Continuous fiber reinforced PE pipe double-layer electric hot melting connection process

Abstract

The invention discloses a continuous fiber reinforced PE pipe double-layer electric hot melting connection technology. The technology comprises the steps that a pipeline connector is formed through injection molding; the polyethylene outer layer and the middle fiber reinforced layer at the connecting end of the continuous fiber reinforced PE pipe are cut off, so that the polyethylene inner layer at the connecting end of the continuous fiber reinforced PE pipe is exposed, and a socket head is formed; and the connecting ends of the two continuous fiber reinforced PE pipes are inserted from the two ends of the pipeline joint correspondingly, the polyethylene outer layers of the continuous fiber reinforced PE pipes are welded to the cavity wall of the socket cavity in the circumferential direction, and the outer wall of the socket head is welded to the side wall of the annular boss in the circumferential direction. The first welding surface is formed between the polyethylene outer layer and the cavity wall of the socket cavity, the second welding surface is formed between the outer surface of the socket head and the inner wall of the annular boss, and under the sealing effect of the second welding surface, fluid in a pipeline cannot enter the space between layers from the end face of the continuous fiber reinforced PE pipe, so that the continuous fiber reinforced PE pipe is prevented from entering the space between the layers. And the sealing effect of the end part of the pipe body is improved.

Description

Technical Field

[0001] The invention relates to the technical field of pipeline connection, and specifically discloses a double-layer electric hot-melt connection process for a continuous fiber reinforced PE pipe. Background Art

[0002] Continuous fiber reinforced PE pipes are usually connected by pipe joints with external sockets or internal sockets. Figure 1 As shown, two continuous fiber reinforced PE pipes are respectively inserted into the pipe joint from both ends of the pipe joint, and the outer PE layer of the continuous fiber reinforced PE pipe is welded to the inner wall of the pipe joint by heat welding to achieve the connection between the two continuous fiber reinforced PE pipes. Since the continuous fiber reinforced PE pipe is usually composed of an inner PE layer, an intermediate fiber reinforced layer and an outer PE layer, and the layers are adhered to each other by PE, the above connection method is used, and the fluid in the pipeline is easy to penetrate into the inner wall of the continuous fiber reinforced PE pipe from the end surface layers of the pipe wall, resulting in the shedding of the pipe wall layers, which seriously affects the service life of the continuous fiber reinforced PE pipe. In addition, since the inner socket connection method only welds the outer PE layer to the inner wall of the pipe joint, when the continuous fiber reinforced PE pipe is subjected to a large axial tension, the outer PE layer and the intermediate fiber reinforced layer are also easy to loosen.

[0003] In order to solve the problem of water seepage on the end face of the pipe wall, some technologies attempt to set a sealant layer on the end face of the pipe wall. However, due to the small cross-section of the end face of the pipe wall, the sealant layer is easy to fall off under the scouring of the fluid in the pipe, and cannot solve the above problem. If an external socket connection method is adopted, although it can solve the problem of water seepage on the end face of the pipe wall, it will affect the diameter of the pipeline, and when subjected to a large axial tension, the inner layer of PE and the middle fiber reinforced layer are also easy to loosen. In order to solve the above problem, the present application provides a double-layer electric hot melt connection process for continuous fiber reinforced PE pipes. Summary of the invention

[0004] The purpose of the present invention is to solve the above problems and provide a double-layer electric hot-melt connection process for continuous fiber reinforced PE pipes, which can prevent the fluid in the pipe from penetrating into the pipe wall from the end face of the pipe wall and enable the connected pipe to withstand greater axial tension.

[0005] The purpose of the present invention is achieved by the following technical solution: A continuous fiber reinforced PE pipe double-layer electric hot melt connection process, comprising the following steps:

[0006] Step 1: injection molding the pipe joint to form an annular boss on the inner wall of the pipe joint in a circumferential direction, wherein the annular boss divides the pipe joint into two socket cavities along the axial direction; and circumferentially burying heating wires on the side walls of the two socket cavities and the side walls of the annular boss;

[0007] Step 2: Take the continuous fiber reinforced PE pipe, cut off the polyethylene outer layer and the middle fiber reinforced layer on the connecting end of the continuous fiber reinforced PE pipe, so that the polyethylene inner layer on the connecting end of the continuous fiber reinforced PE pipe is exposed to form a socket plug;

[0008] Step 3: Insert the connecting ends of the two continuous fiber reinforced PE pipes from both ends of the pipe joint respectively, and weld the polyethylene outer layer of the continuous fiber reinforced PE pipe to the cavity wall of the socket cavity circumferentially to form a first welding surface; weld the outer wall of the socket plug to the side wall of the annular boss circumferentially to form a second welding surface.

