Preparation device for polytetrafluoroethylene two-color spiral tube blank, and method for extruding tube blank

Abstract

The present invention provides a preparation device for a polytetrafluoroethylene two-color spiral tube blank, and a method for extruding a tube blank. Mixed materials having different colors are added into the preparation device to be extruded to prepare semi-circular tube blanks having different colors, and the two semi-circular tube blanks having different colors are joined and combined to obtain a polytetrafluoroethylene two-color spiral tube blank, i.e., a two-color tube blank. The device comprises cylinder bodies, partition plates, and blocking plates; each cylinder body is a semi-circular cylinder, and a side plane of the semi-circular cylinder body is attached to the inner surface of the partition plate; two sides of the partition plate are provided with arc-shaped flanges extending parallel to the axis of the cylinder body, and the arc-shaped flanges are attached to the cambered surface of the cylinder body; the inner surface of the partition plate has a semi-cylinder coaxial with the cylinder body; a blocking plate is provided at one end of the cylinder body and the partition plate in the axial direction, and is configured to block a port of one end of an inner space defined by the inner surface of the cylinder body, the inner surface of the partition plate, and the outer cambered surface of the semi-cylinder.

Description

Preparation device for polytetrafluoroethylene two-color spiral tube blank and method for extruding the blank Technical Field

[0001] The invention relates to a device for preparing a polytetrafluoroethylene two-color spiral tube blank and a method for extruding the tube blank. Background Art

[0002] Polytetrafluoroethylene (PTFE) is a high-performance thermoplastic (also known as F4) that is widely used in medical heat shrink tubing due to its high temperature resistance, chemical solvent resistance, stable chemical properties, biocompatibility, non-stickiness, wide long-term use temperature range, and self-cleaning properties.

[0003] In recent years, interventional medicine, unlike traditional internal medicine and surgery, has gained widespread use. Physicians in interventional medicine rely on medical imaging equipment such as CT, MRI, and ultrasound to guide them through the lesions using specialized instruments such as catheters and guidewires. These instruments offer advantages such as minimal incision, high precision, and a wide range of indications. As a modern medical device, endoscopes are inserted through various natural cavities and minimally invasive procedures. Endoscope images are acquired through connection to imaging equipment or direct visual observation. Endoscopes are primarily used in areas such as the digestive system, urinary system, respiratory system, and gynecology. However, in interventional medicine, the time and scope of visualization are limited, making it difficult for attending physicians to accurately locate and quickly navigate internal tissues using cavities or other reference points. To address this issue, researchers and manufacturers have made numerous improvements to medical catheters, such as considering directly coating them. However, this approach makes it difficult to achieve long-term colorfastness and sustained color strength.

[0004] If the surface of a medical catheter has spiral stripes of two colors alternating with a certain pitch (i.e., a two-color spiral tube), it can be used in conjunction with an endoscope or other equipment to facilitate doctors to accurately locate and navigate internal tissues.

[0005] In the prior art, polytetrafluoroethylene (PTFE) tubes are typically formed by extrusion followed by subsequent sintering and other processes. In the extrusion device, a cylinder is fixed to the extrusion device frame. The extrusion port at the lower end of the cylinder communicates with the die cavity of the extrusion die. A core rod, which is immovable relative to the cylinder (for example, its lower end is fixed to the extrusion die), extends upward through the cylinder and passes through the piston and piston rod. The lower end of the piston rod is fixedly connected to the piston, while the upper end extends into the extrusion cylinder. The movement of the extrusion cylinder drives the piston rod up and down, allowing the piston to move in and out of the cylinder along the core rod.

[0006] During operation, the extrusion cylinder first drives the piston rod and piston upward, and the piston emerges from the upper end of the cylinder. Then, the mixture containing PTFE is added to the cylinder from the upper end of the cylinder. The extrusion cylinder then drives the piston rod and piston downward, and the piston enters the cylinder and moves downward along the core rod, extruding the mixture. The mixture is squeezed out of the lower end of the cylinder and enters the extrusion die cavity. After passing through the extrusion die cavity, it is formed into a prefabricated tube. The cylinder used in the pre-pressing process is mostly a single-cavity cylinder and cannot be disassembled. Only one color of tube blank can be pressed in this cylinder. Single-color blanks can only produce PTFE tubes of one color, which has certain limitations.

