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0023] The present invention provides a preparation device for a multi-layer composite medical tube, such as Figure 1 and Figure 2As shown, the system comprises a workbench 100 and a drive mechanism 105. The workbench 100 is circular, horizontally arranged, and rotatable about its central axis. The workbench 100 is equipped with at least a dipping station 102 and a curing station 103. The drive mechanism 105 is located below the workbench 100 and mechanically connected to it, rotating the workbench 100 clockwise or counterclockwise at a constant speed, thereby sequentially transporting the prefabricated TPU outer tubes 10 to each functional station.

[0024] There is no limitation on the specific structural form of the driving mechanism 105. In this embodiment, the driving mechanism 105 can be one of the structural forms such as a stepping motor, a servo motor, a cylinder drive device, a chain transmission device or a cam divider, or a combination thereof. The driving mechanism 105 is connected to the rotary shaft of the workbench 100 and is arranged under the workbench 100. It can drive the workbench 100 intermittently or continuously, thereby realizing the orderly conversion of workstations and the gradual processing of the tube body.

[0025] In this embodiment, the workbench 100 is an annular workbench 100, and the dipping station 102 and the curing station 103 are arranged in sequence on the circumference of the annular workbench 100; this embodiment also includes a loading station 101 and an unloading station 104; specifically, the loading station 101, the dipping station 102, the curing station 103 and the unloading station 104 are arranged in sequence on the circumference of the annular workbench 100. The loading station 101 is connected to the feed end of the workbench 100 and is used to introduce the prefabricated TPU outer tube 10 to be processed; the dipping station 102 is arranged in a clockwise direction of the loading station 101 and is used to immerse the tube body in the glue; the curing station 103 is located in a clockwise direction of the dipping station 102 and is used to cure the prefabricated TPU outer tube 10 after dipping; the unloading station 104 is arranged in a clockwise direction of the curing station 103 and is used to receive the finished prefabricated TPU outer tube 10 after curing and transport it to the next process.

[0026] At the dipping station 102, a tube fixture 200 is located at its upper portion, and a glue coating tank 300 is located at its lower portion. The tube fixture 200 and glue coating tank 300 are arranged opposite each other, spaced vertically apart, and define a workspace between them for installing the prefabricated TPU outer tube 10 to be processed. Specifically, the prefabricated TPU outer tube 10 is positioned between the tube fixture 200 and the glue coating tank 300, forming a tube lumen. The tube fixture 200 is used to clamp the prefabricated TPU outer tube 10, which has been pre-installed with an inner spring layer and an intermediate wire braid layer, to ensure its stability and coaxiality during the dipping process. The glue coating tank 300 is used to hold TPU glue with a controlled viscosity within a certain range. It is positioned perpendicular to the axial direction of the prefabricated TPU outer tube 10, allowing the prefabricated TPU outer tube 10 to be vertically inserted into or removed from the glue coating tank 300 under the drive of the tube fixture 200.

[0027] In order to achieve the above-mentioned insertion and removal actions, at least one of the tube body fixture 200 or the glue coating tank 300 is provided with a lifting mechanism 106 to drive the tube body or the glue coating tank 300 to move in the vertical direction, thereby realizing the in and out switching of the prefabricated TPU outer tube 10 at different stages. During processing, the prefabricated TPU outer tube 10 is inserted into the glue coating tank 300 under the positioning of the tube body fixture 200, and a closed tubular cavity space is formed between the tube body fixture 200 and the glue coating tank 300 to provide an operating environment for subsequent suction. In this embodiment, reference Figure 4 The lifting mechanism 106 is preferably arranged on one side of the glue coating tank 300, and is suitable for driving the glue coating tank 300 to rise and fall.

[0028] There is no limitation on the specific structural form of the lifting mechanism 106. In this embodiment, the lifting mechanism 106 can be in the form of an electric push rod, a pneumatic cylinder, a slide rail slider assembly or a servo lifting device. The lifting mechanism 106 is connected to the bearing structure of the tube body clamp 200 or the glue coating tank 300 and is arranged on the upper or outer side of the workbench 100.

