A medical catheter forming mold, a melt head device, a forming process method, and a catheter

Abstract

The present application belongs to the technical field of polymer material forming, and relates to a medical catheter, in particular to a medical catheter forming die, a melt head device and a catheter forming process. The variable cross-section double-lumen tube die comprises a flat-elliptical covered double-lumen catheter forming runner one and a tearable double-lumen tube forming runner two. The on-off of the covered extrusion channel is controlled by a swing cylinder, so that the single-lumen tube body and the double-lumen tube body are integrally formed. The average breaking force at the stepped cross-section is between 160-180 N, avoiding the risk of catheter breakage during use. The die structure is simple and easy to operate. The melt head device can realize one-step forming of the stepped and head-end melt head of the catheter, avoiding unstable quality caused by two operations, and making the product consistent. The medical catheter forming process is simple and easy to operate, does not require professional technical personnel, has low cost and low energy consumption, is non-toxic and odorless, and can significantly improve production efficiency.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of polymer material forming, and relates to a medical catheter, in particular to a medical catheter forming die and a melting head device, and a process method for forming a medical catheter by using the forming die and the melting head device. BACKGROUND

[0002] Hemodialysis is to drain the blood in the body to a dialyzer to remove metabolic waste in the body and maintain electrolyte and acid-base balance. The hemodialysis catheter is an intravascular catheter used for dialysis treatment, which is a channel connecting the human blood vessel and the dialyzer. When hemodialysis treatment is performed, the blood of the patient is first introduced out from the blood inlet of the hemodialysis catheter, and then the dialyzer performs dialysis on the blood. The blood treated by the dialyzer is fed back into the human body from the blood return port of the hemodialysis catheter.

[0003] At present, in the clinical use process of the ordinary catheter, the dialysis blood flow becomes smaller with the increase of the indwelling time, which cannot meet the dialysis requirements, and seriously affects the quality level of the patient. Therefore, the high-flow hemodialysis catheter is the future development direction. The ladder type catheter is a new type of structure gradually accepted by the market, which can effectively prevent the occurrence of problems such as adhesion and thrombus during dialysis, and ensure the stability of blood flow and meet the clinical needs.

[0004] At present, most of the ladder catheters on the market are formed by the process of first extruding a double-lumen catheter, then extruding a single-lumen catheter, and then melting the double-lumen catheter and the single-lumen catheter together. This method is complex, and the butt joint of the double-lumen catheter and the single-lumen catheter has low fracture force, which has a high risk when used in the human body. Therefore, it is a problem to be considered to develop a new forming process and an extrusion die, so that the double-lumen catheter and the single-lumen catheter can be partially integrally formed by changing the catheter cross section during extrusion forming, to improve the fracture force and reduce the clinical risk.

[0005] In addition, the ladder forming and the melting forming of the soft head of most catheters on the market use two dies and are formed in two times, which is complex in operation and wastes manpower. Therefore, it is a problem to be solved to develop a device capable of forming the ladder type tip of the catheter, so that the ladder type and the soft head of the catheter can be formed at one time, to avoid the quality instability caused by two operations, save manpower, reduce the process, have low cost, have low technical requirements for workers, form the ladder type tip at one time, and have good product consistency. SUMMARY

[0006] Based on this, the purpose of the present application is to provide a medical catheter, a forming die and a melting head device, and further provide a process method for forming a medical catheter by using the forming die and the melting head device.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] The application provides a variable cross-section double-lumen tube mold for medical catheter forming, which is characterized by mainly comprising a swing cylinder 33, a flow channel shunt 30, a head body 38, a core rod 48, a die 49, a cladding shunt shuttle 46 and a die heating body 50; the flow channel shunt 30 is internally provided with a tearable double-lumen tube flow channel one 39 and a cladding flow channel one 40; the head body 38 is internally provided with a conical inner cavity penetrating through the head body and tearable double-lumen tube flow channel two 41 and cladding flow channel two 42 vertically distributed with the conical inner cavity; the core rod 48 and the die 49 form a cladding flow channel four 53, and the cladding shunt shuttle 46 and the die heating body 50 form a cladding flow channel three 54.

[0009] The cladding flow channel four 53, the cladding flow channel three 54 and the cladding flow channel two 42 are communicated to form an oblate cladding double-lumen catheter forming flow channel one for forming the oblate cladding double-lumen catheter; the core rod 48 and the cladding shunt shuttle 46 form a tearable double-lumen tube flow channel three 52, which is communicated with the tearable double-lumen tube flow channel two 41 to form a tearable double-lumen tube forming flow channel two for forming the tearable double-lumen tube.

[0010] Further, the swing cylinder 33 is fixed on a cylinder connecting plate 34 through bolt connection, the cylinder connecting plate 34 is threadedly connected with a cylinder fixing plate 36 through a heat insulation plate two 35, and the cylinder fixing plate 36 is threadedly connected with the head body 38 through a heat insulation plate one 37; the swing cylinder 33 drives and controls an on-off core shaft 59 through a shaft coupling 32, the on-off core shaft 59 is connected with the flow channel shunt 30 through a limiting bolt 31, and the limiting bolt 31 limits the position of the core shaft.

[0011] Further, the flow channel shunt 30 is provided with an internal thread hole 55 on the side close to the extruder and is threadedly connected with the extruder through a connecting piece; meanwhile, the flow channel shunt 30 is threadedly connected with the head body 38 through four counterbores 56; a hole 60 for placing the on-off core shaft 59 is formed on the upper side, an internal through hole 61 perpendicular to the axial direction is formed on the on-off core shaft 59, and the on-off of the cladding flow channel one 40 is controlled by rotating the direction of the internal through hole 61.

[0012] Further, the head body 38 is provided with four thread holes parallel to the axial line on the side close to the die and is boltedly connected with the die heating body 50, and is provided with an internal thread hole on the other side and is threadedly connected with one end of the rear gland 44 with an external thread hole; the other end of the rear gland 44 is provided with an internal thread hole and is connected with the fixing nut 43; one side of the die heating body 50 is provided with an internal thread and is threadedly connected with the front pressing plate 51 and tightly presses the die 49; the die 49 is installed in the inner cavity of the die heating body 50.

