Plastic pipe with helical strip structure on outer surface and its preparation method

Abstract

The application discloses a plastic pipeline with spiral strip structure on the outer surface and a preparation method thereof, and comprises the following steps: mixing, hot stirring and cooling and stirring plastic pipeline raw materials to obtain a mixture; feeding the mixture into an extruder and extruding through a die to form a pipe blank with spiral strip structure; making the pipe blank pass through a rotating sizing sleeve assembly and being cooled and shaped in a water tank to obtain the plastic pipeline with spiral strip structure on the outer surface; synchronously rotating and dragging the plastic pipeline by using a rotating pipe dragging mechanism, and then performing length cutting; after cutting, the pipeline is corrected by a correction pipe supporting frame, is dragged by a two-jaw belt dragging machine, and is marked by code spraying, and then is packed into a warehouse to obtain the plastic pipeline with spiral strip structure on the outer surface. The application is a new type of dragging and rotating extrusion technology instead of a traditional die rotating extrusion technology, and the technology can realize long-term stable production and has a high production speed.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of pipes, in particular to a plastic pipe with a spiral strip structure on the outer surface and a preparation method thereof. BACKGROUND

[0002] A traditional preparation method of a plastic pipe with a spiral strip structure on the outer surface is realized by a rotating die through an external force to drive the rotating die, but this forming method needs to use bearings and sealing gaskets for sealing, and they are all in a high temperature environment (generally 170℃-210℃). In order to ensure the flowability of the material in the extrusion process, the die including the die is continuously heated. The bearing is easily stuck due to the rapid evaporation of lubricating oil, and the sealing gasket is also easily worn out due to the continuous rotation, which causes material leakage and leads to die sticking or large wall thickness deviation, thereby the quality is unstable. Generally, the production can only be maintained for 2-3 days before the bearing and gasket are replaced, the production cost is high, and the quality is difficult to maintain stable, especially the wall thickness will deviate and be uneven due to the wear of the gasket or the material leakage of the die.

[0003] At the same time, the rotating die is affected by the forming method, and the production speed of the electrician sleeve with a spiral strip structure on the outer surface is greatly reduced compared with the ordinary electrician sleeve, only 30%-40% of the production speed of the ordinary electrician sleeve, the production efficiency is low, thereby the cost is high, which is not conducive to the timely delivery of products and the improvement of market competitiveness. SUMMARY

[0004] Therefore, the present application aims to provide a plastic pipe with a spiral strip structure on the outer surface and a preparation method thereof to solve at least one technical problem in the background art.

[0005] To achieve the above-mentioned purposes, the technical scheme of the present application is as follows:

[0006] A preparation method of a plastic pipe with a spiral strip structure on the outer surface, comprising the following steps:

[0007] Mixing, hot stirring, temperature reduction and stirring of the plastic pipe raw material, and then standing to obtain a mixture;

[0008] The mixture is sent into an extruder and extruded through a die to form a pipe blank with a spiral strip structure;

[0009] The pipe blank passes through a rotating sizing sleeve assembly, and is cooled and shaped in a water tank to obtain a plastic pipe with a spiral strip structure on the outer surface;

[0010] The rotating pipe traction mechanism is used to rotate and pull the plastic pipe synchronously, and then the pipe is cut to a certain length;

[0011] The cut pipe is corrected by a correction pipe support, pulled by a two-jaw belt traction machine, and marked by a code marking device, and then is packaged and stored to obtain the plastic pipe with the spiral strip structure on the outer surface.

[0012] Further, the angle of the spiral strip in the die is 15-85°, and the number of the spiral strips is 6-35.

[0013] Further, the plastic pipe raw material is mixed, heated and stirred, cooled and stirred, and then is rested to obtain the mixture.

[0014] S1: weighing the plastic pipe raw material;

[0015] S2: adding the plastic pipe raw material into the stirrer, heating to 110-130℃, and starting the stirrer at the same time, the rotating speed of the rotating cylinder in the stirrer is 400-600r / min, and the hot stirring time is 10-25min;

[0016] S3: reducing the rotating speed of the rotating cylinder to 120-140r / min, cooling the mixed raw material to 35-45℃ at the same time, and the stirring time is 15-30min;

[0017] S4: after the raw material is uniformly mixed, resting for 5-8h to obtain the mixture.

[0018] A system for preparing a plastic pipe with a spiral strip structure on the outer surface, the system used in the method for preparing the plastic pipe with a spiral strip structure on the outer surface comprises, in sequence along the technological process:

[0019] an extrusion device comprising an extruder and a die arranged at the end of the extruder;

[0020] a sizing and cooling device comprising a water tank and at least one sizing sleeve assembly installed at the inlet of the water tank, the sizing sleeve assembly being configured to be driven to rotate by a power source;

[0021] a rotating traction device arranged downstream of the sizing and cooling device for synchronously rotating and pulling the pipe;

[0022] a cutting device arranged downstream of the rotating traction device for cutting the pipe;

[0023] a conveyor belt arranged downstream of the cutting device for conveying the cut pipe into a correction pipe support;

[0024] the correction pipe support arranged downstream of the conveyor belt, the correction pipe support comprising a base assembly, a plurality of transmission assemblies arranged side by side on the base assembly, and a power source assembly arranged on the base assembly;

[0025] a two-jaw belt traction machine arranged downstream of the correction pipe support;

[0026] and the inkjet printer and the packaging table.

