Variable cross-section calabash-shaped corrugated pipe and preparation process thereof

Abstract

The variable-cross-section gourd-shaped corrugated pipe comprises a pipe body, and a plurality of corrugated structural bodies are arranged in the middle of the pipe body in a composite and stacked mode in the longitudinal direction; the corrugated structural body is composed of a side wall arc structure and a spherical shell radius structure, and the corrugated structural body forms a gourd shape through the side wall arc structure and the spherical shell radius structure. According to the corrugated pipe, the pipe body forms a corrugated pipe structure through the multiple corrugated structural bodies arranged in the longitudinal composite stacking mode, by adjusting radius data of the side wall arc structure and the spherical shell radius structure, compared with a U-shaped wave, the side wall of the wave form is reinforced, the radius of the arc spherical shell can be decreased, and therefore the pressure resistance of the corrugated pipe is improved, and the service life of the corrugated pipe is prolonged. According to the composite corrugated pipe, the compression ratio of a single wave is increased, a plurality of composite corrugated pipes are adopted, and a plurality of diaphragm shapes with different arcs are flexibly composited and superposed according to a certain rule, so that the pressure resistance, the displacement amount per unit length and the overall axial rigidity of the corrugated pipe are improved.

Description

Technical Field

[0001] The invention relates to the field of metal bellows, in particular to a variable-section gourd-shaped bellows and a preparation process thereof. Background Art

[0002] Metal bellows is a kind of pipe with regular wave pattern, which is used for connecting pipes and equipment in situations where small bending radius and non-concentric axial transmission are required and it is not convenient to install with fixed elbows.

[0003] At present, the waveforms of hydraulically formed metal bellows on the market are mostly U-shaped, while single-layer and double-layer S-shaped bellows are made by welding stamped diaphragms. Among them, when preparing the U-shaped bellows, its outer wall needs to be set with a mesh sleeve, and the side wall of this type of U-shaped bellows does not change, so that its single-wave compression ratio is small and the axial stiffness is large, which makes its pressure resistance insufficient. The diaphragm welded bellows weld the diaphragms one by one in the outer circle and the inner circle respectively, which will increase the number of welds and make it impossible to ensure the sealing of the pipe body. Therefore, this scheme proposes a variable-section gourd-shaped bellows and its preparation process. Summary of the invention

[0004] The object of the present invention is to provide a gourd-shaped corrugated pipe with a variable cross-section and a preparation process thereof, so as to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a variable-section gourd-shaped corrugated pipe, comprising a pipe body, wherein a plurality of corrugated structures are compositely stacked and arranged in the middle of the pipe body along the longitudinal direction;

[0006] The corrugated structure is composed of a side wall arc structure and a spherical shell radius structure, and the corrugated structure is formed into a gourd shape by the side wall arc structure and the spherical shell radius structure.

[0007] Preferably, the spherical shell radius structure comprises a spherical shell structure, a plurality of groups of the side wall arc structures are symmetrically arranged at both ends of the spherical shell structure along the longitudinal direction, and the radius r of the spherical shell structure is 1.25 cm-1.5 cm.

[0008] Preferably, the side wall arc structure includes a first side wall arc, a second side wall arc, a third side wall arc and a fourth side wall arc, and multiple groups of the first side wall arc, the second side wall arc, the third side wall arc and the fourth side wall arc are symmetrically arranged at both ends of the spherical shell structure along the longitudinal center.

[0009] Preferably, the first side wall arc is configured to be concave, and a radius R1 of the first side wall arc is 10 cm-12 cm.

[0010] Preferably, the second side wall arc is configured to be outwardly convex, and a radius R2 of the second side wall arc is 10 cm-12 cm.

[0011] Preferably, the third side wall arc is set to be concave, and the radius R3 of the third side wall arc is 5cm-8cm.

[0012] Preferably, the fourth side wall arc is set to be concave, and the radius R4 of the fourth side wall arc is 1.25cm-1.5cm.

