Expanded connection quality detection device for double-layer pipe

Abstract

The utility model provides an expanded connection quality detection device for a double-layer pipe, which relates to the technical field of double-layer pipe preparation and comprises a first drawing piece, a second drawing piece and a detection device, wherein the first end of the first drawing piece is provided with a first abutting part which is used for abutting against the end face of an inner-layer pipe at the first end of the to-be-tested double-layer pipe; the to-be-tested double-layer pipe is used for being arranged on the inner circumferential wall of the second drawing piece in a sleeving manner; the first end of the second drawing piece is provided with a second abutting part used for abutting against the outer-layer pipe end face of the second end of the to-be-tested double-layer pipe. Wherein the inner-layer pipe and the outer-layer pipe of the double-layer pipe to be detected are drawn in opposite directions, and expanded connection quality detection is carried out. The device is used for detecting the expanded connection quality of the double-layer pipe, so that the double-layer pipe with better expanded connection quality can be bent and formed, and the relative sliding of the inner-layer pipe and the outer-layer pipe in the bending process can be avoided.

Description

Technical Field

[0001] This utility model belongs to the field of double-layer tube preparation technology, specifically relating to a device for detecting the expansion joint quality of double-layer tubes. Background Technology

[0002] In pipeline systems, cracks or breaks in pipes can cause major safety accidents. Double-layer composite metal pipes can effectively protect energy transmission and other media from leaks, and are a new type of important structural component that improves equipment reliability.

[0003] The spatial bending configuration of the inner and outer (layer) tubes must be considered during the forming process of double-layer tubes, making their manufacturing difficulty far exceed that of traditional methods. Therefore, an internal high-pressure forming method is used to bulge the inner tube, allowing it to adhere to the outer tube and continue bulging until the required dimensions are achieved, thus obtaining the double-layer tube.

[0004] In practical applications, when bending double-layer tubes, to ensure the quality of the bent product, it is necessary to ensure high-quality expansion joints to avoid relative slippage between the inner and outer tubes during bending. Therefore, it is necessary to inspect the expansion joint quality of the double-layer tubes before bending. However, existing technologies lack devices for inspecting the expansion joint quality of double-layer tubes. Utility Model Content

[0005] Therefore, this utility model provides a device for detecting the expansion joint quality of double-layer pipes, in order to solve the problem that there is no device for detecting the expansion joint quality of double-layer pipes in the prior art.

[0006] To address the aforementioned problems, this utility model provides a device for detecting the expansion joint quality of double-layer pipes, the device comprising:

[0007] The first drawing member, the double-layer tube to be tested is used to be sleeved on the outer peripheral wall of the first drawing member; wherein, the first end of the first drawing member is provided with a first abutting part, which is used to abut the end face of the inner layer tube of the first end of the double-layer tube to be tested.

[0008] The second drawing member is used to fit the double-layer tube to be tested onto the inner circumferential wall of the second drawing member; the first end of the second drawing member is provided with a second abutment part, which is used to abut against the outer tube end face of the second end of the double-layer tube to be tested;

[0009] Specifically, the double-layer tube to be tested is clamped between the outer peripheral wall of the first puller and the inner peripheral wall of the second puller by the first puller and the second puller, so as to realize the inner and outer tubes of the double-layer tube to be tested being pulled in opposite directions to perform expansion joint quality detection.

[0010] Furthermore, the first drawing member has a rod-shaped structure.

[0011] Furthermore, the first abutting part is a first step structure disposed at the first end of the first drawing member; wherein, the step surface of the first step structure is used to abut against the end face of the inner tube of the first end of the double-layer tube to be tested.

[0012] Preferably, the height h1 of the step surface of the first step structure is less than or equal to the thickness of the inner tube in the double-layer tube to be tested; more preferably, the height h1 of the step surface of the first step structure is greater than or equal to half the thickness of the inner tube in the double-layer tube to be tested.

[0013] Preferably, the first stepped structure is arranged in a ring around the first end of the first drawing member;

[0014] Preferably, the first abutting part and the first pulling member are an integral structure.

[0015] Furthermore, the second drawing member has a tubular structure.