[0013] Further, the mold further comprises a tearable double-cavity tube shunt 45 which is in interference fit with the outer surface of the shunt 46 and the inner surface of the shank 48; the tearable double-cavity tube shunt 45 is provided with a positioning hole on one side for placing a positioning bolt 47; the positioning bolt 47 and the positioning hole on one side of the shank 48 are in mutual fit to realize positioning of the shank; the shank 48 is provided with two circular through holes 57 which are welded with two core pins 58 respectively for separately adjusting the size of the air intake to ensure the size consistency of the two inner holes after the product is formed.

[0014] The application also provides a stepped melting head device for forming medical catheters, which comprises a heating coil assembly, a guide rail 1 for adjusting the overall position of the heating coil assembly, a high-frequency power supply shell 2 connected with the guide rail 1 through bolts and internally provided with a high-frequency power supply module, a guide rail fixing clamp 3 for locking the heating coil assembly and connected with the sliding block through threads, a heating coil fixing plate 5 connected with the heating coil assembly through a joint at one end and welded with the high-frequency power supply shell 2 at the other end, a blowing module 6, a mold lower fixing block 7, a mold locking knob 8, a locking knob fixing block 9, a mold upper fixing block 12, a melting head device fixing plate 10 connected with the guide rail 1 through bolts, and a cooling port 11.

[0015] The heating coil assembly comprises a heating coil one 4 and a heating coil two 13, the main tube single-cavity tube part 23 and the soft head tube 24 are fused by controlling the parameters of the heating coil one 4, and the main tube stepped slope 25 is fused by controlling the parameters of the heating coil two 13; the materials of the heating coil one 4 and the heating coil two 13 both comprise copper wires, the wire diameter of the copper wires is 0.1-2mm, and the pitch is 0.1-6mm.

[0016] Further, a thread is arranged in the middle of the locking knob fixing block 9, and a threaded hole is arranged in the middle of the mold upper fixing block 12; the mold locking knob 8 is connected with the mold upper fixing block 12 through the locking knob fixing block 9, and is used for fixing the melting head mold 14.

[0017] Further, four threaded holes are arranged below the mold lower fixing block 7, and the mold lower fixing block 7 is connected with the melting head device fixing plate 10 through bolts; two threaded holes are arranged above the mold lower fixing block 7, and the mold lower fixing block 7 is connected with the locking knob fixing block 9 through bolts; four threaded holes are arranged above the left of the mold lower fixing block 7, and the mold lower fixing block 7 is connected with the blowing module 6 through bolts; a plurality of mold cooling holes 11 for cooling are arranged on the blowing module 6; a rectangular recess one 28 is arranged in the mold lower fixing block 7, a rectangular recess two 29 is arranged below the mold upper fixing block 12, and the positions of the recess one 28 and the recess two 29 correspond to each other and are used for placing the melting head mold 14.

[0018] Further, one end of the melt head mold 14 is provided with a fixing ring 15, the fixing ring 15 is provided with a fixing plane 17, the fixing plane 17 is installed in the groove of the mold lower fixing block 7 and the mold upper fixing block 12; the melt head mold 14 is provided with an inner cavity 18 with the same shape as the pipe body; the inner cavity 18 includes an inner cavity one 18-1 for placing the main body pipe ladder type and an inner cavity two 18-2 for placing the soft head pipe; the inner cavity two 18-2 has a certain taper, wherein the single side taper is 1°-5°.

[0019] The application further provides a process method for forming a medical catheter by using the variable cross-section double-cavity pipe mold and the ladder type melt head device, which is characterized by mainly including the following steps.

[0020] S1, extrusion and cutting of the main body pipe: taking a high polymer material as a main raw material, a main body pipe is prepared by selecting a suitable extruder and performing specific parameter control, extrusion and cutting; the main body pipe is ladder type, including a double-cavity pipe part 22 with a length of 180-203 mm, a single-cavity pipe part 23 with a length of 10-50 mm and a ladder inclined plane 25;

[0021] S2, extrusion and cutting of the soft head pipe: taking a high polymer material as a main raw material, a soft head pipe 24 is prepared by selecting a suitable extruder and performing specific parameter control, extrusion and cutting; the length of the soft head pipe 24 is 1-3 mm;

[0022] S3, forming of the medical catheter: the main body pipe ladder inclined plane 25 position and the single-cavity pipe part 23 and the soft head pipe 24 are integrated by the ladder type melt head device to obtain the medical catheter;

[0023] In the step S1, the extrusion of the double-cavity pipe part 22 and the single-cavity pipe part 23 is realized by selecting any one of the variable cross-section double-cavity pipe molds in claims 1-5; the double-cavity pipe part 22 is a flat elliptical covered double-cavity catheter, and the single-cavity pipe part 23 is prepared by cutting the tearable double-cavity pipe; the flat elliptical covered double-cavity catheter is obtained by flow channel one extrusion, and the tearable double-cavity pipe is obtained by flow channel two extrusion;

[0024] The catheter forming in the step S3 is realized by selecting any one of the ladder type melt head devices in claims 6-10, and the melt welding parameters of the single-cavity pipe part 23 and the soft head pipe 24 are as follows: heating power 70-100%, preheating 1-3 s, heating 3-6 s, advancing 7-12 s, holding 1-8 s, and cooling 10-16 s; the forming parameters of the ladder inclined plane 25 position are as follows: heating power 70-100%, preheating 1-4 s, heating 4-8 s, advancing 7-12 s, holding 3-10 s, and cooling 10-18 s.

