Apparatus for welding bushings and liners to flanges and their usage methods

Abstract

This application discloses an apparatus and method for welding a bushing and a sleeve to a flange. The apparatus includes: a clamping fixture comprising: a U-shaped bending rod having a shorter end and a longer end; a top liner disposed at the shorter end of the bending rod; first and second bottom pressure plates disposed at the longer end of the bending rod; diagonal tie rods disposed between the first and second bottom pressure plates; and multiple nuts disposed below the first and second bottom pressure plates; and a support fixture comprising: a central tube assembly located at the center of the sleeve; multiple ring plates with gaps between them; and multiple connecting pipes, one end of which is welded to the central tube assembly and the other end of which abuts against the inner side of the corresponding ring plate via a support rod. This apparatus and method ensure the welding quality of the bushing and sleeve structure and reduce the risk of leakage during flange use.

Description

Technical Field

[0001] This application generally relates to the technical field of manufacturing pressure vessels, and more particularly to an apparatus for welding a bushing and a liner to a flange and a method of using the same. Background Technology

[0002] In the coal chemical and petrochemical equipment industries, there is often a need for equipment with small diameters but requiring corrosion resistance internally. To save costs, the flanges are designed as forgings of carbon steel or low-alloy materials, and the cylinder is made of stainless steel or composite plate. After welding the flange and cylinder, the flange sealing surface consists of a 5-7mm thick stainless steel bushing, and the inner wall is lined with a 4mm thick stainless steel sleeve. This structure often results in poor sealing and leakage due to loose fit between the bushing / sleeve and the flange sealing surface and the inner wall. Furthermore, uneven welds between the sleeve and the inner wall cause localized stress, leading to corrosion cracking. Improper welding sequence can also reduce the corrosion-resistant thickness of the welds at both ends of the inner wall and sleeve, thus shortening the equipment's service life. Therefore, a new type of device is needed that can ensure the overall welding quality of flange components with bushings and sleeves. Summary of the Invention

[0003] In view of the above-mentioned technical problems, this disclosure proposes an apparatus for welding a bushing and a sleeve to a flange, characterized in that it includes: a clamping fixture, the clamping fixture comprising: a bending rod, the bending rod having a U-shaped structure and having a shorter end and a longer end, the longer end also having threads; a top liner plate disposed at the shorter end of the bending rod; a first bottom pressure plate and a second bottom pressure plate disposed at the longer end of the bending rod; and diagonal braces disposed at the first bottom pressure plate and... Between the second bottom pressure plates, for connecting the first bottom pressure plate and the second bottom pressure plate together; and a plurality of nuts, the plurality of nuts being respectively disposed below the first bottom pressure plate and the second bottom pressure plate, for engaging with the thread of the bending rod to fasten the bushing and the flange; and a support fixture, the support fixture comprising: a central tube assembly, the central tube assembly being located at the center of the bushing; a plurality of ring plates, the ring plates having gaps between them; and a plurality of connecting pipes, one end of the connecting pipe being welded to the central tube assembly and the other end of the connecting pipe abutting against the inner side of the corresponding ring plate via a support rod.

[0004] In a preferred embodiment, the gap ranges from 10 mm to 15 mm.

[0005] In a preferred embodiment, the diameter of the bending rod is 20 mm.

[0006] In a preferred embodiment, the number of the plurality of ring plates and the plurality of connecting pipes is three, and the three connecting pipes are at a 120-degree angle to each other.

[0007] This disclosure also proposes a method using the above-described apparatus, characterized in that the method includes the following steps: S1, placing the bushing on the upper surface of the flange such that the inner circle of the bushing is aligned with the inner circle of the flange, and then pressing the bushing and the flange together by tightening the nut of the clamping fixture; S2, welding the outer side of the bushing using a welding rod, and then welding the inner side of the bushing; S3, removing the clamping fixture after welding, and then grinding the inner weld between the bushing and the flange with a grinding wheel until it is flush with the periphery; S4, placing the bushing... The support fixture is placed inside the flange so that the upper surface of the bushing is flush with the lower surface of the bushing ring. The support fixture is placed inside the bushing ring at a certain distance from the upper surface of the bushing ring, and then the bushing ring is pressed against the flange by the support fixture. S5, the bushing ring and the bushing ring are welded by manual tungsten inert gas welding. S6, the support fixture is placed inside the bushing ring at a certain distance from the lower surface of the bushing ring, and then the bushing ring is pressed against the flange by the support fixture. S7, the bushing ring and the cylinder are welded by manual tungsten inert gas welding.

