Long glass fiber composite pipe and production equipment and preparation method thereof

Abstract

The invention provides a long glass fiber composite pipe and production equipment and a preparation method thereof, the long glass fiber composite pipe comprises a plastic inner layer, a long fiber composite layer and a plastic outer layer which are sequentially connected from inside to outside, the combination surface of the plastic inner layer and the long fiber composite layer is of a tooth-shaped structure, and the combination surface of the plastic outer layer and the long fiber composite layer is of a tooth-shaped structure. One end of each long fiber composite pipe is provided with a pipeline connector used for connecting at least two long fiber composite pipes. The inner plastic layer and the outer plastic layer are each provided with the layer wall of the zigzag structure, so that the whole long glass fiber composite pipe is better formed, and the impact strength and the internal and external pressure resistance strength are improved. During production, through in-mold extrusion, cooling and shaping, the requirement for manufacturing a large-diameter and large-wall-thickness pipeline can be met, and the problem that the wall thickness of a pipe wall is not uniform due to sagging generated by a large-diameter and large-wall-thickness melt is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of pipelines, and in particular to a long glass fiber composite pipe; in addition, the present invention also relates to a production device for the long glass fiber composite pipe and a preparation method for the long glass fiber composite pipe. Background Art

[0002] The granular structure of short glass fiber reinforced plastic composite materials has too short fibers, and the proportion of glass fiber in the composite material is about 30%. The tensile strength of the material is about 25MPa, and the bending modulus is about 2000MPa. The reinforcement effect of the pipes made is not obvious, and the effect of reducing the pipe wall thickness and reducing costs cannot be achieved. At the same time, the impact toughness of the material is greatly reduced. Therefore, the pipes and fittings made are brittle, the pipe wall is thick, the cost is high, the compressive strength is low, and the effect of reducing wall thickness and increasing flow is poor, which cannot meet the requirements of large diameter, high pressure and ultra-high pressure. Summary of the invention

[0003] In order to solve the problems existing in the prior art, at least one embodiment of the present invention provides a long glass fiber composite tube, which greatly improves the impact strength and the internal and external pressure resistance, and reduces the tube wall thickness and pipeline cost. To this end, at least one embodiment of the present invention also provides a production device and a preparation method for a long glass fiber composite tube.

[0004] In the first aspect, an embodiment of the present invention proposes a long fiber composite tube, comprising a plastic inner layer, a long fiber composite layer and a plastic outer layer connected in sequence from the inside to the outside, the bonding surface between the plastic inner layer and the long fiber composite layer presents a toothed structure, the bonding surface between the plastic outer layer and the long fiber composite layer presents a toothed structure, the long fiber composite layer is made of a composite material with a glass fiber length of 2-20 mm, a glass fiber content of 10%-70%, and a plastic content of 30%-90%, and one end of the long fiber composite tube is provided with a pipe interface for connecting at least two long fiber composite tubes to each other.

[0005] In some embodiments, the present invention provides a long fiber composite tube, wherein the long fiber composite layer is welded to the plastic inner layer and the plastic outer layer respectively.

[0006] In some embodiments, the present invention provides a long fiber composite pipe, the pipe interface is provided with a sleeve pipe fitting which is socket-fused to the ends of multiple long fiber composite pipes, and the sleeve pipe fitting is provided with multiple sockets; the sleeve pipe fitting is made of a composite material with a glass fiber length of 2-20 mm, a glass fiber content of 10%-70%, and a plastic content of 30%-90%.

[0007] In some embodiments, the present invention provides a long fiber composite pipe, the pipe interface is provided with a pipe end butt-fusion joint, the outer wall of the pipe end butt-fusion joint is welded with a continuous glass fiber tape sleeve, and the continuous glass fiber tape sleeve is made of multi-layer winding and fusion of bidirectional continuous glass fiber tapes.

[0008] In some embodiments, the present invention provides a long fiber composite pipe, wherein the pipe interface is provided with a meshing self-locking opening, and a rubber sealing ring is provided on one side of the meshing self-locking opening.

[0009] In some embodiments, the present invention provides a long fiber composite pipe, wherein the pipe interface is provided with a beveled port butt-fusion interface.

[0010] In a second aspect, an embodiment of the present invention further provides an outer wall sizing production device for a long fiber composite tube, comprising:

[0011] At least two extruders arranged in parallel are connected to a cold ejection multi-layer co-extrusion circular composite mold. The multi-layer co-extrusion cold ejection composite mold is provided with a cooling constant temperature oil tank. The cooling constant temperature oil tank leads to the core mold of the inner plastic layer and the outer mold of the outer plastic layer through a back and forth pipeline.

[0012] A spray vacuum box is provided at the output end of the multi-layer co-extrusion cold ejection composite mold to further cool the long fiber composite tube after production;

[0013] A traction machine is arranged at the output end of the spray vacuum box and is used to traction the long fiber composite tube after production;

[0014] A cutting machine, arranged at the output end of the tractor, is used to cut the long fiber composite tube after production;

[0015] The support frame is arranged at the output end of the cutting machine and is used to support the cut long fiber composite tube.