[0025] Further, the extrusion and cutting of the main tube in step S1 mainly includes the following steps:

[0026] S11, extrusion of the main tube precursor: any one of the high molecular materials of polyurethane elastomer, polyvinyl chloride, polypropylene, nylon elastomer with a Shore hardness of 60A-95A or 40D-60D is selected, the polyurethane elastomer, polypropylene, and nylon elastomer are dried by a dehumidifying dryer for 4-6 hours, and then added to the hopper of the extruder, a variable cross-section double-lumen tube mold is selected, the extruder is started, and the extrusion parameters are set for extrusion, specifically:

[0027] The power supply is started, the swing cylinder 33 control switch spindle 59 is in the on state, the flow channel is on, the extrusion speed is set to 10-20 r / min, the cylinder on time is 0-120 s, the molten high molecular material fluid flows from the tearable double-lumen tube flow channel one 39 and the covering flow channel one 40, and then flows into the tearable double-lumen tube flow channel two 41 and the covering flow channel two 42, respectively, and then flows through the tearable double-lumen tube flow channel three 52, the covering flow channel three 54, and the covering flow channel four 53 to form an oblate ellipsoid covering double-lumen catheter, then the switch spindle 59 is in the off state, the flow channel two is on, the extrusion speed is set to 10-20 r / min, the cylinder off time is 0-120 s, and the molten particle fluid continues to flow from the tearable double-lumen tube flow channel one 39 into the tearable double-lumen tube flow channel two 41, and then flows through the tearable double-lumen tube flow channel three 52 to form a tearable double-lumen tube at the rear end of the oblate ellipsoid covering double-lumen catheter to obtain the main tube precursor;

[0028] S12, cutting of the main tube precursor: the main tube precursor obtained in step S11 is cut to 190-253 mm, and the main tube precursor includes an oblate ellipsoid covering double-lumen catheter portion with a length of 180-203 mm and a tearable double-lumen tube portion with a length of 10-50 mm;

[0029] S13, cutting of the main tube: first, the tearable double-lumen tube portion of the cut main tube precursor in step S12 is torn into two single-lumen tubes, then the main tube precursor is placed on a bevel cutting tool, after cutting off one single-lumen tube, the cutting angle is adjusted to be between 20° and 160°, and a stepped shape is cut to form a stepped bevel 25, and the angle between the bevel 25 and the single-lumen tube portion 23 is between 145° and 160°.

[0030] Further, the extrusion and cutting of the soft tip tube in step S2 mainly includes the following steps:

[0031] S21, soft head pipe body extrusion: select any one of the polyurethane elastomer, polyvinyl chloride, polypropylene, nylon elastomer with a shore hardness of 40A-85A, the polyurethane elastomer, polypropylene, nylon elastomer is dried by a dehumidifying dryer, dried for 4-6h, added to the hopper of the extruder, select single cavity pipe extrusion die, start the extruder, set the extrusion parameters to extrude the soft head pipe;

[0032] S22, soft head pipe cutting: cutting the soft head pipe body after extrusion to 1-3mm;

[0033] The extrusion parameters in step S21 are set as follows: cylinder zone one: 140-200 DEG C; cylinder zone two: 145-205 DEG C; cylinder zone three: 150-210 DEG C; flange: 145-205 DEG C; die head: 150-210 DEG C, and mold: 145-210 DEG C.

[0034] Further, the main pipe and the welding of the main pipe and the soft head pipe in step S3 do not include the following steps:

[0035] S31, melt head mold installation: rotate the mold locking knob 8 counterclockwise to move the upper mold fixed block 12 upward, place the fixed plane 17 of the melt head mold 14 in the groove one 28 of the lower mold fixed block 7, and then rotate the mold locking knob 8 clockwise, so that the upper mold fixed block 12 moves downward, and the fixed ring 15 of the melt head mold 14 is in the groove two 29 of the upper mold fixed block 12;

[0036] S32, welding: turn on the gas source and power switch, and adjust the appropriate air pressure; sequentially pass the main pipe cut in step S13 and the soft head pipe body cut in step S22 on the core needle, and tightly arrange the two parts; place the pipe body and the core needle into the melt head mold 14, and set the corresponding parameters to form the medical catheter.

[0037] The application further provides a medical catheter, which is a hemodialysis catheter, and the average breaking force of the hemodialysis catheter at the stepped section is between 160N and 180N.

[0038] The application has the following beneficial effects:

[0039] 1. The application provides a variable cross-section double-lumen tube mold for medical catheter forming, which comprises a flat-elliptical covered double-lumen catheter forming runner and a tearable double-lumen tube forming runner.

[0040] 2. This invention provides a variable cross-section double-lumen tube mold for medical catheter forming. The mandrel has two inner cavities, each with independently controlled airflow, resulting in good consistency of the inner diameter of the formed tube.

[0041] 3. This invention provides a stepped melting head device for conduits, which can realize the stepped shape of the conduit and the melting head at the head end in one step, avoiding the quality instability caused by two operations, resulting in good product consistency and significantly improved production efficiency.

[0042] 4. The present invention provides a stepped melting head device for a conduit. During the forming process, the welding parameters of the stepped part and the melting head part are controlled separately, which makes it easier to adjust and weld, resulting in a smooth and beautiful appearance after welding.

[0043] 5. The present invention provides a process for forming medical catheters using a variable cross-section double-lumen tube mold and a stepped melting head device. It is simple and easy to operate, requires no professional technicians, has low cost, low energy consumption, is non-toxic and odorless, and significantly improves production efficiency.

[0044] 6. The present invention provides a medical catheter, including a hemodialysis catheter, wherein the average breaking force at the stepped cross-section is between 160-180N. Attached Figure Description

[0045] To more clearly illustrate the technical solution of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Appendix Figure 1 This is a schematic diagram of a medical catheter.

[0047] Appendix Figure 2 This is a schematic diagram of the stepped structure of the main tube after stepped cutting.

[0048] Appendix Figure 3 This is a schematic diagram of the precursor of the main tube.

[0049] Appendix Figure 4 This is a three-dimensional schematic diagram of a variable cross-section double-cavity tube mold.

[0050] Appendix Figure 5 This is a cross-sectional view of a variable cross-section double-cavity tube mold.

[0051] Appendix Figure 6 for Figure 4 Enlarged view of section I in the middle.

[0052] Appendix Figure 7 This is a schematic diagram of the encapsulated flow divider.

[0053] AppendixFigure 8 This is a schematic diagram of the switch spindle and coupling.