[0029] refer to Figure 3 While the specific structure of the tube fixture 200 is not limited, in this embodiment, the tube fixture 200 includes an air passage 201 connected to the vacuum-positive pressure switching device 400 and an annular groove 202 sized to match the prefabricated TPU outer tube 10. The prefabricated TPU outer tube 10 is tightly clamped in the annular groove 202 to ensure the tube's position remains stable during gluing and suction. The vacuum-positive pressure switching device 400 is rotatably connected to the air passage 201 via a rotary joint 203 provided on one side of the tube fixture 200.

[0030] refer to Figure 1 、 Figure 3 and Figure 4 The dipping station 102 is further provided with a vacuum-positive pressure switching device 400. The vacuum-positive pressure switching device 400 is connected to at least a portion of the structure provided on the tube body fixture 200. Specifically, the vacuum-positive pressure switching device 400 is connected to the tube cavity formed between the tube body fixture 200 and the glue coating tank 300 via a rotary joint 203. The vacuum-positive pressure switching device 400 is used to control the air pressure inside the tube cavity. Specifically, in the negative pressure working mode, the air in the tube cavity is sucked to form a low pressure state inside the tube cavity, thereby causing the TPU glue in the glue coating tank 300 to climb along the inner wall of the prefabricated TPU outer tube 10, thereby forming an attached glue layer. In the positive pressure working mode, gas is introduced into the tube cavity to increase the air pressure inside the tube cavity, thereby using the airflow to scrape off excess glue on the inner wall of the prefabricated TPU outer tube 10, thereby achieving the purpose of controlling the thickness and uniformity of the glue coating.

[0031] Specifically, one end of the tube lumen is sealed to the glue tank 300, while the other end is connected to a vacuum pump 401. The pumping rate is controlled at 1–2 L / min, with a target vacuum level of 20–50 mbar. This allows the TPU glue to rise to the top of the tube lumen within tens of milliseconds to seconds, forming a clear liquid-air interface with the unfilled portion. Once the TPU glue has filled the entire length of the tube, a relatively stable liquid-air interface is automatically established, indicating that the tube is "liquid-filled." The pressure is quickly switched (<100 ms) from negative to a slight positive pressure (5–10 mbar). This positive pressure pushes the TPU glue in the tube lumen back into the glue tank 300, effectively performing a subtle "air knife" scraping action on the tube's inner wall. The switch from negative to positive pressure occurs in milliseconds, preventing the TPU glue from accumulating in the center of the cavity and being scraped back almost instantly by the "air knife." The adhesion between the TPU glue and the TPU tube wall is greater than the TPU glue's own gravity and centrifugal force, allowing a thin film to remain stably on the wall. In this embodiment, the viscosity of the TPU glue is in the range of 5–10 Pa·s. Different viscosities can be selected based on the required wall thickness and molding conditions.

[0032] Furthermore, the amount of TPU glue remaining on the tube wall depends on the positive pressure, viscosity (η), tube wall surface energy, and the mechanical equilibrium of the glue-air-wall three-phase contact line. The vacuum-positive pressure switching device 400, the TPU glue used, and the inner surface of the prefabricated TPU outer tube 10 satisfy the following comprehensive relationship, ensuring that the residual glue layer thickness h on the inner wall of the tube cavity is within a controllable range: in: : Thickness of residual rubber layer on the inner wall of the tube; : tube inner radius; : TPU glue viscosity; : TPU glue-gas interfacial tension; : The pressure difference between the inside and outside of the lumen during positive pressure scraping; : air density; : Static contact angle of TPU glue on the tube wall.

[0033] In this embodiment, in order to more intuitively illustrate the meaning of the formula and its application, a specific calculation example is given below.