[0027] Further, the sizing sleeve assembly is installed on the side wall of the water tank through a mounting bearing, the sizing sleeve assembly comprises a sizing sleeve and a first sprocket fixed thereon; a third sprocket is arranged on the output shaft of the power source; the system further comprises a transmission shaft, the transmission shaft is fixed with a second sprocket; the first sprocket, the second sprocket and the third sprocket are connected through a first chain.

[0028] The power source drives the third sprocket to rotate, the third sprocket drives the first chain to rotate, thereby driving the second sprocket and the first sprocket to rotate.

[0029] The base assembly comprises an upper base plate, a lower base plate, a support rod connected between the upper base plate and the lower base plate, and a support plate arranged on the upper base plate and the lower base plate.

[0030] Further, the transmission assembly comprises:

[0031] A bottom plate, which is provided with a recess and a through hole for accommodating the pipeline, and a plastic pipeline feeding horn is arranged at the feeding end of the bottom plate;

[0032] A first roller set and a second roller set are arranged on both sides of the bottom plate along the pipeline conveying direction respectively.

[0033] The first roller set comprises two symmetrically arranged first connecting plates, a first connecting shaft arranged between the two first connecting plates, and a first roller rotatably arranged on the first connecting shaft; the first connecting plate is provided with a first mounting groove for mounting the first connecting shaft.

[0034] Further, the power source assembly comprises:

[0035] A motor, the mounting end of which is mounted on a power source base, the power source base being arranged on the lower base plate, and the output end of the motor being provided with a fourth roller and a fourth sprocket;

[0036] A second connecting shaft, both ends of which are rotatably mounted on the support rod of the base assembly, the second connecting shaft being fixedly provided with a fifth sprocket and a plurality of sixth rollers;

[0037] A second chain connecting the fourth sprocket and the fifth sprocket;

[0038] The positions of the sixth rollers correspond to the positions of the through holes of the transmission assembly.

[0039] The power source assembly further comprises a second connecting plate, which is mounted between the power source base and the upper base plate.

[0040] Further, the correction cradle further comprises an upper pressing pipe assembly, which comprises:

[0041] An upper pressing pipe connecting plate is installed on one side of the upper base plate;

[0042] A first U-shaped connecting plate is arranged above the upper pressing pipe connecting plate at both ends;

[0043] At least one upper pressing roller unit is arranged on one side of the first U-shaped connecting plate;

[0044] The upper pressing roller unit comprises a power cylinder, a push plate, a second U-shaped connecting plate and a seventh roller; the cylinder body of the power cylinder is fixed, and the output end thereof is connected with the push plate; the second U-shaped connecting plate is arranged below the push plate; and the seventh roller is rotatably arranged on both sides of the second U-shaped connecting plate.

[0045] A plastic pipe with a spiral strip structure on the outer surface is prepared by using the preparation method of the plastic pipe with a spiral strip structure on the outer surface.

[0046] Further, the raw materials include, by weight: 100 parts of PVC resin, 5-20 parts of calcium powder, 3-8 parts of processing aids, 2-5 parts of impact modifiers, 3-5 parts of calcium-zinc stabilizers, 0.5-4 parts of colorants, 0.5-1 parts of stearic acid, and 0.5-1 parts of polyethylene wax.

[0047] And / or, the mounting bearing is a ceramic bearing;

[0048] The rotating pipe traction mechanism is a spiral staggered traction machine. The spiral staggered traction machine, also known as a "clamping type traction machine" or a "staggered wheel type traction machine", is a device that clamps and tractions continuous profiles (such as plastic plates and pipes) by staggering the arrangement of the upper and lower traction rollers (i.e. not directly aligned vertically).

[0049] Compared with the prior art, the plastic pipe with a spiral strip structure on the outer surface and the preparation method thereof have the following advantages:

[0050] 1. The present application solves the problem of product lettering by using a double traction machine, i.e. a rotating pipe traction mechanism and a traditional two-jaw belt traction machine, and adding a dynamic mobile code printing system between the two traction machines, and a correction cradle to realize the change from rotation to non-rotation after the electrical conduit is cut and formed.

[0051] 2. The present application relates to a preparation method of a plastic pipe with a spiral strip structure on the outer surface, which is a new type of traction rotation extrusion technology instead of traditional mouth mold rotation extrusion technology. This technology can realize long-term stable production, and the production speed can reach 1.5 to 2.5 times that of the mouth mold rotation technology, and the quality remains stable during long-term production. Attached Figure Description

[0052] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0053] Figure 1 This is a schematic diagram of the orifice as described in an embodiment of the present invention;

[0054] Figure 2 This is a schematic diagram of the side of the water tank according to an embodiment of the present invention;

[0055] Figure 3 This is a schematic diagram of the sizing sleeve assembly according to an embodiment of the present invention;

[0056] Figure 4 This is a schematic diagram of the orthodontic support frame described in an embodiment of the present invention;

[0057] Figure 5 This is a schematic diagram of the base assembly described in an embodiment of the present invention;

[0058] Figure 6 This is a schematic diagram of the first roller assembly according to an embodiment of the present invention;

[0059] Figure 7 This is a schematic diagram of the power source assembly described in an embodiment of the present invention (the second connecting plate is not shown).

[0060] Figure 8 This is a schematic diagram of the pressurized pipeline assembly described in an embodiment of the present invention.