[0009] Furthermore, before welding, there is a gap of 0.5-1 mm between the inner wall of the socket cavity and the outer surface of the continuous fiber reinforced PE pipe, and there is also a gap of 0.5-1 mm between the inner wall of the annular boss and the outer surface of the socket.

[0010] As an embodiment, the removal of the polyethylene outer layer and the intermediate fiber reinforced layer on the connection end of the continuous fiber reinforced PE pipe in step B includes the following steps:

[0011] Step 2.1: using a radial cutter to radially cut the continuous fiber reinforced PE pipe from the outside to the inside at a set length position of the continuous fiber reinforced PE pipe connection end to form a radial cut; wherein the radial cutting depth is 0.3-0.6 mm into the polyethylene inner layer;

[0012] Step 2.2: Using an axial cutter, perform multiple axial cuts in the circumferential direction from the end of the continuous fiber reinforced PE pipe connection end to the radial cut, so as to cut the continuous fiber reinforced PE pipe connection end into multiple pipe wall units; wherein the depth of the axial cut is the same as the depth of the radial circumferential cut;

[0013] Step 2.3: Take out the pipe wall unit formed by cutting from the continuous fiber reinforced PE pipe, so that the polyethylene inner layer on the connecting end of the continuous fiber reinforced PE pipe is exposed to form a socket plug.

[0014] After step 2.3, the method further includes: grinding the outer surface of the socket.

[0015] As an embodiment, the axial cutter in step 2.2 includes:

[0016] Knife holder;

[0017] Two blades are respectively installed at the two ends of the blade holder; the installation angles of the two blades are such that the blades are perpendicular to the surface of the continuous fiber reinforced PE pipe during cutting;

[0018] Two motors are respectively mounted on the blade holder, and the rotating shafts of the motors are respectively connected to the two blades to drive the two blades to rotate;

[0019] Two supporting rods are connected to the knife seat and are respectively located behind the two blades;

[0020] The scraper is connected between the two support rods; the scraper is in an arc shape, the blade and the lower ends of the two blades are located on an arc with the same radius, and the front end of the blade and the front ends of the two blades are located on the same vertical plane.

[0021] As an embodiment, the method of using an axial cutter in step 2.2 to perform multiple axial cutting in the circumferential direction from the end of the continuous fiber reinforced PE pipe connection end to the radial slit is as follows:

[0022] The axial cutter is moved to the end of the continuous fiber reinforced PE pipe connection end, and the lower ends of the two blades are matched with the depth of the radial slit. The axial cutter is controlled to move axially along the continuous fiber reinforced PE pipe, and the blade is moved axially to the radial slit. The blade cuts an axial slit on the surface of the continuous fiber reinforced PE pipe, and the scraper separates the part of the pipe wall between the two blades from the continuous fiber reinforced PE pipe to form a pipe wall unit.

[0023] The axial cutter is controlled to return to the initial position, the continuous fiber reinforced PE pipe is controlled to rotate an angle α, and the axial cutter is controlled to move axially along the continuous fiber reinforced PE pipe again to cut out another pipe wall unit, and the above steps are repeated to complete the circumferential cutting of the continuous fiber reinforced PE pipe; the degree of the angle α is the same as the angle between the two blades.

[0024] As an embodiment, the scraper is provided with a support portion, and the thickness of the support portion gradually increases from one end close to the blade to the other end.

[0025] As an embodiment, step 1 also includes inserting an electrode at each end of the pipe joint, and the two electrodes are respectively connected to the two ends of the heating wire.

[0026] As an embodiment, the annular boss is located in the middle of the pipe joint.

[0027] As an embodiment, the heating wire is spirally embedded in the cavity wall of the socket cavity and the inner wall of the annular boss, or the heating wire is axially embedded in the cavity wall of the socket cavity and the inner wall of the annular boss.