[0007] To produce a two-color PTFE spiral tube, a two-color tube blank is formed in a cylinder, which is then extruded to form a two-color preform tube. This is then followed by other steps to produce the two-color spiral tube. However, using existing PTFE tube extrusion equipment and methods, it is clearly impossible to produce a two-color tube blank or extrude a two-color preform tube. Summary of the Invention

[0008] The purpose of the present invention is to provide a preparation device for polytetrafluoroethylene two-color spiral tube blanks. Mixtures of different colors are added to the preparation device and extruded to produce semi-circular tube blanks of different colors. Two semi-circular tube blanks of different colors are combined to obtain polytetrafluoroethylene two-color spiral tube blanks, i.e., two-color tube blanks.

[0009] The preparation device of the polytetrafluoroethylene two-color spiral tube blank described in the present invention includes a cylinder body, a partition, and a blocking plate; the cylinder body is a semicircular ring, the side plane of the semicircular ring cylinder body is in contact with the inner surface of the partition, and arc-shaped flanges extending parallel to the axis of the cylinder body are provided on both sides of the partition, and the arc-shaped flanges are in contact with the arc surface of the cylinder body. A semi-cylinder coaxial with the cylinder body is provided on the inner surface of the partition, and a blocking plate is provided at one end in the axial direction of the cylinder body and the partition, which is used to seal one end port of the internal space surrounded by the inner surface of the cylinder body, the inner surface of the partition, and the outer arc surface of the semi-cylinder.

[0010] In the above-mentioned preparation device, the blocking plate is a semicircular plate that contacts the end face of the cylinder body, the end face of the semi-cylinder and the end face of the partition.

[0011] The above-mentioned preparation device is provided with a pressing block at the other end of the axial direction of the cylinder body and the partition. The pressing block is used to seal the other end port of the internal space. The pressing block can move along the axial direction of the cylinder body under the action of external force to compress the mixture in the internal space.

[0012] The above-mentioned preparation device has two cylinder bodies, two partitions, and two blocking plates. When the side plane of the cylinder body A is in contact with the side plane of the cylinder body B, they form an annular cylinder; it also includes a detachable connecting mechanism for connecting the cylinder body A and the cylinder body B that constitute the annular cylinder together and which can be removed from the annular cylinder.

[0013] In the above-mentioned preparation device, the detachable connection mechanism is a screw, which passes through the screw hole on the cylinder body A and is threadedly connected with the screw hole on the cylinder body B.

[0014] In the above-mentioned preparation device, the cylinder body A and the cylinder body B are connected by nuts and bolts passing through the bolt holes on the two cylinder bodies.

[0015] The above-mentioned preparation device has a card groove A on the outer surface of the cylinder body A, a card groove B on the outer surface of the cylinder body B, a transition connection half ring A has a card connection portion A extending into the card groove A, and a transition connection half ring B has a card connection portion B extending into the card groove B; the transition connection half ring A and the transition connection half ring B are connected in a detachable manner, and the transition connection half ring A and the transition connection half ring B have through holes for passing screws.

[0016] In the above-mentioned preparation device, the diameter of the cylinder is 30-120 mm and can be adjusted according to needs.

[0017] The above-mentioned preparation device has two separators, each with a thickness of 1-2 mm;

[0018] In the above-mentioned preparation device, the cylinder body is provided with 6 screw holes in total, which are staggeredly distributed.

[0019] In the above-mentioned preparation device, the transition connection half ring is provided with two screw holes.

[0020] In the above-mentioned preparation device, the cylinder body is made of stainless steel.

[0021] The present invention also provides a method for extruding tube blanks when preparing polytetrafluoroethylene two-color spiral tubes. The method comprises: detachably enclosing two semi-circular cylinder bodies with semi-circular tube blanks of different colors arranged therein to form a cylinder; detachably connecting the cylinder to a frame of an extrusion device; and driving a piston rod to move in the cylinder by an extrusion oil cylinder to extrude a two-color circular tube blank composed of two semi-circular tube blanks of different colors into the cylinder. The operation is efficient and quick.

