Seamless welding machine and welding method for PFA (Polyfluoroalkoxy) pipe

Abstract

The invention belongs to the technical field of PFA pipe welding equipment, and particularly relates to a seamless PFA pipe welding machine and a welding method. The seamless welding machine for the PFA pipe comprises a heating sleeve used for covering the periphery of a to-be-welded part of a pipe fitting and heating the to-be-welded part; the radial pressurizing device is used for being arranged on the inner side of the to-be-welded part of the pipe fitting and applying radial pressure to the inner wall of the to-be-welded part during welding; and the two pipe fitting axial moving mechanisms are used for clamping the two pipe fittings and applying axial pressure to the to-be-welded part during welding. The heating sleeve is arranged on the periphery of the to-be-welded part of the pipe fitting, on one hand, the to-be-welded part can be heated to the welding temperature, on the other hand, radial deformation of the to-be-welded part can be restrained, and seamless welding of the pipe fitting can be achieved in cooperation with the radial pressurizing device and the pipe fitting axial moving mechanism which are arranged on the inner side of the to-be-welded part; the welded inner wall of the welded pipe is free of craters, and the flow velocity and flow of gas or liquid are not affected.

Description

Technical Field

[0001] The present invention belongs to the technical field of PFA pipe welding equipment, and particularly relates to a seamless welding machine for PFA pipes and a welding method. Background Art

[0002] Due to its excellent corrosion resistance, high purity, and high temperature resistance, PFA pipes are widely used in high-purity fluid transportation systems. Currently, the welding of PFA pipes mainly adopts hot air welding or butt welding technology, but the existing technology has the following problems:

[0003] 1. Unstable welding quality: Bubbles, cracks, or impurities are easily generated during the welding process, affecting the sealing performance and strength of the weld.

[0004] 2. There are welding scars at the inner wall welding part of the PFA pipe, affecting the flow rate or velocity of gas or liquid;

[0005] 3. Uneven welding pressure: It is difficult for external fixtures to achieve uniform pressure distribution, resulting in unstable welding quality;

[0006] 4. Complicated operation: Frequent adjustment of fixtures is required, increasing the operation difficulty and time cost. Summary of the Invention

[0007] The purpose of the present invention is to provide a seamless welding machine for PFA pipes and a welding method.

[0008] The present application provides a seamless welding machine for PFA pipes. The seamless welding machine for PFA pipes includes:

[0009] A heating sleeve for covering the outer periphery of the welding part of the pipe fitting to heat the welding part;

[0010] A radial pressurizing device for being arranged inside the welding part of the pipe fitting to apply radial pressure to the inner wall of the welding part during welding; and

[0011] Two pipe fitting axial movement mechanisms for clamping two pipe fittings and applying axial pressure to the welding part during welding.

[0012] In an embodiment of the present application, the seamless welding machine for PFA pipes further includes:

[0013] A base;

[0014] A heating sleeve opening and closing assembly arranged on the base for driving the heating sleeve to open or close.

[0015] In an embodiment of the present application, the heating sleeve opening and closing assembly includes:

[0016] A lower mounting seat fixed on the base and having a lower mounting groove provided at its top;

[0017] The upper mounting seat, one end of which is hinged to one side of the lower mounting groove of the lower mounting seat, and the bottom surface of the upper mounting seat is provided with an upper mounting groove adapted to the lower mounting groove;

[0018] The heating sleeve includes a lower heating sleeve and an upper heating sleeve respectively disposed in the lower mounting groove and the upper mounting groove; wherein

[0019] When the upper mounting seat and the lower mounting seat are closed, the upper heating sleeve and the lower heating sleeve are closed to form the heating sleeve.

[0020] In an embodiment of the present application, both the upper heating sleeve and the lower heating sleeve include:

[0021] A heating tube;

[0022] A heating element mounting block disposed on the outer wall of the middle part of the heating tube; a heating element is disposed in the heating element mounting block; and

[0023] A mounting block disposed at the end of the heating tube for mounting in the corresponding mounting groove.

[0024] In an embodiment of the present application, the radial pressing device includes:

[0025] An airbag, and a connector for connecting an air nozzle is disposed on the inner side of the front end thereof;

[0026] A front cover and a rear cover respectively disposed on the outer peripheries of both ends of the airbag; and

[0027] An axial tensioning assembly disposed inside the airbag for tensioning both ends of the airbag.