[0016] In a third aspect, an embodiment of the present invention further provides a method for preparing the outer wall diameter of a long fiber composite tube, comprising:

[0017] Placing the plastic granules in the inner and outer layer extruders and the long glass fiber granules in the core layer extruder;

[0018] The temperature of each section of the inner and outer layer extruders and the core layer extruder is controlled at 180-250 degrees Celsius and the extrusion melt pressure is controlled at 100-150MPa, and the uniformly extruded plastic melt and long glass fiber melt are respectively placed in the co-extrusion mold cavity;

[0019] A long fiber composite tube composed of a plastic inner layer, a long fiber composite layer and a plastic outer layer is produced by a multi-layer co-extrusion cold ejection composite mold;

[0020] The outer mold and inner mold of the multi-layer co-extrusion composite mold are cooled and controlled to 60-110 degrees Celsius by cooling oil, and the inner and outer plastic walls are cooled and shaped under pressure in the mold cavity, generating a composite melt with smooth inner and outer tube walls coated with long glass fibers and ejected out of the cavity by strong pressure;

[0021] The composite melt with the inner and outer tube walls of the ejection cavity coated with long glass fibers is pulled into a cooling box for overall cooling to room temperature to form a long glass fiber composite tube, which is then cut into pieces according to a set length.

[0022] In a fourth aspect, an embodiment of the present invention further provides an inner wall sizing production device for a long fiber composite tube, comprising:

[0023] The crimping machine includes a driving machine, an inner mold roller and a bracket, and the inner mold roller is rotated at a certain angle;

[0024] The multi-layer co-extrusion flat-mouth die is arranged above the inner die roller side and is inclined at an angle to the cross section of the production line axis;

[0025] Extruders, at least two extruders are mounted on a bracket and connected to a multi-layer co-extrusion flat-mouth die;

[0026] The pressing rollers are arranged on the outside of the inner mold roller and parallel to the tube axis, the pressing rollers on the inner plastic layer are arranged on the inside of the inner mold roller and parallel to the tube axis, and the pressing rollers on the long glass fiber composite layer are arranged on the outside of the inner mold roller and perpendicular to the tube wall section;

[0027] A spray cooling water ring is provided at the output end of the inner mold roller to cool and shape the three-layer composite pipe body to generate a long fiber composite pipe;

[0028] A cutting machine, arranged at the output end of the spray cooling water ring, is used to cut the long fiber composite tube after production;

[0029] The tube collection table is arranged at the output end of the cutting machine and is used to collect the long fiber composite tubes after production.

[0030] In a fifth aspect, an embodiment of the present invention further provides a method for preparing the inner wall diameter of a long fiber composite tube, comprising:

[0031] Placing the plastic granules in the inner and outer layer extruders and the long glass fiber granules in the core layer extruder;

[0032] The temperature of each section of the inner and outer layer extruders and the core layer extruder is controlled at 180-250 degrees Celsius and the extrusion melt pressure is controlled at 100-150MPa, and the uniformly extruded plastic melt and long glass fiber melt are respectively placed in the co-extrusion mold cavity to form a three-layer tooth-shaped laminated composite melt;

[0033] The three-layer composite melt with toothed layers is stacked sideways at a certain inclination angle to form a tube wall thickness, thereby generating a three-layer long glass fiber composite tube melt;

[0034] The melt of the three-layer long glass fiber composite tube is pressed to form a three-layer tube wall, and the three-layer composite tube body is formed by demoulding according to the rotation angle of the inner mold roller;

[0035] The three-layer composite tube body is cooled and shaped to generate a long fiber composite tube, and the long glass fiber composite tube is cut according to a set length.

[0036] It can be seen that the long glass fiber composite tube and its production equipment and preparation method in the embodiment of the present invention respectively set the layer wall with a serrated structure in the plastic inner layer and the plastic outer layer, so as to better form the long glass fiber composite tube as a whole and improve the impact strength and the internal and external pressure resistance. During production, it is cooled and shaped by extrusion in the mold, so that it can meet the requirements of manufacturing large-diameter and large-walled pipes, and overcome the problem of uneven wall thickness caused by the sag of large-diameter and large-walled melt. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0038] Figure 1 Shown is a schematic structural diagram of a long fiber composite tube with a sizing of the outer tube wall in an embodiment of the present invention;

[0039] Figure 2 It is a schematic diagram showing the long fiber composite tubes connected to each other through sleeve pipe fittings in an embodiment of the present invention;

[0040] Figure 3 Shown is a schematic diagram of a three-way sleeve of a sleeve pipe fitting according to an embodiment of the present invention;

[0041] Figure 4 It is a schematic diagram showing the long fiber composite tubes connected to each other through the tube sleeves in an embodiment of the present invention;

[0042] Figure 5 It is a schematic diagram showing the long fiber composite tubes in an embodiment of the present invention connected to each other through a meshing self-locking opening;

[0043] Figure 6 It is a schematic diagram showing the long fiber composite tubes connected to each other through the bevel fusion joint in an embodiment of the present invention;

[0044] Figure 7 It is a schematic diagram showing that the long fiber composite layer for sizing the inner tube wall in an embodiment of the present invention is obliquely stacked, wound and fused.