[0028] Compared with the prior art, this application has the following beneficial effects:

[0029] (1) A first welding surface is formed between the polyethylene outer layer of the continuous fiber reinforced PE pipe of the present invention and the cavity wall of the socket cavity, and a second welding surface is formed between the outer surface of the socket formed by the polyethylene inner layer and the inner wall of the annular boss. Under the sealing effect of the second welding surface, the fluid in the pipeline cannot enter between the layers from the end face of the continuous fiber reinforced PE pipe. Compared with the traditional method of using end face sealing glue, the sealing area of ​​the second welding surface can be set larger, thereby improving the sealing effect of the end of the pipe body.

[0030] (2) The present invention welds the polyethylene outer layer and the polyethylene inner layer of the continuous fiber reinforced PE pipe to the pipe joint respectively. When the pipe is subjected to axial tension, the polyethylene outer layer and the polyethylene inner layer can share the axial tension, thereby preventing the axial tension from being concentrated on the polyethylene outer layer and causing the polyethylene outer layer and the middle fiber reinforced layer to loosen, thereby improving the axial tensile performance of the pipe after connection.

[0031] (3) In the present invention, before welding, there is a certain gap between the inner wall of the socket cavity and the outer surface of the continuous fiber reinforced PE pipe, and there is also a certain gap between the inner wall of the annular boss and the outer surface of the socket. This can avoid the problem of less polyethylene material available for welding due to the softened polyethylene material being squeezed out from the end of the pipe joint due to expansion during welding, thereby making the connection between the continuous fiber reinforced PE pipe and the pipe joint more secure.

[0032] Some additional features of the present application may be explained in the following description. Some additional features of the present application will be apparent to those skilled in the art by inspection of the following description and corresponding drawings or understanding of the production or operation of the embodiments. The features disclosed in the present application may be realized and achieved by practice or use of various methods, means and combinations of the specific embodiments described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The exemplary embodiments of the present application and their descriptions are used to explain the present application and do not constitute a limitation of the present application. In each figure, the same reference numeral represents the same component.

[0034] Figure 1 Schematic diagram of the traditional connection method between continuous fiber reinforced PE pipes.

[0035] Figure 2 A cross-sectional view of a pipe joint used in the method of the present invention.

[0036] Figure 3 It is a cross-sectional view of a continuous fiber reinforced PE pipe cut by the method of the present invention.

[0037] Figure 4This is a schematic diagram of continuous fiber reinforced PE pipes connected using the method of the present invention.

[0038] Figure 5 The schematic diagram of the structure of the axial cutter used in the method of the present invention.

[0039] Figure 6 A schematic cross-sectional view of a scraper used in the method of the present invention.

[0040] Figure 7 This is a schematic diagram of the state of the axial cutter during cutting.

[0041] The figure marks in the above drawings are: 1-pipe joint, 2-annular boss, 3-heating wire, 4-socket cavity, 5-electrode, 6-polyethylene inner layer, 7-intermediate fiber reinforced layer, 8-polyethylene outer layer, 9-socket plug, 10-continuous fiber reinforced PE pipe, 12-knife seat, 13-blade, 14-motor, 16-support rod, 17-scraper, 18-blade, 19-opening part. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0043] It should be noted that if the description and claims of the present application and the above-mentioned drawings relate to the terms "first", "second", etc., they are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, if the terms "including" and "having" and any of their variations are involved, it is intended to cover non-exclusive inclusions, for example, the process, method, system, product or equipment that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0044] In this application, if the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside", "outside", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. are involved, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0045] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0046] In addition, in this application, the terms "installed", "set", "provided with", "connected", "connected", "socketed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0047] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0048] Example 1

[0049] This embodiment discloses a double-layer electric hot-melt connection process for continuous fiber reinforced PE pipe, which includes the following steps:

[0050] Step 1: injection molding a pipe joint 1, wherein an annular boss 2 is formed on the inner wall of the pipe joint 1. Specifically, the pipe joint 1 is a pipe fitting, wherein the annular boss 2 is annularly protruding toward the central axis of the pipe joint 1, so that the annular boss 2 divides the interior of the pipe joint 1 into two socket cavities 4 along the axial direction, and the two socket cavities 4 are connected via the internal channel of the annular boss 2, such as Figure 2 In the specific configuration, the pipe joint 1 and the annular boss 2 are integrally injection molded, and the annular boss 2 is located in the middle of the pipe joint 1, so that the lengths of the two socket cavities 4 are the same. In this embodiment, the entire pipe joint 1 is made of polyethylene material.

