CN117759790A - Socket-type multi-layer pipe with end edges and manufacturing method thereof - Google Patents

Abstract

The invention discloses a socket multi-layer pipe with an end face and a side face and a manufacturing method thereof. The manufacturing method comprises the following steps: treating the outer tube, manufacturing the inner tube and the middle layer; the inner tube, the middle layer and the outer tube are sequentially arranged from inside to outside; compacting each layer; and setting a wrapping edge. The corrosion-resistant inner pipe provided by the invention has the advantages that the corrosion of the outer pipe is avoided, the water quality is polluted, the thickness of the inner liner is smaller, the inner pipe and the outer pipe are completely separated by the middle layer, the edge wrapping and the inner sleeve are integrated, the electrochemical corrosion of the inner sleeve and the flushing of the inner sleeve by water flow are prevented, the edge wrapping has no steps, and the water flow resistance of the steps is avoided.

Description

A socket-type multi-layer pipe with edged ends and a manufacturing method thereof

Technical field

The invention belongs to the technical field of pipe processing and manufacturing, and specifically relates to a socket-type multi-layer pipe with end cladding and a manufacturing method thereof.

Background technique

In the existing technology, multi-layer pipes are generally composite pipes, and composite pipes are widely used in liquid transportation pipe network systems. When used, the parts of the pipe that are in contact with the liquid are required to have good anti-corrosion properties to prevent the pipe from being rusted due to long-term contact with liquid and affecting the quality of the transported liquid. Existing composite pipes generally have an outer layer of metal pipe and an inner layer of plastic pipe, that is, the plastic pipe serves as the lining, and the inner layer and the outer layer are compounded through a composite process. The structure of existing composite pipes is generally a socket structure, with one end of the metal pipe being a socket end and the other end being a socket end. The two ends of the composite pipe are respectively provided with lining rings, pressing linings and end faces. The lining rings at both ends are used to press the plastic pipes at the spigot end and the socket end onto the metal pipe and cover the end faces to prevent compounding during use. The end face of the pipe has been eroded for a long time, resulting in delamination. However, the lining ring and the lining are independent. One end of the lining ring presses against the surface of the lining to form a step. Under long-term erosion by liquid, the lining ring has the risk of loosening or even falling off. The transported liquid may penetrate into the composite through the loose lining ring. Pipe end surface, contaminating the quality of the transported liquid. The inner diameter of the pipe at the lining ring is reduced, and the steps formed by the lining ring and the lining cause the fluid resistance in the pipe to increase and the energy consumption to increase. In addition, the thermal expansion coefficient of the plastic pipe lining is very different from that of the metal outer pipe. Due to temperature changes, the inner pipe and the outer pipe will generate a certain amount of mutually separated internal stress, which will cause the lining to delaminate.

Contents of the invention

In view of the above-mentioned problems existing in the prior art, the purpose of the present invention is to provide an end-bordered socket-type multi-layer pipe and a manufacturing method thereof. The inner pipe of corrosion-resistant material is used as the lining, and the outer pipe is circulated with the inside of the pipe. The liquid is completely isolated to prevent the corrosion of the outer pipe from contaminating the water quality and improve the liquid transportation performance. The smaller thickness of the lining improves the water delivery efficiency of the pipeline and reduces operating energy consumption. The middle layer is made of plastic, which completely separates the inner tube and the outer tube, preventing the outer tube from contacting the inner tube and causing electrochemical corrosion of the inner tube. At the same time, it eliminates the uneven glue layer caused by the flow of ordinary liquid glue in the middle layer, and the inner tube. The lining and the outer metal pipe are not bonded but are in direct contact to cause electrochemical corrosion. It also overcomes the problems of ordinary glue that is easy to age and has poor insulation. There are sealing gaskets and corrosion-resistant edging at both ends of the middle layer. The sealing gasket separates the edging from the metal outer pipe to prevent electrochemical corrosion of the edging after contact. It also prevents water from penetrating into the inner wall of the outer pipe and polluting the water quality. The edge wrapping and the inner sleeve are integrally formed or welded together to fix the inner sleeve, prevent the water flow from directly impacting the end of the inner sleeve, and prevent the inner sleeve from being washed away by the erosion of the water flow. The edge-wrapped and non-wrapped steps eliminate the flow resistance caused by the steps, making the pipe more efficient in delivering water and consuming less energy in operation.