[0034] Take the inner radius of the tube ; Choose TPU glue viscosity cdotps; TPU glue-gas interfacial tension ; Pressure difference applied during positive pressure scraping stage (about 5 mbar); Air density ; contact angle .

[0035] First calculate the Caprilli number term: Then take its Power: Then calculate the contact angle correction term: Last substitution and a pre-factor of 0.94: It can be seen that under the above parameters, the residual adhesive layer thickness h on the inner wall of the tube is approximately 0.23 mm. This example shows that by properly selecting parameters such as pressure difference, TPU adhesive viscosity, interfacial tension, and contact angle, the formula can be used to accurately predict and control the adhesive coating thickness.

[0036] For further reference, Figure 2 and Figure 4 Curing station 103 is equipped with a curing device 500 and a movable member 501 for driving curing device 500 to a curing position. Curing device 500 is mounted on movable member 501 and can be moved vertically or in a desired direction by movable member 501 to position it at a curing position corresponding to the glue-coated tube. Curing device 500 is used to crosslink and cure the glue-coated tube, allowing the TPU glue adhered to the inner wall of the prefabricated TPU outer tube 10 to complete the crosslinking reaction quickly and form a stable adhesive film, ultimately completing the structure of the medical tube.

[0037] There is no specific limitation on the structural form of the movable member 501. A variety of drive modes and structural forms can be selected according to actual application requirements to achieve the up and down movement of the curing device 500 relative to the prefabricated TPU outer tube 10. In this embodiment, the movable member 501 can be a structure such as an electric push rod, a pneumatic cylinder, a slide block assembly, or a servo lift mechanism 106. The movable member 501 is installed above or to the side of the curing station 103 and is connected to the rod-shaped base 502 of the curing device 500. It can drive the curing device 500 to move up and down in a vertical direction or in a direction corresponding to the axial direction of the prefabricated TPU outer tube 10, so as to accurately adjust the relative position between the UV light source 503 and the prefabricated TPU outer tube 10, thereby achieving effective irradiation and curing of the rubber coating layer in the tube cavity.

[0038] On the basis of the above embodiment, as a further limited embodiment, Figure 5 As shown, the vacuum-positive pressure switching device 400 includes a vacuum pump 401, a compressed air source 402, a solenoid valve 403, a pressure sensor 404, and a first controller 405. The vacuum pump 401 is used to suction the interior of the tube lumen between the tube body fixture 200 in negative pressure mode, thereby expelling air from the lumen and allowing the TPU glue to adhere to the inner wall of the prefabricated TPU outer tube 10 under negative pressure. The compressed air source 402 is used to introduce air into the lumen in positive pressure mode to scrape off excess glue on the inner wall, thereby forming a uniform adhesive layer. The solenoid valve 403 is located between the vacuum pump 401 and the compressed air source 402 and is used to switch between the two, thereby switching between negative pressure suction mode and positive pressure purge mode. The pressure sensor 404 is located on the tube body fixture 200, facing the interior of the lumen, and is used to collect real-time pressure data within the lumen. The first controller 405 is electrically connected to the vacuum pump 401, the compressed gas source 402, the solenoid valve 403 and the pressure sensor 404 respectively, and is used to receive the feedback signal from the pressure sensor 404, and automatically control the start and stop status of the vacuum pump 401 and the compressed gas source 402 according to the detected pressure in the lumen, and at the same time control the on-off switching of the solenoid valve 403 to achieve precise regulation and automatic switching of the internal pressure of the lumen.

[0039] On the basis of the above embodiment, as a further limited embodiment, Figure 4 As shown, the curing device 500 includes a UV light source 503 and a rod-shaped base 502 connected to a movable member 501. The rod-shaped base 502 is a longitudinally extending structure, with one end fixedly connected to the movable member 501. The movable member 501 drives the base 502 to move vertically relative to the curing station 103, thereby adjusting the vertical position between the UV light source 503 and the prefabricated TPU outer tube 10 to be cured. Maintaining an appropriate irradiation distance between the curing light source and the surface of the adhesive layer facilitates uniform crosslinking and curing of the adhesive layer.