[0061] Explanation of reference numerals in the attached figures:

[0062] 1, die; 2, water tank; 3, sizing bush assembly; 4, power source; 5, transmission shaft; 6, first chain; 7, first sprocket; 8, second sprocket; 9, third sprocket; 10, base assembly; 1011, upper base plate; 1012, support rod; 1013, lower base plate; 1014, support plate; 11, transmission assembly; 111, bottom plate; 112, first roller set; 113, second roller set; 114, plastic inlet pipe trumpet; 115, groove; 1121, first connecting plate; 1122, first connecting shaft; 1123, first roller; 1124, first mounting groove; 12, power source assembly; 1201, power source base; 1202, second connecting plate; 1203, second connecting shaft; 1204, motor; 1205, fifth sprocket; 1206, sixth roller; 1207, through hole; 1208, fourth roller; 1209, second chain; 1210, fourth sprocket; 13, upper pressing pipe assembly; 1301, upper pressing pipe connecting plate; 1302, first U-shaped connecting plate; 1303, power cylinder; 1304, push plate; 1305, second U-shaped connecting plate; 1306, seventh roller. DETAILED DESCRIPTION

[0063] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0064] The present application will be described in detail below with reference to the accompanying drawings and embodiments.

[0065] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise stated, the meaning of "a plurality of" is two or more.

[0066] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "linking" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0067] Example 1

[0068] Raw material processing: according to weight parts, take: PVC resin 100 parts, calcium powder 15 parts, processing aid 5 parts, impact modifier 3 parts, calcium zinc stabilizer 4 parts, colorant 1 part, stearic acid 0.8 part, polyethylene wax 0.8 part. The above raw materials are added into a high-speed mixer, heated to 120℃, and hot stirred at a speed of 500r / min for 15 minutes, so that the material is preliminarily plasticized and uniformly mixed. Subsequently, the rotating speed of the drum is reduced to 130r / min, and the material is cooled to 40℃ by cooling water, and continues to stir for 20 minutes. The uniformly mixed material is discharged and placed in a storage tank for 6 hours to obtain a cured mixture, which is ready for use.

[0069] Extrusion and spiral forming: the rested mixture is transported to the extruder. After being heated, melted and compacted in the extruder, the mixture is pushed to the head. The melted material is extruded through four die heads 1. As shown in Figure 1 , the inner wall of the die head 1 is processed with internal thread stripes, and the spiral angle is 45°, and the thread stripe number is 18. When the material passes through the die head 1, it is formed into a pipe blank with corresponding spiral stripe pattern on the surface.

[0070] Rotary sizing and cooling: the pipe blank with spiral stripe pattern immediately enters the water tank 2 for cooling and sizing. As shown in Figure 2 and Figure 3 , at the inlet of the water tank 2, a rotatable sizing sleeve assembly 3 is installed. The sizing sleeve assembly 3 is installed on the side wall of the water tank 2 through a bearing (preferably a ceramic bearing), and the inner hole shape of the sizing sleeve matches the outer diameter of the target pipe.

[0071] The power source 4 (in this example, a servo motor) is started, and through the third sprocket 9 on the output shaft, the first chain 6, the second sprocket 8 on the transmission shaft 5 and the first sprocket 7 on the sizing sleeve, the sizing sleeve is rotated at a set speed. The pipe blank is given a rotating force by the rotating sizing sleeve, and is rapidly cooled and sized in the cooling water of the water tank 2, forming a plastic pipe with accurate size and clear spiral stripe pattern.

[0072] Rotation traction and cutting: the shaped plastic pipe is continuously rotated and pulled out of the water tank 2 by the rotating pipe traction mechanism (in this case, a spiral staggered traction machine), ensuring that the spiral strip pattern is not damaged during the pulling process. The pipe then enters the cutting device for length cutting. After cutting, the pipe stops rotating.

[0073] Post-processing: the cut pipe enters the correction pipe holder for correction and transition, and then the main traction force is provided by the two jaw belt traction machines. Finally, the pipe is identified by the code spraying machine and then packaged into the warehouse.

[0074] The water tank 2 is provided with four pipe inlet ports on one side, and each port is provided with a set of the diameter setting sleeve assembly 3. The power source 4 drives the four sets of diameter setting sleeve assemblies 3 and the transmission shaft 5 to rotate synchronously through the first chain 6, ensuring the coordination of the production line. The water tank 2 is provided with a refrigeration device to provide efficient cooling effect.

[0075] Correction pipe holder: the correction pipe holder is the core component of the system for correcting, stabilizing and assisting in conveying the cut pipe. The base assembly 10 (see Figure 5 ): as the overall support frame, it is welded by the upper base plate 1011, the lower base plate 1013, four support rods 1012 and the support plate 1014 for reinforcement, and has a stable structure. The transmission assembly 11 (see Figure 4 、 Figure 6 ): a plurality of transmission assemblies 11 are installed side by side on the upper base plate 1011 of the base assembly 10. Each transmission assembly 11 has a bottom plate 111 provided with an arc-shaped groove 115 in the middle to hold the pipe and a through hole 1207. The inlet end is provided with a plastic pipe horn 114 for easy and smooth pipe feeding. The first and second roller groups 112 and 113 are arranged on both sides of the bottom plate 111 for guiding the pipe from both sides. The two first connecting plates 1121 of the first roller group 112 are symmetrically welded with inclined plates to better constrain the pipe. The first roller 1123 is installed in the first mounting groove 1124 through the first connecting shaft 1122, which is convenient for adjusting the position.