[0045] The reference numerals in the accompanying drawings of the specification are as follows:

[0046] Plastic inner layer 1, long fiber composite layer 2, plastic outer layer 3, sleeve pipe fitting 4, pipe end butt welding joint 5, continuous glass fiber belt pipe sleeve 51, meshing self-locking mouth 6, rubber sealing ring 61, bevel end butt welding joint 7. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this article, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0049] [Example 1]

[0050] In the prior art, the short glass fiber reinforced plastic composite material with a granular structure has a fiber that is too short, and the glass fiber ratio in the composite material is about 30%. The tensile strength of the material is about 25MPa, and the bending modulus is about 2000MPa. The reinforcement effect of the manufactured pipe is not obvious, and the effect of reducing the pipe wall thickness and reducing costs is not achieved. At the same time, the impact toughness of the material is greatly reduced, so the manufactured pipes and pipe fittings are brittle, the pipe wall is thick, the compressive strength is low, and the effect of reducing the wall thickness and increasing the flow is poor, which cannot meet the use requirements of high pressure and ultra-high pressure. The embodiment of the present invention provides the following scheme:

[0051] like Figure 1As shown, an embodiment of the present invention provides a long fiber composite tube, comprising a plastic inner layer 1, a long fiber composite layer 2 and a plastic outer layer 3 which are sequentially connected from the inside to the outside, the bonding surface between the plastic inner layer 1 and the long fiber composite layer 2 is a tooth-like structure, the bonding surface between the plastic outer layer 3 and the long fiber composite layer 2 is a tooth-like structure, the long fiber composite layer is made of a composite material with a glass fiber length of 2-20 mm, a glass fiber content of 10%-70%, and a plastic content of 30%-90%, and one end of the long fiber composite tube is provided with a pipe interface for connecting at least two long fiber composite tubes to each other.

[0052] It should be noted that the long fiber composite tube is made of plastic and long glass fiber composite materials of the same crystal structure and is manufactured through an in-mold extrusion cooling and shaping process, that is, the plastic inner layer 1, the long fiber composite layer 2 and the plastic outer layer in the long fiber composite tube are manufactured by co-extrusion. The tooth structure can adopt a serrated structure, and the continuous serration increases the fusion area between the layers of the tube wall, which promotes a better formation of the composite tube as a whole, so as to improve the impact strength and internal and external pressure resistance of the composite tube. The long fiber composite tubes can be connected to each other through the pipe interface, thereby supporting the connection of multiple long fiber composite tubes.

[0053] In some embodiments, the long fiber composite layer 2 is welded to the plastic inner layer 1 and the plastic outer layer 3 respectively, so as to further ensure the stability of the long fiber composite tube.

[0054] In some embodiments, Figure 2 As shown, the pipeline interface is provided with a sleeve pipe fitting 4 which is socket-welded to the ends of a plurality of long fiber composite pipes, and the sleeve pipe fitting 4 is provided with a plurality of socket openings.

[0055] It should be noted that after one end of the two long fiber composite tubes are respectively inserted into the sleeve pipe fitting 4, the two long fiber composite tubes are connected to the sleeve pipe fitting 41 through capacitance or hot melting.

[0056] In some embodiments, the sleeve tube 4 is made of a composite material with a glass fiber length of 2-20 mm, a glass fiber content of 10%-70%, and a plastic content of 30%-90%.

[0057] It should be noted that sleeve pipe fittings with a wall thickness of 4-100 mm, such as elbow sleeves, flange sleeves, tee sleeves, straight sleeves, etc., are made by one-time injection molding by an injection molding machine. Figure 3 The shown figure is a three-way sleeve.

[0058] In some embodiments, Figure 4 As shown, the pipeline interface is provided with a pipe end butt-fusion joint 5, and a continuous glass fiber tape sleeve 51 is welded to the outer wall of the pipe end butt-fusion joint 5.

[0059] It should be noted that after the ends of the two long fiber composite pipes are respectively inserted into the continuous glass fiber tape sleeve 51, the two long fiber composite pipes are connected to the continuous glass fiber tape sleeve 51 through capacitance or hot melting. The continuous glass fiber tape sleeve 51 is more suitable for trenchless lining drag repair pipe repair, such as water supply, heating, drainage and other pipe networks.

[0060] In some embodiments, the continuous glass fiber tape tube sleeve 51 is made of bidirectional continuous glass fiber tapes that are wound and fused in multiple layers, thereby further increasing the impact strength and internal and external pressure resistance of the long fiber composite tube.

[0061] In some embodiments, Figure 5 As shown, the pipe interface is provided with a meshing self-locking port 6, and a rubber sealing ring 61 is provided on one side of the meshing self-locking port 6, so that the two long fiber composite pipes are sealedly connected through the meshing self-locking port 6. It is mainly used for repairing long glass fiber composite pipes with self-locking interfaces in the trenchless front-pull-back top process, such as drainage pipes.

[0062] In some embodiments, Figure 6 As shown, the pipe interface is provided with a beveled port butt-fusion joint 7, and the outer beveled pipe end of one end of a long fiber composite pipe is hot-melt-jointed with the inner beveled pipe end of another end of a long fiber composite pipe at the same angle. The beveled port butt-fusion joint 7 is more suitable for trenchless liner drag repair pipe repair, such as water supply, heating, drainage and other pipe networks.