[0051] After the pipe joint 1 is injection molded, a wire laying machine is used to embed the heating wire 3 in the cavity wall of the socket cavity 4 and the inner wall of the annular boss 2. In the specific setting, the heating wire 3 can be spirally embedded in the cavity wall of the socket cavity 4 and the inner wall of the annular boss 2. Alternatively, the heating wire 3 can also be axially embedded in the cavity wall of the socket cavity 4 and the inner wall of the annular boss 2, that is, the heating wire 3 extends axially along the socket cavity 4 and the annular boss 2, and is circumferentially distributed in the cavity wall of the socket cavity 4 and the inner wall of the annular boss 2 in a folded manner. In this embodiment, the cavity wall of the socket cavity 4 and the inner wall of the annular boss 2 are spirally embedded circumferentially.

[0052] After the rear heating wire is arranged on the inner wall of the pipe joint 1, an electrode 5 is inserted at both ends of the pipe joint 1, and the two electrodes 5 are connected to the two ends of the heating wire 3 respectively. Figure 1 shown.

[0053] Step 2: Take the continuous fiber reinforced PE tube 10, cut off the polyethylene outer layer 8 and the middle fiber reinforced layer 7 on the connecting end of the continuous fiber reinforced PE tube 10, so that the polyethylene inner layer 6 on the connecting end of the continuous fiber reinforced PE tube 10 is exposed, and a socket 9 is formed. Figure 3 shown.

[0054] The continuous fiber reinforced PE pipe 10 includes a polyethylene inner layer 6, a fiber reinforced layer 7 coated on the outside of the polyethylene inner layer 6, and a polyethylene outer layer 8 coated on the outside of the fiber reinforced layer 7. The fiber reinforced layer 7 can be a basalt fiber layer or a glass fiber layer. In specific implementation, the polyethylene outer layer 8 and the intermediate fiber reinforced layer 7 on the connecting end of the continuous fiber reinforced PE pipe 10 can be cut from the outside to the inside by lathe cutting. During the cutting process, the polyethylene inner layer 6 can be partially cut off with a cutting thickness of 0.3-0.6mm to ensure that the fiber reinforced layer 7 on the connecting end is completely removed. In this embodiment, the polyethylene inner layer 6 with a thickness of 0.5mm is cut off.

[0055] Step 3: After cutting the socket 9 from the continuous fiber reinforced PE tube 10, the connecting ends of the two continuous fiber reinforced PE tubes 10 are respectively inserted from both ends of the pipe joint 1, that is, the ends of the two continuous fiber reinforced PE tubes 10 with the socket 9 are respectively inserted into the pipe joint 1 from both ends of the pipe joint 1, so that the socket 9 of the continuous fiber reinforced PE tube 10 is inserted into the annular boss 2, the end step of the socket 9 is tightly abutted against the side step of the annular boss 2, and a part of the pipe section of the continuous fiber reinforced PE tube 10 that has not been cut is inserted into the socket cavity 4.

[0056] Next, an external power supply device is used to energize the heating wire 3 through the two electrodes 5 of the pipe joint 1, so that the heating wire 3 is heated, and the cavity wall of the socket cavity 4, the polyethylene outer layer 8 of the pipe section located in the socket cavity 4, the inner wall of the annular boss 2, and the outer wall of the socket plug 9 are heated and softened, so that the polyethylene outer layer 8 of the pipe section located in the socket cavity 4 is circumferentially welded to the cavity wall of the socket cavity 4 to form a first welded surface, and the outer wall of the socket plug 9 is circumferentially welded to the side wall of the annular boss 2 to form a second welded surface, as shown in FIG. Figure 4 shown.

[0057] In specific implementation, the length of the annular boss 2 is the same as the total length of the socket plugs 9 on the two continuous fiber reinforced PE pipes 10 to be connected. Therefore, when the two continuous fiber reinforced PE pipes 10 are respectively inserted into the pipe joint 1 and the end step of the socket plug 9 is tightly abutted against the side step of the annular boss 2, the ends of the two socket plugs 9 are just butted, which can reduce the scouring of the second welding surface by the fluid in the pipe and make the adhesion between the two continuous fiber reinforced PE pipes 10 and the pipe joint 1 more uniform.