In order to achieve the above objects, the technical solutions adopted by the present invention are:

A socket-type multi-layer pipe with end cladding, including an inner pipe, a middle layer and an outer pipe. The middle layer is made of an insulating material, the inner pipe is made of a corrosion-resistant material, and the outer pipe consists of The socket part, the straight tube part and the socket part are connected. One end of the inner tube covers the end surface of the socket part and the other end covers the end surface of the straight tube part. The inner tube, the middle layer and the outer tube are pressed together to form the pipe.

As a further improvement of the above technical solution:

Preferably, the inner tube includes an inner sleeve and two edges, the inner sleeve and the two edges are integrated, and the inner sleeve, the middle layer and the outer tube are connected in sequence from the inside to the outside.

Preferably, the end surface of the socket part is covered by a sealing gasket, the end surface of the straight tube part is covered by another sealing gasket, and the sealing gasket is pressed tightly by the wrapping edge.

More preferably, the sealing gasket at one end of the socket part is pressed tightly by one wrapping edge and the upper end surface of the sealing gasket does not exceed the upper end surface of the wrapping edge after wrapping, and the sealing gasket at one end of the straight pipe part is pressed tightly and sealed by another wrapping edge. The upper end surface of the pad shall not exceed the upper end surface of the wrapped edge.

More preferably, the two ends of the inner tube are flanged to form two wrapping edges at both ends. The inner sleeve covers the inner wall of the straight tube part and the inner wall of the spigot part. The two wrapping edges press the sealing gasket and the straight pipe end face of the spigot part respectively. Gasket for pipe end face.

Preferably, the length of the inner sleeve is less than the sum of the length of the straight pipe part and the length of the socket part, and the inner sleeve is welded to the two edges.

More preferably, the thickness of the hemming is greater than the thickness of the inner sleeve.

Preferably, the hemming includes an integrally connected hemming press and a hemming flange. At one end of the socket, the hemming and flanging presses the sealing gasket on the end face of the socket, and the hemming and flange is located on the inner wall of one end of the socket of the pipe. Go up and press the sealing gasket and/or the middle layer on the inner wall of the socket part. At one end of the socket part, press the sealing gasket on the end face of the straight pipe part with the hemming and flanging. The hemming and crimping edge is located at one end of the straight pipe part of the pipe. The sealing gasket and/or the intermediate layer on the inner wall and the inner wall of the straight pipe portion.

Preferably, the length of the hemming and crimping is not less than 20mm.

Preferably, the material of the middle layer is plastic, and the material of the outer tube is metal.

More preferably, the outer tube is made of ductile iron or carbon steel.

Preferably, the thickness of the middle layer is not less than 0.2mm, and the thickness of the inner sleeve 21 is not less than 0.1mm.

A method for manufacturing end-clad socket-type multi-layer pipes, used to manufacture the multi-layer pipes, including the following steps:

Step S1: Process the inner and outer walls of the outer tube, make the inner tube, and make the middle layer;

Step S2: Arrange the inner tube, middle layer and outer tube in sequence from inside to outside;

Step S3: Press the inner tube and the middle layer tightly onto the outer tube;

Step S4: Set hemming at both ends of the inner pipe so that the hemming covers the end face of one end of the spigot portion and the end face of the straight pipe portion.

Preferably, in step S3, the inner tube is tightly pressed against the inner wall of the outer tube through spin forming or hydraulic forming.

Preferably, in step S1, the inner tube can be made as a whole, and then in step S4, both ends of the inner tube are flanged to form hemming; or in step S1, the inner sleeve and the hemming can be made separately, and then in step S4 , weld the inner sleeve and the edge.

Preferably, when the inner sleeve and the hemming are welded, the welding point is located on the inner wall of the pipe.

The beneficial effects of the present invention are:

(1) The inner pipe made of corrosion-resistant material serves as the lining, which completely isolates the outer pipe from the liquid circulating in the pipe, effectively prevents the outer pipe from rusting, plays a good anti-corrosion role, increases the service life of the pipe, and avoids external corrosion. The corrosion of the pipe pollutes the water quality and improves the liquid transportation performance.