[0028] In an embodiment of the present application, the axial tensioning assembly includes:

[0029] A tensioning member;

[0030] A fixing ring connected to the front end of the tensioning member for fixing to the inner side of the connector; and

[0031] A fixing column connected to the rear end of the tensioning member for fixing to the rear cover.

[0032] In an embodiment of the present application, two parallel guide rods are disposed on the base;

[0033] The pipe fitting axial movement mechanism includes:

[0034] A moving seat, both ends of which are respectively sleeved on the corresponding guide rods;

[0035] A pipe fitting clamping assembly mounted on the moving seat; and

[0036] A moving seat driving assembly for driving the moving seat to move towards or away from the heating sleeve.

[0037] In an embodiment of the present application, the moving seat driving assembly includes:

[0038] A motor base fixed at both ends on corresponding guide rods;

[0039] A driving motor fixed on the motor base; and

[0040] A lead screw, one end of which is connected to the output shaft of the driving motor and the other end of which is in threaded cooperation with the moving seat.

[0041] In an embodiment of the present application, a cooling device is provided on one side of the heating sleeve on the base.

[0042] Correspondingly, the present application provides a method for seamless welding of PFA tubes, including:

[0043] Centering the welding ends of two pipe fittings and clamping them in the heating sleeve;

[0044] Placing the radial pressing device on the welding portion of the pipe fitting and applying a preset radial pressure to the welding portion through the radial pressing device;

[0045] Heating the welding portion through the heating sleeve;

[0046] Driving the two pipe fittings to move towards each other by a preset distance simultaneously through two pipe fitting axial movement mechanisms so as to apply an axial pressure to the welding portion during welding.

[0047] The beneficial effects of the present invention are:

[0048] Different from the prior art, the present application provides a seamless welding machine for PFA tubes. The seamless welding machine for PFA tubes includes: a heating sleeve for covering the outer periphery of the welding portion of the pipe fitting to heat the welding portion; a radial pressing device for being arranged inside the welding portion of the pipe fitting to apply a radial pressure to the inner wall of the welding portion during welding; and two pipe fitting axial movement mechanisms for clamping two pipe fittings to apply an axial pressure to the welding portion during welding. By arranging a heating sleeve on the outer periphery of the welding portion of the pipe fitting, on the one hand, the welding portion can be heated to the welding temperature, and on the other hand, the radial deformation of the welding portion can be restricted. Cooperating with the radial pressing device and the pipe fitting axial movement mechanism arranged inside the welding portion, seamless welding of the pipe fitting can be achieved, there is no weld scar at the welding joint of the inner wall of the welded pipe, and it has no influence on the flow rate and flow of gas or liquid.

[0049] Other features and advantages of the present invention will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention. The objectives and other advantages of the present invention are achieved and obtained by the structures specifically pointed out in the specification and the drawings.

[0050] To make the above objects, features, and advantages of the present invention more apparent and understandable, the following provides preferred embodiments in conjunction with the accompanying drawings and detailed descriptions are as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0052] Figure 1 is a perspective view of a PFA tube seamless welding machine according to a preferred embodiment of the present invention;

[0053] Figure 2 is a schematic diagram of the cooperation between a heating sleeve and a radial pressing device according to a preferred embodiment of the present invention;

[0054] Figure 3 is a schematic diagram of a heating sleeve opening and closing assembly according to a preferred embodiment of the present invention;

[0055] Figure 4 is a schematic diagram of a heating sleeve according to a preferred embodiment of the present invention;

[0056] Figure 5 is a schematic diagram of a radial pressing device according to a preferred embodiment of the present invention;

[0057] Figure 6 is a cross-sectional view of a radial pressing device according to a preferred embodiment of the present invention;

[0058] Figure 7 is a schematic diagram of an axial tensioning assembly of a radial pressing device according to a preferred embodiment of the present invention;

[0059] Figure 8 is a schematic diagram of a pipe fitting axial movement mechanism according to a preferred embodiment of the present invention.