[0058] In this embodiment, the polyethylene outer layers 8 of the two continuous fiber reinforced PE pipes to be connected are welded to the cavity wall of the socket cavity 4 to form a first welding surface, and the outer surface of the socket formed by the polyethylene inner layer is welded to the inner wall of the annular boss 2 to form a second welding surface. Since the sealing area of ​​the second welding surface is larger, under the sealing effect of the second welding surface, the fluid in the pipeline is not easy to penetrate through the second welding surface, and enter between the polyethylene inner layer 6 and the fiber reinforced layer 7 and between the fiber reinforced layer 7 and the polyethylene outer layer 8 from the end face of the continuous fiber reinforced PE pipe. Compared with the traditional method of using end face sealing glue, it can greatly improve the sealing effect of the end of the pipe body.

[0059] In addition, in this embodiment, the polyethylene outer layer 8 and the polyethylene inner layer 6 of the continuous fiber reinforced PE pipe 10 are respectively welded to the pipe joint 1. When the pipe is subjected to axial tension, the polyethylene outer layer 8 and the polyethylene inner layer 6 can share the axial tension, thereby preventing the axial tension from being concentrated entirely on the polyethylene outer layer 8 or the polyethylene inner layer 6, thereby causing the polyethylene outer layer 8 and the intermediate fiber reinforced layer 7 to loosen, or the polyethylene inner layer 6 and the intermediate fiber reinforced layer 7 to loosen, thereby improving the axial tensile resistance of the continuous fiber reinforced PE pipe 10 after connection.

[0060] In addition, in a specific implementation, the size of the pipe joint 1 can satisfy that after the continuous fiber reinforced PE pipe 10 is inserted into the pipe joint 1 and before welding, there is a gap of 0.5-1 mm between the inner wall of the socket cavity 4 and the outer surface of the continuous fiber reinforced PE pipe 10, and between the inner wall of the annular boss 2 and the outer surface of the socket plug 9. In this embodiment, the gap width is set to 1 mm.

[0061] Since the polyethylene material will expand after being softened, if the continuous fiber reinforced PE pipe 10 is inserted into the pipe joint 1, the outer surface of the continuous fiber reinforced PE pipe 10 fits with the inner wall of the socket cavity 4, and the inner wall of the annular boss 2 fits with the outer surface of the socket 9. The softened and expanded polyethylene material is squeezed out from the end of the pipe joint 1 due to the lack of accommodation space, resulting in less polyethylene material used for welding the continuous fiber reinforced PE pipe 10 and the pipe joint 1, affecting the welding firmness between the continuous fiber reinforced PE pipe 10 and the pipe joint 1. Through the above design, the present embodiment prevents the softened and expanded polyethylene material from being squeezed out from the end of the pipe joint 1 in large quantities, ensuring the amount of polyethylene material used for welding the continuous fiber reinforced PE pipe 10 and the pipe joint 1, and improving the welding firmness between the continuous fiber reinforced PE pipe 10 and the pipe joint 1.

[0062] Example 2

[0063] This embodiment is basically the same as the embodiment 1, except that the cutting method of the continuous fiber reinforced PE pipe 10 is different, that is, this embodiment adopts another method to cut the socket 9 on the continuous fiber reinforced PE pipe 10.

[0064] Since the intermediate fiber reinforced layer 7 is formed by winding the reinforcing fiber bundle on the polyethylene inner layer 6, cutting from the outside to the inside using a lathe may cause fiber bundle pulling problems and affect the cutting effect. Therefore, this embodiment provides a new cutting method and an axial cutter applied to the method.

[0065] like Figure 5 As shown, the axial cutter includes: a cutter seat 12, two blades 13, two motors 14, two support rods 16 and a scraper 17. The axial cutter is installed on the cutting machine through its cutter seat 12, and the two blades 13 are respectively installed at both ends of the cutter seat 12. When installing, the installation angle of the two blades 13 must meet the requirement that the blades 13 are perpendicular to the surface of the continuous fiber reinforced PE pipe 10 during axial cutting, as shown in FIG. Figure 7 As shown. Two motors 14 are respectively installed on the knife seat 12, and their rotating shafts are respectively connected to the two blades 13, and the two motors 14 are respectively used to drive the two blades 13 to rotate. Two support rods 16 are connected to the knife seat 12 and are respectively located behind the two blades 13, and the scraper 17 is connected between the two support rods 16. Since the two support rods 16 are respectively located behind the two blades 13, when the two blades 13 cut the continuous fiber reinforced PE pipe 10 forward, the two support rods 16 can be respectively stuck in the two axial cutting grooves cut out, so as to avoid the axial cutter being unable to move forward due to the two support rods 16 abutting against the pipe wall. The scraper 17 is in an arc shape so that the scraper 17 can match the shape of the continuous fiber reinforced PE pipe 10.