(2) The inner pipe made of corrosion-resistant material is used as the lining. Compared with the plastic pipe lining, it eliminates the inner surface wrinkles and uneven unevenness defects caused by the thermal melting of the lining plastic during compounding, and improves the smoothness of the inner surface of the pipe. The thickness of the lining is small, which improves the water delivery efficiency of the pipeline and reduces the operating energy consumption.

(3) The inner pipe made of corrosion-resistant material is used as the lining. Compared with the plastic pipe lining, the pipe can be used to transport high-temperature liquid media.

(4) The middle layer is made of plastic, which completely separates the inner tube and the outer tube, preventing the outer tube from contacting the inner tube and causing electrochemical corrosion of the inner tube. It also eliminates the uneven glue layer caused by the flow of ordinary liquid glue in the middle layer. , as well as the electrochemical corrosion caused by direct contact between the inner lining and the outer metal pipe without bonding, and also overcomes the problems of ordinary glue that is easy to age and has poor insulation.

(5) There are sealing gaskets and corrosion-resistant edging at both ends of the middle layer. The sealing gasket separates the edging from the metal outer pipe to prevent electrochemical corrosion of the edging after contact, and at the same time prevents water from penetrating into the inner wall of the outer pipe and causing damage to the water quality. pollution. In addition, the hemming is a part of the inner pipe. The hemming and the inner sleeve are integrally formed or welded to fix the inner sleeve, prevent the water flow from directly impacting the end of the inner sleeve, and prevent the inner sleeve from being washed away by the erosion of the water flow. .

(6) In the case of welding of the inner sleeve and the edge covering, since the two can be made independently, the thickness of the edge covering can be selected to be larger than that of the inner sleeve, which improves the stiffness of the edge covering, the sealing effect of the gasket and the fixation of the inner sleeve. Reduce pipe leakage, make the edge less likely to deform, eliminate the need to increase the thickness of the inner sleeve, reduce production costs, and facilitate pipe installation.

(7) Compared with the process of installing lining rings on the inner linings at both ends of the pipe, the hemming and inner pipe of this solution will not form steps, eliminating the flow resistance caused by the steps. The pipe water transport efficiency is higher and the operation performance is higher. Lower consumption.

Description of the drawings

Figure 1 is a schematic structural diagram of the pipe when the sealing gasket according to Embodiment 1 of the present invention does not have a flange.

Figure 2 is a schematic structural diagram of the pipe when the sealing gasket has a flange and a flange according to Embodiment 1 of the present invention.

FIG. 3 is an enlarged schematic diagram of position A in FIG. 2 .

Figure 4 is a schematic structural diagram of the pipe when the sealing gasket in Embodiment 2 of the present invention does not have a flange.

Figure 5 is a schematic structural diagram of the pipe when the sealing gasket in Embodiment 2 of the present invention has a flange and a flange.

FIG. 6 is an enlarged schematic diagram of C in FIG. 5 .

Detailed ways

Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

For the convenience of description, spatially relative terms can be used here, such as "on...", "on...", "on the upper surface of...", "above", etc., to describe what is shown in the figure. The spatial relationship between one device or feature and other devices or features. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a feature in the figure is turned upside down, then one feature described as "above" or "on top of" other features or features would then be oriented "below" or "below" the other features or features. under other devices or structures". Thus, the exemplary term "over" may include both orientations "above" and "below." The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Embodiment 1

A socket-type multi-layer pipe with end cladding, as shown in Figures 1 to 3, includes an inner tube 2, an intermediate layer 3 and an outer tube 1. The inner tube 2 includes an inner sleeve 21 and two edgings 22. The sleeve 21 and the two edges 22 are integrated, the inner sleeve 21 is cylindrical, and the inner sleeve 21, the middle layer 3 and the outer tube 1 are connected in sequence from the inside to the outside.