[0054] Appendix Figure 9 This is a schematic diagram of the flow channel and its fluid distribution.

[0055] Appendix Figure 10 This is a cross-sectional view of the oscillating cylinder in the conductive state.

[0056] Appendix Figure 11 This is a cross-sectional view of the oscillating cylinder in the disengaged state.

[0057] Appendix Figure 12 This is a cross-sectional view of a flat, oval-shaped double-lumen catheter.

[0058] Appendix Figure 13 This is a cross-sectional view of a tearable double-lumen tube.

[0059] Appendix Figure 14 This is a structural diagram of a stepped melting head device.

[0060] Appendix Figure 15 Partial view of mold fixing.

[0061] Appendix Figure 16 This is a schematic diagram of the rectangular groove of the lower fixing block 7 of the mold.

[0062] Appendix Figure 17 This is a schematic diagram of the rectangular groove of the fixing block 12 on the mold.

[0063] Appendix Figure 18 This is a schematic diagram of the assembly of the melting head mold and the heating coil.

[0064] Appendix Figure 19 This is a cross-sectional view of the melting head mold.

[0065] In the diagram: 1 is the guide rail, 2 is the high-frequency power supply housing, 3 is the guide rail fixing clamp, 4 is the first heating coil, 5 is the heating coil fixing plate, 6 is the air blowing module, 7 is the lower fixing block of the mold, 8 is the mold locking knob, 9 is the locking knob fixing block, 10 is the melting head device fixing plate, 11 is the cooling port, 12 is the upper fixing block of the mold, 13 is the second heating coil, 14 is the melting head mold, 15 is the fixing ring, 17 is the fixing plane, 18 is the inner cavity, 18-1 is the inner cavity one, 18-2 is the inner cavity two, 22 is the double-cavity tube section, 23 is the single-cavity tube section, 24 is the flexible tube, 25 is the stepped slope, 28 is the groove one, 29 is the groove two, 30 is the flow channel distributor, 31 is the limit bolt, 32 is the coupling, 33 is the swing cylinder, 34 is the cylinder connecting plate, 35 is... Heat insulation plate 2, 36 is cylinder fixing plate, 37 is heat insulation plate 1, 38 is machine head body, 39 is tearable double-lumen tube flow channel 1, 40 is covered flow channel 1, 41 is tearable double-lumen tube flow channel 2, 42 is covered flow channel 2, 43 is fixing nut, 44 is rear pressure cover, 45 is tearable double-lumen tube flow divider, 46 is covered flow divider, 47 is positioning bolt, 48 is mandrel, 49 is die, 50 is die heating body, 51 is front pressure plate, 52 is tearable double-lumen tube flow channel 3, 53 is covered flow channel 4, 54 is covered flow channel 3, 55 is internal threaded hole of flow channel flow divider, 56 is countersunk hole on flow channel flow divider, 57 is circular through hole on mandrel, 58 is core needle, 59 is switch mandrel, 60 is hole on flow channel flow divider, 61 is through hole on switch mandrel. Implementation

[0066] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All mentioned embodiments are implemented based on the technical solutions of the present invention, and detailed implementation processes are given. However, it should be stated that the scope of protection of the present invention is not limited to the following embodiments.

[0067] The variable cross-section double-lumen die for medical catheter forming in this invention is used in the following embodiment for medical catheter extrusion:

[0068] This invention provides a variable cross-section double-lumen mold for medical catheter molding, such as... Figures 4-7 As shown, it mainly includes a swing cylinder 33, a flow channel distributor 30, a head body 38, a mandrel 48, a die 49, a covering flow divider 46, and a die heating element 50; the flow channel distributor 30 is provided with a tearable double-cavity tube flow channel 39 and a covering flow channel 40; the head body 38 is provided with a conical inner cavity penetrating the head body and tearable double-cavity tube flow channels 41 and covering flow channels 42 perpendicular to the conical inner cavity; the mandrel 48 and the die 49 form a covering flow channel 53, and the covering flow divider 46 and the die heating element 50 form a covering flow channel 54.

[0069] The core rod 48 and the covering shunt shuttle 46 form a tearable double-lumen tube flow channel three 52, which is in communication with the tearable double-lumen tube flow channel two 41, forming a tearable double-lumen tube forming flow channel two for the forming of the tearable double-lumen tube.

[0070] The mold also includes a tearable double-lumen tube shunt shuttle 45 that is in interference fit with the outer surface of the covering shunt shuttle 46 and the inner surface of the core rod 48, and the inner surface of the tearable double-lumen tube shunt shuttle 45 is in interference fit with the outer surface of the core rod 48. The tearable double-lumen tube shunt shuttle 45 is provided with a positioning hole on one side for placing a positioning bolt 47. The positioning bolt 47 and the positioning hole on one side of the core rod 48 are in mutual fit to realize the positioning of the core rod. The core rod 48 is provided with two circular through holes 57, which are respectively welded with two core needles 58 together for separately adjusting the size of the air intake to ensure the size consistency of the two inner holes after the product is formed.

[0071] The swing cylinder 33 in the mold is fixed on the cylinder connecting plate 34 through bolt connection, the cylinder connecting plate 34 is threadedly connected with the cylinder fixing plate 36 through the heat insulation plate two 35, and the cylinder fixing plate 36 is threadedly connected with the machine head body 38 through the heat insulation plate one 37. As shown in Figure 8 , the swing cylinder 33 drives and controls the on-off core shaft 59 through the shaft coupling 32, and the on-off core shaft 59 is connected with the flow channel shunt body 30 through the limiting bolt 31, which limits the position of the core shaft.