[0016] Furthermore, the second abutting part is a second step structure disposed at the second end of the second drawing member; wherein, the step surface of the second step structure is used to abut against the end face of the outer tube at the second end of the double-layer tube to be tested;

[0017] Preferably, the height h2 of the step surface of the second step structure is less than or equal to the thickness of the outer tube in the double-layer tube to be tested; more preferably, the height h2 of the step surface of the second step structure is greater than or equal to half the thickness of the outer tube in the double-layer tube to be tested.

[0018] Preferably, the second stepped structure is arranged in a ring around the first end of the second drawing member;

[0019] Preferably, the second abutting part and the second pulling member are an integral structure. 。

[0020] Furthermore, the first drawing member includes a first end, a second end, and a main body portion located between the first end and the second end;

[0021] The first end of the first drawing member is a frustum-shaped structure with one end larger than the other; wherein, the larger end of the frustum-shaped structure is connected to the main body; the smaller end of the frustum-shaped structure is the first end of the first drawing member;

[0022] Preferably, the cross-sectional area of ​​the larger end of the frustum-shaped structure is larger than the cross-sectional area of ​​the main body, so that the larger end forms a stepped surface relative to the main body, serving as the first abutment portion;

[0023] Preferably, the first puller is an integral structure.

[0024] Furthermore, the double-layer tube expansion joint quality detection device also includes:

[0025] A first pull-out bolt is connected to the second end of the first pull-out member; wherein the second end and the first end of the first pull-out member are oppositely disposed ends;

[0026] The second pull bolt is connected to the second end of the second pull member; wherein the second end and the first end of the second pull member are opposite to each other.

[0027] Furthermore, the second end of the first pull member is provided with a first connecting structure for connecting the first pull bolt; preferably, when the first pull member is a rod-shaped structure, the first connecting structure is a connecting groove provided on the second end of the first pull member; the first pull bolt is threadedly connected to the connecting groove.

[0028] Furthermore, the second end of the second pull member is provided with a second connecting structure for connecting the second pull bolt; preferably, when the second pull member is a tubular structure, the second connecting structure is a thread provided on the second end of the second pull member; the second pull bolt is connected to the second pull member through the thread.

[0029] Furthermore, the first pull-out bolt is used to connect to the tensile testing machine; the second pull-out bolt is used to connect to the tensile testing machine.

[0030] The expansion joint quality testing device for double-layer tubes provided by this utility model has the following beneficial effects:

[0031] 1. This utility model provides a device for detecting the expansion joint quality of a double-layer tube, comprising: a first pulling member, wherein the double-layer tube to be tested is fitted onto the outer peripheral wall of the first pulling member; wherein the first end of the first pulling member is provided with a first abutting portion for abutting the end face of the inner layer tube of the first end of the double-layer tube to be tested; a second pulling member, wherein the double-layer tube to be tested is fitted onto the inner peripheral wall of the second pulling member; the first end of the second pulling member is provided with a second abutting portion for abutting the end face of the outer layer tube of the second end of the double-layer tube to be tested; wherein the double-layer tube to be tested is clamped between the outer peripheral wall of the first pulling member and the inner peripheral wall of the second pulling member by the first pulling member and the second pulling member, so as to realize the pulling of the inner and outer layers tubes of the double-layer tube to be tested in opposite directions for detecting the expansion joint quality; the device for detecting the expansion joint quality of the double-layer tube is used to detect the expansion joint quality of the double-layer tube, ensuring that the double-layer tube with good expansion joint quality is bent and formed, so as to avoid the relative sliding of the inner and outer layers tubes during bending, thereby ensuring the quality of the bent and formed product.

[0032] 2. Furthermore, in this utility model, the height h1 of the step surface of the first step structure is less than or equal to the thickness of the inner tube in the double-layer tube to be tested, and greater than or equal to half the thickness of the inner tube in the double-layer tube to be tested; the height h2 of the step surface of the second step structure is less than or equal to the thickness of the outer tube in the double-layer tube to be tested, and greater than or equal to half the thickness of the outer tube in the double-layer tube to be tested; through the above settings, on the one hand, it is convenient to apply the pulling force, and on the other hand, it can avoid the first end of the mandrel from contacting the outer tube during the pulling process, thereby ensuring that the pulling process proceeds smoothly. Attached Figure Description