The outer tube 1 includes a socket portion 11 , a straight tube portion 12 and a spigot portion 13 that are connected in sequence along its axial direction, that is, the socket portion 11 , the straight tube portion 12 and the spigot portion 13 share a center line. Both the straight tube part 12 and the socket part 13 are cylindrical, and the end of the socket part 13 away from the straight tube part 12 is chamfered along the circumferential direction. The inner surface of the socket portion 11 is provided with steps and/or grooves, that is, the socket portion 11 can be considered to be composed of a plurality of cylindrical structures with different inner diameters connected in sequence.

The outer tube 1 is made of metal, preferably ductile iron or carbon steel. Preferably, the socket part 11, the straight tube part 12 and the socket part 13 are integrally cast, or the straight tube part 12 and the socket part 13 are integrally formed as a pipe body, and the pipe body and the socket part 11 are manufactured separately and then welded together. . The inner diameter, outer diameter, and thickness of the socket portion 13 are substantially equal to the inner diameter, outer diameter, and thickness of the straight tube portion 12 respectively.

The inner tube 2 is made of corrosion-resistant materials, including but not limited to stainless steel, titanium, and composite materials, preferably stainless steel. One end of the inner tube 2 covers the end surface of the straight tube portion 12 close to the socket portion 11 , the middle portion of the inner tube 2 covers the inner wall of the straight tube portion 12 and the inner wall of the socket portion 13 , and the other end of the inner tube 2 covers the socket portion 13 End face. Specifically, the inner sleeve 21 covers the inner wall of the straight tube portion 12 and the inner wall of the socket portion 13 , one edge 22 covers the end surface of the socket portion 13 , and the other edge 22 covers the end surface of the straight tube portion 12 . It can be seen from the above that the inner tube 2 has no holes and is a continuous medium, which can completely cover the end and inner wall of the straight tube portion 12 and the inner wall and end surface of the socket portion 13 .

The middle layer 3 is made of a material with insulation function, preferably plastic, and is located between the inner sleeve 21 and the outer tube 1 .

There is a sealing gasket 4 between the end surface of the socket part 13 and one of the wrapping edges 22 , and there is a sealing gasket 4 between the end surface of the straight tube part 12 and the other wrapping edge 22 .

As shown in Figures 1 to 3, the sealing gasket 4 includes an integrally connected flange 41 and a flange 42. The flange 41 can be regarded as a thin cylindrical shape, and the flange 42 is annular. The inner diameter of the flange 42 is equal to the inner diameter of the flange 41 , and the outer diameter of the flange 42 is larger than the outer diameter of the flange 41 . The edge 41 and the flange 42 share a center line. At one end of the socket portion 13, the crimp 41 is located between the inner wall of the socket portion 13 and the inner sleeve 21, and the flange 42 is located between the end surface of the socket portion 13 and the wrapping edge 22 covering the end surface. , the flange 41 is located between the inner wall of the straight tube portion 12 and the inner sleeve 21 , and the flange 42 is located between the end surface of the straight tube portion 12 and the wrapping edge 22 covering the end surface.

It should be noted that the crimp 41 can be eliminated. As shown in FIG. 1 , the sum of the lengths of the straight tube portion 12 and the socket portion 13 , the length of the inner sleeve 21 , and the length of the middle layer 3 are equal. One end surface of the intermediate layer 3 is flush with the end surface of the socket portion 13 , and the other end surface of the intermediate layer 3 is flush with the end surface of the straight tube portion 12 . At this time, the sealing gasket 4 is equivalent to only having a flange 42 and no crimp 41 . As shown in Figures 2 and 3, one end surface of the middle layer 3 is not flush with the end surface of the socket portion 13, and the end surface of the socket portion 13 exceeds one end surface of the middle layer 3. At this time, the sealing gasket 4 has both a flange 42 and a pressure edge 41. . In the same way, the other end surface of the middle layer 3 is not flush with the end surface of the straight tube portion 12 .

Sealing gasket 4 is a rubber gasket. The sealing gasket 4 prevents the liquid in the pipeline from contacting the end surface of the spigot part 13 or the middle layer of the end surface of the straight pipe part 12, and the liquid penetrates into the inner wall of the outer pipe 1, causing corrosion of the inner wall of the outer pipe 1 and contaminating the transported liquid.