[0022] The method for extruding a tube blank when preparing a polytetrafluoroethylene two-color spiral tube of the present invention uses the above-mentioned polytetrafluoroethylene two-color spiral tube blank preparation device, comprising the following steps:

[0023] 1) placing a semi-circular tube blank A into a semi-circular cylinder body A, and placing a semi-circular tube blank B into a semi-circular cylinder body B. The semi-circular tube blanks A and B have different colors. Both are non-loose semi-circular tube blanks obtained by applying a certain pressure to a mixture containing polytetrafluoroethylene and a color paste. The cylinder body A and the cylinder body B are butted and surrounded. The cylinder body A and the cylinder body B form a circular cylinder. The semi-circular tube blanks A and the semi-circular tube blanks B form a circular tube blank. A detachable connecting mechanism is used to connect the cylinder body A and the cylinder body B together. During butting and surrounding, a core rod in an extrusion device passes through the center of the circular tube blank. The cylinder is detachably connected to a frame of the extrusion device. A piston in the extrusion device is slidably arranged on the core rod, and the piston matches the cylinder.

[0024] 2) The extrusion device is activated, and the piston moves along the core rod in the cylinder to extrude the tube from the cylinder.

[0025] In the above-mentioned method for preparing polytetrafluoroethylene two-color spiral tube by extruding tube blank,

[0026] Preparation of semi-circular ring tube blank A: Assemble a cylinder body A and a partition together, with the side plane of the cylinder body A fitting the inner surface of the partition, and arc-shaped flanges extending parallel to the axis of the cylinder body provided on both sides of the partition, the arc-shaped flanges fitting the arc surface of the cylinder body, and a semi-cylinder coaxial with the cylinder body provided on the inner surface of the partition, and provide a blocking plate at one end in the axial direction of the cylinder body and the partition for blocking one end of the internal space surrounded by the inner surface of the cylinder body, the inner surface of the partition, and the outer arc surface of the semi-cylinder; Add a mixture A containing polytetrafluoroethylene and color paste A into the internal space; Use an auxiliary tool to apply a certain pressure to the mixture so that the mixture A in the internal space is shaped to form the semi-circular ring tube blank A, and remove the partition and blocking plate so that the semi-circular ring tube blank A does not become loose;

[0027] Using a method similar to the above, a mixture B containing polytetrafluoroethylene and color paste B is added into the inner surface of the cylinder body B, the inner surface of another partition, and the inner space surrounded by the outer arc surface of the semi-cylinder to prepare a semi-circular tube blank B:

[0028] The cylinder body A containing the semi-circular ring tube blank A and the cylinder body B containing the semi-circular ring tube blank B are butted and surrounded.

[0029] In the above-mentioned method for preparing polytetrafluoroethylene two-color spiral tube by extruding tube blank,

[0030] A slot A is formed on the outer surface of the cylinder body A, a slot B is formed on the outer surface of the cylinder body B, the transition connecting half ring A has a snap-fit ​​portion A that extends into the slot A, and the transition connecting half ring B has a snap-fit ​​portion B that extends into the slot B; the transition connecting half ring A and the transition connecting half ring B are connected in a detachable manner, and the transition connecting half ring A and the transition connecting half ring B have through holes for screws to pass through;

[0031] The clamping part A on the transition connection half ring A is extended into the clamping groove A, and the clamping part B on the transition connection half ring B is extended into the clamping groove B. The transition connection half ring A and the transition connection half ring B are connected in a detachable manner. The transition connection half ring A and the transition connection half ring B are connected to the frame of the extrusion device with transition connection screws.