[0060] In the figure:

[0061] Pipe fitting 100, heating sleeve 1, lower heating sleeve 11, upper heating sleeve 12, heating pipe 13, heating element mounting block 131, heating element 132, mounting block 133, radial pressure applying device 2, airbag 21, air nozzle 22, joint 23, front cover 24, rear cover 25, axial tensioning assembly 26, tensioning member 261, fixing ring 262, fixing column 263, pipe fitting axial movement mechanism 3, moving seat 31, pipe fitting clamping assembly 32, moving seat drive assembly 33, motor seat 331, drive motor 332, lead screw 333, base 4, heating sleeve opening and closing assembly 5, lower mounting seat 51, lower mounting groove 511, upper mounting seat 52, upper mounting groove 521, guide rod 6, cooling device 7. Detailed implementation manners

[0062] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0063] This application provides a PFA pipe seamless welding machine and a welding method, which will be described in detail below. It should be noted that the description order of the following embodiments does not limit the preferred order of the embodiments of this application. And in the following embodiments, each embodiment has its own emphasis. For parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0064] See Figure 1 and Figure 2 In an embodiment, the PFA pipe seamless welding machine includes: a heating sleeve 1 for covering the outer periphery of the welding portion of the pipe fitting 100 to heat the welding portion; a radial pressure applying device 2 for being disposed inside the welding portion of the pipe fitting 100 to apply a radial pressure to the inner wall of the welding portion during welding; and two pipe fitting axial movement mechanisms 3 for clamping two pipe fittings 100 to apply an axial pressure to the welding portion during welding.

[0065] In this embodiment, when preparing for welding, the welding ends of the two pipe fittings can be aligned and fixed inside the heating sleeve 1; then the radial pressure applying device 2 is placed inside the welding end of the pipe fitting, that is, inside the welding portion; finally, the two pipe fitting axial movement mechanisms 3 clamp the two pipe fittings respectively. During welding, the radial pressure applying device 2 first applies a preset radial pressure to the inner wall of the welding portion, and the heating sleeve 1 heats the welding portion. When the welding temperature is reached, the two pipe fitting axial movement mechanisms 3 drive the two pipe fittings 100 to move towards each other to compensate for the shrinkage length of the pipe fittings after heating and generate a certain axial pressure.

[0066] See Figure 1 and Figure 3 The PFA tube seamless welding machine further includes: a base 4; a heating sleeve opening and closing assembly 5 provided on the base 4 for driving the heating sleeve 1 to open or close.

[0067] Specifically, the heating sleeve opening and closing assembly 5 includes: a lower mounting seat 51 fixed on the base 4 and having a lower mounting groove 511 provided at its top; an upper mounting seat 52, one end of which is hinged to one side of the lower mounting groove 511 of the lower mounting seat 51, and an upper mounting groove 521 adapted to the lower mounting groove 511 is provided on the bottom surface of the upper mounting seat 52; the heating sleeve 1 includes a lower heating sleeve 11 and an upper heating sleeve 12 respectively disposed in the lower mounting groove 511 and the upper mounting groove 521; when the upper mounting seat 52 and the lower mounting seat 51 are closed, the upper heating sleeve 12 and the lower heating sleeve 11 are closed to form the heating sleeve 1.

[0068] In this embodiment, optionally, the upper mounting seat 52 can be opened or closed around the hinge point, so that it is convenient to put the pipe fitting into the heating sleeve 1 or take it out. After the upper mounting seat 52 and the lower mounting seat 51 are closed, the upper mounting seat 52 can be fastened to the lower mounting seat 51 by fixing parts or fixing pins, so as to clamp and fix the part to be welded.

[0069] See Figure 3 and Figure 4 Optionally, both the upper heating sleeve 12 and the lower heating sleeve 11 include: a heating tube 13; a heating element mounting block 131 provided on the outer wall of the middle part of the heating tube 13; a heating element 132 is provided in the heating element mounting block 131; and a mounting block 133 provided at the end of the heating tube 13 for mounting in the corresponding mounting groove.

[0070] In this embodiment, the heating element 132 can be a heating rod, which is arranged on the outer periphery of the middle part of the heating sleeve 1 and can uniformly heat the part to be welded.

[0071] See Figure 2 , Figure 5 and Figure 6 Preferably, the radial pressing device 2 includes: an airbag 21, and a joint 23 for connecting a nozzle 22 is provided on the inner side of the front end thereof; a front cover 24 and a rear cover 25 are respectively provided on the outer peripheries of both ends of the airbag 21; and an axial tensioning assembly 26 is provided inside the airbag 21 for tensioning both ends of the airbag 21.

[0072] In this embodiment, the nozzle 22 can be connected to the trachea of an external air source, and an air passage connecting the nozzle 22 and the airbag 21 is provided inside the joint 23. The airbag 21 can be inflated through the nozzle 22, and after the airbag 21 expands, a radial pressure can be generated on the inner wall of the part to be welded. The axial tensioning assembly 26 can prevent the axial expansion of the airbag 21, thereby avoiding the problem of insufficient radial pressure generated by the airbag 21 on the inner wall of the part to be welded due to axial expansion.