[0072] When the main tube is extruded, the power supply is started, as shown in Figure 10 , the swing cylinder 33 controls the on-off core shaft 59 to be in the on state, the flow channel one is turned on, the extrusion speed is set, the cylinder on time is set, and the molten polymer material fluid flows into the tearable double-lumen tube flow channel one 39 and the covering flow channel one 40, and then flows into the tearable double-lumen tube flow channel two 41 and the covering flow channel two 42, respectively, and then flows through the tearable double-lumen tube flow channel three 52, the covering flow channel three 54 and the covering flow channel four 53, respectively, to form an oblate ellipsoidal covering double-lumen catheter. Figure 11 , the on-off core shaft 59 is in the off state, the flow channel two is turned on, the extrusion speed is set, the cylinder off time is set, and the molten particle fluid continues to flow from the tearable double-lumen tube flow channel one 39 into the tearable double-lumen tube flow channel two 41, and then forms a tearable double-lumen tube at the rear end of the oblate ellipsoidal covering double-lumen catheter after passing through the tearable double-lumen tube flow channel three 52, to obtain a main tube precursor. The cross section of the oblate ellipsoidal covering double-lumen catheter is shown in Figure 12 , the cross section of the tearable double-lumen tube is shown in Figure 13 , and the schematic structure of the main tube precursor is shown in Figure 3 .

[0073] AsFigure 9 As shown, the flow channel 30 in the mold has an internal threaded hole 55 on the side near the extruder, which is threaded to the extruder through a connector; at the same time, it is threaded to the die head body 38 through four countersunk holes 56; a hole 60 is provided above for placing the switch spindle 59, and a through hole 61 perpendicular to the axis is provided on the switch spindle 59. The opening and closing of the covering flow channel 40 is controlled by rotating the direction of the through hole 61.

[0074] The die head 38 has four threaded holes parallel to the axis on one side near the die head, which are bolted to the die head heating body 50. On the other side, it has an internal threaded hole, which is threaded to the end of the rear pressure cover 44 with an external threaded hole. The other end of the rear pressure cover 44 has an internal threaded hole, which is connected to the fixing nut 43. The die head heating body 50 has an internal thread on one side, which is threaded to the front pressure plate 51 and presses the die head 49. The die head 49 is installed in the inner cavity of the die head heating body 50.

[0075] The stepped fusion head device for medical catheter forming in this invention is used for catheter body welding in the following manner:

[0076] The present invention also provides a stepped melting head device for medical catheter molding, such as... Figure 14 As shown, the device includes a heating coil assembly, a guide rail 1 for adjusting the overall position of the heating coil assembly 21, a high-frequency power supply housing 2 connected to the guide rail 1 by bolts and containing a high-frequency power supply module, a guide rail fixing clamp 3 for locking the heating coil assembly 21 and connected to the slider by threads, a heating coil fixing plate 5 with one end connected to the heating coil assembly by a joint or welding method and the other end welded to the high-frequency power supply housing 2, an air blowing module 6, a lower mold fixing block 7, a mold locking knob 8, a locking knob fixing block 9, an upper mold fixing block 12, a melting head device fixing plate 10 connected to the guide rail 1 by bolts, and a cooling port 11.

[0077] like Figure 18 As shown, the heating coil assembly includes heating coil one 4 and heating coil two 13. The parameters of heating coil one 4 are controlled to weld the single-cavity tube portion 23 of the main tube and the soft-head tube 24; the parameters of heating coil two 13 are controlled to weld the stepped inclined surface 25 of the main tube. The materials used for heating coil one 4 and heating coil two 13 both include copper wire with a wire diameter of 0.1-2mm and a pitch of 0.1-6mm.

[0078] like Figure 15 As shown, the locking knob fixing block 9 has a thread in the middle, and the mold fixing block 12 has a threaded hole in the middle; the mold locking knob 8 is connected to the mold fixing block 12 through the locking knob fixing block 9, and is used to fix the melting head mold 14.

[0079] The lower fixing block 7 of the mold has four threaded holes at its bottom, which are connected to the melting head device fixing plate 10 by bolts; it has two threaded holes at its top, which are connected to the locking knob fixing block 9 by bolts; it has four threaded holes at its upper left, which are connected to the air blowing module 6 by bolts; the air blowing module 6 has several mold cooling holes 11 for cooling. Figure 16 and Figure 17 As shown, a rectangular groove 28 is provided in the lower fixing block 7 of the mold, and a rectangular groove 29 is provided below the upper fixing block 12 of the mold. The positions of the first groove 28 and the second groove 29 are corresponding vertically and are used to place the melting head mold 14.

[0080] like Figure 18 As shown, one end of the melting head mold 14 is provided with a fixing ring 15, and the fixing ring 15 is provided with a fixing plane 17. The fixing plane 17 is installed in the groove of the lower fixing block 7 and the upper fixing block 12 of the mold; as Figure 19 As shown, the melting head mold 14 has an inner cavity 18 with the same shape as the tube body; the inner cavity 18 includes an inner cavity 18-1 with a stepped shape for placing the main tube and an inner cavity 18-2 for placing the soft head tube; the inner cavity 18-2 has a certain taper, wherein the taper on one side is 1°-5°.

[0081] During conduit forming, rotate the mold locking knob counterclockwise to move the upper mold fixing block upwards, placing the fixing plane of the fusion head mold in the first groove of the lower mold fixing block. Then, rotate the mold locking knob clockwise to move the upper mold fixing block downwards, positioning the fixing ring of the fusion head mold in the second groove of the upper mold fixing block, with the long axis of the forming perpendicular to the equipment installation. Turn on the air source and power switch, and adjust the appropriate air pressure. Insert the cut variable cross-section double-lumen tube and soft-head tube into the mandrel in sequence, ensuring they are tightly packed. Place the tube and mandrel into the mold, set the corresponding parameters, and begin welding. The stepped and soft-head sections are formed together, with parameters controlled separately for each section, resulting in a smoother tube forming effect and better bonding.