[0032] In the above-mentioned method for preparing polytetrafluoroethylene two-color spiral tube by extruding tube blank,

[0033] A semi-annular groove A is provided on the outer surface of the cylinder body A, and a semi-annular groove B is provided on the outer surface of the cylinder body B. When the cylinder body A and the cylinder body B are butted together to form a cylinder, the semi-annular groove A and the semi-annular groove B form an annular groove on the cylinder; a stopper sleeve is also included, which is detachably connected to the cylinder and is used to prevent the stopper from coming out of the extrusion port of the cylinder; the stopper sleeve includes a front end plate, a rear stopper ring, and an intermediate body connecting the front end plate and the rear stopper ring; the front end plate, the rear stopper ring, and the intermediate body are all provided with an opening extending in the radial direction of the stopper sleeve, the width of the opening on the front end plate is consistent with the outer diameter of the core rod, the width of the opening on the rear stopper ring is consistent with the outer diameter of the annular groove, and the width of the opening on the intermediate body is not less than the outer diameter of the cylinder;

[0034] After step 1) and before step 2), there is step 1) in which two semicircular stoppers are inserted into the extrusion port of the cylinder away from the piston, the two semicircular stoppers surround the core rod to form a circular stopper; a stopper sleeve is inserted into the cylinder in a radial direction, the front end plate is located on the extrusion end face of the cylinder, and the rear stopper ring extends into the annular groove on the cylinder; the extrusion device is activated, the piston moves along the core rod in the cylinder, and the tube blank is squeezed toward the stopper to obtain a further compacted tube blank; then the stopper sleeve is removed from the cylinder, and the stopper is removed.

[0035] In the above-mentioned method for extruding a tube blank when preparing a polytetrafluoroethylene two-color spiral tube, the cylinder body A and the cylinder body B are threadedly connected by passing through a screw hole on one cylinder body and a screw hole on the other cylinder body.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. This patent proposes a device for preparing polytetrafluoroethylene two-color spiral tube blanks, which includes a cylinder body, a partition, a blocking plate, etc. Flanges are provided on both sides of the partition that can fit the arc surface of the cylinder body, and a raised semi-cylindrical structure is located in the middle of the partition. The flanges ensure that the partition will not separate from the cylinder body when the mixture is pre-pressed. At the same time, the flanges will not affect the axial movement of the partition relative to the cylinder body, making it easy to remove the partition. The blocking plate is a semi-circular plate with a simple structure and more convenient use. The use of a pressing block facilitates the pre-pressing of the mixture.

[0038] The semi-circular tube blank can be produced by using the production device. The semi-circular tube blank is taken out from the production device, and two semi-circular tube blanks of different colors are joined together to obtain a two-color tube blank.

[0039] When using two preparation devices, it is only necessary to separate the partition, blocking plate, etc. from the cylinder body, and there is no need to separate the semi-circular ring tube blank from the cylinder body. The two cylinder bodies are connected to form one cylinder, and at the same time, the two semi-circular ring tube blanks are connected to form a two-color circular ring tube blank. The cylinder is connected to the frame in a detachable manner, and the extrusion cylinder can be used to extrude the two-color tube blank, which greatly improves the operating efficiency.

[0040] The transition ring is formed by joining half ring A and half ring B, which are detachably connected to the frame, further improving the efficiency of connecting the cylinder to the frame. The connection between half ring A and half ring B also prevents the two cylinder bodies from separating.

[0041] 2. The preparation device is easy to clean, clean and hygienic, simple and efficient. The device and method can pre-press out two-color tube blanks with uniform color, and the junction of the two-color tube blanks is basically parallel to the axis of the tube blank.

[0042] 3. In conventional extrusion devices, the core rod passes through a monolithic cylinder, which cannot be disassembled, making it impossible to extrude two-color PTFE tubing. The extrusion method of the present invention utilizes two semi-circular cylinder bodies joined together to form a circular cylinder, and two semi-circular tube blanks joined together to form a circular tube blank. The presence of the core rod does not affect the joining of the two cylinder bodies or the two semi-circular tube blanks. Using a preparation device comprising a cylinder body, a partition, and a blocking plate, the preparation of semi-circular tube blanks is more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figures 1 and 2 are three-dimensional views of the cylinder body respectively;

[0044] Figures 3 and 4 are three-dimensional views of the partition respectively;

[0045] Figure 5 is a schematic diagram of the assembly of the partition plate, cylinder body, and pressure block;

[0046] FIG6 is a DD sectional view of FIG5;

[0047] FIG7 is a cross-sectional view taken along line EE of FIG5 ;