[0066] In addition, the blade 18 of the scraper 17 and the lower ends of the two blades 13 are located on an arc of the same radius, as shown in FIG. Figure 7 As shown, when the axial cutter cuts the continuous fiber reinforced PE tube 10 forward, the two blades 13 cut two axial cutting grooves, and the scraper 17 cuts the tube wall area between the two axial cutting grooves from the end of the continuous fiber reinforced PE tube 10, so that the area is separated from the continuous fiber reinforced PE tube 10 to form a tube wall unit. The blade 18 of the scraper 17 and the lower ends of the two blades 13 are located on the same radius arc to ensure that the depth of the two axial cutting grooves is the same as the cutting depth of the scraper 17. In addition, the front end of the blade 18 of the scraper 17 and the front ends of the two blades 13 are located on the same vertical plane, so that the length of the axial cutting of the blade 13 is ensured to be the same as the length of the axial cutting of the scraper 17.

[0067] Since the blade 13 is circular, the depth of the groove cut by the front end of the blade 13 is shallow, resulting in the front end of the pipe wall unit still being slightly adhered to the continuous fiber reinforced PE pipe 10. However, only a slight force is needed to tear off the adhered PE material and remove the pipe wall unit.

[0068] In the specific implementation, the two ends of the scraper 17 need to be close to the two blades 13 respectively, but cannot contact the two blades 13. If they contact the two blades 13, the normal rotation of the blades 13 will be affected. If the two ends of the scraper 17 are too far away from the two blades 13, there will be thicker PE material between the two axial cutting grooves and the cutting grooves cut by the scraper 17, making it difficult to remove the tube wall unit. Only when the two ends of the scraper 17 need to be close to the two blades 13 respectively, such as 0.2mm, it will not affect the normal rotation of the blades 13, and the remaining PE material will be thinner and easier to be torn off, and the tube wall unit will be easy to remove.

[0069] Further, such as Figure 6 As shown, the scraper 17 is provided with a spreading portion 19, which is located behind the blade 18, and the thickness of the spreading portion 19 gradually increases from one end close to the blade 18 to the other end. Since the spreading portion 19 gradually thickens from front to back, when the axial cutter cuts the continuous fiber reinforced PE pipe 10 forward, the pipe wall unit is gradually pushed up by the spreading portion 19, thereby tearing off the residual PE material between the two axial cutting grooves and the cutting groove cut by the scraper 17.

[0070] In this embodiment, the method of using the above-mentioned axial cutter to cut out the socket 9 on the continuous fiber reinforced PE pipe 10 is as follows:

[0071] Step 2.1: Fix the continuous fiber reinforced PE tube 10 on a cutting machine, which is provided with a radial cutter and an axial cutter. The cutting machine controls the movement of the radial cutter, and uses the radial cutter to radially cut the continuous fiber reinforced PE tube 10 from the outside to the inside at a set length position at the connection end of the continuous fiber reinforced PE tube 10. The set length position is the length of the socket 9. During cutting, the cutting machine drives the continuous fiber reinforced PE tube 10 to rotate, thereby cutting a radial slit at the connection end of the continuous fiber reinforced PE tube 10. Among them, the radial cutting depth is 0.5mm into the inner layer of polyethylene.

[0072] Step 2.2: Use an axial cutter to perform multiple axial cuts from the end of the continuous fiber reinforced PE pipe 10 connection end to the radial cut to cut the continuous fiber reinforced PE pipe 10 connection end into multiple pipe wall units; wherein the depth of the axial cut is the same as the depth of the radial cut. The specific steps are as follows:

[0073] The axial cutter is controlled to move to the end of the connection end of the continuous fiber reinforced PE pipe 10, and the lower ends of the two blades 13 are matched with the depth of the radial cut to ensure that the depth of the axial cutting is the same as the depth of the radial annular cutting.

[0074] The axial cutter is controlled to move axially along the continuous fiber reinforced PE tube 10, so that the blade 13 cuts axially to the position of the radial slit, and at this time, the two blades 13 cut axial slits on the surface of the continuous fiber reinforced PE tube 10. At the same time, as the axial cutter moves forward, the scraper 17 cuts the part of the tube wall between the two axial slits from the continuous fiber reinforced PE tube 10, and under the lifting action of the expansion part 19, this part of the tube wall is lifted relative to the continuous fiber reinforced PE tube 10 to form a tube wall unit; at this time, a small part of the PE material at the front end of the tube wall unit is still connected to the tube body.