[0082] The specific implementation method of medical catheter forming using a variable cross-section double-lumen tube mold and a stepped melting head device in this invention is as follows:

[0083] The preparation of a medical catheter includes three steps: extrusion and cutting of the main tube, extrusion and cutting of the soft-tip tube, and preparation of the medical catheter, as detailed below:

[0084] Select any one of the following polymer materials with a Shore hardness of 60A-95A or 40D-60D: polyurethane elastomer, polyvinyl chloride, polypropylene, or nylon elastomer. Dry the polyurethane elastomer, polypropylene, or nylon elastomer in a dehumidifying dryer for 4-6 hours. Add the material to the extruder hopper, select a variable cross-section double-cavity die, start the extruder, and set the extrusion parameters for extrusion. Specifically:

[0085] When extruding the main tube, turn on the power supply, such as... Figure 10 As shown, the oscillating cylinder 33 controls the switch spindle 59 to be in the conducting state, thus opening the first flow channel and setting the extrusion speed; the cylinder conduction time; the molten polymer material fluid enters from the tearable double-lumen tube flow channel one 39 and the coating flow channel one 40, and then enters the tearable double-lumen tube flow channel two 41 and the coating flow channel two 42 respectively, passing through the tearable double-lumen tube flow channel three 52, the coating flow channel three 54 and the coating flow channel four 53 respectively, forming a flat elliptical coated double-lumen conduit; subsequently, as... Figure 11 As shown, the switch mandrel 59 is in the off state, flow channel two is open, and the extrusion speed and cylinder disconnection time are set. The molten granular fluid continues to flow from the tearable double-lumen tube flow channel one 39 into the tearable double-lumen tube flow channel two 41, and after passing through the tearable double-lumen tube flow channel three 52, a tearable double-lumen tube is formed at the rear end of the flat elliptical-covered double-lumen conduit, thus obtaining the main tube precursor. The cross-section of the flat elliptical-covered double-lumen conduit is shown below. Figure 12 As shown, the cross-section of the tearable double-lumen tube is as follows: Figure 13 As shown, the schematic structure of the main tube precursor is as follows: Figure 3 As shown.

[0086] The main tube precursor prepared in step S11 is cut to 190-253mm. The main tube precursor includes a flat oval covering double lumen conduit part with a length of 180-203mm and a tearable double lumen tube part with a length of 10-50mm.

[0087] First, the tearable double-lumen tube portion of the main tube precursor after cutting in step S12 is torn into two single-lumen tubes. Then, the main tube precursor is placed on the inclined cutting fixture. After cutting off one of the single-lumen tubes, the cutting angle is adjusted between 20° and 160° to perform stepped cutting and form a stepped inclined surface 25. The angle between the inclined surface 25 and the single-lumen tube portion 23 is between 145° and 160°.

[0088] S21, Flexible tube extrusion: Select any one of the following polymer materials with a Shore hardness of 40A-85A: polyurethane elastomer, polyvinyl chloride, polypropylene, and nylon elastomer. The polymer materials, such as polyurethane elastomer, polypropylene, and nylon elastomer, are dried in a dehumidifying dryer for 4-6 hours, added to the extruder hopper, a single-cavity tube extrusion die is selected, the extruder is started, and the extrusion parameters are set to extrude the flexible tube.

[0089] Cut the extruded soft-tip tube to 2mm.

[0090] S3, Medical Catheter Preparation: The main tube with its stepped bevel and single-lumen section are fused together with the soft-tipped tube using a stepped fusion device to obtain the medical catheter. Specifically:

[0091] clockwise rotation of the mold locking knob, the mold upper fixing block moves downward, and the fixing ring of the melt head mold is in the groove two of the mold upper fixing block, and the long axis direction of the formed is perpendicular to the equipment installation. Turn on the gas source and the power switch, and adjust the appropriate gas pressure; sequentially pass the cut variable cross-section double-lumen tube body and the soft tip tube body on the core needle, and tightly discharge them. Put the tube body and the core needle into the mold, set the corresponding parameters, and start the fusion. The stepped and soft head parts are formed together, the parameters of the two parts are controlled respectively, the tube body forming effect is smoother, and the bonding force is better. The parameters of the stepped position are set to prepare the medical catheter. And the quality of the medical catheter is detected.

[0092] Different materials are selected, different parameters are set, and the preparation of the medical catheter is as shown in the following table:

[0093]

[0094] The tube body prepared in the above examples has smooth appearance, no burr, no black spot, no fusion protrusion and the like, and the fracture force of the stepped part is tested according to the following test steps and the data is recorded. Compared with the conventional method of most stepped catheter forming processes on the market, that is, first extruding a double-lumen catheter, then extruding a single-lumen catheter, and fusing the double-lumen catheter and the single-lumen catheter together, the test results are shown in the following table.

[0095] The test steps include (1) fixing the measured catheter at the stepped part on the tensile tester, and using appropriate clamps to prevent injury; (2) measuring the gage length of the test section, that is, the distance between the clamps of the tensile tester. Adjust the gage length to 25 mm; (3) stretch at a rate of 500 mm / min until the test section separates into two sections; (4) record the fracture force of the catheter.

[0096]

[0097] As can be seen from the table, the fracture force of the catheter prepared by the preparation method provided by the application is greatly improved, the average fracture force of the stepped cross-section is between 160-180N, the double-lumen tube body and the single-lumen tube body are integrally formed in this way, the connection is firm, and the risk of fracture is avoided in the use process. And the variance and standard deviation of this forming method are small, indicating that the stability of the catheter forming is good.

[0098] The foregoing description of the disclosed embodiments enables a person skilled in the art to make or use the application. Modifications of these embodiments will occur to those skilled in the art and are within the scope of the following claims, defined solely by the words of the claims themselves, in which the patent is sought. Therefore, the application is not limited to the described embodiments and instead is intended to cover any and all modifications within the scope of the following claims.