[0008] In a preferred embodiment, the welding electrode in S2 is a dissimilar steel fine welding electrode with a diameter of 3.2 mm.

[0009] In a preferred embodiment, the specified distance is 10 mm.

[0010] In a preferred embodiment, the weld leg height welded on the outer side of the bushing in S2 is not less than 6 mm.

[0011] In a preferred embodiment, the weld leg height in S5 is 4 mm.

[0012] In a preferred embodiment, stainless steel welding wire is used for welding in step S5.

[0013] Compared with the prior art, the beneficial effects of this disclosure are as follows: it ensures a tight fit between the bushing and the flange surface, preventing leakage due to poor sealing; it ensures a tight fit between the inner wall and the inner wall of the flange and cylinder, preventing excessive gaps that could lead to fatigue cracking at both ends of the bushing due to thermal stress during assembly, welding, and equipment operation; and it ensures that the corrosion resistance thickness of the welds at both ends of the bushing and the inner wall meets the design requirements, avoiding a reduction in corrosion resistance thickness and ensuring the service life of the components. Attached Figure Description

[0014] The novel features of this application are specifically set forth in the appended claims. A better understanding of the features and advantages of this application will be gained by referring to the following detailed description and accompanying drawings, which illustrate illustrative embodiments in which the principles of this application are utilized. The drawings are for illustrative purposes only and should not be considered as limiting the scope of this application. Furthermore, the same reference numerals denote the same elements throughout the drawings, in which:

[0015] Figure 1 A schematic diagram of a bushing, a liner, and a flange according to an exemplary embodiment of the present disclosure is shown;

[0016] Figure 2 A schematic diagram of a clamping fixture for welding a bushing and a sleeve to a flange, according to an exemplary embodiment of the present disclosure, is shown.

[0017] Figure 3 A schematic diagram of a support fixture for welding a bushing and a sleeve to a flange, according to an exemplary embodiment of this disclosure, is shown; and

[0018] Figure 4 A flowchart is shown of a method using an apparatus according to an exemplary embodiment of the present disclosure.

[0019] Explanation of reference numerals in the attached drawings: 1-1, flange; 1-2, cylinder; 1-3, liner ring; 1-4, liner; 2-1, diagonal tie rod; 2-2, first bottom pressure plate; 2-3, nut; 2-4, second bottom pressure plate; 2-5, bending rod; 2-6, top liner plate; 3-1, central tube assembly; 3-2, connecting pipe; 3-3, lead screw assembly; 3-4, support rod; 3-5, ring plate. Detailed Implementation

[0020] Exemplary embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of this disclosure and to fully convey the scope of this disclosure to those skilled in the art. Nothing in the following detailed description is intended to suggest that any particular component, feature, or step is essential to this application. Those skilled in the art will understand that various features or steps may be substituted for or combined with each other without departing from the scope of this disclosure.

[0021] Figure 1A schematic diagram of a bushing 1-3, a sleeve 1-4, and a flange 1-1 according to an exemplary embodiment of the present disclosure is shown. In one embodiment, the present disclosure provides an apparatus for welding the bushing and sleeve to a flange, the apparatus including: a clamping fixture and a supporting fixture. Figure 2 A schematic diagram of a clamping fixture for welding a bushing 1-3 and a sleeve 1-4 to a flange 1-1 according to an exemplary embodiment of the present disclosure is shown. In a preferred embodiment, the apparatus according to an exemplary embodiment of the present disclosure may include a plurality of clamping fixtures. The clamping fixture may include: a bending rod 2-5, which has a U-shaped structure and a shorter end and a longer end, the longer end of which is threaded; a top liner 2-6, which may be disposed at the shorter end of the bending rod 2-5; a first bottom pressure plate 2-2 and a second bottom pressure plate 2-4, which may be disposed at the longer end of the bending rod 2-5; a diagonal tie rod 2-1, which may be disposed between the first bottom pressure plate 2-2 and the second bottom pressure plate 2-4 to connect the first bottom pressure plate 2-2 and the second bottom pressure plate 2-4 together; and a plurality of nuts 2-3, which may be disposed below the first bottom pressure plate 2-2 and the second bottom pressure plate 2-4 respectively, for engaging with the threads of the bending rod 2-5 to fasten the bushing 1-3 and the flange 1-1. In a preferred embodiment, the diameter of the bending rod 2-5 can be 20mm.