[0073] Optionally, referring to Figure 6 and Figure 7 , the axial tensioning assembly 26 includes: a tensioning member 261; a fixing ring 262 connected to the front end of the tensioning member 261 for fixing inside the joint 23; and a fixing column 263 connected to the rear end of the tensioning member 261 for fixing on the rear cover 25.

[0074] In this embodiment, the front cover 24 can fasten the front end of the airbag 21 to the joint 23, and the fixing ring 262 can be clamped in the air passage inside the joint 23; the fixing column 263 can be in threaded cooperation with the rear cover 25, and when the rear cover 25 is tightened with the fixing column 263, the rear cover 25 can be fastened to the rear end of the airbag 21.

[0075] Referring to Figure 1 and Figure 8 , optionally, two parallel guide rods 6 are provided on the base 4; the pipe fitting axial movement mechanism 3 includes: a moving seat 31, with both ends sleeved on the corresponding guide rods 6 respectively; a pipe fitting clamping assembly 32 installed on the moving seat 31 for clamping and fixing the pipe fitting; and a moving seat driving assembly 33 for driving the moving seat 31 to move towards or away from the heating sleeve 1.

[0076] Further, the moving seat driving assembly 33 includes: a motor seat 331, with both ends fixed on the corresponding guide rods 6; a driving motor 332 fixed on the motor seat 331; and a lead screw 333, with one end connected to the output shaft of the driving motor 332 and the other end in threaded cooperation with the moving seat 31.

[0077] In this embodiment, the driving motor 332 drives the lead screw 333 to rotate, thereby driving the moving seat 31 to move on the guide rod 6.

[0078] Further, a cooling device 7 is provided on one side of the heating sleeve 1 on the base 4. The cooling device 7 can be a fan, and after welding is completed, the welded part can be cooled.

[0079] Based on the above embodiments, an embodiment of the present application provides a PFA pipe seamless welding method, including:

[0080] After aligning the ends to be welded of two pipe fittings 100, clamp them inside the heating sleeve 1;

[0081] Place the radial pressure device 2 at the welding part of the pipe fitting 100, and apply a preset radial pressure to the welding part through the radial pressure device 2;

[0082] Heat the welding part through the heating sleeve 1;

[0083] Drive the pipe fitting 100 to move towards each other by a preset distance simultaneously through two pipe fitting axial movement mechanisms 3, so as to apply an axial pressure to the welding part during welding.

[0084] Specifically, before preparing for welding, the two pipe fitting axial movement mechanisms 3 can be reset to the initial position, and it can be, but not limited to, positioning their initial positions through position sensors.

[0085] When preparing for welding, the ends to be welded of the two pipe fittings can be aligned and fixed inside the heating sleeve 1; then place the radial pressure device 2 inside the ends to be welded of the pipe fittings, that is, inside the welding part; finally, move the moving seats 31 of the two pipe fitting axial movement mechanisms 3 towards each other by the same distance, so that the pipe fitting clamping assemblies 32 move to the pipe fittings and clamp and fix the corresponding pipe fittings respectively.

[0086] During welding, the radial pressure device 2 first applies a preset radial pressure to the inner wall of the welding part, and the heating sleeve 1 heats the welding part; when heated to the welding temperature, the two pipe fitting axial movement mechanisms 3 drive the two pipe fittings 100 to move towards each other to compensate for the shrinkage length of the pipe fittings after heating and generate a certain axial pressure.

[0087] After maintaining the radial and axial pressures, turn off the heating device. When the temperature drops to the preset temperature, the pressure can be removed, open the heating sleeve opening and closing assembly 5, and cool the welding part through the cooling device 7 to complete the welding.

[0088] To sum up, the seamless welding machine for PFA pipes of the present invention has high welding quality, the weld has no bubbles, no cracks, and no welding scars; it has a high degree of automation, is easy to operate, reduces labor costs and technical thresholds; it has a wide range of applications and can be used for PFA pipes with different diameters and wall thicknesses; there are no welding scars at the inner wall welding part of the PFA pipe, and it has no influence on the flow rate and flow of gas or liquid.

[0089] It should be noted that each device (components without specific structures described) selected in this application is a general standard part or a part known to those skilled in the art, and its structure and principle can be known to those skilled in the art through technical manuals or obtained through conventional experimental methods.