[0076] Power source assembly 12 (see Figure 7 ): the motor 1204 is installed on the lower base plate 1013 through the power source base 1201 and connected with the upper base plate 1011 through the second connecting plate 1202, which enhances the stability. The fourth roller 1208 at the output end of the motor 1204 drives the fifth sprocket 1205 through the second chain 1209, thereby driving the second connecting shaft 1203 to rotate. The second connecting shaft 1203 is fixed with a plurality of sixth rollers 1206, which are accurately positioned and aligned with the through holes 1207 on the bottom plate of the transmission assembly 11. The sixth roller 1206 partially protrudes from the through hole 1207 and directly contacts the bottom of the pipe, which drives the pipe to move forward through friction.

[0077] The upper pressing pipe assembly 13 (see Figure 8 ): The assembly is installed on the base assembly 10 through the upper pressing pipe connecting plate 1301. The power cylinder 1303 is fixed on the first U-shaped connecting plate 1302, and the piston rod thereof is connected to the push plate 1304 downward. The second U-shaped connecting plate 1305 is connected below the push plate 1304, and the seventh roller 1306 is installed on the second U-shaped connecting plate 1305 through a rotating shaft. When the pipe needs to be stabilized, the power cylinder 1303 acts to push the seventh roller 1306 downward to clamp the pipe together with the sixth roller 1206 below, prevent the pipe from jumping or deviating, and ensure stable conveying.

[0078] The rotating pipe traction mechanism is a spiral staggered traction machine. Four spiral staggered traction machines are arranged in the application and used for traction of four pipes. The four spiral staggered traction machines respectively traction the four pipes.

[0079] The spiral staggered traction machine adopts the prior art and is purchased from Zhongshan Zhongbang Plastic Machinery Co., Ltd. and has a model of ZB-008 spiral staggered traction machine.

[0080] The angle of the axial force roller of the rotating pipe traction mechanism is +6° to +10°.

[0081] The angle of the tangential force roller of the rotating pipe traction mechanism is -6° to -10.

[0082] The force of the axial force roller is responsible for pulling the pipe forward (realizing traction).

[0083] The force of the tangential force roller is responsible for rotating the pipe around its own axis.

[0084] The traction machine usually has two groups of upper and lower groups. The axis of the axial force roller and the pipe axis form a small positive angle (such as +6° to +10°). When the rollers rotate, the friction force generated by the rollers on the pipe can be decomposed into two directions: an axial force pulling the pipe forward and a tangential force rotating the pipe. The axis of the tangential force roller and the pipe axis form a negative angle (such as -6° to -10°). The friction force generated by the rollers is also decomposed into an axial pulling force (auxiliary traction) and an opposite tangential force.

[0085] Example 2

[0086] The preparation method of the plastic pipe with spiral strip structure on the outer surface comprises the following steps: mixing, hot stirring, and temperature reduction and stirring of the raw material of the plastic pipe, and then standing to obtain the mixture; feeding the mixture into an extruder, extruding through a die 1 to form a pipe blank with spiral strip structure; making the pipe blank pass through a rotating sizing sleeve assembly 3 and being cooled and shaped in a water tank 2 to obtain the plastic pipe with spiral strip structure on the outer surface; synchronously rotating and pulling the plastic pipe by using a rotating pipe pulling mechanism, and then cutting to a fixed length; after cutting, the pipe is conveyed by a conveyor belt, corrected by a correction pipe support, pulled by a two-jaw belt pulling machine, and marked by code marking, and then packed and stored to obtain the plastic pipe with spiral strip structure on the outer surface.

[0087] The angle of the spiral strip in the die 1 is 15-85°, and the number of thread strips is 6-35. The mixture obtained by mixing, hot stirring, and temperature reduction and stirring of the raw material of the plastic pipe after standing comprises the following steps:

[0088] S1: weighing the raw material of the plastic pipe;

[0089] S2: adding the raw material of the plastic pipe into a stirrer, heating to 110-130℃, and starting the stirrer at the same time, the rotating speed of the rotating cylinder in the stirrer being 400-600r / min, and the hot stirring time being 10-25min;

[0090] S3: reducing the rotating speed of the rotating cylinder to 120-140r / min, and at the same time, reducing the temperature of the mixed and stirred raw material to 35-45℃, and the stirring time being 15-30min;

[0091] S4: after the raw material is uniformly mixed, standing for 5-8h to obtain the mixture.

[0092] A preparation system of a plastic pipe with spiral strip structure on the outer surface, the system used in the preparation method of the plastic pipe with spiral strip structure on the outer surface comprises the following devices arranged in sequence along the process flow:

[0093] An extrusion device comprising an extruder and a die 1 arranged at the end of the extruder;

[0094] A sizing and cooling device comprising a water tank 2 and at least one sizing sleeve assembly 3 installed at the inlet of the water tank 2, the sizing sleeve assembly 3 being configured to be driven to rotate by a power source 4;

[0095] A rotating pulling device arranged downstream of the sizing and cooling device for synchronously rotating and pulling the pipe;

[0096] A conveyor belt arranged downstream of the cutting device for conveying the cut pipe into a correction pipe support;

[0097] A correction rack is arranged downstream of the conveying belt, the correction rack comprising a base assembly 10, a plurality of transmission assemblies 11 arranged side by side on the base assembly 10, and a power source assembly arranged on the base assembly 10.

[0098] A two-jaw belt traction machine is arranged downstream of the correction rack.

[0099] A code printer and a packaging table.