The inner wall of the socket portion 11 is provided with a step. The inner wall of the step closest to the straight tube portion 12 is the outer surface of the truncated cone. That is, the inner diameter of this step gradually increases from the socket portion 11 toward the straight tube portion 12 . , equivalent to a bell mouth, this setting is to provide a deflection angle for the adjacent multi-layer pipes connected to it, that is, to allow the center line of a multi-layer pipe and the center line of the adjacent multi-layer pipes connected to it to be at The intersecting state, rather than the coincident state, is to allow a certain installation error and facilitate actual operation.

The outer diameter of the inner sleeve 21 is slightly smaller than the inner diameter of the outer tube 1, and the thickness of the inner sleeve 21 is not less than 0.1mm.

The main function of the inner sleeve 21 is anti-corrosion, and the thickness should not be large. A large number of welding tests have shown that under the conditions of fiber laser welding process, stainless steel plates can obtain welds with high welding strength and small deformation under the minimum wall thickness of 0.1mm. .

The wall thickness of the middle layer 3 is not less than 0.2mm. The middle layer 3 also serves as an insulating layer and requires a certain thickness to produce an insulating effect between the outer tube 1 and the inner sleeve 21. The spark test shows that when the thickness of the middle layer 3 is not less than 0.2mm, a stable and better performance can be obtained Insulation.

The inner diameter of the middle layer 3 is slightly larger than the outer diameter of the inner tube 2 , and the outer diameter of the middle layer 3 is slightly smaller than the inner diameter of the outer tube 1 . The length of the middle layer 3 is basically the same as the length of the inner sleeve 21 .

In this embodiment, the thickness of the inner sleeve 21 and the thickness of the edge 22 are equal. The two ends of the inner sleeve 21 are integrally connected to the two hems 22 respectively, and the two ends of the inner tube 2 are respectively flanged to form two hems 22 at both ends and an inner sleeve 21 in the middle.

A method of manufacturing an end-clad socket-type multi-layer pipe, which is used to manufacture the pipe, including the following steps:

Step S1: Process the inner wall and outer wall of the outer tube 1, make the inner tube 2, and make the middle layer 3.

In this step, the method for processing the inner wall and the outer wall of the outer pipe 1 is to first grind the inner wall of the outer pipe 1 and then sandblast or shot blast the inner wall and the outer wall. Use an internal grinder to grind the inner wall of the outer tube 1 to smooth the inner wall and remove surface oxide scale, scum, rust, etc. Alternatively, after grinding the inner wall flat, use a laser cleaning machine to clean the inner wall of the pipe to deeply remove the oxide scale and rust on the inner wall of the pipe. During sandblasting or shot blasting, dust, oxide scale, and rust on the inner and outer walls are removed, and the inner and outer walls of the pipe are sandblasted to form a frosted surface.

Making inner tube 2 includes the following steps:

S11: Process the stainless steel sheet into a ring shape or a thin cylindrical shape, and complete the rounding. In this step, the rounding is performed by a rounding machine.

S12: Cut the rolled stainless steel sheet and weld it into a cylindrical shape. In this step, if what is obtained in step S11 is a single rolled circle whose length is greater than the length of the inner pipe 2, use an argon arc welding machine or a laser welder to perform straight seam welding, and the weld seam extends from one end of the inner pipe 2 to the other end. . If what is obtained in step S11 is a plurality of spirally connected rolled circles, a spiral seam welding machine is used to weld the plurality of spirally connected rolled circles in sequence to form a thin cylindrical shape.

Preferably, the length of the stainless steel round pipe obtained in step S12 is not less than the length of the inner pipe 2 of the pipe that is finally processed. Specifically, the length of the stainless steel round pipe obtained in step S12 is not less than the sum of the length of the straight pipe part 12 , the length of the socket part 13 , and the length of the two edges 22 .

S13: Flange one end of the stainless steel inner tube 2 to form a hemming 22, and sleeve a sealing gasket 4 on the outer wall of the inner tube 2, with one end surface of the sealing gasket 4 contacting the hemming 22. The sealing gasket 4 can be bonded to the edge 22 with glue according to specific circumstances. In this step, the existing pipe flanging machine is used to perform the flanging operation.