[0075] Next, the cutting machine controls the axial cutter to return to the initial position and controls the continuous fiber reinforced PE tube 10 to rotate by an angle α, the angle α being the same as the angle between the two blades 13. Then the cutting machine controls the axial cutter to move along the axial direction of the continuous fiber reinforced PE tube 10 again to cut out another tube wall unit. Repeat the above steps to complete the circumferential cutting of the continuous fiber reinforced PE tube 10. Figure 7 As shown, after the first axial cutting, if the continuous fiber reinforced PE tube 10 is rotated counterclockwise by an angle α, when the subsequent cutting is performed, the blade 13 on the left side does not play a cutting role because the previous cutting has been performed, and only the blade 13 on the right side cuts the continuous fiber reinforced PE tube 10, while the scraper 17 plays a cutting role every time. When the last cutting is performed, the width of the remaining uncut tube wall may be less than the spacing between the two blades 13, but this does not affect the normal cutting of the scraper 17.

[0076] Step 2.3: After the continuous fiber reinforced PE pipe 10 is circumferentially cut, the pipe wall unit formed by the cutting is removed from the continuous fiber reinforced PE pipe 10 manually or by external equipment, so that the polyethylene inner layer 6 on the connecting end of the continuous fiber reinforced PE pipe 10 is exposed to form a socket 9.

[0077] Step 2.4, fix the cut continuous fiber reinforced PE pipe 10 on a grinding device, and grind the outer surface of the socket 9.

[0078] In this embodiment, the rotating blade 13 cuts an axial slit, which will not pull the fiber bundles on the intermediate fiber reinforced layer 7, and the scraper 17 directly starts axial cutting from the polyethylene inner layer 6, which avoids the hard intermediate fiber reinforced layer 7 and will not pull the fiber bundles on the intermediate fiber reinforced layer 7, thereby improving the cutting effect.

[0079] It should be noted that all features disclosed in this specification, or steps in all methods or processes disclosed, except for mutually exclusive features and / or steps, can be combined in any manner.

[0080] In addition, the above specific embodiments are exemplary, and those skilled in the art can come up with various solutions inspired by the disclosure of the present invention, and these solutions also belong to the disclosure scope of the present invention and fall within the protection scope of the present invention. Those skilled in the art should understand that the present invention description and its drawings are illustrative and do not constitute a limitation of the claims. The protection scope of the present invention is defined by the claims and their equivalents.

Claims

1. A double-layer electric hot-melt connection process for continuous fiber reinforced PE pipe, characterized in that: The following steps are involved: Step 1: injection molding a pipe joint (1); an annular boss (2) is formed circumferentially on the inner wall of the pipe joint (1), and the annular boss (2) divides the pipe joint (1) into two socket cavities (4) along the axial direction; a heating wire (3) is buried circumferentially on the side walls of the two socket cavities (4) and the side walls of the annular boss (2); Step 2: Take the continuous fiber reinforced PE tube (10), cut off the polyethylene outer layer (8) and the intermediate fiber reinforced layer (7) on the connecting end of the continuous fiber reinforced PE tube (10), expose the polyethylene inner layer (6) on the connecting end of the continuous fiber reinforced PE tube (10), and form a socket (9); Step 3: insert the connection ends of the two continuous fiber reinforced PE pipes (10) from both ends of the pipe joint (1), and weld the polyethylene outer layer (8) of the continuous fiber reinforced PE pipe (10) to the cavity wall of the socket cavity (4) in the circumferential direction to form a first welding surface; weld the outer wall of the socket plug (9) to the side wall of the annular boss (2) in the circumferential direction to form a second welding surface.

2. The double-layer electric hot-melt connection process of continuous fiber reinforced PE pipe according to claim 1 is characterized in that: Before welding, there is a gap of 0.5-1 mm between the inner wall of the socket cavity (4) and the outer surface of the continuous fiber reinforced PE pipe (10), and there is also a gap of 0.5-1 mm between the inner wall of the annular boss (2) and the outer surface of the socket plug (9).