[0100] A sizing sleeve assembly 3 is arranged on the side wall of the water tank 2 through a mounting bearing, the sizing sleeve assembly 3 comprising a sizing sleeve and a first sprocket 7 fixed thereon; a third sprocket 9 is arranged on the output shaft of the power source 4; the system further comprises a transmission shaft 5, the transmission shaft 5 being fixed with a second sprocket 8; the first sprocket 7, the second sprocket 8 and the third sprocket 9 are connected through a first chain 6; the power source 4 drives the third sprocket 9 to rotate, the third sprocket 9 drives the first chain 6 to rotate, thereby driving the second sprocket 8 and the first sprocket 7 to rotate. The base assembly 10 comprises an upper base plate 1011, a lower base plate 1013, a support rod 1012 connected between the upper base plate 1011 and the lower base plate 1013, and a support plate 1014 arranged on the upper base plate 1011 and the lower base plate 1013.

[0101] The transmission assembly 11 comprises:

[0102] A bottom plate 111, which is provided with a recess 115 for accommodating a pipe and a through hole 1207, the feeding end of the bottom plate 111 being provided with a plastic pipe trumpet 114;

[0103] A first roller set 112 and a second roller set 113 are arranged on both sides of the bottom plate 111 along the pipe conveying direction respectively.

[0104] The first roller set 112 comprises two symmetrically arranged first connecting plates 1121, a first connecting shaft 1122 arranged between the two first connecting plates 1121, and a first roller 1123 rotatably arranged on the first connecting shaft 1122; the first connecting plate 1121 is provided with a first mounting groove 1124 for mounting the first connecting shaft 1122.

[0105] The power source assembly comprises:

[0106] A motor 1204, the mounting end of which is mounted on a power source base 1201 arranged on the lower base plate 1013, the output end of the motor 1204 being provided with a fourth roller 1208 and a fourth sprocket 1210;

[0107] A second connecting shaft 1203 is rotatably mounted at both ends on the support rod 1012 of the base assembly 10, and a fifth sprocket 1205 and a plurality of sixth rollers 1206 are fixed on the second connecting shaft 1203;

[0108] A second chain 1209 connects the fourth sprocket 1210 and the fifth sprocket 1205.

[0109] The positions of the sixth rollers 1206 correspond to the positions of the through holes 1207 of the transmission assembly 11.

[0110] The power source assembly further comprises a second connecting plate 1202, which is mounted between the power source base 1201 and the upper base plate 1011.

[0111] The correction cradle further comprises an upper pressing pipe assembly 13, which comprises:

[0112] An upper pressing pipe connecting plate 1301 is mounted on one side of the upper base plate 1011.

[0113] A first U-shaped connecting plate 1302 is arranged above the upper pressing pipe connecting plate 1301 at both ends.

[0114] At least one upper pressing roller unit is arranged on one side of the first U-shaped connecting plate 1302.

[0115] The upper pressing roller unit comprises a power cylinder 1303, a push plate 1304, a second U-shaped connecting plate 1305, and a seventh roller 1306. The cylinder body of the power cylinder 1303 is fixed, and the output end thereof is connected with the push plate 1304. The second U-shaped connecting plate 1305 is arranged below the push plate 1304, and the seventh roller 1306 is rotatably arranged on both sides of the second U-shaped connecting plate 1305.

[0116] A plastic pipe with a spiral strip structure on the outer surface is prepared by the preparation method.

[0117] The raw materials include, by weight: 100 parts of PVC resin, 5-20 parts of calcium powder, 3-8 parts of processing aids, 2-5 parts of impact modifiers, 3-5 parts of calcium-zinc stabilizers, 0.5-4 parts of colorants, 0.5-1 parts of stearic acid, and 0.5-1 parts of polyethylene wax.

[0118] The mounting bearing is a ceramic bearing.

[0119] The rotating pipe traction mechanism is a spiral staggered traction machine. The spiral staggered traction machine, also known as a "clamping type traction machine" or a "staggered wheel type traction machine", is a device that clamps and tractions continuous profiles (such as plastic plates and pipes) by staggered arrangement of the upper and lower traction rollers (i.e. not directly aligned vertically).

[0120] The preparation system is arranged in a straight line along the production flow direction of the plastic pipe, and each device is physically fixed and positioned by a rack, a guide rail or a connecting plate, so that the center line of the pipe is on the same straight line, thereby reducing the resistance and deviation of the pipe during operation.

[0121] The outlet of the die head 1 of the extrusion device is tightly connected with the inlet of the water tank 2 of the sizing and cooling device;

[0122] The distance between the outlet of the sizing and cooling device and the inlet of the rotating traction device is short, so that the spiral pattern is maintained. The outlet of the rotating traction device is connected with the inlet of the fixed-length cutting device through a light stainless steel guide groove, so that the pipe in rotation is constrained to accurately enter the cutting position. The single pipe after cutting enters the plastic pipe inlet horn 114 of the downstream correction pipe support frame through a conveyor belt.

[0123] The height of the conveyor belt corresponds to the height of the plastic pipe inlet horn of the downstream correction pipe support frame, and four grooves are arranged on the belt of the conveyor belt for the pipe, and the positions of the grooves correspond to the positions of the plastic pipe inlet horn. The positions of the grooves are accurately aligned with the plastic pipe inlet horn 114 of the correction pipe support frame, which can effectively prevent the pipe from rolling off during the transition stage. The conveyor belt runs at a speed close to the main flow of the production line, and smoothly sends the pipe into the guide horn of the correction pipe support frame.