[0048] Figures 8 and 9 are perspective views of the cylinder body connected to the extrusion device;

[0049] FIG10 is a front view of the cylinder body and the like connected to the extrusion device in Example 1;

[0050] FIG11 is a cross-sectional view taken along line AA of FIG10 ;

[0051] FIG12 is a left side view of FIG10;

[0052] FIG13 is a cross-sectional view taken along line CC of FIG10 ;

[0053] Figures 14 and 15 are perspective views of the cylinder body and the extrusion device connected to Example 2;

[0054] Figures 16, 17 and 18 are three-dimensional views of the stopper sleeve respectively.

[0055] Explanation of the accompanying drawings: Cylinder body 1, partition 2, flange 21, semi-cylinder 22, blocking plate 3, pressure block 4, transition connection half ring 5, screw 6, cylinder body A11, cylinder body B12, cylinder 13, side plane 14, screw hole 15, screw hole 16, transition connection half ring A51, transition connection half ring B52, transition connection ring 53, clamping part A55, clamping part B56, transition connection screw 59, clamping groove A71, clamping groove B72, semi-circular ring tube blank A81, semi-circular ring tube blank B82, stopper sleeve 9, intermediate body 92, front end plate 91, rear stopper ring 93, semi-ring groove A95, semi-ring groove B96, ring groove 97, circular ring stopper 99, extrusion device 100, core rod 200, piston 300, frame 400, cylinder 500. DETAILED DESCRIPTION

[0056] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0057] Example 1:

[0058] 5-8, the preparation apparatus for a polytetrafluoroethylene two-color spiral tube blank includes a cylinder body 1, a partition plate 2, a plugging plate 3, a pressing block 4, a transition connection half ring 5, and a screw 6. The cylinder body 1, the partition plate 2, the plugging plate 3, the pressing block 4, and the transition connection half ring 5 are all two in number and have essentially the same structure.

[0059] The two cylinder bodies 1 are cylinder body A11 and cylinder body B12, and the two transition connection half rings 5 ​​are transition connection half ring A51 and transition connection half ring B52.

[0060] 1-4, the cylinder body 1 is a semicircular ring, and the side plane 14 of the semicircular ring cylinder body is in contact with the inner surface of the partition 2. Arc flanges 21 extending parallel to the axis of the cylinder body are provided on both sides of the partition. The arc flanges 21 are in contact with part of the arc surface of the cylinder body. A semi-cylinder 22 coaxial with the cylinder body is provided on the inner surface of the partition. A blocking plate 3 is provided at one end in the axial direction of the cylinder body and the partition. The blocking plate 3 is a semicircular plate in contact with the end face of the cylinder body, the end face of the semi-cylinder and the end face of the partition. The blocking plate 3 is fixed to one end of the partition 2 and is used to seal one end port of the internal space surrounded by the inner surface of the cylinder body, the inner surface of the partition and the outer arc surface of the semi-cylinder.

[0061] A pressure block 4 is provided at the other end of the cylinder body and the partition in the axial direction. The pressure block is used to seal the other end port of the internal space. The pressure block 4 can move along the axial direction of the cylinder body under the action of external force to compress the mixture including polytetrafluoroethylene in the internal space.

[0062] When the side plane of the cylinder body A11 and the side plane of the cylinder body B12 are fitted together, they can form an annular cylinder 13 .

[0063] A plurality of countersunk screw holes 15 and a plurality of through screw holes 16 are provided on the side planes 14 of the two cylinder bodies. The screw holes 15 on one cylinder body are opposite to the screw holes 16 on the other cylinder body. The screws 6 pass through the screw holes on one cylinder body and are threadedly connected to the screw holes on the other cylinder body, thereby detachably connecting the two cylinder bodies that constitute the cylinder.

[0064] A slot A71 is defined on the outer surface of one end of cylinder body A11, and a slot B72 is defined on the outer surface of one end of cylinder body B. Transition ring A51 has a snap-fit ​​portion A55 that extends into slot A, while transition ring B52 has a snap-fit ​​portion B56 that extends into slot B. The detachable connection between transition rings A and B is similar to that between the two cylinder bodies and will not be further described.