[0063] In other embodiments, Figure 7 As shown, the long fiber composite tube is made of plastic and long glass fiber composite materials of the same crystal structure and is manufactured through an outside mold lamination cooling and shaping process. The long fiber composite layer 2 is obliquely stacked, wound and fused to the plastic inner layer 1 and the plastic outer layer 3. The long fibers use the outer diameter of the plastic inner layer 1 as the winding inner diameter, and the inclined surface is continuously stacked and fused to form the long fiber composite layer 2. The production equipment for producing the long fiber composite tube includes a pipeline rotating roller machine and a roller mold thereof; above the roller machine and the roller mold, a single screw extruder for manufacturing the plastic inner layer and a flat-mouth mold connected thereto and arranged parallel to the pipe axis are arranged;

[0064] A single screw extruder for manufacturing long glass fiber wound laminated pressure-resistant pipes, a flat-mouth mold with an inclination angle of 40-60° to the pipe axis, and a pressing wheel perpendicular to the inclination and with an internal cooling water jacket are arranged on the side front of the roller machine and its roller mold. The length-to-diameter ratio of the single screw extruder for the long glass fiber wound laminated pressure-resistant pipe is 36:1-42:1; a single screw extruder for manufacturing a plastic outer layer and a flat-mouth mold connected thereto and arranged parallel to the pipe axis are arranged at the front end of the single screw extruder for the long glass fiber wound laminated pressure-resistant pipe and the flat-mouth mold connected thereto; a spray cooling nozzle is arranged at the front end of the single screw extruder for manufacturing the plastic outer layer and the flat-mouth mold connected thereto; a rotating bracket is arranged at the front end of the spray cooling nozzle; a cutting machine is arranged at the front end of the rotating bracket; and a pipe receiving bracket is arranged at the front end of the cutting machine. The out-of-mold lamination cooling and shaping process is used, and the sheet melt is continuously wound, stacked, extruded and cooled. With the simplest molding process, the problem of uneven tube wall thickness caused by sag caused by large diameter and thick wall melt is overcome.

[0065] [Example 2]

[0066] The embodiment of the present invention also provides the outer wall sizing production equipment of embodiment 1, comprising:

[0067] At least two extruders arranged in parallel are connected to a cold ejection multi-layer co-extrusion circular composite mold. The multi-layer co-extrusion cold ejection composite mold is provided with a cooling constant temperature oil tank. The cooling constant temperature oil tank leads to the core mold of the inner plastic layer and the outer mold of the outer plastic layer through a back and forth pipeline.

[0068] It should be noted that the cold ejection multi-layer co-extrusion circular composite mold is equipped with an external cooling constant temperature oil tank, and the external cooling constant temperature oil tank is equipped with a cooling device and two independent inlet and outlet pipes, each of which is respectively connected to the outer mold and the core mold in the mouth mold, so as to achieve the controlled cooling temperature of the outer mold and the core mold at 50-110°C, and then achieve the three-layer co-extruded composite melt to form smooth inner and outer tube walls after pressure cooling and shaping in the mold, and then under the thrust of the extrusion force of the extruder screw melt, the tube body that has been cooled and shaped in the mold is ejected, and then the appearance requirements of smooth inner and outer walls of the tube body and smooth tube are achieved and met.

[0069] A spray vacuum box is provided at the output end of the multi-layer co-extrusion cold ejection composite mold to further cool the long fiber composite tube after production;

[0070] A traction machine is arranged at the output end of the spray vacuum box and is used to traction the long fiber composite tube after production;

[0071] A cutting machine, arranged at the output end of the tractor, is used to cut the long fiber composite tube after production;

[0072] The support frame is arranged at the output end of the cutting machine and is used to support the cut long fiber composite tube.

[0073] [Example 3]

[0074] The embodiment of the present invention also provides the outer wall sizing preparation method of embodiment 1, comprising:

[0075] Placing the plastic granules in the inner and outer layer extruders and the long glass fiber granules in the core layer extruder;

[0076] The temperature of each section of the inner and outer layer extruders and the core layer extruder is controlled at 180-250 degrees Celsius and the extrusion melt pressure is controlled at 100-150MPa, and the uniformly extruded plastic melt and long glass fiber melt are respectively placed in the co-extrusion mold cavity;

[0077] A long fiber composite tube composed of a plastic inner layer, a long fiber composite layer and a plastic outer layer is produced by a multi-layer co-extrusion cold ejection composite mold;

[0078] The outer mold and inner mold of the multi-layer co-extrusion composite mold are cooled and controlled to 60-110 degrees Celsius by cooling oil, and the inner and outer plastic walls are cooled and shaped under pressure in the mold cavity, generating a composite melt with smooth inner and outer tube walls coated with long glass fibers and ejected out of the cavity by strong pressure;

[0079] The composite melt with the long glass fiber coated on the inner and outer tube walls of the ejection cavity is pulled into a cooling box for overall cooling to room temperature to form a long glass fiber composite tube, which is then cut into pieces according to a set length.

[0080] [Example 4]

[0081] The embodiment of the present invention also provides the inner wall sizing production equipment of embodiment 1, comprising:

[0082] The crimping machine includes a driving machine, an inner mold roller and a bracket, and the inner mold roller is rotated at a certain angle;

[0083] The multi-layer co-extrusion flat-mouth die is arranged above the inner die roller side and is inclined at an angle to the cross section of the production line axis;

[0084] Extruders, at least two extruders are mounted on a bracket and connected to a multi-layer co-extrusion flat-mouth die;

[0085] The pressing rollers are arranged on the outside of the inner mold roller and parallel to the tube axis, the pressing rollers on the inner plastic layer are arranged on the inside of the inner mold roller and parallel to the tube axis, and the pressing rollers on the long glass fiber composite layer are arranged on the outside of the inner mold roller and perpendicular to the tube wall section;

[0086] A spray cooling water ring is provided at the output end of the inner mold roller to cool and shape the three-layer composite pipe body to generate a long fiber composite pipe;

[0087] A cutting machine, arranged at the output end of the spray cooling water ring, is used to cut the long fiber composite tube after production;

[0088] The tube collection table is arranged at the output end of the cutting machine and is used to collect the long fiber composite tubes after production.