[0013] Preferably, bending angles are provided between the plurality of groups of the side wall arc structures, and the angle α of the bending angles is 8.5°-10.5°.

[0014] The preparation process of the variable-section gourd-shaped corrugated pipe is used to prepare the corrugated pipe, and the preparation process includes the following steps:

[0015] S1, prepare raw materials. First, metal materials are collected from the raw material warehouse according to production needs. During the collection process, the material specifications, quantity, type, appearance and performance are tested. After the test is completed, the collected metal materials are cut into metal sheets and the specifications and lengths of the metal sheets are checked.

[0016] S2, preparing a rough mold, rolling the blanked metal sheet to form a circular tubular structure, and longitudinally welding the rolled tube, and annealing after welding;

[0017] S3, rough mold processing, removing the oxide layer on the surface of the tube after annealing by mechanical grinding, and then cleaning and drying;

[0018] S4, preparing a tube blank, sheathing a multi-layer tube on the surface of the dried rough mold, performing ring end welding on the sheathed tube, and performing rounding treatment on the welded tube;

[0019] S5, preparing gourd-shaped corrugations, extruding the rounded tube blank through the cooperation of hydraulic equipment and molds, and then using investment mold technology to shape the side wall arc structure and spherical shell radius structure, and demolding operation is performed after the investment mold treatment is completed;

[0020] S6, prepare the finished product, redistribute the stress inside the material through mechanical vibration of the demoulding tube, thereby releasing it. After the stress is released, clean the tube again and perform trimming to remove burrs. After trimming, the processed gourd-shaped corrugated tube is circulated and stored.

[0021] Preferably, the processing of the investment mold and demoulding includes the following steps:

[0022] S501, prepare the mold, first prepare the mold of the gourd-shaped corrugation of the corrugated pipe;

[0023] S502, selecting an investment pattern material, such as wax and resin investment pattern materials;

[0024] S503, performing mold casting, heating the selected investment mold material to a liquid state, and then pouring it into the mold;

[0025] S504, cooling and solidifying, until the investment material solidifies to form the desired bellows gourd shape;

[0026] S505, demoulding is performed, the mold is heated to the melting point of the investment material to melt it, and after the investment material is completely melted, the mold is opened to discharge the material, and the mold is cleaned after demoulding is completed.

[0027] Technical effects and advantages of the present invention:

[0028] The present invention forms a bellows structure through a plurality of corrugated structures which are arranged in a longitudinal composite stack, wherein the corrugated structure is formed into a gourd shape by a side wall arc structure and a spherical shell radius structure, and by adjusting the radius data of the side wall arc structure and the spherical shell radius structure, the side wall of the waveform is not only strengthened compared with the U-shaped wave, but also the radius of the arc spherical shell can be reduced, thereby improving the pressure resistance of the bellows and increasing the compression ratio of a single wave, and because a variety of composite bellows are used, a plurality of diaphragm shapes of different arcs are flexibly composited and stacked according to a certain rule, thereby improving the pressure resistance, the displacement per unit length and the overall axial stiffness of the bellows. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall structure of the bellows of the present invention.

[0030] Figure 2 It is a schematic structural diagram of the corrugated structure of the present invention.

[0031] Figure 3 The present invention is a process flow chart of the processing of the variable-section gourd-shaped corrugated pipe.

[0032] In the figure: 1, tube body; 2, corrugated structure; 201, spherical shell structure; 202, first side wall arc; 203, second side wall arc; 204, third side wall arc; 205, fourth side wall arc; 206, bending angle. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Embodiment 1, the present invention provides as follows Figure 1 The variable-section gourd-shaped corrugated pipe shown comprises a pipe body 1, wherein a plurality of corrugated structures 2 are compound-stacked and arranged in the middle of the pipe body 1 along the longitudinal direction;

[0035] The corrugated structure 2 is composed of a side wall arc structure and a spherical shell radius structure, and the corrugated structure 2 is formed into a gourd shape by the side wall arc structure and the spherical shell radius structure.