3. The double-layer electric hot-melt connection process of continuous fiber reinforced PE pipe according to claim 1 is characterized in that: In step B, the polyethylene outer layer (8) and the intermediate fiber reinforced layer (7) on the connection end of the continuous fiber reinforced PE pipe (10) are cut off, which includes the following steps: Step 2.1: using a radial cutter to radially cut the continuous fiber reinforced PE tube (10) from the outside to the inside at a set length position of the connection end of the continuous fiber reinforced PE tube (10) to form a radial cut; wherein the radial cut depth is 0.3-0.6 mm into the polyethylene inner layer (6); Step 2.2: using an axial cutter to perform multiple axial cuts in the circumferential direction from the end of the continuous fiber reinforced PE pipe (10) connection end to the radial cut, so as to cut the continuous fiber reinforced PE pipe (10) connection end into a plurality of pipe wall units; wherein the depth of the axial cut is the same as the depth of the radial cut; Step 2.3: The pipe wall unit formed by cutting is taken out from the continuous fiber reinforced PE pipe (10), so that the polyethylene inner layer (6) on the connecting end of the continuous fiber reinforced PE pipe (10) is exposed to form a socket (9).

4. The double-layer electric hot-melt connection process of continuous fiber reinforced PE pipe according to claim 3 is characterized in that: After step 2.3, the method further includes: grinding the outer surface of the socket (9).

5. The double-layer electric hot-melt connection process of continuous fiber reinforced PE pipe according to claim 4 is characterized in that: The axial cutters in step 2.2 include: Knife holder(12); Two blades (13) are respectively mounted at two ends of the blade holder (12); the mounting angles of the two blades (13) are such that the blades (13) are perpendicular to the surface of the continuous fiber reinforced PE pipe (10) during cutting; Two motors (14) are respectively mounted on the blade holder (12), and the rotating shafts of the motors (14) are respectively connected to the two blades (13) for driving the two blades (13) to rotate; Two support rods (16) are connected to the blade seat (12) and are respectively located behind the two blades (13); The scraper (17) is connected between the two support rods (16); the scraper (17) is in an arc shape, and the blade (18) thereof and the lower ends of the two blades (13) are located on an arc with the same radius, and the front end of the blade (18) and the front ends of the two blades (13) are located on the same vertical plane.

6. The double-layer electric hot-melt connection process of continuous fiber reinforced PE pipe according to claim 5 is characterized in that: In step 2.2, the method of using an axial cutter to perform multiple axial cutting in the circumferential direction from the end of the connection end of the continuous fiber reinforced PE pipe (10) to the radial slit is as follows: The axial cutter is moved to the end of the connection end of the continuous fiber reinforced PE pipe (10), and the lowermost ends of the two blades (13) are matched with the depth of the radial slit. The axial cutter is controlled to move axially along the continuous fiber reinforced PE pipe (10), so that the blade (13) moves axially to the radial slit. The blade (13) cuts an axial slit on the surface of the continuous fiber reinforced PE pipe (10), and the scraper (17) separates the portion of the pipe wall between the two blades (13) from the continuous fiber reinforced PE pipe (10), thereby forming a pipe wall unit. The axial cutter is controlled to return to the initial position, the continuous fiber reinforced PE tube (10) is controlled to rotate by an angle α, and the axial cutter is controlled to move axially along the continuous fiber reinforced PE tube (10) again to cut out another tube wall unit, and the above steps are repeated to complete the circumferential cutting of the continuous fiber reinforced PE tube (10); the angle α is the same as the angle between the two blades (13).

7. The double-layer electric hot-melt connection process of continuous fiber reinforced PE pipe according to claim 6 is characterized in that: The scraper (17) is provided with an open portion (19), and the thickness of the open portion (19) gradually increases from one end close to the blade (18) to the other end.

8. The double-layer electric hot-melt connection process of continuous fiber reinforced PE pipe according to claim 1 is characterized in that: Step 1 also includes inserting an electrode (5) at each end of the pipe joint (1), and the two electrodes (5) are respectively connected to the two ends of the heating wire (3).

9. The electric heat fusion joint according to claim 1, characterized in that: The annular boss (2) is located in the middle of the pipe joint (1).

10. The electric heat fusion joint according to claim 1, characterized in that: The heating wire (3) is spirally embedded in the cavity wall of the socket cavity (4) and the inner wall of the annular boss (2), or the heating wire (3) is axially embedded in the cavity wall of the socket cavity (4) and the inner wall of the annular boss (2).

Images