[0089] [Example 5]

[0090] The embodiment of the present invention also provides the inner wall sizing preparation method of embodiment 1, comprising:

[0091] Placing the plastic granules in the inner and outer layer extruders and the long glass fiber granules in the core layer extruder;

[0092] The temperature of each section of the inner and outer layer extruders and the core layer extruder is controlled at 180-250 degrees Celsius and the extrusion melt pressure is controlled at 100-150MPa, and the uniformly extruded plastic melt and long glass fiber melt are respectively placed in the co-extrusion mold cavity to form a three-layer tooth-shaped laminated composite melt;

[0093] Driven by the crimping machine and its inner mold roller, the three-layer toothed composite melt is stacked at a certain inclination angle and then piled up into the tube wall thickness to generate a three-layer long glass fiber composite tube melt;

[0094] The melt of the three-layer long glass fiber composite tube is pressed under the pressure of the pressure roller to form a three-layer tube wall, and the three-layer composite tube body is demoulded by the rotation angle of the inner mold roller;

[0095] The three-layer composite tube body is cooled and shaped to generate a long fiber composite tube, and the long glass fiber composite tube is cut according to a set length.

[0096] In some embodiments, a co-extruded long glass fiber PE composite pipe with an inner diameter of 125 mm is prepared, and a HDPE-LFT (long glass fiber) raw material with a long glass fiber of 12 mm in length and 50% glass fiber content is used as a reinforcing material. A vacuum single screw extruder with a length-to-diameter ratio of 38:1 and a multi-layer co-extrusion die are used. The temperature of each section of the extruder and the die is controlled at 180-250 degrees Celsius, and the extrusion melt pressure is controlled at 100-150 MPa to produce a fused melt of a plastic inner layer, a core layer pressure-resistant pipe, and a plastic outer layer long glass fiber composite three-layer. The external cooling thermostatic oil tank is turned on to cool the inner and outer molds in the composite mold to 60-70°C, and the plastic inner layer and plastic outer layer are cooled under pressure in the composite mold to form a long glass fiber PE composite three-layer pipe body with smooth inner and outer walls. The pipe body with long fiber composite layer fused is fully cooled and shaped by vacuum spray cooling water tank and spray cooling water tank, and then produced by traction machine and cutting machine to produce composite pipe with 1.5mm thickness of plastic inner layer, 1.5mm thickness of plastic outer layer, 12mm thickness of core long glass fiber cylindrical tube, and 15mm total wall thickness of pipe, with nominal DN125mm×15mm, PN10.0MPa long glass fiber reinforced PE composite pipe. This long glass fiber reinforced PE composite pipe is mainly used for oil well pipe in oil field.

[0097] In some embodiments, a co-extruded long glass fiber PA composite pipe with an inner diameter of 200 mm is prepared, and a PA-LFT (long glass fiber) raw material with a long glass fiber of 12 mm in length and 50% glass fiber content is used as a reinforcing material. A vacuum single screw extruder with a length-to-diameter ratio of 38:1 and a multi-layer co-extrusion die are used. The temperature of each section of the extruder and the die is controlled at 200-280 degrees Celsius, and the extrusion melt pressure is controlled at 100-150 MPa to produce a fused melt of a plastic inner layer, a core layer pressure-resistant pipe, and a plastic outer layer long glass fiber composite three layers. The external cooling thermostatic oil tank is turned on to cool the inner and outer molds in the composite mold to 80-90 degrees Celsius, and the plastic inner layer and plastic outer layer are cooled under pressure in the composite mold to form a long glass fiber PA composite three-layer pipe body with smooth inner and outer walls. The long glass fiber PA composite 3-layer fused pipe body is fully cooled and shaped in a vacuum spray cooling water tank and a spray cooling water tank, and then produced by a traction machine and a cutting machine to produce a composite pipe with a plastic inner layer of 1.5mm thickness, a plastic outer layer of 1.5mm thickness, a core layer of long glass fiber cylindrical tube of 5mm thickness, and a total wall thickness of 8mm. The nominal DN200mm×8mm, PN2.0MPa long glass fiber reinforced PA composite pipe. The long glass fiber reinforced PA composite pipe is mainly used for transporting crude oil in oil fields.

[0098] In some embodiments, a co-extruded long glass fiber reinforced PE composite pipe with an outer diameter of 800 mm is prepared, and a HDPE-LFT (long glass fiber) raw material with a long glass fiber of 12 mm in length and 50% glass fiber content is used as a reinforcing material; a vacuum single screw extruder with a length-to-diameter ratio of 38:1 and a multi-layer co-extrusion die are used, and the temperature of each section of the extruder and the die is controlled at 180-250 degrees Celsius, and the extrusion melt pressure is controlled at 100-150 MPa to produce a fused melt of a plastic inner layer, a core layer pressure-resistant pipe, and a plastic outer layer long glass fiber composite three-layer. The external cooling thermostatic oil tank is turned on to cool the inner and outer molds in the composite mold to 60-70 degrees Celsius, and the plastic inner layer and plastic outer layer are cooled under pressure in the composite mold to form a long glass fiber composite three-layer pipe body with smooth inner and outer walls. The long glass fiber composite 3-layer fused pipe body is fully cooled and shaped in a vacuum spray cooling water tank and a spray cooling water tank, and then produced by a traction machine and a cutting machine to produce a composite pipe with a plastic inner layer of 1.5mm thickness, a plastic outer layer of 1.5mm thickness, a core layer of long glass fiber cylindrical tube of 10mm thickness, and a total wall thickness of 13mm. The nominal dn800mm×13mm, PN1.6MPa long glass fiber reinforced PE composite pipe. The long glass fiber reinforced PE composite pipe can be used for water supply pipe network, lining repair water supply, drainage pipes and other pipe networks with a use temperature below 30℃.