[0036] It should be noted that in the actual setting, according to the use requirements of the bellows, the corrugated structure 2 with side wall arc structures and spherical shell radius structures of different sizes can be compositely superimposed to form it. In this way, multiple diaphragm shapes with different arcs can be flexibly composited and superimposed according to a certain rule, thereby greatly improving its pressure resistance, displacement per unit length and overall axial stiffness of the bellows.

[0037] Specifically, refer to Figure 2 As shown, the spherical shell radius structure includes a spherical shell structure 201, and a plurality of groups of side wall arc structures are symmetrically arranged at both ends of the spherical shell structure 201 along the longitudinal direction. The radius r of the spherical shell structure 201 is 1.25 cm-1.5 cm.

[0038] Specifically, the side wall arc structure includes a first side wall arc 202, a second side wall arc 203, a third side wall arc 204 and a fourth side wall arc 205, and multiple groups of first side wall arcs 202, second side wall arcs 203, third side wall arcs 204 and fourth side wall arcs 205 are symmetrically arranged at both ends of the spherical shell structure 201 along the longitudinal center.

[0039] It should be noted that the spherical shell structure 201, the first side wall arc 202, the second side wall arc 203, the third side wall arc 204 and the fourth side wall arc 205 together form a gourd-shaped structure, which is different from the U-shaped bellows structure, and through different design changes in the radius sizes of the spherical shell structure 201, the first side wall arc 202, the second side wall arc 203, the third side wall arc 204 and the fourth side wall arc 205, the waveform is compared with the U-shaped wave, not only the side wall is strengthened, but also the radius of the arc spherical shell is reduced, thereby improving the pressure resistance of the bellows and increasing the compression ratio of a single wave.

[0040] Furthermore, the first side wall arc 202 is configured to be concave, and a radius R1 of the first side wall arc 202 is 10 cm-12 cm.

[0041] Furthermore, the second side wall arc 203 is configured to be outwardly convex, and a radius R2 of the second side wall arc 203 is 10 cm-12 cm.

[0042] Furthermore, the third side wall arc 204 is configured to be concave, and a radius R3 of the third side wall arc 204 is 5 cm-8 cm.

[0043] Furthermore, the fourth side wall arc 205 is configured to be concave, and a radius R4 of the fourth side wall arc 205 is 1.25 cm-1.5 cm.

[0044] Furthermore, bending angles 206 are provided between the multiple groups of side wall arc structures, and the angle α of the bending angle 206 is 8.5°-10.5°.

[0045] Embodiment 2, the present invention provides as follows Figure 3 The manufacturing process of the variable cross-section gourd-shaped corrugated pipe shown is used to manufacture the corrugated pipe of Example 1, and the manufacturing process includes the following steps:

[0046] S1, prepare raw materials. First, metal materials are collected from the raw material warehouse according to production needs. During the collection process, the material specifications, quantity, type, appearance and performance are tested. After the test is completed, the collected metal materials are cut into metal sheets and the specifications and lengths of the metal sheets are checked.

[0047] It should be noted that the required metal materials should be selected according to the actual use of the metal bellows to be prepared, and the procedures for receiving materials should be standardized. First, the production department shall fill out the material application form to clarify the type, specification and quantity information of the required materials. Then, according to the material application form, go to the warehouse or material storage area to receive the materials, and then check the material specifications to check whether the materials received are consistent with the specifications on the application form (such as thickness, width and length); check the quantity of materials to confirm whether the quantity of materials received is consistent with the application form; check the material type to ensure that the materials received are of the correct material (such as stainless steel, carbon steel, etc.); check the appearance of the material to ensure that there are no obvious defects such as damage, rust, deformation, etc.; verify the identification label of the material to ensure that it meets the relevant standards and requirements; according to the company's quality control requirements, it may be necessary to conduct some basic performance tests on the material (such as hardness, tensile strength, etc.).