[0124] The pipe is accurately guided into the correction pipe support frame through the conveyor belt. At this time, the pipe has completely left the rotating traction device, but it still has rotational inertia. The correction pipe support frame starts to work: the power source assembly 12 is started to drive the sixth roller 1206 to rotate, providing auxiliary forward power for the pipe, and at the same time, the pure rolling characteristic starts to consume the rotational kinetic energy of the pipe. The first roller group 112 and the second roller group 113 constrain the pipe from both sides to suppress its radial jumping and deviation.

[0125] According to the need, the power cylinder 1303 of the upper pressing pipe assembly 13 acts to push the seventh roller 1306 downward to clamp the pipe together with the sixth roller below. This further enhances the effect of braking rotation and prevents the pipe from jumping. Through the synergistic effect of multiple parallel transmission assemblies 11, the rotation of the pipe is gradually and smoothly suppressed, and finally changes to pure straight line motion at the end of the correction pipe support frame.

[0126] The end of the straightening cradle is seamlessly connected with the entrance of the two-jaw belt traction machine in space, ensuring that the straightened pipe can be immediately clamped. Behind the exit of the two-jaw belt traction machine, a code spraying machine and a packaging table are sequentially arranged. After the fixed-length cutting device, a straightening cradle, a two-jaw belt traction machine, a code spraying machine, and a packaging table are sequentially arranged. These devices are sequentially arranged, and the distance between adjacent devices is set according to the length of the pipe and the buffering needs, ensuring smooth transition of the pipe.

[0127] The extrusion speed, the rotating traction speed, and the two-jaw belt traction machine speed are closed-loop synchronously adjusted by the controller (using existing PLC technology), ensuring stable material flow. The straightening cradle provides auxiliary forward power, and its speed should match and be slightly lower than the main flow speed to avoid excessive stretching of the pipe, and its main function is to stabilize and straighten the pipe posture.

[0128] The existing PLC control system is used to uniformly coordinate the actions of each device, and the cooperative working process is as follows:

[0129] 1. Start and synchronize;

[0130] Start the entire system, and the extrusion device starts to work to extrude the pipe blank.

[0131] Initially manually introduce the pipe blank into the sizing and cooling device (the subsequent pipe blank is continuously output), and the power source 4 is started to drive the sizing sleeve to rotate, and at the same time, the water tank 2 starts to cool.

[0132] After the pipe head is introduced from the sizing and cooling device, the rotating traction device is started. Its traction speed matches the extrusion speed, and is closed-loop controlled by the control system to stabilize the wall thickness and diameter of the pipe. At the same time, the rotating speed of the rotating traction device is synchronized or proportional to the rotating speed of the sizing sleeve to ensure the continuity and consistency of the spiral stripes, and avoid the stripes being distorted or broken.

[0133] If the rotating sizing sleeve assembly 3 is not used, and only the die 1 with a spiral flow channel and the rotating traction are relied on, the pipe produced will face serious appearance and structure problems. The pipe blank with a preliminary spiral shape extruded from the die 1 is in a high-temperature molten state and has extremely low strength. At the moment of entering the cooling water tank 2, it will be affected by the impact force of the cooling water flow and its own gravity, and at the same time, it will be pulled by the rotating traction machine. This "pulling" action on the soft pipe blank will cause the spiral ribs on its surface to be twisted, shaken, and have uneven pitch. The rotating sizing sleeve assembly 3 acts as the first guiding and restraining device for the pipe blank after leaving the die 1.

[0134] 2. Rotating traction and fixed-length cutting;

[0135] The pipe is rotated and moved forward under the clamping of the rotating traction device. The pipe passes through the fixed-length cutting device. The control system measures according to the preset pipe length, and sends a signal to the cutting device when the set length is reached. The fixed-length cutting in the application is completed by a full-automatic chipless cutting machine (i.e. a non-stop cutting machine). After receiving the fixed-length cutting signal, the PLC instructs the chipless cutting machine to start. The cutting trolley accelerates until its moving speed is completely consistent with the pipe advancing speed. At the same time, the rotating clamping mechanism of the cutting machine synchronizes its angular speed with the rotation speed of the pipe. In the completely synchronized state: the clamp tightly holds the pipe, and the hydraulic cylinder quickly completes the shearing action.

[0136] The full-automatic chipless cutting machine adopts the existing technology, and the model is 250 type chipless cutting machine.

[0137] Since the whole process is completely synchronized, the cutting action is "static" to the pipe, so the cut is smooth and smooth, and does not interfere with the rotation and forward movement of the pipe itself. During the cutting process, the rotating traction device and the subsequent two-jaw belt traction machine maintain uniform speed to ensure continuous production line without stopping.

[0138] 3. Transition and correction from rotation to non-rotation;

[0139] The cut single pipe enters the correction pipe support through the conveyor belt. At this time, the pipe has been separated from the rotating traction device, and its rotational inertia is eliminated in the correction pipe support. The power source assembly of the correction pipe support starts to drive the sixth roller 1206 to rotate and provide auxiliary forward power for the pipe. The power cylinder 1303 of the upper pipe pressing assembly 13 can act as needed to make the seventh roller 1306 press down and jointly hold and stabilize the pipe with the sixth roller 1206, preventing it from jumping and deviating due to residual rotation or its own bending. The multiple transmission assemblies 11 work together to gradually correct the motion state of the pipe from "rotating forward" to "straight-line forward". The output speed of the correction pipe support is basically consistent with the speed of the two-jaw belt traction machine downstream.