Step S2: Arrange the inner tube 2, the middle layer 3 and the outer tube 1 in sequence from the inside to the outside.

In this step, step S3 can be completed in the following three ways:

The first way is as follows:

First, the plastic is formed into a round tube through extrusion molding, vacuum sizing, traction, and cutting. Extruders, vacuum boxes, traction machines, and cutting machines in the existing technology can be used to perform extrusion molding, vacuum sizing, traction, and cutting respectively. The extrusion molding is an existing technology and will not be described in detail here.

Then, the obtained formed intermediate layer 3 is sleeved on the outer wall of the inner tube 2 . In this step, casing can be performed manually or with an existing casing machine.

Finally, the intermediate layer 3 and the inner tube 2 that are sheathed together are inserted into the outer tube 1 as a whole. Similarly, in this step, the casing can be completed manually or with a tube threading machine. Insert the end of the inner tube 2 that has not been wrapped 22 into the outer tube 1 from the end of the socket 11 until the existing edge 22 presses the sealing gasket 4 against the end of the straight tube 12 at one end of the socket 11 department.

The second way is as follows:

First, after the inner wall of the straight tube part 12 and the inner wall of the socket part 13 are heated, the powdered plastic is rotomolded or spray-molded on the inner wall of the straight tube part 12 and the inner wall of the socket part 13 using a roller coating machine or a coating machine.

Then, the inner tube 2 is inserted into the outer tube 1 with the intermediate layer 3 on the inner wall.

It should be noted that when the sealing gasket 4 used includes a flange 41 and a flange 42, during rotational molding or spray molding, the circle where the flange 41 is installed should be covered with stainless steel to prevent the area where the flange 41 is installed from being sprayed. Applying plastic powder will affect the subsequent installation of the edge holder 41.

The third way is as follows:

First, after the outer wall of the inner tube 2 is heated, the powdered plastic is rotomolded or spray-molded on the outer wall of the inner sleeve 21 of the stainless steel inner tube 2 using a roller coating machine or a plastic coating machine.

Then, the inner tube 2 with the intermediate layer 3 on the outer wall is inserted into the outer tube 1 .

Step S3: Press the inner tube 2 and the middle layer 3 onto the outer tube 1.

This step can be accomplished by spin forming or hydroforming. During spin forming, a pipe spinning machine is used to spin the inner tube 2 so that the stainless steel-lined inner sleeve 21, the middle layer 3, and the outer tube 1 are in close contact with each other in sequence. During hydroforming, both ends of the inner tube 2 that penetrates the outer tube 1 are sealed, and water is injected into the tube to pressurize the inner sleeve 21, the middle layer 3, and the outer tube 1 in order.

Step S4: Flange both ends of the inner tube 2.

In this step, when the middle layer 3 is made of plastic, step S13 is performed. At this time, it is only necessary to flange and seal one end of the socket portion 13 of the inner tube 2 . First, put the sealing gasket 4 on the outer wall of the inner tube 2 that exceeds the end surface of the socket portion 13 and make the sealing gasket 4 close to the end surface of the socket portion 13 . Then, use a crimping device to crimp the portion of the inner tube 2 that exceeds the sealing gasket 4, so that the portion of the inner tube 2 that exceeds the sealing gasket 4 is flanged, even if the original outer wall of the portion of the inner tube 2 that exceeds the sealing gasket 4 is close to the sealing gasket 4 , the original inner wall becomes the end of the pipe, and the stainless steel forming one end of the pipe insertion part 13 is the edge 22 .

Step S5: Tighten the hemming 22 and trim the edges.

In this step, the stainless steel flanges (i.e., the edges 22) at both ends of the pipe are tightened against the end faces of the spigot portion 13 and the straight pipe portion 12 using a tightening device. Trim off excess sealing gaskets and stainless steel at both ends of the pipe.

After completing the above steps, spray paint or plastic coat the outer wall of the pipe or perform external anti-corrosion treatment in other ways.