[0048] Record the detailed information of the materials received in the material receiving form or inventory management system, including material type, specification, quantity, receiving date, inspection results, etc.

[0049] S2, preparing a rough mold, rolling the blanked metal sheet to form a circular tubular structure, and longitudinally welding the rolled tube, and annealing after welding;

[0050] It should be noted that during the metal sheet rolling process, the raw materials may need to be heat treated to improve their workability and performance, and then the metal sheets are hot rolled into a tube through a rolling machine, and then the rolled tube is longitudinally welded to ensure the integrity and strength of the tube.

[0051] S3, rough mold processing, remove the annealed oxide layer on the surface of the pipe by mechanical grinding, and then clean and dry it to remove surface oil and impurities, and dry the cleaned pipe to ensure that there is no moisture left on the surface;

[0052] It should be noted that the annealing treatment of the pipe also includes heat treatment to relieve stress, that is, heating the pipe to the recrystallization temperature range of the material and maintaining the temperature for a certain period of time to ensure the uniformity of the internal structure of the material, and then slowly cooling to room temperature, usually internal cooling to prevent new stress from being generated on the material surface. This solution adopts a mechanical stress relief method, placing the pipe in a moving device, starting the device, and starting after setting the time. It usually starts with the vibration frequency and time according to the characteristics of the material. Finally, the stress state of the material can be changed by applying a tensile force.

[0053] S4, preparing the tube blank, sheathing multiple layers of tubes on the surface of the rough mold after drying to enhance the performance of the tube, and performing ring end welding on the sheathed tube to ensure that the connection between the layers is firm, and performing rounding treatment on the welded tube to ensure that the shape and size of the tube meet the standards;

[0054] It should be noted that the rounding treatment of the pipe after welding is an important step to ensure that the welded pipe has good geometric shape and dimensional accuracy. The rounding treatment is mainly to repair the deformation and out-of-roundness that may occur during the welding process. The specific operation steps are as follows:

[0055] Preliminary inspection, before the rounding process, the welded pipe is first inspected to evaluate its roundness, straightness and weld quality.

[0056] Choose the rounding equipment. According to the diameter and material of the pipe, choose the appropriate rounding equipment. Common equipment includes rounding machines, rounding machines or pipe drawing machines.

[0057] Clamp the pipes to be processed on the full-circle equipment to ensure that the pipes are firmly fixed during operation.

[0058] Adjust equipment parameters and set rounding equipment parameters such as pressure, speed and feed rate according to the specifications of the pipe to ensure the effectiveness and safety of the rounding process.

[0059] Perform the rounding treatment, start the rounding equipment, and perform the rounding operation on the pipe. The equipment usually applies a certain pressure to restore the pipe to the ideal round state during the process.

[0060] Regular inspection: During the rounding process, the roundness and straightness of the pipe are regularly checked to ensure that they meet the expected standards.

[0061] Post-processing: After the rounding is completed, post-processing can be carried out, such as removing surface oxides, cleaning, etc., to improve the surface quality of the pipe.

[0062] Final inspection: Perform final inspection on the rounded tubes to ensure that their roundness, straightness and other geometric parameters meet relevant standards and design requirements.

[0063] S5, preparing gourd-shaped corrugations, extruding the rounded tube blank through the cooperation of hydraulic equipment and molds, and then using investment mold technology to shape the side wall arc structure and spherical shell radius structure, and demolding operation is performed after the investment mold treatment is completed;

[0064] Specifically, the processing of investment and demoulding includes the following steps:

[0065] S501, prepare the mold, first prepare the mold of the gourd-shaped corrugation of the corrugated pipe;

[0066] S502, selecting an investment pattern material, such as wax and resin investment pattern materials;

[0067] It should be noted that the investment mold is made according to the gourd-shaped corrugation design of the bellows. The investment mold material is usually wax or some resin so that it can be melted smoothly in the subsequent heating process.