[0022] Figure 3A schematic diagram of a support fixture for welding a bushing and a sleeve to a flange according to an exemplary embodiment of the present disclosure is shown. In one embodiment, the support fixture may include: a central tube assembly 3-1, which may be located at the center of the sleeve 1-4; a plurality of ring plates 3-5, which may have gaps between them; and a plurality of connecting pipes 3-2, one end of which may be welded to the central tube assembly 3-1 and the other end of which may be abutted against the inner side of a corresponding ring plate 3-5 by a support rod 3-4. In a preferred embodiment, the gap between the ring plates 3-5 may be in the range of 10 mm to 15 mm. In other embodiments, the gap between the ring plates 3-5 may be 5 mm to 10 mm, 5 mm to 20 mm, 5 mm to 25 mm, 10 mm to 15 mm, 10 mm to 20 mm, 10 mm to 25 mm, 15 mm to 20 mm, 15 mm to 25 mm, or any range that a person skilled in the art would consider appropriate. In a preferred embodiment, the number of the plurality of ring plates 3-5 and the plurality of connecting pipes 3-2 are both three, and the three connecting pipes 3-2 are at a 120-degree angle to each other. In a preferred embodiment, the support fixture may further include a lead screw assembly 3-3. Specifically, the center pipe assembly 3-1 and the connecting pipes 3-2 can be connected by threads of the lead screw assembly 3-3. For example, in use, the outer diameter of the support fixture can be reduced first, and then after the support fixture is placed in the designated position, the outer diameter of the support fixture can be increased by rotating the lead screw assembly 3-3 and the connecting pipes 3-2 in sequence to tighten the bushing 1-4 until the gaps between the plurality of ring plates 3-5 are substantially eliminated. Welding operation is then performed after the gaps are substantially eliminated.

[0023] Figure 4 A flowchart of a method using an apparatus according to an exemplary embodiment of the present disclosure is shown. In one embodiment, the present disclosure also proposes a method using the above-described apparatus, which may include S1-S7. Specifically, the method may include S1. In S1, a bushing 1-3 may be placed on the upper surface of the flange 1-1 such that the inner circle of the bushing 1-3 is aligned with the inner circle of the flange 1-1, and then the bushing 1-3 and the flange 1-1 are pressed together by tightening the nut 2-3 of the clamping fixture. A plurality of clamping fixtures may be used to press the bushing 1-3 and the flange 1-1 together, wherein the plurality of clamping fixtures may be circumferentially and evenly arranged on the bushing 1-3 and the flange 1-1. The number of the plurality of clamping fixtures is preferably 6. The method may further include S2. In S2, welding may be performed on the outer side of the bushing 1-3 using a welding rod (as shown in the figure). Figure 1 Welding is performed at position ① shown in the diagram), and then welding is performed on the inner side of the bushings 1-3 (as shown in the diagram). Figure 1(Welding is performed at position ② in the diagram). In a preferred embodiment, the welding rod is a dissimilar steel fine welding rod with a diameter of 3.2 mm. In other embodiments, the welding rod can be any type of welding rod deemed appropriate by those skilled in the art. In a preferred embodiment, the weld leg height welded on the outer side of the bushing 1-3 is not less than 6 mm. In other embodiments, the weld leg height welded on the outer side of the bushing 1-3 can be not less than 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or any height deemed appropriate by those skilled in the art. The method may also include S3. In S3, after welding is completed, the clamping fixture can be removed, and then a grinding wheel can be used to grind the inner weld between the bushing 1-3 and the flange 1-1 until it is flush with the periphery. The method may also include S4. In S4, the liner 1-4 can be placed inside the flange 1-1, such that the upper surface of the liner 1-4 is flush with the lower surface of the bushing 1-3. The support fixture is placed inside the liner 1-4 at a certain distance from its upper surface, and then the liner 1-4 is tightened against the flange 1-1 using the support fixture. In a preferred embodiment, the certain distance can be 10 mm. In other embodiments, the certain distance can be 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, or any distance deemed appropriate by those skilled in the art. The method may also include S5. In S5, the liner 1-4 and the bushing 1-3 can be welded by manual tungsten inert gas welding (as in...). Figure 1 (Welding is performed at position ③ in the diagram). In other embodiments, the liner 1-4 and the ring 1-3 can be welded by any welding method deemed appropriate by those skilled in the art. The weld leg height can be 4 mm. In other embodiments, the weld leg height can be 3 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, or any height deemed appropriate by those skilled in the art. In a preferred embodiment, stainless steel welding wire can be used for welding in S5. The method may also include S6. In S6, the support fixture can be placed inside the liner 1-4 and at a certain distance from the lower surface of the liner 1-4, and then the liner 1-4 is tightened against the flange 1-1 by the support fixture. The method may also include S7. In S7, the liner 1-4 and the cylinder 1-2 can be welded by manual tungsten inert gas welding (as shown in the diagram). Figure 1 (Welding is performed at position ④ shown in the diagram). In other embodiments, the liner 1-4 and the cylinder 1-2 can be welded by any welding method deemed appropriate by those skilled in the art.