Embodiment 2

Different from the first embodiment, as shown in Figures 4 to 6, in this embodiment, the hemming 22 is not formed by flanging the inner tube 2, but is made separately, and is then welded to the inner sleeve 21 to form an inner tube 2. The two ends of the tube 2, that is, the inner sleeve 21, are welded to the two edges 22 respectively. The material of the edge wrapping 22 and the inner sleeve 21 is the same, and both are corrosion-resistant materials, preferably stainless steel.

In this embodiment, the length of the inner sleeve 21 is less than the sum of the length of the straight pipe part 12 and the length of the socket part 13. The welding points B (weld seams) of the two ends of the inner sleeve 21 and the two edges 22 are located on the pipe. on the inner wall.

As shown in Figure 6, the hemming 22 includes an integrally connected hemming press 221 and a hemming flange 222. The hemming press 221 can be regarded as a thin cylinder, and the hemming flange 222 is annular. . The inner diameter of the wrapping flange 222 is equal to the inner diameter of the wrapping flange 221 , and the outer diameter of the wrapping flange 222 is larger than the outer diameter of the wrapping flange 221 . The hemming press 221 and the hemming flanging 222 share a center line. At one end of the socket part 13, the wrapping flange 222 is located on the end surface of the socket part 13 and presses the sealing gasket 4 on the end surface of the socket part 13. The wrapping flange 221 is located on the inner wall of one end of the pipe socket part 13 and presses the socket. The sealing gasket 4 and/or the intermediate layer 3 on the inner wall of the part 13. For one end of the socket part 11, the wrapping flange 222 is located on the end surface of the straight tube part 12, pressing the sealing gasket 4 on the end surface of the straight tube part 12, and the wrapping flange 221 is located on the inner wall of one end of the straight tube part 12. , press the sealing gasket 4 and/or the intermediate layer 3 on the inner wall of the straight pipe part 12.

In this embodiment, the thickness of the hemming 22 is greater than the thickness of the inner sleeve 21 .

In this embodiment, the length H of the hemming and pressing edge 221 is not less than 20 mm.

Based on the above structure, the manufacturing method of this embodiment is different from that of Embodiment 1. The manufacturing method includes the following steps.

Step S1: Process the inner wall and outer wall of the outer tube 1, make the inner sleeve 21, make the wrapping 22, and make the middle layer 3.

A rolling machine is used to make the wrapping 22, which includes a wrapping press 221 and a wrapping flange 222. The inner diameter of the edging 22 is substantially equal to the inner diameter of the inner sleeve 21 , and the thickness of the edging 22 is greater than the thickness of the inner sleeve 21 .

Step S2: Arrange the inner sleeve 21, the middle layer 3 and the outer tube 1 in sequence from the inside to the outside.

Step S3: Press the inner tube 2 and the middle layer 3 onto the outer tube 1.

Step S4: Put the two wrapping edges 22 into one end of the socket part 13 and the end of the straight tube part 12 close to the socket part 11 respectively, and weld the two ends of the inner sleeve 21 to the two wrapping edges 22 respectively.

Finally, it is necessary to explain here that the above examples are only used to further explain the technical solution of the present invention in detail and cannot be understood as limiting the protection scope of the present invention. Those skilled in the art will make some decisions based on the above content of the present invention. Non-essential improvements and adjustments belong to the protection scope of the present invention.

Claims (16)