[0068] S503, performing mold casting, heating the selected investment mold material to a liquid state, and then pouring it into the mold;

[0069] It should be noted that the investment material is heated to a liquid state and poured into a pre-made mold to form the required gourd-shaped corrugations, and it is ensured that the investment material completely fills every detail of the mold to ensure the accuracy of the final casting.

[0070] S504, cooling and solidifying, until the investment material solidifies to form the desired bellows gourd shape;

[0071] It should be noted that rapid temperature changes should be avoided during this process to prevent cracks.

[0072] S505, demoulding is performed, the mold is heated to the melting point of the investment material to melt it, and after the investment material is completely melted, the mold is opened to discharge the material, and the mold is cleaned after demoulding is completed.

[0073] It should be noted that the surface of the investment pattern needs to be processed, such as polishing and cleaning, to ensure a smooth surface and reduce defects during casting. Before demolding, the mold needs to be heated so that the investment pattern material can melt and flow out smoothly. The heating temperature must be the melting point of the investment pattern material.

[0074] S6, prepare the finished product, redistribute the stress inside the material through mechanical vibration of the demoulding tube, thereby releasing it. After the stress is released, clean the tube again and perform trimming to remove burrs. After trimming, the processed gourd-shaped corrugated tube is circulated and stored.

[0075] It should be noted that after the gourd-shaped corrugated pipe is prepared, size and waveform inspection is an important step to ensure product quality. The specific operation steps are as follows:

[0076] Preparation work, tools and equipment preparation, including dimensional measuring tools, calipers, micrometers, measuring pads and steel tape measures; waveform inspection tools, corrugation measuring instruments, templates or samples; recording tools, paper and pen or electronic equipment, used to record measurement data. Sample preparation, ensure that the surface of the corrugated pipe to be inspected is clean, free of oil and debris, so as not to affect the measurement results.

[0077] Dimension inspection, including outer diameter measurement, use calipers or micrometers to measure the outer diameter of the bellows, select different positions (such as crests, troughs, etc.) for multi-point measurement, and record the data; inner diameter measurement, use inner diameter measuring tools (such as inner diameter micrometers) to measure the inner diameter of the bellows, also measure and record at different positions; wall thickness measurement, measure the wall thickness at the crests and troughs of the pipe, and ensure multi-point measurement to obtain an accurate average value; length and straightness inspection, use a steel tape measure to measure the total length of the bellows, check the straightness of the pipe, and ensure that it meets the design requirements.

[0078] Waveform inspection, including waveform appearance inspection, visual inspection of the waveform of the bellows to ensure that the corrugation is uniform and has no obvious defects (such as twisting, dents, etc.); use a corrugation measuring instrument to record parameters such as the height, width and spacing of the corrugation; template comparison method; use a pre-made corrugation template, place the bellows on the template, check the matching of the corrugation, and evaluate the accuracy of the waveform.

[0079] Recording and analysis, including data recording, recording all measurement results in detail, including measurement location, measurement value and allowable tolerance; data analysis, comparing the measurement data with the design standards, analyzing whether it meets the technical requirements and judging whether it is qualified; defect handling, if the size or waveform is found to be unqualified, the defect type and location must be recorded, and rectification or rework must be carried out.

[0080] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Variable cross-section gourd-shaped corrugated pipe, characterized in that: It comprises a tube body (1), wherein a plurality of corrugated structures (2) are compositely stacked and arranged in the middle of the tube body (1) along the longitudinal direction; The corrugated structure (2) is composed of a side wall arc structure and a spherical shell radius structure, and the corrugated structure (2) is formed into a gourd shape by the side wall arc structure and the spherical shell radius structure.

2. The variable cross-section gourd-shaped corrugated pipe according to claim 1, characterized in that: The spherical shell radius structure comprises a spherical shell structure (201), and a plurality of groups of side wall arc structures are symmetrically arranged at two ends of the spherical shell structure (201) along the longitudinal direction. The radius r of the spherical shell structure (201) is 1.25 cm to 1.5 cm.