[0024] Compared with the prior art, the technical solution of this disclosure ensures a tight fit between the stainless steel bushing and the sealing surface of the carbon steel flange, while also ensuring a tight fit between the stainless steel bushing and the flange and the inner wall of the bushing. Ultimately, this ensures the welding quality of the bushing and bushing structure and greatly reduces the risk of leakage during the use of the flange component.

[0025] It should be understood that the systems and / or methods provided in the various embodiments of this invention can be combined, modified, and / or altered to form new technical solutions. Without inventive effort, these technical solutions should also be included within the scope of protection claimed by this invention.

[0026] Numerous specific examples are provided in the embodiments described herein, and it should be understood that these examples are merely for illustrating the embodiments of the invention in detail and are not intended to limit the invention. Embodiments of the invention can be practiced without these specific examples. In some embodiments, methods, structures, and / or techniques well-known to those skilled in the art are not shown in detail so as not to obscure the understanding of the invention.

[0027] While preferred embodiments of the invention have been shown and described herein, it will be readily understood by those skilled in the art that these embodiments are provided by way of example only. Various changes, modifications, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein are optionally used to practice the invention. The scope of the invention is intended to be defined by the claims, and thereby covers the methods and structures within the scope of these claims and their equivalents.

Claims

1. An apparatus for welding a bushing and a sleeve to a flange, characterized in that, include: The clamping fixture includes: A bent bar, the bent bar having a U-shaped structure and having a shorter end and a longer end, the longer end also having a thread; A top liner, wherein the top liner is disposed at the shorter end of the bent rod; A first bottom pressure plate and a second bottom pressure plate are disposed at the longer end of the bending rod. A diagonal brace, wherein the diagonal brace is disposed between the first bottom pressure plate and the second bottom pressure plate, for connecting the first bottom pressure plate and the second bottom pressure plate together; and Multiple nuts, respectively disposed below the first and second bottom pressure plates, are used to engage with the threads of the bent rod to fasten the bushing and the flange; and Support fixture, the support fixture includes: A central tube assembly, wherein the central tube assembly is located at the center of the liner; Multiple ring plates, wherein the ring plates have gaps between them; Multiple connecting pipes, one end of which is welded to the central pipe assembly, and the other end of which abuts against the inner side of the corresponding ring plate via a support rod.

2. The apparatus according to claim 1, characterized in that, The gap ranges from 10 mm to 15 mm.

3. The apparatus according to claim 1, characterized in that, The diameter of the bent rod is 20mm.

4. The apparatus according to claim 1, characterized in that, The number of the plurality of ring plates and the plurality of connecting pipes are all three, and the three connecting pipes are at a 120-degree angle to each other.

5. A method of using the apparatus according to any one of claims 1-4, characterized in that, The method includes the following steps: S1, place the bushing on the upper surface of the flange so that the inner circle of the bushing is aligned with the inner circle of the flange, and then tighten the bushing and the flange by tightening the nut of the clamping fixture; S2, Welding is performed on the outside of the bushing using welding rods, and then welding is performed on the inside of the bushing; S3. After welding is completed, remove the clamping fixture, and then use a grinding wheel to grind the inner weld of the bushing and the flange until it is flush with the periphery. S4, place the liner inside the flange so that the upper surface of the liner is flush with the lower surface of the bushing, place the support fixture inside the liner at a certain distance from the upper surface of the liner, and then use the support fixture to press the liner against the flange tightly. S5, the liner and the bushing are welded by manual tungsten inert gas welding; S6, the support fixture is placed inside the liner at a certain distance from the lower surface of the liner, and then the liner is tightened against the flange using the support fixture; and S7, the liner and cylinder are welded by manual tungsten inert gas welding.

6. The method according to claim 5, characterized in that, The specified distance is 10mm.

7. The method according to claim 5, characterized in that, In S2, the weld leg height welded on the outer side of the bushing shall not be less than 6 mm.

8. The method according to claim 5, characterized in that, The weld leg height described in S5 is 4mm.

9. The method according to claim 5, characterized in that, S5 uses stainless steel welding wire of the same type for welding.

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