[0090] In the description of the embodiments of the present invention, unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0091] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0092] Taking the above ideal embodiments of the present invention as an inspiration, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification.

Claims

1. A PFA pipe seamless welding machine, characterized in that: include: A heating sleeve (1) is used to cover the outer periphery of the to-be-welded portion of the pipe (100) to heat the to-be-welded portion; A radial pressure device (2) is used to be arranged on the inner side of the to-be-welded portion of the pipe (100) and to apply radial pressure to the inner wall of the to-be-welded portion during welding; and The two pipe axial moving mechanisms (3) are used to clamp the two pipes (100) and apply axial pressure to the welded portion during welding.

2. The PFA pipe seamless welding machine according to claim 1, characterized in that: The PFA pipe seamless welding machine also includes: Base (4); The heating sleeve opening and closing assembly (5) is arranged on the base (4) and is used to drive the heating sleeve (1) to open or close.

3. The PFA pipe seamless welding machine according to claim 2, characterized in that: The heating sleeve opening and closing assembly (5) comprises: A lower mounting seat (51) is fixed on the base (4) and has a lower mounting groove (511) disposed on the top thereof; An upper mounting seat (52), one end of which is hinged to one side of a lower mounting groove (511) of the lower mounting seat (51), and an upper mounting groove (521) adapted to the lower mounting groove (511) is provided on the bottom surface of the upper mounting seat (52); The heating jacket (1) comprises a lower heating jacket (11) and an upper heating jacket (12) which are respectively arranged in a lower mounting groove (511) and an upper mounting groove (521); wherein When the upper mounting seat (52) and the lower mounting seat (51) are closed, the upper heating sleeve (12) and the lower heating sleeve (11) are closed to form the heating sleeve (1).

4. The PFA pipe seamless welding machine according to claim 3, characterized in that: The upper heating jacket (12) and the lower heating jacket (11) both include: Heating tube (13); A heating element mounting block (131) is arranged on the outer wall of the middle part of the heating tube (13); a heating element (132) is arranged in the heating element mounting block (131); and The mounting block (133) is arranged at the end of the heating tube (13) and is used for being mounted in the corresponding mounting groove.

5. The PFA pipe seamless welding machine according to claim 1, characterized in that: The radial pressure device (2) comprises: The air bag (21) has a connector (23) for connecting to the air nozzle (22) disposed on the inner side of the front end thereof; A front cover (24) and a rear cover (25) are respectively arranged on the outer periphery of both ends of the airbag (21); and An axial tensioning assembly (26) is arranged inside the airbag (21) and is used to tension the two ends of the airbag (21).

6. The PFA pipe seamless welding machine according to claim 5, characterized in that: The axial tensioning assembly (26) comprises: A tensioning member (261); A fixing ring (262) connected to the front end of the tensioning member (261) and used for fixing to the inner side of the joint (23); and The fixing column (263) is connected to the rear end of the tensioning member (261) and is used for fixing on the rear cover (25).

7. The PFA pipe seamless welding machine according to claim 2, characterized in that: The base (4) is provided with two parallel guide rods (6); The pipe axial movement mechanism (3) comprises: A movable seat (31), both ends of which are respectively sleeved on corresponding guide rods (6); A pipe clamping assembly (32) mounted on the movable seat (31); and The movable seat driving assembly (33) is used to drive the movable seat (31) toward or away from the heating sleeve (1).

8. The PFA pipe seamless welding machine according to claim 7, characterized in that: The movable seat driving assembly (33) comprises: A motor base (331), both ends of which are fixed on corresponding guide rods (6); A driving motor (332) is fixed to the motor base (331); and The screw rod (333) has one end connected to the output shaft of the driving motor (332) and the other end threadedly matched with the moving seat (31).

9. The PFA pipe seamless welding machine according to claim 2, characterized in that: A cooling device (7) is provided on the base (4) at one side of the heating sleeve (1).

10. A PFA tube seamless welding method, characterized in that: include: The ends of two pipes (100) to be welded are aligned and clamped in a heating jacket (1); Placing a radial pressure device (2) on the part to be welded of the pipe (100), and applying a preset radial pressure to the part to be welded through the radial pressure device (2); Heating the portion to be welded by means of a heating sleeve (1); The two pipe axial movement mechanisms (3) simultaneously drive the pipes (100) to move towards each other by a preset distance, so as to apply axial pressure to the welded portion during welding.

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