[0033] To more clearly illustrate the embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0034] Figure 1 This is a process flow diagram of the preparation of the double-layer tube of this utility model; wherein: a is a schematic diagram of the assembly of the outer layer tube and the inner layer tube; b is a schematic diagram of the inner layer tube being bonded to the outer layer tube; c is a schematic diagram of the outer layer tube being bonded to the mold;

[0035] Figure 2 This is an assembly structure diagram of the double-layer tube expansion joint quality detection device of this utility model;

[0036] Figure 3 This is an assembly flowchart of the double-layer tube expansion joint quality detection device of this utility model; wherein: a is an assembly diagram of the mandrel and the double-layer tube to be tested; b is an assembly diagram of the bushing; c is an assembly diagram of the mandrel pull-out bolt and bushing pull-out.

[0037] Figure 4 a and 4b are schematic diagrams showing the expansion joint quality test results of the first and second double-layer tubes to be tested in Experimental Embodiment 1 of this utility model, respectively.

[0038] Figure 5 This is a schematic diagram of the expansion joint quality test results of the double-layer tube in Experimental Example 2 of this utility model;

[0039] Figure 6 This is a schematic diagram of the bending and forming of the double-layer tube in Experimental Embodiment 2 of this utility model;

[0040] Figure 7 for Figure 3 A magnified view of part of a;

[0041] Figure 8 for Figure 3 A magnified view of part b;

[0042] The attached figures are labeled as follows:

[0043] 1. Inner tube; 2. Outer tube; 3. Mold; 4. First drawing component; 5. Second drawing component; 6. First drawing bolt; 7. Second drawing bolt. Detailed Implementation

[0044] To more clearly illustrate the embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0045] If the expansion joint quality is not characterized and measured during the bending process of double-layer tubes, slippage may occur between the inner and outer tubes due to low expansion joint quality. Therefore, this utility model provides a device for detecting the expansion joint quality of double-layer tubes, which can use the detection results of the expansion joint quality of double-layer tubes as the basis for determining whether the inner and outer tubes do not undergo relative displacement under a specific bending radius.

[0046] The present invention will be described below through embodiments:

[0047] Example 1

[0048] like Figure 2 As shown, this embodiment provides a device for detecting the expansion joint quality of double-layer pipes. The device includes:

[0049] The first drawing member 4 is used to sleeve the double-layer tube to be tested on the outer peripheral wall of the first drawing member 4; wherein, the first end of the first drawing member 4 is provided with a first abutting part for abutting the end face of the inner tube 1 of the first end of the double-layer tube to be tested; the second drawing member 5 is used to sleeve the double-layer tube to be tested on the inner peripheral wall of the second drawing member 5; the first end of the second drawing member 5 is provided with a second abutting part for abutting the end face of the outer tube 2 of the second end of the double-layer tube to be tested;

[0050] Specifically, the double-layer tube to be tested is clamped between the outer peripheral wall of the first puller 4 and the inner peripheral wall of the second puller 5 by the first puller 4 and the second puller 5, so as to realize the inner and outer tubes of the double-layer tube to be tested being pulled in opposite directions for expansion joint quality detection.

[0051] The double-layer tube expansion joint quality detection device provided in this embodiment can determine the expansion joint quality of the double-layer tube by the magnitude of the pull-out force, so as to select the double-layer tube with higher expansion joint quality for bending and forming, thereby avoiding relative slippage between the inner and outer tubes during bending and ensuring the quality of the bent and formed product.

[0052] Example 2

[0053] Preferably, this embodiment provides a device for detecting the expansion joint quality of double-layer tubes, which, compared with Embodiment 1, offers advantages such as... Figure 3 As shown, in this embodiment, the first drawing member, the second drawing member, the first abutting part, and the second abutting part are further designed as follows:

[0054] The first drawing member 4 is a rod-shaped structure; the first abutting part is a first step structure disposed at the first end of the first drawing member 4; wherein, the step surface of the first step structure is used to abut against the end face of the inner tube 1 at the first end of the double-layer tube to be tested; the height h1 of the step surface of the first step structure is less than or equal to the thickness of the inner tube 1 in the double-layer tube to be tested, and greater than or equal to half the thickness of the inner tube 1 in the double-layer tube to be tested; the first step structure is disposed in a ring around the first end of the first drawing member 4; the first abutting part and the first drawing member 4 are an integral structure, see Figure 7 ;