[0065] A semi-annular groove A95 is formed on the outer surface of the other end of the cylinder body A, and a semi-annular groove B96 is formed on the outer surface of the other end of the cylinder body B. When the cylinder bodies A and B are butted together to form a cylinder, the semi-annular groove A and the semi-annular groove B form an annular groove 97 on the cylinder.

[0066] The transition connection half ring A and the transition connection half ring B are provided with through holes for passing screws.

[0067] The method for extruding a tube blank when preparing a polytetrafluoroethylene two-color spiral tube comprises the following steps:

[0068] Referring to Figures 5-7 and 13, to prepare the semi-circular tube blank A81, the cylinder body A11 is inserted axially into the partition 2 until the blocking plate 3 seals the port at one end of the internal space defined by the inner surface of the cylinder body A, the inner surface of the partition, and the outer arc surface of the semi-cylinder. A mixture A containing polytetrafluoroethylene and colorant A is added to the internal space. A tool or a pressing block is used to apply pressure to the mixture, shaping it into the semi-circular tube blank A81. The tool or pressing block is then removed. The partition is pulled along the axis to separate it from the cylinder body A11, resulting in the cylinder body A11 containing the semi-circular tube blank A81.

[0069] Using a method similar to the above, a mixture B containing polytetrafluoroethylene and color paste B is added to the internal space surrounded by the inner surface of the cylinder body B, the inner surface of another partition, and the outer arc surface of the semi-cylinder to prepare a cylinder body B12 containing a semi-circular ring tube blank B82 inside.

[0070] Referring to Figures 8-13, cylinder body A, containing semi-circular tube A, and cylinder body B, containing semi-circular tube B, are joined together to form a cylinder. Semi-circular tubes A and B are joined together to form a circular two-color tube. During this joining process, core rod 200 in extrusion device 100 passes through the center of the circular tube. Screws 6 connect cylinder body A and cylinder body B.

[0071] The clipping portion A55 on the transition connecting half ring A51 extends into the clipping groove A71, and the clipping portion B56 on the transition connecting half ring B52 extends into the clipping groove B72. The transition connecting half ring A is connected to the transition connecting half ring B with a screw 6. The transition connecting half ring A and the transition connecting half ring B are connected to the frame 400 of the extruder with transition connecting screws 59 passing through the through hole. The piston 300 in the extruder is slidably set on the core rod 200, and the piston matches the cylinder.

[0072] The oil cylinder 500 in the extrusion device is activated, and the piston 300 moves along the core rod in the cylinder barrel 13 to extrude the two-color tube blank from the cylinder barrel.

[0073] The diameter (inner diameter) of the cylinder is 30 mm, and the thickness of the partition 2 is 1.5 mm. Each cylinder body is provided with 6 screw holes, which are staggered. The cylinder body is made of stainless steel.

[0074] Example 2:

[0075] The main difference between Example 2 and Example 1 is that, as shown in Figures 14-15, Example 2 further includes a circular stopper 99 formed by the joining of two semicircular stoppers, and a stopper sleeve 9 detachably connected to the cylinder. As shown in Figures 16-18, the stopper sleeve 9 includes a front end plate 91, a rear stopper ring 93, and an intermediate body 92 connecting the front end plate and the rear stopper ring. The front end plate, the rear stopper ring, and the intermediate body all have openings extending in the radial direction of the stopper sleeve. The width of the opening on the front end plate 91 is consistent with the outer diameter of the core rod 200, the width of the opening on the rear stopper ring 93 is consistent with the outer diameter of the annular groove 97, and the width of the opening on the intermediate body 92 is consistent with the outer diameter of the cylinder.

[0076] During use, first clean the two partitions 2 and briquette 4, disassemble the assembled cylinder, assemble the first partition 2 and the main body of the cylinder in sequence, add the color A mixture, install the briquette, and then use auxiliary tools to apply a certain amount of pressure to shape the internal mixture. Remove the partitions and briquette to prevent the material from loosening, and obtain a barrel body with semi-compacted material. Then, follow the same method as above to obtain a barrel body with semi-compacted material of the other color. Securely connect the cylinder bodies with the two semi-compacted colors of material with screws, and use two screws to secure the transition connecting half ring 5 to the frame, and install the screw in the middle.