[0140] After being pulled and cut by the spiral misalignment traction machine, the pipe is still in a rotating state, while the subsequent code spraying process requires the pipe to be non-rotating to ensure clear and accurate code spraying. The correction pipe support gradually suppresses and finally stops the rotation of the pipe through its multiple roller structures and the upper pipe pressing assembly 13, and smoothly transitions to a non-rotating state;

[0141] The pipe may bend, jump or deviate during transportation due to inertia, cooling shrinkage or uneven stress. The correction pipe support restrains and guides the pipe from both sides and above through the coordinated action of the first roller group 112, the second roller group 113 and the upper pressing roller unit, ensuring smooth transportation along a straight line.

[0142] The correction cradle drives the sixth roller 1206 from the bottom to contact the pipe through the power source assembly, providing friction force for forward conveying, assisting the two-jaw belt traction machine to complete the traction task, and avoiding pipe stagnation or skidding.

[0143] 4. Stable traction and subsequent processing;

[0144] The corrected pipe enters the two-jaw belt traction machine. The traction machine provides the main traction force of the production line, and its traction speed is strictly synchronized with the extrusion speed and the rotary traction speed to ensure the stability of the production line and the accuracy of the pipe size. Under the stable traction of the two-jaw belt traction machine, the pipe passes through the code jet without rotation, completing the identification printing. Finally, the pipe is conveyed to the packaging station for inspection and packaging.

[0145] The code jet uses a laser code jet. When the front end of the pipe (usually the cutting end) passes through the trigger sensor in front of the laser code jet, the sensor detects the pipe and sends a signal to the code jet.

[0146] The laser code jet uses existing technology, such as a small character continuous inkjet code jet or a fiber laser marking machine, specifically a small character code jet from WIDETEK. Since the pipe has been braked by the correction cradle during the code jet stage and is in a straight-line motion state without rotation and shaking, it provides an ideal "moving platform" for code jet, ensuring clear, unblurred, and unaltered characters.

[0147] The internal helical stripe in the die is between 15-85° to allow the extruder to extrude the material into a helical stripe, thereby improving production efficiency;

[0148] The four sizing sleeves are synchronously rotated by the motor installed under the water tank. To rotate smoothly, the sizing sleeve mouth is equipped with a ceramic bearing, which can effectively reduce the rusting and jamming caused by long-term production immersion;

[0149] To ensure the helical stripe effect on the outer surface, a refrigeration device can be added to the water tank to achieve rapid cooling, and the helical stripe effect will not be poor due to poor cooling or height not meeting the requirements.

[0150] To achieve pipe rotation, the first traction machine used is a helical staggered traction machine, similar to the principle of hand-twisted rope, which relies on the friction force and twisting motion of the upper and lower wheels to achieve the rotation of the outer surface of the electrical sleeve with a helical stripe structure, and the speed is adjustable and controllable.

[0151] Example 3

[0152] A plastic pipe with helical strip structure on the outer surface is produced by using environment-friendly formula. Specifically, 100 parts of PVC resin, 5-20 parts of calcium powder, 3-8 parts of processing aid, 2-5 parts of impact modifier, 3-5 parts of calcium-zinc stabilizer, 0.5-4 parts of colorant, 0.5-1 part of stearic acid, and 0.5-1 part of polyethylene wax are used.

[0153] A plastic pipe with helical strip structure on the outer surface comprises the following steps:

[0154] A, taking materials: respectively taking the raw materials in the formula;

[0155] B, high-speed hot stirring: adding the raw materials in the formula to the stirrer, heating the raw materials in the formula to 110-130℃, and starting the stirrer at the same time, the rotating speed of the rotating cylinder in the stirrer is 400-600r / min, and the hot stirring time is 10-25min;

[0156] C, low-speed cold stirring: reducing the rotating speed of the rotating cylinder to 120-140r / min, and cooling the stirred mixed raw materials to 35-45℃ at the same time, and the stirring time is 15-30min;

[0157] D, standing: after the raw materials are uniformly mixed, standing for 5-8h to obtain the mixed material, and storing in the storage tank;

[0158] E, forming: the mixed material is conveyed to the extruder for extrusion processing through the feeding system, first passing through a die with helical strip structure on the inner wall, the material becomes helical strip extrusion, then passing through a water tank cooling and sizing assembly, then passing through a helical staggered traction machine for synchronous rotation, then cutting to the required length, then passing through a conveyor belt, a straightening pipe rack and a non-rotating two-jaw belt traction machine to realize character spraying and marking, and finally packaging and storing in the warehouse;

[0159] F, extrusion process control: the production uses the extruder of Hebei Wanan Tongda Plastic Machinery Co., Ltd., which has good plasticizing performance, strong processing capacity, high automation degree, and the process parameters in the processing process are shown in Table 1.

[0160] Table 1 Process parameters in the processing process

[0161] ;

[0162] The whole production process is simple, the materials are fused better through high-speed thermal kneading, the temperature of the materials is reduced more uniformly through low-speed cold kneading, the whole material fusion is sufficient and pre-plasticized through the auxiliary role of standing, and the temperature is more consistent everywhere, thereby improving the quality of the pipe. In the extrusion process, the PVC mixed materials are continuously fully melted and plasticized through high-speed shearing and conveying of the extrusion screw, the screw continuously pushes the PVC mixed materials to the machine head when rotating in the cylinder, thereby achieving the purposes of compaction, melting, mixing, homogenization, degassing and dehydration. After extrusion, the material is vacuum sizing in the vacuum water tank with a refrigerator and a rotating sizing sleeve, and then the length meeting the requirements is cut after synchronous rotation of the spiral staggered traction machine, and then the marking is realized through the non-rotating conveying belt, correction support pipe rack and two-jaw belt traction machine, and finally the package is put into the warehouse.