[0040] On the basis of the above embodiment, as a further limited embodiment, Figure 1 As shown, the equipment also includes a micro-motion device 600, which is arranged at the dipping station 102 and is used to apply micro-vibration or rotational motion to the prefabricated TPU outer tube 10 during the negative pressure suction stage and the positive pressure blowing stage to assist the self-leveling and uniform distribution of the glue in the tube cavity, thereby improving the coating quality.

[0041] The micro-motion device 600 includes an exciter 601 mounted on the tube fixture 200. The exciter 601 is used to drive the prefabricated TPU outer tube 10 clamped in the tube fixture 200 to generate axial or radial micro-vibrations. It also includes a rotating device 602, which is transmission-connected to the tube fixture 200 and is used to drive the tube fixture 200 to rotate at a constant speed about its axis. The micro-motion device 600 further includes a second controller 603, which is electrically connected to the exciter 601 and the rotating device 602, respectively. The second controller 603 is used to control the start and stop and motion states of the exciter 601 and the rotating device 602 according to a preset program. In negative and positive pressure modes, micro-vibration and rotation are applied separately or simultaneously, thereby optimizing the distribution uniformity and adhesion consistency of the TPU glue on the inner wall of the prefabricated TPU outer tube 10. Specifically, the system superimposes ±1–2mm axial micro-vibration or 1–5rpm slow rotation during negative and positive pressure stages, utilizing shear and centrifugal forces to eliminate bubbles and smooth the film. The combined effects of micro-vibration and rotation on fluid behavior are complex. This solution precisely balances amplitude, frequency, and rotational speed to achieve self-leveling and bubble removal within extremely confined spaces, a process difficult to foresee with conventional processes.

[0042] The present invention also provides a method for preparing the multi-layer composite medical tube using the above-mentioned preparation equipment, comprising the following steps: Step S1: Loading and positioning.

[0043] S11, placing the prefabricated TPU outer tube 10 pre-installed with a stainless steel spring layer and an intermediate metal wire braided layer in a tube body fixture 200 provided on the dipping station 102 of the workbench 100; S12, through the lifting mechanism 106 or the auxiliary positioning structure adjustment, the axis of the prefabricated TPU outer tube 10 is coaxially arranged with the central axis of the glue coating tank 300 located below, and remains stably fixed in this position to ensure coaxiality and uniformity in the subsequent glue coating process.

[0044] Step S2: negative pressure suction glue application.

[0045] S21, driving the lifting mechanism 106 to lower the tube body fixture 200 or raise the glue coating tank 300, so that the prefabricated TPU outer tube 10 is gradually immersed in the glue coating tank 300 until the set immersion depth is reached; S22, start the vacuum pump 401, and switch the solenoid valve 403 to pump the pressure inside the lumen to a negative pressure state of 20-50 mbar; S23, maintaining the negative pressure state for 10-20 seconds, so that the TPU glue with a viscosity of 5-10 Pa·s climbs upward along the inner wall of the tube body and evenly covers the inner surface of the tube cavity; Step S3: Positive pressure sweeping and scraping the membrane.

[0046] S31, controlling the tube body fixture 200 to rise or the glue coating tank 300 to descend by the lifting mechanism 106, so that the prefabricated TPU outer tube 10 is completely separated from the glue coating tank 300 to prevent excessive glue from continuing to adhere; S32, the solenoid valve 403 switches to the compressed air source 402 passage, and introduces 5-10 mbar positive pressure gas into the tube cavity for 5-10 seconds, so that the residual glue can be evenly scraped or blown into a thin layer, further controlling the thickness of the inner coating and improving the surface quality.

[0047] Step S4: UV light curing.