[0055] The second drawing member 5 is a tubular structure; the second abutment is a second step structure located at the second end of the second drawing member 5; wherein, the step surface of the second step structure is used to abut against the end face of the outer tube 2 at the second end of the double-layer tube to be tested; the height h2 of the step surface of the second step structure is less than or equal to the thickness of the outer tube 2 in the double-layer tube to be tested, and greater than or equal to half the thickness of the outer tube 2 in the double-layer tube to be tested; the second step structure is arranged in a circle around the first end of the second drawing member 5; the second abutment and the second drawing member 5 are an integral structure, see Figure 8 。

[0056] In addition, the first drawing member 4 includes a first end, a second end, and a main body portion located between the first end and the second end; the first end of the first drawing member is a frustum-shaped structure with one end larger than the other; wherein, the larger end of the frustum-shaped structure is connected to the main body portion; the smaller end of the frustum-shaped structure is the first end portion of the first drawing member; preferably, the cross-sectional area of ​​the larger end of the frustum-shaped structure is larger than the cross-sectional area of ​​the main body portion, so that the larger end forms a stepped surface relative to the main body portion, serving as a first abutment portion; the first drawing member 4 is an integral structure.

[0057] In this embodiment, the first step structure, the second step structure, and the frustum-shaped structure facilitate the application of drawing force and prevent the first end of the first drawing member from contacting the outer tube during the drawing process, thereby ensuring the smooth progress of the drawing process.

[0058] Example 3

[0059] Preferably, this embodiment provides a device for detecting the expansion joint quality of double-layer tubes, which, compared with Embodiment 1, offers advantages such as... Figure 3 As shown, this embodiment is further designed as follows:

[0060] The double-walled pipe expansion joint quality inspection device also includes:

[0061] First pull-out bolt 6, the first pull-out bolt 6 is connected to the second end of the first pull-out member 4; wherein the second end and the first end of the first pull-out member 4 are opposite ends; second pull-out bolt 7, the second pull-out bolt 7 is connected to the second end of the second pull-out member 5; wherein the second end and the first end of the second pull-out member 5 are opposite ends;

[0062] The second end of the first drawing member is provided with a first connecting structure for connecting the first drawing bolt; preferably, when the first drawing member is a rod-shaped structure, the first connecting structure is a connecting groove 8 provided on the second end of the first drawing member; the first drawing bolt 6 is threadedly connected to the connecting groove 8; the second end of the second drawing member is provided with a second connecting structure for connecting the second drawing bolt; preferably, when the second drawing member is a tubular structure, the second connecting structure is a thread provided on the second end of the second drawing member; the second drawing bolt 7 is threadedly connected to the second drawing member 5; the first drawing bolt is used to connect to a tensile testing machine; the second drawing bolt is used to connect to a tensile testing machine.

[0063] In this embodiment, a tensile testing machine is used to perform a pull-out test to obtain the pull-out force (tensile force) during the pull-out process. The peak value of the force during the pull-out process characterizes the expansion joint quality of the double-layer tube.

[0064] The expansion joint quality is tested using any of the above-mentioned double-walled pipe expansion joint quality testing devices, such as... Figure 3 As shown, it includes the following steps:

[0065] Step 1): Place the double-layer tube to be tested on the outer peripheral wall of the first drawing member 4, so that the first abutting part on the first drawing member abuts against the end face of the inner tube 1 at the first end of the double-layer tube to be tested; place the double-layer tube to be tested on the inner peripheral wall of the second drawing member, so that the second abutting part on the second drawing member abuts against the end face of the outer tube 2 at the second end of the double-layer tube to be tested;

[0066] Step 2): Pull the first puller 4 away from the first end of the first puller 4 and pull the second puller 5 away from the first end of the second puller 5, so as to pull the inner tube and the outer tube of the double-layer tube under test in opposite directions. Based on the magnitude of the pulling force during the pulling process, the expansion joint quality test result of the double-layer tube under test is obtained.

[0067] Specifically, when different double-layer tubes were pulled out, under the same relative sliding displacement, the double-layer tube with a greater pulling force had better expansion joint quality.

[0068] Based on the method of this embodiment, by comparing the expansion quality of double-layer tubes of different materials, a double-layer tube with higher expansion quality can be selected for bending and forming, thereby avoiding relative slippage between the inner and outer tubes during bending and ensuring the quality of the bent and formed product.