1. A socket-type multi-layer pipe with end cladding, characterized in that it includes an inner pipe (2), an intermediate layer (3) and an outer pipe (1). The intermediate layer (3) is made of a material with an insulating function. The inner tube (2) is made of corrosion-resistant material. The outer tube (1) includes a socket portion (11), a straight tube portion (12) and a socket portion (13) connected in sequence. The inner tube (2) ) covers the end surface of the spigot part (13) and the other end covers the end surface of the straight tube part (12). The inner tube (2), the middle layer (3) and the outer tube (1) are pressed together to form the pipe. 2. The multi-layer pipe according to claim 1, characterized in that: the inner tube (2) includes an inner sleeve (21) and two edges (22), and the inner sleeve (21) and two edges (22) As a whole, the inner sleeve (21), the middle layer (3) and the outer tube (1) are connected in sequence from the inside to the outside. 3. The multi-layer pipe according to claim 2, characterized in that: the end surface of the socket part (13) is covered by a sealing gasket (4), and the end surface of the straight pipe part (12) is covered by another sealing gasket (4) Cover and edge (22) press the sealing gasket (4). 4. The multi-layer pipe according to claim 3, characterized in that: the sealing gasket (4) at one end of the socket portion (13) is pressed tightly by a wrapping (22) and the upper end surface of the sealing gasket (4) does not exceed the wrapping. The upper end surface of the covered edge (22), the sealing gasket (4) at one end of the straight pipe portion (12) is pressed tightly by the other edge (22), and the upper end surface of the sealing gasket (4) does not exceed the covered edge. The upper end surface of the hemming (22). 5. The multi-layer pipe according to claim 3, characterized in that: both ends of the inner tube (2) are flanged to form two edges (22) at both ends, and the inner sleeve (21) covers the straight tube portion ( 12) and the inner wall of the socket part (13), the two wrapping edges (22) respectively press the sealing gasket (4) on the end face of the socket part (13) and the sealing gasket (4) on the end face of the straight tube part (12). 6. The multi-layer pipe according to claim 3, characterized in that: the length of the inner sleeve (21) is less than the sum of the length of the straight pipe portion (12) and the length of the socket portion (13), and the length of the inner sleeve (21) and The two edges (22) are welded. 7. The multi-layer pipe according to claim 6, characterized in that: the thickness of the edge (22) is greater than the thickness of the inner sleeve (21). 8. The multi-layer pipe according to claim 6, characterized in that: the hemming (22) includes an integrally connected hemming press (221) and a hemming flanging (222), at one end of the socket portion (13), The hemming and flanging (222) presses the sealing gasket (4) on the end face of the socket part (13), and the hemming and flanging (221) is located on the inner wall of one end of the pipe socket part (13) and presses the socket part (13) The sealing gasket (4) and/or the middle layer (3) on the inner wall is at one end of the socket portion (11), and the flanging (222) presses the sealing gasket (4) on the end face of the straight pipe portion (12). The hemming and crimping (221) is located on the inner wall of one end of the straight pipe portion (12) of the pipe and compresses the sealing gasket (4) and/or the middle layer (3) on the inner wall of the straight pipe portion (12). 9. The multi-layer pipe according to claim 8, characterized in that: the length of the hemming and crimping (221) is not less than 20 mm. 10. The multi-layer pipe according to claim 1, characterized in that: the material of the middle layer (3) is plastic, and the material of the outer pipe (1) is metal. 11. The multi-layer pipe according to claim 10, characterized in that: the outer pipe (1) is made of ductile iron or carbon steel. 12. The multi-layer pipe according to claim 10, characterized in that: the thickness of the middle layer (3) is not less than 0.2mm, and the thickness of the inner sleeve (21) is not less than 0.1mm. 13. A method of manufacturing an end-clad socket-type multi-layer pipe, used to manufacture the multi-layer pipe according to any one of claims 1 to 12, characterized in that it includes the following steps: Step S1: Process the inner and outer walls of the outer tube (1), make the inner tube (2), and make the middle layer (3); Step S2: Arrange the inner tube (2), the middle layer (3) and the outer tube (1) in sequence from the inside to the outside; Step S3: Press the inner tube (2) and the middle layer (3) onto the outer tube (1); Step S4: Set the wrapping (22) at both ends of the inner tube (2) so that the wrapping (22) covers the end surface of one end of the socket portion (13) and the end surface of the straight tube portion (12) of the pipe. 14. The manufacturing method according to claim 13, characterized in that: in step S3, the inner tube (2) is tightly pressed against the inner wall of the outer tube (1) through spin forming or hydraulic forming. 15. The manufacturing method according to claim 13, characterized in that: in step S1, the inner tube (2) can be made as a whole, and then in step S4, both ends of the inner tube (2) are flanged to form a hemming ( 22); or in step S1, the inner sleeve (21) and the hemming (22) are separately produced, and then in step S4, the inner sleeve (21) and the hemming (22) are welded together. 16. The manufacturing method according to claim 15, characterized in that when the inner sleeve (21) and the hemming (22) are welded, the welding point is located on the inner wall of the pipe.