[0099] In some embodiments, a co-extruded long glass fiber reinforced PP composite pipe with an outer diameter of 800 mm is prepared, and a HPP-LFT (long glass fiber) raw material with a long glass fiber of 12 mm in length and 50% glass fiber content is used as a reinforcing material. A vacuum single-screw extruder with a length-to-diameter ratio of 38:1 and a multi-layer co-extrusion die are used, and the temperature of each section of the extruder and the die is controlled at 180-250 degrees Celsius, and the extrusion melt pressure is controlled at 100-150MPa to produce a fused melt of a plastic inner layer, a core layer pressure-resistant pipe, and a plastic outer layer long glass fiber composite three-layer. The external cooling constant temperature oil tank is turned on to cool the inner and outer molds in the composite mold to 60-70 degrees Celsius, and the plastic inner layer and plastic outer layer are cooled under pressure in the composite mold to form a long glass fiber composite three-layer pipe body with smooth inner and outer walls. The three-layer fused pipe body is fully cooled and shaped in a vacuum spray cooling water tank and a spray cooling water tank, and then produced by a traction machine and a cutting machine to produce a composite pipe with a plastic inner layer of 2mm thickness, a plastic outer layer of 2mm thickness, a core layer of long glass fiber cylindrical tube 12mm thickness, and a total wall thickness of 16mm. The nominal dn800mm×16mm, PN1.6MPa long glass fiber reinforced PP composite pipe. The long glass fiber reinforced PP composite pipe can be used for heat source heating and urban heating pipe network, oilfield sewage transportation, chemical medium transportation pipeline, lining repair heat source heating and urban heating pipe network, oilfield sewage transportation, chemical medium transportation pipeline and other pipe networks with a use temperature below 130 degrees Celsius.

[0100] In some embodiments, a laminated long glass fiber reinforced PE composite pipe with an inner diameter of 2000 mm is prepared, and a single screw extruder and a flat die for manufacturing a plastic inner layer are started to produce an inner layer plastic melt sheet with a width of 20 mm and a thickness of 15 mm. A roller machine with a roller outer diameter of 2000 mm is started to curl the inner layer plastic melt sheet, and a plastic inner layer with an inner diameter of 2000 mm, an overlap of 5 mm, and a winding width of 15 mm is manufactured, and the inner layer is continuously moved forward under the promotion of the helical angle of the roller machine. Start manufacturing long glass fiber winding and stacking pressure-resistant tube single screw extruder and its mold, produce long glass fiber melt with a width of 64mm and a thickness of 15mm, take the outer diameter of the plastic inner layer as the inner diameter, long glass fiber melt with a width of 64mm and a thickness of 15mm, drive the roller machine with a winding angle of about 60°, stack and wind the long glass fiber melt to melt and stick to the outer wall of the plastic inner layer, and manufacture long glass fiber winding and stacking pressure-resistant tube with a wall thickness of 55mm under external roller pressure, and continue to move forward under the drive of the roller machine spiral angle and the plastic inner layer. Start manufacturing plastic outer layer single screw extruder and flat-mouth mold, produce outer layer plastic melt sheet with a width of 20mm and a thickness of 15mm. Driven by the roller machine, curl the outer layer plastic melt sheet and melt it on the outer wall of the long glass fiber winding and stacking pressure-resistant tube, manufacture a plastic outer layer with a 5mm overlap and a winding width of 15mm, and continue to move forward under the drive of the roller machine spiral angle and the long glass fiber winding and stacking pressure-resistant tube. Open the cooling nozzle to cool and shape the long glass fiber laminated composite pipe, open the rotating bracket, and the auxiliary roller machine drives the long glass fiber laminated composite pipe to rotate at a constant speed. Open the cutting machine to cut and cool the long glass fiber reinforced PE composite pipe with DN2000mm×85mm, PN1.0MPa, and external pressure SN8.2MPa, with inner and outer wall thickness of 15mm and pressure-resistant layer thickness of 55mm.

[0101] In some embodiments, a long glass fiber reinforced PE elbow pipe fitting with an inner diameter of 800 mm is prepared, and a HPP-LFT (long glass fiber) raw material with a long glass fiber of 12 mm in length and 50% glass fiber content is used as a reinforcing material. A single screw injection molding machine is used, and the temperature of each section of the screw is controlled at 180-250 degrees Celsius, and the extrusion melt pressure is controlled at 100-110 MPa to produce a nominal 800 mm, PN2.0 MPa long glass fiber reinforced PE composite pipe fitting. The 90° elbow mold feed port is set at the top of the arc, and its flow channel is set in the shape of a three-point injection of the arc, the mold cavity thickness is set to 22 mm, the mold temperature is 60 degrees Celsius, the injection time is 40 seconds, the pressure holding time is 20 minutes, and the pressure holding pressure is above 20 MPa. The processing technology produces a finished product with an inner diameter of 801-802 mm, a wall thickness of 22 mm, a nominal 800 mm, and a PN2.0 MPa long glass fiber reinforced PE composite pipe fitting. The long glass fiber reinforced PE composite pipe fittings with a nominal length of 800mm and PN2.0MPa that have been injection molded are laid with resistance wires at the straight sections at both ends of the pipe fittings using a resistance wire wiring machine to generate long glass fiber reinforced PE composite electric fusion pipe fittings with a nominal length of 800mm and PN2.0MPa.