[0077] Referring to Figures 14-15 and Figures 8-13, two semicircular stoppers are inserted into the extrusion port of the cylinder 13, away from the piston. The two semicircular stoppers surround the core rod 200 to form a circular stopper 99. The stopper sleeve 9 is inserted radially into the cylinder 13, with the front end plate 91 positioned at the extrusion end face of the cylinder and the rear stopper ring 93 extending into the annular groove 97 on the cylinder. The hydraulic cylinder is activated, and the piston moves along the core rod within the cylinder, squeezing the tube toward the stopper to further compact the tube. The two-color tube is uniform in color, with the intersection of the two colors substantially parallel to the axis, providing a foundation for the subsequent preparation of uniformly colored two-color spiral heat shrink tubing. The stopper sleeve 9 is then removed from the cylinder 13, and the stopper is removed.

[0078] Connect the extrusion die to the extrusion end of the cylinder, start the hydraulic cylinder, and the piston moves along the core rod in the cylinder to extrude the tube blank from the cylinder into the extrusion die cavity for the subsequent polytetrafluoroethylene two-color spiral tube preparation process.

[0079] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that any modifications and improvements made by a person skilled in the art without departing from the spirit of the present application are within the scope of protection of the present application.

Claims

1. A device for preparing polytetrafluoroethylene two-color spiral tube blanks, characterized by: It includes a cylinder body, a partition and a blocking plate; the cylinder body is a semicircular ring, the side plane of the semicircular cylinder body is in contact with the inner surface of the partition, arc-shaped flanges extending parallel to the axis of the cylinder body are provided on both sides of the partition, the arc-shaped flanges are in contact with the arc surface of the cylinder body, and a semi-cylinder coaxial with the cylinder body is provided on the inner surface of the partition. A blocking plate is provided at one end in the axial direction of the cylinder body and the partition, which is used to seal one end port of the internal space surrounded by the inner surface of the cylinder body, the inner surface of the partition and the outer arc surface of the semi-cylinder.

2. The preparation device according to claim 1, characterized in that: The blocking plate is a semicircular plate that contacts the end face of the cylinder body, the end face of the semi-cylinder and the end face of the partition.

3. The preparation device according to claim 1, characterized in that: A pressure block is provided at the other end of the axis direction of the cylinder body and the partition, and is used to seal the other end port of the internal space. The pressure block can move along the axis direction of the cylinder body under the action of external force to compress the mixture in the internal space.

4. The preparation device according to claim 1, characterized in that: Two cylinder bodies, two partitions, and two blocking plates are provided. When the side plane of the cylinder body A is in contact with the side plane of the cylinder body B, an annular cylinder is formed. It also includes a detachable connecting mechanism for connecting the cylinder body A and the cylinder body B that constitute the annular cylinder together and can be removed from the annular cylinder.

5. The preparation device according to claim 4, characterized in that: The detachable connection mechanism is a screw, which passes through a screw hole on the cylinder body A and is threadedly connected to a screw hole on the cylinder body B.

6. The preparation device according to claim 4, characterized in that: A card groove A is opened on the outer surface of the cylinder body A, and a card groove B is opened on the outer surface of the cylinder body B. The transition connection half ring A has a card connection portion A extending into the card groove A, and the transition connection half ring B has a card connection portion B extending into the card groove B; the transition connection half ring A and the transition connection half ring B are connected in a detachable manner, and the transition connection half ring A and the transition connection half ring B have through holes for passing screws.