[0163] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A system for preparing a plastic pipe with a spiral stripe pattern on its outer surface, characterized in that: Including those set sequentially along the process flow: An extrusion apparatus, including an extruder and a die located at its end; A sizing and cooling device includes a water tank and at least one sizing sleeve assembly installed at the inlet of the water tank, the sizing sleeve assembly being driven to rotate by a power source; A rotary traction device is located downstream of the sizing cooling device for synchronously rotating and traction of the pipe; A cutting device, located downstream of the rotary traction device, is used to cut pipes; The conveyor belt, located downstream of the cutting device, transports the cut pipes into the straightening support frame. A correction support frame is located downstream of the conveyor belt. The correction support frame includes a base assembly, a plurality of transfer components arranged side by side on the base assembly, and a power source assembly arranged on the base assembly. A two-claw belt traction machine is located downstream of the corrective support frame; And inkjet printers and packaging tables; The base assembly includes an upper base plate, a lower base plate, a support rod connecting the upper base plate and the lower base plate, and a support plate disposed on the upper base plate and the lower base plate. The transmission component includes: A base plate having grooves and through holes for accommodating pipes, wherein the feed end of the base plate has a flared opening for inlet plastic pipes; The first roller group and the second roller group are respectively arranged on both sides of the base plate along the pipeline conveying direction; The first roller assembly includes two symmetrically arranged first connecting plates, a first connecting shaft mounted between the two first connecting plates, and a first roller rotatably mounted on the first connecting shaft; the first connecting plates are provided with first mounting grooves for mounting the first connecting shaft. The power source assembly includes: The motor has its mounting end mounted on a power source base, which is located on the lower base plate. The output end of the motor is provided with a fourth roller and a fourth sprocket. The second connecting shaft is rotatably mounted at both ends on the support rod of the base assembly, and a fifth sprocket and a plurality of sixth rollers are fixedly mounted on the second connecting shaft; The second chain connects the fourth sprocket and the fifth sprocket; The position of the sixth roller corresponds to the position of the through hole in the transmission component; The power source assembly further includes a second connecting plate, which is installed between the power source base and the upper base plate. The orthodontic support also includes a pressure pipe assembly, which comprises: The upper pressure pipe connecting plate is installed on one side of the upper base plate; The first U-shaped connecting plate has its two ends positioned above the upper pressure pipe connecting plate; At least one pressure roller unit is disposed on one side of the first U-shaped connecting plate; The upper pressure roller unit includes a power cylinder, a push plate, a second U-shaped connecting plate, and a seventh roller; the cylinder body of the power cylinder is fixed, and its output end is connected to the push plate; the second U-shaped connecting plate is disposed below the push plate; and the seventh roller is rotatably disposed on both sides of the second U-shaped connecting plate.

2. The manufacturing system for a plastic pipe with a spiral stripe structure on the outer surface according to claim 1, characterized in that: The sizing sleeve assembly is mounted on the side wall of the water tank via a mounting bearing. The sizing sleeve assembly includes a sizing sleeve and a first sprocket fixed thereon. A third sprocket is provided on the output shaft of the power source. The system also includes a transmission shaft, on which a second sprocket is fixed. The first sprocket, the second sprocket, and the third sprocket are connected by a first chain. The power source drives the third sprocket to rotate, the third sprocket drives the first chain to rotate, which in turn drives the second sprocket and the first sprocket to rotate.

3. A method for preparing a plastic pipe with a spiral stripe pattern on its outer surface, using the preparation system for a plastic pipe with a spiral stripe pattern on its outer surface as described in claim 1 or 2, characterized in that: Includes the following steps: The raw materials for plastic pipes are mixed, heated, cooled and stirred, and then allowed to stand to obtain a mixture. The mixture is fed into an extruder and extruded through a die to form a tube blank with spiral stripes. The tube blank is passed through a rotatable sizing sleeve assembly and cooled and shaped in a water tank to obtain a plastic pipe with a spiral stripe pattern on the outer surface. The plastic pipe is synchronously rotated and pulled by a rotating tube traction mechanism, and then cut to a fixed length. After being cut, the pipes are straightened by a straightening support frame, pulled by a two-jaw belt traction machine, marked with inkjet printing, and then packaged and stored to obtain plastic pipes with a spiral stripe structure on the outer surface.

4. The method for preparing a plastic pipe with a spiral stripe structure on the outer surface according to claim 3, characterized in that: The angle of the spiral stripes in the die is 15 to 85°, and the number of threads is 6 to 35.

5. The method for preparing a plastic pipe with a spiral stripe structure on the outer surface according to claim 3, characterized in that: The process of mixing, hot stirring, and cooling stirring of plastic pipe raw materials, followed by standing, to obtain a mixture includes the following steps: Weighing the plastic pipe raw materials, adding them to a mixer, heating to 110-130℃, starting the mixer, rotating the drum at 400-600 r / min for 10-25 min, reducing the drum speed to 120-140 r / min, cooling the mixed materials to 35-45℃ for 15-30 min, and then letting it stand for 5-8 hours after mixing to obtain the mixture.

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