[0102] In some embodiments, a pipe interface with an outer diameter of 800 mm is prepared, and a clamp at one end of a hydraulic hot melt machine is used to clamp the pipe end of a long glass fiber reinforced PP composite pipe with a nominal dn of 800 mm × 16 mm and PN of 1.6 MPa, and the port pipe ring is wiped clean with an alcohol rag. A clamp at one end of a hydraulic hot melt machine is used to clamp a long glass fiber reinforced PP composite electric fusion pipe fitting with a nominal diameter of 800 mm and PN2.0 MPa. Under the push of a hydraulic press, the electric fusion pipe fitting is inserted into the composite pipe end to a depth of 40-50 mm. The electric fusion machine wire is connected to a resistance wire joint to control the temperature at 260 degrees Celsius and the power is turned on for 100-200 seconds and then turned off. The interface remains in a static state for more than 30 minutes, the clamp is removed, and the hydraulic hot melt machine is removed.

[0103] In some embodiments, a lined composite pipe is prepared to repair an existing DN600mm steel pipe for heating. The two ends of the produced long glass fiber reinforced PP composite pipe with an outer diameter of dn600mm×20mm and PN1.6MPa are cut into inner and outer inclined surfaces respectively, and the inclined surfaces are heated by a hot melt plate to be molten, and then the composite pipe with an outer diameter of 600mm is continuously extended under the action of a hot melt hydraulic press. The ground openings at both ends of the existing DN600mm steel pipe section to be repaired are inclined to the two ends of the steel pipe section, and the inner wall of the existing DN600mm steel pipe to be repaired is dragged and scraped by a torpedo head of a trenchless machine to remove scale and rust. The extended composite pipe with an outer diameter of 600mm is connected to the torpedo head of the trenchless machine, and under the dragging force of the trenchless machine, it is dragged while pressure-injecting water into the existing pipe, and the extended composite pipe with an outer diameter of 600mm is lined in the existing DN600mm steel pipe section to be repaired to form an inner-lined composite pipe repair pipe.

[0104] In some embodiments, a lined composite pipe is prepared to repair an existing DN600mm cement pipe for drainage, and a long glass fiber reinforced PE composite pipe with an outer diameter of 600mm×20mm and a thickness of SN=12.5KN / m2 that has been produced is cut into a length of 1 meter. The two ends of the 1-meter long glass fiber reinforced PE composite pipe are respectively machined into a socket, a spigot, a tooth layer, and a sealing ring groove of a flexible sealed self-locking socket, and a sealing ring is put on. The first long glass fiber reinforced PE composite pipe section is inserted into the DN600mm cement pipe with the spigot end in front and the spigot end in the back, and the long glass fiber reinforced PE composite pipe section is gradually lined under the joint action of the front traction machine and the traction rope and the rear hydraulic jacking machine. The spigot end of the second long glass fiber reinforced PE composite pipe section is inserted into the socket end of the first long glass fiber reinforced PE composite pipe section and the teeth of the spigot end are inserted and engaged with the teeth of the socket end to form a self-locking function under the action of the hydraulic jacking machine at the rear end. At the same time, the rubber sealing ring at the root of the spigot end supports the socket port to form a flexible seal. Under the joint action of the front traction machine and traction rope and the rear hydraulic jacking machine, the second long glass fiber reinforced PE composite pipe section is gradually inserted, and the length is continuously extended by analogy until completion.

[0105] In summary, embodiments 1-3 of the present invention provide a long glass fiber composite tube and its production equipment and preparation method, wherein the plastic inner layer and the plastic outer layer are provided with a serrated wall structure, thereby promoting a better overall formation of the long glass fiber composite tube and improving the impact strength and the internal and external pressure resistance. During production, the tube is cooled and shaped by extrusion in the mold, so that it can meet the requirements of manufacturing large-diameter and large-walled pipes, and overcome the problem of uneven wall thickness of the pipe caused by the sag of the large-diameter and large-walled melt.

[0106] The above contents are only specific implementation methods of the present application, and the protection scope of the present application is not limited thereto. Those skilled in the art may make changes or substitutions within the technical scope disclosed in the present application, and these changes or substitutions shall be within the protection scope of the present application.

[0107] Those skilled in the art will appreciate that although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features from different embodiments is meant to be within the scope of the present invention and to form different embodiments.

[0108] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A long fiber composite tube, characterized in that: The invention comprises a plastic inner layer (1), a long fiber composite layer (2) and a plastic outer layer (3) which are sequentially connected from the inside to the outside, wherein the joining surface between the plastic inner layer (1) and the long fiber composite layer (2) is a tooth-shaped structure, and the joining surface between the plastic outer layer (3) and the long fiber composite layer (2) is a tooth-shaped structure. The long fiber composite layer is made of a composite material with a glass fiber length of 2-20 mm, a glass fiber content of 10%-70%, and a plastic content of 30%-90%. One end of the long fiber composite tube is provided with a pipe interface for connecting at least two long fiber composite tubes to each other.

2. The long fiber composite tube according to claim 1, characterized in that: The long fiber composite layer (2) is welded to the plastic inner layer (1) and the plastic outer layer (3) respectively.