[0048] S41, the driving mechanism 105 drives the workbench 100 to rotate, transporting the glue-coated prefabricated TPU outer tube 10 to the curing station 103 located at the next position, and the moving member 501 drives the curing device 500 to extend vertically into the curing area inside the tube cavity; S42, start the UV light source 503 and irradiate according to the set parameters, with an irradiation time of 10-30 seconds, a wavelength of 365-405 nm, and an irradiation intensity of 10-50 mW / cm², to promote the full cross-linking and curing of the inner wall adhesive layer; S43, after curing is completed, the UV light source 503 is withdrawn to the standby position by the moving component 501, and the prefabricated TPU outer tube 10 is moved out of the curing station 103 to prepare for the next process.

[0049] Step S5: cutting.

[0050] The cured prefabricated TPU outer tube 10 is automatically or manually taken out from the unloading station 104 by the equipment, completing one molding cycle and waiting for subsequent testing or processing.

[0051] On the basis of the above embodiment, as a further limited embodiment, in step S2, step S24 is also included: during the above-mentioned negative pressure suction process, the micro-motion device 600 is started to apply axial micro-vibration of ±1-2mm and 0.5-2Hz to the prefabricated TPU outer tube 10, or slowly rotate at a speed of 1-5rpm to promote self-leveling, adhesion and diffusion of the glue on the inner wall of the tube cavity, thereby further improving the uniformity of the inner glue film.

[0052] The above embodiments are merely explanations of the present invention and are not limitations of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the embodiments as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A device for preparing a multi-layer composite medical tube, characterized in that: include: A workbench (100) is provided with at least a dipping station (102) and a curing station (103); The upper part of the dipping station (102) is provided with a tube body clamp (200), and the lower part is provided with a glue coating groove (300) for clamping a prefabricated TPU outer tube (10) pre-installed with an inner spring layer and an intermediate metal wire braided layer. The glue coating groove (300) is filled with TPU glue. The tube body clamp (200) or the glue coating groove (300) is provided with a lifting mechanism (106) to allow the prefabricated TPU outer tube (10) to enter and move out of the glue coating groove (300). The prefabricated TPU outer tube (10) is arranged between the tube body clamp (200) and the glue coating groove (300) to form a tube cavity. A vacuum-positive pressure switching device (400) is connected to at least a portion of the tube body fixture (200) and is in communication with the tube cavity at the dipping station (102), and is used to suck air from the tube cavity in a negative pressure mode to suck TPU glue to be adsorbed onto the inner wall of the prefabricated TPU outer tube (10), and to introduce gas into the tube cavity in a positive pressure mode to scrape off excess glue; The curing station (103) is provided with a curing device (500) and a moving member (501) for switching to a curing position, wherein the curing device (500) is used to cross-link and cure the pipe body after being coated with glue.

2. The equipment for preparing a multi-layer composite medical tube according to claim 1, characterized in that: The vacuum-positive pressure switching device (400) comprises: A vacuum pump (401) for sucking air from the lumen under negative pressure; a compressed gas source (402) for introducing gas into the lumen under positive pressure mode; A solenoid valve (403) is used to switch between the vacuum pump (401) and the compressed air source (402) to achieve switching between a negative pressure suction mode and a positive pressure purge mode; A pressure sensor (404), located on the tube body fixture (200) and disposed toward the tube cavity, for detecting the pressure in the tube cavity in real time; The first controller (405) is electrically connected to the vacuum pump (401), the compressed air source (402), the solenoid valve (403) and the pressure sensor (404), and is used to control the start and stop of the vacuum pump (401) and the compressed air source (402) and the switching of the solenoid valve (403) according to the detected lumen pressure.

3. The equipment for preparing a multi-layer composite medical tube according to claim 1, characterized in that: The curing device (500) comprises: UV light source (503); A rod-shaped base (502) is connected to a movable member (501) and is driven by the movable member (501) to move up and down in a vertical direction relative to a curing station (103) to adjust the relative position of a UV light source (503) and a prefabricated TPU outer tube (10).