3. The variable cross-section gourd-shaped corrugated pipe according to claim 2, characterized in that: The side wall arc structure comprises a first side wall arc (202), a second side wall arc (203), a third side wall arc (204) and a fourth side wall arc (205); a plurality of groups of the first side wall arc (202), the second side wall arc (203), the third side wall arc (204) and the fourth side wall arc (205) are sequentially arranged at two ends of the spherical shell structure (201) in a longitudinally centrally symmetrical manner.

4. The variable cross-section gourd-shaped corrugated pipe according to claim 3, characterized in that: The first side wall arc (202) is configured to be concave, and a radius R1 of the first side wall arc (202) is 10 cm to 12 cm.

5. The variable cross-section gourd-shaped corrugated pipe according to claim 3, characterized in that: The second side wall arc (203) is configured to be outwardly convex, and a radius R2 of the second side wall arc (203) is 10 cm to 12 cm.

6. The variable cross-section gourd-shaped corrugated pipe according to claim 3, characterized in that: The third side wall arc (204) is configured to be concave, and the radius R3 of the third side wall arc (204) is 5 cm to 8 cm.

7. The variable cross-section gourd-shaped corrugated pipe according to claim 3, characterized in that: The fourth side wall arc (205) is configured to be concave, and the radius R4 of the fourth side wall arc (205) is 1.25 cm to 1.5 cm.

8. The variable cross-section gourd-shaped corrugated pipe according to claim 2, characterized in that: Bending angles (206) are arranged between the plurality of groups of the side wall arc structures, and the angle α of the bending angles (206) is 8.5°-10.5°.

9. A process for preparing a gourd-shaped corrugated pipe with a variable cross-section, used for preparing the corrugated pipe according to any one of claims 1 to 8, characterized in that: The preparation process comprises the following steps: S1, prepare raw materials. First, metal materials are collected from the raw material warehouse according to production needs. During the collection process, the material specifications, quantity, type, appearance and performance are tested. After the test is completed, the collected metal materials are cut into metal sheets and the specifications and lengths of the metal sheets are checked. S2, preparing a rough mold, rolling the blanked metal sheet to form a circular tubular structure, and longitudinally welding the rolled tube, and annealing after welding; S3, rough mold processing, removing the oxide layer on the surface of the tube after annealing by mechanical grinding, and then cleaning and drying; S4, preparing a tube blank, sheathing a multi-layer tube on the surface of the dried rough mold, performing ring end welding on the sheathed tube, and performing rounding treatment on the welded tube; S5, preparing gourd-shaped corrugations, extruding the rounded tube blank through the cooperation of hydraulic equipment and molds, and then using investment mold technology to shape the side wall arc structure and spherical shell radius structure, and demolding operation is performed after the investment mold treatment is completed; S6, prepare the finished product, redistribute the stress inside the material through mechanical vibration of the demoulding tube, thereby releasing it. After the stress is released, clean the tube again and perform trimming to remove burrs. After trimming, the processed gourd-shaped corrugated tube is circulated and stored.

10. The process for preparing the variable cross-section gourd-shaped corrugated pipe according to claim 9, characterized in that: The processing of the investment mold and demoulding includes the following steps: S501, prepare the mold, first prepare the mold of the gourd-shaped corrugation of the corrugated pipe; S502, selecting the investment pattern material, and selecting the investment pattern material of wax and resin; S503, performing mold casting, heating the selected investment mold material to a liquid state, and then pouring it into the mold; S504, cooling and solidifying, until the investment material solidifies to form the desired bellows gourd shape; S505, demoulding is performed, the mold is heated to the melting point of the investment material to melt it, and after the investment material is completely melted, the mold is opened to discharge the material, and the mold is cleaned after demoulding is completed.

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