Claims

1. A variable cross-section double lumen tube mold for medical catheter forming, characterized by, Mainly includes swing cylinder (33), flow channel shunt (30), head body (38), core rod (48), die (49), covering shunt shuttle (46) and die heating body (50), the flow channel shunt (30) inside is provided with tearable double lumen tube flow channel one (39) and covering flow channel one (40), the head body (38) inside is provided with the conical inner cavity that penetrates in head body and tearable double lumen tube flow channel two (41) and covering flow channel two (42) are vertically distributed with the conical inner cavity, the core rod (48) and the die (49) form covering flow channel four (53), and the covering shunt shuttle (46) and die heating body (50) form covering flow channel three (54), Wherein, the covering flow channel four (53), covering flow channel three (54) and covering flow channel two (42) are communicated, form the flow channel one of the forming of the flat elliptical covering double lumen catheter, for the forming of flat elliptical covering double lumen catheter, the core rod (48) and the covering shunt shuttle (46) form tearable double lumen tube flow channel three (52), and the tearable double lumen tube flow channel three (52) is communicated with the tearable double lumen tube flow channel two (41), forms the flow channel two of the forming of tearable double lumen tube, for the forming of tearable double lumen tube, the swing cylinder (33) is driven control to open and close core shaft (59) through coupling (32), and the open and close core shaft (59) is connected with flow channel shunt (30) through limiting bolt (31), and the limiting bolt (31) limits the position of core shaft.

2. The variable cross-section double lumen tube mold of claim 1, wherein, The swing cylinder (33) is fixed on the cylinder connecting plate (34) by bolt connection, the cylinder connecting plate (34) is threadedly connected with the cylinder fixed plate (36) through the heat insulation plate two (35), and the cylinder fixed plate (36) is threadedly connected with the head body (38) through the heat insulation plate one (37).

3. The variable cross-section double lumen tube mold of claim 1, wherein, The flow channel shunt (30) is provided with an internal thread hole (55) on the side close to the extruder, and is threadedly connected with the extruder through the connecting piece; meanwhile, four countersunk holes (56) are arranged, and the head body (38) is threadedly connected with the head body (38); a hole (60) for placing the open and close core shaft (59) is formed in the upper portion, a through hole (61) perpendicular to the axis direction is formed in the open and close core shaft (59), and the on-off of the covering flow channel one (40) is controlled by rotating the direction of the through hole (61).

4. The variable cross-section double lumen tube mold of claim 1, wherein, The head body (38) is provided with four thread holes parallel to the axis on the side close to the die, and is connected with the die heating body (50) through the bolt connection, and an internal thread hole is formed on the other side, and is threadedly connected with the one end of the external thread hole of the rear gland (44); the other end of the rear gland (44) is provided with an internal thread hole, and is connected with the fixed nut (43); one side of the die heating body (50) has an internal thread, and is threadedly connected with the front pressing plate (51) and presses the die (49) tightly; the die (49) is installed in the inner cavity of the die heating body (50).

5. The variable cross-section double lumen tube mold of claim 1, wherein, Also include the outer surface and the cladding shunt shuttle (46) inner surface interference fit, the inner surface and the core rod (48) outer surface interference fit tearable double cavity tube shunt shuttle (45), the said tearable double cavity tube shunt shuttle (45) one side is provided with positioning hole for placing positioning bolt (47); The positioning bolt (47) and the positioning hole on one side of the core rod (48) are matched with each other to realize the positioning of the core rod; The core rod (48) is provided with two circular through holes (57), and the circular through holes are welded with two core needles (58) respectively, which are used for separately adjusting the size of the air intake and ensuring the size consistency of the two inner holes after the product is formed.

6. A stepped die apparatus for forming a medical catheter, comprising: It includes a heating coil assembly, a guide rail (1) for adjusting the overall position of the heating coil assembly, a high-frequency power supply shell (2) connected with the guide rail (1) by bolts and having a high-frequency power supply module inside, a guide rail fixing clamp (3) for locking the heating coil assembly and connected with the sliding block by threads, a heating coil fixing plate (5) connected with the heating coil assembly by joint and welding at one end and welded with the high-frequency power supply shell (2) at the other end, a blowing module (6), a mold lower fixing block (7), a mold locking knob (8), a locking knob fixing block (9), a mold upper fixing block (12), a melting head device fixing plate (10) connected with the guide rail (1) by bolts, and a mold cooling hole (11); The heating coil assembly includes a heating coil one (4) and a heating coil two (13), the parameters of the heating coil one (4) are controlled to fuse the main tube single cavity tube part (23) and the soft head tube (24); The parameters of the heating coil two (13) are controlled to fuse the main tube stepped slope (25); The materials of the heating coil one (4) and the heating coil two (13) all include copper wire, the wire diameter of the copper wire is 0.1-2mm, and the pitch is 0.1-6mm.

7. The stepped tip device of claim 6, wherein, A thread is arranged in the middle of the locking knob fixing block (9), and a threaded hole is arranged in the middle of the mold upper fixing block (12); The mold locking knob (8) is connected with the mold upper fixing block (12) through the locking knob fixing block (9), and is used for fixing the melting head mold (14).

8. The stepped tip device of claim 6, wherein, Four threaded holes are arranged below the mold lower fixing block (7), and the mold lower fixing block (7) is connected with the melting head device fixing plate (10) through bolts; Two threaded holes are arranged above the mold lower fixing block (7), and the mold lower fixing block (7) is connected with the locking knob fixing block (9) through bolts; Four threaded holes are arranged above the left of the mold lower fixing block (7), and the mold lower fixing block (7) is connected with the blowing module (6) through bolts; The blowing module (6) has a plurality of mold cooling holes (11) for cooling.

9. The stepped tip device of claim 6, wherein, A rectangular groove one (28) is arranged in the mold lower fixing block (7), a rectangular groove two (29) is arranged below the mold upper fixing block (12), and the positions of the groove one (28) and the groove two (29) correspond to each other, and the melting head mold (14) is arranged in the groove one (28) and the groove two (29).

10. The stepped tip device of claim 9, wherein, One end of the melt head mold (14) is provided with a fixing ring (15), the fixing ring (15) is provided with a fixed plane (17), the fixed plane (17) is installed in the groove of the mold lower fixed block (7); The melt head mold (14) is provided with an inner cavity (18) which is the same as the shape of the pipe body; The inner cavity (18) includes an inner cavity one (18-1) for placing the main body pipe ladder type and an inner cavity two (18-2) for placing the soft head pipe; The inner cavity two (18-2) has a certain taper, wherein the single side taper is 1°-5°.