4. The equipment for preparing a multi-layer composite medical tube according to claim 1, characterized in that: It also includes a micro-motion device (600) for micro-vibrating or rotating the tube body during negative pressure and positive pressure stages to assist the self-leveling of the adhesive layer; the micro-motion device (600) includes: An exciter (601) is provided on the tube body fixture (200) and provides micro-vibration motion to the tube body on the tube body fixture (200); A rotating device (602) is connected to the pipe clamp (200) in a transmission manner and is used to drive the pipe clamp (200) to rotate at a constant speed; The second controller (603) is electrically connected to the vibrator (601) and the rotating device (602) and is used to switch or superimpose the action modes of the vibrator (601) and the rotating device (602) according to a preset program, so as to apply micro-vibration or rotation to the tube body separately or simultaneously during the negative pressure suction and positive pressure purge stages.

5. The equipment for preparing a multi-layer composite medical tube according to claim 1, characterized in that: Also includes: A loading station (101) and an unloading station (104); the workbench (100) is an annular workbench (100), and the loading station (101), the dipping station (102), the curing station (103) and the unloading station (104) are arranged in sequence on the circumference of the annular workbench (100); The driving mechanism (105) is used to drive the annular workbench (100) to rotate and sequentially transport the prefabricated TPU outer tube (10) to the next work station.

6. The equipment for preparing a multi-layer composite medical tube according to claim 1, characterized in that: The tube body clamp (200) comprises an air passage (201) connected to a vacuum-positive-pressure switching device (400) and an annular groove (202) adapted to a prefabricated TPU outer tube (10); the prefabricated TPU outer tube (10) is clamped in the annular groove (202); and the vacuum-positive-pressure switching device (400) is connected to the air passage (201) via a rotary joint (203).

7. The equipment for preparing a multi-layer composite medical tube according to claim 1, characterized in that: The viscosity of the TPU glue is in the range of 5–10 Pa·s.

8. A method for preparing a multi-layer composite medical tube using the equipment for preparing the multi-layer composite medical tube according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, loading positioning S11, placing the prefabricated TPU outer tube (10) pre-installed with a stainless steel spring and an intermediate metal wire braided layer into a fixture at the dipping station (102) of the workbench (100); S12, adjusting so that the axis of the prefabricated TPU outer tube (10) is coaxial with the center of the glue coating tank (300) and keeps them fixed; S2, negative pressure suction glue coating S21, lowering the tube body fixture (200) or raising the glue coating tank (300) so that the prefabricated TPU outer tube (10) is immersed in the glue coating tank (300); S22, start the vacuum pump (401), and reduce the pressure in the lumen to 20-50 mbar via the solenoid valve (403); S23: Maintain the negative pressure for 10–20 seconds to allow the TPU glue with a viscosity of 5–10 Pa·s to climb along the inner wall to the top of the tube; S3, positive pressure blowing and scraping film S31, raising the tube body fixture (200) or lowering the glue coating tank (300) so that the prefabricated TPU outer tube (10) leaves the glue coating tank (300); S32, switch to the compressed air source (402), introduce 5-10 mbar positive pressure into the lumen through the solenoid valve (403), maintain for 5-10 seconds to scrape off excess glue; S4, UV light curing S41, the workbench (100) drives the tube body to move to the curing station (103), and the moving component (501) extends the curing device (500) into the curing position inside the prefabricated TPU outer tube (10); S42, start the UV light source (503) and irradiate for 10–30 seconds, the wavelength of the UV light source (503) is 365–405 nm, and the irradiation intensity is 10–50 mW / cm²; S43, after curing is completed, the prefabricated TPU outer tube (10) is moved out of the curing position; S5. Cutting.

9. The method for preparing the multi-layer composite medical tube according to claim 8, characterized in that: In step S2, step S24 is also included: synchronously starting the micro-motion device (600) to apply ±1-2 mm, 0.5-2 Hz axial micro-vibration or 1-5 rpm rotation to the prefabricated TPU outer tube (10).

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