3. The long fiber composite tube according to claim 1, characterized in that: The pipeline interface is provided with a sleeve pipe fitting (4) which is socket-welded to the ends of a plurality of long fiber composite pipes, and the sleeve pipe fitting (4) is provided with a plurality of socket openings; the sleeve pipe fitting (4) is made of a composite material with a glass fiber length of 2-20 mm, a glass fiber content of 10%-70%, and a plastic content of 30%-90%.

4. The long fiber composite tube according to claim 1, characterized in that: The pipeline interface is provided with a pipe end butt-welding interface (5), and a continuous glass fiber tape sleeve (51) is welded to the outer wall of the pipe end butt-welding interface (5), and the continuous glass fiber tape sleeve (51) is made of bidirectional continuous glass fiber tapes wound and fused in multiple layers.

5. The long fiber composite tube according to claim 1, characterized in that: The pipeline interface is provided with a meshing self-locking opening (6), and a rubber sealing ring (61) is provided on one side of the meshing self-locking opening.

6. The long fiber composite tube according to claim 1, characterized in that: The pipeline interface is provided with a beveled port butt-welding interface (7).

7. An outer wall sizing production device for a long fiber composite tube according to any one of claims 1 to 6, characterized in that: include: At least two extruders arranged in parallel are connected to a cold ejection multi-layer co-extrusion circular composite mold, wherein the multi-layer co-extrusion cold ejection composite mold is provided with a cooling constant temperature oil tank, and the cooling constant temperature oil tank is connected to the core mold of the inner plastic layer and the outer mold of the outer plastic layer through a back and forth pipeline; A spray vacuum box is provided at the output end of the multi-layer co-extrusion cold ejection composite mold, and is used to further cool the produced long fiber composite tube; A traction machine, arranged at the output end of the spray vacuum box, for traction of the produced long fiber composite tube; A cutting machine, arranged at the output end of the tractor, for cutting the produced long fiber composite tube; The support frame is arranged at the output end of the cutting machine and is used to support the cut long fiber composite tube.

8. A method for preparing the outer wall sizing of a long fiber composite tube according to any one of claims 1 to 6, characterized in that: include: Placing the plastic granules in the inner and outer layer extruders and the long glass fiber granules in the core layer extruder; The temperature of each section of the inner and outer layer extruders and the core layer extruder is controlled at 180-250 degrees Celsius and the extrusion melt pressure is controlled at 100-150 MPa, and the uniformly extruded plastic melt and long glass fiber melt are respectively placed in the co-extrusion mold cavity; A long fiber composite tube composed of a plastic inner layer, a long fiber composite layer and a plastic outer layer is produced by a multi-layer co-extrusion cold ejection composite mold; The outer mold and inner mold of the multi-layer co-extrusion composite mold are cooled and controlled to 60-110 degrees Celsius by cooling oil, and the inner and outer plastic walls are cooled and shaped under pressure in the mold cavity, generating a composite melt with smooth inner and outer tube walls coated with long glass fibers and ejected out of the cavity by strong pressure; The composite melt with the inner and outer tube walls of the ejection cavity coated with long glass fibers is pulled into a cooling box for overall cooling to room temperature to form a long glass fiber composite tube, which is then cut according to a set length.

9. An inner wall sizing production device for a long fiber composite tube as claimed in any one of claims 1 to 6, characterized in that: include: A crimping machine, the crimping machine comprising a driving machine, an inner mold roller and a bracket, the inner mold roller being rotated at a certain angle; A multi-layer co-extrusion flat-mouth die is arranged above the inner die roller side and is inclined at an angle to the cross section of the production line axis; Extruders, at least two of which are mounted on the bracket and connected to the multi-layer co-extrusion flat-mouth die; The pressing rollers are arranged on the outside of the inner mold roller and parallel to the tube axis, the pressing rollers on the inner plastic layer are arranged on the inside of the inner mold roller and parallel to the tube axis, and the pressing rollers on the long glass fiber composite layer are arranged on the outside of the inner mold roller and perpendicular to the tube wall section; A spray cooling water ring is arranged at the output end of the inner mold roller and is used to cool and shape the three-layer composite pipe body to generate a long fiber composite pipe; A cutting machine, arranged at the output end of the spray cooling water ring, for cutting the long fiber composite tube after production; The tube collecting platform is arranged at the output end of the cutting machine and is used for collecting the long fiber composite tube after production.

10. A method for preparing the inner wall sizing of a long fiber composite tube as claimed in any one of claims 1 to 6, characterized in that: include: Placing the plastic granules in the inner and outer layer extruders and the long glass fiber granules in the core layer extruder; The temperature of each section of the inner and outer layer extruders and the core layer extruder is controlled at 180-250 degrees Celsius and the extrusion melt pressure is controlled at 100-150 MPa, and the uniformly extruded plastic melt and long glass fiber melt are respectively placed in the co-extrusion mold cavity to form a three-layer toothed laminated composite melt; The three-layer composite melt with toothed layers is stacked sideways at a certain inclination angle to form a tube wall thickness, thereby generating a three-layer long glass fiber composite tube melt; The melt of the three-layer long glass fiber composite tube is pressed to form a three-layer tube wall, and the three-layer composite tube body is formed by demoulding according to the rotation angle of the inner mold roller; The three-layer composite pipe body is cooled and shaped to generate a long fiber composite pipe, and the long glass fiber composite pipe is cut according to a set length.

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