11. A process for forming medical catheters using a variable cross-section double-lumen mold and a stepped melting head device, characterized in that, Mainly including the following steps: S1, the extrusion and cutting of the main pipe: taking high molecular material as the main raw material, by selecting suitable extruder and controlling parameters, the main pipe is prepared by extrusion and cutting; The main pipe is ladder type, including double cavity pipe part (22) with length of 180-203mm, single cavity pipe part (23) with length of 10-50mm and ladder inclined plane (25); S2, the extrusion and cutting of the soft head pipe: taking high molecular material as the main raw material, by selecting suitable extruder and controlling parameters, the soft head pipe (24) is prepared by extrusion and cutting; The length of the soft head pipe (24) is 1-3mm; S3, the forming of the medical catheter: the main pipe ladder inclined plane (25) position and the single cavity pipe part (23) and the soft head pipe (24) are integrated by the ladder type melt head device to obtain the medical catheter; Wherein, the extrusion of the double cavity pipe part (22) and the single cavity pipe part (23) in step S1 is realized by using the variable cross section double cavity pipe mold for medical catheter forming according to any one of claims 1-5; The double cavity pipe part (22) is a flat elliptical covered double cavity catheter, and the single cavity pipe part (23) is prepared by cutting the tearable double cavity pipe; The flat elliptical covered double cavity catheter is obtained by flow channel one extrusion, and the tearable double cavity pipe is obtained by flow channel two extrusion; The catheter forming in step S3 is realized by using the ladder type melt head device for medical catheter forming according to any one of claims 6-10, and the melt welding parameters of the single cavity pipe part (23) and the soft head pipe (24) are as follows: heating power 70-100%, preheating 1-3s, heating 3-6s, advancing 7-12s, holding 1-8s, and cooling 10-16s; The forming parameters of the ladder inclined plane (25) position are as follows: heating power 70-100%, preheating 1-4s, heating 4-8s, advancing 7-12s, holding 3-10s, and cooling 10-18s.

12. The process of claim 11 wherein, The extrusion and cutting of the main pipe in step S1 mainly include the following steps: S11, the extrusion of the main pipe precursor: selecting any one of polyurethane elastomer, polyvinyl chloride, polypropylene and nylon elastomer with shore hardness of 60A-95A or 40D-60D, the polyurethane elastomer, polypropylene or nylon elastomer is dried by a dehumidifying dryer, dried for 4-6h, added to the hopper of the extruder, selected the variable cross section double cavity pipe mold, started the extruder, set the extrusion parameters for extrusion, specifically: The power supply is started, the swing cylinder (33) controls the switch core shaft (59) to be in the on state, the flow channel one and the flow channel two are turned on, the extrusion speed is set to 10-20 r / min, the cylinder is turned on for 5-120 s, the molten polymer material flows into the tearable double-cavity tube flow channel one (39) and the covering flow channel one (40), and then respectively enters the tearable double-cavity tube flow channel two (41) and the covering flow channel two (42), respectively passes through the tearable double-cavity tube flow channel three (52), the covering flow channel three (54) and the covering flow channel four (53), and forms an oblate covered double-cavity catheter; then, the switch core shaft (59) is in the off state, the flow channel two is turned on, the extrusion speed is set to 10-20 r / min, the cylinder is turned off for 1-120 s, and the molten particle flow continues to flow from the tearable double-cavity tube flow channel one (39) into the tearable double-cavity tube flow channel two (41), and then forms a tearable double-cavity tube at the rear end of the oblate covered double-cavity catheter after passing through the tearable double-cavity tube flow channel three (52), so as to obtain a main tube precursor; S12, cutting of the main tube precursor: the main tube precursor prepared in step S11 is cut to 190-253 mm, and the main tube precursor includes an oblate covered double-cavity catheter part with a length of 180-203 mm and a tearable double-cavity tube part with a length of 10-50 mm; S13, cutting of the main tube: first, the tearable double-cavity tube part of the main tube precursor cut in step S12 is torn into two single-cavity tubes, then the main tube precursor is placed on a bevel cutting tool, after one single-cavity tube is cut off, the cutting angle is adjusted to be between 20° and 160°, and a ladder-shaped cutting is performed to form a ladder bevel (25), and the included angle between the ladder bevel (25) and the single-cavity tube part (23) is between 145° and 160°.

13. The process of claim 12, wherein, The extrusion and cutting of the soft head tube in step S2 mainly include the following steps: S21, extrusion of the soft head tube: any one of polyurethane elastomer, polyvinyl chloride, polypropylene and nylon elastomer with a Shore hardness of 40A-85A is selected as a high polymer material, the polyurethane elastomer, polypropylene or nylon elastomer is dried by a dehumidifying dryer for 4-6 h, is added into an extruder hopper, a single-cavity tube extrusion die is selected, the extruder is started, and the extrusion parameters are set to extrude the soft head tube; S22, cutting of the soft head tube: the soft head tube after the extrusion is cut to 1-3 mm; In step S21, the extrusion parameters are set as follows: cylinder zone one: 140-200℃; cylinder zone two: 145-205℃; cylinder zone three: 150-210℃; Flange: 145-205℃; Head: 150-210℃, die: 145-210℃.

14. The process of claim 13, wherein, The forming of the medical catheter in step S3 includes the following steps: S31, melt head mold installation: counterclockwise rotation of the mold locking knob (8) to move the upper mold fixed block (12) upward, the fixed plane (17) of the melt head mold (14) is placed in the groove one (28) of the lower mold fixed block (7), and then clockwise rotation of the mold locking knob (8) to move the upper mold fixed block (12) downward, so that the fixed ring (15) of the melt head mold (14) is in the groove two (29) of the upper mold fixed block (12); S32, fusion: turn on the gas source and power switch, adjust the appropriate gas pressure; sequentially pass the main body tube cut off in step S13 and the soft head tube body cut off in step S22 on the core needle, tightly arrange the two parts; put the tube body and the core needle into the melt head mold (14), set the corresponding parameters to form the medical catheter.

15. A medical catheter prepared by the process according to claim 14, characterized in that, The average breaking force at the stepped cross-section of the hemodialysis catheter is between 160-180 N.

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