[0069] The following method was used to process the expansion joint quality test results of the double-layer tube: When both the inner and outer layers are made of 304 stainless steel, and the maximum pull-out force is 1500N, the minimum bending radius obtained by finite element simulation for the double-layer tube without relative slippage between the inner and outer layers during bending is 84mm. Therefore, when the expansion joint quality test result of the double-layer tube is greater than 1500N, double-layer tube bending forming with a bending radius exceeding 84mm is possible.

[0070] The double-layer tube under test was prepared using a hydraulic expansion joint method, such as... Figure 1 As shown, the procedure includes the following steps: First, select two single-layer pipes of different diameters. Insert the smaller diameter pipe (inner layer) into the larger diameter pipe (outer layer). Then, place the inner and outer pipes into a (expansion) mold, as shown. Figure 1 As shown in diagram a; then the inner tube is sealed and filled with liquid for expansion, causing it to begin plastic deformation under internal pressure until it comes into contact with the outer tube, as shown in diagram a. Figure 1 As shown in b; continue applying pressure, causing the outer tube to expand and deform together with the inner tube under the pressure of the inner tube, until the two tubes fit together with the mold, as shown. Figure 1 As shown in c.

[0071] Experimental Example 1

[0072] This experimental embodiment uses the double-layer tube expansion joint quality detection device described in the above embodiment to detect the expansion joint quality of the first double-layer tube to be tested and the second double-layer tube to be tested, so as to select a double-layer tube that is more suitable for bending and forming.

[0073] The first and second double-layer tubes to be tested were both prepared using the following method: Two single-layer tubes of different diameters were selected, and the smaller diameter tube (inner tube) was inserted into the larger diameter tube (outer tube). Then, the inner and outer tubes were placed into a (expansion) mold. The inner tube was then sealed and filled with liquid for expansion, causing it to begin plastic deformation under internal pressure until it came into contact with the outer tube. Pressure was continued to be applied, causing the outer tube to expand together with the inner tube under the pressure of the inner tube until the double-layer tubes adhered to the mold. The internal pressure was 100 MPa. The outer tubes of the first and second double-layer tubes to be tested had the same dimensions, and the inner tubes of the first and second double-layer tubes had the same dimensions. Both the outer and inner tubes of the first double-layer tube were made of 304 steel. The outer tube of the second double-layer tube was made of 3004 aluminum, and the inner tube was made of 304 steel.

[0074] The specific steps for testing the expansion joint quality of the first and second double-layer tubes to be tested are as follows:

[0075] Step 1): Place the double-layer tube to be tested on the outer peripheral wall of the first drawing member, so that the first abutting part on the first drawing member abuts against the inner tube end face of the first end of the double-layer tube to be tested; place the double-layer tube to be tested on the inner peripheral wall of the second drawing member, so that the second abutting part on the second drawing member abuts against the outer tube end face of the second end of the double-layer tube to be tested.

[0076] Step 2): Pull the first puller away from the first end of the first puller and pull the second puller away from the first end of the second puller, so as to pull the inner and outer tubes of the double-layer tube under test in opposite directions. Based on the magnitude of the pulling force during the pulling process, the expansion joint quality test result of the double-layer tube under test is obtained.

[0077] The first puller has a first puller bolt threaded to its second end, and the second puller has a second puller bolt threaded to its second end. The first and second puller bolts are used to connect to a tensile testing machine. The tensile testing machine displays the magnitude of the tensile force.

[0078] The expansion joint quality test results of the first and second double-layer tubes under test, obtained according to this experimental embodiment, are as follows: Figure 4 As shown in 4a and 4b, it can be seen that under the same hydraulic expansion pressure, the expansion quality of the second double-layer tube under test is relatively higher than that of the first double-layer tube under test, and therefore it is more suitable for bending forming.

[0079] Experimental Example 2

[0080] This experimental embodiment uses the double-layer tube expansion joint quality detection device described in the above embodiment to detect the expansion joint quality of the double-layer tube under different hydraulic expansion joint internal pressures, so as to select a double-layer tube that is more suitable for bending and forming.