7. A method for extruding a tube blank when preparing a polytetrafluoroethylene two-color spiral tube, characterized by: Using the preparation device according to claim 4, comprising the following steps: 1) placing a semi-circular tube blank A into a semi-circular cylinder body A, and placing a semi-circular tube blank B into a semi-circular cylinder body B, wherein the semi-circular tube blank A and the semi-circular tube blank B have different colors and are both non-loose semi-circular tube blanks obtained by applying a certain pressure to a mixture containing polytetrafluoroethylene and color paste; butting and enclosing the cylinder body A and the cylinder body B, the cylinder body A and the cylinder body B form a circular cylinder, and the semi-circular tube blank A and the semi-circular tube blank B form a circular tube blank, and a detachable connecting mechanism is used to connect the cylinder body A and the cylinder body B together; when butting and enclosing, a core rod in an extrusion device passes through the center of the circular tube blank; the cylinder is detachably connected to a frame of the extrusion device; a piston in the extrusion device is slidably arranged on the core rod, and the piston matches the cylinder; 2) The extrusion device is activated, and the piston moves along the core rod in the cylinder to extrude the tube from the cylinder.

8. The method for extruding a tube blank when preparing a polytetrafluoroethylene two-color spiral tube according to claim 7, characterized in that: Preparation of semi-circular tube blank A: Assemble a cylinder body A and a partition together, with the side plane of the cylinder body A fitting the inner surface of the partition, and add a mixture A containing polytetrafluoroethylene and color paste A into the inner space; use auxiliary tools to apply a certain pressure to the mixture so that the mixture A in the inner space is shaped into a semi-circular tube blank A, remove the partition and the blocking plate, and the semi-circular tube blank A is not loose; Using a method similar to the above, a mixture B containing polytetrafluoroethylene and color paste B is added into the inner surface of the cylinder body B, the inner surface of another partition, and the inner space surrounded by the outer arc surface of the semi-cylinder to prepare a semi-circular tube blank B: The cylinder body A containing the semi-circular ring tube blank A and the cylinder body B containing the semi-circular ring tube blank B are butted and surrounded.

9. The method for extruding a tube blank when preparing a polytetrafluoroethylene two-color spiral tube according to claim 7, characterized in that: A slot A is formed on the outer surface of the cylinder body A, a slot B is formed on the outer surface of the cylinder body B, the transition connecting half ring A has a snap-fit ​​portion A that extends into the slot A, and the transition connecting half ring B has a snap-fit ​​portion B that extends into the slot B; the transition connecting half ring A and the transition connecting half ring B are connected in a detachable manner, and the transition connecting half ring A and the transition connecting half ring B have through holes for screws to pass through; The clamping part A on the transition connection half ring A is extended into the clamping groove A, and the clamping part B on the transition connection half ring B is extended into the clamping groove B. The transition connection half ring A and the transition connection half ring B are connected in a detachable manner. The transition connection half ring A and the transition connection half ring B are connected to the frame of the extrusion device with transition connection screws.

10. The method for extruding a tube blank when preparing a polytetrafluoroethylene two-color spiral tube according to claim 7, characterized in that: A semi-annular groove A is provided on the outer surface of the cylinder body A, and a semi-annular groove B is provided on the outer surface of the cylinder body B. When the cylinder body A and the cylinder body B are butted together to form a cylinder, the semi-annular groove A and the semi-annular groove B form an annular groove on the cylinder; a stopper sleeve is also included, which is detachably connected to the cylinder and is used to prevent the stopper from coming out of the extrusion port of the cylinder; the stopper sleeve includes a front end plate, a rear stopper ring, and an intermediate body connecting the front end plate and the rear stopper ring; the front end plate, the rear stopper ring, and the intermediate body are all provided with an opening extending in the radial direction of the stopper sleeve, the width of the opening on the front end plate is consistent with the outer diameter of the core rod, the width of the opening on the rear stopper ring is consistent with the outer diameter of the annular groove, and the width of the opening on the intermediate body is not less than the outer diameter of the cylinder; After step 1) and before step 2), there is step 1) in which two semicircular stoppers are inserted into the extrusion port of the cylinder away from the piston, the two semicircular stoppers surround the core rod to form a circular stopper; a stopper sleeve is inserted into the cylinder in a radial direction, the front end plate is located on the extrusion end face of the cylinder, and the rear stopper ring extends into the annular groove on the cylinder; the extrusion device is activated, the piston moves along the core rod in the cylinder, and the tube blank is squeezed toward the stopper to obtain a further compacted tube blank; then the stopper sleeve is removed from the cylinder, and the stopper is removed.

Images