[0081] The double-layer tube to be tested was prepared using the following method: Two single-layer tubes of different diameters were selected, and the smaller diameter tube (inner tube) was inserted into the larger diameter tube (outer tube). Then, the inner and outer tubes were placed into a (expansion) mold. The inner tube was then sealed and filled with liquid to expand, causing it to begin to deform plastically under internal pressure until it came into contact with the outer tube. Pressure was then applied to the outer tube, causing it to expand together with the inner tube under the pressure of the inner tube until the double-layer tube fits the mold.

[0082] Among them, the outer tube of the double-layer tube to be tested is made of 3003 aluminum alloy, and the inner tube of the second double-layer tube to be tested is made of 304 steel; the internal pressure of hydraulic expansion is selected as 50MPa, 100MPa and 150MPa respectively;

[0083] The method for testing the expansion joint quality of the double-layer tube under different internal pressures includes the following steps:

[0084] Step 1): Place the double-layer tube to be tested on the outer peripheral wall of the first drawing member, so that the first abutting part on the first drawing member abuts against the inner tube end face of the first end of the double-layer tube to be tested; place the double-layer tube to be tested on the inner peripheral wall of the second drawing member, so that the second abutting part on the second drawing member abuts against the outer tube end face of the second end of the double-layer tube to be tested.

[0085] Step 2): Pull the first puller away from the first end of the first puller and pull the second puller away from the first end of the second puller, so as to pull the inner and outer tubes of the double-layer tube under test in opposite directions. Based on the magnitude of the pulling force during the pulling process, the expansion joint quality test result of the double-layer tube under test is obtained.

[0086] The first puller has a first puller bolt threaded to its second end, and the second puller has a second puller bolt threaded to its second end. The first and second puller bolts are used to connect to a tensile testing machine. The tensile testing machine displays the magnitude of the tensile force.

[0087] The expansion joint quality test results of the double-layer tube under different internal pressures obtained according to this experimental embodiment are as follows: Figure 5 As shown, it can be seen that when the internal pressure of hydraulic expansion is 150MPa, the expansion quality of the resulting double-layer tube is higher than that when the internal pressure of hydraulic expansion is 50MPa or 100MPa. That is, the expansion quality of the double-layer tube increases with the increase of the internal pressure during hydraulic expansion (hydraulic forming).

[0088] The double-layer tubes obtained by hydraulic expansion joints with internal pressures of 50 MPa and 150 MPa in this experimental embodiment were bent and formed, as follows: Figure 6 As shown, during the bending process, the inner and outer tubes of the double-layer tube obtained when the internal pressure of the hydraulic expansion joint is 50MPa slide relative to each other; while the inner and outer tubes of the double-layer tube obtained when the internal pressure of the hydraulic expansion joint is 150MPa do not slide relative to each other. Therefore, the double-layer tube obtained when the internal pressure of the hydraulic expansion joint is 150MPa is more suitable for bending, proving that the better the expansion joint quality, the higher the bending quality.

[0089] This invention employs a double-layer tube expansion joint quality testing device, which characterizes the expansion joint quality by comparing the peak force magnitude during the pulling process. Due to the different deformation amounts of the inner and outer tubes during the expansion process, residual elastic strain exists between the two layers. The contact between the two tubes is surface-to-surface, and the tube material rebounds due to deformation. The difference in the amount of rebound results in a certain contact force between the inner and outer tubes, thus generating friction. This creates frictional force between the expanded metal double-layer tubes. Based on f = μF, this device can measure the magnitude of the tensile force to reflect the magnitude of the frictional force. Figure 5It can be seen that as the internal pressure of the double-layer tube gradually increases, the peak tensile force required for the pulling operation also increases accordingly. This reflects that the frictional force also increases accordingly under this increase in internal pressure. This positive correlation between the peak tensile force, frictional force, and internal pressure proves that the expansion joint quality of the double-layer tube significantly improves with increasing internal pressure. This has extremely important guiding significance for the control and optimization of expansion joint quality in relevant engineering applications.

[0090] It will be readily understood by those skilled in the art that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0091] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model. The above description is only a preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A device for detecting the expansion quality of a double-pipe, characterized by, The expansion quality detection device of the double-layer pipe comprises: A first pulling piece (4) is used for sleeving the double-layer pipe to be detected on the outer peripheral wall of the first pulling piece (4); wherein the first end of the first pulling piece (4) is provided with a first abutting portion for abutting the end face of the inner layer pipe (1) of the first end of the double-layer pipe to be detected; A second pulling piece (5) is used for sleeving the double-layer pipe to be detected on the inner peripheral wall of the second pulling piece (5); the first end of the second pulling piece (5) is provided with a second abutting portion for abutting the end face of the outer layer pipe (2) of the second end of the double-layer pipe to be detected; Wherein, the double-layer pipe to be detected is clamped between the outer peripheral wall of the first pulling piece (4) and the inner peripheral wall of the second pulling piece (5) through the first pulling piece (4) and the second pulling piece (5) to realize the pulling of the inner layer pipe and the outer layer pipe of the double-layer pipe to be detected in opposite directions and the expansion quality detection.

2. The apparatus for testing expansion quality of a double tube according to claim 1, wherein The first pulling piece (4) is a rod structure.

3. The double tube expansion quality detecting apparatus according to claim 1 or 2, characterized by The first abutting portion is a first step structure arranged at the first end of the first pulling piece (4); wherein the step face of the first step structure is used for abutting the end face of the inner layer pipe (1) of the first end of the double-layer pipe to be detected; Wherein, the height h1 of the step face of the first step structure is less than or equal to the thickness of the inner layer pipe (1) in the double-layer pipe to be detected; the height h1 of the step face of the first step structure is greater than or equal to half of the thickness of the inner layer pipe (1) in the double-layer pipe to be detected; The first step structure is arranged around the first end of the first pulling piece (4) for one circle; The first abutting portion and the first pulling piece (4) are an integral structure.

4. The apparatus for testing expansion quality of a double tube according to claim 1, wherein The second pulling piece (5) is a tubular structure.

5. The apparatus according to claim 1 or 4, wherein The second abutting portion is a second step structure arranged at the second end of the second pulling piece (5); wherein the step face of the second step structure is used for abutting the end face of the outer layer pipe (2) of the second end of the double-layer pipe to be detected; Wherein, the height h2 of the step face of the second step structure is less than or equal to the thickness of the outer layer pipe (2) in the double-layer pipe to be detected; the height h2 of the step face of the second step structure is greater than or equal to half of the thickness of the outer layer pipe (2) in the double-layer pipe to be detected; The second step structure is arranged around the first end of the second pulling piece (5) for one circle; The second abutting portion and the second pulling piece (5) are an integral structure.

6. The apparatus for testing expansion quality of a double tube according to claim 1, wherein The first pulling piece (4) comprises a first end, a second end and a main body part between the first end and the second end; The first end of the first pulling piece is a circular truncated cone structure with one end large and the other end small; wherein the large end of the circular truncated cone structure is connected with the main body part; the small end of the circular truncated cone structure is the first end of the first pulling piece; Wherein, the cross-sectional area of the large end of the circular truncated cone structure is greater than the cross-sectional area of the main body part, so that the large end forms a step face relative to the main body part to serve as the first abutting portion; The first pulling piece (4) is an integral structure.

7. The apparatus for testing expansion quality of a double tube according to any one of claims 1 to 6, characterized by The expansion quality detection device of the double-layer pipe further comprises: A first drawing bolt (6) is connected to the second end of the first drawing member (4); wherein the second end and the first end of the first drawing member (4) are oppositely arranged; A second drawing bolt (7) is connected to the second end of the second drawing member (5); wherein the second end and the first end of the second drawing member (5) are oppositely arranged.

8. The apparatus according to claim 7, wherein The second end of the first drawing member is provided with a first connecting structure for connecting the first drawing bolt; When the first drawing member is in a rod-like structure, the first connecting structure is a connecting groove (8) arranged on the second end of the first drawing member; the first drawing bolt (6) is threadedly connected with the connecting groove (8).

9. The apparatus according to claim 7, wherein The second end of the second drawing member is provided with a second connecting structure for connecting the second drawing bolt; When the second drawing member is in a tube-like structure, the second connecting structure is a thread arranged on the second end of the second drawing member; the second drawing bolt (7) is connected with the second drawing member (5) through the thread.

10. The apparatus for testing expansion quality of a double tube according to claim 7, wherein The first drawing bolt is used for connecting a tensile testing machine; and the second drawing bolt is used for connecting the tensile testing machine.

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